Carbon containing vascular graft and method of making same

• US 5,827,327 A
• Filed: 01/03/1997
• Issued: 10/27/1998
• Est. Priority Date: 09/23/1994
• Status: Expired due to Term

• Current Assignee: Bard Peripheral Vascular Incorporated (Becton, Dickinson & Co)
• Original Assignee: IMPRA Incorporated (Becton, Dickinson & Co)
• Inventors: McHaney, James M., Banas, Christopher E.
• Primary Examiner(s): Milano, Michael J.
• Application Number:
  US08/777,006
• Time in Patent Office: 662 Days
• Field of Search: 623/1, 623/11, 623/12
• US Class Current: 623/1.44
• CPC Class Codes: A61F 2/06 Blood vessels
• CPC Class Codes: B29C 48/022 characterised by the choice of material
• CPC Class Codes: B29C 48/06 Rod-shaped
• CPC Class Codes: B29C 48/09 Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
• CPC Class Codes: B29C 55/005 characterised by the choice of materials
• CPC Class Codes: B29K 2027/18 PTFE, i.e. polytetrafluorethene , e.g. ePTFE, i.e. expanded polytetrafluorethene
• CPC Class Codes: B29K 2105/04 cellular or porous
• CPC Class Codes: B29K 2105/16 Fillers
• CPC Class Codes: B32B 1/08 Tubular products

Abstract

A carbon containing vascular graft formed of expanded polytetrafluoroethylene and activated carbon admixed with at least a portion of the expanded polytetrafluoroethylene. A bioactive substance may be incorporated in the carbon containing vascular graft.

Claims

1. A tubular vascular graft, comprising an activated carbon and expanded polytetrafluoroethylene lumenal layer and an expanded polytetrafluoroethylene layer concentrically joined and co-extruded with one another to form an integral activated carbon and expanded polytetrafluoroethylene tubular wall structure wherein the activated carbon and expanded polytetrafluoroethylene lumenal layer further including a bioactive substance loaded therein fluid flow communication with a lumenal surface of the tubular wall structure.

2. The vascular graft of claim 1 wherein said bioactive substance comprises at least one of anticoagulant, an anti-microbial agent, an anti-inflammatory, a growth factor, a smooth muscle inhibitor, an antithrombotic, an antiplatelet agent, and a non-steroidal anti-inflammatory drug.

3. The tubular vascular graft according to claim 1, wherein the activated carbon has an average particle size less than or equal to 150 microns.

4. The tubular vascular graft according to claim 1, wherein the activated carbon further comprises an admixture of activated carbon and graphite.

5. A carbon containing vascular graft comprising:

a first layer forming a lumenal surface of the carbon containing vascular graft and defining a flow passage therethrough, said first layer comprising an admixture of expanded polytetrafluoroethylene and activated carbon; and

a second layer surrounding said first layer wherein said second layer comprises one of expanded polytetrafluoroethylene or an admixture of expanded polytetrafluoroethylene and activated carbon, wherein the first and second layers are concentrically and integrally joined to one another by;

a) molding a preform billet having a solid inner cylindrical portion formed of an admixture of polytetrafluoroethylene and activated carbon and an outer cylindrical portion surrounding said solid inner cylindrical portion and formed of at least one of polytetrafluoroethylene or an admixture of polytetrafluoroethylene and activated carbon;

b) co-extruding the first and second layers within the preformed billet to form a carbon-containing tubular extrudate;

c) longitudinally expanding the carbon-containing tubular extrudate to form a microporous polytetrafluoroethylene microstructure matrix consisting of nodes interconnected by fibrils with the activated carbon dispersed within the microporous polytetrafluoroethylene microstructure matrix; and

d) sintering the longitudinally expanded carbon-containing tubular extrudate wherein at least one of said first and second layers further comprises at least one bioactive compound selected from the group consisting of anticoagulant, anti-microbial agent anti-inflammatory, growth factor, smooth muscle inhibitor, antithrombotic, antiplatelet agent, and non-steroidal anti-inflammatory.

6. The carbon containing vascular graft of claim 5 wherein the step of molding a preform billet further comprises the steps of:

a) providing a preform barrel which is divided into inner and outer hollow concentric cylindrical sections by a hollow cylindrical divider,

b) compounding a polytetrafluoroethylene-lubricant admixture;

c) pouring the compounded polytetrafluoroethylene-lubricant admixture into one of the inner and outer cylindrical sections of the preform barrel;

d) compounding a polytetrafluoroethylene-lubricant-activated carbon admixture to form a polymeric carbon compound;

e) pouring the polymeric carbon compound into a second one of the inner and outer cylindrical sections of the preform barrel;

f) pressing said preform barrel to compact the polymer compound and the polymeric carbon compound; and

g) removing said preform barrel.

7. The carbon lined vascular graft of claim 6 wherein the activated carbon is present at approximately 3% to 20% by weight of the polytetrafluoroethylene.

