Stent thrombosis in randomized clinical trials of drug-eluting stents.

Background: Definitions of stent thrombosis that have been used in clinical trials of drug-eluting stents have been restrictive and have not been used in a uniform manner.
Methods: We applied a hierarchical classification of stent thrombosis set by the Academic Research Consortium (ARC) across randomized trials involving 878 patients treated with sirolimus-eluting stents, 1400 treated with paclitaxel-eluting stents, and 2267 treated with bare-metal stents. We then pooled 4 years of follow-up data. All events were adjudicated by an independent clinical-events committee.
Results: The cumulative incidence of stent thrombosis according to the original protocol definitions was 1.2% in the sirolimus-stent group versus 0.6% in the bare-metal-stent group (P=0.20; 95% confidence interval [CI], -0.4 to 1.5) and 1.3% in the paclitaxel-stent group versus 0.8% in the bare-metal-stent group (P=0.24; 95% CI, -0.3 to 1.4). The incidence of definite or probable stent thrombosis as defined by the ARC was 1.5% in the sirolimus-stent group versus 1.7% in the bare-metal-stent group (P=0.70; 95% CI, -1.5 to 1.0) and 1.8% in the paclitaxel-stent group versus 1.4% in the bare-metal-stent group (P=0.52; 95% CI, -0.7 to 1.4). The incidence of definite or probable events occurring 1 to 4 years after implantation was 0.9% in the sirolimus-stent group versus 0.4% in the bare-metal-stent group and 0.9% in the paclitaxel-stent group versus 0.6% in the bare-metal-stent group.
Conclusions: The incidence of stent thrombosis did not differ significantly between patients with drug-eluting stents and those with bare-metal stents in randomized clinical trials, although the power to detect small differences in rates was limited.
(Copyright 2007 Massachusetts Medical Society.)