Oral Anticoagulation versus Antiplatelet Treatment after Mitral Valve Repair: a Systematic Review and Meta-Analysis

Oral anticoagulation with vitamin K antagonists (VKA) is currently advised for a period of three months following surgical mitral valve repair, regardless of the rhythm status. The evidence supporting this recommendation is weak and recent studies have challenged the safety and efficacy of this recommendation. A systematic review of literature was conducted by searching PubMed, Embase, Web of Science, Emcare and Cochrane Library databases for original publications comparing the efficacy and safety of oral anticoagulation with vitamin K antagonists to antiplatelet treatment early after mitral valve surgery in patients with no atrial fibrillation. Study endpoints included thromboembolic complications, bleeding complications and survival. A total of five studies, including 5093 patients, met the inclusion criteria; 2824 patients were included in the oral anticoagulation and 2269 in the on antiplatelet treatment group. Pooled analyses demonstrated no beneficial effect of oral anticoagulation on the incidence of thromboembolic complications (risk ratio 1.14, 95% confidence interval 0.76–1.70, P=0.53, I2 = 8%). Moreover, oral anticoagulation did not result in a significantly increased risk of bleeding complications (risk ratio 0.89, 95% confidence interval 0.32 – 2.44, P=0.81, I2 = 87%). When combining the efficacy and safety endpoints, no difference was observed between groups (risk ratio 1.01, 95% confidence interval 0.51–1.97, P=0.99 I2 = 85%). Likewise, mortality did not differ between groups (risk ratio 0.89, 95% confidence interval 0.15–5.23, P=0.90 I2 = 71%). Our results confirmed the safety but failed to confirm the efficacy of oral anticoagulation in patients undergoing mitral valve surgery. A randomized controlled trial would provide the evidence needed to support treatment recommendations.