Systems, devices and methods for folded unibody heart valve stents
A replacement heart valve comprises a unibody, folded, double-wall stent, with a stent cover and a leaflet valve attached to the inner lumen of the stent. The heart valve is delivered using a multi-pulley, suture-based stent restraint assembly provided by fixed guide openings or structures along the distal end of the delivery system that independently permits expansion of the distal and proximal ends of the outer wall of the stent, and control of the inner wall expansion simultaneously with or separately from the expansion of the outer wall.
1. A replacement heart valve, comprising:
a unibody stent frame with a folded double-wall, the stent frame comprising:
a collapsed configuration and an expanded configuration;
an outer wall comprising a downstream open enlarged diameter region, a middle reduced diameter region, and an upstream closed enlarged diameter region;
a tubular inner wall with a central lumen;
a transition wall between the upstream closed enlarged diameter region of the outer wall and the inner wall; and
a first radius of curvature R 1 between the inner wall and the transition wall, a second radius of curvature R 2 between the transition wall and the outer wall, and a third radius of curvature R 3 at the middle reduced diameter region, wherein R 1 <R 2 <R 3 ; and
a replacement leaflet valve located in the central lumen of the inner wall;
wherein the unibody stent frame further comprises a plurality of longitudinal struts, wherein each longitudinal strut is contiguously located along the inner wall, transition wall and outer wall; and
wherein the plurality of longitudinal struts are integrally formed with a plurality of circumferential struts.
2. The valve of claim 1 , wherein the unibody stent frame further comprises a first curvature between the closed enlarged diameter region and the tubular inner wall.
3. The valve of claim 2 , wherein the unibody stent frame comprises a second curvature between the closed enlarged region and the open enlarged region.
4. The valve of claim 3 , wherein a radius of curvature at the first curvature is smaller than a radius of curvature at the second curvature.
5. The valve of claim 1 , wherein the outer wall surrounds at least 70 percent of the inner wall in the expanded configuration.
6. The valve of claim 5 , wherein the outer wall and transition wall completely surrounds the inner wall in the collapsed configuration.
7. The valve of claim 1 , wherein the tubular inner wall comprises a non-foreshortening region surrounding the replacement valve, when transitioning from the collapsed configuration to the expanded configuration.
8. The valve of claim 1 , wherein the inner wall is a non-foreshortening inner wall, and the outer wall is a foreshortening outer wall.
9. The valve of claim 1 , wherein for at least one of the plurality of longitudinal struts, contiguous segments of the longitudinal strut located in the inner wall, transition wall and outer wall are co-planar.
10. The valve of claim 9 , wherein the contiguous segments of the longitudinal strut are also co-planar with a central longitudinal axis of the unibody stent frame.
11. The valve of claim 1 , wherein at least three circumferential struts are located in the outer wall.
12. The valve of claim 1 , further comprising a stent covering, the stent covering comprising:
a first region on an outer surface of the outer wall;
a second region on an open end of the outer wall;
a third region on an outer surface of the transition wall;
a fourth region on an inner surface of the inner wall;
a fifth region on an open end of the inner wall;
a sixth region on an outer surface of the inner wall;
a seventh region on an inner surface of the outer wall; and
an eighth region portion between the inner surface of the outer wall and the outer surface of the inner wall.
13. The valve of claim 12 , wherein:
the first, second, third, and a portion of the fourth regions comprise a first fabric structure;
a portion of the fourth region and the fifth region comprises a second fabric structure; and
the sixth, seventh and eighth regions comprise a third fabric structure.
14. The valve of claim 13 , wherein the first fabric structure and the third fabric structure comprise a first fabric material and the second fabric structure comprises a second fabric material different from the first fabric material.
15. The valve of claim 14 , wherein the first fabric material is less permeable and thinner than the second fabric material.
16. The valve of claim 1 , wherein the stent frame further comprises a fourth radius of curvature R 4 at the downstream open enlarged diameter region of the outer wall.
17. The valve of claim 16 , wherein R 3 ≤R 4 .
18. The valve of claim 1 , wherein:
the stent frame further comprises a first bend angle A 1 between the inner wall and the transition wall, a second bend angle A 2 between the transition wall and the outer wall, and a third bend angle A 3 at the middle reduced diameter region; and
A 3 >A a .
19. The valve of claim 18 , wherein A 3 >A 2 .
20. The valve of claim 19 , wherein:
the stent frame further comprises a fourth bend angle R 4 at the downstream open enlarged diameter region of the outer wall; and
A 3 >A 4 .