| 摘要 |
<p>A body compatible stent is formed of multiple filaments arranged in two sets of oppositely directed helical windings interwoven with one another in a braided configuration. Each of the filaments is a composite including a central core (24) and a case (26) surrounding the core (24). The core is formed of a radiopaque and relatively ductile material, in particular gold or a gold alloy. The outer case (26) is formed of a relatively resilient material, e.g. a cobalt/chromium based alloy. Favorable mechanical characteristics of the stent are determined by the case (26), while the core (24) enables in vivo imaging of the stent. The composite filaments are formed by a drawn filled tubing process in which the core (24) is inserted into a tubular case (26) of a diameter substantially more than the intended final filament diameter. The composite filament is cold-worked in several steps to reduce its diameter, and annealed between successive cold-working steps. After the final cold working step, the composite filament is formed into the desired shape and age hardened.</p> |
