Abstract: A stent for use in a lumen in a human or animal body, has a generally tubular body formed from a shape memory alloy which has been treated so that it exhibits enhanced elastic properties with a point of inflection in the stress-strain curve on loading, enabling the body to be deformed inwardly to a transversely compressed configuration for insertion into the lumen and then revert towards its initial configuration, into contact with and to support the lumen. The shape memory alloy comprises nickel, titanium and from about 3 at. % to about 20 at. %, based on the weight of the total weight of the alloy composition, of a ternary element selected from the group consisting of niobium, hafnium, tantalum, tungsten and gold. The ratio of the stress on loading to the stress on unloading at the respective inflection points on the loading and unloading curves is at least about 2.5:1, and the difference between the stresses on loading and unloading at the inflection points at least about 250 MPa.

Abstract: In accordance with the present invention, there is provided a stent, preferably a self-expanding Nitinol stent, for insertion into a vessel of a patient. The stent is made from a tubular member a thickness, front and back open ends, and a longitudinal axis extending therebetween. The member has a first smaller diameter for insertion into a vessel, and a second larger diameter for deployment into a vessel. The tubular member has a plurality of adjacent hoops extending between its front and back ends. The hoops are formed of a plurality of longitudinal struts, each having opposing ends and a center therebetween. The ends of the struts are shaped to form a plurality of loops which connect adjacent struts at the ends of the struts. The member further includes a plurality of bridges connecting adjacent hoops to one another. Each of the struts has a width which is greater at its ends than at its center. Preferably, the width continuously tapers from a greater width at the ends to a smaller width at the centers.

Abstract: A balloon expandable metal stent is provided that includes a multiplicity of circumferential sets of strut members wherein at least two adjacent circumferential sets of strut members are coupled together by a plurality of undulating longitudinal struts. The stent is annealed to a degree where frictional forces existing in the longitudinal direction between adjacent circumferential sets of strut members and the balloon, during inflation, are greater than a force required to permanently deform the undulating longitudinal struts. Thus, the expansion of the space between adjacent circumferential sets of strut members during inflation of the balloon compensates for shortening of the stent that would otherwise occur during radial expansion of the stent responsive to the inflation of the balloon.