Patent Publication Number: US-2023144909-A1

Title: Prosthetic heart valves with expansion and locking assemblies

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation of a PCT Application No. PCT/US2021/041009, filed Jul. 9, 2021, which claims the benefit of U.S. Provisional Patent Application No. 63/050,292, filed Jul. 10, 2020, where each of above-referenced applications is incorporated herein by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present disclosure relates to implantable, mechanically expandable prosthetic devices, such as prosthetic heart valves, and to assemblies and methods for facilitating change in diameter of such prosthetic devices. 
     BACKGROUND OF THE INVENTION 
     Native heart valves, such as the aortic, pulmonary and mitral valves, function to assure adequate directional flow from and to the heart, and between the heart&#39;s chambers, to supply blood to the whole cardiovascular system. Various valvular diseases can render the valves ineffective and require replacement with artificial valves. Surgical procedures can be performed to repair or replace a heart valve. Surgeries are prone to an abundance of clinical complications, hence alternative less invasive techniques of delivering a prosthetic heart valve over a catheter and implanting it over the native malfunctioning valve, have been developed over the years. 
     Mechanically expandable valves are a category of prosthetic valves that rely on a mechanical actuation mechanism for expansion. The actuation mechanism usually includes a plurality of actuation/locking assemblies, releasably connected to respective actuation members of the valve delivery system, controlled via the handle for actuating the assemblies to expand the valve to a desired diameter. The assemblies may optionally lock the valve&#39;s position to prevent undesired recompression thereof, and disconnection of the delivery system&#39;s actuation member from the valve actuation/locking assemblies, to enable retrieval thereof once the valve is properly positioned at the desired site of implantation. 
     Despite the recent advancements in prosthetic valve technology, there remains a need for improved transcatheter heart valves and delivery systems for such valves. 
     SUMMARY OF THE INVENTION 
     The present disclosure is directed toward devices and assemblies for expanding and locking prosthetic valves, as well as related methods and devices for such assemblies. In several embodiments, the disclosed assemblies are configured for delivering replacement heart valves into a heart of a patient, wherein the replacement heart valves may be expanded and locked in a desired diameter at the implantation site. 
     According to one aspect of the invention, there is provided a prosthetic valve comprising a frame movable between a radially compressed and a radially expanded configuration, and at least one expansion and locking mechanism. The at least one expansion and locking mechanism comprises an outer member, an inner member, and at least one plate comprising a primary aperture, disposed around the inner member. The outer member is coupled to the frame at a first location. The inner member is coupled to the frame at a second location spaced apart from the first location, the inner member extending at least partially into the outer member. The at least one plate is configured to transition between an angled locking orientation and a non-locking orientation. 
     The movement of the inner member in a first direction, relative to the outer member, causes the frame to foreshorten axially and expand radially in a non-locking orientation of the at least one plate. In the absence of a force applied to the plate in the first direction, movement of the inner member in a second direction, relative to the outer member, causes the at least one plate to assume the angled locking orientation. 
     The at least one plate is configured to inhibit advancement of the inner member in the second direction relative to the outer member, when oriented in the angled locking orientation. 
     According to some embodiments, the outer member further comprises a chamber comprising a proximal chamber wall and a distal chamber wall, wherein the at least one plate is disposed within the chamber. 
     According to some embodiments, the outer member further comprises a lateral opening exposing at least a portion of the chamber. 
     According to some embodiments, the at least one plate has a disc-like circular or elliptic shape. 
     According to some embodiments, the at least one plate has a rectangular shape. 
     According to some embodiments, the at least one plate comprises a rigid material. 
     According to some embodiments, the at least one plate comprises a plurality of plates. 
     According to some embodiments, the distal chamber wall comprises at least one angled portion. 
     According to some embodiments, the angle formed between the angled portion and the inner member is more acute than the angle formed between the plate and the inner member in the angled locking orientation. 
     According to some embodiments, the diameter of the primary aperture is closely matched with the outer diameter of the inner member extending therethrough, such that axial movement of the inner member frictionally engages with the primary aperture. 
     According to some embodiments, the diameter of the primary aperture is no more than 5 percent larger than the diameter of the inner member at the portion extending therethrough. 
     According to some embodiments, at least a portion of the proximal chamber wall is substantially orthogonal to a longitudinal axis of the inner member. 
     According to some embodiments, the outer member comprises a primary channel, configured to accommodate at least a portion of the inner member therein. 
     According to some embodiments, the outer member further comprises a spring disposed within the chamber, configured to urge the at least one plate in the second direction. 
     According to some embodiments, the spring is a helical spring coiled around the inner member. 
     According to some embodiments, the spring is a helical spring disposed adjacent the inner member. 
     According to some embodiments, the spring is a leaf spring. 
     According to some embodiments, the plate is coupled to the proximal chamber wall via a plate hinge, and wherein the plate is configured to pivot about the plate hinge between the angled locking orientation and the non-locking orientation. 
     According to some embodiments, the distal chamber wall comprises a proximally oriented protrusion. 
     According to some embodiments, the at least one expansion and locking mechanism further comprises a release member, extending at least partially into the outer member. The release member is coupled to the at least one plate, and configured to transition the at least one plate to the non-locking orientation, and/or retain the at least one plate in the non-locking orientation, when the release member is pulled in the second direction relative to the outer member. 
     According to some embodiments, the outer member further comprises a release channel, configured to accommodate the release member therein. 
     According to some embodiments, the plate further comprises a release aperture, wherein a distal end portion of the release member extends through the release aperture, and wherein a distal end of the release member comprises a retention feature distal to the release aperture 
     According to some embodiments, the distal chamber wall comprises a niche dimensioned to accommodate the retention feature. 
     According to some embodiments, a distal end of the release member is pivotably coupled to the at least one plate via a release member distal hinge. 
     According to some embodiments, the outer member further comprises a first spring and a second spring, disposed within the chamber at opposite sides of the inner member, wherein the first spring is configured to bias one side of the at least one plate in a first direction, and the second spring is configured to bias an opposite second side of the at least one plate in a second direction, thereby biasing the plate to the angled locking orientation in a free state of the first and second springs. 
     According to some embodiments, the first spring is a compression spring, disposed between the at least one plate and the distal chamber wall, and wherein the second spring is an extension spring disposed between the at least one plate and the distal chamber wall. 
     According to some embodiments, the outer member further comprises an outer member fastener extending radially outward, wherein the outer member is coupled to the frame at the first location via the outer member fastener. 
     According to some embodiments, the inner member further comprises an inner member fastener extending radially outward, wherein the inner member is coupled to the frame at the second location via the inner member fastener. 
     According to some embodiments, the frame comprises intersecting struts. 
     According to another aspect of the invention, there is provided a prosthetic valve comprising a frame movable between a radially compressed and a radially expanded configuration, and at least one expansion and locking mechanism. The at least one expansion and locking mechanism comprises an outer member, an inner member, at least one plate comprising a primary aperture disposed around the inner member, and at least one spring disposed between the outer member and the at least one plate. The outer member is coupled to the frame at a first location. The inner member is coupled to the frame at a second location spaced apart from the first location, the inner member extending at least partially into the outer member. The at least one plate is configured to transition between an angled locking orientation and a non-locking orientation. 
     The movement of the inner member in a first direction, relative to the outer member, causes the frame to foreshorten axially and expand radially in a non-locking orientation of the at least one plate. In the absence of a force applied to the plate in the first direction, the at least one spring is configured to bias the at least one plate to the angled locking orientation. 
     The at least one plate is configured to inhibit advancement of the inner member in the second direction relative to the outer member, when oriented in the angled locking orientation. 
     According to some embodiments, the at least one plate has a disc-like circular or elliptic shape. 
     According to some embodiments, the at least one plate has a rectangular shape. 
     According to some embodiments, the at least one plate comprises a rigid material. 
     According to some embodiments, the at least one plate comprises a plurality of plates. 
     According to some embodiments, the diameter of the primary aperture is no more than 5 percent larger than the diameter of the inner member at the portion extending therethrough. 
     According to some embodiments, the outer member comprises a primary channel, configured to accommodate at least a portion of the inner member therein. 
     According to some embodiments, the outer member further comprises a chamber comprising a proximal chamber wall and a distal chamber wall, wherein the at least one plate and the at least one spring are disposed within the chamber. 
     According to some embodiments, the distal chamber wall comprises a proximally oriented protrusion. 
     According to some embodiments, the distal chamber wall comprises at least one angled portion. 
     According to some embodiments, the angle formed between the angled portion and the inner member is more acute than the angle formed between the plate and the inner member in the angled locking orientation. 
     According to some embodiments, at least a portion of the proximal chamber wall is substantially orthogonal to a longitudinal axis of the inner member. 
     According to some embodiments, the at least one spring comprises a helical spring coiled around the inner member. 
     According to some embodiments, the coiled spring is a compression spring disposed between the proximal chamber wall and the at least one plate. 
     According to some embodiments, the at least one spring comprises at least one helical spring disposed adjacent the inner member. 
     According to some embodiments, the at least one helical spring is a compression spring disposed between the proximal chamber wall and the at least one plate. 
     According to some embodiments, the at least one helical spring is an extension spring disposed between the distal chamber wall and the at least one plate. 
     According to some embodiments, the at least one spring is a leaf spring. 
     According to some embodiments, the at least one expansion and locking mechanism further comprises a release member, extending at least partially into the outer member, the release member coupled to the at least one plate, and configured to transition the at least one plate to the non-locking orientation, and/or retain the at least one plate in the non-locking orientation, when the release member is pulled in the second direction relative to the outer member. 
     According to some embodiments, the outer member further comprises a release channel, configured to accommodate the release member therein. 
     According to some embodiments, the at least one plate further comprises a release aperture, wherein a distal end portion of the release member extends through the release aperture, and wherein a distal end of the release member comprises a retention feature distal to the release aperture. 
     According to some embodiments, the distal chamber wall comprises a niche dimensioned to accommodate the retention feature. 
     According to some embodiments, a distal end of the release member is pivotably coupled to the at least one plate via a release member distal hinge. 
     According to some embodiments, the at least one spring comprises a first spring and a second spring, both of which are disposed within the chamber at opposite sides of the inner member, wherein the first spring is configured to bias one side of the at least one plate in a first direction, and the second spring is configured to bias an opposite second side of the at least one plate in a second direction, thereby biasing the plate to the angled locking orientation in a free state of the first and second springs. 
     According to some embodiments, the first spring is a compression spring, disposed between the at least one plate and the distal chamber wall, and wherein the second spring is an extension spring disposed between the at least one plate and the distal chamber wall. 
     According to yet another aspect of the invention, there is provided a delivery assembly comprising a prosthetic valve and a delivery apparatus. The prosthetic valve comprises a frame movable between a radially compressed and a radially expanded configuration, and at least one expansion and locking mechanism. The at least one expansion and locking mechanism comprises an outer member, an inner member, and at least one plate comprising a primary aperture, disposed around the inner member. The outer member is coupled to the frame at a first location. The inner member is coupled to the frame at a second location spaced apart from the first location, the inner member extending at least partially into the outer member. The at least one plate is configured to transition between an angled locking orientation and a non-locking orientation. 
     The delivery apparatus comprises a handle, a delivery shaft extending distally from the handle, and at least one actuation assembly extending from the handle through the delivery shaft, and detachably coupled to the at least one expansion and locking assembly. 
     The frame is movable from the radially compressed configuration to the radially expanded configuration upon actuating the at least one expansion and locking assembly by the at least one actuation assembly. The movement of the inner member in a first direction, relative to the outer member, causes the frame to foreshorten axially and expand radially in a non-locking orientation of the at least one plate. 
     In the absence of a force applied to the plate in the first direction, movement of the inner member in a second direction, relative to the outer member, causes the at least one plate to assume the angled locking orientation. The at least one plate is configured to inhibit advancement of the inner member in the second direction relative to the outer member, when oriented in the angled locking orientation. 
     According to some embodiments, the at least one actuation assembly comprises an actuation member and an actuation support sleeve disposed around the actuation member, wherein the actuation member and the actuation support sleeve are movable longitudinally relative to each other in a telescoping manner. 
     According to some embodiments, the at least one actuation member is chosen from: a wire, a cable, a rod, or a tube. 
     According to some embodiments, the actuation support sleeve is a tube or a sheath having sufficient rigidity, such that the actuation support sleeve can apply an axial force against the outer member without bending or buckling. 
     According to some embodiments, the at least one actuation member is threadedly engaged with the corresponding inner member. 
     According to some embodiments, the handle comprises a plurality of knobs. 
     According to some embodiments, at least one of the plurality of knobs is configured to axially move each actuation member relative to the respective actuation support sleeve. 
     According to some embodiments, at least one of the plurality of knobs is configured to disengage each actuation assembly from the respective expansion and locking assembly. 
     According to some embodiments, the outer member further comprises a chamber comprising a proximal chamber wall and a distal chamber wall, and wherein the at least one plate is disposed within the chamber. 
     According to some embodiments, the at least one plate has a disc-like circular or elliptic shape. 
     According to some embodiments, the at least one plate has a rectangular shape. 
     According to some embodiments, the at least one plate comprises a rigid material. 
     According to some embodiments, the at least one plate comprises a plurality of plates. 
     According to some embodiments, the distal chamber wall comprises at least one angled portion. 
     According to some embodiments, the angle formed between the angled portion and the inner member is more acute than the angle formed between the plate and the inner member in the angled locking orientation. 
     According to some embodiments, the diameter of the primary aperture is closely matched with the outer diameter of the inner member extending therethrough, such that axial movement of the inner member frictionally engages with the primary aperture. 
     According to some embodiments, the diameter of the primary aperture is no more than 5 percent larger than the diameter of the inner member at the portion extending therethrough. 
     According to some embodiments, at least a portion of the proximal chamber wall is substantially orthogonal to a longitudinal axis of the inner member. 
     According to some embodiments, the outer member comprises a primary channel, configured to accommodate at least a portion of the inner member and at least a portion of the actuation member therein. 
     According to some embodiments, the outer member further comprises a spring disposed within the chamber, configured to urge the at least one plate in the second direction. 
     According to some embodiments, the spring is a helical spring coiled around the inner member. 
     According to some embodiments, the spring is a helical spring disposed adjacent the inner member. 
     According to some embodiments, the spring is a leaf spring. 
     According to some embodiments, the plate is coupled to the proximal chamber wall via a plate hinge, wherein the plate is configured to pivot about the plate hinge between the angled locking orientation and the non-locking orientation. 
     According to some embodiments, the distal chamber wall comprises a proximally oriented protrusion. 
     According to yet another aspect of the invention, there is provided a delivery assembly comprising a prosthetic valve and a delivery apparatus. The prosthetic valve comprises a frame movable between a radially compressed and a radially expanded configuration, and at least one expansion and locking mechanism. The at least one expansion and locking mechanism comprises an outer member, an inner member, a release member, and at least one plate comprising a primary aperture, disposed around the inner member. 
     The outer member is coupled to the frame at a first location. The inner member is coupled to the frame at a second location spaced apart from the first location, the inner member extending at least partially into the outer member. The release member extends at least partially into the outer member, and is coupled to the at least one plate. The at least one plate is configured to transition between an angled locking orientation and a non-locking orientation. 
     The delivery apparatus comprises a handle, a delivery shaft extending distally from the handle, at least one actuation assembly extending from the handle through the delivery shaft, and detachably coupled to the at least one expansion and locking assembly, and at least one release assembly extending from the handle through the delivery shaft, and detachably coupled to the at least one release member. 
     The frame is movable from the radially compressed configuration to the radially expanded configuration upon actuating the at least one expansion and locking assembly by the at least one actuation assembly. The movement of the inner member in a first direction, relative to the outer member, causes the frame to foreshorten axially and expand radially in a non-locking orientation of the at least one plate. 
     In the absence of a force applied to the plate in the first direction, movement of the inner member in a second direction, relative to the outer member, causes the at least one plate to assume the angled locking orientation. The at least one plate is configured to inhibit advancement of the inner member in the second direction relative to the outer member, when oriented in the angled locking orientation. 
     The release member is configured to transition the at least one plate to the non-locking orientation, and/or retain the at least one plate in the non-locking orientation, when the release member is pulled by the release assembly in the first direction relative to the outer member. 
     According to some embodiments, the at least one actuation assembly comprises an actuation member and an actuation support sleeve disposed around the actuation member, wherein the actuation member and the support sleeve are movable longitudinally relative to each other in a telescoping manner. 
     According to some embodiments, the at least one actuation member is chosen from: a wire, a cable, a rod, or a tube. 
     According to some embodiments, the support sleeve is a tube or a sheath having sufficient rigidity, such that the support sleeve can apply an axial force against the frame without bending or buckling. 
     According to some embodiments, the at least one actuation member is threadedly engaged with the corresponding inner member. 
     According to some embodiments, the at least one release assembly comprises a release arm and a release support sleeve disposed around the release arm, and wherein the release arm and the release support sleeve are movable longitudinally relative to each other in a telescoping manner. 
     According to some embodiments, the at least one release arm is chosen from: a wire, a cable, a rod, or a tube. 
     According to some embodiments, the release support sleeve is a tube or a sheath having sufficient rigidity, such that the release support sleeve can apply an axial force against the outer member without bending or buckling. 
     According to some embodiments, the at least one release arm is threadedly engaged with the corresponding release member. 
     According to some embodiments, the handle comprises a plurality of knobs. 
     According to some embodiments, at least one of the plurality of knobs is configured to axially move each actuation member relative to the respective actuation support sleeve. 
     According to some embodiments, at least one of the plurality of knobs is configured to axially move each release arm relative to the respective release support sleeve. 
     According to some embodiments, at least one of the plurality of knobs is configured to disengage each actuation assembly from the respective expansion and locking assembly. 
     According to some embodiments, at least one of the plurality of knobs is configured to disengage each release assembly from the respective expansion and locking assembly. 
     According to some embodiments, the outer member further comprises a chamber comprising a proximal chamber wall and a distal chamber wall, and wherein the at least one plate is disposed within the chamber. 
     According to some embodiments, the at least one plate has a disc-like circular or elliptic shape. 
     According to some embodiments, the at least one plate has a rectangular shape. 
     According to some embodiments, the at least one plate comprises a rigid material. 
     According to some embodiments, the at least one plate comprises a plurality of plates. 
     According to some embodiments, the distal chamber wall comprises at least one angled portion. 
     According to some embodiments, the angle formed between the angled portion and the inner member is more acute than the angle formed between the plate and the inner member in the angled locking orientation. 
     According to some embodiments, the diameter of the primary aperture is closely matched with the outer diameter of the inner member extending therethrough, such that axial movement of the inner member frictionally engages with the primary aperture. 
     According to some embodiments, the diameter of the primary aperture is no more than 5 percent larger than the diameter of the inner member at the portion extending therethrough. 
     According to some embodiments, at least a portion of the proximal chamber wall is substantially orthogonal to a longitudinal axis of the inner member. 
     According to some embodiments, the outer member comprises a primary channel, configured to accommodate at least a portion of the inner member and at least a portion of the actuation member therein. 
     According to some embodiments, the outer member comprises a release channel, configured to accommodate at least a portion of the release member and at least a portion of the release arm therein. 
     According to some embodiments, the outer member further comprises a spring disposed within the chamber, configured to urge the at least one plate in the second direction. 
