Stent covering formed of porous polytetraflouroethylene

• US 6,770,086 B1
• Filed: 11/02/2000
• Issued: 08/03/2004
• Est. Priority Date: 11/02/2000
• Status: Expired due to Term

• Current Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation)
• Original Assignee: Scimed Life Systems Incorporated (Boston Scientific Corporation)
• Inventors: Girton, Timothy Samuel
• Primary Examiner(s): Snow, Bruce
• Assistant Examiner(s): MILLER, CHERYL L
• Application Number:
  US09/704,494
• Time in Patent Office: 1,370 Days
• Field of Search: 623/1.13, 623/1.39, 623/1.4, 623/1.49, 623/901, 623/1.46, 623/1.44, 623/1.45
• US Class Current: 623/1.13
• CPC Class Codes: A61F 2/91 made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes
• CPC Class Codes: A61F 2/915 with bands having a meander structure, adjacent bands being connected to each other
• CPC Class Codes: A61F 2002/91541 Adjacent bands are arranged out of phase
• CPC Class Codes: A61F 2220/005 using adhesives
• CPC Class Codes: A61F 2220/0058 soldered or brazed or welded
• CPC Class Codes: A61F 2220/0066 stapled
• CPC Class Codes: A61F 2220/0075 sutured, ligatured or stitched, retained or tied with a rope, string, thread, wire or cable
• CPC Class Codes: A61L 31/048 obtained by reactions only involving carbon-to-carbon unsaturated bonds A61L31/041 takes precedence
• CPC Class Codes: A61L 31/146 Porous materials, e.g. foams or sponges
• CPC Class Codes: B29C 67/202 comprising elimination of a solid or a liquid ingredient
• CPC Class Codes: C08L 27/18 Homopolymers or copolymers or tetrafluoroethene

Abstract

A porous polytetrafluoroethylene substrate is used in an endoprosthesis device. An elongate radially expandable tubular stent is also included with the porous PTFE substrate, and form the endoprosthetic device. A method of making the porous polytetrafluoroethylene entails a novel method including siloxane in PTFE and thereafter removing the siloxane to form the porous structure. The PTFE structure does not have nodes and fibrils.

Claims

1. A method of covering an endoprosthesis device comprising the steps of:

providing an elongate radially expandable tubular stent;

providing a polytetrafluoroethylene having no node and fibril structure;

imparting porosity to said polytetrafluoroethylene by extracting siloxane from an interpenetrating network of siloxane and polytetrafluoroethylene;

forming a stent cover from said porous polytetrafluoroethylene; and

applying said stent cover to an interior surface and exterior surface, or both of said stent wherein said stent cover extends along a longitudinal stent axis.

2. The method of claim 1 wherein said stent cover is applied to said interior surface and to said exterior surface of said stent.

3. The method of claim 1 wherein said stent cover is fixed to said stent using an adhesive.

4. The method of claim 3 wherein said adhesive is selected from the group consisting of polyurethanes, epoxies, cyanoacrylates, polyamides, polyimides, and silicones.

5. The method of claim 1 wherein said stent cover is fixed to said stent by a welding process, said welding process comprising heating the polytetrafluoroethylene stent cover to a temperature that is greater than the sintering temperature of the polytetrafluoroethylene.

6. The method of claim 1 wherein said siloxane is polydimethylsiloxane.