Aspirin plus warfarin compared to aspirin alone after acute coronary syndromes: an updated and comprehensive meta-analysis of 25 307 patients (original) (raw)

Aims In patients recovering from acute coronary syndromes (ACS) the role of oral anticoagulation (and its intensity) in addition to aspirin remains controversial. We conducted a specific meta-analysis of randomized trials comparing aspirin plus warfarin (AþW) with aspirin alone in such patients. Methods and results MEDLINE and Cochrane databases yielded 14 (of 148 potentially relevant) articles enrolling 25 307 patients. Follow-up ranged from 3 months to 5 years. Irrespective of International normalized ratio (INR), AþW did not significantly affect the risk of major adverse events (MAE: all cause death, non-fatal myocardial infarction, and non-fatal thrombo-embolic stroke) when compared with aspirin alone [OR 0.96 (0.90-1.03), P ¼ 0.30], but increased the risk of major bleeds (MB): OR 1.77 (1.47-2.13), P , 0.00001. However, in studies with INR of 2-3, AþW was associated with a significant reduction of MAE [OR 0.73 (0.63-0.84), P , 0.0001, number needed to treat to avoid one MAE ¼ 33], albeit at an increased risk of MB [OR 2.32 (1.63-3.29), P , 0.00001; number needed to harm by causing one MB ¼ 100]. In both analyses, intracranial bleeding was not significantly increased by AþW when compared with aspirin alone. Conclusion For patients recovering from ACS, a combined strategy of AþW at INR values of 2-3 doubles the risk of MB, but is nonetheless superior to aspirin alone in preventing MAE. Whether this combined regimen is also superior to a 'double' anti-platelet strategy or to newer evolving treatments warrants further investigation.