Biological or mechanical prostheses for isolated aortic valve replacement in patients aged 50–65 years: the ANDALVALVE study

OBJECTIVES: The decision about whether to use a biological or a mechanical prosthesis for aortic valve replacement remains controversial in patients between 50 and 65 years of age and has yet to be addressed in a Mediterranean population. This research aimed to analyse long-term survival and major morbidity rates (30-day mortality, stroke, any prosthetic reoperation and major bleeding) within this population. METHODS: Our multicentre observational retrospective study included all subjects aged 50-65 years who had a primary isolated aortic valve replacement due to severe aortic stenosis at 7 public hospitals from Andalusia (Spain) between 2000 and 2015. Concomitant surgery, reoperations and endocarditis were the exclusion criteria. A total of 1443 patients were enrolled in the study (272 with biological and 1171 with mechanical valves). Multivariate analyses including a 2:1 propensity score matching (506 mechanical and 257 biological prostheses) were conducted. RESULTS: Bioprostheses were implanted in 18.8% (n = 272): 35% were women; the mean EuroSCORE-I was 3%. The mean follow-up was 8.1 ± 4.9 years in a matched sample: 8.8 ± 4.9 years in those receiving a mechanical vs 7.1 ± 4.5 years in those receiving a biological prosthesis (P = 0.001). In the paired sample, the 15-year survival rate was 73% in those who had a biological vs 76% in those who had a mechanical valve [hazard ratio (HR) 0.80, 95% confidence interval (CI) 0.54-1.20; P = 0.159]. No significant differences were observed in patients ≥55 years old (74% of 15-year survival in both groups: HR 0.88, 95% CI 0.56-1.34; P = 0.527). A higher rate of major bleeding was found in patients with a mechanical prosthesis (P = 0.004), whereas reoperation was more frequent among those with a biological prosthesis (P = 0.01). CONCLUSIONS: Long-term survival was comparable in patients above 55 years of age. Mechanical prostheses were associated with more major bleeding and bioprostheses, with more reoperations. A bioprosthesis in patients above 55 years old is a reasonable choice. CLINICAL TRIAL REGISTRATION NUMBER: NCT03239509.