BACKGROUND: Aortic valve replacement (AVR) is the definitive therapy for patients with severe aortic valve stenosis (AoS). The aim of this work is to compare the effect of a mechanical prosthesis (MP) and a bioprosthesis (BP) on the survival of patients aged 50-65 years after AVR. METHODS: The retrospective analysis included 276 patients aged 50 to 65 years who had undergone isolated AVR for AoS; 161 patients were implanted with an MP and 115 with a BP. Patient survival, adjusted for age, gender and risk parameters affecting survival, was assessed. A subgroup analysis was performed on the 208 patients with a modern valve (prosthesis models that are no longer used in clinical practice were removed from the sample). RESULTS: After adjusting for risk factors for overall survival as well as for age and sex, the implantation of an MP did not have a significant effect on overall survival in comparison to a BP, at a median follow-up of 10.3 years (p = 0.477). The size of the MP had no significant effect on overall survival either (HR: 1.29; 95%CI: 0.16-10.21; p = 0.812). However, the indexed effective orifice area of the BP had a positive effect on overall survival (HR: 0.09; 95%CI: 0.01-0.78; p = 0.029). CONCLUSIONS: The estimated survival of patients aged between 50 and 65 years after implantation of a BP with a sufficiently large indexed effective orifice area may exceed that of patients with an MP.

2 Surgery Department Cardiovascular Surgery General University Hospital and 1st Faculty of Medicine Charles University 128 08 Prague Czech Republic

Department of Heart Surgery East Slovak Institute for Cardiovascular Diseases and Medical Faculty of Pavol Jozef Šafárik University 04001 Košice Slovakia

Institute of Mathematics and Statistics Faculty of Science Masaryk University 602 00 Brno Czech Republic

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