Prosthetic heart valves with flexible leaflets
A prosthetic heart valve of the type that includes a hollow annular stent and a plurality of flexible leaflets that are attached to the stent. One or more fixture structures are used to attach the leaflets to the stent so that sutures do not have to be used for that purpose. The fixture structures preferably extend annularly at least substantially all the way around the valve. Surfaces of the fixture structures that can come into contact with portions of the leaflets that move during use of the valve can be shaped to help beneficially shape those leaflet portions during their movements.
1. A prosthetic heart valve, comprising:
a hollow, annular, stent structure having a blood-inflow edge and a blood-outflow edge, the blood-outflow edge defining portion that includes a plurality of commissure regions spaced from one another a plurality of intermediate edge portions interposed between the commissure regions, each intermediate edge portion having a midpoint between adjacent commissure regions, the blood-outflow edge having a luminal side and an abluminal side, the blood-outflow edge in the commissure regions being spaced from the blood-inflow edge by first distances, and the blood-outflow edge in the intermediate edge portions being spaced from the blood-inflow edge by a second distance less than the first distances;
a plurality of leaflets, each leaflet having a portion positioned over the intermediate edge portion between respective pairs of annularly adjacent ones of the commissure regions, the portion of at least one of the leaflets and the intermediate edge portion between at least one of the respective pairs of commissure regions collectively defining a receiving structure; and
a clip structure having first and second legs spaced apart so as to define a channel therebetween, the clip structure being connected to the receiving structure in an assembled position with the first leg on the luminal side of the blood-outflow edge and the second leg on the abluminal side of the blood-outflow edge, wherein the clip structure in the assembled position extends along and beyond the midpoint of the intermediate edge portion extending between the at least one of the respective pairs of commissure regions.
2. The prosthetic heart valve defined in claim 1 , wherein the stent structure and the clip structure include interengaging shapes for securing the clip structure to the receiving structure in the assembled position.
3. The prosthetic heart valve defined in claim 2 , wherein material of the at least one leaflet is interposed between the interengaging shapes in the assembled position.
4. The prosthetic heart valve defined in claim 2 , wherein the interengaging shapes are shaped to facilitate placement of the clip structure on the receiving structure but to thereafter resist removal of the clip structure from the receiving structure.
5. The prosthetic heart valve defined in claim 4 , wherein the clip structure is configured to elastically deform during placement of the clip structure on the receiving structure and to thereafter resiliently apply clamping pressure to the at least one leaflet against the stent structure.
6. The prosthetic heart valve defined in claim 1 , wherein the clip structure includes a clip surface that can be contacted by a portion of the at least one leaflet that moves during use of the prosthetic heart valve.
7. The prosthetic heart valve defined in claim 6 , wherein the clip surface is shaped to increase the radius of curvature of flexure of the portion of the at least one leaflet that contacts the clip surface during use of the prosthetic heart valve.
8. The prosthetic heart valve defined in claim 1 , wherein the stent structure has a lumen extending in a blood flow direction and the receiving structure has a thickness in directions radial to the blood flow direction, and
the channel in the clip structure has an open end opposite a closed end, the open end having an initial width between the first and second legs when the clip structure is apart from the receiving structure, the initial width being less than the thickness of the receiving structure.
9. The prosthetic heart valve defined in claim 8 , wherein the first and second legs of the clip structure are biased toward the initial width, and are movable away from one another to a dimension greater than the initial width for connection of the clip structure in the assembled position to the receiving structure.
10. The prosthetic heart valve defined in claim 9 , wherein one of the first and second legs of the clip structure includes a cam surface for engaging the receiving structure and moving the one of the first and second legs away from the other of the first and second legs during connection of the clip structure in the assembled position to the receiving structure.
11. The prosthetic heart valve defined in claim 8 , wherein
the stent structure has a retaining surface on at least one of the luminal side or the abluminal side, the retaining surface extending in a direction orthogonal to the blood flow direction, and
the clip structure has an engagement surface on at least one of the first and second legs, the engagement surface extending in the direction orthogonal to the blood flow direction in the assembled position, the engagement surface of the clip structure engaging the retaining surface of the stent structure in the assembled position to resist removal of the clip structure from the receiving structure.
12. The prosthetic heart valve defined in claim 1 , wherein the portion of the at least one leaflet is positioned over the intermediate edge portion substantially continuously between the at least one of the respective pairs of commissure regions.
13. The prosthetic heart valve defined in claim 1 , wherein the clip structure in the assembled position extends substantially continuously between at least one of the respective pairs of commissure regions.