     According to some embodiments, the spring is a helical spring coiled around the inner member. 
     According to some embodiments, the spring is a helical spring disposed adjacent the inner member. 
     According to some embodiments, the spring is a leaf spring. 
     According to some embodiments, the plate is coupled to the proximal chamber wall via a plate hinge, wherein the plate is configured to pivot about the plate hinge between the angled locking orientation and the non-locking orientation. 
     According to some embodiments, the distal chamber wall comprises a proximally oriented protrusion. 
     According to some embodiments, the at least one plate further comprises a release aperture, wherein a distal end portion of the release member extends through the release aperture, and wherein a distal end of the release member comprises a retention feature distal to the release aperture. 
     According to some embodiments, the distal chamber wall comprises a niche dimensioned to accommodate the retention feature. 
     According to some embodiments, a distal end of the release member is pivotably coupled to the at least one plate via a release member distal hinge. 
     According to some embodiments, the outer member comprises a first spring and a second spring, disposed within the chamber at opposite sides of the inner member, wherein the first spring is configured to bias one side of the at least one plate in a first direction, and the second spring is configured to bias an opposite second side of the at least one plate in a second direction, thereby biasing the plate to the angled locking orientation in a free state of the first and second springs. 
     According to some embodiments, the first spring is a compression spring, disposed between the at least one plate and the distal chamber wall, and wherein the second spring is an extension spring disposed between the at least one plate and the distal chamber wall. 
     According to yet another aspect of the invention, there is provided a method of implanting a prosthetic valve, the method comprises positioning a prosthetic valve at a target site in a patient&#39;s body using a delivery apparatus. The method further comprises radially expanding the prosthetic valve from a radially compressed configuration to a radially expanded configuration; The method further comprises locking the expansion and locking assembly. 
     The prosthetic valve comprises at least one expansion and locking assembly, wherein the expansion and locking assembly comprising an outer member, an inner member partially disposed within, and movable axially relative to, the outer member, and at least one plate dispose within the outer member and around the inner member. The delivery apparatus comprises at least one actuation assembly, detachably coupled to the at least one expansion and locking assembly. 
     Radially expanding the prosthetic valve includes applying, via the at least one actuation assembly, a pull force on the inner member, configured to axially move the inner member in a first direction relative to the outer member. 
     Locking the expansion and locking assembly includes releasing the pull force exerted on the inner member by the actuation assembly, thereby allowing the at least one plate to assume an angled locking orientation. 
     According to some embodiments, the radially expanded configuration comprises partially expanded configurations and/or a fully expanded configuration, wherein the step of radially expanding the prosthetic valve is executed again after the locking step, so as to reorient the at least one plate from the angled locking orientation to a non-locking orientation, allowing further expansion of the prosthetic valve from a partially expanded configuration to another partially expanded configuration or to a fully expanded configuration. 
     According to some embodiments, the at least one actuation assembly comprises an actuation member detachably coupled to the inner member, and an actuation support sleeve disposed around the actuation member, wherein the step of radially expanding the prosthetic valve comprises exerting a pull force to move the actuation member in a first direction relative to the actuation support sleeve, while keeping the actuation support sleeve stationary or moved in an opposite second direction, so as to apply a counter force against the outer member. 
     According to some embodiments, the method further comprising a step of detaching the at least one actuation member from the at least one inner member, and retrieving the delivery apparatus from the patient&#39;s body. 
     According to some embodiments, the at least one actuation member is threadedly engaged with the at least one inner member, wherein detaching the at least one actuation member comprises rotating the at least one actuation member around a longitudinal axis thereof. 
     According to yet another aspect of the invention, there is provided a method of implanting a prosthetic valve, the method comprises positioning a prosthetic valve at a target site in a patient&#39;s body using a delivery apparatus. The method further comprises radially expanding the prosthetic valve from a radially compressed configuration to a radially expanded configuration. The method further comprises locking the expansion and locking assembly. The method further comprises unlocking the expansion and locking assembly. The method further comprises re-compressing the prosthetic valve. 
     The prosthetic valve comprises at least one expansion and locking assembly, wherein the expansion and locking assembly comprising an outer member, an inner member partially disposed within, and movable axially relative to, the outer member, at least one plate dispose within the outer member and around the inner member, and a release member disposed within the outer member and axially movable relative thereto. The release member is coupled to the at least one plate 
     The delivery apparatus comprises at least one actuation assembly detachably coupled to the at least one expansion and locking assembly, and at least one release assembly detachably coupled to the release member. 
     Radially expanding the prosthetic valve includes applying, via the at least one actuation assembly, a pull force on the inner member, configured to axially move the inner member in a first direction relative to the outer member. 
     Locking the expansion and locking assembly includes releasing the pull force exerted on the inner member by the actuation assembly, thereby allowing the at least one plate to assume an angled locking orientation. 
     Unlocking the expansion and locking assembly includes applying, via the at least one release assembly, a pull force on the release member, configured to transition the at least one plate from the angled locking orientation to a non-locking orientation. Re-compressing the prosthetic valve is executed such that the at least one inner member is moved in a second direction relative to the at least one outer member. 
     According to some embodiments, any of the steps of radially expanding the prosthetic valve, locking, unlocking, and re-compressing the prosthetic valve, are repeated for any desired number of times and in any order, so as to reach a final desired expansion diameter of the prosthetic valve. 
     According to some embodiments, the method further comprises a step of re-positioning the prosthetic valve using the delivery apparatus, after the step of re-compressing the prosthetic valve. 
     According to some embodiments, the at least one actuation assembly comprises an actuation member detachably coupled to the inner member, and an actuation support sleeve disposed around the actuation member. The at least one release assembly comprises a release arm detachably coupled to the release member, and a release support sleeve disposed around the release arm. 
     The step of radially expanding the prosthetic valve comprises exerting a pull force to move the actuation member in a first direction relative to the actuation support sleeve, while keeping the actuation support sleeve stationary or moved in an opposite second direction, so as to apply a counter force against the outer member 
     The step of unlocking the prosthetic valve comprises exerting a pull force to move the release arm in a first direction relative to the release support sleeve, while keeping the release support sleeve stationary or moved in an opposite second direction, so as to apply a counter force against the outer member. 
     According to some embodiments, the method further comprises steps of detaching the at least one actuation member from the at least one inner member, detaching the at least one release arm from the release member, and retrieving the delivery apparatus from the patient&#39;s body. 
     According to some embodiments, the at least one actuation member is threadedly engaged with the at least one inner member, and the at least one release arm is threadedly engaged with the at least one release member. Detaching the at least one actuation member comprises rotating the at least one actuation member around a longitudinal axis thereof, and detaching the at least one release arm comprises rotating the at least one release arm around a longitudinal axis thereof. 
     According to another aspect of the invention, there is provided a method for assembling an expansion and locking mechanism, comprising the steps of: (i) providing an outer member comprising a chamber and a lateral opening exposing at least a portion of the chamber; (ii) inserting at least one plate, comprising a primary aperture, into the chamber through the lateral opening; (iii) orienting the at least one plate in a substantially orthogonal orientation, relative to a longitudinal axis of the outer member; and (iv) inserting the inner member into the outer member, through the primary aperture of the at least one plate. 
     The various innovations of this disclosure can be used in combination or separately. This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. The foregoing and other objects, features, and advantages of the invention will become more apparent from the following detailed description, which proceeds with reference to the accompanying figures. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       Some embodiments of the invention are described herein with reference to the accompanying figures. The description, together with the figures, makes apparent to a person having ordinary skill in the art how some embodiments may be practiced. The figures are for the purpose of illustrative description and no attempt is made to show structural details of an embodiment in more detail than is necessary for a fundamental understanding of the invention. For the sake of clarity, some objects depicted in the figures are not to scale. 
       In the Figures: 
         FIG.  1    shows a view in perspective of a delivery assembly comprising a delivery apparatus carrying a prosthetic valve, according to some embodiments. 
         FIG.  2    shows a view in perspective of a prosthetic valve, according to some embodiments. 
         FIG.  3 A  shows a view in perspective of a prosthetic valve in a partially compressed configuration, having a plurality of expansion and locking assemblies attached to corresponding actuation assemblies, according to some embodiments. 
         FIG.  3 B  shows a view in perspective of the prosthetic valve of  FIG.  3 A , and a fully expanded configuration. 
         FIG.  4    shows a view in perspective of an expansion and locking assembly, according to some embodiments. 
         FIG.  5 A  shows a view in perspective of an inner member, according to some embodiments. 
         FIG.  5 B  shows a view in perspective of an expansion and locking assembly, according to some embodiments. 
         FIGS.  6 A- 6 C  show various types and configurations of plates, according to some embodiments. 
         FIGS.  7 A- 7 D  show cross-sectional views of an expansion and locking assembly in different operational states thereof, according to some embodiments. 
         FIGS.  8 A- 8 C  show cross-sectional views of a portion of an expansion and locking assembly containing the chamber, provided with various types and arrangements of a helical spring, according to some embodiments. 
         FIGS.  9 A- 9 B  show cross-sectional views of an expansion and locking assembly containing the chamber, provided with a leaf spring shown in two states thereof, according to some embodiments. 
         FIGS.  10 A- 10 B  show cross-sectional views of an expansion and locking assembly containing the chamber, provided with a plate pivotably attached to a proximal chamber wall shown in two states thereof, according to some embodiments. 
         FIG.  11    shows a cross-sectional view of a portion of an expansion and locking assembly containing the chamber, provided with a proximally oriented protrusion extending from the distal chamber wall, according to some embodiments. 
         FIGS.  12 A- 12 B  show cross-sectional views of an expansion and locking assembly provided with a plurality of plates, in different operational states thereof, according to some embodiments. 
         FIG.  13    shows a view in perspective of a delivery assembly comprising a delivery apparatus carrying a prosthetic valve, wherein the delivery apparatus further comprises a plurality of release assemblies, according to some embodiments. 
         FIG.  14    shows a view in perspective of a prosthetic valve having a plurality of expansion and locking assemblies, attached to corresponding actuation assemblies and release assemblies, according to some embodiments. 
         FIG.  15 A  shows a view in perspective of an inner member and a release member, extending through apertures of a plate, according to some embodiments. 
         FIG.  15 B  shows a view in perspective of an expansion and locking assembly comprising a release member, according to some embodiments. 
         FIGS.  16 A- 16 D  show cross-sectional views of an expansion and locking assembly in different operational states thereof, according to some embodiments. 
         FIG.  17 A  shows an enlarged cross-sectional view of a portion of an expansion and locking assembly containing the chamber, corresponding to the state shown in  FIG.  16 B or  16 D . 
         FIG.  17 B  shows an enlarged cross-sectional view of a portion of another embodiments of an expansion and locking assembly. 
         FIGS.  18 A- 18 D  show cross-sectional view of an expansion and locking assembly in different operational states thereof, according to other embodiments. 
         FIG.  19 A  shows an enlarged cross-sectional view of a portion of an expansion and locking assembly containing the chamber, corresponding to the state shown in  FIG.  18 B or  18 D . 
         FIG.  19 B  shows an enlarged cross-sectional view of a portion of another embodiment of an expansion and locking assembly. 
         FIG.  20 A  shows an enlarged cross-sectional view of an expansion and locking assembly, comprising two springs residing within the chamber, in a free state of the springs, according to some embodiments. 
         FIG.  20 B  shows an enlarged cross-sectional view of the expansion and locking assembly of  FIG.  20 A , in a released state of the plate. 
     
    
    
     DETAILED DESCRIPTION OF SOME EMBODIMENTS 
     For purposes of this description, certain aspects, advantages, and novel features of the embodiments of this disclosure are described herein. The disclosed methods, apparatus, and systems should not be construed as being limiting in any way. Instead, the present disclosure is directed toward all novel and nonobvious features and aspects of the various disclosed embodiments, alone and in various combinations and sub-combinations with one another. The methods, apparatus, and systems are not limited to any specific aspect or feature or combination thereof, nor do the disclosed embodiments require that any one or more specific advantages be present, or problems be solved. The technologies from any example can be combined with the technologies described in any one or more of the other examples. In view of the many possible embodiments to which the principles of the disclosed technology may be applied, it should be recognized that the illustrated embodiments are only preferred examples and should not be taken as limiting the scope of the disclosed technology. 
     Although the operations of some of the disclosed embodiments are described in a particular, sequential order for convenient presentation, it should be understood that this manner of description encompasses rearrangement, unless a particular ordering is required by specific language set forth below. For example, operations described sequentially may in some cases be rearranged or performed concurrently. Moreover, for the sake of simplicity, the attached figures may not show the various ways in which the disclosed methods can be used in conjunction with other methods. Additionally, the description sometimes uses terms like “provide” or “achieve” to describe the disclosed methods. These terms are high-level abstractions of the actual operations that are performed. The actual operations that correspond to these terms may vary depending on the particular implementation and are readily discernible by one of ordinary skill in the art. 
     As used in this application and in the claims, the singular forms “a,” “an,” and “the” include the plural forms unless the context clearly dictates otherwise. Additionally, the terms “have” or “includes” means “comprises.” As used herein, “and/or” means “and” or “or,” as well as “and” and “or”. 
     Directions and other relative references may be used to facilitate discussion of the drawings and principles herein, but are not intended to be limiting. For example, certain terms may be used such as “inner,” “outer,” “upper,” “lower,” “inside,” “outside,”, “top,” “bottom,” “interior,” “exterior,” “left,” right,” and the like. Such terms are used, where applicable, to provide some clarity of description when dealing with relative relationships, particularly with respect to the illustrated embodiments. Such terms are not, however, intended to imply absolute relationships, positions, and/or orientations. For example, with respect to an object, an “upper” part can become a “lower” part simply by turning the object over. Nevertheless, it is still the same part and the object remains the same. 
     Throughout the figures of the drawings, different superscripts for the same reference numerals are used to denote different embodiments of the same elements. Embodiments of the disclosed devices and systems may include any combination of different embodiments of the same elements. Specifically, any reference to an element without a superscript may refer to any alternative embodiment of the same element denoted with a superscript. In order to avoid undue clutter from having too many reference numbers and lead lines on a particular drawing, some components will be introduced via one or more drawings and not explicitly identified in every subsequent drawing that contains that component. 
       FIG.  1    shows a view in perspective of a delivery assembly  10 , according to some embodiments. The delivery assembly  10  can include a prosthetic valve  100  and a delivery apparatus  12 . The prosthetic valve  100  can be on or releasably coupled to the delivery apparatus  12 . The delivery apparatus can include a handle  30  at a proximal end thereof, a nosecone shaft  24  extending distally from the handle  30 , a nosecone  26  attached to the distal end of the nosecone shaft  24 , a delivery shaft  22  extending over the nosecone shaft  24 , and optionally an outer shaft  20  extending over the delivery shaft  22 . 
     The term “proximal”, as used herein, generally refers to the side or end of any device or a component of a device, which is closer to the handle  30  or an operator of the handle  30  when in use. 
     The term “distal”, as used herein, generally refers to the side or end of any device or a component of a device, which is farther from the handle  30  or an operator of the handle  30  when in use. 
     The term “prosthetic valve”, as used herein, refers to any type of a prosthetic valve deliverable to a patient&#39;s target site over a catheter, which is radially expandable and compressible between a radially compressed, or crimped, configuration, and a radially expanded configuration. Thus, a prosthetic valve  100  can be crimped or retained by a delivery apparatus  12  in a compressed configuration during delivery, and then expanded to the expanded configuration once the prosthetic valve  100  reaches the implantation site. The expanded configuration may include a range of diameters to which the valve may expand, between the compressed configuration and a maximal diameter reached at a fully expanded configuration. Thus, a plurality of partially expanded configurations may relate to any expansion diameter between radially compressed or crimped configuration, and maximally expanded configuration. 
     The term “plurality”, as used herein, means more than one. 
     A prosthetic valve  100  of the current disclosure may include any prosthetic valve configured to be mounted within the native aortic valve, the native mitral valve, the native pulmonary valve, and the native tricuspid valve. While a delivery assembly  10  described in the current disclosure, includes a delivery apparatus  12  and a prosthetic valve  100 , it should be understood that the delivery apparatus  12  according to any embodiment of the current disclosure can be used for implantation of other prosthetic devices aside from prosthetic valves, such as stents or grafts. 
     According to some embodiments, the prosthetic valve  100  is a mechanically expandable valve, and the delivery apparatus  12 , such as the delivery apparatus  12   a  of a delivery assembly  10   a  shown in  FIG.  1   , further comprises a plurality of actuation assemblies  40  extending from the handle  30   a  through the delivery shaft  22 . In the illustrated embodiment, the prosthetic valve  100  has three actuation assemblies  40 , however, in other embodiments a greater or fewer number of actuation assemblies  40  can be used. 
     Each actuation assembly  40  can generally include an actuation member  42  (hidden from view in  FIG.  1   , visible in  FIGS.  7 A- 7 D ) releasably coupled at its distal end  44  to respective expansion and locking assembly  140  of the valve  100 , and an actuation support sleeve  46  disposed around the corresponding actuation member  42 . The actuation member  42  and the actuation support sleeve  46  can be movable longitudinally relative to each other in a telescoping manner to radially expand and contract the frame  106 , as further described in U.S. Publication Nos. 2018/0153689, 2018/0153689 and 2018/0325665 which are incorporated herein by reference. The actuation members  42  can be, for example, wires, cables, rods, or tubes. The actuation support sleeves  46  can be, for example, tubes or sheaths having sufficient rigidity such that they can apply a distally directed force to the frame without bending or buckling. 
     The prosthetic valve  100  can be delivered to the site of implantation via a delivery assembly  10  carrying the valve  100  in a radially compressed or crimped configuration, toward the target site, to be mounted against the native anatomy, by expanding the valve  100  via a mechanical expansion mechanism, as will be elaborated below. 
     The delivery assembly  10  can be utilized, for example, to deliver a prosthetic aortic valve for mounting against the aortic annulus, to deliver a prosthetic mitral valve for mounting against the mitral annulus, or to deliver a prosthetic valve for mounting against any other native annulus. 
     The nosecone  26  can be connected to the distal end of the nosecone shaft  24 . A guidewire (not shown) can extend through a central lumen of the nosecone shaft  24  and an inner lumen of the nosecone  26 , so that the delivery apparatus  12  can be advanced over the guidewire through the patient&#39;s vasculature. 
     A distal end portion of the outer shaft  20  can extend over the prosthetic valve  100  and contact the nosecone  26  in a delivery configuration of the delivery apparatus  12 . Thus, the distal end portion of the outer shaft  20  can serve as a delivery capsule that contains, or houses, the prosthetic valve  100  in a radially compressed or crimped configuration for delivery through the patient&#39;s vasculature. 
     The outer shaft  20  and the delivery shaft  22  can be configured to be axially movable relative to each other, such that a proximally oriented movement of the outer shaft  20  relative to the delivery shaft  22 , or a distally oriented movement of the delivery shaft  22  relative to the outer shaft  20 , can expose the prosthetic valve  100  from the outer shaft  20 . In some configurations, the prosthetic valve  100  is not housed within the outer shaft  20  during delivery. Thus, according to some optional configurations, the delivery apparatus  12  does not necessarily include an outer shaft  20 . 
