A Simulation Study of the Effects of Number and Location of MitraClips on Mitral Regurgitation

MitraClip (MC) is a device that is implanted on the mitral valve (MV) percutaneously to treat severe mitral regurgitation (MR). It is common practice to place the MCs at the site of the most significant MR jets identified by echocardiography. We used computational modeling to examine changes in MR after MC placement. Echocardiographic images from 29 patients with MR were analyzed to reconstruct geometries for finite element simulations and created fluid structure interaction models of the MV with deformable hyperelastic material, the left ventricle as the surrounding geometry, and blood flow. Blood flow was modelled with smoothed particle hydrodynamics. The number of blood particles on the atrial side of MV was used to estimate MR. MC placement was based on the MR jets (jet-based strategy using primary and secondary jets) and simulation models using various MCs locations. Computational modelling was able to quantitate reductions in MR after MC placement. Reduction in MR was related to the number of MCs used: 42% reduction with 1 MC, 62% with 2 MCs, and 88% with 3 MCs. Using 2 MCs did not always result in an MR reduction greater than with a single MC. In 31% (9 of 29) of patients, the jet-based strategy did not lead to maximum MR reduction. The majority of patients (89%) who did not have maximal MR reduction with the MC placement using the jet-based strategy, had wide jets, and/or had multiple jets. Subject-specific simulation models may be helpful to identify optimal locations for MC placement in patients with MR.