Transcatheter mitral valve-in-valve and valve-in-ring replacement: Lessons learned from bioprosthetic surgical valve failures

Introduction: Limited data are available about the outcomes of transcatheter mitral valve replacement (TMVR) using transseptal approach in patients with prior mitral valve repair (valve-in-ring) or replacement (valve-in-valve) (TMViVR) and on modes of the prior surgical valve failures. We report our tertiary center TMVR experience in high surgical risk patients with prior mitral valve repair or replacement. Methods: From December 2016 to January 2020, patients with symptomatic severe mitral valve stenosis and/or insufficiency at increased redo surgical risk were included. TMViVR was performed off-label with Sapien S3 valve (Edwards Lifesciences). Patients were followed within 30-days and 1-year from the procedure. Results: Twenty-seven patients underwent transcatheter mitral valve-in-valve (n = 21) or valve-in-ring (n = 6) replacement. Mean ± SD age was 71.8 ± 11 years with Society of Thoracic Surgeons’ calculated mortality 7.1 ± 4.6%. The etiology of valve failure was stenosis in 17 (63%) patients, insufficiency in 4 (14.8%) patients, and both in 6 (22.2%) patients. TMViVR technical success was 100% in all patients. Left ventricular outflow track (LVOT) obstruction was observed in only one (3.7%) patient. Zero patients had moderate or severe central mitral valve regurgitation or paravalvular leak. All patients had symptomatic improvement at 30 days. The mean transmitral diastolic pressure gradient decreased from 14.1 ± 4.6 to 6.9 ± 4.6 mm Hg (p <.001) at 30 days. The one patient with LOVT obstruction required readmission at 5-months. One-year survival was 95%. At 1-year mean gradients remained lower than the baseline (7.0 ± 3.0 vs. 12.4 ± 4.0, p =.002). Conclusions: Transcatheter mitral valve-in-valve and valve-in-ring replacement is feasible and safe. The improvement in mitral valve hemodynamics appears to be durable.