Efficacy and safety of combined anticoagulant and antiplatelet therapy versus anticoagulant monotherapy after mechanical heart-valve replacement: a metaanalysis.

We performed a metaanalysis of five randomized controlled trials to compare the efficacy and safety of combined oral anticoagulant and antiplatelet therapy versus oral anticoagulants alone after prosthetic heart-valve replacement. The combined regimen reduced embolism and overall mortality by approximately 67% (pooled odds ratio [OR] 0.33; 95% confidence interval [CI] 0.16 to 0.69; p = 0.0032) and 40% (OR 0.60; 95% CI 0.32 to 1.12; p = 0.11), respectively, but increased the risk of hemorrhage by approximately 65% (OR 1.65; 95% CI 1.15 to 2.39; p = 0.0069) and of major gastrointestinal hemorrhage by approximately 250% (OR 3.47; 95% CI 1.43 to 8.40; p = 0.0058). It is estimated that for every 1.6 patients who had their stroke prevented by combination therapy, there was an excess of one major gastrointestinal bleed. This metaanalysis suggests that the benefits derived from the enhanced antithrombotic potential of combined therapy outweigh the toxic effects resulting from the enhanced anticoagulant potential of this regimen.