Randomized controlled, multi-center trial randomizing patients with symptomatic severe aortic stenosis at low to intermediate operative risk of mortality, as assessed by the STS-PROM-Score, in a 1:1 fashion to transcatheter aortic valve implantation (TAVI) or surgical aortic valve replacement (SAVR) to test, whether TAVI is non-inferior to SAVR regarding short and long-term mortality (1 and 5 year).