Rolled minimally-invasive heart valves and methods of manufacture

• US 20030055495A1
• Filed: 11/01/2002
• Published: 03/20/2003
• Est. Priority Date: 03/23/2001
• Status: Active Grant

• Current Assignee: Brandon G. Walsh, David Forster, Gregory Martin Mast, Jibin Yang, John C. Muskivitch, Matthew L. Pease, Travis Rowe, Tyson Gustus
• Original Assignee: Brandon G. Walsh, David Forster, Gregory Martin Mast, Jibin Yang, John C. Muskivitch, Matthew L. Pease, Travis Rowe, Tyson Gustus
• Inventors: Mast, Gregory Martin, Gustus, Tyson, Walsh, Brandon G., Rowe, Travis, Muskivitch, John C., Pease, Matthew L., Yang, Jibin, Forster, David
• Granted Patent: US 7,374,571 B2
• Time in Patent Office: Days
• US Class Current: 623/2.11
• CPC Class Codes: A61F 2/2418 Scaffolds therefor, e.g. support stents
• CPC Class Codes: A61F 2/848 having means for fixation to the vessel wall, e.g. barbs
• CPC Class Codes: A61F 2/92 Stents in the form of a rolled-up sheet expanding after insertion into the vessel , e.g. with a spiral shape in cross-section
• CPC Class Codes: A61F 2220/0016 with sharp anchoring protrusions, e.g. barbs, pins, spikes
• CPC Class Codes: A61F 2220/0075 sutured, ligatured or stitched, retained or tied with a rope, string, thread, wire or cable

Abstract

Expandable heart valves for minimally invasive valve replacement surgeries are disclosed. The valves are rolled into a first, contracted configuration for minimally invasive delivery using a catheter, and then unrolled or unfurled at the implantation site. One- and two-piece stents may be used in conjunction with a plurality of flexible leaflet-forming membranes. The stents may include an annulus section, a sinus section with the membranes attached over sinus apertures, and an outflow section. Lockout tabs and making slots secure the stents in their expanded shapes. Alignment structure ensures concentric unfurling of the stent. Anchoring elements at the stent edges or in the stent body secure the valve within the annulus. A method of manufacture includes shape setting the sheet-like stent to ensure an outward bias during deployment. The stent may also include dear tracks for engagement with a gear mechanism for deployment. The stent is desirably made of a superelastic material such as Nitinol and may have areas removed or thinned to reduce the bending stresses when rolled into its small spiral for catheter delivery.

Claims

1. A rolled prosthetic heart valve suitable for minimally invasive delivery and implantation in a heart valve annulus, comprising:

a stent body that has a generally tubular shape set and is structured to be rolled into a spiral sized to pass through a patient'"'"'s vasculature; and

a plurality of flexible membranes fastened to the inside of the stent body to form occluding leaflets of the heart valve.

2. The heart valve of claim 1, wherein the stent body is adapted to conform to a first, contracted configuration in which the stent body is spirally rolled about an axis, and a second, expanded configuration in which the stent body is substantially unrolled and at least partly forms a tube centered about the axis and sized to engage an annulus of a patient'"'"'s heart valve.

3. The heart valve of claim 2, further including at least one guide to insure the stent body expands evenly along the axis during a conversion between the first, contracted configuration to the second, expanded configuration.

4. The heart valve of claim 3, wherein the stent body defines a pair of opposed side edges that generally mate in the second, expanded configuration, and a pair of opposed end edges that extend between the side edges, and the at least one guide comprises a tab extending generally radially along each one of the end edges.

5. The heart valve of claim 1, wherein the stent body forms the only rolled structure in the heart valve.

6. The heart valve of claim 1, wherein the stent body has an annulus section on an inflow end, a sinus section, and an outflow section, the sinus section being between the annulus section and outflow section and having a plurality of sinus apertures outward of each membrane.

7. The heart valve of claim 6, wherein there are three generally semi-circular sinus apertures, and three separate membranes fastened around the edge of each except on one side which forms a free edge of each leaflet.

8. The heart valve of claim 7, wherein the outer edge of each membrane is folded over and fastened to an inner surface of the stent body adjacent an edge of the associated sinus aperture.

9. The heart valve of claim 1, wherein the stent body is adapted to conform to a first, contracted configuration in which the stent body is spirally rolled about an axis, and a second, expanded configuration in which the stent body is substantially unrolled and at least partly forms a tube centered about the axis and sized to engage an annulus of a patient'"'"'s heart valve, the tube having a pair of end edges, and wherein the stent body has a pair of opposed side edges that mate in the second, expanded configuration, the stent body further including lockout structure to retain the opposed side edges in mating engagement.

10. The heart valve of claim 9, wherein the lockout structure comprises tabs formed on both of the end edges and adjacent one of the side edges, and slots formed in both of the end edges adjacent the other of the side edges that are sized to receive and retain the tabs.

11. The heart valve of claim 9, wherein the lockout structure both prevents further expansion of the stent body and contraction from the expanded tubular shape.

12. The heart valve of claim 1, further including at least one anchoring element comprising a curved strip extending radially outward from the stent body designed to prevent axial migration of the heart valve after implantation in the annulus.

