Numerical simulation of transcatheter mitral valve replacement: The dynamic implication of LVOT obstruction in the valve-in-ring case.

Transcatheter mitral valve replacement (TMVR) has been used for "off-label" treatment when annuloplasty band ring for mitral repair fails. However, the complex anatomy and function of the mitral valve may lead to fatal complications as a result of the left ventricular outflow tract (LVOT) obstruction in TMVR. We report the structural and hemodynamic response of LVOT obstruction resulting from TMVR with the Edwards SAPIEN 3 Ultra (S3) device. We modified the original Living Heart Human Model (LHHM) to account for a failed mitral valve with an annuloplasty band ring and simulated the cardiac beating condition in the setting of S3 device implantation. Findings demonstrated a high dynamic behavior of the newly formed LVOT (neoLVOT) as confined by the displaced mitral valve and the interventricular septum. During the cardiac beat, the neoLVOT area oscillated from a maximum of 472.1 mm2 at early systole to the minimum of 183 mm2 at end-systole. The profile of both anchoring force and contact pressure revealed that the band ring serves as the anchoring zone while mitral valve is primally displaced by the deployed device. At early systole, computational flow dynamics highlighted hemodynamic disturbances associated with the LVOT obstruction, with a skewed flow towards the septum and a pressured drop of 4.5 mmHg between the left ventricular apex and the neoLVOT region. This study can lead to a more accurate assessment of the risk induced by the LVOT obstruction when stratifying patient anatomic suitability for TMVR.