Patent ID: 8025693

Claim:
An endoprosthesis comprising: a radially distensible, tubular stent comprising opposed open ends, a stent wall structure having opposed exterior and luminal surfaces and an undulating wire helically wound into a plurality of circumferential adjacent windings to define said stent wall structure; and a continuous and seamless ePTFE tubular covering having a node and fibril structure securably disposed to at least one of said stent surfaces, said covering comprising a tubular wall extending between said opposed ends of said tubular stent, said tubular wall having a luminal surface that extends therealong, said tubular wall consisting of first regions and second regions, wherein said first regions are securably attached to said circumferential windings of said undulating wire and are free of circumferential recesses, said fibril structure at said first regions is more circumferentially oriented than said fibril structure at said second regions; wherein said second regions of said ePTFE covering are disposed between adjacent windings of said circumferential windings of said undulating wire; and wherein said second regions of said covering each comprise three longitudinally side-by-side circumferential recesses and have greater bending flexibility than said first regions, said circumferential recesses extending only part way through said tubular wall of said tubular covering and said luminal surface of said tubular covering being free of said recesses.