Balloon-expanding transcatheter aortic valve implantation for degenerated Mitroflow bioprostheses: clinical and echocardiographic long-term outcomes.

OBJECTIVES: This study aims to analyse the risks associated with valve-in-valve procedures for treating structural valve deterioration in Mitroflow bioprostheses, as well as to determine the impact of the original Mitroflow size on the patients' long-term outcomes.

METHODS: Between January 2012 and September 2019, 21 patients (61.9% males; mean age 82.4 ± 5.4 years) were treated for Mitroflow deterioration with valve-in-valve procedures (12 transapical and 9 transfemoral).

RESULTS: Mean EuroSCORE I and EuroSCORE II were 28.2% ± 13.6% and 10.5% ± 6.1%, respectively. Six patients presented an indexed aortic root diameter <14 mm/m2 and 7 patients a diameter of sinus of Valsalva <30 mm. Implanted transcatheter valve sizes were 20 mm in 6 cases, 23 mm in 14 cases and 26 mm in 1 patient. A Valve Academic Research Consortium-2 complication occurred in 23.8% of cases, including 3 coronary occlusions. In-hospital mortality was 9.5%. The 20 mm transcatheter valves presented significantly higher postoperative peak and mean aortic gradients than other sizes (54.1 ± 11.3 mmHg vs 29.9 ± 9.6 mmHg, P = 0.003; and 29.3 ± 7.7 mmHg vs 17.4 ± 5.9 mmHg, P = 0.015, respectively). There were 12 cases of patient-prosthesis mismatch (57.1%) and 3 cases (14.3%) of severe patient-prosthesis mismatch. Cumulative survival was 85.7% ± 7.6% at 1 year, 74.3% ± 10% at 2 years and 37.1% ± 14.1% at 5 years.

CONCLUSIONS: Valve-in-valve procedures with balloon-expandable transcatheter valves associate a high risk of coronary occlusion in patients with indexed aortic root diameter <14 mm/m2 and low coronary ostia <12 mm. Valve-in valve procedures with 20 mm balloon-expandable transcatheter valves in ≤21 mm Mitroflow bioprosthesis leave significant residual transvalvular gradients that might obscure patients' long-term outcomes.