Patent Description:
The present disclosure relates to prosthetic heart valves, and to methods and assemblies for forming and installing leaflet assemblies to frames of such prosthetic heart valves.

The human heart can suffer from various valvular diseases. These valvular diseases can result in significant malfunctioning of the heart and ultimately require repair of the native valve or replacement of the native valve with an artificial valve. There are a number of known repair devices (e.g., stents) and artificial valves, as well as a number of known methods of implanting these devices and valves in humans. Percutaneous and minimally-invasive surgical approaches are used in various procedures to deliver prosthetic medical devices to locations inside the body that are not readily accessible by surgery or where access without surgery is desirable. In one specific example, a prosthetic heart valve can be mounted in a crimped state on the distal end of a delivery device and advanced through the patient's vasculature (e.g., through a femoral artery and the aorta) until the prosthetic valve reaches the implantation site in the heart. The prosthetic valve is then expanded to its functional size, for example, by inflating a balloon on which the prosthetic valve is mounted, actuating a mechanical actuator that applies an expansion force to the prosthetic valve, or by deploying the prosthetic valve from a sheath of the delivery device so that the prosthetic valve can self-expand to its functional size. Prosthetic valves that rely on a mechanical actuator for expansion can be referred to as "mechanically expandable" prosthetic heart valves. The actuator typically takes the form of pull cables, sutures, wires and/or shafts that are configured to transmit expansion forces from a handle of the delivery apparatus to the prosthetic valve.

Expandable, transcatheter heart valves can comprise an annular metal frame or stent and prosthetic leaflets mounted inside the frame. The leaflets can be attached to a portion of the frame via commissure tab assemblies, for example, by passing through and/or wrapping around a commissure window. Each commissure tab assembly can be preassembled by connecting tabs of adjacent leaflets to each other and then attached by suture to commissure window. However, such commissure tab assemblies may be relatively complex and time-consuming to assemble. Moreover, certain configurations of the commissure window may suffer from reliability issues (e.g., due to undesirable changes in shape during expansion of the prosthetic heart valve) and/or commissure mounting problems.

Accordingly, a need exists for improved prosthetic heart valves and methods for securing leaflet assemblies to a frame of the prosthetic heart valve.

<CIT> describes a prosthetic heart valve that includes a valve frame having a wireform portion and a stent portion. The wireform and stent portions can be undetachably coupled together via a plurality of upright struts so as to form a one-piece prosthetic heart valve frame. Alternatively, a self-expanding wireform portion and a balloon-expandable stent portion can be coupled together via one or more leaflets and a subassembly having a flexible leaflet support stent and a sealing ring. The wireform portion can include cusps and commissures configured to support a plurality of leaflets. The prosthetic valve can be radially collapsible for minimally invasive and/or transcatheter delivery techniques. Disclosed embodiments can also provide flexion of the wireform portion (e.g., of the commissures) in response to physiologic pulsatile loading when the valve is implanted in a patient's native valve annulus. Methods of making and using prosthetic heart valves are also disclosed.

<CIT> relates to an assembly for implanting a prosthetic heart valve in a patient's body, the assembly comprising: a delivery apparatus comprising an elongated shaft; a radially expandable and collapsible prosthetic heart valve mounted on the shaft in a radially collapsed configuration for delivery into the body, the prosthetic heart valve comprising an annular frame and a leaflet structure within the frame; wherein the frame comprises a plurality of angularly spaced commissure windows each comprising an enclosed opening between first and second axially oriented side struts, and the leaflet structure comprises a plurality of commissure portions that extend outwardly through respective commissure windows; and wherein the commissure windows are depressed radially inwardly relative to portions of the frame between adjacent commissure windows when the valve is radially collapsed on the shaft.

The embodiments of a prosthetic heart valve and a method for assembling a prosthetic heart valve are defined by independent claims <NUM> and <NUM>.

In particular, a prosthetic heart valve comprises a valvular structure, formed by a plurality of leaflets, and is supported by an expandable annular frame of the prosthetic heart valve. Each leaflet has a pair of tabs. Each tab has upper and lower portions. Commissures formed by paired tabs of adjacent leaflets are coupled to corresponding commissure windows to support the valvular structure within the frame. Each commissure window has upper and lower openings or channels separated from each other by a crossbar. For example, each commissure window can be substantially H-shaped in respective side view, with the crossbar connecting between a pair of struts extending along an axial direction of the valve. A thickness of each axially-extending strut of the H-shaped commissure window and a location of the crossbar along the axial direction can be selected such that the H-shape does not deform, or experiences minimal deformation, as the frame transitions between fully-expanded and crimped states.

The upper and lower tab portions extend through the upper and lower openings, respectively, of the corresponding commissure window. One or more wedge members can be coupled to the tab portions. The wedge member(s) can prevent the leaflet tab from passing back through the commissure window, thereby retaining the valvular structure to the annular frame. Embodiments of the disclosed subject matter may thus offer simple and cost-effective methods for reliably mounting the valvular structure to the frame of the prosthetic valve while avoiding stitching sutures (or at least reducing the impact thereof) through dynamic portions of the leaflets, thereby reducing the risk of leaflet tearing.

Further, the assembly method for a prosthetic heart valve comprises, inter alia, providing first and second leaflets for a valvular structure of the prosthetic heart valve. Each leaflet has a pair of tabs, and one of the tabs is on an opposite side from the other of the tabs with respect to a centerline of the leaflet. Each tab has an upper tab portion and a lower tab portion separated from the upper tab portion along a direction parallel to the centerline by a gap. The method further comprises disposing the upper and lower tab portions of a second tab of the pair of tabs of the second leaflet adjacent to the upper and lower tab portions of a first tab of the pair of tabs of the first leaflet, respectively. The method can also comprise stitching together the upper tab portions of the first and second leaflet tabs, and stitching together the lower tab portions of the first and second leaflet tabs. The method can further comprise folding the upper and lower tab portions of the first leaflet tab. The method comprises conveying the first and second leaflet tabs through a commissure window of an expandable annular frame of the prosthetic heart valve. The commissure window has upper and lower openings separated from each other along an axial direction of the annular frame by a crossbar. The conveying is along a radial direction of the annular frame from a radially inner-side of the commissure window to a radially-outer side of the commissure window. The conveying is such that the upper tab portions are inserted through the upper opening and the lower tab portions are inserted through the lower opening. The method can further comprise inserting one or more wedge members between facing surfaces of the folded upper tab portion of the first leaflet tab and between facing surfaces of the folded lower tab portion of the first leaflet tab. The method can also comprise folding the upper tab portion of the second leaflet tab around the folded upper tab portion of the first leaflet tab, and folding the lower tab portion of the second leaflet tab around the folded lower tab portion of the first leaflet tab. The method can further comprise stitching together the one or more wedge members and the upper tab portions of the first and second leaflet tabs, and stitching together the one or more wedge members and the lower tab portions of the first and second leaflet tabs.

The assembly method can further comprise disposing the upper tab portion of a first tab of the pair of tabs of the first leaflet to surround at least a portion of a circumference of a first wedge member, and disposing the lower tab portion of the first leaflet tab to surround at least a portion of a circumference of a second wedge member. The method can also comprise stitching together the first wedge member and at least the upper tab portion of the first leaflet tab, and stitching together the second wedge member and at least the lower tab portion of the first leaflet tab. The method can further comprise conveying the first wedge member, the second wedge member, and the first leaflet tab through a commissure window of an expandable annular frame of the prosthetic heart valve. The commissure window has upper and lower openings separated from each other along an axial direction of the annular frame by a crossbar. The conveying is along a radial direction of the annular frame from a radially inner-side of the commissure window to a radially-outer side of the commissure window. The conveying can be such that the upper tab portion of the first leaflet tab and the first wedge member are inserted through the upper opening and the lower tab portion of the first leaflet tab and the second wedge member are inserted through the lower opening. The method can also comprise conveying a second tab of the pair of tabs of the second leaflet through the commissure window. The conveying is along the radial direction from the radially inner-side of the commissure window to the radially-outer side of the commissure window and such that the upper tab portion of the second leaflet tab is inserted through the upper opening and the lower tab portion of the second leaflet tab is inserted through the lower opening. The method can further comprise folding the upper tab portion of the second leaflet tab around the upper tab portion of the first leaflet tab, and folding the lower tab portion of the second leaflet tab around the lower tab portion of the first leaflet tab. The method can also comprise stitching together the first wedge member, and the upper tab portions of the first and second leaflet tabs, and stitching together the second wedge member and the lower tab portions of the first and second leaflet tabs.

The assembly method can also comprise disposing the upper and lower tab portions of the first leaflet tab to surround at least a portion of a circumference of one or more wedge members. The method can further comprise folding the upper tab portion of the second leaflet tab around the upper tab portion of the first leaflet tab, and folding the lower tab portion of the second leaflet tab around the lower tab portion of the first leaflet tab. The method can also comprise stitching together the one or more wedge members and the upper tab portions of the first and second leaflet tabs, and stitching together the one or more wedge members and the lower tab portions of the first and second leaflet tabs.

The annular frame can be expandable between a crimped state having a first diameter and an expanded state having a second diameter greater than the first diameter.

The various innovations of this disclosure are used in combination or separately.

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. 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.

As used herein with reference to the prosthetic heart valve assembly and implantation and structures of the prosthetic heart valve, "proximal" refers to a position, direction, or portion of a component that is closer to the user and a handle of the delivery system that is outside the patient, while "distal" refers to a position, direction, or portion of a component that is further away from the user and the handle and closer to the implantation site. The terms "longitudinal" and "axial" refer to an axis extending in the proximal and distal directions, unless otherwise expressly defined.

The terms "axial direction," "radial direction," and "circumferential direction" have been used herein to describe the arrangement of components and assembly of commissures to respective windows, relative to the geometry of the frame of the prosthetic heart valve. Such terms have been used for convenient description, but the disclosed embodiments are not strictly limited to the description. In particular, where a component or action is described relative to a particular direction, directions parallel to the specified direction as well as minor deviations therefrom. Thus, a description of a component extending along an axial direction of the frame does not require the component to be aligned with a center of the frame; rather, the component can extend substantially along a direction parallel to a central axis of the frame.

As used herein, the terms "integrally formed" and "unitary construction" refer to a construction that does not include any welds, fasteners, or other means for securing separately formed pieces of material to each other.

As used herein, operations that occur "simultaneously" or "concurrently" occur generally at the same time as one another, although delays in the occurrence of operation relative to the other due to, for example, spacing between components, are expressly within the scope of the above terms, absent specific contrary language.

