Late-Term Clinical Outcomes With Zotarolimus- and Sirolimus-Eluting Stents: 5-Year Follow-Up of the ENDEAVOR III (A Randomized Controlled Trial of the Medtronic Endeavor Drug [ABT-578] Eluting Coronary Stent System Versus the Cypher Sirolimus-Eluting Coronary Stent System in De Novo Native Coronary Artery Lesions)

Study Questions:

What are the late safety and efficacy outcomes following percutaneous coronary revascularization with zotarolimus-eluting stents (ZES) and sirolimus-eluting stents (SES)?

Methods:

Clinical outcomes were prospectively evaluated through 5 years in the ENDEAVOR III trial, which randomized 436 patients of relatively low anatomic and clinical risk to treatment with ZES (n = 323) or SES (n = 113) and evaluated a primary endpoint of 8-month angiographic late lumen loss. The Kaplan-Meier method was used to calculate the time to clinical endpoints, and the log-rank test was used to compare between-group differences.

Results:

At 5 years (completeness of follow-up: 95.2%), prespecified endpoints of all-cause mortality (5.2% vs. 13.0%, p = 0.02), myocardial infarction (1.0% vs. 4.6%, p = 0.03), and the composite event rates of cardiac death/myocardial infarction (1.3% vs. 6.5%, p = 0.009) and major adverse cardiac events (14.0% vs. 22.2%, p = 0.05) were significantly lower among patients treated with ZES. Rates of target lesion (8.1% ZES vs. 6.5% SES, p = 0.68) and target vessel revascularization were similar between treatment groups. Stent thrombosis was infrequent and similar in both groups (0.7% ZES vs. 0.9% SES, p = 1.0). Between 9 months and 5 years, progression of major adverse cardiac events was significantly more common with SES than with ZES (16.7% vs. 7.8%, p = 0.015).

Conclusions:

The authors concluded that despite initially higher angiographic late lumen loss, rates of clinical restenosis beyond the protocol-specified angiographic follow-up period remain stable with ZES compared with the rates for SES, resulting in similar late-term efficacy.

Perspective:

The study suggests that despite significantly higher 8-month angiographic late lumen loss, rates of clinical restenosis during later follow-up remain stable with ZES compared with SES, resulting in relatively small (1.5% absolute) overall differences in clinical restenosis rates at 5 years. Furthermore, restenosis risk was dissociated from clinical endpoints of death and myocardial infarction that favored treatment with ZES, contesting the notion that less favorable early angiographic surrogates of efficacy accurately predict important clinical events. The long-term clinical outcome results of this trial should be considered in the context of the other drug-eluting stent trials. At present, the everolimus-eluting stents appear very attractive and additional adequately powered head-to-head studies will be needed to truly discern superiority of one second-generation drug-eluting stent over another.

Clinical Topics: Invasive Cardiovascular Angiography and Intervention

Keywords: Myocardial Infarction, Follow-Up Studies, Thrombosis, Drug-Eluting Stents, Coronary Vessels, Sirolimus, Stents, Percutaneous Coronary Intervention


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