Prosthetic valve and method of making a prosthetic valve
Prosthetic valves are provided with a leaflet assembly having at least one leaflet attached to a supporting element, which leaflet has a free margin that can move between a first position wherein the free margin is flexed away from a closure surface to allow body fluid to flow through the valve, and a second position wherein the free margin abuts the closure surface to close the valve, and wherein the leaflet, without pulsatile load on the valve, can form a coaptation height H of more than 0.1 mm along the length of the free margin. Such prosthetic valve provides good performance during prolonged time, and can be made using various materials for the leaflets.
1. A prosthetic heart valve that can take a first form wherein the valve is open and a second form wherein the valve is closed, the valve comprising:
a leaflet assembly having three leaflets attached to a supporting element at respective first and second commissures, the leaflets having a free margin that can move between a first position wherein the valve takes the first form and a second position wherein the valve takes the second form with each leaflet acting as a closure surface for the other leaflets, wherein
the leaflets can form a coaptation height in a longitudinal direction of the valve of between 1 and 15 mm along the free margin without a pulsatile load on the valve and without requiring substantial extension of the leaflets, wherein
the free margin of each leaflet has excess length relative to a minimum length needed to bridge a distance between the end of the leaflet's free margin at the first commissure to the end of the leaflet's free margin at the second commissure via the center of the valve, and wherein
the leaflets comprise an elastic sheet material having an elongation at break of 10% or less.
2. The prosthetic valve according to claim 1 , wherein the coaptation height is between 3 and 10 mm.
3. The prosthetic valve according to claim 1 , wherein the coaptation height is between 5 and 7 mm.
4. The prosthetic valve according to claim 1 , wherein the leaflets comprise an elastic sheet material having an elongation at break of less than 6%.
5. The prosthetic valve according to claim 1 , wherein elongation of the sheet material during use in the valve is less than 5%.
6. The prosthetic valve according to claim 1 , wherein the leaflets comprise a textile structure comprising at least one elastic yarn having an elongation at break of 10% or less.
7. The prosthetic valve according to claim 6 , wherein the textile structure is made by knitting, braiding or weaving the one or more elastic yarns.
8. The prosthetic valve according to claim 6 , wherein the textile structure is a woven fabric made from the elastic yarn.
9. The prosthetic valve according to claim 8 , wherein the woven fabric comprises plain, twill or basket weave patterns.
10. The prosthetic valve according to claim 8 , wherein the free margins of the leaflets are a selvedge of the woven fabric.
11. The prosthetic valve according to claim 6 , wherein the elastic yarn has a linear density of 5-120 dtex.
12. The prosthetic valve according to claim 6 , wherein the elastic yarn has a linear density of at least 7-30 dtex.
13. The prosthetic valve according to claim 6 , wherein the textile structure has a thickness of 20-200 μm.
14. The prosthetic valve according to claim 6 , wherein the textile structure has a thickness of 50-100 μm.
15. The prosthetic valve according to claim 6 , wherein the textile structure comprises ultrahigh molecular weight polyethylene (UHMWPE) filaments.
16. The prosthetic valve according to claim 6 , wherein the textile structure is a woven fabric with warp and yarns consisting essentially of ultrahigh molecular weight polyethylene (UHMWPE) filaments.
17. The prosthetic valve according to claim 1 , wherein the free margins have a length extending between first and second commissures, which length is at least 7% in excess relative to a theoretical length needed for closing the valve.
18. The prosthetic valve according to claim 1 , wherein each leaflet is attached to the supporting element along commissures that run in parallel with a longitudinal axis of the valve starting at the free margin, the commissures having a length of at least 1 mm.
19. The prosthetic valve according to claim 1 , further comprising a stent connected to the leaflet assembly.
20. A method of making the prosthetic valve according to claim 1 comprising:
(i) providing a sheet material,
(ii) forming a leaflet assembly comprising three leaflets and a supporting element from the sheet material, and
(iii) forming the valve therewith, wherein
forming the leaflet assembly according to step (ii) comprises shaping the leaflets to impose a geometry wherein the leaflets without pulsatile load on the valve and without requiring extension of the leaflets can form a coaptation height of between 1 and 15 mm along the free margin.
21. The method according to claim 20 , wherein step (iii) comprises connecting the leaflet assembly to a stent.