Comparative effectiveness among thromboprophylaxis strategies after the Fontan operation: A systematic review and network meta-analysis

Introduction: A variety of thromboprophylaxis regimens have been administered in patients following the Fontan procedure. However, consensus guidelines regarding the optimal thromboprophylaxis strategy have not yet been developed. Method: A network meta-analysis was conducted to evaluate the comparative effectiveness among available thromboprophylaxis regimens and major bleeding events associated with these regimens. Results: A total of 28 comparative studies with 4430 Fontan patients were included. The incidence of thromboembolic events (TE) was significantly lower in individuals who underwent thromboprophylaxis compared to those who did not. Compared to a no-treatment strategy, nonvitamin K oral anticoagulants (NOACs) showed the largest treatment effect for preventing TE (OR = 0.08, 95 % CI 0.03 to 0.21), followed by warfarin (OR = 0.16, 95 % CI 0.10 to 0.27), and aspirin (OR = 0.23, 95 % CI 0.14 to 0.38). Indeed, NOACs were significantly more effective than aspirin in preventing TE (OR = 0.35, 95 % CI 0.14 to 0.84). Aspirin was associated with the lowest occurrence of major bleeding events, followed by NOACs, no medication, and warfarin. NOACs were shown to possess a highly favorable overall profile. Conclusion: Prescribing thromboprophylaxis drugs, either antiplatelets or anticoagulants, may be more effective in preventing TE after the Fontan operation than not doing so. Among the included regimens, NOACs demonstrated significantly greater efficacy than aspirin; however, they did not show statistically significant superiority over warfarin. Aspirin exhibited lower rates of major bleeding compared to both NOACs and warfarin. Overall, NOACs tended to offer the most advantageous balance of efficacy and safety. However, the findings should be interpreted considering the certainty and limitations of the evidence, including potential residual confounding in observational studies.