Stent covering formed of porous polytetraflouroethylene

Abstract

Non-expanded porous PTFE materials and products are disclosed. More particularly, grafts and stent-grafts incorporating the non-porous PTFE materials are described.

1 . An endoprosthesis device comprising: 
 an elongate radially expandable tubular stent having an interior surface and an exterior surface extending along a longitudinal stent axis; and    a stent cover on said interior surface, exterior surface or both, said stent cover being formed of a polytetrafluoroethylene having no node and fibril structure;    wherein said porous polytetrafluoroethylene is formed by the steps of:    providing an interpenetrating network of siloxane/polytetrafluoroethylene;    removing said siloxane from said interpenetrating network leaving a porous polytetrafluoroethylene structure without a node and fibril structure.    
     
     
         2 . The endoprosthesis device of  claim 1  wherein said stent cover is on said exterior surface and said interior surface of said stent.  
     
     
         3 . The endoprosthesis device of  claim 1  wherein said stent cover is expandable upon expansion of said stent.  
     
     
         4 . The endoprosthesis device of  claim 1  wherein said siloxane is chemically extracted from said siloxane/polytetrafluoroethylene interpenetrating network.  
     
     
         5 . The endoprosthesis device of  claim 4  wherein said siloxane is chemically extracted by a compound selected from the group consisting of toluene, heptane and chloroform.  
     
     
         6 . The endoprosthesis device of  claim 1  wherein said siloxane is removed from said siloxane/polytetrafluoroethylene interpenetrating network by heating said network to a temperature of at least about 300° C.  
     
     
         7 - 12  (canceled).  
     
     
         13 . An endoprosthesis device comprising: 
 an elongate radially expandable tubular stent having an interior surface and an exterior surface extending along a longitudinal stent axis; and    a stent cover on said interior surface, exterior surface or both, which is formed of a polytetrafluoroethylene having no node and fibril structure;    wherein said porous polytetrafluoroethylene comprises a porous structure—having voids intermeshed between pockets of PTFE without a node and fibril structure.    
     
     
         14  (canceled).  
     
     
         15 . The endoprosthesis device of  claim 13  wherein said stent cover is on said exterior surface and said interior surface of said stent.  
     
     
         16 . The endoprosthesis device of  claim 13  wherein said stent cover is expandable upon expansion of said stent.  
     
     
         17 . The endoprosthesis device of  claim 1  wherein said siloxane is polydimethylsiloxane.  
     
     
         18 . The method of claim  7  wherein said siloxane is polydimethylsiloxane.