Low Gradient Prosthetic Heart Valve

• US 20110282440A1
• Filed: 05/11/2011
• Published: 11/17/2011
• Est. Priority Date: 05/12/2010
• Status: Active Grant

• Current Assignee: Edwards Lifesciences Corporation
• Original Assignee: Edwards Lifesciences Corporation
• Inventors: Sun, Wei, Cao, Hengchu
• Granted Patent: US 9,554,901 B2
• Time in Patent Office: Days
• US Class Current: 623/2.18
• 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 2210/0014 using shape memory or superelastic materials, e.g. nitinol
• CPC Class Codes: A61F 2220/0075 sutured, ligatured or stitched, retained or tied with a rope, string, thread, wire or cable
• CPC Class Codes: A61L 27/3625 Vascular tissue, e.g. heart valves

Abstract

A low pressure gradient prosthetic heart valve for implant in a human. The valve includes a support frame with undulating inflow cusps and outflow commissure posts to which flexible leaflets attach and coapt in a flow area. The commissure posts angle outward in a neutral state to widen the outflow orifice area. Also, the leaflets are designed to fit within the support frame and expand outward in a valve open state without creating a shelf or belly that would restrict flow.

Claims

1. A low pressure gradient prosthetic heart valve, comprising:

a support frame including an undulating leaflet attachment edge with alternating arcuate inflow cusps and arcuate outflow commissures ending in tips, the leaflet attachment edge in a relaxed state of the support frame circumscribing a flow volume having a central axis, the flow volume having a maximum flow orifice area perpendicular to the central axis limited by the inflow end of the support frame; and

a plurality of flexible leaflets attached to the support frame and extending inward toward the axis, each leaflet having an arcuate cusp edge that conforms to a corresponding support frame cusp and attaches therealong between adjacent commissures, and a free edge that coapts with the free edges of the other leaflets to provide one way flow through the valve,

wherein when the valve opens the free edges of the leaflets move outward toward the generally tubular shape described by the support frame from fluid flow in an outflow direction and corresponding fluid pressures, and wherein each commissure of the relaxed support frame is angled radially outward so as to provide an outflow orifice area greater than the maximum flow orifice area and induce laminar flow through the valve.

2. The heart valve of claim 1, wherein the radially outward angle made by each commissure is α

=4±

3°

.

3. The heart valve of claim 1, wherein the inflow cusps of the support frame define an inflow plane having an inflow diameter Φ

_i circumscribed by the nadirs of the cusps, and the commissures of the support frame have an axial height H from the inflow plane to their tips that satisfies the following relationship;

4. The heart valve of claim 3, wherein the heart valve leaflets have a coaptation point along the central axis where all three leaflets meet upon valve closing, and a coaptation height h from the inflow plane to the coaptation point that satisfies the following relationship:

5. The heart valve of claim 1, wherein the support frame comprises an elongated rod-like member made out of an elastic material.

6. The heart valve of claim 5, wherein the support frame is formed as a continuous piece of Nitinol with no breaks or crimp.

7. The heart valve of claim 6, wherein the commissures of the support frame each include an upstanding bar and a series of through holes therein that provide anchor points for other elements of the heart valve.

8. The heart valve of claim 1, wherein each leaflet has a size and is attached to the corresponding support frame cusp such that when the valve opens the leaflets spread outward to provide an outflow orifice area that is no less than the maximum flow orifice area.

9. The heart valve of claim 1, wherein each leaflet has opposed attachment tabs disposed between its arcuate cusp edge and its free edge, the leaflet having a central area subject to stress when secured within a surrounding heart valve support frame, the leaflet being symmetric about a central plane and the arcuate cusp edge being defined by a complex curve of multiple radii, the complex curve having a smaller radius that gradually decreases on both sides away from the central plane, reaches a maximum at about 45°

angle from the central axis, and gradually increases to two corners where the two ends of the arcuate cusp edge meet the attachment tabs.

10. A low pressure gradient prosthetic heart valve, comprising:

a support frame including an undulating leaflet attachment edge with alternating arcuate inflow cusps and arcuate outflow commissures, the leaflet attachment edge circumscribing a flow volume having a central axis, the flow volume having a maximum flow orifice area perpendicular to the central axis limited by the inflow end of the support frame;

a plurality of flexible leaflets attached to the support frame and extending inward toward the axis, each leaflet having an arcuate cusp edge that conforms to a corresponding support frame cusp and attaches therealong between adjacent commissures, and a free edge that coapts with the free edges of the other leaflets to provide one way flow through the valve,

wherein when the valve opens the free edges of the leaflets move outward toward the flow volume described by the support frame from fluid flow in an outflow direction and corresponding fluid pressures, and wherein each leaflet has a size and is attached to the corresponding support frame cusp such that when the valve opens the leaflets spread outward to provide an outflow orifice area that is no less than the maximum flow orifice area.

11. The heart valve of claim 10, wherein the support frame has a relaxed state and each commissure of the relaxed support frame is angled radially outward so as to provide an outflow orifice area greater than the maximum flow orifice area and induce laminar flow through the valve.

12. The heart valve of claim 10, wherein the inflow cusps of the support frame reside in an inflow plane within which is defined an inflow diameter Φ

_i circumscribed by the nadirs of the cusps, and the commissures of the support frame have an axial height H from the inflow plane to their tips that satisfies the following relationship;

13. The heart valve of claim 12, wherein the heart valve leaflets have a coaptation point along the central axis where all three leaflets meet upon valve closing, and a coaptation height h from the inflow plane to the coaptation point that satisfies the following relationship:

14. The heart valve of claim 10, wherein the support frame comprises an elongated rod-like member made out of an elastic material.

15. The heart valve of claim 14, wherein the support frame is formed as a continuous piece of Nitinol with no breaks or crimp.

16. The heart valve of claim 15, wherein the commissures of the support frame each include an upstanding bar and a series of through holes therein that provide anchor points for other elements of the heart valve.

17. A leaflet for a low pressure gradient prosthetic heart valve, comprising:

a flexible leaflet having an arcuate cusp edge opposite a free edge and opposed attachment tabs therebetween, the leaflet having a central area subject to stress when secured within a surrounding heart valve support frame, the leaflet being symmetric about a central midplane and the arcuate cusp edge being defined by a complex curve of multiple radii, the complex curve having its smallest radius on the central midplane that gradually increases on both sides away from the central plane, reaches a maximum at about 45°

angle from the central axis, and then gradually decreases to two corners where the two ends of the arcuate cusp edge meet the attachment tabs.

18. The leaflet of claim 17, wherein the free edge diverges above a straight line drawn between the side tabs to form a supplemental strip of leaflet material that gradually widens as it progresses inward from the tabs until it forms a plateau for a majority of its length, and then rapidly widens in converging curves that lead to an apex on the vertical midplane.

19. The leaflet of claim 17, wherein the free edge diverges above a straight line drawn between the side tabs to form a supplemental strip of leaflet material shaped generally as a triangle with an apex on the vertical midplane.

20. The leaflet of claim 17, wherein the leaflet is cut from bovine pericardium.