Patent Description:
The application relates to prosthetic heart valves, and to associated systems and methods.

Current designs of a mechanical frame for a prosthetic heart valve include a plurality of crossing struts, attached to each other at junctions and forming a grid. The grid of struts forms the wall of the frame that is essentially cylindrical but may vary from a perfect cylinder per any specific frame design. This grid has two layers of struts -- radially inner layer and radially outer layer. All struts in each layer are essentially parallel to each other and cross the struts of the other layer. All inner faces of the inner layer struts form the inner diameter face of the frame. All outer faces of the outer layer struts form the outer diameter face of the frame.

<CIT> discloses a prosthetic heart valve comprising an annular frame with pivoting struts.

Described herein are examples of prosthetic valves, components thereof, and related methods of assembling, delivering, and using the same. Prosthetic valves disclosed herein can be implanted within any of the native valves of the heart (e.g., the aortic, mitral, tricuspid and pulmonary valves). In some embodiments, the prosthetic valve can be delivered through the vasculature and implanted to the heart of a patient by using a delivery apparatus, such as a catheter-based delivery apparatus. Frames disclosed herein may also be used for prosthetic valves in other conduits of the body, or as stents without a valve structure.

The invention is directed to a prosthetic heart valve comprising a radially expandable and compressible annular frame as set out in claim <NUM>, a mechanical frame for a prosthetic valve as set out in independent claim <NUM>, a method of forming a mechanical frame for a prosthetic valve as set out in claim <NUM> and a method of radially compressing a prosthetic heart valve as set out in claim <NUM>.

Certain embodiments of the disclosure concern a prosthetic heart valve. The assembly can include a radially expandable and compressible annular frame. The frames can be expanded within an implant location by applying radially outward forces on the frame, such as by a balloon or mechanical means, or by applying circumferential separation forces on the frame, or by applying axial shortening forces on the frame.

The frame can include a plurality of interconnected struts. The plurality of interconnected struts can include a plurality of inner struts and a plurality of outer struts. The inner struts can overlap adjacent outer struts at a plurality of pivot joints, coupled together with pins or other fasteners that permit the struts to pivot relative to each other. The interconnected struts can be arrayed in a lattice or grid, which each strut extending diagonally or helically around the frame. Radial expansion or compression of the annular frame can cause the inner struts to pivot relative to the outer struts at the pivot joints.

More details regarding the general structure of such prosthetic valve assemblies and mechanical frames can be found in <CIT>. With reference to <CIT>, <FIG> shows an entire prosthetic valve using a mechanical frame comprising interconnected struts pivotably coupled at pivot joints, <FIG> show just the frame and illustrate the radially expanded and compressed configurations, <FIG> show examples of how other components are attached the frame, and <FIG> and <FIG> show individual struts, and FIG. 6C shows a pivot joint in detail. Other components and details of the valves and frames are also described in <CIT>, such as the valve leaflets, inner skirts, outer skirts, frame expansion mechanisms, delivery devices, exemplary materials and dimensions, and related methods of assembly and use. The valves and frames disclosed herein can have an analogous structure to those illustrated in <CIT>, except as described herein. Further details regarding transcatheter prosthetic heart valves, including the manner in which the valvular structure can be mounted to the frame of the prosthetic valve can be found, for example, in <CIT><CIT><CIT><CIT>, and <CIT>, and <CIT>. Further details regarding the construction of frames and the prosthetic valves are described in <CIT>and <CIT>, and <CIT>and <CIT>.

In embodiments disclosed herein, at least some of the struts comprise recessed portions at the pivot joints and segments of others of the struts are seated in the recessed portions at the pivot joints. In some embodiments, at least some of the outer struts comprise recessed portions and segments of at least some of the inner struts are seated in the recessed portions, and in some embodiments at least some of the inner struts comprise recessed portions and segments of at least some of the outer struts are seated in the recessed portions. In some embodiments, at least some of the inner struts comprise recessed portions that receive segments of the outer struts and at least some of the outer struts comprise recessed portions that receive segments of the inner struts.

