On the spectrum of transcatheter mitral valve replacement: In silico and in vitro assessment of neo-LVOT area in ViR, ViV and ViMAC

The assessment of the neo-left ventricular outflow tract (neo-LVOT) area is an essential metric for pre-procedural imaging when screening patients for transcatheter mitral valve replacement (TMVR) eligibility. Indeed, the implantation of transcatheter heart valves for treating failed annuloplasty band ring (ViR), bioprosthesis (ViV) and mitral valve calcification (ViMAC) can lead to a permanent obstruction of the implanted device (namely, LVOT obstruction). In this study, in silico computational modeling and 3D printing were used to quantify the neo-LVOT area and the resulting hemodynamic outcomes of TMVR. We first simulated the deployment of the SAPIEN 3 Ultra device (Edwards Lifesciences, Irvine, CA) and then evaluated the pressure drop near the LVOT obstruction using computational fluid dynamics. The neo-LVOT area was largest in patients with ViR (453.4 ± 58.1 mm2) compared to patients with ViV (246.6 ± 109.5 mm2) and ViMAC (155.6 ± 46.1 mm2). The pressure drop near the LVOT obstruction differed among patients with TMVRs and significantly correlated with the magnitude of the neo-LVOT area (R = −0.761 and P-value = 0.047). The present study highlights the potential of in silico and 3D printed models for planning TMVR procedures and for carrying out a risk evaluation of the device protrusion into the left heart when treating failed mitral valves.