Stent-graft with improved flexibility

Abstract

A flexible stent-graft has polymeric, non-textile graft layers with a stent disposed between or among the graft layers while allowing for movement of the stent between or among the layers. The stent includes an undulating wire stent disposed within pockets of non-secured graft portions between graft layers. The stent may be a ribbon stent having a ribbon or ribbons of graft layers.

1 . An endovascular stent-graft comprising:
 a tubular stent wall having opposed first and second ends;   an undulating wire having a thickness and having opposed first and second ends and being helically wound into a plurality of approximate circumferential windings to define the stent wall;   the undulating wire having a plurality of undulations defined by peaks and valleys with peaks of adjacent approximate circumferential windings being separated by a distance;   the first wire end secured to a first undulation at the first end;   the second wire end secured to a second undulation at the second end;   a graft liner comprising a layer of non-textile, polymeric graft material; and   a graft cover comprising a layer of non-textile, polymeric graft material;   wherein the graft liner and the graft cover are selectively secured to each other defining secured graft portions thereat and defining non-secured graft portions therein between, the non-secured graft portions defining a graft cavity between the graft liner and the graft cover;   wherein the tubular stent wall is disposed within the graft cavity; and   wherein the graft cavity has a longitudinal extent greater than the thickness of the undulating wire.   
     
     
         2 . The endovascular stent-graft of  claim 1 , wherein the secured graft portions have a longitudinal extent of about the thickness of the undulating wire or greater. 
     
     
         3 . The endovascular stent-graft of  claim 1 , wherein the secured graft portions have a longitudinal extent of about the thickness of the undulating wire or less. 
     
     
         4 . The endovascular stent-graft of  claim 1 , wherein, except for the first and the second wire ends being secured to the first and second undulations, respectively, adjacent approximate circumferential windings are free of interconnecting struts and welds. 
     
     
         5 . The endovascular stent-graft of  claim 1 , wherein the layer of non-textile, polymeric graft material for the graft cover comprises polytetrafluoroethylene selected from the group consisting of porous polytetrafluoroethylene having no discernible node and fibril microstructure, expanded polytetrafluoroethylene having a node and fibril microstructure, polytetrafluoroethylene having low or substantially no fluid permeability which includes a closed cell microstructure having high density regions having grain boundaries directly interconnected to grain boundaries of adjacent high density regions and having substantially no node and fibril microstructure, porous polytetrafluoroethylene having no or substantially no fluid permeability; semi-permeable polytetrafluoroethylene, permeable polytetrafluoroethylene, and combinations thereof. 
     
     
         6 . The endovascular stent-graft of  claim 1 , wherein the layer of non-textile, polymeric graft material for the graft liner comprises polytetrafluoroethylene selected from the group consisting of porous polytetrafluoroethylene having no discernible node and fibril microstructure, expanded polytetrafluoroethylene having a node and fibril microstructure, polytetrafluoroethylene having low or substantially no fluid permeability which includes a closed cell microstructure having high density regions having grain boundaries directly interconnected to grain boundaries of adjacent high density regions and having substantially no node and fibril microstructure, porous polytetrafluoroethylene having no or substantially no fluid permeability; semi-permeable polytetrafluoroethylene, permeable polytetrafluoroethylene, and combinations thereof. 
     
     
         7 . The endovascular stent-graft of  claim 1 , wherein the graft liner and the graft cover laminated or adhesively bonded each other at the secured graft portions. 
     
     
         8 . The endovascular stent-graft of  claim 1 , wherein the undulating wire is not secured to the graft liner and graft cover within the graft pocket. 
     
     
         9 . An endovascular stent-graft comprising:
 a tubular stent wall having opposed first and second ends;   an undulating wire having a thickness and having opposed first and second ends and being helically wound into a plurality of approximate circumferential windings to define the stent wall;   the undulating wire having a plurality undulations defined by peaks and valleys with peaks of adjacent approximate circumferential windings being separated by a distance;   the first wire end secured to a first undulation at the first end;   the second wire end secured to a second undulation at the second end;   a graft liner having opposed first and second end portions and a medial portion therein between, the graft liner comprising a layer of non-textile, polymeric graft material; and   a graft cover having opposed first and second end portions and a medial portion therein between, the graft liner comprising a layer of non-textile, polymeric graft material;   wherein the first end portion of the graft liner and the first end portion of the graft cover are secured to each other to define a fused first end;   wherein the second end portion of the graft liner and the second end portion of the graft cover are secured to each other to define a fused second end;   wherein at least one portion of the medial portions of the graft cover and the graft liner are not secured to each other defining a non-secured graft portion thereat, the non-secured graft portion defining a graft cavity between the graft liner and the graft cover; and   wherein the tubular stent wall is disposed within the graft cavity.   
     
     
         10 . The endovascular stent-graft of  claim 9 , further comprising a plurality of non-secured graft portions. 
     