     As mentioned above, the proximal ends of the nosecone shaft  24 , the delivery shaft  22 , components of the actuation assemblies  40 , and when present—the outer shaft  20 , can be coupled to the handle  30 . During delivery of the prosthetic valve  100 , the handle  30  can be maneuvered by an operator (e.g., a clinician or a surgeon) to axially advance or retract components of the delivery apparatus  12 , such as the nosecone shaft  24 , the delivery shaft  22 , and/or the outer shaft  20 , through the patient&#39;s vasculature, as well as to expand or contract the prosthetic valve  100 , for example by maneuvering the actuation assemblies  40 , and to disconnect the prosthetic valve  100  from the delivery apparatus  12 , for example—by decoupling the actuation members  42  from the expansion and locking assemblies  140  of the valve  100 , in order to retract it once the prosthetic valve  100  is mounted in the implantation site. 
     According to some embodiments, the handle  30  can include one or more operating interfaces, such as steerable or rotatable adjustment knobs  32 , levers, sliders, buttons and other actuating mechanisms, which are operatively connected to different components of the delivery apparatus  12  and configured to produce axial movement of the delivery apparatus  12  in the proximal and distal directions, as well as to expand or contract the prosthetic valve  100  via various adjustment and activation mechanisms as will be further described below. 
     The handle  30  may further comprises one or more visual or auditory informative elements (not shown) configured to provide visual or auditory information and/or feedback to a user or operator of the delivery apparatus  12 , such as a display, LED lights, speakers and the like. 
       FIG.  2    shows an exemplary mechanically expandable prosthetic valve  100  in an expanded configuration, according to some embodiments. The prosthetic valve  100  can comprise an inflow end portion  104  defining an inflow end  105 , and an outflow end portion  102  defining an outflow end  103 . The prosthetic valve  100  can define a valve longitudinal axis  6  extending through the inflow end portion  104  and the outflow end portion  102 . In some instances, the outflow end  103  is the distal end of the prosthetic valve  100 , and the inflow end  105  is the proximal end of the prosthetic valve  100 . Alternatively, depending for example on the delivery approach of the valve, the outflow end can be the proximal end of the prosthetic valve, and the inflow end can be the distal end of the prosthetic valve. 
     The term “outflow”, as used herein, refers to a region of the prosthetic valve through which the blood flows through and out of the valve  100 , for example between the valve longitudinal axis  6  and the outflow end  103 . 
     The term “inflow”, as used herein, refers to a region of the prosthetic valve through which the blood flows into the valve  100 , for example between inflow end  105  and the valve longitudinal axis  6 . 
     The valve  100  comprises a frame  106  composed of interconnected struts  110 , and may be made of various suitable materials, such as stainless steel, cobalt-chrome alloy (e.g. MP35N alloy), or nickel titanium alloy such as Nitinol. According to some embodiments, the struts  110  are arranged in a lattice-type pattern. In the embodiment illustrated in  FIG.  2   , the struts  110  are positioned diagonally, or offset at an angle relative to, and radially offset from, the valve longitudinal axis  6 , when the valve  100  is in an expanded configuration. It will be clear that the struts  110  can be offset by other angles than those shown in  FIG.  2   , such as being oriented substantially parallel to the valve longitudinal axis  6 . 
     According to some embodiments, the struts  110  are pivotably coupled to each other. In the exemplary embodiment shown in  FIG.  2   , the end portions of the struts  110  are forming apices  132  at the outflow end  103  and apices  130  at the inflow end  105 . The struts  110  can be coupled to each other at additional junctions  128  formed between the outflow apices  132  and the inflow apices  130 . The junctions  128  can be equally spaced apart from each other, and/or from the apices  130 ,  132  along the length of each strut  110 . Frame  106  may comprise openings or apertures at the regions of apices  130 ,  132  and junctions  128  of the struts  110 . Respective hinges can be included at locations where the apertures of struts  110  overlap each other, via fasteners  134 , such as rivets or pins, which extend through the apertures. The hinges can allow the struts  110  to pivot relative to one another as the frame  106  is radially expanded or compressed. 
     In alternative embodiments, the struts are not coupled to each other via respective hinges, but are otherwise pivotable or bendable relative to each other, so as to permit frame expansion or compression. For example, the frame can be formed from a single piece of material, such as a metal tube, via various processes such as, but not limited to, laser cutting, electroforming, and/or physical vapor deposition, while retaining the ability to collapse/expand radially in the absence of hinges and like. 
     The frame  106  further comprises a plurality of cells  108 , defined between intersecting portions of struts  110 . The shape of each cell  108 , and the angle between intersecting portions of struts  110  defining the cell borders, vary during expansion or compression of the prosthetic valve  100 . Further details regarding the construction of the frame and the prosthetic valve are described in U.S. Publication Nos. 2018/0153689; 2018/0344456; 2019/0060057, all of which are incorporated herein by reference. 
     A prosthetic valve  100  further comprises one or more leaflets  136 , e.g., three leaflets, configured to regulate blood flow through the prosthetic valve  100  from the inflow end  105  to the outflow end  103 . While three leaflets  136  arranged to collapse in a tricuspid arrangement, are shown in the exemplary embodiment illustrated in  FIG.  2   , it will be clear that a prosthetic valve  100  can include any other number of leaflets  136 . The leaflets  136  are made of a flexible material, derived from biological materials (e.g., bovine pericardium or pericardium from other sources), bio-compatible synthetic materials, or other suitable materials. The leaflets may be coupled to the frame  106  via commissures  137 , either directly or attached to other structural elements connected to the frame  106  or embedded therein, such as commissure posts. Further details regarding prosthetic valves, including the manner in which leaflets may be mounted to their frames, are described in U.S. Pat. Nos. 6,730,113, 7,393,360, 7,510,575, 7,993,394 and 8,252,202, and U.S. Patent Application No. 62/614,299, all of which are incorporated herein by reference. 
     According to some embodiments, the prosthetic valve  100  may further comprise at least one skirt or sealing member, such as the inner skirt  138  shown in the exemplary embodiment illustrated in  FIG.  2   . The inner skirt  138  can be mounted on the inner surface of the frame  106 , configured to function, for example, as a sealing member to prevent or decrease perivalvular leakage. The inner skirt  138  can further function as an anchoring region for the leaflets  136  to the frame  106 , and/or function to protect the leaflets  136  against damage which may be caused by contact with the frame  106 , for example during valve crimping or during working cycles of the prosthetic valve  100 . Additionally, or alternatively, the prosthetic valve  100  can comprise an outer skirt (not shown) mounted on the outer surface of the frame  106 , configure to function, for example, as a sealing member retained between the frame  106  and the surrounding tissue of the native annulus against which the prosthetic valve  100  is mounted, thereby reducing risk of paravalvular leakage past the prosthetic valve  100 . Any of the inner skirt  138  and/or outer skirt can be made of various suitable biocompatible materials, such as, but not limited to, various synthetic materials (e.g., PET) or natural tissue (e.g. pericardial tissue). 
     According to some embodiments, a prosthetic valve  100 , which can be a mechanical prosthetic valve, comprises at least one expansion and locking assembly  140 , and preferably a plurality of expansion and locking assemblies  140 . The expansion and locking assemblies  140  are configured to facilitate expansion of the valve  100 , and in some instances, to lock the valve  100  at an expanded configuration, preventing unintentional recompression thereof, as will elaborated in greater detail hereinbelow. Although  FIG.  2    illustrates three expansion and locking assemblies  140 , mounted to the frame  106 , and optionally equally spaced from each other around an inner surface thereof, it should be clear that a different number of expansion and locking assemblies  140  may be utilized, that the expansion and locking assemblies  140  can be mounted to the frame  106  around its outer surface, and that the circumferential spacing between expansion and locking assemblies  140  can be unequal. 
       FIGS.  3 A- 3 B  illustrate three actuation assemblies  40  coupled to corresponding expansion and locking assemblies  140  attached to a bare frame  106  of the prosthetic valve  100  (without the leaflets and other components), for purposes of illustrating expansion of the prosthetic valve from the radially compressed configuration to the radially expanded configuration.  FIG.  3 A  shows the prosthetic valve  100  in a partially compressed configuration, and  FIG.  3 B  shows the prosthetic valve  100  in a fully expanded configuration. The prosthetic valve  100  in the illustrated configurations can be radially expanded by maintaining the outflow end  103  of the frame  106  at a fixed position while applying a force in the axial direction against the inflow end  105  toward the outflow end  103 . Alternatively, the prosthetic valve  100  can be expanded by applying an axial force against the outflow end  103  while maintaining the inflow end  105  at a fixed position, or by applying opposing axial forces to the outflow and inflow ends  103 ,  105 , respectively. 
       FIGS.  4 - 5 B  illustrate an expansion and locking assembly  140 , according to some embodiments.  FIG.  4    illustrates a view in perspective of an exemplary embodiment of an expansion and locking assembly  140 . The expansion and locking assembly  140  includes an outer member  142 , coupled to a component of the valve  100 , such as the frame  106 , at a first location, and an inner member  168  coupled to a component of the valve  100 , such as the frame  106 , at a second location, axially spaced from the first location. The inner member extends at least partially into the outer member, and at least one of the inner or outer member  168  or  142 , respectively, is axially movable relative to the other. 
     The inner member has an inner member first end, which can be an inner member proximal end portion, and an inner member second end, which can be an inner member distal end portion. The outer member has an outer member first end, which can be an outer member proximal end portion, and an outer member second end, which can be an outer member distal end portion. 
       FIG.  5 A  shows a view in perspective of an exemplary inner member  168 , having an inner member proximal end portion  170  and an inner member distal end portion  172 . The inner member  168  comprises an inner member fastener  174  at its distal end portion  172 , which may be formed as a rivet or a pin extending radially outward from the inner member  168 , configured to be received within respective openings or apertures of struts  110  intersecting at a junction  128  or an apex  130 ,  132 . The inner member  168  may be provided in the form of a rod having a uniform cross-section between the proximal end portion  170  and the distal end portion  172 . While an exemplary embodiment of a rod having a uniform circular cross section is illustrated, it will be clear that the cross-section can be provided with other shapes, including square, rectangular, triangular, pentagonal, hexagonal, octagonal, elliptical, star-shaped, and the like. 
       FIG.  5 B  shows the inner member  168  disposed within a lumen of the outer member  142 , and more specifically, extending through a primary channel  144  of the outer member  142 . The outer member  142  is shown with partial transparency in  FIG.  5 B  to reveal the underlying structures. The outer member  142  comprises an outer member proximal end  146  defining a proximal opening, and an outer member distal end portion  147  defining a distal opening. The outer member  142  can further comprise an outer member fastener  150  proximate to its proximal end  146 , which may be formed as a rivet or a pin extending radially outward from the external surface of the outer member  142 , configured to be received within respective openings or apertures of struts  110  intersecting at a junction  128  or an apex  132 ,  130 . 
     It will be understood that while the inner member first end and the inner member second end are exemplified throughout the figures as the inner member proximal end portion  170  and the inner member distal end portion  172 , respectively, and while the outer member first end and the outer member second end are exemplified throughout the figures as the outer member proximal end portion  146  and the outer member distal end portion  147 , respectively, in alternative configurations, the inner member first end and the inner member second end may be the inner member distal end portion  172  and the inner member proximal end portion  170 , respectively, and the outer member first end and the outer member second end may be the outer member distal end portion  147  and the outer member proximal end portion  146 , respectively. 
     The outer member  142  may further comprise a chamber  152  continuous with the primary channel  144 , such that one portion of the primary channel  144  extends between the outer member proximal end  146  and the chamber  152 , and another portion of the primary channel  144  extends between the chamber  152  and the outer member distal end portion  147 . 
     The chamber  152  comprises a proximal chamber wall  158  and a distal chamber wall  160 , and in some implementations, may be exposed to the external environment via a lateral opening  153  formed at a sidewall of the outer member  142  at the region of the chamber  158 . 
     According to some embodiments, the inner member proximal end portion  170  further comprises a threaded bore, configured to receive and threadedly engage with a threaded portion of a distal end portion  44  (shown for example in  FIGS.  7 A- 7 D ) of a corresponding actuation member  42 . 
     The expansion and locking assembly  140  can include, in some embodiments, one or more engagement surfaces configured to prevent over-expansion of the prosthetic valve  100 . For example, in the embodiment illustrated in  FIGS.  4 - 5 B , the outer member distal end portion  147  can include a bore having an outer member engagement surface  149 . The outer member engagement surface  149  can be configured to engage a corresponding inner member engagement surface  173  to prevent further proximal movement of the inner member  168  relative to the outer member  142 , so as to prevent over expansion of the prosthetic valve  100 . As shown in the illustrated embodiment, the inner member distal end portion  172  can be formed as a wider portion, relative to the remaining portion of the inner member  168  extending proximally therefrom, defining the inner member engagement surface  173  as the proximally-facing surface of the inner member distal end portion  172 . 
     As shown in  FIGS.  4  and  5 B , the outer member  142  can further comprise a recess  148  in the wall of the outer member distal end portion  147 . The recess  148  can extend through a thickness of the wall of the outer member distal end portion  147  and can extend to its distal edge. In the illustrated exemplary embodiment, the recess is substantially U-shaped, however, in other embodiments the recess can have any of various shapes. The recess  148  can be configured to limit the proximal advancement of the inner member  168  within the outer member  142 . For example, as the prosthetic valve  100  expands, the inner member  168  can slide relative to the outer member  142  until the inner member fastener  174  enters the recess  148 . The inner member  168  can continue moving relative to the outer member  142  until the inner member fastener  174  abuts a proximal edge of the recess  148 , restraining further motion of the inner member  168 . 
     Optionally, and in some embodiments preferably, the expansion and locking assembly  140  further comprises at least one plate  176  having a primary aperture  178 , wherein the at least one plate  176  is disposed around the inner member  168 , which extends through the primary aperture  178 , and is disposed within the chamber  152  of the outer member  142 . 
       FIGS.  6 A- 6 C  illustrate different optional shapes and arrangements of the at least one plate  176 . In some embodiments, the plate  176  may have a disc-like circular or elliptic shape, such as plate  176   a  illustrated in  FIG.  6 A . In other embodiments, the plate  176  may have a rectangular shape, such as plate  176   b  illustrated in  FIG.  6 B . While circular and rectangular shapes are illustrated, it will be clear that the plate  176  may have any other shape, such as a hexagon, other regular-polygon, or any irregular shape, in plan view. The at least one plate  176  typically comprises a rigid biocompatible material. In some applications, the at least one plate  176  comprises a biocompatible metal such as nitinol or stainless steel. In some applications, the at least one plate  176  comprises a plastic. 
     According to some embodiments, the at least one plate  176  comprises a plurality of plates, such as plates  176   a   a ,  176   a   b  and  176   a   c  shown in  FIG.  6 C . While three plates are illustrated in  FIG.  6 C , it will be clear that any other number of plates is contemplated, such as two plates, four plates, and so on. 
     The lateral opening  153  can extend through a thickness of a side wall of the outer member  142 , exposing at least a portion of the chamber  152 . In the illustrated embodiment, the lateral opening  153  is disposed on a side wall of the outer member  142 . However, in other embodiments, the lateral opening  153  can be disposed in any other wall of the outer member  142 . In some implementations, the opening  153  can have an elongated rectangular shape as shown in the illustrated embodiment. In other implementations, the lateral opening  153  can have any other shape, such as a circular, ovular, trapezoid and the like. Advantageously, the lateral opening  153  may assist in the process of assembling the expansion and locking assembly  140 , by providing access for insertion of the at least one plate  176  there-through into the chamber  152 . 
     According to some embodiments, a method of assembling an expansion and locking assembly  140  includes insertion of at least one plate  176  into the chamber  152  through the opening  153 . The plate  176  may be inserted in an inclined orientation, or in a substantially parallel orientation to the longitudinal axis of the outer member  142 . Once inside the chamber, the plate can be re-oriented to being substantially orthogonal to the longitudinal axis of the outer member, followed by insertion of the inner member  168  into the outer member  142 , through the primary channel  144  of the outer member  142  and through the primary aperture  178  of the at least one plate  176 . 
     The term “longitudinal axis of the outer member”, as used herein, refers to an axis which is substantially parallel to the valve longitudinal axis  6  shown in  FIG.  2   , and extends through the outer member  142 . 
       FIGS.  7 A- 7 D  show cross-sectional views, taken along line  7 - 7  of  FIG.  4   , in various stages of actuating an exemplary embodiments of an expansion and locking assembly  140  to facilitate valve expansion, and potentially lock the valve it in an expanded configuration.  FIG.  7 A  shows an initial state in which the actuation member distal end portion  44  is threaded into a threaded bore of the inner member proximal end portion  170 . The inner member  168  extends through the primary channel  144  and the chamber  152  of the outer member  142 , such that the inner member fastener  174  is distanced from the outer member fastener  150  at a distance that may be associated with a compressed, or a partially compressed, configuration of the valve  100 . In this state, the inner member  168  may extend distally from the outer member  142  such that the inner member fastener  174  is distanced distally away from the outer member distal end  147 . 
     While the outer member fastener  150  and the inner member fastener  174  are not visible in  FIGS.  7 A- 7 D , the illustrated configurations show the relative position of the inner member  168  and the outer member  142  when the outer member proximal end  146  is coupled, for example via the outer member fastener  150 , to the frame  106  at a first location, and the inner member distal end portion  172  is coupled, for example via the inner member fastener  174 , to the frame  106  at a second location. 
     According to some embodiments, the first location can be positioned at an outflow end portion  102 , and the second location can be positioned at the inflow end portion  104 . In the embodiment illustrated in  FIGS.  2 - 3 B , the outer member  142  is secured to an outflow apex  132  via outer member fastener  150 , and the inner member  168  is secured to an inflow apex  130  via inner member fastener  174 . In some applications, the outer members  142  may further serve as commissure posts to which commissures  137  may be attached (see  FIG.  2   ). 
     The chamber  152  may be generally divided into a first zone  154  and a second zone  156 , defined as two opposite zones or volumes from both sides of the inner member  168 , such that each of the first and second zones  154  and  156 , respectively, is defined between the inner member  168  and an opposite inner sidewall of the chamber  152 . For example, the second zone  156  may be defined as the space volume between the inner member  168  and the lateral opening  153  (if present), while the first zone  154  may be defined as the space volume between the inner member  168  and the chamber wall opposite to the lateral opening ( 153 ). In some implementations, the distal chamber wall  160  may comprise a distal wall first side  162 , defined as the portion of the distal chamber wall  164  disposed within the first zone ( 154 ), and a distal wall second side  164 , defined as the portion of the distal chamber wall  164  disposed within the second zone ( 156 ). 
     According to some embodiments, the distal chamber wall  160  comprises at least one angled portion, defined as a portion which is angled relative to a longitudinal axis of the inner member  168 .  FIGS.  5 B and  7 A- 7 D  illustrate an embodiment of an outer member  142   a  comprising a distal wall first side  162   a  which is angled at proximally-oriented acute angle, relative to a longitudinal axis of the inner member  168 . 
     While the distal chamber wall  160   a  is illustrated as having a step-like configuration, wherein the distal wall first side  162   a  is angled and the distal wall second side  164   a  is substantially orthogonal relative to the longitudinal axis of the inner member  168 , it will be clear that in other configurations, the distal wall second side may be continuous with the distal wall first side, such that the entire distal chamber wall may be angled relative to the longitudinal axis of the inner member  168 . 
