Elastic characteristics of the self-expanding metallic stents

We measured elastic properties of the self-expanding metallic (Gianturco) stent using Hooke's law to characterize the stent with respect to its caliber, length, and radius by a coefficient of stiffness. Although this coefficient was independent of the radius of the stent, we found that it was directly dependent on caliber. For a stent of a particular caliber and length, the fractional change in radius determined the force exerted by the stent. For small radial displacements of the stent, the force required to compress it was directly proportional to the radial displacements; for large displacements, the force depended on a power series of the fractional radial displacement. A hyperbolic function was empirically introduced to approximate this type of relationship between force and radial displacement. We calculated tension and pressure exerted by the stent and suggest the use of our findings with normal vessels.