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. " Further, the terms "coupled" and "connected" generally mean electrically, electromagnetically, and/or physically (e.g., mechanically or chemically) coupled or linked and does not exclude the presence of intermediate elements between the coupled or associated items absent specific contrary language. 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.

Described herein are examples of prosthetic heart valves, annular frames with commissure windows and leaflets for prosthetic heart valves, and methods for assembling leaflets to commissure windows of annular frames to form prosthetic heart valves. A valvular structure, which is formed by multiple leaflets, is supported by an expandable annular frame of the prosthetic heart valve. Each tab of the leaflet has upper and lower portions separated from each other by a gap. Commissures formed by paired tabs of adjacent leaflets are coupled to corresponding commissure windows to support the valvular structure within the frame. Each commissure window has upper and lower openings separated from each other by a crossbar. The upper and lower tab portions extend through the upper and lower openings, respectively, of the corresponding commissure window. One or more wedge members coupled to the tab portions can prevent the leaflet tab from passing back through the commissure window, thereby retaining the valvular structure to the annular frame. As a result, a position of the leaflet assembly for a prosthetic heart valve may be effectively locked in place during assembly and use of the prosthetic heart valve, and a time and effort for securing the leaflet assembly to the frame of the prosthetic heart valve may be reduced.

In some embodiments, each commissure window can be substantially H-shaped in respective side view, with the crossbar connecting between a pair of struts extending along an axial direction of the valve. A thickness of each axially-extending strut of the H-shaped commissure window and a location of the crossbar along the axial direction can be selected such that the H-shape does not deform, or experiences minimal deformation, as the frame transitions between fully-expanded and crimped states, thereby reducing the risk of damage to the leaflets and/or detachment of the leaflets from the frame.

<FIG> illustrate various features of an exemplary prosthetic heart valve <NUM>, according to one or more embodiments of the disclosed subject matter. The prosthetic heart valve <NUM> can be radially compressible and expandable between a radially compressed configuration for delivery (e.g., a crimped state) into a patient, for example, as illustrated in <FIG>, and a radially expanded configuration (e.g., a deployed state), for example, as illustrated in <FIG> and <FIG>. In particular embodiments, the prosthetic heart valve <NUM> can be implanted within the native aortic annulus, although it also can be implanted at other locations in the heart, including within the native mitral valve, the native pulmonary valve, or the native tricuspid valve.

The prosthetic heart valve <NUM> includes an annular stent or frame <NUM>. The frame <NUM> can have a first axial end <NUM> and a second axial end <NUM>. In the depicted embodiment, the first axial end <NUM> can be an outflow end, and the second axial end <NUM> can be an inflow end. The outflow end <NUM> can be coupled to a delivery apparatus for delivering and implanting the prosthetic heart valve <NUM> within the native aortic valve using a transfemoral, retrograde delivery approach. Thus, in the delivery configuration of the prosthetic heart valve, the outflow end <NUM> can be considered the proximal-most end of the prosthetic valve. In other embodiments, the inflow end <NUM> can instead be coupled to the delivery apparatus, depending on the particular native valve being replaced and the delivery technique that is used (e.g., trans-septal, transapical, etc.). For example, the inflow end <NUM> can be coupled to the delivery apparatus (and therefore would be the proximal-most end of the prosthetic heart valve in the delivery configuration) when delivering the prosthetic heart valve to the native mitral valve via a trans-septal delivery approach.

In some embodiments, the frame <NUM>, or components thereof (e.g., struts and/or fasteners), can be made of any of various suitable plastically-expandable materials (e.g., stainless steel, etc.) or self-expanding materials (e.g., nickel titanium alloy (NiTi), such as nitinol), as known in the art. Suitable plastically-expandable materials that can be used to form the frame <NUM> include, without limitation, stainless steel, biocompatible high-strength alloys (e.g., a cobalt-chromium or a nickel-cobalt-chromium alloys), polymers, or combinations thereof. In particular embodiments, frame <NUM> is made of a nickel-cobalt-chromium-molybdenum alloy, such as MP35N® alloy (SPS Technologies, Jenkintown, Pennsylvania), which is equivalent to UNS R30035 alloy (covered by ASTM F562-<NUM>). MP35N® alloy/UNS R30035 alloy comprises <NUM>% nickel, <NUM>% cobalt, <NUM>% chromium, and <NUM>% molybdenum, by weight.

When constructed of a plastically-expandable material, the frame <NUM> (and thus the prosthetic valve <NUM>) can be crimped to a radially collapsed configuration on a delivery catheter and then expanded inside a patient by an inflatable balloon or equivalent expansion mechanism. For example, <FIG> illustrates expansion of the frame <NUM> from a crimped state (e.g., <FIG>) to a deployed state (e.g., <FIG>) using inflatable balloon <NUM>. When constructed of a self-expandable material, the frame <NUM> (and thus the prosthetic valve <NUM>) can be crimped to a radially collapsed configuration and restrained in the collapsed configuration by insertion into a sheath or equivalent mechanism of a delivery catheter. Once inside the body, the prosthetic valve can be advanced from the delivery sheath, which allows the prosthetic valve to expand to its functional size.

For example, referring to <FIG>, a delivery apparatus <NUM> including a handle <NUM> can be used to deliver and implant the prosthetic valve <NUM> in the following exemplary manner. The prosthetic valve <NUM> can be disposed on a distal end portion <NUM> of the delivery apparatus <NUM> in a radially compressed state. The prosthetic valve <NUM> can be crimped on an inflatable balloon <NUM> (e.g., balloon <NUM>) or another type of expansion member that can be used to radially expand the prosthetic valve <NUM>. The distal end portion <NUM> of the delivery apparatus <NUM>, including prosthetic valve <NUM>, can be advanced through the vasculature to a selected implantation site (e.g., within a previously implanted host valve and/or within a native valve). In the illustrated embodiment, the distal end portion of the delivery apparatus <NUM> and the prosthetic valve <NUM> are inserted into a femoral artery and advanced through the femoral artery and the aorta and positioned within the native aortic valve <NUM> or a host valve previously implanted within the native aortic valve <NUM>. The prosthetic valve <NUM> can then be deployed at the implantation site, such as by inflating the balloon <NUM>. Further details of delivery apparatuses that can be used to deliver and implant plastically expandable prosthetic valves, such as the prosthetic valve <NUM> (or any other prosthetic valves disclosed herein), are disclosed in <CIT><CIT>and <CIT>.

If the prosthetic valve <NUM> being implanted is a self-expandable prosthetic valve, the prosthetic valve can be retained in a radially compressed state within a delivery capsule or sheath of the delivery apparatus when inserted into and advanced through the patient's vasculature to the desired implantation site. Once positioned at the desired implantation site, the prosthetic valve can be deployed from the delivery capsule, which allows the prosthetic valve to self-expand to its radially-expanded, functional size within the native valve or a previously implanted host valve. Further details of delivery apparatuses that can be used to deliver and implant self-expandable prosthetic valves (including any of the prosthetic valves disclosed herein when the frames are constructed of a self-expandable material such as Nitinol) are disclosed in <CIT> and <CIT>.

In some embodiments, struts of the frame <NUM> are pivotable or bendable relative to each other to permit radial expansion and contraction of the frame <NUM>. For example, the frame <NUM> can be formed (e.g., via laser cutting, electroforming or physical vapor deposition) from a single piece of material (e.g., a metal tube). In other embodiments, the frame <NUM> can be constructed by forming individual components (e.g., the struts and fasteners of the frame) and then mechanically assembling and connecting the individual components together. For example, instead of the strut structure illustrated in <FIG>, the frame can have individual diagonally-extending struts pivotably coupled to one another at one or more pivot joints along the length of each strut, as described in <CIT>, <CIT>, and <CIT>. Further details regarding exemplary constructions of frame <NUM> and/or prosthetic heart valve <NUM> are described in <CIT> and <CIT>, <CIT>, International Publication No. <CIT>, and International Application No. <CIT>.

As illustrated in <FIG>, frame <NUM> can include a plurality of struts that are angled with respect to an axial direction (A) of the frame <NUM> so as to extend along a circumferential direction (C) of the frame <NUM>. The struts can be organized into circumferentially-extending rows, for example, a first row <NUM> of angled struts <NUM> and angled struts <NUM> arranged end-to-end and extending circumferentially at the outflow end <NUM> of the frame <NUM>; a second row <NUM> of angled struts <NUM> and <NUM> arranged end-to-end and extending circumferentially; a third row <NUM> of angled struts <NUM> arranged end-to-end and extending circumferentially; and a fourth row <NUM> of angled struts <NUM> arranged end-to-end and extending circumferentially at the inflow end <NUM> of the frame <NUM>. In some embodiments, a magnitude of the angle with respect to the axial direction for the struts <NUM>, <NUM> in the first row <NUM> can be the same as, or substantially similar to (e.g., within <NUM>%), that for the struts <NUM> in the fourth row <NUM>. In some embodiments, a magnitude of the angle with respect to the axial direction for the struts <NUM>, <NUM> in the second row <NUM> and/or the struts <NUM> in the third row <NUM> can be different than that for the struts <NUM>, <NUM> in the first row <NUM> and/or the struts <NUM> in the fourth row <NUM>.

Within first row <NUM>, angled struts <NUM>, <NUM> can connect to (e.g., by joining or integrally formed with) adjacent angled struts <NUM>, <NUM> via joint or union <NUM>. Similarly, within fourth row <NUM>, angled struts <NUM> can connect to (e.g., by joining or integrally formed with) adjacent angled struts <NUM> via joint or union <NUM>. Angled struts <NUM>, <NUM> of the second row <NUM> and angled struts <NUM> of the third row <NUM> can connect to (e.g., by joining or integrally formed with) each other via joint or union <NUM>. Angled struts <NUM> of the third row <NUM> and angled struts <NUM> of the fourth row <NUM> can connect to (e.g., by joining or integrally formed with) each other via joint or union <NUM>.

