Flexible and conformable stent and method of forming same

An expandable stent is fabricated from a plurality of radially undulating rings, each pair of adjacent radially expandable undulating rings being interconnected by a multiplicity of flex members. Each flex member contacts a portion of an apex on one ring at a circumferential location and a portion of an apex of a directly adjacent ring at a circumferentially offset location. Each flex member is expandable and in one embodiment is circumferentially S-shaped. Adjacent flex members are mirror images of each other. The resulting stent is both flexible and strong when expanded thereby providing good scaffolding. In one embodiment, the strut material is fabricated of shape memory alloy such that when the strut is compressed so as to be insertable into a vessel, the strut will automatically expand to its previous dimension upon rising to the temperature of the vessel in which it is placed, thereby to expand and hold open the vessel without need for a balloon catheter.