Stent-graft having flexible geometries and methods of producing the same

An implantable prosthesis comprising:

• a tubular stent comprising a plurality of circumferential windings defining a stent wall, said stent wall having opposed exterior and luminal surfaces;
• and
• a non-textile polymeric tubular graft comprising a continuous tubular wall securably attached to at least one of said stent surfaces, said tubular wall having a luminal surface extending along the length of said tubular graft, said tubular graft having a node and fibril structure and consisting of first regions and second regions, said fibril structure at said first regions being more circumferentially oriented than said fibril structure at said second regions, said second regions each comprising three longitudinally side-by-side circumferential recesses, said circumferential recesses extending only part way through said tubular wall of said tubular graft, said luminal surface of said tubular graft being free of said recesses;
• said first regions being securably attached to said circumferential windings and said second regions being disposed between said circumferential windings, wherein said first regions are free of circumferential recesses and have a different bending flexibility than said second regions.

A method of making a stent-graft comprising:

• providing a radially distensible tubular stent having a plurality of adjacent windings, said tubular stent comprising opposed open ends and a stent wall structure having opposed exterior and luminal surfaces;
• providing a continuous ePTFE tubular graft extending between said opposed open ends of said stent, said ePTFE tubular graft having a node and fibril structure, said graft securably disposed to one of said stent surfaces, said graft comprising a continuous tubular wall having a luminal surface extending along the length of said tubular graft, said tubular wall consisting of first regions free of circumferential recesses and second regions, each second region comprising three longitudinally side-by-side circumferential recesses, wherein said circumferential recesses extend only part way through said tubular wall of said tubular graft, said luminal surface of said tubular wall being free of said recesses, said fibril structure at said first regions is more circumferentially oriented than said fibril structure at said second regions;
• securably attaching said windings to said first regions;
• positioning said second regions between adjacent windings;
• and
• providing said first regions with a different bending flexibility from said second regions.

A method of supporting a stent-graft previously deployed within a bodily lumen, comprising:

• providing:
• an endoprosthesis comprising a radially distensible, tubular stent having a plurality of adjacent windings, said tubular stent comprising opposed open ends and a stent wall structure having opposed external and luminal surfaces, and
• a continuous and seamless ePTFE tubular covering extending between said opposed open ends of said stent, said 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 having a luminal surface extending along the length of said tubular covering, said tubular wall consisting of first regions free of circumferential recesses and second regions, said fibril structure at said first regions is more circumferentially oriented than said fibril structure at said second regions, each second region comprising three longitudinally side-by-side circumferential recesses, said first regions having a different bending flexibility from said second regions, said circumferential recesses extend only part way through said tubular wall of said covering, said luminal surface of said tubular covering being free of said recesses, wherein said first regions are securably attached to said adjacent windings and said second regions are positioned between said adjacent windings;
• deploying the endoprosthesis within the previously deployed stent-graft;
• and
• expanding the endoprosthesis to support the previously deployed stent-graft.

A prosthesis comprising:

• a stent comprising an undulating wire wound into a plurality of circumferential windings defining opposed exterior and luminal surfaces of said stent;
• 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 the ends of said stent, said covering consisting of first regions and second regions, wherein said fibril structure at said first regions is more circumferentially oriented than said fibril structure at said second regions;
• said first regions being free of indentations, said first regions securably attached to said circumferential windings;
• said second regions of said ePTFE covering being disposed between adjacent windings of said circumferential windings of said undulating wire;
• wherein each of said second regions of said covering comprises three longitudinally side-by-side indentations, said indentations not extending all the way through said covering, said second regions having a greater bending flexibility than said first regions.

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 having a luminal surface extending along the length of said tubular covering, said tubular wall comprising a first region and second region, said fibril structure at said first regions is more circumferentially oriented than the fibril structure at said second regions, wherein said first region is securably attached to at least one of said circumferential windings of said undulating wire and is free of recesses which extend substantially along a circumferential axis;
• wherein said second region of said ePTFE covering is disposed between at least two adjacent windings of said circumferential windings of said undulating wire;
• and
• wherein said second region of said covering comprises three circumferential recesses and has a greater bending flexibility than said first region, said circumferential recesses extending only part way through said tubular wall of said tubular covering, said luminal surface of said tubular covering being free of any of said recesses.