Between the first row <NUM> and the second row <NUM>, the frame <NUM> can further include a plurality of support struts <NUM> and a plurality of commissure windows <NUM>. Each support strut <NUM> can extend substantially parallel to the axial direction (A) of the frame <NUM>. Each support strut <NUM> can connect to (e.g., by joining or integrally formed with) an adjacent pair of the angled struts <NUM> of the first row <NUM> at its first end (e.g., closest to outflow end <NUM> of the frame <NUM>) and can connect to (e.g., by joining or integrally formed with) an adjacent pair of the angled struts <NUM> of the second row <NUM> at its opposite second end (e.g., closest to inflow end <NUM> of the frame <NUM>). Similarly, each commissure window <NUM> can connect to (e.g., by joining or integrally formed with) an adjacent pair of angled struts <NUM> of the first row <NUM> at its first end (e.g., closest to outflow end <NUM> of the frame <NUM>) and can connect to (e.g., by joining or integrally formed with) an adjacent pair of angled struts <NUM> of the second row <NUM> at its opposite second end (e.g., closest to inflow end <NUM> of the frame <NUM>).

The angled struts, support struts, commissure windows, and other frame portions collectively define an open-cell lattice structure, with each of the cells <NUM>-<NUM> being open along a radial direction (R) of the annular frame. At the outflow end <NUM> of the valve <NUM>, each cell <NUM> can be defined, at least in part, by a pair of angled struts <NUM> of the first row <NUM>, a pair of support struts <NUM>, and a pair of angled struts <NUM> of the second row <NUM>. Also at the outflow end <NUM> of the valve <NUM>, each cell <NUM> can be defined, at least in part, by angled strut <NUM> and angled strut <NUM> of the first row <NUM>, a support strut <NUM>, a commissure window <NUM>, and angled strut <NUM> and angled strut <NUM> of the second row <NUM>. At the inflow end <NUM> of the valve, each cell <NUM> can be defined, at least in part, by a pair of angled struts <NUM> of the third row <NUM> and a pair of angled struts <NUM> of the fourth row <NUM>. In between cells <NUM> at the outflow end and cells <NUM> at the inflow end along the axial direction, each cell <NUM> can be defined, at least in part, by a pair of angled struts <NUM> of the second row <NUM> and a pair of angled struts <NUM> of the third row <NUM>. In between cells <NUM> at the outflow end and cells <NUM> at the inflow end along the axial direction, each cell <NUM> can be defined, at least in part, by a pair of angled struts <NUM> of the second row <NUM> and a pair of angled struts <NUM> of the third row <NUM>.

In the illustrated embodiment, each cell <NUM>, <NUM> at the outflow end <NUM> has a respective open area that is greater than that of the cells <NUM> at the inflow end <NUM>. Each of the cells <NUM>, <NUM> can have a respective open area that is between that of the outflow end cells <NUM>, <NUM> and the inflow end cells <NUM>. The relatively-larger openings of cells <NUM>, <NUM> at the outflow end <NUM> can allow portions of the leaflets of the valvular structure to protrude or bulge into and/or through the openings of the cells when the frame <NUM> is crimped, for example, to minimize crimping profile of the valve <NUM>. In other embodiments, cells <NUM>-<NUM> can have substantially the same open areas, the cells <NUM> at the inflow end <NUM> can have the largest open area instead of cells <NUM>, <NUM>, or the intermediate cells <NUM>, <NUM> can have the largest open area instead of cells <NUM>, <NUM>.

The frame <NUM> can be formed with a plurality of circumferentially-spaced commissure windows <NUM> that are adapted to couple the valvular structure <NUM> to the frame <NUM>. In particular, each commissure <NUM> of the valvular structure <NUM> is mounted to a respective one of the commissure windows <NUM>. The support struts <NUM> and the commissure windows <NUM> can be disposed at equal intervals along the circumferential direction of the frame <NUM>. In the illustrated embodiment, the valvular structure <NUM> comprises three leaflets <NUM> (e.g., a tricuspid configuration), and the commissure windows <NUM> are equally spaced at <NUM>° intervals (i.e., <NUM>°, <NUM>°, and <NUM>°) along the circumference of the frame <NUM>. A pair of support struts <NUM> are disposed along the circumference of the frame between each sequential pair of the commissure windows <NUM> and equally spaced from each other. Thus, either a support strut <NUM> or a commissure window <NUM> can be disposed at regular intervals around the circumference of the frame <NUM>, for example, at each <NUM>° interval.

Other spacings and numbers of supports struts <NUM> and commissure windows <NUM> are also possible according to one or more contemplated embodiments. For example, a single support strut <NUM> can be disposed between each sequential pair of commissure windows <NUM>. In such an example, either a support strut <NUM> or a commissure window <NUM> can be disposed at <NUM>° intervals around the circumference of the frame <NUM>. In another example, the valvular structure <NUM> comprises two leaflets <NUM> (e.g., a bicuspid configuration), and the commissure windows <NUM> are disposed on opposite sides of the frame (e.g., aligned on a same diameter of the frame). Multiple support struts <NUM> can be disposed along the circumference of the frame between the pair of commissure windows <NUM>, and each support strut <NUM> may be disposed on an opposite side of the frame from another support strut <NUM> (e.g., both aligned on a same diameter of the frame).

As shown in FIGS. 2A-<FIG>, each commissure window <NUM> can be formed by a pair of window struts <NUM>, <NUM> and a crossbar <NUM>. Window struts <NUM>, <NUM> can extend substantially parallel to the axial direction of the frame <NUM>. Each window strut <NUM>, <NUM> can connect to (e.g., by joining or integrally formed with) an adjacent angled strut <NUM> at its first end (e.g., closest to the outflow end <NUM> of the frame <NUM>) and connect to (e.g., by joining or integrally formed with) an adjacent angled strut <NUM> at its second end (e.g., closets to the inflow end <NUM> of the frame <NUM>). The crossbar <NUM> can extend between the window struts <NUM>, <NUM> along the circumferential direction and connect with the window struts <NUM>, <NUM>, thereby dividing a spacing between the window struts <NUM>, <NUM> into an upper window or opening <NUM> and a lower window or opening <NUM>. For example, each commissure window <NUM> is constructed to have a substantially H-shape in respective side view.

The upper opening <NUM>, which is defined by facing surfaces of portions of the window struts <NUM>, <NUM> at the first end and an upper surface of the crossbar <NUM>, can be open to the outflow end <NUM> along the axial direction of the valve <NUM>. The lower opening <NUM>, which is defined by facing surfaces of portions of the window struts <NUM>, <NUM> at the second end and a lower surface of the crossbar <NUM>, can be open to an adjacent cell <NUM> along the axial direction of the valve <NUM>. Lower opening <NUM> of the window <NUM> is closed to the inflow end <NUM> of the valve <NUM> by virtue of union <NUM>, which closes cell <NUM> to the inflow end <NUM> of the valve <NUM>. However, in other embodiments, union <NUM> of cell <NUM> can be omitted, thereby allowing lower opening <NUM> of commissure window <NUM> to be open to the inflow end <NUM> while upper opening <NUM> of commissure window <NUM> is open to the outflow end <NUM>. In still other embodiments, lower opening <NUM> of commissure window <NUM> can be open to the inflow end <NUM> (e.g., via removal of union <NUM> of cell <NUM>) while upper opening <NUM> of commissure window <NUM> can be closed to the outflow end <NUM> (e.g., by providing another crossbar or union between angled struts <NUM> at an end of the upper opening <NUM>).

The window struts <NUM>, <NUM> can be spaced from each other along the circumferential direction by a gap width, W<NUM>. The size of the upper and lower openings <NUM>, <NUM> is thus defined by the spacing between struts <NUM>, <NUM> and the position of the crossbar <NUM>. Alternatively, the upper opening <NUM> can have a different gap width than that of the lower opening <NUM>. In some embodiments, the gap width W<NUM> can be defined based on the size of leaflet tabs that are inserted into the openings <NUM>, <NUM> of the commissure window <NUM>. For example, the gap width W<NUM> can be greater than twice a thickness of a leaflet tab, and/or less than four times the thickness of the leaflet tab. A commissure <NUM> formed by a pair of leaflet tabs can thus be inserted through the gap width W<NUM> of each opening <NUM>, <NUM>, but is prevented from passing back through the opening upon folding of the leaflet tab in combination with one or more wedge members, as described in further detail below.

The commissure window <NUM> can have a length, L, along the axial direction of the frame <NUM> between first ends of the window struts <NUM>, <NUM> (e.g., ends closest to the outflow end <NUM>) and second ends of the window struts <NUM>, <NUM> (e.g., ends closest to the inflow end <NUM>). In some embodiments, the crossbar <NUM> can be offset from a midpoint of the window struts <NUM>, <NUM> (e.g., L/<NUM>) along the axial direction of the frame <NUM>, for example, between the outflow end <NUM> and the window strut midpoints. For example, a length, L<NUM>, of the upper opening <NUM>, as measured from the first ends of the window struts <NUM> to a middle of the crossbar <NUM>, is less than a length, L<NUM>, measured from the second ends of the window struts <NUM>, <NUM> to the middle of the crossbar <NUM>, such that the upper opening <NUM> is smaller (e.g., in terms of dimension along the axial direction or open area) than the lower opening <NUM>. For example, a ratio of L<NUM> to L<NUM> (e.g., L<NUM>/L<NUM>) can be in a range of <NUM> to <NUM>, inclusive.

In some embodiments, each window strut <NUM>, <NUM> can have a width, W<NUM>, along the circumferential direction of the frame <NUM> that is relatively larger than that of the surrounding angled struts <NUM>, <NUM>. For example, each angled strut <NUM>, <NUM> can have a width, W<NUM>, measured in a direction perpendicular to its direction of extension, and W<NUM> may be greater than W<NUM>. In some embodiments, the other angled struts <NUM>, <NUM>, <NUM>, and <NUM> can each have a width that is the same as or substantially similar (e.g., within <NUM>%) to the width W<NUM> of angled struts <NUM>, <NUM>. Thus, each window strut <NUM>, <NUM> can be wider than the angled struts of the frame <NUM>.

In some embodiments, the sizing and/or location of components of the commissure window <NUM> can be tailored to avoid formation of convex or concave contours along the struts <NUM>, <NUM> during transition between crimped (<FIG>) and fully expanded (<FIG>) configurations of the valve <NUM>. For example, by increasing widths W<NUM> of the window struts <NUM>, <NUM>, the stiffness of the window struts can be increased such that the struts maintain a substantially linear contour during the transition. Alternatively or additionally, the sizing and/or location of components of the commissure window <NUM> can be tailored such that the gap widths W<NUM> of the upper opening <NUM> and/or the lower opening <NUM> remain substantially constant (e.g., variations of <NUM>% or less) as the valve <NUM> transitions between crimped (<FIG>) and fully expanded (<FIG>) configurations. For example, by positioning the crossbar <NUM> at a particular location along the axial direction, circumferentially-directed forces acting on the first ends of the struts <NUM>, <NUM> can be balanced with circumferentially-directed forces acting on the second ends of the struts <NUM>, <NUM>. In combination with the increased widths of the window struts <NUM>, <NUM>, the balancing can allow the widths W<NUM> of the upper and lower openings to remain substantially constant during the transition.

