Mechanical vs Bioprosthetic Aortic Valve Replacement in Patients Younger Than 70 Years of Age: A Hazard Ratio Meta-analysis

BACKGROUND: The choice between mechanical valves (MVs) and bioprosthetic valves (BVs) in patients undergoing aortic valve surgery is complex, requiring a balance between the inferior durability of BV and the indicated long-term anticoagulation therapy with MV. This is especially challenging in the middle age group (< 70 years), which has seen an increased use of BV over recent years.

METHODS: A meta-analysis of randomised controlled trials (RCTs), observational studies using propensity score matching (PSM) and inverse probability weighting (IPW) was conducted to examine the clinical outcomes of patients < 70 years of age undergoing aortic valve replacement. The primary outcome was overall long-term mortality. Secondary outcomes included bleeding events, reoperation, systemic thromboembolism, and cerebrovascular accident.

RESULTS: Fifteen studies (1 RCT, 12 PSM studies, and 2 IPW studies; aggregated sample size 16,876 patients) were included. Median follow-up was 7.8 years. Mortality was higher with BVs vs MVs (hazard ratio [HR] 1.22, 95% confidence interval [CI] 1.00-1.49), as was reoperation (HR 3.05, 95% CI 2.22-4.19). Bleeding risk was lower with BVs (HR 0.58, 95% CI 0.48-0.69), and the risk of stroke was similar in both valve types (HR 0.96, 95% CI 0.83-1.11) CONCLUSIONS: This broadest meta-analysis comparing BV and MV suggests a survival benefit for MVs in patients < 70 years of age. This should lead to reassessment of current patterns used in the choice of valves for patients < 70 among the cardiothoracic surgery community.