Finite element analysis of MitraClip procedure on a patient-specific model with functional mitral regurgitation.

Mitral valve (MV) repair with the MitraClip device has been shown to reduce mitral regurgitation severity and improve clinical outcomes in symptomatic patients at high surgical risk. MitraClip was recently approved in the US for the treatment of functional mitral regurgitation (FMR), which significantly expands the number of patients that can be treated with this device. This study aims to quantify the morphologic changes and evaluate the biomechanical interaction between the MitraClip device and the mitral apparatus of a real patient case with FMR using computational modeling. MitraClip procedures using a central and a lateral clip were simulated in a validated MV-left ventricle finite element (FE) model with severe MR. The patient-specific model integrated detailed geometries of the left ventricle, mitral leaflets and chordae, incorporated age- and gender-matched nonlinear hyperelastic human material properties, and accounted for chordae tethering forces. Central and lateral positioning gave similar biomechanical outcomes resulting in an improved but incomplete MV coaptation. Antero-posterior distance, annulus area, valve opening orifice area, and regurgitant orifice area decreased by up to 26%, 19%, 48% and 63% when compared to the pre-clip model, respectively. Anterior and posterior leaflet peak stresses increased by up to 64% and 62% after clip placement, respectively, and were located at the region of clip grasp. Similarly, anterior and posterior leaflet peak strains increased by up to 20% and 10%, respectively. FE modeling, as used here, can be a powerful tool to examine the complex MitraClip-host biomechanical interaction.