Changes in the In-vivo Functional State of the Mitral Valve in MitraClip Repair

Abstract

Objective: In this study, our focus is on the MitraClip procedure (Abbott Inc.), which is a minimally invasive surgical repair procedure to correct ischemic mitral valve regurgitation (IMR). While initial short-term outcomes have been encouraging, the long-term efficacy of this procedure, as well as patient-specific guidelines for optimization, remain unknown. The overall objective will be to develop a rapid and accurate simulation pipeline to predict and quantitatively assess the efficacy and longevity of the MitraClip procedure for individual patients using only pre-surgical and related population-based data. Methods: Clinical, real-time three-dimensional echocardiography (rt-3DE) images of patients’ mitral valves (MV) were segmented by a neural network (NN)-based approach to produce high-fidelity spline representations, which were integrated using isogeometric analysis into our custom finite element solver. This solver incorporated previous plasticity material models of the MV, in addition to measured changes in MV boundary conditions. We then simulated leaflet strains before and after the procedure and at three- and six-month follow up intervals, ultimately using only pre-surgical images. Results: Results to date to investigate the response of the MV to the MitraClip demonstrated an increase of radial strain and a decrease of circumferential strain in the posterior leaflets of the MV (Figure). Furthermore, stress concentrations were observed in both the circumferential and radial directions. Conclusions: The MitraClip clearly induced major alterations in MV leaflet strain and stress behaviors. This work confirms that such minimally invasive procedures dramatically alter the MV functional behaviors. This may lead to the underlying reasons long-term MV remodeling occurs in response to the observed stress concentrations, possibly leading to limited repair durability.