No Increased Risk Seen in Stopping DAPT at 6 Months After Stenting

October 21, 2011—In the Journal of the American College of Cardiology: Cardiovascular Interventions, David E. Kandzari, MD, et al published findings from a study that sought to evaluate differences in late safety outcomes relative to dual-antiplatelet therapy (DAPT) duration in patients treated with zotarolimus-eluting stents (2011;4:1119–1128). The background of the study is that despite treatment recommendations for at least 12 months of DAPT following drug-eluting stent revascularization, device-specific outcomes relative to DAPT duration are absent, the investigators stated.

As detailed in the Journal of the American College of Cardiology: Cardiovascular Interventions, the analysis was composed of 2,032 patients in five trials undergoing percutaneous coronary revascularization with zotarolimus-eluting stents. Late safety events were compared relative to DAPT duration for patients with 6 months of DAPT adherence and survival free of major ischemic and bleeding events.

The investigators reported that 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. Rates at 6 months versus 12 months were death in 2.7% versus 2.2%, myocardial infarction in 0.3% versus 1.1%, and definite/probable stent thrombosis in 0.3% versus 0%. Rates at 6 months versus 24 months were death in 1.6% versus 1.6%, myocardial infarction in 0.4% versus 1.2%, and definite/probable stent thrombosis in 0.1% versus 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 an increased likelihood of thrombotic events at 3-year follow-up. Major bleeding was negligible across groups, stated the investigators.

The investigators concluded that among patients who were treated with zotarolimus-eluting stents, late-term events of death, myocardial infarction, stroke, and stent thrombosis did not significantly differ between patients taking 6 months of DAPT compared with continuation beyond 1 year. They also stated that these findings merit further study to identify the appropriate duration of DAPT according to specific drug-eluting stents.