Antithrombotic Treatment After Valve-in-Valve, Valve-in-Ring, and Valve-in-MAC Procedures: A Systematic Review and Meta-Analysis.

Introduction: While antithrombotic therapy following transcatheter valve implantation has been extensively studied in various clinical trials, there remains a notable gap in evidence regarding the optimal approach following valve-in-valve (ViV), valve-in-ring (ViR) and valve-in-mitral annular calcification (ViMAC) procedures, warranting further assessment. This gap is particularly concerning due to the apparent increased risk of thrombosis associated with ViV interventions. The aim of this systematic review was to explore the potential benefits of anticoagulation in ViV, ViR, and ViMAC procedures.

Methods: We searched PubMed, Embase, and the Cochrane Central Register of Controlled Trials, as well as the grey literature, for observational and interventional studies published until December 2023. Trials were included if a comparative analysis between the two antithrombotic strategies was feasible and excluded if patients under 18 years old were analysed. The primary efficacy endpoints were incidence of clinical and total valve thrombosis (VT), major bleeding was the sole safety primary endpoint. Additional analyses were performed regarding valves in the mitral position and valve type. The risk of bias was evaluated using the Newcastle-Ottawa scale. Data was assessed using the Review Manager 5.4 software.

Results: A total of five observational and one case series were included (n = 614 on anticoagulation and n = 468 on antiplatelets), comprising a total of 1082 participants. Clinical VT rates were 4.2% for all procedures, and patients on anticoagulants were associated with a a lower risk of clinical VT (1.1% vs 8.3%; OR: 0.18; 95% CI: 0.07 - 0.42, I2: 0%) and total VT (1.3% vs 8.5%; OR: 0.16; 95% CI: 0.07 - 0.37, I2: 0%). Regarding bleeding events, the existing literature did not provide adequate information to enable a thorough analysis.

Conclusion: Our study suggests a potential benefit of anticoagulation regimens to decrease the high rates of VT following valve-in-valve, valve-in-ring and valve-in-mitral annular calcification procedures. However, the lack of randomized controlled trials and data on bleeding and mortality emphasises the necessity for further research.