September 24th, 2012
‘Dramatic’ Increase in Bleeding Accompanies Addition of Oral Anticoagulant Therapy in ACS
The newer oral anticoagulants may help reduce ischemic events after an acute coronary syndrome (ACS), but only at the cost of a “dramatic” increase in bleeding complications, according to a new meta-analysis published in the Archives of Internal Medicine.
Hungarian researchers performed a systematic review and meta-analysis of seven trials in which 31,286 ACS patients were randomized to placebo or a new oral anticoagulant, either an anti-Xa or direct thrombin inhibitor. All patients also received antiplatelet therapy. Here are the odds ratios for bleeding events and important clinical endpoints with the newer agents:
- TIMI major bleeding events: OR 3.03 (2.20-4.16)
- Overall mortality: OR 0.90 (0.76-1.06)
- Composite ischemic events: OR 0.86 (0.79-0.94)
- Stent thrombosis (definite or probable): OR 0.73 (0.54-0.98)
“These results suggest that the unrestricted use of new-generation oral anticoagulant agents as an adjunct to dual antiplatelet therapy after an ACS cannot be recommended,” the authors concluded. However, they left open the possibility that the newer oral anticoagulants may be beneficial in the 6%-21% of ACS patients who require long-term anticoagulation for atrial fibrillation and other conditions.
In an accompanying comment, Adrian Hernandez writes that “the conclusions of the meta-analysis seem to be robust.” He points out that the large differences in the relative risk of bleeding and clinical events found in the meta-analysis translate into smaller differences in absolute risk. Nevertheless, he writes, “the benefit is largely canceled by the harm; therefore, the routine use of [novel oral anticoagulants] among patients with ACS is unwarranted.”