Selection of prosthetic valve type for aortic valve replacement (AVR) in patients aged 50-70 years remains clinically challenging, given variation in guideline recommendations and limited randomized evidence. A systematic review and meta-analysis published in Heart evaluated long-term survival and complication outcomes with mechanical versus bioprosthetic valves in this age group.

Searches of Medline, Embase, and the Cochrane Library identified 30 studies including 120,844 patients, of which 29 were observational. Outcomes were pooled using inverse variance random-effects models and expressed as hazard ratios (HRs) with 95% confidence intervals (CIs).

Mechanical valves were associated with better overall survival compared with bioprosthetic valves (HR 0.88; 95% CI 0.81-0.94; p=0.001). Stroke rates did not differ significantly between groups (HR 1.07; 95% CI 0.91-1.27; p=0.37). Mechanical valves were also associated with a higher risk of major bleeding (HR 1.60; 95% CI 1.43–1.78; p<0.001), while bioprosthetic valves were associated with higher reoperation rates (HR 0.44; 95% CI 0.33-0.57; p<0.001).

The evidence base was predominantly observational, with only one randomized study included. Increasing use of bioprosthetic valves in this age group may contribute to a higher reintervention burden, particularly in older patients with greater comorbidity.

Mechanical valves were associated with better overall survival but higher bleeding risk, whereas bioprosthetic valves were associated with lower bleeding risk and higher reoperation rates. These findings are derived largely from observational data, and further randomized trials are needed to evaluate outcomes with contemporary valve designs.