Influences of mitral valve shape on transmitral hemodynamics before and after edge-to-edge repair: development of a reduced-order model

Transcatheter edge-to-edge repair (TEER) is an effective treatment for mitral valve regurgitation in patients with high surgical risk, but predicting the hemodynamic outcomes is challenging. Reduced-order models (ROMs) show promise for post-TEER hemodynamic outcome predictions, but personalization of the ROM equations is essential for accurate simulations of mitral valve blood flow rates and pressure gradients during both diastole and systolic regurgitation. While the mitral valve orifice area is a common parameter used for ROM personalization, other aspects of the mitral valve shape are usually not considered. In this in-silico study, we investigated the influences of mitral valve shape on transmitral hemodynamics using a combination of computational fluid dynamics (CFD) simulations and geometrical analyses. Mitral valves from ten TEER patients were analyzed at three valve states: early diastole (pre- and post-TEER) and systolic regurgitation (pre-TEER). The orifice-to-annulus area ratio and the orifice orientation were identified as key shape parameters impacting mitral valve hemodynamics. Based on these findings, we developed shape-based ROM equations that are personalized using routine echocardiographic data. The ROM estimates agreed well with CFD simulation results (mean relative differences <1 % and limits of agreements <13 % for both flow rates and pressure gradients). Application of the ROM equations to patient-specific data revealed distinct hemodynamic differences between the three valve states, aligning with expectations from both physiological and fluid dynamics perspectives. Our results suggest that incorporating mitral valve shape parameters into ROMs could improve the accuracy of patient-specific simulations, thus enhancing their potential for supporting TEER planning and predicting intervention outcomes.