Background: Mechanical valves are durable and preferred in young adults requiring valve replacement surgery, but necessitates life-long anticoagulation. We reviewed studies comparing direct oral anticoagulants (DOACs) to vitamin K antagonists (VKA) in patients with mechanical aortic or mitral valves.
METHODS AND RESULTS: We searched MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials for randomized controlled trials (RCTs) from inception until March 4, 2024. Two reviewers independently screened studies, extracted data, and assessed the risk of bias. Outcomes of interest included major bleeding, valve thrombosis and valve-related systemic thromboembolism, and all-cause systemic thromboembolism. We performed fixed- and random-effects meta-analysis with relative risk (RRs) using DataParty (https://dataparty.ca, Hamilton, Ontario) and assessed the certainty of evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework. We included 3 RCTs (n=1159). Compared to VKAs, DOACs showed no significant difference in major bleeding (RR 0.82, 95% confidence interval [95%CI] 0.32–2.11, very-low certainty), but increased valve thrombosis and valve-related thromboembolism (RR 6.18, 95%CI 0.78–48.9, low certainty), and all-cause systemic thromboembolism (RR 2.44, 95%CI 1.24–4.83, moderate certainty).
Conclusion: In patients with mechanical aortic or mitral valves, DOACs may result in similar rates of major bleeding but increased valve thrombosis and valve-related thromboembolism, and systemic thromboembolism when compared with VKAs.
