Range of Thermal Treatment Upon the Mechanical Characteristics of PLLA Coiled Stents

Stents have been used as a medical device to restore blood flow in stenosed vessels. During this process of stent expansion, the balloon and stent could damage the endothelial lining of the vascular wall [Grewe, Farb] and alter the mechanical stress states of various tissue components. The subsequent tissue re-growth and vascular remodeling have been implicated among the causes leading to restenosis. Stent designs vary over a wide range from materials used, geometric shapes, fabrication methods, treatments, among many other parameters. There are many different stent designs. We have developed an internally coiled, furled helical PLLA fiber stent at our institution [Su 03, Zilberman 02, 04, 05]. We have previously shown the effect of 62°C thermal annealing on the expansive characteristics of this stent [Welch 08].