Tissue heart valves

• US 5,928,281 A
• Filed: 03/27/1997
• Issued: 07/27/1999
• Est. Priority Date: 03/27/1997
• Status: Expired due to Term

• Current Assignee: Edwards Lifesciences Corporation
• Original Assignee: Baxter International Inc.
• Inventors: Nguyen, Than, Lam, Hung Ly, Huynh, Van Le, Kafesjian, Ralph, Guo, Xiaoming G.
• Primary Examiner(s): Willse, David H.
• Application Number:
  US08/826,408
• Time in Patent Office: 852 Days
• Field of Search: 623/2, 623/900
• US Class Current: 623/2.14
• CPC Class Codes: A61F 2/2409 Support rings therefor, e.g. for connecting valves to tissue annuloplasty rings A61F2/2442
• CPC Class Codes: A61F 2/2412 with soft flexible valve members, e.g. tissue valves shaped like natural valves check valves with flexible valve members in general F16K15/14
• CPC Class Codes: A61F 2/2415 Manufacturing methods
• CPC Class Codes: A61F 2220/0075 sutured, ligatured or stitched, retained or tied with a rope, string, thread, wire or cable
• CPC Class Codes: Y10S 623/90 Stent for heart valve
• CPC Class Codes: Y10S 623/91 Heart

Abstract

Improved, adaptable tissue-type heart valves and methods for their manufacture are disclosed wherein a dimensionally stable, pre-aligned tissue leaflet subassembly is formed and its peripheral edge clamped between and attached to an upper shaped wireform and a lower support stent. A variety of adaptable structural interfaces including suture rings, flanges, and conduits may be attached to the support stent with or without an outlet conduit disposed about the wireform to provide a tissue-type heart valve adaptable for use in either a natural heart or in mechanical pumping devices.

Claims

1. A tissue-type heart valve comprising:

a dimensionally stable, pre-aligned and pre-assembled tissue leaflet subassembly including a plurality of leaflets, wherein each leaflet includes a cusp edge opposite from a coapting edge and two leaflet tabs extending from the junctions between the cusp and coapting edges in generally opposite directions, the pre-alignment of the leaflets in the subassembly creating a plurality of pairs of mating leaflet tabs extending outward from the subassembly, one pair of mating leaflet tabs per adjacent pair of leaflets;

a generally circular wireform having a bottom surface dimensioned to receive said pre-aligned tissue leaflet subassembly in fixed, mating engagement said wireform having lower cusps interrupted by upwardly extending commissures, the cusp edges of the leaflets in the pre-assembled tissue leaflet subassembly being attached along the cusps of the wireform to form a leaflet/wireform subassembly; and

a generally circular support stent having an upper surface dimensioned to seat and fix in mating engagement with said leaflet/wireform subassembly, the support stent having upwardly extending flexible commissure posts to which the pairs of mating leaflet tabs attach.

2. The tissue-type heart valve of claim 1 wherein said wireform is provided with a cloth cover.

3. The tissue-type heart valve of claim 1 wherein said support stent upper surface is provided with a deformable, leaflet engaging seat.

4. The tissue-type heart valve of claim 1 wherein said support stent is provided with a cloth cover.

5. The tissue-type heart valve of claim 1 further comprising an adaptable structural interface fixedly disposed upon said support stent.

6. The tissue-type heart valve of claim 5 wherein said adaptable structural interface comprises a suture ring.

7. The tissue-type heart valve of claim 5 wherein said adaptable structural interface comprises a flange.

8. The tissue-type heart valve of claim 5 wherein said adaptable structural interface comprises a conduit.

9. The tissue-type heart valve of claim 1 further comprising an outlet conduit fixedly disposed about said wireform.

10. The tissue-type heart valve of claim 9 further comprising an inlet conduit fixedly disposed upon said support stent.

11. The valve of claim 1, wherein each commissure of the wireform defines a generally axial space between two sections of wire through which one of the pairs of outwardly extending leaflet tabs extend, the flexible stent commissures extending radially outside of the wireform commissures, and wherein each pair of mating leaflet tabs is separated within the axial space and the separated tabs pass on opposite sides of the associated stent commissure and attach thereto so as to be clamped between the stent commissure and wireform commissure upon a radially inward force being applied to the leaflets.

12. The valve of claim 11, wherein the leaflet ends extend around the outside of the stent commissure and are rejoined at a stitched butt joint.