     The term “longitudinal axis of the inner member”, as used herein, refers to an axis which is substantially parallel to the valve longitudinal axis  6  shown in  FIG.  2   , and extends through the inner member  168 . 
     The plate  176  may also include a plate first side  180  and an opposite plate second side  183 , wherein the plate first side  180  is defined as the portion of the plate  176  residing within the first zone  154  of the chamber  152 , between the primary aperture  178  and a plate first end  181 , and the plate second side  182  is defined as the portion of the plate  176  residing within the second zone  156  of the chamber  152 , between the primary aperture  178  and a plate second end  183 . 
     As mentioned with respect to the configuration shown in  FIG.  7 A , the actuation member distal end portion  44  is threadedly engaged with the threaded bore at the inner member proximal end portion  170 . According to some embodiments, as shown in  FIGS.  7 A- 7 D , the actuation member distal end portion  44  includes external threads, configured to engage with internal threads of a proximal bore of the inner member proximal end portion  170 . According to alternative embodiments, an inner member may include a proximal extension provided with external threads, configured to be received in and engage with internal threads of a distal bore formed within the actuation member (embodiments not shown). 
     The actuation support sleeve  46  surrounds the actuation member  42  and may be connected to the handle  30 . The actuation support sleeve  46  and the outer member  142  are sized such that the distal lip of the actuation support sleeve  46  can abut or engage the outer member proximal end  146 , such that the outer member  142  is prevented from moving proximally beyond the actuation support sleeve  46 . 
     In order to radially expand the frame  106 , and therefore the valve  100 , the actuation support sleeve  46  can be held firmly against the outer member  142 . The actuation member  42  can then be pulled in a first direction, such as a proximally oriented direction  2 , as shown in  FIG.  7 A . Since the actuation support sleeve  46  is being held against the outer member  142 , which is connected, in the exemplary embodiment, to an outflow apex  132 , the outflow end  103  of the frame  106  is prevented from moving relative to the actuation support sleeve  46 . As such, movement of the actuation member  42  in the first direction, which is shown to be in the illustrated non-binding example as the proximally oriented direction  2 , can cause movement of the inner member  168  in the same direction, thereby causing the frame  106  to foreshorten axially and expand radially. 
     More specifically, as shown for example in  FIG.  3 A , the inner member fastener  174  extends through openings in two struts  110  interconnected at an inflow apex  130 , while the outer member fastener  150  extends through openings in two struts  110  interconnected at an outflow apex  132 . As such, when the inner member  168  is moved axially, for example in a proximally oriented direction  2 , within the outer member  142 , the inner member fastener  174  moves along with the inner member  168 , thereby causing the portion to which the inner member fastener  174  is attached to move axially as well, which in turn causes the frame  106  to foreshorten axially and expand radially. 
     The struts  110  to which the inner member fastener  174  is connected, are free to pivot relative to the inner member fastener  174  and to one another as the frame  106  is expanded or compressed. In this manner, the inner member fastener  174  serves as a coupling means that forms a pivotable connection between those struts  110 . Similarly, struts  110  to which the outer member fastener  150  is connected, are also free to pivot relative to the outer member fastener  150  and to one another as the frame  106  is expanded or compressed. In this manner, the outer member fastener  150  also serves as a coupling means that forms a pivotable connection between those struts  110 . 
     According to some embodiments, the diameter of the primary aperture  178  of the plate  176  is closely matched with the outer diameter of the inner member  168  extending therethrough, such that axial movement of the inner member  168  may frictionally engage with the boundaries of the primary aperture  178  and facilitate axial translation of the plate  176  there-along. In some embodiments, the diameter of the primary aperture is no more than 10 percent larger than the diameter of the inner member  168  at the portion extending therethrough. In some embodiments, the diameter of the primary aperture is no more than 5 percent larger than the diameter of the inner member  168  at the portion extending therethrough. 
     Pulling the inner member  168  in a proximally oriented direction  2  (which may serve as the first directions, as shown in  FIG.  7 A ) may pull the plate  176  along with the inner member  168 , optionally (but not necessarily) until plate  176  is pressed against the proximal chamber wall  158 . In some implementations, the proximal chamber wall, or at least a portion thereof, is substantially orthogonal to the longitudinal axis of the inner member, such that when the plate  176  is pressed there-against, the plate  176  also assumes an orientation which is substantially orthogonally to the longitudinal axis of the inner member. In this position, the inner member  168  may be further pulled in a proximal direction  2 , slidably moving through the plate  176 , which may remain pressed against the proximal surface of the proximal chamber wall  158 . 
       FIG.  7 B  shows an optional stage in which proximally oriented force is no longer applied by the actuation assembly  40  on the expansion and locking assembly  140 , which may occur in a partially expanded configuration of the valve  100 . Any attempt aimed at valve re-compression will require distancing the proximal and distal junctions away from each other, for example by moving the inner member  168  in a second direction, such as a distally oriented direction  4 , within the outer member  142 . Such attempted movement of the inner member  168  in a distal direction may result in axial translation of the plate  176  therewith, for example toward the distal chamber wall  160 . 
     The at least one plate  176  is configured to transition between an angled locking orientation, and a non-locking orientation. Specifically, since the distal wall first side  162  is angled, when the plate first side  180  is pressed there-against—the entire plate  176  assumes an angled locking orientation relative to the longitudinal axis of the inner member  168 . Generally, in some implementation, the distal wall first side  162  includes at least one point of contact configured to contact the plate  176 , which is proximal relative to any region of the distal wall second side  164  between the primary aperture  178  and the plate second end  183 . In this manner, when the plate  176  is pushed in the distal direction to contact the distal chamber wall  160 , it assumes an angled locking orientation such that the plate first end  181  is more proximal than the plate second end  183 . 
     Once the plate contacts the distal chamber wall  160 , it is tilted to an angled orientation over the inner member  168  until it reaches a self-friction lock angle, inhibiting further advancement of the inner member  168  in the second direction (e.g., the distal direction), which is defined as the angled locking orientation. Thus, the proposed mechanism enables a one-directional axial movement of the inner member  168  in the first direction (e.g., the proximal direction) for valve expansion, while the self-friction lock angle of the at least one plate  176  is configured to lock the valve in the expanded or partially expanded diameter, and prevent unintentional re-compression. 
     For the sake of simplicity, the first direction will be described in the following exemplary embodiments as the proximally oriented directions  2 , and the second direction will be described as the distally oriented direction  4 , though in alternative implementations, the expansion and locking assemblies may be designed to operate in reverse, such that the first direction will be the distally oriented direction  4 , and the second direction will be the proximally oriented direction  2 , mutatis mutandis. 
     As shown in  FIG.  7 C , the angled locking orientation of the at least one plate  176  over the inner member  168 , prevents movement of the inner member  168  only in the distal direction  4 , while further valve expansion is enabled by further pulling the inner member  168  relative to the outer member  142  in the proximal direction  2 , for example via the actuation assembly  40  in a similar manner to that described in conjunction with  FIG.  7 A . When the inner member  168  is pulled in a proximal direction, the at least one plate  176  may transition to a non-locking orientation, which allows free axial movement of the inner member  168  through the primary aperture  178 . The non-locking orientation may be either a substantially orthogonal orientation of the at least one plate  176  relative to the longitudinal axis of the inner member, or any other angled orientation of the at least one plate  176  relative to the inner member  168  at an angle which is between the self-friction lock angle and an obtuse angle with respect to the longitudinal axis of the inner member, and may thus allow axial movement of the inner member  168  there-through. 
     While the plate  176  is shown in  FIGS.  7 A and  7 C  pressed against the proximal chamber wall  158 , for example due to frictional forces formed between the inner wall of the primary aperture  178  and the outer surface of the inner member  168 , it will be clear that in practice this may not necessarily be the case, and that the plate  176  may be otherwise positioned elsewhere between the proximal chamber wall  158  and the distal chamber wall  160 , oriented in either a substantially orthogonal orientation relative to the inner member  168 , or angled relative thereto in another orientation which is not the angle-locking orientation. For example, the plate  176  can be angled at any angle between the angle-locking orientation shown in  FIG.  7 B  and the orthogonal orientation shown in  FIG.  7 A , as long as such orientation of the plate  176  allows the inner member  168  to translate axially, for example in the proximally oriented direction  2 , through the primary aperture  178 . 
       FIG.  7 D  shows the inner member  168  positioned at a more proximal position relative to its position within the outer member  142  shown in  FIGS.  7 A- 7 B , which may represent a fully expanded configuration of the valve in  FIG.  7 D . In the illustrated state, pulling force in the proximal direction is no longer applied to the inner member  168 . When an external force (e.g., applied by the surrounding anatomy) strives to re-compress the valve ( 100 ), thereby distancing the proximal and distal junctions away from each other, the plate  176  may be once again pushed against the distal chamber wall  160 , assuming an angled locking orientation which serves to lock the expansion and locking assembly  140  and retain the valve  100  in the expanded configuration. 
     Once the desired diameter of the prosthetic valve  100  is reached, the actuation member  42  may be rotated about its axis to unscrew the actuation member  42  from the inner member  168 , as shown in  FIG.  7 D . This rotation serves to disengage the threaded actuation member distal end portion  44  from the threaded bore of the inner member proximal end portion  170 , enabling the actuation assemblies  40  to be pulled away, and retracted, together with the delivery apparatus  12 , from the patient&#39;s body, leaving the prosthetic valve ( 100 ) implanted in the patient. 
     The patient&#39;s native anatomy, such as the native aortic annulus in the case of transcatheter aortic valve implantation, may exert radial forces against the prosthetic valve  100  that would strive to compress it. However, the self-friction lock angle assumed by the plate  176  in the angled locking orientation, causes the inner borders of the primary aperture to press against and/or frictionally engage with the outer surface of the inner member  168 , so as to prevent such forces from compressing the frame  106 , thereby ensuring that the frame  106  remains locked in the desired radially expanded configuration. 
     Thus, the prosthetic valve  100  is radially expandable from the radially compressed configuration shown in  FIG.  7 A  to the radially expanded configuration shown in  FIG.  7 D , upon actuation of the actuator assemblies  40 , wherein such actuation includes approximating the second locations (e.g., inflow apices  130 ) to the first locations (e.g., outflow apices  132 ) of the valve. The prosthetic valve  100  is further releasable from the delivery apparatus  12  by decoupling each of the actuation members  42  from each corresponding expansion and locking assembly  140  that was attached thereto. 
     The terms coupled, engaged, connected and attached, as used herein, are interchangeable. Similarly, the term decoupled, disengaged, disconnected and detached, as used herein, are interchangeable. 
     According to some embodiments, as illustrated, the angled portion of the distal chamber wall  160 , e.g. the distal wall first side  162 , is oriented at an angle which is more acute, with respect to the longitudinal axis of the inner member ( 168 ), relative to the self-friction lock angle, formed between the plate  176  and the longitudinal axis of the inner member ( 168 ) at the angled locking orientation. In such embodiments, the plate first end  181  may contact the distal wall first side  162  in the angled locking orientation, while the remainder of the plate  176  may remain offset from the distal chamber wall  160 . In alternative implementations, the angled portion of the distal chamber wall  160  may be angled at an angle which is substantially equal to the self-friction lock angle, such that a larger portion of the plate  176 , e.g. the complete distal surface of the plate first side  180 , may contact the distal wall first side  162  in the angled locking orientation. 
     It is to be understood that any reference to angles throughout the current disclosure, refers to angles facing the first direction, i.e., angled facing the proximal direction  2  in the illustrated embodiments. 
     While the inner member  168  and the outer member  142  are shown in the illustrated embodiment of  FIGS.  2 - 3 B  connected to an inflow apex  130  and an outflow apex  132 , respectively, it should be understood that they can be connected to other junctions  128  of the frame  106 . For example, the inner member fastener  174  can extend through openings formed in interconnected struts at a junction  128  at the inflow end portion  104 , proximal to the inflow apices  130 . Similarly, the outer member fastener  150  can extend through openings formed in interconnected struts at a junction  128  at the outflow end portion  102 , distal to the outflow apices  132 . 
     While the frame is shown in the illustrated examples to expand radially outward by axially moving the inner member  168  in a proximally oriented direction  2 , relative to the outer member  142 , it will be understood that similar frame expansion may be achieved by axially pushing an outer member  142  in a distally oriented direction, relative to an inner member  168 . Moreover, while the illustrated embodiments in  FIGS.  2 - 3 B  show the outer member  142  affixed to an outflow end portion  102  of the frame  106 , and an inner member  168  affixed to an inflow end portion  104  of the frame  106 , in alternative embodiments, the outer member  142  may be affixed to the inflow end portion  104  of the frame  106 , while the inner member  168  may be affixed to the outflow end portion  102  of the frame  106 . 
     According to some embodiments, the inner surface of the primary aperture  178  of the plate  176 , and/or the outer surface of the inner member  168  extending through the primary aperture  178 , further comprises a texture and/or friction-enhancement features (not shown), configured to promote or enhance frictional engagement there-between. 
     The outer member  142  in the illustrated embodiments is shown to have a rectangular shape in cross-section, and the inner member  168  is shown to have a circular shape in cross-section corresponding to the shape of the primary channel  144 . As shown in  FIGS.  2 - 3 A , a rectangular cross-section of the outer members  142  can advantageously minimize the distance that the expansion and locking assemblies extend into the lumen of the frame  106 , which can reduce the overall crimp profile of the valve  100 . However, in other embodiments the outer member  142  and/or the inner member  168  can have any of various corresponding shapes in cross-section, for example, circular, ovular, triangular, rectangular, square, or combinations thereof. 
     According to some embodiments, the handle  30  can comprise control mechanisms which may include steerable or rotatable knobs  32 , levers, buttons and such, which in some implementation may be manually controllable by an operator to produce axial and/or rotatable movement of different components of the delivery apparatus  12 . For example, the embodiment of handle  30   a  illustrated in  FIG.  1    comprises first, second, third and fourth knobs  32   a   a ,  32   a   b ,  32   a   c  and  32   a   d , respectively. 
     Knob  32   a   a , shown in  FIG.  1   , can be a rotatable knob configured to produce bi-directional axial translation of the outer shaft  20  relative to the prosthetic valve  100  in the distal and/or proximal directions, for example to retract the outer shaft  20  and expose the prosthetic valve  100  once it is positioned at or adjacent the desired site of implantation within the patient&#39;s body. For example, rotation of the knob  32   a   a  in a first direction (e.g., clockwise) can retract the outer shaft  20  proximally relative to the prosthetic valve  100 , and rotation of the knob  32   a   a  in a second direction (e.g., counterclockwise) can advance the outer shaft  20  distally. 
     Knob  32   a   b , shown in  FIG.  1   , can be a rotatable knob configured to steer the outer shaft  20  as it advances through the curvatures of the patient&#39;s vasculature. Particularly, the handle  30  may comprise, in some embodiments, a steering mechanism, which may include at least one pull wire (not shown) attached at its distal end to the outer shaft  20  (or other shafts of the delivery apparatus  12 ), such that rotation of the knob  32   a   b  may vary the tension of the pull wire, which is effective to vary the curvature of the outer shaft  20 . 
     Knob  32   a   d , shown in  FIG.  1   , can be a rotatable knob configured to produce radial expansion and/or contraction of the prosthetic valve  100 . For example, rotation of the knob  32   a   d  can move the actuation member  42  and the actuation support sleeve  46  axially relative to one another. Rotation of the knob  32   a   d  in a first direction (e.g., clockwise) can radially expand the prosthetic valve  100 , and rotation of the knob  32   a   d  in a second direction (e.g., counterclockwise) can radially contract or re-compress the prosthetic valve  100 . 
     Knob  32   a   c , shown in  FIG.  1   , can be a rotatable knob configured to release the prosthetic valve  100  from the delivery apparatus  12 . For example, rotation of the knob  32   a   c  in a first direction (e.g., clockwise) can disengage the actuation assemblies  40  from the expansion and locking assemblies  140  of the prosthetic valve  100 . 
     The handle  30  may include more or less than the four knobs  32  described herein above, configured to fulfill only some of the functionalities described for knobs  32   a ,  32   b ,  32   c  and  32   d , and/or additional functionalities. Any of the knobs  32   a ,  32   b ,  32   c  and  32   d  may be implemented, in alternative embodiments, as other types of buttons, levers, knobs and the like, such as push/pull knobs which may be actuated by sliding or moving the knobs axially. 
     According to other embodiments, control mechanisms in the handle  30  and/or other components of the delivery apparatus  12  can be electrically, pneumatically and/or hydraulically controlled. According to some embodiments, the handle  30  can house one or more electric motors which can be actuated by an operator, such as by pressing a button or a switch on the handle  30 , to produce movement of components of the delivery apparatus  12 . For example, the handle  30  may include one or more motors operable to produce linear movement of components of the actuation assemblies  40 , and/or one or more motors operable to produce rotational movement of the actuation members  42  to disconnect the threaded actuation member distal end portion  44  from the inner member proximal end portion  170 . According to some embodiments, one or more manual or electric control mechanism is configured to produce simultaneous linear and/or rotational movement of all of the actuation members  42 . 
     Optionally, but in some embodiments preferably, the expansion and locking assembly  140  further comprises at least one spring  186  disposed within the chamber  152 , configured to urge the at least one plate  176  in a second direction so as to assume an angled locking orientation, for example by urging it against the distal chamber wall  160 . The spring constant may be chosen to exert a force sufficient to press the at least one plate  176  against the distal chamber wall  160  in the absence of an external proximally oriented force applied to the at least one plate  176 , resulting in a transition of the at least one plate  176  to the angled locking orientation, and to allow transition of the at least one plate  176  to a non-locking orientation upon application of an external proximally oriented force either directly to the plate  176 , or indirectly by pulling the inner member  168  in the proximal direction, for example via the actuation assembly  40 . 
     For sake of simplicity, the term “plate”, as used throughout the current specification, may refer to either a single plate (as shown, for example, in  FIGS.  6 A- 6 B ), or a plurality of plates (as shown, for example, in  FIG.  6 C ). 
     The spring  186  may be disposed between the plate  176  and either one of: the proximal chamber wall  158  or the distal chamber wall  160 . According to some embodiments, the spring  186  is a helical spring.  FIGS.  8 A- 8 C  show various exemplary types and arrangements of a helical spring  186 .  FIG.  8 A  shows an exemplary embodiment of a helical spring  186   a  coiled around the inner member  168 , such that the inner member  168  extends through the coils of the spring  186   a . The spring  186   a  shown in  FIG.  8 A  is a compression spring disposed between the proximal chamber wall  158  and the plate  176 , and may be affixed to either the proximal chamber wall  158  and/or the plate  176 , configured to push the plate  176  toward the distal chamber wall  160 , so as to orient it in the illustrated angled locking orientation. 
       FIG.  8 B  shows an exemplary embodiment of a helical spring  186   b  adjacent the inner member  168 . The spring  186   b  shown in  FIG.  8 B  is a compression spring disposed between the proximal chamber wall  158  and the plate  176 , and more specifically, disposed within the first zone  154  between the proximal chamber wall  158  and the plate first side  180 , and may be affixed to either the proximal chamber wall  158  and/or the plate  176  (for example, to the plate first side  180 ), configured to push the plate  176  toward the distal chamber wall  160 , so as to orient it in the illustrated angled locking orientation. 
