Antithrombotic management after aortic valve replacement with biological prosthesis: a meta-analysis

BACKGROUND: We aimed to summarise the existing knowledge regarding antithrombotic medications following surgical aortic valve replacement (SAVR) using a biological valve prosthesis. METHODS: We performed a meta-analysis of studies that reported the results of using antithrombotic medication to prevent thromboembolic events after SAVR using a biological aortic valve prosthesis and recorded the outcomes 12 months after surgery. Since no randomised controlled trials were identified, observational studies were included. The analyses were conducted separately for periods of 0-12 months and 3-12 months after surgery. A random effects model was used to calculate pooled outcome event rates and 95% confidence intervals (CIs). RESULTS: The search yielded eight eligible observational studies covering 6727 patients overall. The lowest 0- to 12-month mortality was observed in patients with anticoagulation (2.0%, 95% CI 0.4-9.7%) and anticoagulation combined with antiplatelet therapy (2.2%, 95% CI 0.9-5.5%), and the highest was in patients without antithrombotic medication (7.3%, 95% CI 3.6-14.2%). Three months after surgery, mortality was lower in anticoagulant patients (0.5%, 95% CI 0.1-2.6%) than in antiplatelet patients (3.0%, 95% CI 1.2-7.4%) and those without antithrombotics (3.5%, 95% CI 1.3-9.3%). There was no eligible evidence of differences in stroke rates observed among medication strategies. At 0- to 12-month follow-up, all antithrombotic treatment regimens resulted in an increased bleeding rate (antiplatelet 4.2%, 95% CI 2.9-6.1%; anticoagulation 7.5%, 95% CI 3.8-14.4%; anticoagulation combined with antiplatelet therapy 8.3%, 95% CI 5.7-11.8%) compared to no antithrombotic medication (1.1%, 95% CI 0.4-3.4%). At 3- to 12-month follow-up, there was up to an eight-fold increase in the bleeding rate in patients with anticoagulation combined with antiplatelet therapy when compared to those with no antithrombotic medication. Overall, the evidence certainty was ranked as very low. CONCLUSION: Although this meta-analysis reveals that anticoagulation therapy has a beneficial tendency in terms of mortality at 1 year after biological SAVR and suggests potential advantages in continuing anticoagulation beyond 3 months, it is limited by very low evidence certainty. The imperative for cautious interpretation and the urgent need for more robust randomised research underscore the complexity of determining optimal antithrombotic strategies in this patient population.