Use of new-generation oral anticoagulant agents in patients receiving antiplatelet therapy after an acute coronary syndrome: systematic review and meta-analysis of randomized controlled trials.

Background: Despite receipt of dual antiplatelet therapy, patients after an acute coronary syndrome (ACS) remain at significant risk for thrombotic events. The role of orally activated Xa antagonist (anti-Xa) and direct thrombin inhibitors is debated in this setting. Our study objective was to evaluate the efficacy and safety of new-generation oral anticoagulant agents compared with placebo in patients receiving antiplatelet therapy after an ACS.

Methods: Electronic databases were searched to identify prospective randomized placebo-controlled clinical trials that evaluated the effects of anti-Xa or direct thrombin inhibitors in patients receiving antiplatelet therapy after an ACS. Efficacy measures included stent thrombosis, overall mortality, and a composite end point of major ischemic events, while thrombolysis in myocardial infarction-defined major bleeding events were used as a safety end point. The net clinical benefit was calculated as the sum of composite ischemic events and major bleeding events.

Results: For the period January 1, 2000, through December 31, 2011, we identified 7 prospective randomized placebo-controlled clinical trials that met the study criteria, involving 31 286 patients. Based on the pooled results, the use of new-generation oral anticoagulant agents in patients receiving antiplatelet therapy after an ACS was associated with a dramatic increase in major bleeding events (odds ratio, 3.03; 95% CI, 2.20-4.16; P < .001). Significant but moderate reductions in the risk for stent thrombosis or composite ischemic events were observed, without a significant effect on overall mortality. For the net clinical benefit, treatment with new-generation oral anticoagulant agents provided no advantage over placebo (odds ratio, 0.98; 95% CI, 0.90-1.06; P = .57).

Conclusion: The use of anti-Xa or direct thrombin inhibitors is associated with a dramatic increase in major bleeding events, which might offset all ischemic benefits in patients receiving antiplatelet therapy after an ACS.