To assess the results of transcatheter aortic valve implantation (TAVI) using the Medtronic CoreValve System (MCS), through the transarterial approach, in high-risk patients with degenerated surgically implanted aortic bioprostheses (SP). Of 241 patients who underwent TAVI, 10 (4%) had a degenerated SP. The approach was percutaneous transfemoral in 9 cases and surgical transaxillary in 1. Patients were age 75±10 years of age. All were in New York Heart Association classes III or IV and at high risk for repeated surgery. Seven patients had stented, 2 stentless, and 1 homograft SP. The failure mode was predominant regurgitation in 7 cases and stenosis (aortic valve area, 0.7±0.2 cm(2); mean gradient, 58±16 mm Hg) in 3. Based on the echographic measurements, 8 patients received a 26-mm, and 2 a 29-mm-diameter MCS. Procedural success rate was 100%. There was 1 in-hospital death, 1 stroke with moderate sequelae, and 1 pacemaker implantation. There were no other adverse events at 30 days. The mean postimplantation transprosthetic gradient was 13±7 mm Hg; periprosthetic regurgitation was absent or trivial in 9 cases and grade 2 in 1. After a median follow-up of 5 months, there were no additional adverse events. All but 1 of the hospital survivors were in New York Heart Association classes I or II. These results suggest that transarterial MCS implantation in degenerated SP is feasible and may lead to hemodynamic and clinical improvement in patients who are poor candidates for repeated surgery, pending confirmation in larger series with longer follow-up.