Prosthetic heart valve with improved blood flow

• US 5,908,452 A
• Filed: 02/20/1998
• Issued: 06/01/1999
• Est. Priority Date: 05/16/1995
• Status: Expired due to Term

• Current Assignee: Valve Special Purpose Co. LLC (Cryolife Incorporated)
• Original Assignee: On-X Life Technologies, Inc. (Cryolife Incorporated)
• Inventors: Waits, C. Thomas, Peters, T. Scott, Stupka, Jonathan C., Bokros, Jack C., Emken, Michael R., Ely, John L., Haubold, Axel D.
• Primary Examiner(s): Yu, Mickey
• Assistant Examiner(s): CUDDIHY, FRANCIS KEVIN
• Application Number:
  US09/027,358
• Time in Patent Office: 466 Days
• Field of Search: 623/1, 623/2, 623/900, 137/527
• US Class Current: 623/2.31
• CPC Class Codes: A61F 2/0077 Special surfaces of prostheses, e.g. for improving ingrowth A61F2/30767 takes precedence
• 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 2310/00161 Carbon; Graphite
• CPC Class Codes: A61F 2310/00173 Graphite
• CPC Class Codes: A61F 2310/00574 Coating or prosthesis-covering structure made of carbon, e.g. of pyrocarbon
• CPC Class Codes: Y10S 623/90 Stent for heart valve

Abstract

A prosthetic heart valve is shown which incorporates a valve body design and leaflet pivot arrangements that minimize turbulence and shear stresses having a tendency to generate thrombosis. A valve body having an axially curved entrance that is smoothly joined to a generally cylindrical body of extended axial length provides excellent fluid flow characteristics when combined with leaflets that can assume orientations perfectly aligned with the downstream flow of blood. By constructing such a pyrocarbon valve body which receives a metal ring at an appropriate location, suture rings that permit the tissue annulus to directly contact the exterior surface of the cylindrical valve body are accommodated.

Claims

1. A prosthetic heart valve which comprises

a generally tubular valve body having an upstream end, a downstream end and an interior sidewall which defines a central passageway therethrough for blood flow in a downstream direction, said passageway having an axial centerline and being generally circular in cross section,

means associated with the exterior of said tubular valve body for mounting said valve in association with a human heart,

at least one occluder having an inflow surface and an outflow surface, said occluder being mounted within said valve body to open and close so as to alternately permit flow of blood therethrough in a downstream direction when in an open orientation and to block reverse flow of blood in an upstream direction when in a closed orientation, and

a pivot arrangement by which said occluder is associated with the interior of said valve body and by which said occluder is guided in movement between said open and closed orientations,

said valve body having an upstream entrance end section formed with an interior surface that has a radius of curvature in a plane which contains said axial centerline between about 28% and about 80% of said central passageway radius, which entrance end section connects to a downstream cylindrical section,

whereby downstream blood flow through said valve central passageway in said open orientation is of a streamlined nature.

2. The prosthetic heart valve of claim 1 wherein said downstream cylindrical section has a cylindrical exterior surface of exterior diameter D_v extending to said downstream end, and wherein said upstream entrance end section has an exterior diameter that is at least about 6% greater than D_v.

3. The prosthetic heart valve according to claim 1 wherein said occluder has rectilinear outflow and inflow surfaces and wherein said pivot arrangement permits said occluder to assume an alignment so that said inflow and outflow surfaces are substantially parallel to said valve passageway axial centerline when said occluder is in said open orientation.

4. The prosthetic heart valve according to claim 3 wherein said at least one occluder comprises two leaflets, wherein said valve body is formed with a pair of diametrically opposed flat interior sidewall surfaces and wherein said downstream cylindrical section of said valve body terminates in a pair of diametrically opposed shallow notches which provide openings for the reverse flow of blood laterally into a central portion of the valve passageway, said lateral openings being aligned with said valve body flat interior sidewall surfaces.