       FIG.  8 C  shows another exemplary embodiment of a helical spring  186   c  adjacent the inner member  168 . The spring  186   c  shown in  FIG.  8 C  is an extension spring disposed between the distal chamber wall  160  and the plate  176 , and more specifically, disposed within the second zone  156  between the distal wall second side  164  and the plate second side  182 , and may be affixed to either the distal chamber wall  160  (for example, to the distal wall second side  164 ) and/or the plate  176  (for example, to the plate second side  182 ), configured to pull the plate  176  toward the distal chamber wall  160 , so as to orient it in the illustrated angled locking orientation. The proximal end of the spring  186   c  may be coupled to the plate  176  (for example, to the plate second side  182 ), and the distal end of the spring may be coupled to the distal chamber wall  160  (for example, to the distal wall second side  164 ). 
     It will be clear that the embodiments illustrated in  FIGS.  8 A- 8 C  are merely exemplary, and that other arrangements and embodiments are contemplated, such as a helical spring  186  coiled around the inner member  168 , in a similar manner to that shown in  FIG.  8 A , but implemented as an extension spring disposed between the distal chamber wall  160  and the plate  176 , configured to pull the plate  176  toward the distal chamber wall  160 . 
     According to some embodiments, the spring  186  is a leaf spring.  FIGS.  9 A- 9 B  shows a leaf spring  186   d  disposed between the proximal chamber wall  158  and the plate  176 .  FIG.  9 A  shows the plate  176  in a non-locking orientation, for example during application of a proximally oriented pull-force on the inner member  168 , while  FIG.  9 B  shows the plate  176  pushed by the leaf spring  186   d  toward the distal chamber wall  160 , so as to orient it in the illustrated angled locking orientation. The leaf spring  186   d  may be attached, at its proximal end, to the proximal chamber wall  158 . 
     While  FIGS.  9 A- 9 B  illustrate an embodiment of the leaf spring  186   d  configured to contact the plate first side  180  to urge it toward the distal wall first side  162 , other embodiments are contemplated, such as a leaf spring provided with an aperture through which the inner member  168  can extend, configured to contact portions of the plate  176  that may be in the vicinity of the primary aperture  178 , so as to urge it toward the distal chamber wall  160  (embodiments not shown). 
     According to some embodiments, the plate  176  is coupled to a wall of the chamber  158  via a plate hinge  184 , configured to pivot about the hinge  184  between the non-locking orientation and the angled locking orientation.  FIGS.  10 A- 10 B  show a plate  176   c , coupled to the proximal chamber wall  158   b  of the outer member  142   b  at a plate hinge  184 . Optionally, a spring  186  may be added to urge the plate  176   c  toward the distal chamber wall  160 . 
       FIG.  10 A  shows the plate  176   c  in a non-locking orientation, for example during application of a proximally oriented pull-force on the inner member  168 , while  FIG.  10 B  shows the plate second side  182   c  pulled in the distal direction  4  by a spring  186   c  (similar to the arrangement illustrated and described in conjunction with  FIG.  8 C ), thereby pivoting the plate  176   c  about the hinge  184  to the angled locking orientation. 
     As shown in  FIGS.  10 A- 10 B , when a plate  176   c  is attached to a wall of the chamber  152  via a plate hinge  184 , the distal chamber wall  160  does not necessarily need to include a feature configured to orient the plate  176   c  in the angle locking orientation. For example, the distal chamber wall  160   c  illustrated in  FIGS.  10 A- 10 B  does not include any angled portions, since the plate  176   c  does not even need to contact the distal chamber wall  160   c  at any point to transition to the angled locking orientation of  FIG.  10 B . In fact, in some implementations, the chamber may include a proximal chamber wall, but may be open ended in the distal direction, without any distal chamber wall. 
     According to some embodiments, the distal chamber wall  160  may include features other than an inclined distal wall first side  162 , configured to transition the plate  176  in the angled locking position when pressed there-against, such as a proximally oriented protrusion  166  extending proximally from the distal wall second side  164 .  FIG.  11    shows an embodiments of an outer member  142   c  comprising a proximally oriented protrusion  166   c  extending from the distal chamber wall  160   d , and more specifically, from the distal wall first side  162   c . Optionally, a spring  186  may be added to urge the plate  176   c  toward the distal chamber wall  160 . 
     As shown in  FIG.  11   , when the plate  176 , and more specifically, the plate first side  180 , is pressed against the proximally oriented protrusion  166   c , the plate  176  transitions to the angled locking orientation, optionally by the plate second side  182  being pulled in the distal direction  4  by a spring  186   c  (similar to the arrangement illustrated and described in conjunction with  FIG.  8 C ). 
       FIGS.  12 A- 12 B  show cross-sectional views of different phases during and after actuation of an actuating the expansion and locking assembly which comprises a plurality of plates  176 , such as three plates  176   a ,  176   b  and  176   c , instead of a single plate  176  shown for example in  FIGS.  7 A- 7 D . In the actuation state shown in  FIG.  12 A , the actuation member distal end portion  44  is threadedly engaged with the threaded bore at the inner member proximal end portion  170 . The actuation member  42  may be pulled in a proximally oriented direction  2 , while the actuation support sleeve  46  is held firmly against the outer member  142  so as to prevent the outflow end  103  of the frame  106  from moving relative to the actuation support sleeve  46 . As such, movement of the actuation member  42  in a proximally oriented direction  2  causes movement of the inner member  168  in the same direction, thereby causing the frame  106  to foreshorten axially and expand radially. 
     Pulling the inner member  168  in a proximally oriented direction  2  (as shown in  FIG.  12 A ) may pull at least one of the plurality of plates  176 , and potentially all of the plurality of plates  176 , along with the inner member  168 , optionally (but not necessarily) until at least the most proximal plate  176  is pressed against the proximal chamber wall  158 . 
       FIG.  12 B  shows the inner member  168  positioned at a more proximal position relative to its position within the outer member  142  shown in  FIG.  12 A . In the illustrated state, pulling force in the proximal direction is no longer applied to the inner member  168 . When an external force (e.g., applied by the surrounding anatomy) strives to re-compress the valve ( 100 ), thereby distancing the proximal and distal junctions away from each other, at least one of the plurality of plates  176 , and potentially all of the plates  176 , are pushed against the distal chamber wall  160 , assuming an angled locking orientation which serves to lock the expansion and locking assembly and retain the valve ( 100 ) in the expanded configuration. Thereafter, the actuation member  42  may be rotated about its axis to unscrew it from the inner member  168 , enabling the actuation assemblies  40  to be pulled away and retracted, together with the delivery apparatus  12 , from the patient&#39;s body, leaving the prosthetic valve ( 100 ) implanted in the patient. 
     Advantageously, a plurality of plates  176 , comprised within a single chamber  152 , may provide several points of contact between the inner boundaries of the corresponding primary aperture  178  and the inner member  168  in the angled locking state of the plates  176 , thereby providing a higher friction-force there-between to improve reliability of the locked state of the expansion and locking assemblies. While three plates  176   a ,  176   b  and  176   c  are shown in  FIGS.  12 A- 12 B , it will be clear that any other number of plates is contemplated. Moreover, the plurality of plates  176  can be of any type disclosed herein, such as a plurality of disc-like circular or oval-shaped plates  176   a  shown in  FIG.  6 C , a plurality of rectangularly shaped plates  176   b , or any other type of plates. 
     Prior to implantation, the prosthetic valve  100  can be crimped onto the delivery apparatus  12 . This step can include placement of the radially compressed valve  100  within the outer shaft  20 . Once delivered to the site of implantation, such as a native annulus, the valve  100  can be radially expanded within the annulus, for example, by the expansion and locking assemblies  140  in the manner described herein above. However, during such implantation procedures, it may become desirable to re-compress the prosthetic valve  100  in situ in order to reposition it. Valve re-compression may be achievable only if the inner members  168  are allowed to axially translate in a distally oriented direction  4  (i.e., in the second direction), relative to the outer members  142 , which in turn can occur only if the plates  176  are released from the angled locking orientations to the non-locking orientations. 
     According to some embodiments, the delivery assembly comprises at least one release assembly  50 , and preferably a plurality release assemblies  50 , detachably attached to corresponding release members  188  extending through the outer members  142  of expansion and locking assemblies  140 , and configured to transition the plates  176  from an angled locking orientation to a non-locking orientation, so as to allow re-compression of the prosthetic valve  100 . 
       FIG.  13    shows a view in perspective of a delivery assembly  10   b , which is similar to the delivery assembly  10   a  shown in  FIG.  1   , except that it further comprises a plurality of release assemblies  50 . The prosthetic valve  100  can be on or releasably coupled to the delivery apparatus  12   b , which can include a handle  30   b  at a proximal end thereof, a delivery shaft  22  extending therefrom, and optionally an outer shaft  20  extending over the delivery shaft  22 . The delivery apparatus  12   b  can further include a nosecone  26  attached to the distal end of the nosecone shaft  24 , which are removed from view in  FIG.  13    for clarity. 
     As further shown in  FIG.  13   , the delivery apparatus  12   b  further comprises a plurality of actuation assemblies  40  and a plurality of adjacent release assemblies  50 , extending from the handle  30   a  through the delivery shaft  22 . In the illustrated exemplary embodiment, the prosthetic valve  100  has three actuation assemblies  40  and three adjacent release assemblies  50 , however, in other embodiments a greater or fewer number of actuation assemblies  40  and/or release assemblies  50  can be used. 
     Each release assembly  50  can generally include a release arm  52  (hidden from view in  FIG.  13   , but visible for example in  FIGS.  16 A- 16 D ) releasably coupled at its distal end  54  to respective expansion and locking assembly  140  of the valve  100 , and a release support sleeve  56  disposed around the corresponding release arm  52 . The release arm  52  and the release support sleeve  56  can be movable longitudinally relative to each other in a telescoping manner. The release arms  52  can include, for example, wires, cables, rods, or tubes. The release support sleeves  56  can include, for example, tubes or sheaths having sufficient rigidity such that they can apply a distally directed force to the frame without bending or buckling. 
     The proximal ends of the delivery shaft  22 , components of the actuation assemblies  40 , components of the release assemblies  50 , and when present—the outer shaft  20 , can be coupled to the handle  30   b . During delivery of the prosthetic valve  100 , the handle  30   b  can be maneuvered by an operator (e.g., a clinician or a surgeon) to axially advance or retract components of the delivery apparatus  12   b , such as the delivery shaft  22  and/or the outer shaft  20 , through the patient&#39;s vasculature, as well as to expand or contract the prosthetic valve  100 , for example by maneuvering the actuation assemblies  40  and/or the release assemblies  50 , and to disconnect the prosthetic valve  100  from the delivery apparatus  12 , for example—by decoupling the actuation members  42  and the release arms  52  from the expansion and locking assemblies  140  of the valve  100 , in order to retract it once the prosthetic valve  100  is mounted in the implantation site. 
     According to some embodiments, the delivery apparatus  12   b  further comprises a re-compression mechanism (not shown), configured to facilitate re-compression of the prosthetic valve  100  upon expansion thereof. Further details regarding various configurations and types of prosthetic valve re-compression mechanisms can be found, for example, in International Application Publication No. WO 2020/081893, and U.S. application No. 62/928,320, both of which are incorporated herein by reference. 
       FIG.  14    shows the valve  100  (without the leaflets and other components) in a radially expanded configuration, equipped with three expansion and locking assemblies  140  coupled to corresponding actuation assemblies  40  and to release assemblies  50 . As shown, each expansion and locking assemblies  140  can be releasably coupled to a single actuation assembly  40 , and to a single release assembly  50  adjacent the actuation assembly  40 . 
       FIG.  15 A- 15 B  illustrate an expansion and locking assembly  140   d , which can be similar to any of the previous embodiments disclosed herein above for expansion and locking assemblies  140 , further comprising a release member  188  at least partially extending into the expansion and locking assembly  140   d . Optionally, but in some embodiments preferably, the outer member  142   d  further comprises a release channel  145 , configured to accommodate the release member  188  therein. 
     According to some embodiments, the plate  176   d  comprises a primary aperture  178   d  and a release aperture  179 .  FIG.  15 A  shows a view in perspective of an inner member  168  extending through the primary aperture  178   d , and an exemplary release member  188  extending through the release aperture  179 . The release member  188  comprises a release member proximal end portion  190  and a release member distal end portion  192 , terminating at a release member distal end  193  (shown, for example, in  FIG.  17 A ). The release member  188  may be provided in the form of a rod having a uniform cross-sectional profile along its length. While an exemplary embodiment of a rod having a uniform circular cross section is illustrated, it will be clear that the cross-section can be provided with other shapes, including square, rectangular, triangular, pentagonal, hexagonal, octagonal, elliptical, star-shaped, and the like. 
       FIG.  15 B  shows both the inner member  168  and the release member  188  disposed within lumens of the outer member  142   d , and more specifically, extending through a primary channel  144   d  and a release channel  145 , respectively, of the outer member  142   d . The outer member  142   d  is shown with partial transparency in  FIG.  15 B  to reveal the underlying structures. The outer member  142   d  comprises an outer member proximal end  146   d  defining two proximal openings for the primary channel  144   d  and a release channel  145 , and an outer member distal end portion  147   d  defining a distal opening for the inner member  168 . As shown, the release channel  145  extends between the outer member proximal end  146   d  and the chamber  152   d , enabling the release member  188  to extend there-through, into the chamber  152   d . 
     According to some embodiments, the release member proximal end portion  190  further comprises a threaded bore, configured to receive and threadedly engage with a threaded portion of a distal end portion  54  (shown for example in  FIGS.  16 A- 16 D ) of a corresponding release arm  52 . 
       FIGS.  16 A- 16 D  show cross-sectional views in various stages of actuating the expansion and locking assembly  140   d  to facilitate valve expansion and lock the valve it in an expanded configuration, as well as to allow re-compression of a locked valve.  FIG.  16 A  shows an initial state in which the actuation member distal end portion  44  is threaded into a threaded bore of the inner member proximal end portion  170 , and the release arm distal end portion  54  is threaded into a threaded bore of the release member proximal end portion  190 . The inner member  168  extends through the primary channel  144   d  and the chamber  152   d  of the outer member  142   d , such that the inner member fastener ( 174 ) is distanced from the outer member fastener ( 150   d ) at a distance that may be associated with a compressed, or a partially compressed, configuration of the valve ( 100 ). In this state, the inner member  168  may extend distally from the outer member  142   d  such that the inner member fastener ( 174 ) is distanced distally away from the outer member distal end  147   d . The release member  188  extends through the release channel  145   d , and may partially extend into the chamber  152   d , wherein the release member distal end portion  192  is coupled to the plate  176 . 
     According to some embodiments, as shown in  FIGS.  16 A- 16 D , the release arm distal end portion  54  includes external threads, configured to engage with internal threads of a proximal bore of the release member proximal end portion  190 . According to alternative embodiments, a release member may include a proximal extension provided with external threads, configured to be received in and engage with internal threads of a distal bore formed within the release arm (embodiments not shown). 
     In the actuation state shown in  FIG.  16 A , the actuation member  42  may be pulled in a proximally oriented direction  2 , while the actuation support sleeve  46  is held firmly against the outer member  142   d  so as to prevent the outflow end  103  of the frame  106  from moving relative to the actuation support sleeve  46 . As such, movement of the actuation member  42  in a proximally oriented direction  2  causes movement of the inner member  168  in the same direction, thereby causing the frame  106  to foreshorten axially and expand radially. Pulling the inner member  168  in a proximally oriented direction  2  (as shown in  FIG.  16 A ) may pull the plate  176   d  there-along, optionally (but not necessarily) until the plate  176   d  is pressed against the proximal chamber wall  158   d . 
     In some implementations, the release arm  52  may be pulled in the proximal direction  2 , simultaneously with the pulling of the actuation member  42 , thereby pulling the release member  188  therewith in the proximal direction  2 . Alternatively, the release arm  52  may remain free or even pushed in the distal direction  4 , thereby either retaining the release member  188  in an axially movable free state, or pushed distally toward the distal chamber wall  160 , during actuation of the actuation assembly  40 , enabling bi-directional free axial movement of the inner member  168  through the primary aperture  178 , without interfering with such relative movement by the release member  188 . 
       FIG.  16 B  shows the inner member  168  positioned at a more proximal position relative to its position within the outer member  142   d  shown in  FIG.  16 A . In the illustrated state, pulling force in the proximal direction is no longer applied to the inner member ( 168 ). When an external force (e.g., applied by the surrounding anatomy) strives to re-compress the valve  100 , thereby distancing the proximal and distal junctions away from each other, the plate  176   d  assumes an angled locking orientation which serves to lock the expansion and locking assembly  140   d  and retain the valve ( 100 ) in the expanded configuration, for example by being pushed against the distal chamber wall  160   d . 
       FIG.  17 A  shows an enlarged partial view of the expansion and locking assembly  140   d  around the chamber  152   d , which may correspond to the state shown in  FIG.  16 B . According to some embodiments, the plate  176   d  comprises a release aperture  179 , disposed within the first zone  154 , through which the release member  188   a , and more particularly, its distal end portion  192   a , extends. The release member distal end  193   a  may be attached to a retention feature  194 , extending radially outward from the release member distal end  193   a . In the exemplary embodiment illustrated in  FIGS.  16 A- 17 A , the retention feature  194   a  is in the form of a disc or plate, attached to the release member distal end  193   a . In alternative implementations, the retention feature  194  may be an attachable or integral flange extending radially outward from the release member distal end  193 . 
     The diameter of the release member distal end portion  192   a  is smaller than the diameter of the release aperture  179 , allowing it to extend therethrough, while the diameter of the retention feature  194   a , positioned distal to the release aperture  179 , is greater than the diameter of the release aperture  179 . 
     As shown in  FIGS.  16 B and  17 A , when the plate  176   d  is in the angled locking orientation, the release member  188  is free to be moved axially in any direction, enabling the plate first side  180   d  to push the retention feature  194   a , and the release member  188   a  therewith, in the distal direction  4 , if the plate  176   d  is pushed, for example, toward the distal chamber wall  160   d . In this manner, the release member  188   a  does not interfere with the transition of the plate  176   d  from the non-locking orientation to the angled locking orientation, and the optional translation of the plate  176   d  toward the distal chamber wall  160   d . 
     While  FIG.  16 B  illustrates the expansion and locking assembly  140   d  retained in a locked state, preventing re-compression of the prosthetic valve ( 100 ) by preventing advancement of the inner member  168  in the distal direction  4 , it may be desirable in some instances to allow valve re-expansion for the purpose of valve repositioning or re-crossing, for example. In such cases, the inner member  168  should be allowed to translate in the distal direction  4 , which is accomplished by actuation of a release assembly  50 .  FIG.  16 C  shows a state in which the release assembly  50  is actuated so as to allow valve re-compression. 
     The release support sleeve  56  surrounds the release arm  52  and may be connected to the handle  30 . The release support sleeve  56  and the outer member  142   d  are sized such that the distal lip of the release support sleeve  56  can abut or engage the outer member proximal end  146   d , such that the outer member  142   d  is prevented from moving proximally beyond the release support sleeve  56 . 
