Transapical Transcatheter Valve-in-Valve Implantation for Failed Mitral Bioprostheses: Gradient, Symptoms, and Functional Status in 18 High-Risk Patients Up to 5 Years.

BACKGROUND: The recourse to mitral valve-in-valve implantation is expected to rise consistently owing to the increasing use of bioprostheses and to the risks related to redo valve replacement. However, there is concern that the excellent early results of mitral valve-in-valve could be nullified by the development of significant gradients. We report our experience with mitral valve-in-valve implantation, with particular emphasis on the midterm follow-up.

METHODS: Eighteen patients underwent mitral valve-in-valve implantation at our institution. The mean Society of Thoracic Surgeons score was 10.3. All patients were heavily symptomatic. The mechanisms of bioprosthesis failure were stenosis (3 patients), regurgitation (4 patients) or mixed (11 patients). The mean transprosthetic gradient was 12.8 ± 5.7 mm Hg. All the procedures were transapical. Balloon predilation was never used.

RESULTS: In the first patient, the transcatheter valve embolized in the ventricle. The patient died 2 days later of multiorgan failure. There were no other hospital deaths. Four patients died of pneumonia, endocarditis, lung cancer, and stroke at 1, 8, 18, and 46 months, postoperatively. The mean gradient at discharge was 5.1 ± 2.3 mm Hg. At follow-up (median 27 months), all surviving patients were in New York Heart Association functional class II or less. The mean transprosthetic gradient was 7 ± 1.8 mm Hg, and 1 patient had a gradient more than 10 mm Hg.

CONCLUSIONS: Mitral valve-in-valve implantation allows good clinical and hemodynamic results. In our series, the appearance of a significant gradient at follow-up was not associated with echocardiographic signs of structural deterioration, and was possibly related to the size of the transcatheter and recipient valve.