Method of manufacture of a heart valve support frame

• US 7,318,278 B2
• Filed: 01/03/2005
• Issued: 01/15/2008
• Est. Priority Date: 09/20/2002
• Status: Expired due to Term

• Current Assignee: Edwards Lifesciences Corporation
• Original Assignee: Edwards Lifesciences Corporation
• Inventors: Shrivastava, Sanjay, Denton, Melissa, Zhang, Xiangyang, Desai, Pranav
• Primary Examiner(s): Omgba; Essama
• Application Number:
  US11/028,878
• Publication Number:
  US 20050150775A1
• Time in Patent Office: 1,107 Days
• Field of Search: 294/58, 298/901.2, 294/47, 623/2.11, 623/2.42, 205/685, 205/704, 205/705, 205/711, 205/716, 205/727
• US Class Current: 29/890.12
• 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 2/2415 Manufacturing methods
• CPC Class Codes: A61F 2/2418 Scaffolds therefor, e.g. support stents
• CPC Class Codes: A61F 2220/0075 sutured, ligatured or stitched, retained or tied with a rope, string, thread, wire or cable
• CPC Class Codes: Y10T 29/49405 Valve or choke making
• CPC Class Codes: Y10T 29/49865 by temperature differential [e.g., shrink fit]
• CPC Class Codes: Y10T 29/49885 with coating before or during assembling
• CPC Class Codes: Y10T 29/49895 Associating parts by use of aligning means [e.g., use of a drift pin or a "fixture"]
• CPC Class Codes: Y10T 29/49904 Assembling a subassembly, then assembling with a second subassembly
• CPC Class Codes: Y10T 29/49906 Metal deforming with nonmetallic bonding
• CPC Class Codes: Y10T 29/49995 Shaping one-piece blank by removing material

Abstract

Methods for forming a support frame for flexible leaflet heart valves from a starting blank include converting a two-dimensional starting blank into the three-dimensional support frame. The material may be superelastic, such as NITINOL, and the method may include bending the 2-D blank into the 3-D form and shape setting it. A merely elastic material such as ELGILOY may be used and plastically deformed in stages, possibly accompanied by annealing, to obtain the 3-D shape. Alternatively, a tubular blank could be formed to define a non-tubular shape, typically conical. A method for calculating the precise 2-D blank shape is also disclosed. A mandrel assembly includes a mandrel and ring elements for pressing the blank against the external surface of the mandrel prior to shape setting.

Claims

1. A method of forming a heart valve support frame, comprising:

providing a heart valve support frame having an undulating shape with three cusps and three commissures; and

electropolishing the heart valve support frame by twice rotating the heart valve support frame 120°

from an initial position during the electropolishing process to ensure symmetric material removal.

2. The method of claim 1, wherein the heart valve support frame is metallic and has a rectilinear cross-section.

3. The method of claim 1, wherein the heart valve support frame is made of NITINOL.

4. The method of claim 1, further including:

prior to electropolshing, first removing oxidation from an outer surface of the heart valve support frame.

5. The method of claim 4, wherein the step of removing oxidation comprises microblasting the outer surface of the heart valve support frame.

6. The method of claim 1, wherein the step of electropolishing comprises:

submerging the heart valve support frame into a conductive fluid bath;

providing an anode and a cathode; and

flowing a current between the anode and the cathode to electropolish the heart valve support frame.

7. The method of claim 6, wherein the step of providing an anode comprises positioning plate anodes within the conductive fluid bath around the heart valve support frame.

8. The method of claim 6, wherein the conductive fluid bath comprises nitric acid and methanol.

9. The method of claim 6, wherein the conductive fluid bath is maintained at a temperature of between about −

28 to −

32°

C.

10. The method of claim 6, wherein the conductive fluid bath is maintained at a conductivity level of between about 140-190 μ

s at 23°

C.

11. The method of claim 6, wherein the current flows at a voltage of between about 9-10 V.

12. The method of claim 1, wherein each commissure is formed by a pair of generally asymptotic regions projecting from the adjacent cusps and a tip region, the method further comprising holding the heart valve support frame at three of the asymptotic regions.

13. A method of forming a heart valve support frame, comprising:

providing a heart valve support frame having an undulating shape with three cusps separated by three commissures;

submerging the heart valve support frame into a conductive fluid bath;

within the conductive fluid bath, holding the heart valve support frame at discrete points around the undulating shape;

providing an anode and a cathode and flowing a current between the anode and the cathode to electropolish the heart valve support frame within the conductive fluid bath; and

twice rotating the heart valve support frame 120°

from an initial position during the electropolishing process to ensure symmetric material removal.

14. The method of claim 13, wherein the heart valve support frame is made of NITINOL.

15. The method of claim 13, wherein the step of providing an anode comprises positioning plate anodes within the conductive fluid bath around the heart valve support frame.

16. The method of claim 13, further comprising:

holding the heart valve support frame at just three points around the undulating shape.

17. The method of claim 13, wherein each commissure is formed by a pair of generally asymptotic regions projecting from the adjacent cusps and a tip region, the method further comprising:

holding the heart valve support frame at three of the asymptotic regions.