Support structure/membrane composite medical device

• US 6,699,276 B2
• Filed: 02/16/2000
• Issued: 03/02/2004
• Est. Priority Date: 09/26/1996
• Status: Expired due to Fees

• Current Assignee: Lifeshield Sciences LLC (Acacia Research Corporation)
• Original Assignee: Scimed Life Systems Incorporated (Boston Scientific Corporation)
• Inventors: Smith, Scott R., Sogard, David, Shoemaker, Susan
• Primary Examiner(s): SNOW, BRUCE EDWARD
• Application Number:
  US09/505,158
• Publication Number:
  US 20020045931A1
• Time in Patent Office: 1,476 Days
• Field of Search: 623/1.13, 623/1.44, 623/1.46, 623/901, 156/547, 156/294
• US Class Current: 623/1.13
• CPC Class Codes: A61F 2/07 Stent-grafts
• CPC Class Codes: A61F 2/848 having means for fixation to the vessel wall, e.g. barbs
• CPC Class Codes: A61F 2/90 characterised by a net-like or mesh-like structure
• 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 2002/072 Encapsulated stents, e.g. wire or whole stent embedded in lining
• CPC Class Codes: A61F 2002/075 the stent being loosely attached to the graft material, e.g. by stitching
• CPC Class Codes: A61F 2002/91541 Adjacent bands are arranged out of phase
• CPC Class Codes: A61F 2002/91558 connected peak to peak
• CPC Class Codes: Y10T 156/1722 Means applying fluent adhesive or adhesive activator material between layers

Abstract

The present invention relates to a support structure/membrane composite device which includes a support structure, such as a radially expandable stent, a porous non-textile polymeric membrane adjacent to said stent and a thermoplastic anchor means attaching said stent to said porous non-textile polymeric membrane. The porous non-textile polymeric membrane is preferably made from expandable fluoropolymer materials. The anchoring means is a thermoplastic material which is dissolvable at the interface between the support structure and membrane by a suitable solvent which wets the membrane surface and deposits the thermoplastic material within the pores of the membrane. Methods of preparing the device are also disclosed.

Claims

1. A method of making an implantable support structure/membrane composite medical device comprising the step of:

(i) providing a support structure;

(ii) coating at least a portion of said support structure with a thermoplastic anchoring material;

(iii) positioning a porous non-textile polymeric membrane in intimate contact with said anchoring material to form an interface therebetween;

(iv) dissolving with a suitable solvent at least a portion of said anchoring material at said interface to cause penetration of said anchoring material into said porous non-textile polymeric membrane; and

(v) removing said solvent to allow resolidification of said anchoring material within said porous non-textile polymeric membrane, thereby anchoring said support structure to said porous non-textile polymeric membrane.

2. The method of claim 1 wherein said thermoplastic anchoring material is selected from the group consisting of polyurethanes, silicones, bioresorbable polymers and mixtures thereof.

3. The method of claim 1 wherein said solvent is a wetting agent for said porous non-textile polymeric membrane.

4. The method of claim 1 wherein said solvent is selected from the group consisting of dimethylacetamide, tetrahydrofuran, ether, chloroform, methylene chloride, toluene, and mixtures thereof.

5. The method of claim 1 wherein said porous non-textile polymeric membrane is selected from the group consisting of fluoropolymers, polyurethanes and polyimides.

6. The method of claim 5 wherein said porous non-textile polymeric membrane is ePTFE.

7. The method of claim 6 wherein said porous non-textile polymeric membrane is a pre-formed ePTFE.

8. The method of claim 1 wherein said support structure is a material selected from the groups consisting of biocompatible metals and thermoplastic polymers.

9. The method of claim 8 where in said support structure is a stent.

10. The method of claim 9 wherein said stent is radially expandable by a balloon catheter or by a self-expanding mechanism.

11. The method of claim 10 wherein said stent is made from nitinol.

12. A method of anchoring an endovascular stent to a porous biocompatible fluoropolymer membrane comprising the steps of:

(i) providing a radially expandable endovascular stent having a solid thermoplastic anchoring material on its surface;

(ii) positioning said porous biocompatible fluoropolymer membrane in intimate contact with said anchoring material to form an interface therebetween;

(iii) applying a suitable solvent for said anchoring material which wets said fluoropolymer membrane surface to cause flow of at least a portion of said anchoring material into said porous biocompatible membrane;

(iv) removing said solvent to resolidify said anchoring material within said porous biocompatible membrane, thereby anchoring said stent to said membrane.

13. The method of claim 12 wherein said anchoring material is selected from the group consisting of polyurethanes, silicones, bioresorbable polymers and mixtures thereof.

14. The method of claim 12 wherein said fluoropolymer membrane is ePTFE.

15. The method of claim 12 wherein said solvent is selected from group consisting of dimethylacetamide, tetrahydrofuran, ether, chloroform, methylene chloride, toluene and mixtures thereof.

16. A method of forming a stent graft assembly, the method comprising the steps of:

providing a generally cylindrical stent having an interior and an exterior, first and second ends and at least one support member;

coating at least a portion of at least one support member with a coating to substantially encapsulate at least a portion of the at least one support member;

providing at least one membrane;

placing said at least one membrane contiguous with at least a portion of at least one of the exterior and interior of the stent;

introducing a solvent in order to bond the membrane to the coating; and

removing the solvent.

17. The method of claim 16 wherein the step of coating the stent is performed by spraying a polymeric solution onto the stent.

18. The method of claim 16 wherein the step of coating the stent comprises a vapor deposition process.

19. The method of claim 16 wherein the step of coating the stent comprises dipping the stent into a polymeric solution.

20. The method of claim 16 wherein the stent-graft assembly also comprises a medial region, a proximal region and a distal region, with the additional step of coating the proximal and distal regions of the stent-graft assembly.

21. The method of claim 20 wherein the step of coating the distal and proximal regions comprises dipping the proximal and distal regions of the assembly into a polymer in solution.