Stent for the positioning and anchoring of a valvular prosthesis in an implantation site in the heart of a patient
A stent for implantation at a native heart valve includes an expandable body having a first open end and second open end opposite the first open end. The sent includes a plurality of positioning arches positioned around an outer perimeter of the expandable body. Each positioning arch terminates in an apex facing toward the first open end of the expandable body. In an implanted position, the expandable body is oriented such that the first open end is upstream the second open end relative to a direction of blood flow through the native heart valve. In the implanted position, the apex of each of the positioning arches is configured to be positioned within a respective one of a plurality of pockets of the native heart valve and the first open end is positioned upstream of an annulus of the heart valve and out of contact with nerve bundles of the valve.
1. A stent for implantation at a native heart valve, the stent comprising:
an expandable body having a first open end and second open end opposite the first open end, a longitudinal axis of the expandable body extending between the first open end and the second open end; and
a plurality of positioning arches positioned around an outer perimeter of the expandable body, each positioning arch terminating in an apex facing in a direction toward the first open end of the expandable body,
wherein the stent has an implanted configuration when in an implanted position at the native heart valve, the implanted configuration comprising:
the expandable body being in an expanded configuration and oriented such that the first open end is upstream the second open end relative to a direction of blood flow through the native heart valve,
the apex of each of the positioning arches being positioned within a respective one of a plurality of pockets of the native heart valve, the pockets being defined by the native leaflets and a heart structure from which the native leaflets extend, and
the first open end of the expandable body extending past each of the apexes of the positioning arches by a distance such that the first open end of the expandable body is positioned upstream of an annulus of the heart valve and out of contact with nerve bundles of the heart valve.
2. The stent of claim 1 , wherein, in the implanted configuration of the stent, the distance the first open end of the expandable body extends past the apexes of the positioning arches is such that a distance between the first open end of the expandable body and the annulus of the heart valve is less than about 10 mm.
3. The stent of claim 1 , wherein, in the implanted configuration of the stent, the distance the first open end of the expandable body extends past the apexes of the positioning arches is such that a distance between the first open end and the annulus of the heart valve is less than about 6 mm.
4. The stent of claim 1 , wherein, in the implanted configuration of the stent, leaflets of the native heart valve are disposed between the positioning arches and another portion of the expandable body.
5. The stent of claim 1 , further comprising a plurality of retaining arches, the leaflets of the native heart valve being positioned between the plurality of positioning arches and the plurality of retaining arches in the implanted configuration of the stent.
6. The stent of claim 1 , wherein the native heart valve is an aortic valve and the native leaflets are aortic cusps, the positioning arches being configured to contact outflow surfaces of the aortic cusps in the implanted configuration of the stent.
7. The stent of claim 1 , wherein the first open end comprises an annular collar.
8. The stent of claim 7 , wherein the annular collar comprises at least one row of closed cells circumferentially disposed around the longitudinal axis of the expandable body.
9. The stent of claim 7 , wherein:
the annular collar has a height measured in an axial direction of the expandable body from the first open end of the expandable body, and
in a collapsed configuration of the expandable body, the apex of each positioning arch terminates at the annular collar.
10. The stent of claim 1 , wherein the expandable body comprises a plurality of retaining arches respectively associated with the positioning arches, wherein the retaining arches press radially outward against a vascular wall in the implanted configuration of the stent.
11. The stent of claim 10 , wherein the retaining arches comprise first ends collectively forming the first open end of the expandable body.
12. The stent of claim 1 , wherein the plurality of positioning arches are three positioning arches.
13. The stent of claim 1 , wherein the stent is configured to transition between a collapsed configuration in which the stent is configured for delivery to the native heart valve, and the implanted configuration.
14. The stent of claim 13 , wherein, when in the collapsed configuration, the expandable body has a diameter ranging from about 4 mm to about 8 mm.
15. The stent of claim 13 , wherein, when in the collapsed configuration, the expandable body has a length ranging from about 30 mm to about 42 mm.
16. The stent of claim 13 , wherein, when in the implanted configuration, the first open end has a diameter ranging from about 22 mm to about 33 mm.
17. An endoprosthesis comprising:
the stent of claim 1 ; and
a valvular prosthesis affixed to the stent.
18. A stent for implantation at a native heart valve, the stent comprising:
an expandable body having a first open end and a second open end opposite the first open end, a longitudinal axis of the expandable body extending between the first open end and the second open end; and
a plurality of positioning arches positioned around an outer perimeter of the expandable body, each positioning arch terminating in an apex facing in a direction toward the first open end of the expandable body,
wherein, in an implanted position of the stent at the native heart valve, the stent has an implanted configuration comprising:
the expandable body being in an expanded configuration and oriented such that the first open end is upstream the second open end relative to a direction of blood flow through the native heart valve, and
the first open end of the expandable body extending past each of the apexes of the positioning arches by a distance such that the first open end of the expandable body is positioned upstream of an annulus of the native heart valve by a distance of less than about 10 mm.
19. The stent of claim 18 , wherein, in the implanted configuration of the stent, the distance the first open end of the expandable body extends past the apexes of the positioning arches is such that the first open end is positioned upstream of the annulus of the native heart valve by a distance of less than about 6 mm.
20. The stent of claim 18 , wherein the expandable body comprises at least one row of closed cells circumferentially disposed around the longitudinal axis of the expandable body at the first open end.
21. The stent of claim 20 , wherein, in the implanted configuration of the stent, the at least one row of closed cells is configured to press radially outward against a vascular wall.
22. The stent of claim 20 , wherein the at least one row of closed cells comprises a plurality of rows of closed cells, the plurality of rows of closed cells forming an annular collar at the first open end.
23. The stent of claim 20 , wherein the stent is configured to transition between a collapsed configuration in which the stent is configured for delivery to the native heart valve, and the implanted configuration.
24. The stent of claim 23 , wherein, in a collapsed configuration of the stent, the apex of each positioning arch terminates at an annular collar.