Flexible stent-graft device having patterned polymeric coverings
The present invention provides an endoprosthesis comprising a radially distensible, tubular stent comprising opposed open ends and a stent wall structure having opposed exterior and luminal surfaces; and a continuous and seamless ePTFE tubular covering having a node and fibril structure securably disposed to at least one of the stent surfaces, the graft covering comprising at least two laminated layers, wherein the laminated layers include at least one region where the laminated layers are not securely bonded; and the at least one region has a different bending flexibility from the tubular graft covering.
1. An endoprosthesis comprising:
a radially distensible, tubular stent comprising opposed open ends and a stent wall structure having opposed exterior and luminal surfaces; and
a seamless tubular covering secured to one of said stent surfaces and extending in a longitudinal direction, said seamless tubular covering comprising laminated PTFE having a node and fibril structure, wherein the laminated PTFE comprises at least two laminated layers wherein said laminated layers include at least one region where a first laminated layer has a plurality of dimples and the first laminated layer is not securely bonded to a second laminated layer, said at least one region having a different bending flexibility from regions where the first laminated layer is securely bonded to the second laminated layer.
2. An endoprosthesis according to claim 1 , wherein said tubular covering has a plurality of regions along the longitudinal direction of the tubular covering where the first laminated layer has a plurality of dimples.
3. An endoprosthesis according to claim 1 , wherein said plurality of dimples are arranged in at least one predetermined pattern.
4. An endoprosthesis according to claim 1 , wherein said plurality of dimples are arranged in more than one predetermined pattern.
5. An endoprosthesis according to claim 1 , wherein said stent further comprises a longitudinal length and said stent has an expanded state and a contracted state, wherein the longitudinal length of the stent in the expanded state is substantially equal to the longitudinal length of the stent in the contracted state.
6. An endoprosthesis according to claim 1 , wherein said stent is a self-expanding stent, a balloon-expandable stent or combinations thereof.
7. An endoprosthesis according to claim 1 , wherein said stent comprises a biocompatible material selected from the group consisting of metallic materials, polymeric materials, bioabsorbable materials, biodegradable materials, and combinations thereof.
8. An endoprosthesis according to claim 1 , wherein said stent comprises a plurality of undulating stent segments.
9. An endoprosthesis according to claim 1 , wherein said stent comprises an undulating wire helically wound into a plurality of circumferential adjacent windings to define said stent wall structure.
10. An endoprosthesis according to claim 1 , wherein said at least one region preferentially deforms when subjected to a bending stress as compared to other regions of said tubular covering.