     In order to re-compress the frame  106 , and therefore the valve  100 , the release support sleeve  56  can be held firmly against the outer member  142   d , while the release arm  52  is pulled in a proximally oriented direction  2 . Since the release support sleeve  56  is being held against the outer member  142   d , which is connected to an outflow apex ( 132 ), the outflow end ( 103 ) of the frame ( 106 ) is prevented from moving relative to the release support sleeve  56 . As such, movement of the release arm  52  in a proximally oriented direction  2  can cause movement of the release member  188   a  in the same direction. 
     As Further shown in  FIG.  16 C , the retention feature  194   a , which is attached to the release member distal end  193   a , positioned distal to the plate  176   d , is consequently pulled in a proximal direction  2  as well, pressing the proximal surface of the retention feature  194   a  against the distal surface of the plate  176   d  around the release aperture  179 , thereby pulling the plate first side  180   d  in the same proximal direction, resulting in transitioning of the plate  176   d  from an angled locking orientation to a non-locking orientation, optionally pressing the  176   d  against the proximal chamber wall  160   d  to assume a substantially orthogonal orientation relative to the longitudinal axis of the inner member  168 . 
     Once the plate  176   d  assumes the non-locking orientation, the inner member  168  is free to axially move through the primary aperture  178   d  in any direction. In some embodiments, to facilitate valve re-compression in the state shown in  FIG.  16 C , the actuation member  42  may be pushed in a distally oriented direction  4 , pushing the inner member  168  therewith, thereby causing radial re-compression of the frame ( 106 ).  FIG.  16 C  shows the inner member proximal end portion  170  positioned distal to its position in  FIG.  16 B , as a result of simultaneously pushing of the actuation member  42  in a distal direction  4 , while pulling the release arm  52  in the proximal direction  2 . 
     In alternative embodiments, valve re-compression is not facilitated by directly applying a pushing force to the actuation members  42 , but rather by utilization of a re-compression mechanism of the type disclosed, for example, in International Application Publication No. WO 2020/081893, and U.S. application No. 62/928,320, which basically includes a flexible loop circumscribing the valve  100 , wherein loop contraction, for example operable tensioning the loop via handle  30 , facilitates valve compression therewith, during which the inner member  168  may passively advance in the distal direction  4  as shown in  FIG.  16 C . 
     Once the valve  100  is re-compressed, the release assembly  50  can be either released by not applying any pulling forces thereto, or alternatively by pushing it in a distal direction  4 , for example toward and/or into the niche  163  dimensioned to accommodate the retention feature  194   a , allowing the plate  176   d  to re-assume the angled locking orientation as shown in  FIG.  16 B . The valve  100  can be repositioned and re-expanded in the new position, by pulling the actuation member  42  in the proximal direction  2  as described in relation to  FIG.  16 A  above. Thus, numerous cycles of valve expansion and compression can be executed by transitioning between the states shown in  FIGS.  16 A,  16 B and/or  16 C  described above. 
     As shown in  FIG.  16 D , once the valve  100  assumes a final desired expansion diameter at the desired position within the site of implantation, the actuation member  42  and the release arm  52  may be rotated about their respective axes to unscrew them from the inner member  168  and the release member  188   a , respectively, enabling the actuation assemblies  40  and the release assemblies  50  to be pulled away and retracted, together with the delivery apparatus  12   b , from the patient&#39;s body, leaving the prosthetic valve ( 100 ) implanted in the patient. In some embodiments, the actuation member  42  and the release arm  52  may be rotated simultaneously, while in other embodiments, one may be rotated and release first, followed by rotation and releasing of the other. 
       FIG.  16 A- 17 A  illustrate a specific arrangement of a release member  188  coupled to a plate first side  180 , configured to transition the plate  176  to the non-locking orientation by pulling the plate first side  180  in the proximal direction.  FIG.  17 B  shows another embodiment of a release member  188  coupled to a plate second side  182 , instead of to the plate first side  180 . The outer member  142   f  shown in  FIG.  17 B  can be similar to the outer member  142   d  (shown, for example, in  FIG.  17 A ), wherein the difference lies in the position of the release channel  145   f  with respect to the primary channel  144   f , configured to enable the release member  188   c , to extend into the second zone  156  of the chamber  152   f . The plate  176   f  shown in  FIG.  17 B  can be similar to the plate  176   d  (shown, for example, in  FIG.  17 A ), except that while the release aperture  179   d  is disposed within the plate first side  180   d , the release aperture  179   f  is disposed within the plate second side  182   f . 
     The release member  188   c  can be identical to the release member  188   a , comprising a release member proximal end portion ( 190   c ) and a release member distal end portion  192   c , terminating at a release member distal end  193   c  which is attached to a retention feature  194   c . The retention feature  194   c , which may be identical to retention feature  194   a , is shown in  FIG.  17 B  to be positioned distal to the release aperture  179   f , and the release member  188   c  can be releasably attached to a release assembly  50 , and operable to pull the re-orient the plate  176   f  to the non-locking orientation, in the same manner described for release member  188   a  and plate  176   d  herein above and throughout  FIG.  16 A- 17 A , mutatis mutandis. 
     According to some embodiments, the handle  30   b  can comprise control mechanisms which may include steerable or rotatable knobs  32   b , levers, buttons and such, which in some implementation may be manually controllable by an operator to produce axial and/or rotatable movement of different components of the delivery apparatus  12   b . For example, the embodiment of handle  30   b  illustrated in  FIG.  13    comprises first, second, third and fourth knobs  32   b   a ,  32   b   b ,  32   b   c  and  32   b   d , respectively. 
     Knob  32   b   a , shown in  FIG.  13   , can be a rotatable knob configured to produce bi-directional axial translation of the outer shaft  20  relative to the prosthetic valve  100  in the distal and/or proximal directions, for example to retract the outer shaft  20  and expose the prosthetic valve  100  once it is positioned at or adjacent the desired site of implantation within the patient&#39;s body. For example, rotation of the knob  32   b   a  in a first direction (e.g., clockwise) can retract the outer shaft  20  proximally relative to the prosthetic valve  100 , and rotation of the knob  32   b   a  in a second direction (e.g., counterclockwise) can advance the outer shaft  20  distally. 
     Knob  32   b   b , shown in  FIG.  13   , can be a rotatable knob configured to steer the outer shaft  20  as it advances through the curvatures of the patient&#39;s vasculature. Particularly, the handle  30   b  may comprise, in some embodiments, a steering mechanism, which may include at least one pull wire (not shown) attached at its distal end to the outer shaft  20  (or other shafts of the delivery apparatus  12   b ), such that rotation of the knob  32   b   b  may vary the tension of the pull wire, which is effective to vary the curvature of the outer shaft  20 . 
     Knob  32   b   d , shown in  FIG.  13   , can be a rotatable knob configured to produce radial expansion and/or contraction of the prosthetic valve  100 . For example, rotation of the knob  32   b   d  can move the actuation member  42  and the actuation support sleeve  46  axially relative to one another, and optionally also move the release arm  52  and the release support sleeve  56  axially relative to one another. Rotation of the knob  32   b   d  in a first direction (e.g., clockwise) can radially expand the prosthetic valve  100 , for example by pulling the actuation members  42  in the proximal direction  2 , and rotation of the knob  32   b   d  in a second direction (e.g., counterclockwise) can re-compress the prosthetic valve  100 , for example by pulling the release arms  52  to allow such re-compression. 
     In alternative embodiments, two or more separate knobs may be configured to facilitate expansion and compression of the valve  100 . For example, one knob may control the actuation assemblies  40 , while another knob may control actuation of the release assemblies  50  (embodiments not shown). 
     Knob  32   b   c , shown in  FIG.  13   , can be a rotatable knob configured to release the prosthetic valve  100  from the delivery apparatus  12   b . For example, rotation of the knob  32   b   c  in a first direction (e.g., clockwise) can disengage both the actuation assemblies  40  and the release assemblies  50  from the expansion and locking assemblies  140   d  of the prosthetic valve  100 . In alternative embodiments, two or more separate knobs may be configured to facilitate release the prosthetic valve  100  from the delivery apparatus  12   b . For example, one knob may disengage the actuation assemblies  40  from the expansion and locking assemblies  140   d , while another knob may disengage the release assemblies  50  from the expansion and locking assemblies  140   d  (embodiments not shown). 
     Any of the knobs  32   b   a ,  32   b   b ,  32   b   c  and  32   b   d  may be implemented, in alternative embodiments, as other types of buttons, levers, knobs and the like, such as push/pull knobs which may be actuated by sliding or moving the knobs axially. 
       FIGS.  18 A- 18 D  show cross-sectional views in various stages of actuating the expansion and locking assembly  140   e , which are similar to the views and stages illustrated and described in conjunction with  FIGS.  16 A- 16 D  above, except that the release member  188   b  is implemented in a different manner than that of release member  188   a , as will be elaborated in greater detail hereinbelow. 
       FIG.  18 A  shows an initial state in which the actuation member distal end portion  44  is threaded into a threaded bore of the inner member proximal end portion  170 , and the release arm distal end portion  54  is threaded into a threaded bore of the release member proximal end portion  190   b . The inner member  168  extends through the primary channel  144   e  and the chamber  152   e  of the outer member  142   e , such that the inner member fastener ( 174 ) is distanced from the outer member fastener ( 150   e ) at a distance that may be associated with a compressed, or a partially compressed, configuration of the valve ( 100 ). In this state, the inner member  168  may extend distally from the outer member  142   e  such that the inner member fastener  174  is distanced distally away from the outer member distal end  147   e . The release member  188   a  extends through the release channel  145   e , and may partially extend into the chamber  152   d , wherein the release member distal end portion  192   b  is coupled to the plate  176   e . 
     In the actuation state shown in  FIG.  18 A , the actuation member  42  may be pulled in a proximally oriented direction  2 , while the actuation support sleeve  46  is held firmly against the outer member  142   e  so as to prevent the outflow end  103  of the frame  106  from moving relative to the actuation support sleeve  46 . As such, movement of the actuation member  42  in a proximally oriented direction  2  causes movement of the inner member  168  in the same direction, thereby causing the frame  106  to foreshorten axially and expand radially. Pulling the inner member  168  in a proximally oriented direction  2  (as shown in  FIG.  18 A ) may pull the plate  176   e  there-along, optionally (but not necessarily) until the plate  176   e  is pressed against the proximal chamber wall  158   e . 
     In some embodiments, the release arm  52  may be pulled in the proximal direction  2 , simultaneously with the pulling of the actuation member  42 , thereby pulling the release member  188   b  therewith in the proximal direction  2 . Alternatively, the release arm  52  may remain free or even pushed in the distal direction  4 , thereby either retaining the release member  188   b  in an axially movable free state, or pushed distally toward the distal chamber wall  160   e , respectively, during actuation of the actuation assembly  40 , enabling free movement of the inner member  168  through the primary aperture  178   e , without hindering such relative movement by the release member  188   b . 
       FIG.  18 B  shows the inner member  168  positioned at a more proximal position relative to its position within the outer member  142   e  shown in  FIG.  18 A . In the illustrated state, pulling force in the proximal direction is no longer applied to the inner member ( 168 ). When an external force (e.g., applied by the surrounding anatomy) strives to re-compress the valve  100 , thereby distancing the proximal and distal junctions away from each other, the plate  176   e  assumes an angled locking orientation which serves to lock the expansion and locking assembly  140   e  and retain the valve ( 100 ) in the expanded configuration, for example by being pushed against the distal chamber wall  160   e . 
       FIG.  19 A  shows an enlarged partial view of the expansion and locking assembly  140   e  around the chamber  152   e , which may correspond to the state shown in  FIG.  18 B . Unlike the embodiments illustrated in  FIGS.  16 A- 17 A , the plate  176   e  shown in  FIGS.  18 A- 19 A  does not include release aperture ( 179 ). As shown, a retention feature  194   b  may be pivotably attached to the release member distal end  193   b  via release member distal hinge  196   b , allowing the retention feature  194   b  to pivot about the axis defined by the hinge  196   b  (an axis which may be orthogonal to the cross-sectional plane shown in  FIG.  16 A- 17 A ). The retention feature  194   b  may be rigidly attached to the plate  176   e . For example, the distal surface of the retention feature  194   b  may be affixed to the proximal surface of the plate first side  180   e . Since the retention feature  194   b  is not positioned distal to the plate  176   e , the distal chamber wall  160  may be provided without a niche ( 163 ). 
     In alternative embodiments, the release member distal end portion  192  is directly attached to the plate  176  in a pivotable manner, allowing the plate  176  to pivot about a release member distal hinge  196 , without the use of an intermediate retention feature ( 194 ). 
       FIG.  18 C  shows a state in which the release assembly  50  is actuated so as to allow valve re-expansion. The release support sleeve  56  surrounds the release arm  52  and may be connected to the handle  30 . The release support sleeve  56  and the outer member  142   d  are sized such that the distal lip of the release support sleeve  56  can abut or engage the outer member proximal end  146   e , such that the outer member  142   e  is prevented from moving proximally beyond the release support sleeve  56 . 
     In order to re-compress the frame  106 , and therefore the valve  100 , the release support sleeve  56  can be held firmly against the outer member  142   e , while the release arm  52  is pulled in a proximally oriented direction  2 . Since the release support sleeve  56  is being held against the outer member  142   e , which is connected to an outflow apex ( 132 ), the outflow end ( 103 ) of the frame ( 106 ) is prevented from moving relative to the release support sleeve  56 . As such, movement of the release arm  52  in a proximally oriented direction  2  can cause movement of the release member  188   b  in the same direction. 
     As Further shown in  FIG.  18 C , the retention feature  194   b , which is pivotably attached to the release member distal end  193   b  and rigidly attached to the plate  176   d , moves along with the release member  188   b  and pulls the plate first side  180   e  in the same proximal direction, resulting in transitioning of the plate  176   e  from an angled locked orientation to a non-locking orientation, potentially pressing the  176   e  against the proximal chamber wall  160   e  to assume a substantially orthogonal orientation relative to the longitudinal axis of the inner member  168 . 
     Once the plate  176   e  assumes the non-locking orientation, the inner member  168  is free to axially move through the primary aperture  178   e  in any direction. In some embodiments, to facilitate valve re-compression in the state shown in  FIG.  18 C , the actuation member  42  may be pushed in a distally oriented direction  4 , pushing the inner member  168  therewith, thereby causing radial re-compression of the frame  106 .  FIG.  18 C  shows the inner member proximal end portion  170  positioned distal to its position in  FIG.  18 B , as a result of simultaneous pushing of the actuation member  42  in a distal direction  4 , while pulling the release arm  52  in the proximal direction  2 . 
     In alternative embodiments, valve re-compression is not facilitated by directly applying a pushing force on the actuation members  42 , but rather by utilization of a re-compression mechanism of the type disclosed, for example, in International Application Publication No. WO 2020/081893, and U.S. application No. 62/928,320, which basically includes a loop circumscribing the valve ( 100 ), wherein loop tensioning or contraction, for example operable via handle ( 30 ), facilitates valve contraction there-along, during which the inner member  168  may passively translate in the distal direction  4  as shown in  FIG.  18 C . 
     Once the valve  100  is re-compressed, the release assembly  50  can be either released by not applying any pulling forces thereto, or alternatively by pushing it in a distal direction  4 , allowing the plate  176   e  to re-assume the angled locking orientation as shown in  FIG.  18 B . The valve ( 100 ) can be repositioned and re-expanded in the new position, by pulling the actuation member  42  in the proximal direction  2  as described in relation to  FIG.  18 A . Thus, numerous cycles of valve expansion and compression can be executed by transitioning between the states shown in  FIGS.  18 A,  18 B and/or  18 C  described above. 
     As shown in  FIG.  18 D , once the valve  100  assumes a final desired expansion diameter at the proper position within the site of implantation, the actuation member  42  and the release arm  52  may be rotated about their respective axes to unscrew them from the inner member  168  and the release member  188   b , respectively, enabling the actuation assemblies  40  and the release assemblies  50  to be pulled away and retracted, together with the delivery apparatus  12   b , from the patient&#39;s body, leaving the prosthetic valve  100  implanted in the patient. In some embodiments, the actuation member  42  and the release arm  52  may be rotated may be rotated simultaneously, while in other embodiments, one may be rotated and release first, followed by rotation and releasing of the other. 
       FIG.  18 A- 19 A  illustrate a specific arrangement of a release member  188  coupled to a plate first side  180 , configured to transition the plate  176  to the non-locking orientation by pulling the plate first side  180  in the proximal direction, in a similar manner to that shown in  FIGS.  16 A- 17 A .  FIG.  19 B  shows an embodiment of a release member  188  coupled to a plate second side  182 , instead of to the plate first side  180 , in a manner similar to that described herein above with respect to  FIG.  17 B . The outer member  142   g  shown in  FIG.  19 B  can be similar to the outer member  142   e  (shown, for example, in  FIG.  19 A ), wherein the difference lies in the position of the release channel  145   g  with respect to the primary channel  144   g , configured to enable the release member  188   d  to extend into the second zone  156  of the chamber  152   g . The plate  176   g  shown in  FIG.  19 B  can be similar to the plate  176   e  (shown, for example, in  FIG.  19 A ), except that while the release aperture  179   e  is disposed within the plate first side  180   e , the release aperture  179   g  is disposed within the plate second side  182   g . 
     The release member  188   d  can be identical to the release member  188   b , comprising a release member proximal end portion ( 190   d ) and a release member distal end portion  192   d , terminating at a release member distal end  193   d . The retention feature  194   d , which may be identical to retention feature  194   b , may be pivotably attached to the release member distal end  193   d  via release member distal hinge  196   d , allowing the retention feature  194   d  to pivot about the axis defined by the hinge  196   d  (an axis which may be orthogonal to the cross-sectional plane shown in  FIG.  18 A- 17   ). The retention feature  194   d  may be rigidly attached to the plate  176   g . For example, the distal surface of the retention feature  194   d  may be affixed to the proximal surface of the plate second side  180   g . 
     The release member  188   d  can be releasably attached to a release assembly  50 , and operable to pull the re-orient the plate  176   g  to the non-locking orientation, in the same manner described for release member  188   b  and plate  176   e  herein above and throughout  FIG.  18 A- 19 A , mutatis mutandis. 
     While a threaded engagement is described throughout the current disclosure, serving as an optional reversible-attachment mechanism between the actuation assemblies  40  and the inner members  168 , or between the release assemblies  50  and the release members  188 , it is to be understood that in alternative implementations, other reversible attachment mechanisms may be utilized, configured to enable the inner member  168  and/or the release members  188  (when present) to be pulled or pushed by the actuation assemblies  40  and/or the release assemblies  50 , respectively, while enabling disconnection there-between in any suitable manner, potentially controllable by the handle  30 , so as to allow retraction of the delivery apparatus  12  from the patient&#39;s body at the end of the implantation procedure. 
       FIGS.  20 A- 20 B  show another embodiment of an expansion and locking assembly ( 140 ), comprising release member  188   e  extending through a release channel  145   h  of an outer member  142   h , and a plate  176   h  coupled to the chamber  152   h  via two springs  186   h  disposed at opposite sides of the inner member  168 , and configured to bias each side of the plate  176   h  in an opposite direction, in their free states, so as to bias the plate  176   h  to the angled locking orientation in their free state. 
     The outer member  142   h  can be similar to any other type of outer member ( 142 ) that includes a release channel  145   h  for a release member  188   h , except that the distal chamber wall  158   h  does not need to have an inclined or angled portion. As shown in the illustrated embodiment, both the distal wall first side  162   h  and the distal wall second side  164   h  may be provided as flat walls, oriented substantially perpendicularly with respect to the longitudinal axis of the inner member  168 . 