For example, both the location of the crossbar <NUM> along the axial direction of the frame <NUM> and the widths W<NUM> of the window struts <NUM>, <NUM> can be selected such that the shape of the commissure window <NUM> does not deform, or experiences only minimal deformation (e.g., no more than <NUM>% variation), as the frame <NUM> transitions between fully expanded and crimped states, in order to reduce the risk of damage to and/or detachment of the leaflets. In some embodiments, finite element analysis (FEA) can be used to determine optimal values for the widths for the struts <NUM>, <NUM> and axial location of crossbar <NUM>, which values may depend on the particular construction of the valve frame <NUM> (e.g., material composition, number and geometry of open cells, sizes and angles of adjacent struts <NUM>, <NUM>, etc.).

Alternatively, or additionally, the axial location for the crossbar <NUM> can be based on relative positions along the axial direction of the angled struts <NUM>, <NUM>. <FIG> shows a section view for a commissure window <NUM> and surrounding angled struts <NUM>, <NUM>, when the valve <NUM> is at a configuration midway between the fully-expanded and crimped states. In <FIG>, h<NUM> represents a relative length along the axial direction for angled strut <NUM> as measured from one end of strut <NUM> (adjacent to the first end of window strut <NUM>) to an opposite end of strut <NUM> (at union <NUM>), and h<NUM> represents a relative length along the axial direction for angled strut <NUM> as measured from one end of strut <NUM> (adjacent to the second end of the window strut <NUM>) to an opposite end of strut <NUM> (at union <NUM>). The angled strut <NUM> is associated with a relative distance y<NUM>, measured along the axial direction from a middle of crossbar <NUM> to the end of strut <NUM> at union <NUM>. The angled strut <NUM> is also associated with a relative distance y<NUM>, measured along the axial direction from the middle of crossbar <NUM> to the end of strut <NUM> at union <NUM>. To avoid (or at least reduce) deformation of the commissure window <NUM>, the location of the crossbar <NUM> can be selected such that the (h<NUM>×y<NUM>)/(h<NUM>×y<NUM>) is within a range of <NUM>-<NUM>, inclusive, preferably <NUM>-<NUM>, inclusive. For example, the location of the crossbar <NUM> can be selected such that (h<NUM>×y<NUM>)/(h<NUM>×y<NUM>) ≈ <NUM>. Note that the values recited above are for hi, h<NUM>, y<NUM>, and y<NUM> measured when the frame <NUM> is midway (e.g., at a mean diameter, D<NUM> = (D<NUM>-D<NUM>)/<NUM>) between the fully-expanded (D<NUM>) and crimped (D<NUM>) states.

Using the crossbar location, the width W<NUM> of the window strut <NUM> can be derived based on forces applied by angled struts <NUM>, <NUM>, for example, such that the maximum force applied along the circumferential direction to the angled strut <NUM> (e.g., F<NUM>) during transition between crimped and expanded states results in minimal deflection of the first end of the window strut <NUM> and such that the maximum force applied along the circumferential direction to the angle strut <NUM> (e.g., F<NUM>) during the transition between states results in minimal deflection of the second end of the window strut <NUM>. In some embodiments, the other window strut <NUM> of the commissure window <NUM> can have dimensions (e.g., width W<NUM> and length along the axial direction) identical to that of window strut <NUM> for symmetrical application of forces.

In some embodiments, each support strut <NUM> can also have a width along the circumferential direction of the frame <NUM> that is relatively larger than the of the surrounding angled struts <NUM>, <NUM>. For example, the angled struts <NUM>, <NUM> can also have a width, W<NUM>, measured in a direction perpendicular to its direction of extension, and a minimum width of the support strut <NUM> can be greater than W<NUM>. In the illustrated embodiment, each support strut <NUM> can have a width (as measured along the circumferential direction) that varies along the axial direction of the frame <NUM>. For example, opposite ends of the support strut <NUM> can have a relatively larger width while a mid-portion between the opposite ends can have a relatively smaller width. Thus, each support strut <NUM> can have a dog-bone shape in respective side view, with a recess <NUM> being formed between the larger-width ends of the strut <NUM>. When the frame <NUM> is in the crimped configuration (e.g., as shown in <FIG>), the dog-bone shape of the support strut <NUM> can complement a shape of a facing strut <NUM>, <NUM> of the adjacent commissure window <NUM>, with a portion of the facing strut <NUM>, <NUM> fitting into recess <NUM>. The dog-bone shape of the support strut <NUM> can thus allow the frame <NUM> to achieve a minimum crimping profile despite the presence of the commissure windows <NUM>. In some embodiments, some of the support struts <NUM> may have a width that is substantially constant along the axial direction while other of the support struts <NUM> that are immediately adjacent to one of the commissure windows may have the dog-bone shape.

The prosthetic valve <NUM> also includes a valvular structure <NUM> configured for allowing blood flow through the frame <NUM> in one direction, for example, to regulate the flow of blood through the prosthetic heart valve <NUM> from the inflow end <NUM> to the outflow end <NUM>. The valvular structure <NUM> can include, for example, a leaflet assembly formed by one or more leaflets <NUM> (three leaflets illustrated in <FIG>) made of a flexible material. Tabs of adjacent leaflets <NUM> can be arranged together to form commissures <NUM> that are coupled (directly or indirectly) to respective commissure windows <NUM> of the frame <NUM>, thereby securing at least a portion of the valvular structure <NUM> to the frame <NUM>.

As shown in <FIG>, each leaflet <NUM> can comprise a main, cusp edge portion <NUM>, two leaflet tabs (also referred to herein as commissure tabs) <NUM> at opposing ends of the leaflet <NUM>, and an upper edge portion <NUM>. The cusp edge portion <NUM>, leaflet tabs <NUM>, and upper edge portion <NUM> may be arranged around an outer perimeter of the leaflet <NUM>. The upper edge portion <NUM> can extend between the two leaflet tabs <NUM> at an upper edge of the leaflet <NUM>, and the cusp edge portion <NUM> can extend between the two leaflet tabs <NUM> at a lower edge of the leaflet <NUM>. As used here, "upper" and "lower" may be relative to a central longitudinal axis of the prosthetic heart valve <NUM> when the valvular structure is installed and coupled to frame <NUM>, with upper being closer to the outflow end of the valve <NUM> and lower being closer to the inflow end of the valve <NUM>. The upper edge of the leaflet <NUM> can be referred to as the "free edge" or the "coaptation edge" of the leaflet.

In some embodiments, the cusp edge portion <NUM> has a curved, scalloped shape (as shown in <FIG>). Thus, the cusp edge portion <NUM> may curve between the two leaflet tabs <NUM>. <FIG> further illustrates a centerline <NUM> for each of the individual leaflets <NUM>, which may also be a centerline of the leaflet assembly. For example, when assembled, the centerlines <NUM> for each of the leaflets <NUM> may overlap. Further, as shown in <FIG>, the leaflet tabs <NUM> may be arranged at opposing ends of the leaflet <NUM>, across the centerline <NUM> from one another. In some embodiments, the leaflets and/or components of the leaflet assembly may have symmetry with respect to the centerline <NUM>.

The leaflets <NUM> of the valvular structure <NUM> can be made from in whole or part, biological materials, bio-compatible synthetic materials, or other such materials. Suitable biological materials can include, for example, bovine pericardium (or pericardium from other sources). Further details regarding transcatheter prosthetic heart valves, including the manner in which the valvular structure can be coupled to the frame <NUM> of the prosthetic heart valve <NUM>, can be found, for example, in <CIT>, <CIT><CIT><CIT><CIT>, and <CIT>, and <CIT>.

The tabs <NUM> of adjacent leaflets <NUM> are arranged together to form commissures <NUM> that are coupled to respective commissure windows <NUM>, thereby securing at least a portion of the valvular structure <NUM> to the frame <NUM>. Each tab <NUM> of the leaflet <NUM> has an upper tab portion <NUM> and a lower tab portion <NUM>. A gap <NUM> along a direction parallel to centerline <NUM> can separate the upper tab portion <NUM> from the lower tab portion <NUM>. Thus, the upper tab portion <NUM> extends from an end surface <NUM> of gap <NUM> outward (e.g., in a direction away from centerline <NUM>) and terminates at free end <NUM>. Similarly, the lower tab portion <NUM> extends from end surface <NUM> of gap <NUM> outward and terminates at free end <NUM>. In some embodiments, the upper and lower tab portions extend substantially parallel to each other, thereby forming a sideways U-shape or C-shape in side view. A length of the upper tab portion <NUM> along a direction perpendicular to centerline <NUM> can be substantially the same as that of the lower tab portion <NUM>. However, the height of the upper tab portion <NUM> along a direction parallel to centerline <NUM> may be different than that of the lower tab portion <NUM>. For example, upper tab portion <NUM> can have a height that corresponds to a size of upper opening <NUM> (e.g., length L<NUM> minus part of the thickness of crossbar <NUM> in <FIG>) of commissure window <NUM>, while lower tab portion <NUM> can have a height that corresponds to a size of the lower opening <NUM> (e.g., length L<NUM> minus part of the thickness of crossbar <NUM> in <FIG>) of commissure window <NUM>.

<FIG> shows an exemplary arrangement of leaflets 110a, 110b assembled to an H-shaped commissure window <NUM>, according to one or more embodiments of the disclosed subject matter. Tabs <NUM> of adjacent leaflets 110a, 110b are paired together and inserted into commissure window <NUM> (e.g., by conveying from a radially-inner side to a radially-outer side of the window <NUM>), with upper tab portions 164a, 164b of each leaflet 110a, 110b extending through the upper opening <NUM> and lower tab portions 166a, 166b of each leaflet extending through the lower opening <NUM>. The gaps separating the upper and lower tabs portions (of which, only gap 168b is visible in <FIG>) can correspond to a location of the crossbar <NUM> of the window <NUM>, and the end surface <NUM> of each gap <NUM> can be arranged to abut, or at least approach, a radially-inner surface of the crossbar <NUM> once the commissure is fully installed to the window <NUM>.

