Long-Term Outcomes of Mechanical Versus Bioprosthetic Aortic Valve Replacement in Patients Aged Under 50 Years: Meta-Analysis of Reconstructed Time-to-Event Data.

To compare the long-term outcomes of mechanical versus bioprosthetic aortic valve replacement (AVR) in patients aged <50 years, we performed a study-level meta-analysis with reconstructed time-to-event data including studies published by December of 2023. The primary outcome was overall survival. Secondary outcomes included reoperation, major bleeding, and stroke. A total of 5 studies met our inclusion criteria, with a total of 4,245 patients (2,311 mechanical and 1,934 bioprosthetic). All studies were observational and the mean age of groups across the studies ranged from 38.2 to 43.0 years. The median follow-up time was 11.4 years (interquartile range 6.9 to 15.0). Bioprosthetic AVR was associated with reduced overall survival and higher risk of all-cause death (hazard ratio [HR] 1.170 95% confidence interval [CI] 1.002 to 1.364, p = 0.046), increased risk of reoperation over time (HR 2.581, 95% CI 2.102 to 3.168, p <0.001), decreased risk of major bleeding (HR 0.500, 95% CI 0.367 to 0.682, p <0.001), and decreased risk of stroke (HR 0.751, 95% C, 0.565 to 0.998, p = 0.049) compared with mechanical AVR in patients aged <50 years. In conclusion, for patients aged <50 years, bioprosthetic AVR is associated with increased mortality and risk of reoperation compared with mechanical valves. In contrast, mechanical AVR is associated with an increased risk of major bleeding events and stroke. These aspects should be carefully considered during the selection of valve type in this age group; however, we should keep in mind that the statistically significant differences in the risk of all-cause death and stroke might not be clinically relevant (because of marginal statistical significance).