Composite ePTFE/textile prosthesis
View Patent ↗A composite intraluminal prosthesis which is preferably used as a vascular prosthesis includes a layer of ePTFE and a layer of textile material which are secured together by an elastomeric bonding agent. The ePTFE layer includes a porous microstructure defined by nodes interconnected by fibrils. The adhesive bonding agent is preferably applied in solution so that the bonding agent enters the pores of the microstructure of the ePTFE. This helps secure the textile layer to the ePTFE layer.
1. A composite multilayer implantable structure comprising:
a first inner tubular layer and second outer tubular layer formed of expanded polytetrafluoroethyene having a porous microstructure defined by nodes interconnected by fibrils, said first and second layers each seamless and substantially fluid-tight, said first and second layers each formed from a green fluoropolymer tube characterized by a generally uniform thickness being in the range of up to about 250 μm, said first and second layers having a support structure positioned there between, wherein said first layer is a blood contacting layer;
a third tubular layer formed of textile material circumferentially disposed exteriorly to said first and second layers, wherein said third tubular layer is a tissue contacting layer; and
an elastomeric bonding agent layer with a Shore Hardness of about 75 to 85A, said layer consisting essentially of a material selected from the group consisting of polycarbonate urethanes, styrene-isobutylene block copolymers, and combinations thereof, applied to cover one of said second layer or third layer and disposed within the pores of said microstructure to seal punctures, and for securing said second layer to said third layer;
wherein said first, second, and third tubular layers form an elongate vascular graft.
2. A composite structure of claim 1 wherein said bonding agent is applied to one surface of said second layer.
3. A composite structure of claim 2 wherein said third layer is placed in contact with said one surface of said second layer.
4. A composite structure of claim 1 wherein said bonding agent is applied to a surface of said third textile layer.
5. A composite structure of claim 1 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.
6. A composite structure of claim 1 wherein said support structure comprises a stent.
7. A composite structure of claim 1 wherein said graft includes a plurality of longitudinally spaced crimps therealong.
8. A composite structure of claim 1 wherein said graft is helically wrapped with a monofilament externally therearound.
9. A composite structure of claim 8 wherein said monofilament comprises polypropylene.
10. A composite structure of claim 9 wherein said monofilament is attached by heat bonding.
11. A composite structure of claim 8 wherein said graft includes an external support coil helically positioned thereover.
12. A composite structure of claim 1 wherein said elastomeric bonding agent is applied to said second layer in solution.
13. A composite structure of claim 12 wherein said solution includes dimethylacetamide.
14. A composite structure of claim 1 further comprising a fourth tubular layer formed of textile material circumferentially disposed interiorly to said first and second layers; and an elastomeric bonding agent applied to one of said first layer or said fourth layer and disposed within the pores of said microstructure for securing said first layer to said fourth layer.
15. A composite structure of claim 1 , wherein the first inner tubular layer and the second outer tubular layer are each a discrete tubular layer.