Cardiovascular graft and method of forming same

• US 4,657,544 A
• Filed: 04/18/1984
• Issued: 04/14/1987
• Est. Priority Date: 04/18/1984
• Status: Expired due to Term

• Current Assignee: Lifeshield Sciences LLC (Acacia Research Corporation)
• Original Assignee: Cordis Corporation (Cardinal Health, Inc.)
• Inventors: Pinchuk, Leonard
• Primary Examiner(s): FRINKS, RONALD
• Application Number:
  US06/601,676
• Time in Patent Office: 1,091 Days
• Field of Search: 623/1, 623/12
• US Class Current: 623/1.39
• CPC Class Codes: A61F 2/06 Blood vessels
• CPC Class Codes: A61L 27/14 Macromolecular materials
• CPC Class Codes: A61L 27/16 obtained by reactions only involving carbon-to-carbon unsaturated bonds
• 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: B29C 2045/1719 making tubular articles
• CPC Class Codes: B29K 2995/0056 Biocompatible, e.g. biopolymers or bioelastomers
• CPC Class Codes: B29L 2023/007 Medical tubes other than catheters catheters B29L2031/7542
• CPC Class Codes: B29L 2031/7534 Cardiovascular protheses
• CPC Class Codes: C08J 9/24 by surface fusion and bonding of particles to form voids, e.g. sintering of expandable particles C08J9/232
• CPC Class Codes: C08J 9/26 by elimination of a solid phase from a macromolecular composition or article, e.g. leaching out
• CPC Class Codes: C08L 27/18 Homopolymers or copolymers or tetrafluoroethene
• CPC Class Codes: C08L 75/04 Polyurethanes
• CPC Class Codes: C08L 83/04 Polysiloxanes

Abstract

The graft is particularly adapted for cardiovascular use and comprises a tube which has been reaction injection molded, cast molded, or extruded from a nonsolvent, two component hydrophobic biocompatible polymer system, which is initially formed with water soluble inorganic salt crystals mixed with the system, and which has a honeycomb of interconnecting cells throughout the thickness of the wall of the tube formed by the leaching of the water soluble inorganic salt crystals from the tube.

Claims

1. A graft particularly adapted for cardiovascular use, said graft comprising a tube which has been reaction injection molded, cast molded, or extruded from a nonsolvent, two component hydrophobic biocompatible polymer system, which is initially formed with water soluble inorganic salt crystals mixed with the system, and which has a honeycomb of interconnecting cells throughout the thickness of the wall of the tube formed by the leaching of said water soluble inorganic salt crystals from the tube.

2. The graft of claim 1 wherein the biocompatible polymer system is a polymer resin and curing agent.

3. The graft of claim 2 wherein said polymer resin is chosen from the group comprising polyurethane, silicone and polytetrafluoroethylene (Teflon).

4. The graft of claim 2 wherein said curing agent is chosen from the group comprising platinum, tempered steel heat, cross linkers, gamma radiation and ureaformaldehyde.

5. The graft of claim 1 wherein said inorganic salt crystals are sized to provide cells in the tube of predetermined size.

6. The graft of claim 5 wherein said inorganic salt crystals are sodium chloride crystals.

7. The graft of claim 1 wherein said inorganic salt crystals are dried crystals which have been dried at a temperature between 100°

and 175°

C. for a minimum of twenty-four hours.

8. The graft of claim 7 wherein said temperature is approximately 135°

C.

9. The graft of claim 1 wherein said crystals have a predetermined mesh size.

10. The graft of claim 9 wherein said mesh size is between approximately 10 and 200 microns.

11. The graft of claim 1 wherein the concentration of water soluble inorganic salt crystals relative to said biocompatible polymer system in the initially formed tube is between approximately 25% and 75% by weight.

12. The graft of claim 11 wherein said range is determined by the required flexibility and/or porosity of the graft to be fabricated.

13. The graft of claim 1 wherein said cells are of a uniform diameter within the graft.

14. The graft of claim 13 wherein the diameter of the cells in the graft is between approximately 10 and 200 microns.

15. The graft of claim 1 wherein the wall thickness of the graft is between approximately 0.5 cm and 4 cm depending on the location at which the graft is to be used within the cardiovascular system.

16. The graft of claim 1 wherein the concentration of water soluble inorganic salt crystals relative to said biocompatible polymer system in the initially formed tube is greater than 50% but less than 90% by weight.