Collapsible, shape memory alloy structures and folding fixtures with associated method for collapsing same

Abstract

A shape memory alloy structure comprises at least one tubular member formed of shape memory material, each tubular member including a plurality of panels having side edges, wherein each tubular member is moveable between a radially contracted position and a radially extended position, and wherein the coupled side edges of adjacent panels of each tubular member form hinges for moving the structure between the contracted position and the extended position. Multiple layer tubular structures, methods for forming and fixtures for collapsing same are also disclosed.

1 . An A shape memory alloy structure extending along a longitudinal axis and having a radially retracted state and a deployed state, said structure comprising a tubular member including a plurality of substantially solid, concave outer surface panels forming a circumference of the tubular member, each panel coupled to two adjacent panels on opposed sides at peak portions at radially outermost portions of the tubular member in the deployed state, and wherein each panel extends substantially parallel to a longitudinal axis of the prosthesis, and wherein the radially retracted state has the panels and the peak portions of the tubular member positioned radially inwardly of their respective positions in the deployed state and the radially retracted state has each panel bending about an axis parallel to the longitudinal axis forming generally greater outer surface concavity than in the deployed state, whereby a substantially tight serpentine structure is formed by the panels and peaks in the retracted state. 
     
     
         2 . The shape memory alloy structure according to  claim 1  wherein the shape memory alloy is a nitinol structure and wherein the effective outer diameter of the structure in the radially retracted state is less than about 6 mm. 
     
     
         3 . A shape memory alloy structure comprising at least one tubular member formed of shape memory alloy and formed of a plurality of substantially solid scalloped panels separated by peaks, wherein the structure is moveable between a radially contracted position and a radially extended position, wherein the effective outer diameter of the structure in the radially extended position at least 3.5 times the effective outer diameter of the structure in the radially contracted position. 
     
     
         4 . The shape memory alloy structure according to  claim 3  wherein the effective outer diameter of the structure in the radially contracted position is less than about 6 mm. 
     
     
         5 . The shape memory alloy structure according to  claim 3  wherein the shape memory alloy is a nitinol structure. 
     
     
         6 . The shape memory alloy structure according to  claim 3  wherein the structure is a prosthetic cardiovascular stent. 
     
     
         7 - 14 . (canceled)