Foam-type vascular prosthesis with well-defined angio-permissive open porosity

• US 7,632,306 B2
• Filed: 07/02/2003
• Issued: 12/15/2009
• Est. Priority Date: 07/20/1999
• Status: Expired due to Fees

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Zilla, Peter Paul, Bezuidenhout, Deon
• Primary Examiner(s): TRUONG, KEVIN THAO
• Application Number:
  US10/612,082
• Publication Number:
  US 20040006383A1
• Time in Patent Office: 2,358 Days
• Field of Search: 623/1.39, 623/1.4, 623/1.41, 623/1.46, 623/1.44, 623/1.23, 623/1.33, 623/1.32, 521/92, 521/138, 521/139, 521/180, 521/182
• US Class Current: 623/1.39
• CPC Class Codes: A61F 2/0077 Special surfaces of prostheses, e.g. for improving ingrowth A61F2/30767 takes precedence
• CPC Class Codes: A61F 2/06 Blood vessels
• CPC Class Codes: A61L 27/18 obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: A61L 27/507 for artificial blood vessels apparatus for applying cells on a blood vessel prosthesis A61F2/062
• CPC Class Codes: A61L 27/56 Porous materials, e.g. foams or sponges
• CPC Class Codes: C08L 75/04 Polyurethanes

Abstract

A vascular prosthesis is constructed from a well-defined pore structure to allow uninterrupted ingrowth of connective tissue into a wall of the prosthesis. Several different methods can be used to produce the prosthesis, including a vacuum impregnation technique, a paste molding technique, a paste extrusion technique, a dip coating technique, and a melt extrusion technique. Furthermore, mechanical properties of the prosthesis are matched with mechanical properties of the host vessel, thereby overcoming problems of compliance mismatch.

Claims

1. A method of making a prosthesis comprising the steps of:

extruding a thermoplastic elastomer with the aid of a blowing agent, to produce a foamed graft; and

reticulating the foamed graft to effect an open-cell structure.

2. The method of claim 1 wherein the blowing agent comprises a physical blowing agent.

3. The method of claim 2, wherein the physical blowing agent is selected from the group consisting of chlorofluorocarbons, pentane, hexane and combinations thereof.

4. The method of claim 1 wherein the blowing agent comprises a chemical blowing agent.

5. The method of claim 4, wherein the chemical blowing agent is selected from the group consisting of sodium bicarbonate, azodicarbonamides and combinations thereof.

6. The method of claim 1 wherein the blowing agent comprises physical and chemical blowing agents.

7. The method of claim 1 wherein the thermoplastic elastomer comprises a polyurethane.

8. The method of claim 7, wherein the polyurethane is selected from the group consisting of Pellethane, Biomer type polyurethanes, Chronoflex, Hydrothane and combinations thereof.

9. The method of claim 1 wherein the thermoplastic elastomer further comprises reinforcing fibers.

10. A biosynthetic heart valve made according to the method of claim 1.

11. A sewing ring made according to the method of claim 1.

12. A stent made according to the method of claim 1.

13. A vascular graft prosthesis made according to the method of claim 1.

14. The method of claim 1, comprising annealing the foamed graft to effect the open-cell structure.