The pivot joints where the segments are seated in the recessed portions can be configured such that they have a generally continuous inner or outer surface, which can facilitate attachment of leaflets or skirts to the frame and provide other benefits. In some embodiments, the pivot joints where the segments are seated in the recessed portions have a generally continuous inner surface, such that inner surfaces of the seated segments and adjacent inner surfaces the struts joined to the seated segments have about equal radial dimensions from a centerline of the frame. This can help with attachment of the leaflets and inner skirt to the inside of the frame. In some embodiments, the pivot joints where the segments are seated in the recessed portions have a generally continuous outer surface, such that outer surfaces of the seated segments and adjacent outer surfaces the struts joined to the seated segments have about equal radial dimensions from a centerline of the frame. This can help with attachment of an out skirt and/or help prevent perivalvular leakage.

The struts can comprise multiple recessed portions located at respective pivot joints and segments of all the crossing struts can be seated in the recessed portions at the respective pivot joints.

The recesses defined by the recessed portions can be sized to receive the crossing strut segments while allowing for pivoting motion between the struts. The recesses of the recessed portions can have a radial depth that is about equal to the radial thickness of the segments seated in the recessed portions, such that their radially facing surfaces can be flush or coplanar, providing a continuous overall frame surface. The recesses of the recessed portions can have a length that is greater that a width of the segments seated in the recessed portions to allow room for the seated segments to pivot within the recesses.

Also disclosed herein are methods of forming a mechanical frame by coupling inner struts to outer struts at pivot joints, such as via pivot pins. Also disclosed herein are methods of crimping or radially compressing a prosthetic heart valve including a mechanical frame wherein the struts move closer to parallel with the axial dimension in the same circumferential plane such the scissor-like shearing of the valve structure within can be avoided. Also disclosed herein are methods of implanting a prosthetic heart valve wherein the mechanical frame is radially expanded and presses evenly against surrounding native tissue to prevent paravalvular leakage paths between the frame and the native tissue.

More details of the disclosed technology are described below and with reference to the attached drawings.

Described herein are examples of prosthetic heart valves that can be implanted within any of the native valves of the heart (e.g., the aortic, mitral, tricuspid and pulmonary valves). The present disclosure also provides frames for use with such prosthetic implants. Prosthetic valves disclosed herein can be radially compressible and expandable between a radially compressed state and a radially expanded state. Thus, the prosthetic valves can be retained by an implant delivery apparatus in the radially compressed state during delivery, and then expanded to the radially expanded state once the prosthetic valve reaches the implantation site.

Conventional designs of a mechanical frame for a prosthetic heart valve present several disadvantages, which can include some or all of the following, among others: (<NUM>) Each leaflet can be connected to an inner strut at one edge, and to an outer strut at its other edge. The edge of the leaflet connected to the inner strut can be attached to a uniform surface, while the edge connected to an outer strut is on a non-uniform surface (e.g., "zig-zags" along a changing diameter relative to the center of the frame, since it must "climb" over the crossing inner struts). Such a pattern can affect the accuracy and uniformity of leaflet attachment because: (a) it can create folds in the leaflet that alter its shape and interfere with its motion ability, and (b) attachment to different diameters can create asymmetric leaflets such that leaflets coaptation is less than optimal. (<NUM>) The total wall thickness of the frame can be equal to or greater than twice the thickness of a strut, which is a significant factor in crimping. (<NUM>) During the process of crimping, the relative movement between adjacent inner and outer struts exerts scissor-like shearing forces that can compromise the integrity of the leaflet tissue. (<NUM>) In designs that do not include an outer cloth component or a perivalvular seal component, it is likely to result in the parallel outer struts forming channels of perivalvular leakage.

This application discloses a new strut geometry that can avoid the above disadvantages. Valve frames disclosed herein can include struts that have recessed intermediate segments that are configured to accommodate a respective straight intermediate segment of an adjacent crossing strut. Junctions between the crossing struts may bulge along only one surface (outer or inner) of the frame, while the opposite surface remains relatively flat or continuous.

