Artificial heart valves

• US 4,490,859 A
• Filed: 01/18/1983
• Issued: 01/01/1985
• Est. Priority Date: 01/20/1982
• Status: Expired due to Fees

• Current Assignee: University of Sheffield
• Original Assignee: University of Sheffield
• Inventors: Black, Martin M., Drury, Philip J.
• Primary Examiner(s): FRINKS, RONALD
• Application Number:
  US06/459,037
• Time in Patent Office: 714 Days
• Field of Search: 3/1.5, 3/1
• US Class Current: 623/2.16
• 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

Abstract

A bioprosthetic mitral valve replacement comprises a flexible frame (1) having a ring-shaped base (2) and at least a pair of upstanding posts (3), which divide the base into at least two portions (2A, 2B) of varying flexibility, together with animal tissue leaflets (4) each having a periphery consisting of a free portion (4A) extending between the tips (3X) of posts (3) and a fixed portion (4B) secured and sealed to corresponding sides of the posts and the adjacent portion of the base. A bicuspid mitral valve replacement has a pair of posts (3) disposed at opposite ends of a diameter of the undistorted base (2), or displaced therefrom towards the portion (2A) of lesser flexibility to accommodate leaflets (4) of unequal size. The frame (1) is formed of Delrin covered with Dacron cloth, the Delrin having differing thicknesses to either side of the posts (3) which merge into the base (2) by way of a continuous curve (6) on each side. The leaflets (4) are cut from flat sheet in a special way to avoid stress-fixing.

Claims

1. A bioprosthetic mitral valve replacement comprising a frame having a ring-shaped base and at least a pair of upstanding posts merging into the base by way of a continuous curve from the tip of one post to the tip of the other post, valve leaflets each having a free portion extending between the tips of the posts and a fixed portion secured and sealed to corresponding sides of the posts and the adjacent portion of the base, the valve leaflets being cut from a flat sheet of fully fixed animal tissue and the shape of each leaflet corresponding to a portion of a surface of a cone which portion is defined by the intersections on the conical surface of two parallel flat planes having peripheries on the conical surface corresponding in length respectively to the circumference of the ring-shaped base and the distance between the tips of the posts of the frame, and a third intersection on the conical surface of a curved plane concave towards the apex of the cone and intersecting the two parallel flat planes at opposite sides of the cone, the spacing of the flat planes and the curvature of the curved plane being such that the development of the curved plane on the conical surface matches in length and curvature the continuously blending curve of one arcuate portion of the ring-shaped base and the adjacent sides of the posts.

2. A mitral valve replacement as in claim 1, wherein the base is flexible and a pair of upstanding posts divide the base into two portions of differing flexibility, with lesser flexibility at one side between the posts than at the other side between the posts.

3. A mitral valve replacement as in claim 2, wherein the posts are disposed at opposite ends of a diameter of the undistorted base.

4. A mitral valve replacement as in claim 2, wherein the posts are displaced from the opposite ends of a diameter of the undistorted base towards the portion of lesser flexibility, and the leaflets are of correspondingly equal size.

5. A mitral valve replacement as in claim 1, wherein three posts are disposed at regular intervals round the base.

6. A mitral valve replacement as in claim 1, wherein the frame is formed of polyformaldehyde covered with polyethylene terephthalate cloth.

7. A mitral valve replacement as in claim 2, wherein the differential flexibility is afforded by providing differing thicknesses of polyformaldehyde to either side of the posts.