SELF-EXPANDABLE STENT AND STENT-GRAFT

The device is a foldable stent (122) or stent-graft (370) which may be delivered with (or on) a catheter or via surgical or other suitable techniques. The device is then expanded or unfolded. The expandable stent structure preferably utilizes at least one torsional member (100) generally aligned with the longitudinal axis of the stent (122). The stent (122) preferably has an undulating shape. It may be helically deployed to form the generally cylindrical shape eventually deployed as the stent (122) or it may be formed of one or more rings (302). The structure desirably is aligned to allow those undulating shapes in adjacent rings (322) or turns of the helix to be in phase. The adjacent undulating shapes may be held in that phased relationship using a flexible linkage often made of a polymeric material. The stent (122) is self-expanding, kink-resistant, easily bent along its longitudinal axis, does not change its length during that expansion, and is able to provide collapsible support for otherwise frangible graft material. The graft component (134) cooperating with the stent (122) is tubular and may be biocompatible polymeric or collagenous material or combinations of the two which may, if desired, be reinforced with fibers.