Mechanical versus biological aortic valve replacement in patients aged 50–70 years: a systematic review and meta-analysis

Objectives The optimal prosthetic aortic valve replacement (AVR) for long-term outcomes in patients aged 50–70 years remains uncertain. International guidelines differ; contemporary randomised trials are lacking, and use of bioprosthetic valves has increased. This review synthesised evidence comparing efficacy and safety outcomes between valve types in this age group. Methods A systematic review and meta-analysis of randomised and observational studies comparing mechanical and bioprosthetic AVR in patients aged 50–70 years was conducted. Medline, Embase and the Cochrane Library were searched. The primary outcome was overall survival; secondary outcomes were major bleeding, reoperation and stroke. Data were pooled using inverse variance random-effects meta-analysis and presented as HRs with 95% CIs. Results 30 studies involving 120 844 patients were included, 29 of which were observational. Mechanical valves were associated with better overall survival (HR 0.88; 95% CI 0.81 to 0.94; p=0.001). Stroke rates did not differ significantly (HR 1.07; 95% CI 0.91 to 1.27; p=0.37). Mechanical valves carried a higher risk of major bleeding (HR 1.60; 95% CI 1.43 to 1.78; p<0.001), while bioprosthetic valves had higher reoperation rates (HR 0.44; 95% CI 0.33 to 0.57; p<0.001). Conclusions Drawing largely from observational data, mechanical valves were associated with superior overall survival but increased bleeding due to lifelong anticoagulation. Bioprosthetic valves offer lower bleeding risk but higher reoperation rates from structural degeneration. The growing use of bioprosthetic valves in this age group may lead to more reinterventions in older, more comorbid patients. Contemporary randomised trials are needed to evaluate outcomes with modern valve designs. PROSPERO registration number CRD42024540272.