Transcatheter Mitral Valve Replacement in Failed Mitral Bioprosthesis: Case Report

Transcatheter valve-in-valve mitral valve replacement (ViV TMVR) is an established therapeutic alternative for selected patients with symptomatic degeneration of a surgical mitral bioprosthesis and high or prohibitive surgical risk. We present a 75-year-old woman with a failed Pericarbon More 29-mm mitral bioprosthesis and severe prosthetic mitral stenosis, which was resolved with transseptal transcatheter ViV TMVR. Baseline echocardiography showed mitral valve area 0.45 cm² by pressure half-time, mean transmitral gradient 13 mmHg, preserved left ventricular systolic function, estimated systolic pulmonary artery pressure of 55 mmHg, and severe tricuspid regurgitation. ECG-gated computed tomography was performed for proper procedural planning. During the procedure, after dilation of the interatrial septum, an abrupt left-to-right shunt caused hemodynamic compromise. Rapid rescue balloon dilation of the stenotic mitral bioprosthesis and subsequent implantation of a 26-mm SAPIEN 3 valve restored forward transmitral flow, reduced the interatrial shunt to a minimum, and avoided septal occluder implantation. Postprocedural echocardiography showed a mean transmitral gradient of 3.5 mmHg, no intraprosthetic or paravalvular regurgitation, no LVOT obstruction, and a minimal, hemodynamically insignificant residual shunt. At 6-month, 12-month, and 2-year follow-ups, the patient remained asymptomatic with stable prosthetic valve function, although the estimated pulmonary artery pressure remained mildly to moderately elevated and tricuspid regurgitation persisted at a moderate degree. Beyond demonstrating the feasibility of valve-in-valve TMVR, this case highlights that septal dilation in severe prosthetic mitral stenosis can precipitate abrupt hemodynamic deterioration by creating a clinically significant left-to-right interatrial shunt before relief of the mitral obstruction.