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

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.