Cobalt chromium-based biodegradable polymer sirolimus-eluting stent: rationale, evidence and clinical experience.

Metallic drug-eluting stents (DES) are the first choice for percutaneous coronary interventional treatment of coronary artery disease at present. Although they have overcome some disadvantages and limitations of plain balloon angioplasty and bare-metal stents, chronic local inflammatory reactions related to permanent polymer existence and poor vascular healing after first generation DES implantation may translate into the increased risk of late and very late stent thrombosis. There have been technological developments in stent design, materials and coatings, including more conformable platform designs, biocompatible or biodegradable polymers and improved kinetics of drug release. The newer generation DES have proven superior to previous DES technology in terms of both safety and efficacy. Accumulating evidence has suggested that DES with cobalt chromium stent platform, modified biodegradable polymer coatings, and rapamycin derivative drugs are associated with improved clinical outcomes. Currently, several new cobalt chromium biodegradable polymer sirolimus-eluting stents have been introduced to clinical practice. This review will describe basic concept and rationale behind the newer cobalt chromium biodegradable polymer sirolimus-eluting stents, systematically present the new clinical experiences with several representative devices.