Dual antiplatelet therapy duration and clinical outcomes following treatment with zotarolimus-eluting stents

Objectives: We sought to evaluate differences in late safety outcomes relative to dual antiplatelet therapy (DAPT) duration in patients treated with zotarolimus-eluting stents (ZES). Background: Despite treatment recommendations for at least 12 months of DAPT following drug-eluting stent revascularization, device-specific outcomes relative to DAPT duration are absent. Methods: Among 2,032 patients undergoing percutaneous coronary revascularization with ZES in 5 trials, late safety events were compared relative to DAPT duration for patients with <6 months DAPT adherence and survival free of major ischemic and bleeding events. Results: A total of 1,414 event-free patients on DAPT at 6 months were identified. Patient group comparisons relative to DAPT included: 6 months versus <12 months, and 6 months versus ≥24 months. Through 3 years, risk-adjusted ischemic event rates did not significantly differ between groups: 6 versus ≥12 months: death (2.7% vs. 2.2%), myocardial infarction (MI, 0.3% vs. 1.1%), and definite/probable stent thrombosis (ST, 0.3% vs. 0%); 6 versus ≥24 months: death (1.6% vs. 1.6%), MI (0.4% vs. 1.2%), and definite/probable ST (0.1% vs. 0.2%). Composite events also did not statistically vary between DAPT durations. In multivariable analysis, 6-month versus longer DAPT duration was not associated with increased likelihood of thrombotic events at 3-year follow-up. Major bleeding was negligible across groups. Conclusions: Among patients treated with ZES, late-term events of death, MI, stroke, and ST do not significantly differ between patients taking 6 months DAPT compared with continuation beyond 1 year. These findings merit further study to identify the appropriate duration of DAPT according to specific drug-eluting stents.