The upper tab portions 164a, 164b and the lower tab portions 166a, 166b can be wrapped around a wedge member <NUM> (or multiple wedge members) and coupled thereto. For example, the leaflet tabs and the wedge member <NUM> can be coupled to each other using one or more sutures, adhesive, welding, and/or any other means for attaching leaflets to wedge members. In some embodiments, a thickness of the combination of the wrapped tab portions and the wedge member <NUM> is greater than width W<NUM> of the openings <NUM>, <NUM> of commissure window <NUM>, thereby preventing the combination from sliding radially inward and back through commissure window <NUM>. Alternatively, or additionally, the wedge member <NUM> can be a single continuous member that extends along the axial direction between the upper tab portions <NUM> and the lower tab portions <NUM>. In such configurations, the wedge member <NUM> may interact with the radially-outer side of the crossbar <NUM> to prevent the combination from sliding radially inward and back through commissure window <NUM>.

The one or more wedge members <NUM> can be formed from a relatively thick, multifilament or monofilament suture, yarn or cable (e.g., a braided, polyester suture, such as an Ethibond suture), a piece of cloth or fabric folded one or more times to increase its thickness, or any other structure. For example, the disclosed wedge members, or sutures coupled thereto, can be formed of a material that does not encourage tissue ingrowth, such as ultrahigh molecular weight polyethylene (UHMPE), polyethylene terephthalate (PET), polyurethane (PU), or polytetrafluoroethylene (PTFE). Alternatively, or additionally, any other material that is minimally porous, configured to prevent or minimize neo-vascularization, or does not allow tissue anchoring can be used for the disclosed wedge members. Alternatively, or additionally, the disclosed wedge members can be a coated or laminated polymeric material. In some embodiments, the material for the disclosed wedge members can be a polymer material that is processed in a manner, or otherwise configured, to reduce the likelihood for tissue ingrowth. For example, if exposure of the material to certain levels of heat may induce thrombogenicity, the materials for the disclosed wedge members may be processed in a manner that avoids or reduces such heating steps.

In the illustrated embodiment, commissure windows <NUM> are formed as part of the lattice structure of the frame <NUM>. In other embodiments, commissure windows <NUM> may instead be formed in another structure of the frame <NUM> or as a separate structure attached to the frame <NUM>. For example, in some embodiments, the prosthetic valve includes one or more actuators coupled to the frame to cause transition of the valve between crimped and expanded configurations, and/or one or more locking mechanisms that maintains a shape of the frame after expansion or contraction. In addition to or in place of commissure windows provided in the lattice structure of the frame, at least one of the actuators or locking mechanisms can include an H-shaped commissure window formed therein and can be used to mount a commissure of the valvular assembly thereto. Further details of the actuators, locking mechanisms and delivery apparatuses for actuating the actuators can be found in <CIT>, <CIT>, and <CIT>. Any of the actuators and locking mechanisms disclosed in the previously filed applications can be incorporated in any of the prosthetic valves disclosed herein. Further, any of the delivery apparatuses disclosed in the previously filed applications can be used to deliver and implant any of the prosthetic valves discloses herein.

Alternatively, or additionally, the prosthetic valve can include one or more support members that form a part of or are coupled to the annular frame and that include an H-shaped commissure window. For example, the support member can be an axially extending member that is attached to a radially-inner surface of the frame, and the H-shaped commissure window can be formed in the support member (e.g., an axially-extending commissure post coupled to the frame, an actuator, or a locking mechanism). Alternatively, or additionally, the H-shaped commissure window can be formed by a wireform (e.g., bent piece of wire) or clamp coupled to the frame, actuator, locking mechanism, or support member. Further details regarding commissure windows formed from wireforms and commissure windows formed in or on actuators, locking mechanisms, and support members can be found in <CIT> and International Publication No. <CIT>.

As shown in <FIG>, the prosthetic heart valve <NUM> can also include one or more skirts or sealing members. For example, the prosthetic heart valve <NUM> can include an inner skirt <NUM> mounted on an inner surface of the frame <NUM> and/or an outer skirt <NUM> mounted on an outer surface of the frame <NUM>. The inner skirt <NUM> can be a circumferential inner skirt that spans an entire circumference of the inner surface of the frame <NUM>. The inner skirt <NUM> can function as a sealing member to prevent or decrease perivalvular leakage (e.g., when the valve is placed at the implantation site) and as an attachment surface to anchor a portion of the leaflets <NUM> to the frame <NUM>. For example, the cusp edge portions <NUM> of the leaflets <NUM> (see <FIG>) can be sutured to the inner skirt <NUM>, which in turn can be sutured to selected struts <NUM> of the frame <NUM>. The outer skirt <NUM> can function as a sealing member by sealing against the tissue of the native valve annulus and helping to reduce paravalvular leakage past the prosthetic valve <NUM>. The inner and outer skirts <NUM>, <NUM> can be formed from any of various suitable biocompatible materials, including any of various synthetic materials (e.g., polyethylene terephthalate (PET)) or natural tissue (e.g., pericardial tissue). The inner and outer skirts <NUM>, <NUM> can be mounted to the frame <NUM> using sutures, adhesive, welding, and/or other means for attaching the skirts to the frame. Further details regarding the inner and outer skirts, techniques for assembling the leaflets to the inner skirt, and techniques for assembling the skirts on the frame are disclosed in <CIT>, <CIT>, and <CIT>, and International Patent Application Publication Nos. <CIT> and <CIT> (Application Nos. <CIT> and <CIT>).

Once each commissure <NUM> of the valvular structure <NUM> has been secured to a respective one of the commissure windows <NUM>, the lower edges of the leaflets <NUM> between commissures <NUM> can be sutured to the inner skirt <NUM>. For example, the sutures can be in- and-out sutures extending through each leaflet, inner skirt, and optionally a reinforcing strip (not shown). Each leaflet and respective reinforcing strip can be sewn separately to the inner skirt. In this manner, the lower edges of the leaflets <NUM> can be secured to the frame <NUM> via the inner skirt <NUM>. In some embodiments, the lower edges of the leaflets <NUM> can be secured to the skirt with blanket sutures that extend through each reinforcing strip, leaflet, and the inner skirt while looping around edges of the reinforcing strips and leaflets.

In some embodiments, adjacent leaflet tabs of a commissure can be coupled together prior to insertion through the commissure window. A first leaflet tab of the commissure can be folded and attached to a second leaflet tab, which can remain unfolded. Once the upper and lower tab portions of the first and second leaflet tabs are passed through the upper and lower openings, respectively, to the radially-outer side of the commissure window, one or more wedge members can be inserted between folded portions of the first leaflet tab. Prior to or after insertion of the wedge member(s), the second leaflet tab can be wrapped around the folded first leaflet tab. The wedge member(s) can increase a width of the combination of first and second folded leaflet tabs such that the leaflet tabs cannot pass back through the window.

For example, <FIG> illustrate a first exemplary method of installing a commissure <NUM> to an H-shaped commissure window <NUM>. Referring to <FIG>, a first leaflet tab 162a and a second leaflet tab 162b can be disposed adjacent to each other. The first leaflet tab 162a can have an upper tab portion 164a with free end 172a, a lower tab portion 166a with free end 174a, and a gap 168a with end surface 176a separating the upper and lower tab portions. Similarly, the second leaflet tab 162b can have an upper tab portion 164b with free end 172b, a lower tab portion 166b with free end 174b, and a gap 168b with end surface 176b separating the upper and lower tab portions. Each upper tab portion 162a,b can have a first part 193a,b that is adjacent to a free end 172a,b of the upper tab portion and a second part 191a,b that is between the first part 193a,b and the centerline of the leaflet (or the respective end surface 176a,b of the gap 168a,b along a direction perpendicular to the centerline). Similarly, each lower tab portion 164a,b can have a first part that is adjacent to a free end 174a,b of the lower tab portion and a second part that is between the first part and the centerline of the leaflet (or the respective end surface 176a,b of the gap 168a,b along a direction perpendicular to the centerline).

In some embodiments, each of the upper tab portions 164a,b and the lower tab portions 166a,b can optionally be provided with one or more holes, through which one or more sutures can be passed to couple the tab portions and/or a wedge member together. For example, the first parts 193a of the upper and lower tab portions 164a, 166a of the first leaflet tab 162a can have through-holes 182a, while the second parts 191a of the upper and lower tab portions 164a, 166a of the first leaflet tab 162a can have through-holes 180a. Similarly, the first parts 193b of the upper and lower tab portions 164b, 166b of the second leaflet tab 162b can have through-holes 182b, while the second parts of the upper and lower tab portions 164b, 166b of the second leaflet tab 162b can have through-holes 180b. One or more sutures <NUM> can be passed through the holes 182a in the first leaflet tab 162a and the holes 180b in the second leaflet tab 162b to couple the leaflet tabs 162a,b together. In other embodiments, only some or none of the first and second parts of the tab portions are provided with holes <NUM>, <NUM>. In such embodiments, a suture can pierce through the first or second parts of the leaflet tab portions, or a means for attachment other than a suture can be used to couple the leaflet tab portions together, for example, by welding or adhesive.

As illustrated in <FIG>, the first leaflet tab 162a can be folded onto itself, for example, by passing the free ends 172a, 174a of the upper and lower tab portions 164a, 166a between the first leaflet tab 162a and the second leaflet tab 162b. Thus, the first part 193a of the upper tab portion 164a of the first leaflet tab 162a contacts, or at least faces, the second part 191b of the upper tab portion 164b of the second leaflet tab 162b, and the first part of the lower tab portion 166a of the first leaflet tab 162a contacts, or at least faces, the second part of the lower tab portion 166b of the second leaflet tab 162b. The folded portions of the first leaflet tab 162a also creates a gap or recess <NUM> between the facing surfaces of the first part 193a and second part 193a of the upper tab portion 164a and between the facing surfaces of the first and second parts of the lower tab portion 166a.

