Thermal Treatment Effects Upon the Degradation Characteristics of PLLA Coiled Stents

Stents are a medical device used to restore blood flow in stenosed vessels. During the process of stent expansion, the balloon and stent could damage the endothelial lining of the vascular wall and alter the mechanical stress states of various tissue components. The evolution of stents has progressed from bare metal stents to drug eluting stents or stents coated with drugs such as Sirolimus. Drug eluting stents are currently used to address the restenosis event that occurs after implantation. These stents have been effective but late stent thrombosis has been an emerging issue with drug eluting stents. Bioresorbable stents have emerged as a potential candidate for drug eluting stents. Su 03 has shown drug-loading PLLA with curcumin can be used as an anti-inflammatory agent. 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].