Late thrombosis of drug-eluting stents: a meta-analysis of randomized clinical trials.

Purpose: Drug-eluting stents are commonly used for percutaneous coronary intervention. Despite excellent clinical efficacy, the association between drug-eluting stents and the risk for late thrombosis remains imprecisely defined.

Methods: We performed a meta-analysis on 14 contemporary clinical trials that randomized 6675 patients to drug-eluting stents (paclitaxel or sirolimus) compared with bare metal stents. Eight of these trials have reported more than a year of clinical follow-up.

Results: The incidence of very late thrombosis (>1 year after the index procedure) was 5.0 events per 1000 drug-eluting stent patients, with no events in bare metal stent patients (risk ratio [RR]=5.02, 95% confidence interval [CI], 1.29 to 19.52, P=.02). Among sirolimus trials, the incidence of very late thrombosis was 3.6 events per 1000 sirolimus stent patients, with no events in bare metal stent patients (RR=3.99, 95% CI, .45 to 35.62, P=.22). The median time of late sirolimus stent thrombosis was 15.5 months, whereas with bare metal stents it was 4 months. Among paclitaxel trials, the incidence of very late thrombosis was 5.9 events per 1000 paclitaxel stent patients, with no events in bare metal stent patients (RR=5.72, 95% CI, 1.08 to 32.45, P=.049). The median time of late paclitaxel stent thrombosis was 18 months, whereas it was 3.5 months in bare metal stent patients.

Conclusions: Although the incidence of very late stent thrombosis more than 1 year after coronary revascularization is low, drug-eluting stents appear to increase the risk for late thrombosis. Although more of this risk was seen with paclitaxel stents, it remains possible that sirolimus stents similarly increase the risk for late thrombosis compared with bare metal stents.