13. The heart valve of claim 1, wherein the flexible membranes are bioprosthetic tissue.

14. The heart valve of claim 13, wherein the bioprosthetic tissue is compressed to reduce its thickness.

15. The heart valve of claim 1, wherein the stent body is made of a superelastic material.

16. A prosthetic heart valve suitable for minimally invasive delivery and expansion against a heart valve annulus, comprising:

a stent body that has a first, contracted configuration with a first diameter for delivery through the vasculature of a patient and a second, expanded configuration with a predetermined maximum second diameter regardless of the size of the heart valve annulus.

17. The heart valve of claim 16, wherein the stent body is a sheet-like member having a generally tubular shape and adapted to be rolled into a spiral sized to pass through a patient'"'"'s vasculature.

18. The heart valve of claim 17, wherein the stent body has a plurality of sinus apertures and the heart valve further includes a plurality of flexible membranes fastened around the sinus apertures to form occluding leaflets of the heart valve.

19. The heart valve of claim 17, wherein the stent body is adapted to conform to a first, contracted configuration in which the stent body is spirally rolled about an axis, and a second, expanded configuration in which the stent body is substantially unrolled and at least partly forms a tube centered about the axis and sized to engage an annulus of a patient'"'"'s heart valve, the tube having a pair of end edges, wherein the stent body has a pair of opposed side edges that mate in the second, expanded configuration, the stent body further including lockout structure to retain the opposed side edges in mating engagement and define the predetermined maximum second diameter.

20. The heart valve of claim 19, wherein the lockout structure comprises tabs formed on both of the end edges and adjacent one of the side edges, and slots formed in both of the end edges adjacent the other of the side edges that are sized to receive and retain the tabs.

21. The heart valve of claim 19, wherein the lockout structure both defines the predetermined maximum second diameter thus preventing further expansion of the stent body, and prevents contraction from the expanded tubular shape.

22. The heart valve of claim 16, further including at least one anchoring element comprising a curved strip extending radially outward from the stent body designed to prevent axial migration of the heart valve after implantation in the annulus.

23. A method of prosthetic heart valve implantation, comprising:

positioning a rolled prosthetic heart valve at a heart valve annulus; and

unfurling the prosthetic heart valve from a spirally-wound contracted, first configuration to an unwound expanded, second configuration at the annulus.

24. The method of claim 23, wherein the prosthetic heart valve comprises a single stent body having a plurality of flexible, biocompatible membranes incorporated therein that form heart valve leaflets in the expanded configuration.

25. The method of claim 23, further including anchoring the prosthetic heart valve in its expanded configuration to the heart valve annulus.

26. The method of claim 23, wherein the native heart valve leaflets of the heart valve annulus are left in place and the step of unfurling causes the prosthetic heart valve to contact and outwardly compress the native leaflets.

27. The method of claim 23, wherein the step of unfurling further includes ensuring that the prosthetic heart valve remains generally tubular.

28. The method of claim 23, further including the step of locking the prosthetic heart valve in its expanded configuration.

29. A rolled prosthetic heart valve suitable for minimally invasive delivery and implantation in a heart valve annulus, comprising:

a stent body that has a generally tubular shape set and is structured to be rolled about a first axis into a contracted spiral sized to pass through a patient'"'"'s vasculature and substantially unrolled into an expanded tube centered about a second axis parallel to the first axis, the tube being sized to engage an annulus of a patient'"'"'s heart valve and having a pair of opposed side edges and a pair of generally axially-oriented and mating end edges;

lockout structure to retain the opposed side edges in mating engagement; and

valve leaflets connected to the stent body.

30. The heart valve of claim 29, wherein the valve leaflets comprise a plurality of flexible membranes fastened to the inside of the stent body to form occluding leaflets of the heart valve.

31. The heart valve of claim 30, wherein the stent body has an annulus section on an inflow end, a sinus section, and an outflow section, the sinus section being between the annulus section and outflow section and having a sinus aperture outward of each membrane.

32. The heart valve of claim 31, wherein there are three generally semi-circular sinus apertures, and three separate membranes fastened around the edge of each except on one side which forms a free edge of each leaflet.

33. The heart valve of claim 32, wherein the outer edge of each membrane is folded over and fastened to an inner surface of the stent body adjacent an edge of the associated sinus aperture.

34. The heart valve of claim 29, further including at least one guide to insure the stent body expands evenly along the axis during a conversion between the contracted spiral to the expanded tube and the first axis remains parallel to the second axis.

35. The heart valve of claim 34, wherein the at least one guide comprises a tab extending generally radially from each one of the end edges.

36. The heart valve of claim 29, wherein the lockout structure comprises tabs formed on both of the end edges and adjacent one of the side edges, and slots formed in both of the end edges adjacent the other of the side edges that are sized to receive and retain the tabs.

37. The heart valve of claim 29, wherein the lockout structure both prevents further expansion of the stent body and contraction from the expanded tubular shape.

