This trial compares two types of transcatheter aortic valve implantation (TAVI) in terms of device success. TAVI is a treatment for degenerated aortic bioprostheses in elderly patients. The primary endpoint is device success at 30 days, defined as the absence of procedural mortality, correct positioning of a single prosthetic heart valve, and intended performance of the prosthetic heart valve. The safety endpoint at 1 year is defined as the composite of all-cause death, disabling stroke, rehospitalization for heart failure or valve related problems.