The optimal choice of valve prosthesis in surgical aortic valve replacement for infective endocarditis (IE) is controversial. We studied outcomes after mechanical versus biological prosthetic valve surgical aortic valve replacement in IE patients.

All patients with native-valve IE aged 16-70 years undergoing mechanical or biological surgical aortic valve replacement in Finland, between 2004 and 2014, were retrospectively studied (n = 213). Outcomes were all-cause mortality, ischaemic stroke, major bleeding and aortic valve reoperation at 1 year and 5 years. Results were adjusted for baseline features (age, sex, comorbidity burden, atrial fibrillation, valvular stenosis, concomitant coronary artery bypass grafting, extension, urgency, year and centre of operation). Median follow-up was 5 years.

The 5-year mortality rate was 19.0% with mechanical prostheses and 34.8% with biological prostheses [hazard ratio (HR) 0.47, 95% confidence interval (CI) 0.23-0.92; P = 0.03]. Ischaemic stroke rates were 8.3% with mechanical prostheses and 16.8% with biological prostheses at 5 years (HR 0.21, CI 0.06-0.79; P = 0.01). Results were comparable in patients aged 16-59 and 60-70 years (interaction P = 0.84). Major bleeding within 5 years was similar between mechanical (11.3%) and biological valve (13.4%) groups (P = 0.95) with comparable rates of both gastrointestinal and intracranial bleeds. Reoperation rates at 5 years were 5.0% for mechanical prostheses and 9.2% for biological prostheses (P = 0.14). The 1-year ischaemic stroke rate was lower with mechanical prostheses (3.6% vs 11.6%, P =0.03), whereas mortality, major bleeding and reoperation rates were similar between groups.

The use of mechanical aortic valve is associated with lower mid-term mortality compared to biological prosthesis in patients with native-valve IE aged ≤70 years. Our results do not support the routine choice of a biological aortic valve prosthesis in this patient group.