Biodegradable and Bioabsorbable Stents

Angioplasty of the coronary arteries has made significant headway in the past 20 years as a treatment for atherosclerotic vascular disease. Though drug-eluting stents are effective, they appear to invoke a thrombogenic response. Biodegradable stents are a promising alternative to permanent stents and may eventually be used to solve the lingering problem of in-stent restenosis. Additionally, fully degradable stents have the ability to deliver more drugs to the target site than a thin coating of drug on metallic stents. A variety of degradable materials have been studied for stent design, including polyesters, polycarbonates, bacterial-derived polymers, and corrodible metals. The ideal biodegradable stent would be reliably deployable under fluoroscopic guidance and situate into the target lesion with minimal endovascular trauma. The stent should degrade into nontoxic byproducts and invoke a minimal degree of inflammation at the target site. Finally, the stent itself should disappear within months (to years) without significant displacement from the deployment site. Although initial data from clinical trials have been sufficient to bring biodegradable materials into the realm of feasibility, future research is undoubtedly necessary to resolve the critical issues of inflammation and mechanical stability.