16. The tissue-type heart valve of claim 11 wherein said support stent is provided with a cloth cover.

13. A tissue-type heart valve comprising:

a dimensionally stable, pre-aligned tissue leaflet subassembly formed of a plurality of substantially identical tissue coapting leaflets, each of said leaflets having a generally linear coapting mating edge having opposing ends and a generally arcuate peripheral cusp extending therebetween, said opposing ends of adjacent leaflets having been templated and attached to one another to define a plurality of pairs of aligned, mating, leaflet ends;

a generally circular, cloth-covered wireform having top and bottom surfaces and a generally sinusoidal periphery defining a plurality of axially projecting commissures, each of said commissures corresponding to one of said pairs of aligned, mating, leaflet ends, said wireform bottom surface dimensioned to receive and fixedly dispose in mating engagement with said pre-aligned tissue leaflet subassembly; and

a generally circular support stent having an upper surface dimensioned to seat and fix in mating engagement with said tissue leaflet subassembly fixedly disposed in mating engagement with said bottom surface of said wireform, the support stent including a generally stiff lower ring portion and a plurality of flexible commissure posts axially projecting up from the ring portion approximately the same height as the commissures of the wireform.

14. The tissue-type heart valve of claim 13 wherein each of said tissue leaflet peripheral cusps is sewn to said cloth-covered wireform from commissure to commissure.

15. The tissue-type heart valve of claim 13 wherein said support stent upper surface is provided with a leaflet cusp engaging seat.

17. The tissue-type heart valve of claim 13 wherein said support stent includes a two-part structure with a flexible inner member including the axially projecting commissures, and a stiff outer member defining the stiff lower ring portion.

18. The tissue-type heart valve of claim 17 wherein the flexible inner member has an upper surface defining cusps and the axially projecting commissures, and the stiff outer member has an upper surface defining cusps juxtaposed with the inner member cusps, the combined upper surfaces of the inner and outer members defining the support stent upper surface.

19. The tissue-type heart valve of claim 13 further comprising an adaptable structural interface fixedly disposed upon said support stent.

20. The tissue-type heart valve of claim 19 wherein said adaptable structural interface comprises a suture ring.

21. The tissue-type heart valve of claim 19 wherein said adaptable structural interface comprises a flange.

22. The tissue-type heart valve of claim 19 wherein said adaptable structural interface comprises a conduit.

23. The tissue-type heart valve of claim 13 further comprising an outlet conduit fixedly disposed about said wireform.

24. The tissue-type heart valve of claim 23 further comprising an inlet conduit fixedly disposed upon said support stent.

25. The valve of claim 13, wherein each commissure of the wireform defines a generally axial space between two sections of wire through which one of the pairs of mating leaflet ends extend and attaches to one of the stent commissures.

26. The valve of claim 25, wherein the flexible stent commissures are disposed adjacent and radially outside of the wireform commissures, and wherein each pair of mating leaflet ends is separated within the axial space and the separated ends pass on opposite sides of the associated stent commissure and attach to one another so as to be clamped between the stent commissure and wireform commissure upon a radially inward force being applied to the leaflets.

27. The valve of claim 26, wherein the separated leaflet ends extend around the outside of the stent commissure and are attached together at a stitched butt joint.

28. A tissue-type heart valve comprising:

an annular wireform having a plurality of axially projecting commissures terminating in arcuate tips, the commissures being separated by arcuate cusps having a substantially larger radius of curvature than the tips, the commissures and tips being formed in a sinusoidal configuration with the commissures extending in the opposite axial direction from the cusps so that each commissure is defined by spaced apart portions of the wireform in adjacent cusps joined by one of the tips;

a tissue leaflet subassembly attached within the annular wireform and formed by a plurality of substantially identical tissue leaflets, each of the leaflets having a coapting mating edge having opposing ends and a generally arcuate peripheral cusp extending therebetween coupled to one of the wireform cusps, the opposing ends of adjacent leaflets being attached to one another to define a plurality of pairs of mating leaflet ends each of which is associated with and extends between the spaced apart wireform portions of one of the commissures; and

a generally cylindrical support stent having on one edge a plurality of alternating cusps and commissures adapted to matingly engage with the attached annular wireform and tissue leaflet subassembly, each stent commissure being associated with and extending substantially the same axial distance as one of the wireform commissures, wherein each pair of mating leaflet ends is separated by and attached around opposite sides of the associated stent commissure.

29. The valve of claim 28, wherein the wireform is cloth-covered with the tissue leaflet subassembly connected to the cloth with sutures.

30. The valve of claim 29, wherein the tissue leaflets are stitched along their cusps to the cusps of the wireform cloth.

