High On-Treatment Platelet Reactivity as a Risk Factor for Secondary Prevention After Coronary Stent Revascularization A Landmark Analysis of the ARCTIC Study

Background-Individualizing antiplatelet therapy after platelet function testing did not improve outcome after coronary stenting in the Assessment by a Double Randomization of a Conventional Antiplatelet Strategy Versus a Monitoring-Guided Strategy for Drug-Eluting Stent Implantation and of Treatment Interruption Versus Continuation One Year After Stenting (ARCTIC) study. Whether results are different during the phase of secondary prevention starting after hospital discharge, when periprocedural events have been excluded, is unknown. Methods and Results-In ARCTIC, 2440 patients were randomized before coronary stenting to a strategy of platelet function monitoring (VerifyNow P2Y(12) /aspirin point-of-care assay) with drug adjustment in suboptimal responders to antiplatelet therapy or to a conventional strategy without monitoring and without drug or dose changes. We performed a landmark analysis starting at the time of hospital discharge evaluating the primary end point of death, myocardial infarction, stent thrombosis, stroke, or urgent revascularization through 1 year. After discharge, the primary end point occurred in 8.6% of patients in the monitoring arm and 7.9% in the conventional arm (hazard ratio, 1.105; 95% confidence interval, 0.835-1.461; P=0.48). Stent thrombosis or urgent revascularization occurred in 4.4% and 4.5% in the monitoring and conventional arms, respectively (P=0.99). There was no difference for any of the other ischemic end points. Major bleeding event rates were 1.8% in the monitoring arm and 2.8% in the conventional arm (P=0.11), whereas major or minor bleeding event rates were 2.3% and 3.4%, respectively (P=0.10). Conclusions-Detection of platelet hyper-reactivity by platelet function testing in patients undergoing coronary stenting with further therapeutic adjustment does not reduce ischemic recurrences after intervention. On-treatment platelet hyperreactivity cannot be considered as a risk factor requiring intervention for secondary prevention after percutaneous coronary revascularization.