     
         11 . The endovascular stent-graft of  claim 9 , wherein the non-secured graft portion extends substantially along the medial portions of the graft cover and graft liner. 
     
     
         12 . The endovascular stent-graft of  claim 9 , wherein the graft cover between the first and second ends comprises a pleated portion. 
     
     
         13 . The endovascular stent-graft of  claim 9 , wherein the graft cover between the first and second ends comprises a crimped portion. 
     
     
         14 . The endovascular stent-graft of  claim 9 , wherein, except for the first and the second wire ends being secured to the first and second undulations, respectively, adjacent approximate circumferential windings are free of interconnecting struts and welds. 
     
     
         15 . The endovascular stent-graft of  claim 9 , wherein the layer of non-textile, polymeric graft material for the graft cover comprises polytetrafluoroethylene selected from the group consisting of porous polytetrafluoroethylene having no discernible node and fibril microstructure, expanded polytetrafluoroethylene having a node and fibril microstructure, polytetrafluoroethylene having low or substantially no fluid permeability which includes a closed cell microstructure having high density regions having grain boundaries directly interconnected to grain boundaries of adjacent high density regions and having substantially no node and fibril microstructure, porous polytetrafluoroethylene having no or substantially no fluid permeability; semi-permeable polytetrafluoroethylene, permeable polytetrafluoroethylene, and combinations thereof. 
     
     
         16 . The endovascular stent-graft of  claim 9 , wherein the layer of non-textile, polymeric graft material for the graft liner comprises polytetrafluoroethylene selected from the group consisting of porous polytetrafluoroethylene having no discernible node and fibril microstructure, expanded polytetrafluoroethylene having a node and fibril microstructure, polytetrafluoroethylene having low or substantially no fluid permeability which includes a closed cell microstructure having high density regions having grain boundaries directly interconnected to grain boundaries of adjacent high density regions and having substantially no node and fibril microstructure, porous polytetrafluoroethylene having no or substantially no fluid permeability; semi-permeable polytetrafluoroethylene, permeable polytetrafluoroethylene, and combinations thereof. 
     
     
         17 . The endovascular stent-graft of  claim 9 , wherein the graft liner and the graft cover are laminated or adhesively bonded each other at the secured graft portions. 
     
     
         18 . An endovascular stent-graft comprising a ribbon stent-graft; the ribbon stent-graft comprising:
 a tubular stent wall having opposed first and second ends;   an undulating wire having a thickness and having opposed first and second ends and being helically wound into a plurality of approximate circumferential windings to define the stent wall;   the undulating wire having a plurality undulations defined by peaks and valleys with medial wire portions coextensive with the peaks and valleys, wherein the peaks of adjacent approximate circumferential windings are separated by a distance;   the first wire end secured to a first undulation at the first end;   the second wire end secured to a second undulation at the second end;   an elongate planar ribbon liner having opposed first and second end portions and a medial portion therein between, the planar ribbon liner comprising a layer of non-textile, polymeric graft material; and   an elongate planar ribbon cover having opposed first and second end portions and a medial portion therein between, the planar ribbon liner comprising a layer of non-textile, polymeric graft material;   wherein the elongate ribbon cover is disposed over the medial wire portions;   wherein the elongate ribbon liner is disposed under the medial wire portions; and   wherein the elongate ribbon cover and the elongate ribbon liner are securably disposed to each other and to the medial wire portions.   
     
     
         19 .- 30 . (canceled) 
     
     
         31 . The endovascular stent-graft of  claim 1 , wherein the endovascular stent-graft is configured to bend about 180° with about a 6 mm gap or less between portions of the graft cover proximal the bend; and wherein the endovascular stent-graft maintains a substantially tubular shape through the bend. 
     
     
         32 . The endovascular stent-graft of  claim 9 , wherein the endovascular stent-graft is configured to bend about 180° with about a 6 mm gap or less between portions of the graft cover proximal the bend; and wherein the endovascular stent-graft maintains a substantially tubular shape through the bend. 
     
     
         33 . (canceled) 
     
     
         34 . The endovascular stent-graft of  claim 1 , wherein the endovascular stent-graft is configured to bend about 180° or greater without the endovascular stent-graft having a substantial reduction in diameter in a portion of the bend. 
     
     
         35 . The endovascular stent-graft of  claim 9 , wherein the endovascular stent-graft is configured to bend about 180° or greater without the endovascular stent-graft having a substantial reduction in diameter in a portion of the bend. 
     
     
         36 . (canceled) 
     
     
         37 . The endovascular stent-graft of  claim 1 , wherein the secured graft portions lack sutures. 
     
     
         38 . The endovascular stent-graft of  claim 9 , wherein secured graft portions of the graft liner and the graft cover lack sutures. 
     
     
         39 . (canceled)