In-stent restenosis in the drug-eluting stent era

For the last two decades, restenosis has been considered the most significant problem in interventional cardiology. Drug-eluting stents (DES) have reduced rates of restenosis and target lesion revascularization (TLR) by 50–90% compared with bare-metal stents (BMS) across all lesion and patient subsets. However, a small number of patients have in-stent restenosis (ISR) after DES treatment. DES efficacy has been limited by suboptimal polymer biocompatibility, suitability of pharmacological agents, suboptimal in vivo pharmacokinetic properties, and local drug resistance and toxicity. The first two DES (sirolimus-eluting stents [SES] and paclitaxel- eluting stents [PES]) have the longest clinical follow- up, whereas the zotarolimus-eluting stents [ZES], everolimus-eluting stents [EES], and biolimus-eluting stents [BES] have only recently been introduced in daily practice. Although the low frequency of ISR events with DES makes it difficult to fully investigate this syndrome, many studies have been conducted or are ongoing to find the mechanism, incidence, predictors, and optimal treatment of DES restenosis. This review discusses the data relevant to DES restenosis and the perspective on the current treatment of this condition.