The conundrum of late and very late stent thrombosis following drug-eluting stent implantation

Purpose of review Drug-eluting stents reduce restenosis compared with bare metal stents, but there is growing concern that drug-eluting stents may lead to higher rates of late stent thrombosis, a rare and potentially catastrophic complication following stenting. Recent findings While the data on the risk of late stent thrombosis are not definitive, several general conclusions may be drawn from the available data. Late thrombosis, while associated with high mortality and morbidity, is an uncommon complication of both drug-eluting stents and bare metal stents. Randomized trials of approved drug-eluting stents versus bare metal stents have shown additional cases of late stent thrombosis in drug-eluting stents, but no significant difference in the cumulative incidence of stent thrombosis, myocardial infarction, or cardiac death at 4 years of follow-up. Observational studies suggest higher very late stent thrombosis incidence, but the relative risks of drug-eluting stents versus bare metal stents in specific high-risk groups require further study. Although the etiology of late stent thrombosis is multifactorial, premature discontinuation of clopidogrel appears to be the most important risk factor. Summary Long-term follow-up of patients after coronary stenting has identified stent thrombosis as a rare but serious event. Ongoing clinical trials in broader patient populations will be helpful to understand the risk of late stent thrombosis with greater certainty.