3D Printing and Computational Modeling for the Evaluation of LVOT obstruction in Transcatheter Mitral Valve Replacement

Transcatheter mitral valve replacement (TMVR) is an emerging alternative treatment for those patients not qualified for surgery. However, TMVR can determine an obstruction of the left ventricular outflow tract (namely, neo-LVOT) induced by the transcatheter heart valve (THV) displacing the native mitral valve leaflet towards the myocardial wall. This condition can lead to haemodynamic impairment and ultimately patient death. We sought to predict the neo-LVOT obstruction by first developing patient-specific simulations of the THV deployment and then comparing predictions with post-TMVR diagnostic images and 3D printed human models. Using pre-TMVR computed-tomography (CT) imaging, patient-specific anatomies of two patients were reconstructed and then meshed with ABAQUS/Explicit solver. The latter was used to simulate the crimping and deployment of SAPIEN 3 THV (Edwards Lifesciences, Irvine, CA) and then simulate the cardiac beating. The neo-LVOT cross sectional area was then computed. For both patients, rigid heart models were printed with SLS rapid prototyping technology while the SAPIEN 3 device was printed with flexible resin to manually positioning the device in the human host. Numerical predictions and 3D printed model measurements of neo-LVOT area agreed well with those obtained by post-TMVR CT imaging. Both computational modelling and 3D printing revealed a comprehensive assessment of the TMVR feasibility, which is not readily conferred by conventional CT imaging. Particularly, the realistic printed models could become an efficient and indispensable tool to help the heart team visualizing the LVOT obstruction to anatomical scale, in a life-size replica of patient-specific cardiac anatomy.