In some embodiments, one or more sutures <NUM> can be used to couple the leaflet tabs 162a, 162b together after the folding of the first leaflet tab 162a. Alternatively, the one or more sutures <NUM> can be used to couple the leaflet tabs 162a, 162b together before the folding of the first leaflet tab 162a. For example, the first leaflet tab 162a can be disposed in a substantially flat configuration on the second leaflet tab 162b and extending in an opposite direction from the second leaflet tab 162b, such that the centerlines of the leaflets are on opposite sides of overlapping portions of the first and second leaflet tabs 162a, 162b. Thus, the first parts 193a of the upper and lower tab portions 164a, 166a of the first leaflet tab 162a can be aligned with the second parts 191b of the upper and lower tab portions 164b, 166b of the second leaflet tab 162b, and the first parts 193b of the upper and lower tab portions 164b, 166b of the second leaflet tab 162b can be aligned with the second parts 191a of the upper and lower tab portions 164a, 166a of the first leaflet tab 162a. In this overlapping configuration, the one or more first sutures <NUM> can be passed through the first parts 193a of the upper and lower tab portions 164a, 166a of the first leaflet tab 162a (e.g., via through-holes 182a) and through the second parts 191b of the upper and lower tab portions 164b, 166b of the second leaflet tab 162b (e.g., via through-holes 180b) to couple together the leaflet tabs 162a, 162b. After the leaflet tabs are coupled together, the upper and lower tab portions 164a, 166a can then be folded, as described above. In some embodiments, a single suture <NUM> can be used to couple both the upper and lower tab portions of the first and second leaflet tabs 162a, 162b, so long as the portion of the suture <NUM> extending between the upper tab portions 164a, 164b and the lower tab portions 166a, 166b does not otherwise interfere with crossbar <NUM> as the leaflet tabs 162a, 162b are inserted into the commissure window <NUM>.

With the upper and lower tab portions 164a, 166a of the first leaflet tab 162a folded, the coupled-together first and second leaflet tabs 162a, 162b can then be conveyed from a radially-inner side through respective openings <NUM>, <NUM> to a radially-outer side of the commissure window <NUM>. For example, as shown in <FIG>, the free end 172b of the upper tab portion 166b of the second leaflet tab 162b can be inserted into the upper opening <NUM> of the commissure window, followed by the remainder of the upper tab portion 166b of the second leaflet tab 162b and the folded portions of the upper tab portion 164a of the first leaflet tab 162a. Similarly, the free end 174b of the lower tab portion 166b of the second leaflet tab 162b can be inserted into the lower opening <NUM> of the commissure window, followed by the remainder of the lower tab portion 166b of the second leaflet tab 162b and the folded portions of the lower tab portion 166a of the first leaflet tab 162a. In some embodiments, the insertion of the upper tab portions 164a, 164b into the upper opening <NUM> and the insertion of the lower tab portions 166a, 166b into the lower opening <NUM> can occur simultaneously or substantially at the same time. In other embodiments, the lower tab portions 166a, 166b can be fully inserted through the lower opening <NUM> prior to insertion of the upper tab portions 164a, 164b into the upper opening <NUM>, or vice versa.

Once the upper and lower tab portions of the first and second leaflet tabs 162a, 162b have been inserted through the respective openings <NUM>, <NUM> of the commissure window, one or more wedge members can be added to the assembly at the radially-outer side of the commissure window. For example, a wedge member <NUM> can be inserted into the recess <NUM> formed by the upper and lower tab portions 164a, 166a of the first leaflet tab 162a, as illustrated in <FIG>. The wedge member <NUM> can be conveyed parallel to the axial direction of the frame (e.g., from the outflow end <NUM> to the inflow end <NUM> or vice versa) in between the facing surfaces of the first and second parts 191a, 193a of the upper and lower tab portions 164a, 166a of the first leaflet tab 162a. The wedge member <NUM> can extend between the upper and lower tab portions 164a, 166a and thus prevent, or at least restrain, the leaflet tabs 162a, 162b from passing back through the commissure window <NUM> (e.g., from the radially-outer side of the window back to the radially-inner side of the window) due to interaction between an intermediate portion of the wedge member <NUM> (e.g., between the upper tab portion 164a and the lower tab portion 164b along the axial direction of the frame) and the crossbar <NUM> of the window. The wedge member <NUM> may also cause a width (along the circumferential direction) of the combination of the first and second leaflet tabs 162a, 162b at the radially-outer side of the window <NUM> to be greater than that of the upper opening <NUM> and/or lower opening <NUM>. Thus, the increased width can also prevent, or at least restrain, leaflet tabs 162a, 162b from passing back through the commissure window <NUM>.

Alternatively, multiple wedge members can be provided, for example, a first wedge member for the upper tab portion 164a of the first leaflet tab 162a and a separate second wedge member for the lower tab portion 166a of the first leaflet tab. In such configurations, a gap 168a between the upper tab portion 164a and lower tab portion 166a would remain after insertion of the first and second wedge members. However, each wedge member causes a width (along the circumferential direction) of the combination of the first and second leaflet tabs 162a, 162b at the radially-outer side of the window <NUM> to be greater than that of the upper opening <NUM> and/or lower opening <NUM>, thereby preventing, or at least restraining, the leaflet tabs 162a, 162b from passing back through the commissure window <NUM>. In such embodiments, the multiple wedge members can be coupled together (e.g., via stitching using one or more sutures) and/or the upper and lower tab portions on the radially-outer side of the commissure window <NUM> can be coupled together (e.g., via stitching using one or more sutures), for example, to prevent sliding along the axial direction of the respective tab portions.

Once the one or more wedge members have been positioned with respect to the first leaflet tab 162a, the upper tab portion 164b of the second leaflet tab 162b can be wrapped around the upper tab portion 164a of the first leaflet tab 162a, as shown in <FIG>. Before, during, or after the wrapping of the upper tab portion 164b, the lower tab portion 166b of the second leaflet 162b can also be wrapped around the lower tab portion 166a of the first leaflet tab 162a. Alternatively, in some embodiments, the upper tab portion 164b and/or the lower tab portion 166b of the second leaflet tab 162b can be wrapped around the respective tab portions of the first leaflet tab 162a prior to positioning of the wedge members. In either case, after positioning of the one or more wedge members, the tab portions of each leaflet tab 162a, 162b can be arranged such that free ends 172a, 172b of the upper tab portions 164a, 164b and free ends 174a, 174b of the lower tab portions 166a, 166b are disposed between the wedge member <NUM> and a radially-outer side of the commissure window <NUM> along a radial direction of the frame <NUM>.

One or more sutures can be used to couple together the wedge members and the folded leaflet tabs 162a, 162b. For example, one or more second sutures <NUM> can be passed through the first part 193b of the upper tab portion 164b of the second leaflet tab 162b (e.g., via through-holes 182b), the second part 191a of the upper tab portion 164a of the first leaflet tab 162a (e.g., via through-holes 180a), the wedge member <NUM>, the first part 193a of the upper tab portion 164a of the first leaflet tab 162a (e.g., via through-holes 182a), and the second part 191a of the upper tab portion 164b of the second leaflet tab 162b (e.g., via through-holes 180b), in order or vice versa. The one or more second sutures <NUM> can be passed through the first and second parts of the lower tab portions 166a, 166b of the first and second leaflet tabs 162a, 162b and the wedge member <NUM> in a similar manner.

If the valvular structure includes other commissures to be attached to commissure windows of the frame, the method of <FIG> can be repeated for the other commissures. In some embodiments, the valvular structure can have a tricuspid configuration with three leaflets, and the three commissures of the valvular structure are coupled to respective commissure windows of the frame by performing the method of <FIG> three separate times. In other embodiments, the valvular structure can have a bicuspid configuration with two leaflets, and the two commissures of the valvular structure are coupled to respective commissure windows of the frame by performing the method of <FIG> two separate times. In any of the embodiments with multiple commissures and commissure windows, performance of some or all of the method for the respective commissures can occur in parallel. For example, the leaflet tabs for each commissure can be folded and coupled together at the same time, after which the coupled leaflet tabs can be inserted into their respective windows. Other variations for parallel assembly of multiple commissures to multiple commissure windows are also possible according to one or more contemplated embodiments.

The method of assembly described with respect to <FIG> provides a simple and cost-effective methodology for installing commissure assemblies to respective windows of the valve frame. For example, the configuration of <FIG> can allow the leaflet tabs 162a, 162b to be quickly and easily coupled together in a flat configuration, followed by a simple sliding/insertion of the upper and lower tab portions into the respective upper and lower openings of the commissure window. Moreover, the assembly of the leaflet tabs and subsequent mounting to the window using one or more wedge members involves a relatively small number of distinct components and assembly stages.

In some embodiments, adjacent leaflet tabs of a commissure can be inserted through the commissure window prior to any folding of the leaflet tabs and/or the coupling of leaflet tabs to each other. The upper and lower tab portions of the first and second leaflet tabs are passed (simultaneously or sequentially) through the upper and lower openings, respectively, to the radially-outer side of the commissure window. The first leaflet tab can then be folded around one or more wedge members and coupled thereto. Prior to or after the coupling of the first leaflet tab and the wedge member(s), the second leaflet tab can be wrapped around the folded first leaflet tab. The wedge member(s) can increase a width of the combination of first and second folded leaflet tabs such that the leaflet tabs cannot pass back through the window.

For example, <FIG> illustrate a second exemplary method of installing a commissure <NUM> to an H-shaped commissure window <NUM>. While <FIG> illustrate only the upper tab portions 164a, 164b of the first and second leaflet tabs 162a, 162b, it should be noted that the installation of the lower tab portions 166a, 166b of the first and second leaflet tabs 162a, 162b would be handled in a similar manner simultaneously with, or substantially at a same time as, the illustrated installation of the upper tab portions 164a, 164b.

In <FIG>, a first leaflet tab 162a and a second leaflet tab 162b can be disposed adjacent to each other. As described in detail above, each leaflet tab 162a, 162b can have respective upper tab portions 164a, 164b and lower tab portions 166a, 166b separated by a gap 168a, 168b. Each upper tab portion 162a,b can have a first part 193a,b that is adjacent to a free end 172a,b of the upper tab portion and a second part 191a,b that is between the first part 193a,b and the centerline of the leaflet, and each lower tab portion can have a first part that is adjacent to a free end of the lower tab portion and a second part that is between the first part and the centerline of the leaflet. In some embodiments, the respective first and second parts of the upper tab portions 164a,b and the lower tab portions 166a,b can optionally be provided with one or more holes (e.g., through-holes 180a,b and 182a,b), through which one or more sutures can be passed to couple the tab portions and/or a wedge member together.

The first leaflet tab 162a can be conveyed from a radially-inner side through respective openings <NUM>, <NUM> to a radially-outer side of the commissure window <NUM>. Before, after, or during the conveying of the first leaflet tab 162a into commissure window <NUM>, the second leaflet tab 162b can be conveyed from the radially-inner side through respective openings <NUM>, <NUM> to the radially-outer side of the commissure window <NUM>. For example, as shown in <FIG>, the free end 172a of the upper tab portion 164a of the first leaflet tab 162a can be inserted into the upper opening <NUM> of the commissure window, and the free end 172b of the upper tab portion 164b of the second leaflet tab 162b can be inserted into the upper opening of the commissure window. Similarly, the free end 174a of the lower tab portion 166a of the first leaflet tab 162a can be inserted into the lower opening <NUM> of the commissure window, and the free end 174b of the lower tab portion 166b of the second leaflet tab 162b can be inserted into the lower opening of the commissure window. In some embodiments, the insertion of the upper tab portions 164a, 164b into the upper opening <NUM> and the insertion of the lower tab portions 166a, 166b into the lower opening <NUM> can occur simultaneously or substantially at the same time. In other embodiments, the lower tab portions 166a, 166b can be fully inserted through the lower opening <NUM> prior to insertion of the upper tab portions 164a, 164b into the upper opening <NUM>, or vice versa.