5. The prosthetic heart valve according to claim 1 wherein said curved entrance end section is essentially a section of a torus having an interior diameter generally equal to between about 80% and 120% of a diameter of said generally circular central passageway.

6. The prosthetic heart valve according to claim 5 wherein said upstream entrance end section comprises a section of a torus extending axially for a distance between about 10% and about 33% of an average axial length of said tubular valve body.

7. The prosthetic heart valve according to claim 6 wherein said torus has an interior diameter equal to about a diameter of said generally circular central passageway and wherein said diameter of the upstream edge of said entrance end section is not more than about 10% greater than the exterior diameter of said downstream cylindrical section.

8. A prosthetic heart valve which comprises

a generally tubular valve body having an interior sidewall which defines a central passageway therethrough for blood flow in a downstream direction, said passageway having an axial centerline and being generally circular in cross section,

means associated with said tubular valve body for mounting said valve in association with a human heart,

at least two leaflets, each having an inflow surface and an outflow surface, said leaflets being mounted in said valve body to open and close together to alternately permit flow of blood therethrough in a downstream direction when in an open orientation and to block the reverse flow of blood in an upstream direction when in a closed orientation, and

a pivot arrangement by which said leaflets are guided in movement between said open and closed orientations, said pivot arrangement being such that said outflow and inflow surfaces may assume an alignment substantially parallel to said valve passageway axial centerline when said leaflets are in a fully open orientation,

said valve body having an upstream entrance end section formed with an interior surface that has a radius of curvature in a plane which contains said axial centerline between about 28% and about 80% of said central passageway radius, which entrance end connects to a downstream cylindrical section,

whereby downstream blood flow through said valve central passageway in said open orientation is of a streamlined nature and pressure drop across said heart valve is low.

9. The prosthetic heart valve according to claim 8 wherein said upstream entrance end section comprises a section of a torus having an interior diameter generally equal to between about 80% and 120% of a diameter of said generally circular central passageway.

10. The prosthetic heart valve according to claim 9 wherein said upstream entrance end section comprises a section of a torus extending axially for a distance between about 10% and about 33% of an average axial length of said tubular valve body.

11. The prosthetic heart valve according to claim 8 wherein the valve has exactly two leaflets, and wherein the downstream end of said valve body is formed with a pair of diametrically opposed shallow notches providing lateral openings for the reverse flow of blood into the central portion of the valve passageway, which lateral openings are generally aligned with axes upon which said leaflets pivot as established by said pivot arrangement.

12. A prosthetic heart valve for replacement of a defective aortic valve comprising

a generally tubular valve body having an interior sidewall which defines a central passageway therethrough for blood flow in a downstream direction, said passageway having an axial centerline and being generally circular in cross section having a first radius,

suture ring means located on the exterior surface of said tubular valve body for mounting said valve in association with a human heart,

occluder means having an inflow surface portion and an outflow surface portion, which occluder means is mounted in said valve body to open and close to alternately permit flow of blood therethrough in a downstream direction when in an open orientation and to block the reverse flow of blood in an upstream direction when in a closed orientation, and

a pivot arrangement by which said occluder means is guided in movement between said open and closed orientations,

said valve body having an upstream entrance end section formed with an interior surface that has a radius of curvature in a plane which contains said axial centerline between about 28% and about 80% of said first radius, which entrance end section connects to a downstream cylindrical section, whereby downstream blood flow through said valve central passageway in said open orientation is of a streamlined nature so pressure drop across said heart valve is low,

said entrance end section having an exterior circumferential surface that is concave and toroidal, and

said suture ring means being so located axially along said exterior surface of said valve body that a tissue annulus raw edge lies in direct contact with said concave toroidal exterior circumferential surface when said heart valve is implanted in a patient.

13. The prosthetic heart valve according to claim 12 wherein a major portion of said upstream entrance end section of said valve body is of substantially constant thickness and wherein both said interior surface and said exterior surface of said entrance end section are in the form of at least 30% of a quadrant of a torus.