Surgical mitral valve repair is the gold standard for severe primary mitral regurgitation (MR), yet when repairs fail, open reintervention carries substantial perioperative risk. Following band annuloplasty, minimally invasive options, such as transcatheter mitral valve replacement (TMVR), remain largely unexplored due to a hypothetical concern around the lack of circumferential radial support. Although transapical transcatheter mitral valve-in-band (ViB) replacement has been reported in a single human case, we report the first controlled large-animal model of ViB. A 68 kg, 20-month-old female Yucatan mini pig underwent placement of a 28 mm mitral annuloplasty band, oversized to create MR, via clamshell sternotomy under cardiopulmonary bypass; a simulated dilated left atrium enabled transcatheter access. A 23 mm Edwards SAPIEN 3 Ultra valve was deployed within the band using the Commander delivery system under fluoroscopic guidance. The valve achieved stable fixation without embolization, paravalvular leak (PVL), or left ventricular outflow tract (LVOT) obstruction with resolution of MR on echocardiography. The stable position was consistent with a contribution from the native anterior leaflet and annulus, although radial forces were not directly measured. The animal tolerated the procedure without complications. This first-in-animal study suggests the acute technical feasibility of TMVR within a mitral annuloplasty band and supports further investigation of percutaneous band modification strategies to optimize ViB outcomes.

Surgical mitral valve repair is the gold standard for severe primary mitral regurgitation (MR), yet when repairs fail, open reintervention carries substantial perioperative risk. Following band annuloplasty, minimally invasive options, such as transcatheter mitral valve replacement (TMVR), remain largely unexplored due to a hypothetical concern around the lack of circumferential radial support. We report the first transcatheter mitral valve-in-band (ViB) replacement in a large-animal model of failed mitral repair. A 68 kg, 20-month-old female Yucatan mini pig underwent placement of a 28 mm mitral annuloplasty band, oversized to create MR, via clamshell sternotomy under cardiopulmonary bypass; a simulated dilated left atrium enabled transcatheter access. A 23 mm Edwards Sapien Ultra valve was deployed within the band using the Commander delivery system under fluoroscopic guidance. The valve achieved stable fixation without embolization, paravalvular leak (PVL), or left ventricular outflow tract (LVOT) obstruction with resolution of MR on echocardiography. The native anterior leaflet and annulus contributed circumferential radial support, and the animal tolerated the procedure without complications. This first-in-animal study demonstrates the technical feasibility and acute safety of TMVR within a mitral annuloplasty band and supports further investigation of percutaneous band modification strategies to optimize ViB outcomes.