Determination of which surface is provided as a flat/continuous surface, either the inner surface of the frame (interfacing with the leaflets) or the outer surface (interfacing with the anatomic surrounding), can be based on the arrangement of the crossing struts. In some embodiments, the outer struts can be formed with recessed intermediate segments, overlaid over "straight" inner struts, so as to form an inner continuous surface, thereby enabling both edges of the leaflets to attach to continuous inner surfaces of an equal diameter. In other embodiments, the inner struts can be formed with recessed intermediate segments, overlaid over "straight" outer struts, so as to form an outer continuous surface, thereby enabling providing additional free luminal volume in the crimped frame, to accommodate inner soft components.

Recessed portions of a strut can be formed by punching a straight strut at the desired regions. Both geometries (of a continuous outer surface or a continuous inner surface) can provide a tight interface with the anatomy of the blood vessel's wall, resulting in a one layer grid that does not form leak channels.

<FIG> show a frame <NUM> of a prosthetic heart valve comprising a plurality of interconnected struts 40a, 40b, 40c, 40d, etc. <FIG> show schematic representations of the frame <NUM>. The struts each include a plurality of segments disposed between two end portions thereof, and intermediate segments 42a, 42b, etc. disposed between each couple of adjacent segments in a strut. The end portions and the intermediate segments of each strut can comprise apertures, through which the struts can be connected to each other, for example via fasteners such as pins passing through the apertures, to form pivot junctions J1, J2, etc. As can be seen in <FIG>, the width of the junctions J1, J2 is twice the width of a single strut, and the resulting frame geometry forms uneven outer and/or inner surfaces, wherein the junctions bulge radially relative to the straight segments of the struts. <FIG> illustrates how the frame bulges at junctions J1, J2, J3.

<FIG> show a valve leaflet <NUM> attached to a skirt portion or a cloth at scallop suture line <NUM>, and an outer skirt <NUM>, wherein the leaflet <NUM> and the outer skirt <NUM> are attached to an outer strut 40a of the frame <NUM> via suture loops 32a, 32b, etc., and wherein the leaflet <NUM> contacts an inner surface of the frame <NUM> and the outer skirt <NUM> contacts an outer surface of the frame <NUM>. <FIG> shows an example of an overlapping outer strut 40a and inner strut 40b, connected to each other at a junction J1, such that the junction J1 bulges radially inwards, i.e. towards a centerline <NUM> (see <FIG>) of the frame <NUM>. An edge of the leaflet <NUM> is attached via suture loops 32a, 32b to the outer strut 40a, and the radial inward bulging of junction J1 between the suture loops 32a and 32b forms a noncontinuous interface between the leaflet <NUM> and the strut 40a.

<FIG> shows an example of overlapping inner strut 40c and outer strut 40d connected to each other at a pivot junction J2, such that the junction J2 bulges radially outwards. An edge of the leaflet <NUM> is attached via suture loops 32c, 32d to the inner strut 40c, and a continuous interface is formed between the leaflet <NUM> and the strut 40a at this region. However, the radially outward bulging of junction J2 between the suture loops 32c and 32d creates a non-continuous interface between the outer skirt <NUM> and the strut 40c.

<FIG> shows a further challenge of the structure of the frame <NUM>, wherein during crimping of the frame <NUM>, the position of adjacent struts <NUM>, such as struts 40f, <NUM>, <NUM>, 40i, may change such that they approach each other while the frame <NUM> is compressed or crimped, thereby creating undesired folds of either the leaflets <NUM> or the outer skirt <NUM> attached thereto, and may even exert scissor-like shearing forces that may further damage the leaflets <NUM> or outer skirt <NUM>.

<FIG> shows a cross-sectional view of the radial displacement of adjacent struts 40f, <NUM>, <NUM>, 40i during compression of the valve, which may exert shearing forces that may damage the tissues of the leaflets <NUM> or the skirt <NUM>.

