HEART VALVE PROSTHESIS WITH OPEN STENT

• US 20150112421A1
• Filed: 12/21/2012
• Published: 04/23/2015
• Est. Priority Date: 12/23/2011
• Status: Active Grant

• Current Assignee: Abiomed, Inc. (Johnson & Johnson)
• Original Assignee: Abiomed, Inc. (Johnson & Johnson)
• Inventors: Barnes, Terrance Gerard, Corbett, Scott
• Granted Patent: US 9,456,898 B2
• Time in Patent Office: Days
• US Class Current: 623/1.16
• CPC Class Codes: A61F 2/2403 with pivoting rigid closure members check valves with hinged closure members in general F16K15/03
• 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 2/2418 Scaffolds therefor, e.g. support stents
• CPC Class Codes: A61F 2/2427 Devices for manipulating or deploying heart valves during implantation
• CPC Class Codes: A61F 2/89 the wire-like elements comprising two or more adjacent rings flexibly connected by separate members

Abstract

A prosthetic apparatus is disclosed including: a tubular stent disposed about a longitudinal axis and extending from a proximal end to a distal end, the stent defining a tubular passage between the ends. The tubular stent has a proximal portion, a distal portion, and a middle portion located between the proximal and distal portions. The proximal and distal portions each comprise a mesh of support struts forming at least one ring of open elements disposed about the longitudinal axis. The middle portion features open regions which reduce or eliminate blockage of sensitive anatomical features at an implantation site.

Claims

1. A prosthetic apparatus comprising:

a tubular stent disposed about a longitudinal axis and extending from a proximal end to a distal end, the tubular stent defining a tubular passage between the ends;

wherein the tubular stent has a proximal portion, a distal portion, and a middle portion located between the proximal and distal portions;

wherein the proximal and distal portions each comprise a mesh of support struts forming at least one ring of open elements disposed about the longitudinal axis;

wherein the middle portion comprises;

a plurality of elongated posts extending along a direction substantially parallel the longitudinal axis between the proximal and distal portions; and

a crown shaped mounting ring attached to the posts and configured to mount a polymeric valve within the tubular passage; and

a plurality of open regions.

2. The apparatus of claim 1, wherein the open elements are open diamond shaped elements.

3. The apparatus of claim 2, wherein the plurality of open regions each define an open area along the outer surface of each support strut that is at least about 20 times the area of each of the open elements.

4. The apparatus of claim 3, wherein the plurality of open regions each define an open area along the outer surface of each support strut that is at least about 40 times the area of each of the open elements.

5. The apparatus of claim 3, wherein each of the proximal and distal portions comprise a ring of N open elements, the plurality of elongated posts consist of M posts extending between the rings, and the ratio of N to M is at least 4 to 1.

6. The apparatus of claim 5, wherein the ratio of N to M is at least 5 to 1.

7. The apparatus of claim 5, wherein the ratio of N to M is at least 6 to 1.

8. The apparatus of claim 6, wherein N=15 and M=3.

9. The apparatus of claim 1, further comprising a tubular polymeric sheath extending along the outer surface of each support strut from the proximal portion to the distal portion, but does not substantially cover the open regions in the middle portion.

10. The apparatus of claim 9, wherein the sheath encapsulates the elongated posts.

11. The apparatus of claim 10, wherein the sheath comprises regions of reinforced thickness corresponding to the elongated posts.

12. The apparatus of claim 10, wherein the sheath comprises regions of reinforced thickness corresponding to one or more of the support struts or the mounting ring.

13. The apparatus of claim 9, further comprising one or more sutures securing the sleeve to the stent.

14. The apparatus of claim 1, further comprising the polymeric heart valve, wherein the valve comprises:

a valve body having a central axis extending along the direction of the longitudinal axis of the tubular stent and having a body fluid pathway extending along the central axis from an inflow end to an outflow end;

a flexible outer support disposed about an outer circumference of the body and comprising at least three flexible valve posts each extending in the axial direction to a tip and each attached to at least one of the elongated posts; and

at least three flexible leaflets extending from the crown shaped mounting ring, each of the leaflets having an attached edge defining an attachment curve along the mounting ring extending between a respective pair of flexible valve posts, and wherein pairs of leaflets define a respective commissure at each of the at least three flexible valve posts;

wherein the crown shape ring comprises a plurality of points each corresponding to a flexible valve post and attached to a respective one of the elongated posts of the stent.

