Biodegradable Polymers and Stents: the Next Generation?

Abstract

Stent design continues to evolve with newer generation of stents aimed at improving clinical outcomes. This review compares different generations of stents with a focus on biodegradable polymers and stents and their potential benefits. Drug-eluting stents (DES) reduce stent thrombosis when compared with bare-metal stents (BMS). However, they are associated with impaired vascular healing/endothelialization and excess very long-term events (beyond 1 year). Much of these events (beyond 1 year) have been attributed to continued inflammation due to the polymer. Biodegradable-polymer drug-eluting stents (BP DES) were designed to overcome this polymer related limitation of first-generation DP DES by combining the benefits of reduced in-stent restenosis seen with DES and the benefits of reduced very-late stent thrombosis and myocardial infarction due to absence of polymer with bare-metal stents (BMS). Earlier generation of BP DES showed superiority over first-generation DP DES but at best non-inferior to second-generation DP DES for clinical outcomes; however, the newer-generation BP DES with ultrathin struts show promise in further reducing clinical outcomes when compared with second-generation DP DES. Whether this is due to the biodegradable polymer or the ultrathin struts continues to be debated. Biodegradable polymer stents in conjunction with ultrathin struts have shown promise as the next generation of DES; however, additional studies and long-term follow-up are needed to confirm these effects.