Bioprosthetic vs Mechanical Aortic Valve Replacement in Patients 40 to 75 Years of Age

Background: The choice of bioprosthetic or mechanical surgical aortic valve replacement (AVR) should balance individual valve durability with the potential liabilities of oral anticoagulation. Objectives: To inform clinical practice, this study sought to evaluate contemporary, real-world, long-term AVR outcomes from the Society of Thoracic Surgeons Adult Cardiac Surgery Database (STS ACSD). Methods: All patients undergoing primary isolated bioprosthetic or mechanical AVR were identified. Patients aged <40 and >75 years with endocarditis, emergency/salvage status, shock, ejection fraction ≤25%, and any prior cardiac surgery were excluded. Validated methodology was applied for linkage to the National Death Index to define longitudinal all-cause mortality (2008-2019). Robust risk adjustment was performed by using age-specific inverse probability weighting and restricted cubic splines to model nonlinear age relationships. Sensitivity analyses excluded pure aortic insufficiency, intermediate/high risk (STS predicted risk of operative mortality >4%), and discontinued valve types. Results: A total of 109,842 patients underwent bioprosthetic (n = 94,125) or mechanical (n = 15,717) AVR during the study period. After risk adjustment, freedom from all-cause mortality favored mechanical valves in patients aged 60 years and younger. Age group–specific analyses showed that mechanical valves were associated with lower all-cause mortality in all age groups ≤60 years. These results remained consistent across all sensitivity analyses. Conclusions: In patients aged ≤60 years, mechanical AVR was associated with an independent risk-adjusted survival benefit compared with bioprosthetic AVR. These contemporary 12-year survival data further inform patient and provider shared clinical decision-making regarding prosthetic aortic valves.