The use of orally activated Xa antagonist (anti-Xa) and direct thrombin inhibitors is associated with a significant increase in major bleeding events in acute coronary syndrome (ACS) patients, a study shows.
The increased bleeding rate may offset all ischemic benefits in patients receiving antiplatelet therapy after an acute coronary syndrome event, suggest András Komócsi, University of Pécs, Hungary) and team in the Archives of Internal Medicine.
Their meta-analysis of 31,286 patients who received antiplatelet therapy after an ACS event between 2000 and 2011 shows that those who were also given new-generation oral anticoagulant agents, including anti-Xa or direct thrombin inhibitors, had a 3.03-fold increased risk for major bleeding events relative to those given placebo.
There were significant but moderate reductions in the risk for definite or probable stent thrombosis or for composite ischemic events with novel oral anticoagulant agents, at pooled odds ratios of 0.73 and 0.86, without a significant effect on overall mortality.
The authors note that for the net clinical benefit, which was calculated as the sum of composite ischemic events and major bleeding events, treatment with new-generation oral anticoagulant agents provided no advantage over placebo.
"Because subgroup analyses revealed no meaningful interaction for the evaluated outcomes, the results herein refute the unrestricted use of new-generation oral anticoagulant agents in combination with antiplatelet therapy among patients after an ACS," they write.
In a related commentary, editorialist Adrian Hernandez (Cleveland Clinic, Ohio, USA) asks whether novel oral anticoagulants may be useful for specific populations of patients with ACS. "Trials included in the meta-analysis were not performed among patients with specific types of ACS; therefore, it is unknown whether the effects of novel oral anticoagulants differ among patients with unstable angina, ST-elevation MI [myocardial infarction], and non-ST-elevation MI," he says.
"Trials are needed to evaluate the use of novel oral anticoagulants in these specific populations with ACS," he concludes.
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