After insertion through respective openings <NUM>, <NUM> of the commissure window <NUM>, the first leaflet tab 162a can be wrapped around one or more wedge members at the radially-outer side of the commissure window. For example, the upper and lower tab portions 164a, 166a of the first leaflet tab 162a can be wrapped around (e.g., folded around) a single wedge member <NUM>, as illustrated in <FIG>. The wedge member <NUM> can extend between the upper and lower tab portions 164a, 166a and thus prevent, or at least restrain, the leaflet tabs 162a, 162b from passing back through the commissure window <NUM> (e.g., from the radially-outer side of the window back to the radially-inner side of the window) due to interaction between an intermediate portion of the wedge member <NUM> (e.g., between the upper tab portion 164a and the lower tab portion 164b along the axial direction of the frame) and the crossbar <NUM> of the window. The wedge member <NUM> may also cause a width (along the circumferential direction) of the combination of the first and second leaflet tabs 162a, 162b at the radially-outer side of the window <NUM> to be greater than that of the upper opening <NUM> and/or lower opening <NUM>. Thus, the increased width can also prevent, or at least restrain, leaflet tabs 162a, 162b from passing back through the commissure window <NUM>.

One or more sutures can be used to couple together the wedge members and the wrapped upper and lower tab portions 164a, 166a of the first leaflet tab 162a. For example, as illustrated in <FIG>, one or more first sutures <NUM> can be passed through the first part 193a of the upper tab portion 164a of the first leaflet tab 162a (e.g., via through-hole 182a), the wedge member <NUM>, and the second part 191a of the upper tab portion 164a of the first leaflet tab 162a (e.g., via through-hole 180a), in order or vice versa. The one or more first sutures <NUM> can be passed through the first and second parts of the lower tab portion 166a of the first leaflet tab 162a in a similar manner.

One or more sutures can be used to couple together the wedge members and the wrapped leaflet tabs 162a, 162b. For example, as illustrated in <FIG>, one or more second sutures <NUM> can be passed, through the first part 193b of the upper tab portion 164b of the second leaflet tab 162b (e.g., via through-holes 182b), the second part 191a of the upper tab portion 164a of the first leaflet tab 162a (e.g., via through-holes 180a), the wedge member <NUM>, the first part 193a of the upper tab portion 164a of the first leaflet tab 162a (e.g., via through-holes 182a), and the second part 191a of the upper tab portion 164b of the second leaflet tab 162b (e.g., via through-holes 180b), in order or vice versa. The one or more second sutures <NUM> can be passed through the first and second parts of the lower tab portions 166a, 166b of the first and second leaflet tabs 162a, 162b and the wedge member <NUM> in a similar manner. In some embodiments, the second leaflet tab 162b can be wrapped around the first leaflet tab 162a and the one or more wedge members prior to coupling the first leaflet tab 162a to the wedge member(s) <NUM>. In such embodiments, the first suture(s) <NUM> can be omitted in favor of coupling together the first and second leaflet tabs 162a, 162b and the wedge member(s) <NUM> using just the second suture(s) <NUM>.

If the valvular structure includes other commissures to be attached to commissure windows of the frame, the method of <FIG> can be repeated for the other commissures. In some embodiments, the valvular structure can have a tricuspid configuration with three leaflets, and the three commissures of the valvular structure are coupled to respective commissure windows of the frame by performing the process of <FIG> three separate times. In other embodiments, the valvular structure can have a bicuspid configuration with two leaflets, and the two commissures of the valvular structure are coupled to respective commissure windows of the frame by performing the method of <FIG> two separate times. In any of the embodiments with multiple commissures and commissure windows, performance of some or all of the method for the respective commissures can occur in parallel. For example, the leaflet tabs for each commissure can be inserted into their respective windows and then the first leaflet tabs can be wrapped around and coupled to respective wedge members. Other variations for parallel assembly of multiple commissures to multiple commissure windows are also possible according to one or more contemplated embodiments.

The method of assembly described with respect to <FIG> provides a simple and cost-effective methodology for installing commissure assemblies to respective windows of the valve frame. For example, the arrangement of <FIG> can allow the leaflet tabs 162a, 162b to be quickly and easily inserted through the respective upper and lower openings of the commissure window. Moreover, the assembly of the leaflet tabs and subsequent mounting to the window using one or more wedge members involves a relatively small number of distinct components and assembly stages.

In some embodiments, upper and lower tab portions of adjacent leaflet tabs can be coupled to separate wedge members prior to insertion through the commissure window. For example, an upper tab portion of the first leaflet tab of the commissure can be wrapped around a first wedge member, and then coupled to an upper tab portion of the second leaflet tab, which remains unfolded. Similarly, a lower tab portion of the first leaflet tab of the commissure can be wrapped around a second wedge member, and then coupled to a lower tab portion of the second leaflet tab, which remains unfolded. The configuration for upper and lower tab portions can be similar to that illustrated in <FIG>, but with upper tab portion having a wedge member <NUM> separate from that of the lower tab portion.

The cross-sectional dimension of each wedge member can be such that the combination of wrapped upper tab portion of the first leaflet tab, first wedge member, and unfolded upper tab portion of the second leaflet tab fits through the upper opening of the commissure window, and the combination of wrapped lower tab portion of the first leaflet tab, second wedge member, and unfolded lower tab portion of the second leaflet tab fits through the lower opening of the commissure window. Since there is no wedge member extending between the upper and lower tab portions that would otherwise obstruct passage of the commissure through the window due to crossbar <NUM>, the upper and lower tab portions of the first and second leaflet tabs can be passed through the upper and lower openings of the commissure window, respectively, from the radially-inner side to the radially-outer side of the commissure window.

The second leaflet tab can then be wrapped around and further coupled to the first leaflet tab and the wedge members, resulting in a structure similar to that described above with respect to <FIG>, <FIG>, or <FIG>. Each wedge member can increase a width of the combination of the wrapped first and second leaflet tabs such that the leaflet tabs is prevented, or at least restrained, from passing back through the window. In such embodiments, the multiple wedge members can be coupled together (e.g., via stitching using one or more sutures) and/or the upper and lower tab portions on the radially-outer side of the commissure window <NUM> can be coupled together (e.g., via stitching using one or more sutures), for example, to prevent sliding along the axial direction of the respective tab portions. As with the other described embodiments, if the valvular structure includes other commissures to be attached to commissure windows of the frame, the method can be repeated for the other commissures.

In some embodiments, the upper tab portion of the first and second leaflet tabs can be inserted through the upper opening and attached to the commissure window <NUM> and/or the lower tab portion of the first and second leaflet tabs can be inserted through the lower opening and attached to the commissure window <NUM>, using any of the assembly techniques disclosed in <CIT>.

In some embodiments, the leaflet tabs of each leaflet of the valvular structure can be formed without separate upper and lower tab portions, for example, without gaps <NUM>. In such embodiments, the leaflet tabs can have a configuration similar to those described in <CIT> and the other applications and publications. In some embodiments, these leaflet tabs can be inserted into either the upper opening or the lower opening of the commissure window <NUM>. Since the leaflet tabs are only inserted into half of the H-shaped commissure window <NUM>, the commissure window <NUM> may be considered a U-shaped window in such embodiments.

In any of the disclosed examples or embodiments, a coupling member, such as a flexible cloth or fabric, can be disposed around surfaces of the leaflet tabs and or the wedge member(s). For example, the coupling member can be attached to the wedge member(s) and the tabs prior to installation in the commissure window. In some embodiments, the coupling member can be wrapped around portions of the commissure window (e.g., struts <NUM>, <NUM>) to further secure the leaflet tabs to the commissure window and/or protect portions of the leaflets from abrasion.

<FIG> illustrate an alternative frame <NUM>' with commissure windows <NUM>' according to another example. In some embodiments, the prosthetic valve <NUM> can include the frame <NUM>' instead of the previously described frame <NUM>. The frame <NUM>' is similar in many respects to the frame <NUM> except for the details of the commissure windows. Similar reference numbers are used for parts of the frame <NUM>' that are similar or the same as parts of the frame <NUM>. For purposes of illustration, only the bare frame <NUM>' is shown in <FIG>. It should be understood that any of the other components of the prosthetic valve <NUM> (e.g., leaflets <NUM>, inner skirt <NUM>, outer skirt <NUM>, etc.) can be assembled onto the frame <NUM>' in the manner shown in <FIG> and described above.

In the example illustrated in <FIG>, each commissure window <NUM>' can include window struts <NUM>, <NUM>, which extend along the axial direction of the frame <NUM>' and are spaced along the circumferential direction of the frame <NUM>'. Each commissure window <NUM>' can include a crossbar <NUM> extending between and connected to the window struts <NUM>, <NUM>. Each commissure window <NUM>' can include a first, upper opening <NUM> (or upper window portion or downstream window portion) formed on one side of the crossbar <NUM> and a second, lower opening <NUM> (or lower window portion or upstream window portion) formed on the other side of the crossbar <NUM>.

Each commissure window <NUM>' can further include an upper lateral strut portion <NUM> extending between the upper ends of the window struts <NUM>, <NUM> and forming a closed end of the upper opening <NUM>. In one example, an upper angled strut 130a is connected to an upper end of the window strut <NUM>, and an upper angled strut 130b is connected to an upper end of the window strut <NUM>. The upper lateral strut portion <NUM> extends between the junction formed between the upper angled strut 130a and the window strut <NUM> and the junction formed between the upper angled strut 130b and the window strut <NUM>. The upper lateral strut portion <NUM> can thereby increase the stability of the window struts <NUM>, <NUM> at the upper ends.