     The plate  176   h  comprises a primary aperture  178   h  through which the inner member extends, and may further engage the release member  188   h  at one of its sides, such as the plate first side  180   h  in the illustrated example. As shown, the release member distal end portion  192   e  may be coupled to the plate  176   h  (e.g., to the plate first side  180   h ) via a release member distal hinge  196   e , enabling the plate  176   h  to pivot about the hinge  196   e  with respect to the release member  188   h . It is to be understood the other coupling means between the release member  188   h  and the plate  176   h  may be applicable, such as via retention features  194   a ,  194   b ,  194   c  or  194   d  as described hereinabove with respect to  FIGS.  16 A- 19 B , and that a direct connection between a release member end portion ( 192 ) and a plate ( 176 ) via a hinge, such as the release member distal hinge  196  illustrated in  FIG.  20 A- 20 B , may be used with other embodiments, such as those described hereinabove for release members  188   b  or  188   d  (i.e., without the utilization of an intermediary retention feature such as retention feature  194   b  or  194   d ). 
     The outer member  142   h  may comprise a first spring  186   h   a , configured to bias the plate first side  180   h  in a proximal direction  2 , toward the proximal chamber wall  158   h , and a second spring  186   h   b , configured to bias the plate second side  182   h  in a distal direction  4 , toward the distal chamber wall  160   h . The first spring  186   h   a  can be a compression spring, disposed within the first zone ( 154 ) between the plate first side  180   h  and the distal wall first side  162   h . One end of the first spring  186   h   a  can be attached to the plate first side  180   h , and the other to the distal wall first side  162   h . The second spring  186   h   b  can be an extension spring, disposed within the first zone ( 156 ) between the plate second side  182   h  and the distal wall second side  164   h . One end of the second spring  186   h   b  can be attached to the plate second side  182   h , and the other to the distal wall second side  164   h . 
     In some implementations, the first spring  186   h   a  is configured to exert a proximally oriented biasing force which is greater in magnitude than the distally oriented biasing force exerted by the second spring  186   h   b  on the plate  176   h . In some implementations, the spring constant of the first spring  186   h   a  is higher than the spring constant of the second spring  186   h   b.    
       FIG.  20 A  shows both the first spring  186   h   a  and the second spring  186   h   b  in a free state thereof, without any external force applied to either one of the springs. In this free state, the plate first side  180   h  is biased in a first direction (e.g., the proximal direction  2 ) by the first spring  186   h   a , while the plate second side  182   h  is biased in a second direction (e.g., in a distal direction  4 ) by the second spring  186   h   b , resulting in the plate  176   h  being biased to the angled locking orientation, so as to prevent unintentional axial movement of the inner member  168  in the second direction (e.g., the distal direction  4 ), thereby locking it in position and preventing spontaneous re-compression of the valve (!00). 
     It is to be understood that the force exerted by the first spring  186   h   a  and the second spring  186   h   b  on the plate  176   h  are configured to be high enough to bias the plate  176   h  to the angled locking orientation in a free state, yet allow the plate  176   h  to assume a non-locking orientation when the inner member  168  is pulled in the first direction (e.g., the proximal direction). For example, the spring constants and/or spring dimensions, for both first and second springs  186   h   a ,  186   h   b , can be chosen to enable the inner member  168  to be pulled in a proximal direction  2 , when expansion of the valve ( 100 ) is desired. 
       FIG.  20 B  shows a release member  188   e  actuated to release the plate  176   h  from the angled locking orientation, so as to allow movement of the inner member  168  in a distal direction  4  to re-compress the valve ( 100 ). The release member  188   e  may be releasably attached to a release assembly  50 , for example, in the same manner illustrated and described hereinabove in conjunction with  FIGS.  16 A- 18 D . In the state shown in  FIG.  20 B , the release member  188   e  is pushed in the second direction (e.g., the distal direction  4 ), for example—via the release arm  52  attached to its proximal end portion ( 190 ), thereby pushing the plate  176   h , and more specifically, the plate second side  182   h , therewith, against the first spring  186   h   a . This serves to compress the first spring  186   h   a , allowing the plate  176   h  to assume a non-locking orientation, which in turn allows axial translation of the inner member  168  in the second direction (e.g., the distal direction  4 ) relative to the outer member  142   h . 
     In some embodiments, to facilitate valve re-compression in the state shown in  FIG.  20 B , an actuation member ( 42 ) may be pushed in a distally oriented direction  4 , pushing the inner member  168  therewith, thereby causing radial re-compression of the frame  106 . In alternative embodiments, valve re-compression is not facilitated by directly applying a pushing force on the actuation members ( 42 ), but rather by utilization of a re-compression mechanism of the type disclosed, for example, in International Application Publication No. WO 2020/081893, and U.S. application No. 62/928,320, which basically includes a loop circumscribing the valve ( 100 ), wherein loop tensioning or contraction, for example operable via handle ( 30 ), facilitates valve contraction there-along, during which the inner member  168  may passively translate in the distal direction  4  as shown in  FIG.  20 B . 
     While  FIGS.  20 A- 20 B  show a release member  188   h  attached to the plate  176   h , for example via a hinged connection, in other implementation a release member  188  may not be attached to the plate  176 , but may be rather spaced away from the plate  176 , or may contact the plate  176  but without applying any force thereto, in a free state such as the state shown in  FIG.  20 A , and may be pushed distally against the plate  176 , such that its distal end ( 193 ) may press against the plate  176  and push it in the same manner shown in  FIG.  20 B . 
     While the first spring  186   h   a  is illustrated in  FIGS.  20 A- 20 B  as a compression spring, disposed between the plate  176   h  and the distal chamber wall  160   h , in alternative implementations, the first spring  186   a  may be implemented as an extension spring disposed between the plate  176   h  and the proximal chamber wall  158   h , configured to bias the plate first side  180   h  in the same proxi 
     mal direction  2  as shown in  FIG.  20 A . Similarly, while the second spring  186   h   b  is illustrated in  FIGS.  20 A- 20 B  as an extension spring, disposed between the plate  176   h  and the distal chamber wall  160   h , in alternative implementations, the second spring  186   b  may be implemented as a compression spring disposed between the plate  176   h  and the proximal chamber wall  158   h , configured to bias the plate second side  182   h  in the same distal direction  4  as shown in  FIG.  20 A . 
     Additional Examples of the Disclosed Technology 
     In view of the above described implementations of the disclosed subject matter, this application discloses the additional examples enumerated below. It should be noted that one feature of an example in isolation or more than one feature of the example taken in combination and, optionally, in combination with one or more features of one or more further examples are further examples also falling within the disclosure of this application. 
     Example 1. A prosthetic valve, comprising: 
     a frame movable between a radially compressed and a radially expanded configuration; 
     at least one expansion and locking mechanism, comprising:
         an outer member, coupled to the frame at a first location;   an inner member, coupled to the frame at a second location spaced apart from the first location, the inner member extending at least partially into the outer member; and   at least one plate comprising a primary aperture, disposed around the inner member, the at least one plate configured to transition between an angled locking orientation and a non-locking orientation;       

     wherein movement of the inner member in a first direction, relative to the outer member, causes the frame to foreshorten axially and expand radially in a non-locking orientation of the at least one plate; 
     wherein in the absence of a force applied to the plate in the first direction, movement of the inner member in a second direction, relative to the outer member, causes the at least one plate to assume the angled locking orientation; and 
     wherein the at least one plate is configured to inhibit advancement of the inner member in the second direction relative to the outer member, when oriented in the angled locking orientation. 
     Example 2. The prosthetic valve of any example herein, particularly example 1, wherein the outer member further comprises a chamber comprising a proximal chamber wall and a distal chamber wall, and wherein the at least one plate is disposed within the chamber. 
     Example 3. The prosthetic valve of any example herein, particularly example 2, wherein the outer member further comprises a lateral opening exposing at least a portion of the chamber. 
     Example 4. The prosthetic valve of any example herein, particularly any one of examples 1 to 3, wherein the at least one plate has a disc-like circular or elliptic shape. 
     Example 5. The prosthetic valve of any example herein, particularly any one of examples 1 to 3, wherein the at least one plate has a rectangular shape. 
     Example 6. The prosthetic valve of any example herein, particularly any one of examples 1 to 5, wherein the at least one plate comprises a rigid material. 
     Example 7. The prosthetic valve of any example herein, particularly any one of examples 1 to 6, wherein the at least one plate comprises a plurality of plates. 
     Example 8. The prosthetic valve of any example herein, particularly example 2, wherein the distal chamber wall comprises at least one angled portion. 
     Example 9. The prosthetic valve of any example herein, particularly example 8, wherein the angle formed between the angled portion and the inner member is more acute than the angle formed between the plate and the inner member in the angled locking orientation. 
     Example 10. The prosthetic valve of any example herein, particularly any one of examples 2 to 9, wherein the diameter of the primary aperture is closely matched with the outer diameter of the inner member extending therethrough, such that axial movement of the inner member frictionally engages with the primary aperture. 
     Example 11. The prosthetic valve of any example herein, particularly example 10, wherein the diameter of the primary aperture is no more than 5 percent larger than the diameter of the inner member at the portion extending therethrough. 
     Example 12. The prosthetic valve of any example herein, particularly example 2, wherein at least a portion of the proximal chamber wall is substantially orthogonal to a longitudinal axis of the inner member. 
     Example 13. The prosthetic valve of any example herein, particularly any one of examples 2 to 12, wherein the outer member comprises a primary channel, configured to accommodate at least a portion of the inner member therein. 
     Example 14. The prosthetic valve of any example herein, particularly example 2, wherein the outer member further comprises a spring disposed within the chamber, configured to urge the at least one plate in the second direction. 
     Example 15. The prosthetic valve of any example herein, particularly example 14, wherein the spring is a helical spring coiled around the inner member. 
     Example 16. The prosthetic valve of any example herein, particularly example 14, wherein the spring is a helical spring disposed adjacent the inner member. 
     Example 17. The prosthetic valve of any example herein, particularly example 14, wherein the spring is a leaf spring. 
     Example 18. The prosthetic valve of any example herein, particularly example 2, wherein the plate is coupled to the proximal chamber wall via a plate hinge, and wherein the plate is configured to pivot about the plate hinge between the angled locking orientation and the non-locking orientation. 
     Example 19. The prosthetic valve of any example herein, particularly example 2, wherein the distal chamber wall comprises a proximally oriented protrusion. 
     Example 20. The prosthetic valve of any example herein, particularly any one of examples 2 to 13, wherein the at least one expansion and locking mechanism further comprises a release member, extending at least partially into the outer member, the release member coupled to the at least one plate, and configured to transition the at least one plate to the non-locking orientation, and/or retain the at least one plate in the non-locking orientation, when the release member is pulled in the second direction relative to the outer member. 
     Example 21. The prosthetic valve of any example herein, particularly example 20, wherein the outer member further comprises a release channel, configured to accommodate the release member therein. 
     Example 22. The prosthetic valve of any example herein, particularly any one of examples 20 to 21, wherein the plate further comprises a release aperture, wherein a distal end portion of the release member extends through the release aperture, and wherein a distal end of the release member comprises a retention feature distal to the release aperture. 
     Example 23. The prosthetic valve of any example herein, particularly example 22, wherein the distal chamber wall comprises a niche dimensioned to accommodate the retention feature. 
     Example 24. The prosthetic valve of any example herein, particularly any one of examples 20 to 21, wherein a distal end of the release member is pivotably coupled to the at least one plate via a release member distal hinge. 
     Example 25. The prosthetic valve of any example herein, particularly any one of examples 19 to 20, wherein the outer member further comprises a first spring and a second spring, disposed within the chamber at opposite sides of the inner member, wherein the first spring is configured to bias one side of the at least one plate in a first direction, and the second spring is configured to bias an opposite second side of the at least one plate in a second direction, thereby biasing the plate to the angled locking orientation in a free state of the first and second springs. 
     Example 26. The prosthetic valve of any example herein, particularly example 25, wherein the first spring is a compression spring, disposed between the at least one plate and the distal chamber wall, and wherein the second spring is an extension spring disposed between the at least one plate and the distal chamber wall. 
     Example 27. The prosthetic valve of any example herein, particularly any one of examples 1 to 26, wherein the outer member further comprises an outer member fastener extending radially outward, and wherein the outer member is coupled to the frame at the first location via the outer member fastener. 
     Example 28. The prosthetic valve of any example herein, particularly any one of examples 1 to 27, wherein the inner member further comprises an inner member fastener extending radially outward, and wherein the inner member is coupled to the frame at the second location via the inner member fastener. 
     Example 29. The prosthetic valve of any example herein, particularly any one of examples 1 to 28, wherein the frame comprises intersecting struts. 
     Example 30. A prosthetic valve, comprising: 
     a frame movable between a radially compressed and a radially expanded configuration; 
     at least one expansion and locking mechanism, comprising:
         an outer member, coupled to the frame at a first location;   at least one expansion and locking mechanism, comprising:   an inner member, coupled to the frame at a second location spaced apart from the first location, the inner member extending at least partially into the outer member;   at least one plate comprising a primary aperture, disposed around the inner member, the at least one plate configured to transition between an angled locking orientation and a non-locking orientation; and   at least one spring disposed between the outer member and the at least one plate;       

     wherein movement of the inner member in a first direction, relative to the outer member, causes the frame to foreshorten axially and expand radially in a non-locking orientation of the at least one plate; 
     wherein in the absence of a force applied to the plate in the first direction, the at least one spring is configured to bias the at least one plate to the angled locking orientation; and 
     wherein the at least one plate is configured to inhibit advancement of the inner member in the second direction relative to the outer member, when oriented in the angled locking orientation. 
     Example 31. The prosthetic valve of any example herein, particularly example 30, wherein the at least one plate has a disc-like circular or elliptic shape. 
     Example 32. The prosthetic valve of any example herein, particularly any one of examples 30 to 31, wherein the at least one plate has a rectangular shape. 
     Example 33. The prosthetic valve of any example herein, particularly any one of examples 30 to 32, wherein the at least one plate comprises a rigid material. 
     Example 34. The prosthetic valve of any example herein, particularly any one of examples 30 to 33, wherein the at least one plate comprises a plurality of plates. 
     Example 35. The prosthetic valve of any example herein, particularly any one of examples 30 to 34, wherein the diameter of the primary aperture is no more than 5 percent larger than the diameter of the inner member at the portion extending therethrough. 
     Example 36. The prosthetic valve of any example herein, particularly any one of examples 30 to 35, wherein the outer member comprises a primary channel, configured to accommodate at least a portion of the inner member therein. 
     Example 37. The prosthetic valve of any example herein, particularly any one of examples 30 to 36, wherein the outer member further comprises a chamber comprising a proximal chamber wall and a distal chamber wall, and wherein the at least one plate and the at least one spring are disposed within the chamber. 
     Example 38. The prosthetic valve of any example herein, particularly example 37, wherein the distal chamber wall comprises a proximally oriented protrusion. 
     Example 39. The prosthetic valve of any example herein, particularly example 37, wherein the distal chamber wall comprises at least one angled portion. 
     Example 40. The prosthetic valve of any example herein, particularly example 39, wherein the angle formed between the angled portion and the inner member is more acute than the angle formed between the plate and the inner member in the angled locking orientation. 
     Example 41. The prosthetic valve of any example herein, particularly any one of examples 37 to 40, wherein at least a portion of the proximal chamber wall is substantially orthogonal to a longitudinal axis of the inner member. 
     Example 42. The prosthetic valve of any example herein, particularly any one of examples 37 to 40, wherein the at least one spring comprises a helical spring coiled around the inner member. 
     Example 43. The prosthetic valve of any example herein, particularly example 42, wherein the coiled spring is a compression spring disposed between the proximal chamber wall and the at least one plate. 
     Example 44. The prosthetic valve of any example herein, particularly any one of examples 37 to 41, wherein the at least one spring comprises at least one helical spring disposed adjacent the inner member. 
     Example 45. The prosthetic valve of any example herein, particularly example 44, wherein the at least one helical spring is a compression spring disposed between the proximal chamber wall and the at least one plate. 
     Example 46. The prosthetic valve of any example herein, particularly example 44, wherein the at least one helical spring is an extension spring disposed between the distal chamber wall and the at least one plate. 
     Example 47. The prosthetic valve of any example herein, particularly any one of examples 37 to 44, wherein the at least one spring is a leaf spring. 
     Example 48. The prosthetic valve of any example herein, particularly any one of examples 37 to 40, wherein the at least one expansion and locking mechanism further comprises a release member, extending at least partially into the outer member, the release member coupled to the at least one plate, and configured to transition the at least one plate to the non-locking orientation, and/or retain the at least one plate in the non-locking orientation, when the release member is pulled in the second direction relative to the outer member. 
     Example 49. The prosthetic valve of any example herein, particularly example 48, wherein the outer member further comprises a release channel, configured to accommodate the release member therein. 
     Example 50. The prosthetic valve of any example herein, particularly any one of examples 48 to 49, wherein the at least one plate further comprises a release aperture, wherein a distal end portion of the release member extends through the release aperture, and wherein a distal end of the release member comprises a retention feature distal to the release aperture. 
     Example 51. The prosthetic valve of any example herein, particularly example 50, wherein the distal chamber wall comprises a niche dimensioned to accommodate the retention feature. 
     Example 52. The prosthetic valve of any example herein, particularly any one of examples 48 to 49, wherein a distal end of the release member is pivotably coupled to the at least one plate via a release member distal hinge. 
     Example 53. The prosthetic valve of any example herein, particularly example 48, wherein the at least one spring comprises a first spring and a second spring, both of which are disposed within the chamber at opposite sides of the inner member, wherein the first spring is configured to bias one side of the at least one plate in a first direction, and the second spring is configured to bias an opposite second side of the at least one plate in a second direction, thereby biasing the plate to the angled locking orientation in a free state of the first and second springs. 
     Example 54. The prosthetic valve of any example herein, particularly example 53, wherein the first spring is a compression spring, disposed between the at least one plate and the distal chamber wall, and wherein the second spring is an extension spring disposed between the at least one plate and the distal chamber wall. 
     Example 55. A delivery assembly, comprising: 
     a prosthetic valve comprising:
         a frame movable between a radially compressed and a radially expanded configuration;   at least one expansion and locking mechanism comprising:   an outer member having an outer member first end and an outer member second end, wherein the outer member is coupled to the frame at a first location;   an inner member having an inner member first end and an inner member second end, wherein the inner member is coupled to the frame at a second location spaced apart from the first location, and wherein the inner member extends at least partially into the outer member; and   at least one plate comprising a primary aperture, disposed around the inner member, the at least one plate configured to transition between an angled locking orientation and a non-locking orientation;       

     a delivery apparatus comprising:
         a handle;   a delivery shaft extending distally from the handle; and   at least one actuation assembly extending from the handle through the delivery shaft, and detachably coupled to the at least one expansion and locking assembly;       

     wherein the frame is movable from the radially compressed configuration to the radially expanded configuration upon actuating the at least one expansion and locking assembly by the at least one actuation assembly; 
     wherein movement of the inner member in a first direction, relative to the outer member, causes the frame to foreshorten axially and expand radially in a non-locking orientation of the at least one plate; 
     wherein in the absence of a force applied to the plate in the first direction, movement of the inner member in a second direction, relative to the outer member, causes the at least one plate to assume the angled locking orientation; and 
     wherein the at least one plate is configured to inhibit advancement of the inner member in the second direction relative to the outer member, when oriented in the angled locking orientation. 