<FIG> shows an exemplary prosthetic heart valve wherein the outer skirt is not included. The leaflets in the embodiment of <FIG> are connected to the frame via an inner skirt. A disadvantage of this design is that leak channels may form between parallel outer struts 40a and the surrounding blood vessel wall the valve is expanded against, directing blood flow through such channels in the direction of arrows <NUM>, thereby resulting in an overall perivalvular leak flow in the direction of arrow <NUM>.

Novel frames disclosed herein can provide an improved strut geometry wherein some or all of the intermediate strut segments are bent to form recessed intermediate segments, configured to accommodate straight or also bent intermediate segments of overlapping struts.

<FIG> shows a schematic representation of a straight strut segment <NUM> overlaid over a bent strut <NUM> that has a recessed intermediate segment <NUM>, such that an intermediate segment <NUM> of the straight strut is received within and coupled to the recessed intermediate segment <NUM> at a junction JN. Though not shown in <FIG>, each end portion of the bent strut <NUM> can also include a recessed end portion.

According to some embodiments, recessed intermediate segments <NUM> or recessed end portions can be formed by providing a straight strut and punching it (e.g., plastically deforming it) at the regions of such desirable recesses. Advantageously, relatively straight struts are overlaid over struts having recessed intermediate segments such that at least one surface of the resulting frame is continuous or flush, such that the continuous surface does not include any substantial radial protrusion at the junctions JN (as well as at the apices).

As shown schematically in <FIG>, a strut <NUM> having recessed intermediate segments is coupled to struts <NUM>, such that while the junctions JN1 and JN2 bulge towards one side (lower side in this view, radially outer side of frame), the surface of the opposite side (upper side in this view, radially inner side of frame) remains substantially continuous adjacent to the leaflet <NUM>. According to some embodiments, a frame is formed by connecting a set or layer of parallel outer struts <NUM> having recessed intermediate segments <NUM>, with a set or layer of parallel crossing inner (straight) struts <NUM>, in the manner shown in <FIG>, such that the inner surface of the frame is substantially continuous adjacent to the leaflet <NUM>. Advantageously, the leaflets <NUM> can be connected via both of the edges to a continuous inner surface of the frame in such a geometry.

According to some embodiments, a frame is formed by connecting a set or layer of parallel inner struts <NUM> having recessed intermediate segments <NUM>, with a set or layer of parallel crossing outer (straight) struts <NUM>, such that the outer surface of the frame is substantially continuous. Advantageously, additional free inner volume may be achieved in the crimped frame of such a geometry, to accommodate inner soft components such as the leaflets and the inner skirt.

A further advantage of the disclosed embodiments is that they can enable adoption of a prosthetic heart valve that lacks an outer skirt, without the risk of leak channels forming along the outer surface of the frame. This may be accomplished at both proposed assemblages mentioned above, such that: (a) if the outer surface is continuous (i.e. junctions JN are bulging inwardly towards the lumen of the frame), no space will be formed between a frame fully expanded against the blood vessel's wall, thereby avoiding formation of leak channels, and (b) if the inner surface is continuous (i.e. junctions JN are bulging outwards the blood vessel's wall), the frame can be further expanded such that the junctions JN press against the blood vessel's wall (i.e. slightly penetrate the inner surface of the blood vessel), until the segments of the struts are tightly pressed against the blood vessel's wall, thereby avoiding formation of leak channels there between.

A further advantage of the disclosed technology is that the risk of shear forces acting on the leaflet or the skirt (see e.g., <FIG> and <FIG>) during compression or crimping is mitigated. As shown in <FIG>, as adjacent struts <NUM> and <NUM> are approaching each other along the same circumferential plane during frame compression, thereby avoiding shearing of the soft layers disposed there between while substantially avoiding the radial displacement between adjacent struts which may result in detrimental shear or "scissor"-like forces.

