Biological prostheses are preferred for surgical aortic valve replacement (SAVR) in patients aged >70 years in clinical practice. We studied differences in long-term outcomes between SAVR patients aged >70 years who received mechanical and biological prosthetic valves.

All patients (excluding endocarditis) aged >70 years with isolated first-time SAVR (±coronary artery by-pass grafting) in Finland between 2004-2014 were retrospectively studied (n=4227). Propensity score matching (1:3) was used to account for baseline differences (n=296 with mechanical and n=888 with biological prosthesis). Outcomes were 10-year survival, major bleeding (all, gastro-intestinal, intracranial), ischemic stroke, infective endocarditis, and aortic valve re-operation. Mean age was 75.8 years and mean follow-up 8.3 years.

Survival at 10-years was 46.1% with mechanical and 57.8% with biological prosthesis (HR 1.48; CI 1.21-1.80; p=0.0001, NNT for harm = 7.0). Ten-year major bleeding rates were 37.0% with mechanical and 18.8% with biological valves (HR 1.77; CI 1.25-2.49; p=0.001, NNT for harm = 7.4). Both gastro-intestinal (26.5% vs. 8.9%; HR 2.63; CI 1.63-4.23; p<0.0001) and intracranial bleeding (8.8% vs. 6.0%; HR 2.12; CI 1.09-4.15; p=0.028) were significantly more frequent with mechanical valve prosthesis. Occurrence of ischemic stroke (18.9% with mechanical vs. 16.1% with biological prosthesis; p=0.341), infective endocarditis (3.7% vs. 2.8%; p=0.242), and aortic valve re-operation (0.8% vs. 2.8%; p=0.707) did not differ between study groups.

Mechanical aortic valve prosthesis is associated with worse long-term survival and increased bleeding after SAVR in patients aged >70 years. Our results suggest caution when considering mechanical aortic valve prostheses in elderly patients.