38. The heart valve of claim 29, wherein the lockout structure ensures the stent body has an expanded tubular shape with a predetermined maximum diameter regardless of the size of the heart valve annulus.

39. The heart valve of claim 29, further including at least one anchoring element comprising a curved strip extending radially outward from the stent body designed to prevent axial migration of the heart valve after implantation in the annulus.

40. The heart valve of claim 29, wherein the flexible membranes are bioprosthetic tissue.

41. The heart valve of claim 40, wherein the bioprosthetic tissue is compressed to reduce its thickness.

42. The heart valve of claim 29, wherein the stent body is a sheet-like member having reduced thickness tabs on a first side edge that form the inner portion of the contracted spiral.

43. A rolled prosthetic heart valve suitable for minimally invasive delivery and implantation in a heart valve annulus, comprising:

a sheet-like stent body that has a generally tubular shape set and is structured to be rolled about a first axis into a contracted spiral sized to pass through a patient'"'"'s vasculature and substantially unrolled into an expanded tube centered about a second axis parallel to the first axis, the tube being sized to engage an annulus of a patient'"'"'s heart valve and having a pair of opposed side edges and a pair of generally axially-oriented and mating end edges;

at least one anchoring element comprising a curved strip extending radially outward from the stent body designed to prevent axial migration of the heart valve after implantation in the annulus; and

valve leaflets connected to the stent body.

44. The heart valve of claim 43, wherein-the valve leaflets comprise a plurality of flexible membranes fastened to the inside of the stent body to form occluding leaflets of the heart valve.

45. The heart valve of claim 44, wherein the stent body has an annulus section on an inflow end, a sinus section, and an outflow section, the sinus section being between the annulus section and outflow section and having a sinus aperture outward of each membrane.

46. The heart valve of claim 43, wherein there are at least three anchoring elements each formed by a pair of parallel slits in the stent that are bent radially outward in an arcuate shape so as to form partial rings or loops.

47. The heart valve of claim 43, wherein the stent body has an annulus section on an inflow end, a sinus section, and an outflow section, the sinus section being between the annulus section and outflow section, and wherein there are at least three anchoring elements on both the annulus section and the outflow section.

48. The heart valve of claim 43, further including at least one guide to insure the stent body expands evenly along the axis during a conversion between the contracted spiral to the expanded tube and the first axis remains parallel to the second axis.

49. The heart valve of claim 48, wherein the at least one guide comprises a tab extending generally radially from each one of the end edges.

50. The heart valve of claim 43, further including lockout structure to retain the opposed side edges in mating engagement.

51. The heart valve of claim 50, wherein the lockout structure comprises tabs formed on both of the end edges and adjacent one of the side edges, and slots formed in both of the end edges adjacent the other of the side edges that are sized to receive and retain the tabs.

52. The heart valve of claim 50, wherein the lockout structure both prevents further expansion of the stent body and contraction from the expanded tubular shape.

53. The heart valve of claim 50, wherein the lockout structure ensures the stent body has an expanded tubular shape with a predetermined maximum diameter regardless of the size of the heart valve annulus.

54. The heart valve of claim 43, wherein the flexible membranes are bioprosthetic tissue.

55. The heart valve of claim 54, wherein the bioprosthetic tissue is compressed to reduce its thickness.

56. The heart valve of claim 43, wherein the stent body has reduced thickness tabs on a first side edge that form the inner portion of the contracted spiral.

57. A rolled prosthetic heart valve suitable for minimally invasive delivery and implantation in a heart valve annulus, comprising:

a sheet-like stent body that has a generally tubular shape set and is structured to be rolled about a first axis into a contracted spiral sized to pass through a patient'"'"'s vasculature and substantially unrolled into an expanded tube centered about a second axis parallel to the first axis, the tube being sized to engage an annulus of a patient'"'"'s heart valve and having a pair of opposed side edges and a pair of generally axially-oriented and mating end edges, wherein the stent body has reduced thickness tabs on a first side edge that form the inner portion of the contracted spiral; and

valve leaflets connected to the stent body.

58. The heart valve of claim 57, wherein the valve leaflets comprise a plurality of flexible membranes fastened to the inside of the stent body to form occluding leaflets of the heart valve.

59. The heart valve of claim 58, wherein the stent body has an annulus section on an inflow end, a sinus section, and an outflow section, the sinus section being between the annulus section and outflow section and having a sinus aperture outward of each membrane.

60. The heart valve of claim 57, further including at least one guide to insure the stent body expands evenly along the axis during a conversion between the contracted spiral to the expanded tube and the first axis remains parallel to the second axis.

61. The heart valve of claim 57, further including lockout structure to retain the opposed side edges in mating engagement.

62. The heart valve of claim 61, wherein the lockout structure both prevents further expansion of the stent body and contraction from the expanded tubular shape.

63. The heart valve of claim 57, wherein the sheet-like stent body further includes thinned bend relief regions in areas having the most material.

64. The heart valve of claim 63, wherein the thinned regions are between 25%-50% of the thickness of the rest of the sheet-like stent body.

65. The heart valve of claim 64, wherein the thinned regions are between 40%-50% of the thickness of the rest of the sheet-like stent body.