Systematic Review and Meta-Analysis: Can We Compare Direct Oral Anticoagulants to Warfarin in Patients With Atrial Fibrillation and Bio-Prosthetic Valves?

Background There are no clear consensus guidelines on the indications and types of anticoagulation therapies in patients with bio-prosthetic valves either with concomitant atrial fibrillation (AF) or sinus rhythm. In our meta-analysis, we assessed the safety and efficacy of DOACs as compared to the standard treatment with warfarin in patients with AF and bioprosthetic valves. Methods We included randomized controlled trials (RCTs), cohort studies in the English language, and studies reporting patients with valvular heart disease that included bioprosthetic valvular disease. A systematic literature review using Embase, PubMed, and Web of Science was performed using the terms "Direct Acting Oral Anticoagulant," "Oral Anticoagulants," "Non-Vitamin K Antagonist Oral Anticoagulant," "Atrial Fibrillation," "Bioprosthetic Valve" for literature published prior to January 2021. Extraction of data from included studies was carried out independently by three reviewers from Covidence. We assessed the methodical rigor of the included studies using the modified Downs and Black checklist. Results Four RCTs and one observational study (n=1776) were included in our study. A random-effect model using RevMan (version 5.4; The Nordic Cochrane Centre, The Cochrane Collaboration, Copenhagen) was used for data analysis. The pooled data showed that there was a non-significant reduction in the incidence of stroke and systemic embolism in the patients taking DOACs as compared to warfarin (HR 0.69; 95% CI, 0.29, 1.67; I = 50%). The incidence of major bleeding was lower in the DOACs group; the difference was statistically significant (HR 0.42; 95% CI, 0.26, 0.67; I = 7%). The difference was not statistically significant for all-cause mortality in both groups (HR 1.24; 95% CI, 0.91, 1.67; I = 0%). Conclusion Our results showed that there was no difference in the outcomes of stroke and systemic embolism between DOACs and warfarin but there were statistically significantly lower major bleeding events. We conclude that larger clinical trials are needed to assess the true safety and efficacy of DOACs in patients with AF and bioprosthetic valves.