The aim of this study was to examine 1-year outcomes of transseptal balloon-expandable transcatheter heart valve implantation in failed mitral bioprosthesis, ring annuloplasty, and mitral annular calcification (MAC). Immediate outcomes following transseptal mitral valve implantation in failed bioprostheses are favorable, but data on subsequent outcomes are lacking. Percutaneous transseptal implantation of balloon-expandable transcatheter heart valves was performed in 87 patients with degenerated mitral bioprostheses (valve in valve VIV) (n = 60), previous ring annuloplasty (valve in ring) (n = 15), and severe MAC (valve in MAC) (n = 12). The mean Society of Thoracic Surgeons risk score was 13 ± 8%, and the mean age was 75 ± 11 years. Acute procedural success was achieved in 78 of 87 patients (90%) in the overall group and 58 of 60 (97%) in the VIV group, with a success rate of 20 of 27 (74%) in the valve in ring/valve in MAC group. Thirty-day survival free of death and cardiovascular surgery was 95% (95% confidence interval CI: 92% to 97%) in the VIV subgroup and 78% (95% CI: 70% to 86%) in the valve in ring/valve in MAC group (p = 0.008). One-year survival free of death and cardiovascular surgery was 86% (95% CI: 81% to 91%) in the VIV group compared with 68% (95% CI: 58% to 78%) (p = 0.008). At 1 year, 36 of 40 patients (90%) had New York Heart Association functional class I or II symptoms, no patients had more than mild residual mitral prosthetic or periprosthetic regurgitation, and the mean transvalvular gradient was 7 ± 3 mm Hg. One-year outcomes following successful transseptal balloon-expandable transcatheter heart valve implantation in high-risk patients with degenerated mitral bioprostheses are excellent, characterized by durable symptom relief and prosthesis function. Although mitral valve in ring and valve in MAC have higher operative morbidity and mortality, 1-year outcomes after an initially successful procedure are favorable in carefully selected patients. Display omitted