8. The carbon lined vascular graft of claim 6 wherein said carbon component is an activated charcoal powder.

9. The carbon containing vascular graft according to claim 5, wherein the activated carbon has an average particle size less than or equal to 150 microns.

10. The carbon containing vascular graft according to claim 5, wherein the activated carbon further comprises an admixture of activated carbon and graphite.

11. A carbon containing vascular graft comprising:

a first layer forming a lumenal surface of the carbon containing vascular graft and defining a flow passage therethrough, said first layer comprising an admixture of expanded polytetrafluoroethylene and activated carbon; and

a second layer surrounding said first layer wherein said second layer comprises one of expanded polytetrafluoroethylene or an admixture of expanded polytetrafluoroethylene and activated carbon, wherein the first and second layers are concentrically and integrally joined to one another by;

a) molding a preform billet having a solid inner cylindrical portion formed of an admixture of polytetrafluoroethylene and activated carbon and an outer cylindrical portion surrounding said solid inner cylindrical portion and formed of at least one of polytetrafluoroethylene or an admixture of polytetrafluoroethylene and activated carbon, said step of molding a preform billet comprising the steps of;

i. providing a preform barrel which is divided into inner and outer hollow concentric cylindrical sections by a hollow cylindrical divider;

ii. compounding a polytetrafluoroethylene-lubricant admixture;

iii. pouring the compounded polytetrafluoroethylene-lubricant admixture into one of the inner and outer cylindrical sections of the preform barrel;

iv. compounding a polytetrafluoroethylene-lubricant-activated carbon admixture to form a polymeric carbon compound;

v. pouring the polymeric carbon compound into a second one of the inner and outer cylindrical sections of the preform barrel;

vi. pressing said preform barrel to compact the polymer compound and the polymeric carbon compound; and

vii. removing said preform barrel;

b) co-extruding the first and second layers within the preformed billet to form a carbon-containing tubular extrudate;

c) longitudinally expanding the carbon-containing tubular extrudate to form a microporous polytetrafluoroethylene microstructure matrix consisting of nodes interconnected by fibrils with the activated carbon dispersed within the microporous polytetrafluoroethylene microstructure matrix;

d) sintering the longitudinally expanded carbon-containing tubular extrudate; and

e incorporating a bioactive substance into the activated carbon prior to admixing the polytetrafluoroethylene-activated carbon-lubricant admixture.

12. The carbon lined vascular graft of claim 11 wherein the bioactive substance comprises at least one of an anticoagulant, an anti-microbial agent, an anti-inflammatory, a growth factor, a smooth muscle inhibitor, an antithrombotic, an antiplatelet agent, and a non-steroidal anti-inflammatory drug.

13. A carbon containing vascular graft comprising:

a first layer forming a lumenal surface of the tubular member and defining a flow passage therethrough, said first layer comprising an admixture of expanded polytetrafluoroethylene and activated carbon; and

a second layer surrounding said first layer wherein said second layer comprises one of expanded polytetrafluoroethylene or an admixture of expanded polytetrafluoroethylene and activated carbon, wherein the first and second layers are concentrically and integrally joined to one another by;

a) molding a preform billet having an inner cylindrical portion formed of an admixture of polytetrafluoroethylene and activated carbon and an outer cylindrical portion surrounding the inner cylindrical portion and formed of at least one of polytetrafluoroethylene or an admixture of polytetrafluoroethylene and activated carbon;

b) co-extruding the first and second layers within the preformed billet to form a carbon-containing tubular extrudate;

c) longitudinally expanding the carbon-containing tubular extrudate to form a microporous polytetrafluoroethylene microstructure matrix consisting of nodes interconnected by fibrils with the activated carbon dispersed within the microporous polytetrafluoroethylene microstructure matrix; and

d) sintering the longitudinally expanded carbon-containing tubular extrudate.

14. The carbon containing vascular graft of claim 13 wherein the step of molding a preform billet further comprises the steps of:

a) providing a preform barrel which is divided into inner and outer hollow concentric cylindrical sections by a hollow cylindrical divider;

b) compounding a polytetrafluoroethylene-lubricant admixture;

c) pouring the compounded polytetrafluoroethylene-lubricant admixture into one of the inner and outer cylindrical sections of the preform barrel;

d) compounding a polytetrafluoroethylene-lubricant-activated carbon admixture to form a polymeric carbon compound;

e) pouring the polymeric carbon compound into a second one of the inner and outer cylindrical sections of the preform barrel;

f) pressing said preform barrel to compact the polymer compound and the polymeric carbon compound; and

g) removing said preform barrel.

15. The carbon lined vascular graft of claim 13 wherein the activated carbon is present at approximately 3% to 20% by weight of the polytetrafluoroethylene.

16. The carbon lined vascular graft of claim 13 wherein the activated carbon is an activated charcoal powder.