Pleated composite ePTFE/textile hybrid covering

1. A composite multilayer implantable material comprising:

a first inner tubular layer formed of expanded polytetrafluoroethylene having a porous microstructure defined by nodes interconnected by fibrils, wherein said first layer has a plurality of pleated folds, each of said pleated folds forming a masked portion under said pleated folds;

a second tubular layer formed of textile material circumferentially disposed exteriorly to said first layer, wherein said first and second layers are secured to each other by an elastomeric bonding agent positioned along a contacting layer of said first and second layers; and

wherein said masked portion of each of said pleated folds is not secured to said second layer by said bonding agent to permit unfolding and longitudinal lengthening of said composite multilayer implantable material.

2. The implantable material of claim 1 wherein said bonding agent is applied to one surface of said first layer.

3. The implantable material of claim 1 wherein said bonding agent is selected from the group consisting of urethanes, styrene/isobutylene/styrene block copolymers, silicones and combinations thereof.

4. The implantable material of claim 1 wherein said second layer comprises a textile pattern selected from the group comprising knits, weaves, stretch-knits, braids, any non-woven process, and combinations thereof.

5. The implantable material of claim 1 wherein said implantable material includes said first layer being a blood contact layer and said second layer being a tissue contacting layer.

6. The implantable material of claim 1 wherein said first, and second tubular layers form an elongate tubular vascular graft.

7. The implantable material of claim 6 wherein said graft includes a plurality of longitudinally spaced crimps therealong.

8. The implantable material of claim 6 wherein said graft is helically wrapped with a monofilament externally therearound.

9. The implantable material of claim 8 wherein said monofilament comprises polypropylene.

10. The implantable material of claim 9 wherein said monofilament is attached by heat bonding.

11. The implantable material of claim 8 wherein said graft includes an external support coil helically positioned thereover.

12. The implantable material of claim 1 wherein said elastomeric bonding agent is applied, to said second layer in solution.

13. The implantable material of claim 12 wherein said solution includes dimethylacetamide.

14. The implantable material of claim 1 , wherein the pleats are of uniform length.

15. The implantable material of claim 1 , wherein the pleats have uniform spacing.

16. A composite multilayer implantable structure comprising:

a first inner tubular layer formed of expanded polytetrafluoroethylene having a porous microstructure defined by nodes interconnected by fibrils;

a second tubular layer of expanded polytetrafluoroethylene circumferentially disposed exteriorly to said first layer, wherein said first and second layers have a plurality of pleated folds, each of said pleated folds being provided by doubling a continuous portion of said first layer and said second layer upon itself and pressing said continuous portion into an adjacent portion to define a masked portion under each of said pleated folds;

a support structure positioned between said first and said second layers;

a third tubular layer formed of textile material circumferentially disposed exteriorly to said second layer; and

an elastomeric bonding agent applied to one of said second layer or said third layer for securing said second layer to said third layer, wherein said masked portion is not secured to said third tubular layer by said bonding agent to permit unfolding and longitudinal lengthening of said composite multilayer implantable structure.

17. A composite structure of claim 16 wherein said bonding agent is applied to one surface of said first layer.

18. A composite structure of claim 16 wherein said bonding agent is applied to a surface of said third textile layer.

19. A composite structure of claim 16 wherein said bonding agent is selected from the group consisting of urethanes, styrene/isobutylene/styrene block copolymers, silicones and combinations thereof.

20. A composite structure of claim 16 wherein said third layer comprises a textile pattern selected from the group comprising knits, weaves, stretch-knits, braids, any non-woven process, and combinations thereof.

21. A composite structure of claim 16 wherein said third layer is placed in contact with a surface of said second layer.

22. A composite structure of claim 16 wherein said implantable structure includes said first layer being a blood contact layer and said third layer being a tissue contacting layer.

23. A composite structure of claim 16 wherein said first, second and third tubular layers form an elongate tubular vascular graft.

24. A composite structure of claim 23 wherein said graft includes a plurality of longitudinally spaced crimps therealong.

25. A composite structure of claim 23 wherein said graft is helically wrapped with a monofilament externally therearound.

26. A composite structure of claim 25 wherein said graft includes an external support coil helically positioned thereover.

27. A composite structure of claim 23 wherein said monofilament comprises polypropylene.

28. A composite structure of claim 27 wherein said monofilament is attached by heat bonding.

29. A composite structure of claim 16 wherein said elastomeric bonding agent is applied to said second layer in solution.

30. A composite structure of claim 29 wherein said solution includes dimethylacetamide.

31. The implantable material of claim 16 , wherein the pleated folds are of uniform length.

32. The implantable material of claim 16 , wherein the pleated folds have uniform spacing.