31. The valve of claim 28, wherein each pair of separated leaflet ends is jointly attached to the wireform and stent commissures with stitching.

32. The valve of claim 31, wherein the leaflet ends are trimmed flush with the outside of the stent commissure.

33. The valve of claim 31, wherein the leaflet ends extend around the outside of the stent commissure and are rejoined at a stitched butt joint.

34. The valve of claim 28, further comprising a flange fixedly disposed upon said support stent.

35. The valve of claim 28, further comprising a conduit fixedly disposed upon said support stent.

36. The valve of claim 28, further comprising an outlet conduit fixedly disposed about said wireform.

37. The valve of claim 36, further comprising an inlet conduit fixedly disposed upon said support stent.

38. A tissue-type heart valve comprising:

an annular wireform having a plurality of axially projecting commissures terminating in arcuate tips, the commissures being separated by arcuate cusps having a substantially larger radius of curvature than the tips, the commissures and tips being formed in a sinusoidal configuration with the commissures extending in the opposite axial direction from the cusps so that each commissure is defined by spaced apart portions of the wireform in adjacent cusps joined by one of the tips;

a tissue leaflet subassembly attached within the annular wireform and formed by a plurality of substantially identical tissue leaflets, each of the leaflets having a coapting mating edge having opposing ends and a generally arcuate peripheral cusp extending therebetween coupled to one of the wireform cusps, the opposing ends of adjacent leaflets being attached to one another to define a plurality of pairs of mating leaflet ends each of which is associated with and extends between the spaced apart wireform portions of one of the commissures; and

a generally cylindrical support stent having on one edge a plurality of alternating cusps and commissures adapted to matingly engage with the attached annular wireform and tissue leaflet subassembly, each stent commissure being associated with and extending substantially the same axial distance as one of the wireform commissures, wherein each pair of mating leaflet ends is separated and attached around opposite sides of the associated stent commissure, wherein the stent further includes inner and outer support members, with the inner support member exhibiting the cusps and commissures, and the outer support member conforming to the cusps but being truncated in the region of the inner support member commissures so as to provide stiffness to the combined support members except at the inner support member commissures.

39. The valve of claim 38, wherein the stent is cloth-covered.

40. The valve of claim 39, wherein the cloth covering the stent is folded to form a cloth sewing edge extending along the alternating stent cusps and commissures to facilitate attachment to the wireform and tissue leaflet subassembly.

41. The valve of claim 39, wherein the stent commissures include sewing holes and the cloth covering is secured to the stent commissures with sutures through the sewing holes.

42. A tissue-type heart valve comprising:

an annular wireform having a plurality of axially projecting commissures terminating in arcuate tips, the commissures being separated by arcuate cusps having a substantially larger radius of curvature than the tips, the commissures and tips being formed in a sinusoidal configuration with the commissures extending in the opposite axial direction from the cusps so that each commissure is defined by spaced apart portions of the wireform in adjacent cusps joined by one of the tips;

a tissue leaflet subassembly attached within the annular wireform and formed by a plurality of substantially identical tissue leaflets, each of the leaflets having a coapting mating edge having opposing ends and a generally arcuate peripheral cusp extending therebetween coupled to one of the wireform cusps, the opposing ends of adjacent leaflets being attached to one another to define a plurality of pairs of mating leaflet ends each of which is associated with and extends between the spaced apart wireform portions of one of the commissures;

a generally cylindrical support stent having on one edge a plurality of alternating cusps and commissures adapted to matingly engage with the attached annular wireform and tissue leaflet subassembly; and

a suture ring fixedly disposed upon a lower end of said valve comprising a suturable annulus having upwardly opening depressions on an internal circumference corresponding in number to the number of cusps of the wireform, wherein the suture ring has a bore sized to receive the stent with the wireform cusps being positioned in the depressions.

43. The valve of claim 42, wherein the suture ring comprises a sponge waffle covered with cloth.

44. The valve of claim 43, wherein the sponge waffle comprises an upwardly facing outer ledge and an inner lip projecting up from the ledge in which said depressions are formed.

45. The valve of claim 44, further comprising a ring washer sized to closely surround the lip and rest on the ledge.

46. The valve of claim 45, further comprising a single cloth covering surrounding the sponge waffle, and folded around the external surfaces of the ring washer and tucked between the ring washer and the sponge waffle.

47. The valve of claim 42, wherein each stent commissure is associated with and extends substantially the same axial distance as one of the wireform commissures, and wherein each pair of mating leaflet ends is separated and attached around opposite sides of the associated stent commissure.