     Example 56. The delivery assembly of any example herein, particularly example 55, wherein the at least one actuation assembly comprises an actuation member and an actuation support sleeve disposed around the actuation member, and wherein the actuation member and the actuation support sleeve are movable longitudinally relative to each other in a telescoping manner. 
     Example 57. The delivery assembly of any example herein, particularly example 56, wherein the at least one actuation member is chosen from: a wire, a cable, a rod, or a tube. 
     Example 58. The delivery assembly of any example herein, particularly any one of examples 56 to 57, wherein the actuation support sleeve is a tube or a sheath having sufficient rigidity, such that the actuation support sleeve can apply an axial force against the outer member without bending or buckling. 
     Example 59. The delivery assembly of any example herein, particularly any one of examples 56 to 58, wherein the at least one actuation member is threadedly engaged with the corresponding inner member. 
     Example 60. The delivery assembly of any example herein, particularly any one of examples 56 to 59, wherein the handle comprises a plurality of knobs. 
     Example 61. The delivery assembly of any example herein, particularly example 60, wherein at least one of the plurality of knobs is configured to axially move each actuation member relative to the respective actuation support sleeve. 
     Example 62. The delivery assembly of any example herein, particularly example 60, wherein at least one of the plurality of knobs is configured to disengage each actuation assembly from the respective expansion and locking assembly. 
     Example 63. The delivery assembly of any example herein, particularly any one of examples 55 to 62, wherein the outer member further comprises a chamber comprising a proximal chamber wall and a distal chamber wall, and wherein the at least one plate is disposed within the chamber. 
     Example 64. The delivery assembly of any example herein, particularly any one of examples 55 to 63, wherein the at least one plate has a disc-like circular or elliptic shape. 
     Example 65. The delivery assembly of any example herein, particularly any one of examples 55 to 63, wherein the at least one plate has a rectangular shape. 
     Example 66. The delivery assembly of any example herein, particularly any one of examples 55 to 65, wherein the at least one plate comprises a rigid material. 
     Example 67. The delivery assembly of any example herein, particularly any one of examples 55 to 66, wherein the at least one plate comprises a plurality of plates. 
     Example 68. The delivery assembly of any example herein, particularly example 63, wherein the distal chamber wall comprises at least one angled portion. 
     Example 69. The delivery assembly of any example herein, particularly example 68, wherein the angle formed between the angled portion and the inner member is more acute than the angle formed between the plate and the inner member in the angled locking orientation. 
     Example 70. The delivery assembly of any example herein, particularly any one of examples 55 to 69, wherein the diameter of the primary aperture is closely matched with the outer diameter of the inner member extending therethrough, such that axial movement of the inner member frictionally engages with the primary aperture. 
     Example 71. The delivery assembly of any example herein, particularly example 70, wherein the diameter of the primary aperture is no more than 5 percent larger than the diameter of the inner member at the portion extending therethrough. 
     Example 72. The delivery assembly of any example herein, particularly example 63, wherein at least a portion of the proximal chamber wall is substantially orthogonal to a longitudinal axis of the inner member. 
     Example 73. The delivery assembly of any example herein, particularly any one of examples 56 to 62, wherein the outer member comprises a primary channel, configured to accommodate at least a portion of the inner member and at least a portion of the actuation member therein. 
     Example 74. The delivery assembly of any example herein, particularly example 63, wherein the outer member further comprises a spring disposed within the chamber, configured to urge the at least one plate in the second direction. 
     Example 75. The delivery assembly of any example herein, particularly example 74, wherein the spring is a helical spring coiled around the inner member. 
     Example 76. The delivery assembly of any example herein, particularly example 74, wherein the spring is a helical spring disposed adjacent the inner member. 
     Example 77. The delivery assembly of any example herein, particularly example 74, wherein the spring is a leaf spring. 
     Example 78. The delivery assembly of any example herein, particularly example 63, wherein the plate is coupled to the proximal chamber wall via a plate hinge, and wherein the plate is configured to pivot about the plate hinge between the angled locking orientation and the non-locking orientation. 
     Example 79. The delivery assembly of any example herein, particularly example 63, wherein the distal chamber wall comprises a proximally oriented protrusion. 
     Example 80. A delivery assembly, comprising: 
     a prosthetic valve comprising:
         a frame movable between a radially compressed and a radially expanded configuration;   at least one expansion and locking mechanism comprising:
           an outer member having an outer member first end and an outer member second end, wherein the outer member is coupled to the frame at a first location;   an inner member having an inner member first end and an inner member second end, wherein the inner member is coupled to the frame at a second location spaced apart from the first location, and wherein the inner member extends at least partially into the outer member;   at least one plate comprising a primary aperture, disposed around the inner member, the at least one plate configured to transition between an angled locking orientation and a non-locking orientation; and   a release member extending at least partially into the outer member, the release member coupled to the at least one plate;   
               

     a delivery apparatus comprising:
         a handle;   a delivery shaft extending distally from the handle;   at least one actuation assembly extending from the handle through the delivery shaft, and detachably coupled to the at least one expansion and locking assembly; and   at least one release assembly extending from the handle through the delivery shaft, and detachably coupled to the at least one release member;       

     wherein the frame is movable from the radially compressed configuration to the radially expanded configuration upon actuating the at least one expansion and locking assembly by the at least one actuation assembly; 
     wherein movement of the inner member in a first direction, relative to the outer member, causes the frame to foreshorten axially and expand radially in a non-locking orientation of the at least one plate; 
     wherein in the absence of a force applied to the plate in the first direction, movement of the inner member in a second direction, relative to the outer member, causes the at least one plate to assume an angled locking orientation; 
     wherein the at least one plate is configured to inhibit advancement of the inner member in the second direction relative to the outer member, when oriented in the angled locking orientation; and 
     wherein the release member is configured to transition the at least one plate to the non-locking orientation, and/or retain the at least one plate in the non-locking orientation, when the release member is pulled by the release assembly in the first direction relative to the outer member. 
     Example 81. The delivery assembly of any example herein, particularly example 80, wherein the at least one actuation assembly comprises an actuation member and an actuation support sleeve disposed around the actuation member, and wherein the actuation member and the support sleeve are movable longitudinally relative to each other in a telescoping manner. 
     Example 82. The delivery assembly of any example herein, particularly example 81, wherein the at least one actuation member is chosen from: a wire, a cable, a rod, or a tube. 
     Example 83. The delivery assembly of any example herein, particularly any one of examples 81 to 82, wherein the support sleeve is a tube or a sheath having sufficient rigidity, such that the support sleeve can apply an axial force against the frame without bending or buckling. 
     Example 84. The delivery assembly of any example herein, particularly any one of examples 81 to 83, wherein the at least one actuation member is threadedly engaged with the corresponding inner member. 
     Example 85. The delivery assembly of any example herein, particularly any one of examples 81 to 84, wherein the at least one release assembly comprises a release arm and a release support sleeve disposed around the release arm, and wherein the release arm and the release support sleeve are movable longitudinally relative to each other in a telescoping manner. 
     Example 86. The delivery assembly of any example herein, particularly example 85, wherein the at least one release arm is chosen from: a wire, a cable, a rod, or a tube. 
     Example 87. The delivery assembly of any example herein, particularly any one of examples 85 to 86, wherein the release support sleeve is a tube or a sheath having sufficient rigidity, such that the release support sleeve can apply an axial force against the outer member without bending or buckling. 
     Example 88. The delivery assembly of any example herein, particularly any one of examples 85 to 87, wherein the at least one release arm is threadedly engaged with the corresponding release member. 
     Example 89. The delivery assembly of any example herein, particularly any one of examples 81 to 88, wherein the handle comprises a plurality of knobs. 
     Example 90. The delivery assembly of any example herein, particularly example 89, wherein at least one of the plurality of knobs is configured to axially move each actuation member relative to the respective actuation support sleeve. 
     Example 91. The delivery assembly of any example herein, particularly example 89, wherein at least one of the plurality of knobs is configured to axially move each release arm relative to the respective release support sleeve. 
     Example 92. The delivery assembly of any example herein, particularly example 89, wherein at least one of the plurality of knobs is configured to disengage each actuation assembly from the respective expansion and locking assembly. 
     Example 93. The delivery assembly of any example herein, particularly example 89, wherein at least one of the plurality of knobs is configured to disengage each release assembly from the respective expansion and locking assembly. 
     Example 94. The delivery assembly of any example herein, particularly any one of examples 80 to 93, wherein the outer member further comprises a chamber comprising a proximal chamber wall and a distal chamber wall, and wherein the at least one plate is disposed within the chamber. 
     Example 95. The delivery assembly of any example herein, particularly any one of examples 80 to 94, wherein the at least one plate has a disc-like circular or elliptic shape. 
     Example 96. The delivery assembly of any example herein, particularly any one of examples 80 to 95, wherein the at least one plate has a rectangular shape. 
     Example 97. The delivery assembly of any example herein, particularly any one of examples 80 to 96, wherein the at least one plate comprises a rigid material. 
     Example 98. The delivery assembly of any example herein, particularly any one of examples 80 to 97, wherein the at least one plate comprises a plurality of plates. 
     Example 99. The delivery assembly of any example herein, particularly example 94, wherein the distal chamber wall comprises at least one angled portion. 
     Example 100. The delivery assembly of any example herein, particularly example 99, wherein the angle formed between the angled portion and the inner member is more acute than the angle formed between the plate and the inner member in the angled locking orientation. 
     Example 101. The delivery assembly of any example herein, particularly any one of examples 80 to 100, wherein the diameter of the primary aperture is closely matched with the outer diameter of the inner member extending therethrough, such that axial movement of the inner member frictionally engages with the primary aperture. 
     Example 102. The delivery assembly of any example herein, particularly example 101, wherein the diameter of the primary aperture is no more than 5 percent larger than the diameter of the inner member at the portion extending therethrough. 
     Example 103. The delivery assembly of any example herein, particularly example 94, wherein at least a portion of the proximal chamber wall is substantially orthogonal to a longitudinal axis of the inner member. 
     Example 104. The delivery assembly of any example herein, particularly any one of examples 81 to 84, wherein the outer member comprises a primary channel, configured to accommodate at least a portion of the inner member and at least a portion of the actuation member therein. 
     Example 105. The delivery assembly of any example herein, particularly any one of examples 85 to 88, wherein the outer member comprises a release channel, configured to accommodate at least a portion of the release member and at least a portion of the release arm therein. 
     Example 106. The delivery assembly of any example herein, particularly example 94, wherein the outer member further comprises a spring disposed within the chamber, configured to urge the at least one plate in the second direction. 
     Example 107. The delivery assembly of any example herein, particularly example 106, wherein the spring is a helical spring coiled around the inner member. 
     Example 108. The delivery assembly of any example herein, particularly example 106, wherein the spring is a helical spring disposed adjacent the inner member. 
     Example 109. The delivery assembly of any example herein, particularly example 106, wherein the spring is a leaf spring. 
     Example 110. The delivery assembly of any example herein, particularly example 94, wherein the plate is coupled to the proximal chamber wall via a plate hinge, and wherein the plate is configured to pivot about the plate hinge between the angled locking orientation and the non-locking orientation. 
     Example 111. The delivery assembly of any example herein, particularly example 94, wherein the distal chamber wall comprises a proximally oriented protrusion. 
     Example 112. The delivery assembly of any example herein, particularly any one of examples 80 to 111, wherein the at least one plate further comprises a release aperture, wherein a distal end portion of the release member extends through the release aperture, and wherein a distal end of the release member comprises a retention feature distal to the release aperture. 
     Example 113. The delivery assembly of any example herein, particularly example 94, wherein the at least one plate further comprises a release aperture, wherein a distal end portion of the release member extends through the release aperture, wherein a distal end of the release member comprises a retention feature distal to the release aperture, and wherein the distal chamber wall comprises a niche dimensioned to accommodate the retention feature. 
     Example 114. The delivery assembly of any example herein, particularly any one of examples 80 to 111, wherein a distal end of the release member is pivotably coupled to the at least one plate via a release member distal hinge. 
     Example 115. The delivery assembly of any example herein, particularly any one of examples 80 to 105, wherein the outer member further comprises a first spring and a second spring, disposed within the chamber at opposite sides of the inner member, wherein the first spring is configured to bias one side of the at least one plate in a first direction, and the second spring is configured to bias an opposite second side of the at least one plate in a second direction, thereby biasing the plate to the angled locking orientation in a free state of the first and second springs. 
     Example 116. The delivery assembly of any example herein, particularly example 94, wherein the outer member further comprises a first spring and a second spring, disposed within the chamber at opposite sides of the inner member, wherein the first spring is configured to bias one side of the at least one plate in a first direction, and the second spring is configured to bias an opposite second side of the at least one plate in a second direction, thereby biasing the plate to the angled locking orientation in a free state of the first and second springs, wherein the first spring is a compression spring, disposed between the at least one plate and the distal chamber wall, and wherein the second spring is an extension spring disposed between the at least one plate and the distal chamber wall. 
     Example 117. A method of implanting a prosthetic valve, the method comprising: 
     positioning a prosthetic valve at a target site in a patient&#39;s body using a delivery apparatus, wherein the prosthetic valve comprises at least one expansion and locking assembly, the expansion and locking assembly comprising an outer member, an inner member partially disposed within, and movable axially relative to, the outer member, and at least one plate dispose within the outer member and around the inner member, and wherein the delivery apparatus comprises at least one actuation assembly, detachably coupled to the at least one expansion and locking assembly; 
     radially expanding the prosthetic valve from a radially compressed configuration to a radially expanded configuration, by applying, via the at least one actuation assembly, a pull force on the inner member, configured to axially move the inner member in a first direction relative to the outer member; and 
     locking the expansion and locking assembly by releasing the pull force exerted on the inner member by the actuation assembly, thereby allowing the at least one plate to assume an angled locking orientation. 
     Example 118. The method of any example herein, particularly example 117, wherein the radially expanded configuration comprises partially expanded configurations and/or a fully expanded configuration, and wherein the step of radially expanding the prosthetic valve is executed again after the locking step, so as to reorient the at least one plate from the angled locking orientation to a non-locking orientation, allowing further expansion of the prosthetic valve from a partially expanded configuration to another partially expanded configuration or to a fully expanded configuration. 
     Example 119. The method of any example herein, particularly any one of examples 117 to 118, wherein the at least one actuation assembly comprises an actuation member detachably coupled to the inner member, and an actuation support sleeve disposed around the actuation member, and wherein the step of radially expanding the prosthetic valve comprises exerting a pull force to move the actuation member in a first direction relative to the actuation support sleeve, while keeping the actuation support sleeve stationary or moved in an opposite second direction, so as to apply a counter force against the outer member. 
     Example 120. The method of any example herein, particularly example 119, further comprising a step of detaching the at least one actuation member from the at least one inner member, and retrieving the delivery apparatus from the patient&#39;s body. 
     Example 121. The method of any example herein, particularly example 120, wherein the at least one actuation member is threadedly engaged with the at least one inner member, and wherein detaching the at least one actuation member comprises rotating the at least one actuation member around a longitudinal axis thereof. 
     Example 122. A method of implanting a prosthetic valve, the method comprising: 
     positioning a prosthetic valve at a target site in a patient&#39;s body using a delivery apparatus, wherein the prosthetic valve comprises at least one expansion and locking assembly, the expansion and locking assembly comprising an outer member, an inner member partially disposed within, and movable axially relative to, the outer member, at least one plate dispose within the outer member and around the inner member, and a release member disposed within the outer member and axially movable relative thereto, the release member coupled to the at least one plate, and wherein the expansion and locking assembly comprises at least one actuation assembly detachably coupled to the at least one expansion and locking assembly, and at least one release assembly detachably coupled to the release member; 
     radially expanding the prosthetic valve from a radially compressed configuration to a radially expanded configuration, by applying, via the at least one actuation assembly, a pull force on the inner member, configured to axially move the inner member in a first direction relative to the outer member; 
     locking the expansion and locking assembly by releasing the pull force exerted on the inner member by the actuation assembly, thereby allowing the at least one plate to assume an angled locking orientation; 
     unlocking the expansion and locking assembly by applying, via the at least one release assembly, a pull force on the release member, configured to transition the at least one plate from the angled locking orientation to a non-locking orientation; and 
     re-compressing the prosthetic valve such that the at least one inner member is moved in a second direction relative to the at least one outer member. 
     Example 123. The method of any example herein, particularly example 122, wherein any of the steps of radially expanding the prosthetic valve, locking, unlocking, and re-compressing the prosthetic valve, are repeated for any desired number of times and in any order, so as to reach a final desired expansion diameter of the prosthetic valve. 
     Example 124. The method of any example herein, particularly any one of examples 122 to 123, further comprising a step of re-positioning the prosthetic valve using the delivery apparatus, after the step of re-compressing the prosthetic valve. 
     Example 125. The method of any example herein, particularly any one of examples 122 to 124, wherein the at least one actuation assembly comprises an actuation member detachably coupled to the inner member, and an actuation support sleeve disposed around the actuation member, wherein the at least one release assembly comprises a release arm detachably coupled to the release member, and a release support sleeve disposed around the release arm, wherein the step of radially expanding the prosthetic valve comprises exerting a pull force to move the actuation member in a first direction relative to the actuation support sleeve, while keeping the actuation support sleeve stationary or moved in an opposite second direction, so as to apply a counter force against the outer member, and wherein the step of unlocking the prosthetic valve comprises exerting a pull force to move the release arm in a first direction relative to the release support sleeve, while keeping the release support sleeve stationary or moved in an opposite second direction, so as to apply a counter force against the outer member. 
     Example 126. The method of any example herein, particularly example 125, further comprising steps of detaching the at least one actuation member from the at least one inner member, detaching the at least one release arm from the release member, and retrieving the delivery apparatus from the patient&#39;s body. 
     Example 127. The method of any example herein, particularly example 126, wherein the at least one actuation member is threadedly engaged with the at least one inner member, wherein the at least one release arm is threadedly engaged with the at least one release member, wherein detaching the at least one actuation member comprises rotating the at least one actuation member around a longitudinal axis thereof, and wherein detaching the at least one release arm comprises rotating the at least one release arm around a longitudinal axis thereof. 
     Example 128. A method for assembling an expansion and locking mechanism, comprising the steps of: 
     providing an outer member comprising a chamber and a lateral opening exposing at least a portion of the chamber; 
     inserting at least one plate, comprising a primary aperture, into the chamber through the lateral opening; 
     orienting the at least one plate in a substantially orthogonal orientation, relative to a longitudinal axis of the outer member; and 
     inserting the inner member into the outer member, through the primary aperture of the at least one plate. 
     It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination or as suitable in any other described embodiment of the invention. No feature described in the context of an embodiment is to be considered an essential feature of that embodiment, unless explicitly specified as such. 
     In view of the many possible embodiments to which the principles of the disclosure may be applied, it should be recognized that the illustrated embodiments are only preferred examples and should not be taken as limiting the scope. Rather, the scope is defined by the following claims. We therefore claim all that comes within the scope and spirit of these claims.