Process for fabricating a prosthesis

Abstract

A body implantable stent is formed of a plurality of strands arranged in two sets of coaxial helices, wound in opposite directions to form multiple crossings. At selected crossings, the adjacent strands are welded to one another, while at the remaining crossings the strands are free for limited movement relative to one another. The welds are formed in patterns that preferably enhance radial strength and rigidity, while having a minimal impact on axial bending flexibility. Preferred weld patterns in this regard include rings or circumferential rows, and helices, particularly with a steeper pitch than that of the strands. Stent fabrication preferably involves resistance welding at the crossings, and use of a tool to reuniformly compress the stent around and against the distal end region of a balloon catheter used later to deliver the stent to a treatment site.