Recent alternative approaches of vascular drug-eluting stents

Vascular stent is tubular shaped medical device designed to treat occluded circulatory or digestive systems by opening the blocked vascular sites. Originally stents were made of bare metals, such as stainless steel and cobalt–chromium alloys, due to their inherent corrosion resistance and good mechanical properties. Damage of intimal layer during expansion of stent, however, have caused neointimal hyperplasia resulting in in-stent restenosis which is one of main complications of vascular stent treatment. Drug-eluting stents (DESs) were introduced to alleviate this restenosis by local delivery of anti-proliferative drugs to the implanted or inserted site. The DES systems have been developed over the years by making changes in its main component, namely, drug, polymeric coating layer and expandable scaffold. Nevertheless, late thrombosis caused by drugs themselves and polymeric coating layer still remains as a serious problem of DES systems. Numerous studies, therefore, consistently focus on more advanced DES systems to solve the current issues. In this mini review article, we cast an opinion on how to improve the potential of DES system by means of (i) summarizing the history of DES system developed so far and (ii) updating current advances for the future generation of DES system.