It should be understood that the disclosed embodiments can be adapted for delivering and implanting prosthetic devices in any of the native annuluses of the heart (e.g., the aortic, pulmonary, mitral, and tricuspid annuluses), and can be used with any of various delivery devices for delivering the prosthetic valve using any of various delivery approaches (e.g., retrograde, antegrade, transseptal, transventricular, transatrial, etc.).

For purposes of this description, certain aspects, advantages, and novel features of the embodiments of this disclosure are described herein. The disclosed methods, apparatus, and systems should not be construed as being limiting in any way. Instead, the present disclosure is directed toward all novel and nonobvious features and aspects of the various disclosed embodiments, alone and in various combinations and sub-combinations with one another. The methods, apparatus, and systems are not limited to any specific aspect or feature or combination thereof, nor do the disclosed embodiments require that any one or more specific advantages be present or problems be solved. The technologies from any example can be combined with the technologies described in any one or more of the other examples. In view of the many possible embodiments to which the principles of the disclosed technology may be applied, it should be recognized that the illustrated embodiments are only preferred examples and should not be taken as limiting the scope of the disclosed technology.

Although the operations of some of the disclosed embodiments are described in a particular, sequential order for convenient presentation, it should be understood that this manner of description encompasses rearrangement, unless a particular ordering is required by specific language set forth herein.

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 term "includes" means "comprises. " As used herein, "and/or" means "and" or "or", as well as "and" and "or". 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.

Directions and other relative references (e.g., inner, outer, upper, lower, etc.) 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 "inside," "outside,", "top," "down," "interior," "exterior," 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.

The valves and frames disclosed herein are described using an axial direction defined by the centerline of the annular frame and the overall bloodflow direction from an inflow end to an outflow end, a radial direction that is defined as radiating perpendicularly from the centerline of the frame, and a circumferential direction that is perpendicular to the axial and radial directions and extends around the centerline of the frame. The term "inner" refers to objects, surfaces and areas proximal to the centerline of the frame and the term "outer" refers objects, surfaces and areas that are farther from the centerline of the frame.

Claim 1:
A prosthetic heart valve comprising:
a radially expandable and compressible annular frame (<NUM>) comprising a plurality of struts (40a; 40b; 40c; 40d; 40f; <NUM>; <NUM>; 40i; <NUM>), the plurality of struts (40a; 40b; 40c; 40d; 40f; <NUM>; <NUM>; 40i; <NUM>) each including a plurality of segments disposed between two end portions of each strut and a respective intermediate segment (42a; 42b; <NUM>) disposed between respective two of the plurality of segments, the plurality of struts (40a; 40b; 40c; 40d; 40f; <NUM>; <NUM>; 40i; <NUM>) comprising inner struts (40b, 40c) and outer struts (40a) that are discrete from one another, wherein the outer struts (40a) overlap adjacent inner struts (40b, 40c) at pivot joints (J1; J2; J3), and radial expansion or compression of the annular frame causes the inner struts (40b, 40c) to pivot relative to the outer struts (40a) at the pivot joints (J1; J2; J3); and
a valvular structure mounted within the frame (<NUM>) that regulates blood flow through the prosthetic heart valve;
wherein the intermediate segments (42a; 42b; <NUM>) of at least some of the plurality of struts (40a; 40b; 40c; 40d; 40f; <NUM>; <NUM>; 40i; <NUM>) are bent to form recessed intermediate segments (42a; 42b; <NUM>) at the pivot joints (J1; J2; J3) to accommodate a respective straight or also bent intermediate segment of a respective overlapping strut belonging to others of the plurality of struts (40a; 40b; 40c; 40d; 40f; <NUM>; <NUM>; 40i; <NUM>), such that the others of the plurality of struts (40a; 40b; 40c; 40d; 40f; <NUM>; <NUM>; 40i; <NUM>) are seated in the recessed intermediate segments (42a; 42b; <NUM>) at the pivot joints (J1; J2; J3).