Duration of clopidogrel-based dual antiplatelet therapy and clinical outcomes after endeavor sprint zotarolimus-eluting stent implantation in patients presenting with acute coronary syndrome

Background The optimal duration of dual antiplatelet therapy (DAPT) remains controversial in patients with acute coronary syndrome (ACS). We sought to compare outcomes after the implantation of zotarolimus-eluting stent (ZES) between patients with ACS who received clopidogrel-based DAPT for > 6 months and those treated for ≤ 6 months. Methods From a registry of patients treated with ZESs between October 2005 and January 2010, 1740 patients with ACS were selected for the present analysis. Landmark analyses were performed for ACS patients who were event-free at 6 months follow-up (n = 1674). The primary outcome was a major adverse cardiac and cerebrovascular event (MACCE), including all-cause death, myocardial infarction (MI), target vessel revascularization (TVR), stent thrombosis, or stroke. We also performed adjustments for the baseline characteristics of patients, using their propensity-score matching (n = 469 pairs). Results During a median follow-up of 22.5 months, the rate of MACCE was 6.4% in patients with DAPT > 6 months (n = 1140) and 4.7% in patients with DAPT ≤ 6 months (n = 534) (adjusted hazard ratio [HR] 1.05; 95% confidence interval [CI] 0.61-1.82; p = 0.86). After propensity-score matching, DAPT > 6 months was not found to be associated with a lower incidence of MACCE compared with DAPT ≤ 6 months (adjusted HR 0.80, 95% CI 0.44-1.45, p = 0.46). The rates of all-cause death or MI, TVR, stent thrombosis, and stroke also did not differ significantly between two groups. Conclusion DAPT for > 6 months do not seem to be associated with improved clinical outcomes in patients with ACS undergoing percutaneous coronary intervention (PCI) with ZES.