Long-Term Clinical Outcomes Compare Zotarolimus-Eluting and Bare-Metal Stents

December 20, 2010—In a study that sought to evaluate the long-term safety of a zotarolimus-eluting stent (ZES) (Endeavor [Medtronic, Inc., Minneapolis, MN]) using a pooled analysis of pivotal trials, investigators concluded that over 5 years there was no increased risk of death, myocardial infarction, or stent thrombosis, and there was a benefit of prevention of repeat revascularization procedures in ZES compared with bare-metal stents (BMS).

Laura Mauri, MD, et al published the findings in the Journal of the American College of Cardiology: Cardiovascular Interventions (2010;3:1240–1249). The study was conducted because drug-eluting stents compared with BMS have reduced restenosis, but individual trials of these stents have not had sufficient power to ascertain long-term safety. Data was pooled from trials including ENDEAVOR PK (pharmacokinetic), ENDEAVOR II, ENDEAVOR III, and ENDEAVOR IV.

In the study, the investigators combined patient-level data from six prospective randomized single-arm multicenter trials involving 2,132 patients treated with ZES and 596 patients treated with a BMS control. The median follow-up was 4.1 years, with 5-year follow-up completed in 1,256 patients (97% of those eligible). The recommended minimum duration of dual-antiplatelet therapy in these studies was 3 to 6 months regardless of stent type. An independent events committee adjudicated all events. The two treatment groups were compared after adjustment for between-trial variation and for individual patient clinical and angiographic characteristics by propensity score.

The investigators reported that the cumulative incidence of adverse events at 5 years for ZES and BMS were: death, 5.9% versus 7.6% (adjusted hazard ratio [HR], 0.81; P = .34); cardiac death, 2.4% versus 3.7% (HR, 0.83; P = .57); myocardial infarction, 3.4% versus 4.8% (HR, 0.77; P = .37); target lesion revascularization, 7% versus 16.5% (HR, 0.42; P < .001); stent thrombosis (definite or probable), 0.8% versus 1.7% (HR, 0.5; P = .21). After adjustment for variation in study and patient characteristics, there were no significant differences in stent thrombosis or the clinical safety event rates at 5 years between ZES and BMS.