Expandable coil endoluminal prosthesis

Abstract

A coiled stent ( 196 ) has a coiled stent body with a main body portion ( 106 ) and end portions ( 108 ). The end portions may be substantially less stiff than the body portion to help prevent tissue trauma. A graft material ( 124 ) may be used to cover at least the main body portion to create a coiled stent graft ( 122 ) in which adjacent turns ( 128 ) have gaps defined therebetween to create a generally helical gap ( 130 ). The coiled stent may have side elements ( 10 ) separated by connector elements ( 112 ) and be placeable in a contracted, reduced diameter state and in a relaxed, expanded diameter state. The connector elements are preferably generally parallel to the stent axis when placed in the contracted, reduced-diameter state, typically tightly wrapped around a placement catheter ( 136 ).

What is claimed is:  
     
         1 . A coiled endoluminal prosthesis comprising: 
 a body comprising a coiled ribbon of material;    the body comprising a main body portion and first and second end portions, the main body portion comprising first and second edge elements separated by connector elements, at least substantially all of the elements between the first and second edge elements being said connector elements;    the main body portion having a maximum width and the end portions having a maximum width no greater than the maximum width of the main body portion;    said body movable between a reduced diameter state, extending along a body axis, and an expanded diameter state; and    all said connector elements being at an acute angle to the edge elements when in the expanded diameter state, said angle chosen so that all of said connector elements lie generally parallel to the body axis when in the reduced diameter state so to provide a smoother appearance when in the reduced diameter state.    
     
     
         2 . A coiled endoluminal prosthesis according to  claim 1  wherein the end portions are substantially less stiff than the main body portion.  
     
     
         3 . A coiled endoluminal prosthesis according to  claim 1  wherein said end portions each have an inwardly-tapering portion with a blunt tip.  
     
     
         4 . A coiled endoluminal prosthesis according to  claim 1  wherein the main body portion comprises first, second and third longitudinal sections each having a different radial stiffness.  
     
     
         5 . A coiled endoluminal prosthesis according to  claim 1  wherein the stiffness of the main body portion continuously varies along at least part of its length.  
     
     
         6 . The coiled endoluminal prosthesis according to  claim 1  further comprising an orientation-specific marker carried by the body so to aid proper rotary orientation and longitudinal placement of the prosthesis.  
     
     
         7 . The coiled endoluminal prosthesis according to  claim 1  wherein the end portions comprise generally U-shaped members, said generally U-shaped members being thinner and more flexible than the edge and connector elements of the main body portion.  
     
     
         8 . The coiled endoluminal prosthesis according to  claim 1  wherein the end portions have a longitudinally-extending length and a laterally-extending width, said length being greater than said width.