15. The apparatus of claim 14, wherein:

the at least three leaflets define a partially open position at rest, a fully open position deflecting away from the central axis during forward blood flow along a direction from the inflow end to the outflow end, and a closed position deflecting toward the central axis during reverse blood flow along a direction from the outflow end to the inflow end, and

in the closed position, each of the flexible valve posts flexes inward toward the central axis.

16. The apparatus of claim 15, wherein the tip of each valve post is formed of a material having a flexibility greater than the remainder of the valve post.

17. The apparatus of claim 16, wherein the stent is configured to be crimped to reduce the outer diameter of the stent from an uncrimped diameter to a crimped diameter without damaging the valve.

18. The apparatus of claim 17, wherein the uncrimped diameter is at least about 20 mm and the crimped diameter is less than about 6 mm.

19. The apparatus of claim 1, wherein the tubular stent comprises a shape memory material.

20. The apparatus of claim 19, wherein the shape memory material comprises Nitinol.

21. The apparatus of claim 1, wherein the stent is a self expanding stent.

22. The apparatus of claim 1, wherein the stent is configured such that, when implanted in the human heart such that the valve is positioned proximal the location of the native aortic valve, the open regions are positioned proximal to the coronary ostia.

23. The apparatus of claim 1, wherein the apparatus consists essentially of biocompatible materials.

24. A method comprising;

obtaining the apparatus of any preceding claim; and

percutaneously implanting the apparatus in a human subject such that that the valve is positioned proximal the location of the native aortic valve, the open regions are positioned proximal to the coronary ostia.

25. The method of claim 24, wherein the step of percutaneously implanting the apparatus comprises:

crimping the stent;

using an introducer to position the stent in a desired location; and

removing the introducer and expanding the stent to an uncrimped state.

26. The method of claim 25, wherein expanding the stent to an uncrimped state comprises allowing the stent to self expand.

27. A method of making prosthetic apparatus comprising:

obtaining a tubular stent disposed about a longitudinal axis and extending from a proximal end to a distal end, the stent defining a tubular passage between the ends;

wherein the tubular stent has a proximal portion, a distal portion, and a middle portion located between the proximal and distal portions;

wherein the proximal and distal portions each comprise a mesh of support struts forming at least one ring of open elements disposed about the longitudinal axis;

wherein the middle portion comprises;

a plurality of elongated posts extending along a direction substantially parallel the longitudinal axis between the proximal and distal portions; and

a crown shaped mounting ring attached to the posts and configured to mount a polymeric valve within the tubular passage; and

a plurality of open regions;

placing the stent on a mandrel;

forming a polymeric valve mounted on the mounting ring by a process comprising dip molding; and

forming a tubular polymeric sheath extending along the outer surface of each support strut from the proximal portion to the distal portion, but does not substantially cover the open regions in the middle portion.

28. The method of claim 27, wherein the step of forming the tubular polymeric sheath includes a thermoforming process comprising:

applying a polymer material to the outer surface of the tubular stent;

disposing a heat shrink tube about the polymer material and the stent; and

applying heat to soften the polymer material and cause the heat shrink tube to shrink and apply force to mold the polymer material to form the sheath.

29. The method of claim 28, wherein forming the sheath comprises encapsulating one or more of the support struts and the elongated posts.

30. The method of claim 28, further comprising, during the thermoforming process, applying an air flow to valve to avoid thermal damage to the valve.

31. The method of claim 27, further comprising:

applying strips of polymer material to reinforce the sheath at locations corresponding to the elongated posts or the mounting ring.

32. The method of claim 27, further comprising:

applying additional polymer material to reinforce the sheath at locations corresponding to the struts.