Valve-Specific Comparative Effectiveness of Direct Oral Anticoagulants Versus Vitamin K Antagonists After Surgical Valve Procedures in Atrial Fibrillation: A Systematic Review and Meta-Analysis

Abstract: Anticoagulation after left-sided bioprosthetic valve replacement or mitral valve repair in patients with atrial fibrillation (AF) remains uncertain, as decisions must balance prevention of thromboembolism against bleeding risk in a heterogeneous postoperative population. Although vitamin K antagonists (VKAs) have long been the standard of care, expanding real-world use of direct oral anticoagulants (DOACs) has created an urgent need to define their comparative effectiveness and safety in this setting. We performed a systematic review and meta-analysis of randomized and observational studies comparing DOACs with VKAs in patients with AF after surgical left-sided bioprosthetic valve replacement or mitral valve repair. The primary outcome was ischemic stroke; secondary outcomes included composite thromboembolic events, major bleeding, and all-cause mortality. Pooled risk ratios were estimated using random-effects models, with prespecified subgroup and sensitivity analyses to explore clinical heterogeneity. Fourteen studies including 15,877 patients met inclusion criteria. Compared with VKAs, DOACs were associated with a lower observed risk of ischemic stroke, although this finding was largely driven by patients with aortic bioprosthetic valves. Across analyses, heterogeneity was moderate, and no significant differences were observed for composite thromboembolic events, major bleeding, or all-cause mortality. These findings suggest that DOACs may be a reasonable alternative to VKAs in selected patients with AF after surgical valve intervention. However, the dependence of treatment effect on valve type underscores that left-sided valve populations should not be treated as clinically interchangeable. Anticoagulation decisions should be individualized, integrating valve position, surgical substrate, thromboembolic risk, bleeding risk, and the strength of available evidence.