Each commissure window <NUM>' can further include a lower lateral strut portion <NUM> extending between the lower ends of the window struts <NUM>, <NUM> and forming a closed end of the lower opening <NUM>. In one example, a lower angled strut 132a is connected to a lower end of the window strut <NUM>, and a lower angled strut 132b is connected to a lower end of the window strut <NUM>. The lower lateral strut portion <NUM> extends between the junction formed between the lower angled strut 132a and the window strut <NUM> and the junction formed between the lower angled strut 132a and the window strut <NUM>. The lower lateral strut portion <NUM> can thereby increase the structural stability of the window struts <NUM>, <NUM> at the lower ends.

The lateral strut portions <NUM>, <NUM> are spaced in the axial direction of the frame <NUM>' and extend in the circumferential direction of the frame <NUM>'. The upper opening <NUM> is enclosed by the window struts <NUM>, <NUM>, the upper lateral strut portion <NUM>, and the crossbar <NUM>. The lower opening <NUM> is enclosed by the window struts <NUM>, <NUM>, the lower lateral strut portion <NUM>, and the crossbar <NUM>. The resulting commissure window <NUM>' can be described as having an H-shape with closed ends, where the window struts <NUM>, <NUM> and the crossbar <NUM> form the H-shape (as in the previously described commissure window <NUM>) and the lateral strut portions <NUM>, <NUM> form the closed ends.

The inner surface 131a of the upper lateral strut portion <NUM> that faces the upper opening <NUM> can be flat as shown, or it can be curved (e.g., concave) in other examples. The outer surface 131b of the upper lateral strut portion <NUM> that extends between the upper angled struts 131a, 131b can be curved. In some cases, the outer surface 131b may include a notch (e.g., a U-shaped notch), as shown, for example, at the ends of the struts <NUM>. The inner surface 133a of the lower lateral strut portion <NUM> that faces the opening <NUM> can be flat as shown, or it can be curved (e.g., concave) in other examples. The outer surface 133b of the lateral strut portion <NUM> that extends between the lower angled struts 132a, 132b can be curved. In some cases, the outer surface 133b may include a notch (e.g., U-shaped notch), as shown, for example, at the ends of the struts <NUM>.

An axial distance measured from the inner surface 131a of the upper lateral strut portion <NUM> to a midline of the crossbar <NUM> can be represented by the length L<NUM>. An axial distance measured from the inner surface 133a of the lower lateral strut portion <NUM> to the midline of the crossbar <NUM> can be represented by the length L<NUM>. The axial distance measured from the inner surface 131a of the upper lateral strut portion <NUM> to the inner surface 133a of the lower lateral strut portion <NUM> can be represented by the length L, which is the sum of the lengths L<NUM> and L<NUM>. The thickness of the crossbar <NUM> in the axial direction can be represented by the length L<NUM>.

The ratio L<NUM>/L<NUM> determines the axial position of the crossbar <NUM> relative to the window struts <NUM>, <NUM> (or the relative to the lateral strut portions <NUM>, <NUM>). In one example, the ratio L<NUM>/L<NUM> can be greater than or equal to <NUM>. When L<NUM>/L<NUM> is equal to <NUM>, the crossbar <NUM> is positioned at the midpoint of each window strut <NUM>, <NUM> along the axial direction. When L<NUM>/L<NUM> is greater than <NUM>, the upper opening <NUM> is taller than the lower opening <NUM>, and the crossbar <NUM> is positioned closer to the lower lateral strut portion <NUM> than to the upper lateral strut portion <NUM>. L<NUM>/L<NUM> greater than <NUM> may allow the commissure window <NUM>' to carry a higher load in the upper window portion. In one example, L<NUM>/L<NUM> can be in a range from <NUM> to <NUM>.

The length of the upper opening <NUM> is L<NUM> - ½ L<NUM>. The length of the lower opening <NUM> is L<NUM> - ½ L<NUM>. The leaflets can experience greater stress along the upper opening <NUM> since the leaflet free edge (i.e., the edge of the leaflet that coapts with the free edges of the other leaflets to close the prosthetic valve and moves away from the free edges of the other leaflets to open the prosthetic valve) is attached to this opening. In some cases, a longer L<NUM> can help prevent tearing at the portion of the commissure formed in the upper opening <NUM>. In other cases, a longer L<NUM> can allow use of a high tab, which is a commissure tab that is slightly higher than the leaflet outflow. A high tab can allow better stress distribution at the top of the commissure.

<FIG> illustrates an example of a leaflet <NUM> with a relatively high commissure tab. The leaflet <NUM> can include a main, cusp edge portion <NUM>, two leaflet tabs <NUM> (or commissure tabs), and a leaflet free edge <NUM> (or coaptation edge). In the orientation of the drawing, the cusp edge portion <NUM> forms a lower edge portion of the leaflet <NUM>, and the leaflet free edge <NUM> forms an upper edge of the leaflet <NUM>. The leaflet tabs <NUM> project from opposite side edges of the leaflet <NUM>. In some cases, the leaflet tabs <NUM> can be symmetrical about a centerline <NUM> of the leaflet. Each of the tabs <NUM> can include an upper tab portion <NUM> and a lower tab portion <NUM> separated by a notch <NUM> (or slit). In one example, the height Z<NUM> of each upper tab portion <NUM> can be greater than the height Z<NUM> of the respective lower tab portion <NUM>. In one example, the upper tab portions <NUM> can extend slightly above the leaflet free edge <NUM> by a height Z<NUM> > <NUM>. For example, height Z<NUM> can be in a range from <NUM> to <NUM>.

A leaflet assembly composed of a plurality of leaflets <NUM> (e.g., three leaflets <NUM>) can be coupled to an annular frame using the commissure windows <NUM>' (shown in <FIG>). The assembly can include extending the high upper tab portions <NUM> of adjacent leaflets <NUM> through the upper openings <NUM> of the commissure windows <NUM>' to form upper portions of the commissures and extending the lower tab portions <NUM> through the lower openings <NUM> of the commissure windows <NUM>' to form the lower portions of the commissures. The process of forming the commissures can be as previously described with respect to commissure window <NUM>. In the example where the upper tab portions <NUM> extend above the leaflet free edge <NUM>, as shown in <FIG>, bumps will be formed at the entrance of the commissure windows <NUM>'. These bumps can allow better stress distribution at the top of the commissures formed at the commissure windows <NUM>' by the leaflet tabs <NUM>.

Returning to <FIG>, the length L<NUM> (i.e., the thickness of the crossbar <NUM> in the axial direction) is normally significantly less than each of lengths L<NUM> and L<NUM>. At the same time, the length L<NUM> should be large enough to provide the crossbar <NUM> with sufficient strength to prevent the window struts <NUM>, <NUM> from buckling too much under load. The length L<NUM> can be determined by analysis of the forces acting on the commissure window <NUM>' during transition of the frame <NUM>' from the crimped configuration to the fully expanded configuration. In one example, the length L<NUM> can have a minimum value of <NUM>. In another example, the length L<NUM> can have a minimum value of <NUM>.

The minimum thickness of the lateral strut portion <NUM> in the axial direction can be represented by the length L<NUM>, and the minimum thickness of the lateral strut portion <NUM> in the axial direction can be represented by the length L<NUM>. The lengths L<NUM> and L<NUM> can be the same or can be different, and each length L<NUM>, L<NUM> should be large enough to provide the respective lateral strut portion with sufficient strength to prevent the window struts <NUM>, <NUM> from buckling too much under load. The lengths L<NUM> and L<NUM> can be determined by analysis of the forces acting on the commissure window <NUM>' during transition of the frame <NUM> from the crimped configuration to the fully expanded configuration. In one example, each of the lengths L<NUM> and L<NUM> can have a minimum value of <NUM>. In another example, each of the lengths L<NUM> and L<NUM> can have a minimum value of <NUM>.

The openings <NUM>, <NUM> (or the gap between the window struts <NUM>, <NUM>) can have a width W<NUM>. The size of the width W<NUM> can be selected to accommodate two leaflet tabs, sutures, and/or fabric involved in forming commissures, while taking into account compression of the leaflet tabs. In one example, the width W<NUM> can be in a range from <NUM> to <NUM>. The width of the window struts <NUM>, <NUM> can be represented by W<NUM>. The width W<NUM> is selected based on strength considerations. In one example, the width W<NUM> is selected such that the window struts <NUM>, <NUM> do not bend during crimping/expansion and during cycling. The size of the width W<NUM> can be determined by force analysis (e.g., using finite element analysis) of the frame <NUM>' when the frame <NUM>' transitions between the crimped and fully expanded configurations and when the leaflets of the valvular structure attached to the frame are cycling between open and closed potions. In one example, the width W<NUM> can be in a range from <NUM> to <NUM>.

The crossbar <NUM> and the lateral strut portions <NUM>, <NUM> can enable the commissure window <NUM>' to be elongated in form. Elongated commissure windows can accommodate longer leaflet tabs (the length being measured in the axial direction), which are useful in relieving stresses applied to the leaflets during the transition between the systolic and diastolic phases. The crossbar <NUM> divides the commissure window into sub-windows such that the window strut portions of each sub-window extend over a shorter length, allowing the sub-window to retain its structural integrity and resist bending/plastic deformation under load, such as when the prosthetic valve is crimped to a radially compressed state. The lateral strut portions <NUM>, <NUM> affixed to the ends of the window struts <NUM>, <NUM> advantageously increase the structural stability of the window struts <NUM>, <NUM>.

Claim 1:
A prosthetic heart valve (<NUM>) comprising:
an expandable annular frame (<NUM>) having a plurality of commissure windows (<NUM>); and
a valvular structure (<NUM>) comprising a plurality of leaflets (<NUM>), each leaflet having a pair of tabs (<NUM>), one of the tabs (<NUM>) being on an opposite side from the other of the tabs (<NUM>) with respect to a centerline of the leaflet, each tab having an upper tab portion (<NUM>) and a lower tab portion (<NUM>);
wherein the valvular structure (<NUM>) has a plurality of commissures (<NUM>) formed by paired tabs (<NUM>) of adjacent leaflets (<NUM>), each commissure being coupled to a corresponding one of the commissure windows (<NUM>) to support the valvular structure (<NUM>) within the annular frame (<NUM>);
wherein each commissure window (<NUM>) has upper and lower openings (<NUM>, <NUM>) separated from each other along an axial direction of the annular frame (<NUM>) by a respective crossbar (<NUM>);
wherein the upper and lower tab portions (<NUM>, <NUM>) for each tab extend through the upper and lower openings (<NUM>, <NUM>), respectively, to a radially-outer side of the respective commissure window (<NUM>); and
wherein the annular frame (<NUM>) is expandable between a crimped state having a first diameter (D<NUM>) and an expanded state having a second diameter (D<NUM>) greater than the first diameter (D<NUM>).