Modelling and numerical simulations of the Cardioband procedure for mitral valve regurgitation repair

The study reported in this dissertation is designed to characterize the Cardioband trascatheter annuloplasty procedure used in the repair of mitral regurgitation. A full in silico approach was considered to develop a simulative workflow to evaluate the outcomes of the Cardioband procedure in reducing mitral regurgitation in patient-specific cases. First, the mechanical behaviour of the Cardioband device was analysed through a physically based schematization of its components. The analytical formulation of this process and its numerical implementation to simulate the entire Cardioband process was achieved. Two simulation methods integrating clinical image processing and the finite element method were presented. The first method, called hybrid, was based on coupling equations modelling the equilibrium of forces and the geometric coherence of the device components with finite element equations relating to the behaviour of the cardiac structures. The latter, called full-fem, was based on the full finite element formulation of both the device and the surrounding structures. The routines were validated by simulating the clinical procedure on five different patient cases and comparing the numerical results with clinical data. Once the in-silico method was validated, the second step concerned the study of the effects of the Cardioband implant morphology on the outcomes of the procedure. Four different configurations were defined based on the implant size and the deployment strategy. The performance of the device customizability were evaluated by presenting the results. In the final step, a computational method based on the finite element approach was presented to investigate the effects of the Cardioband procedure on the dynamics of the regurgitant mitral valve. In particular, two types of simulations were defined, starting from an image-based modelling of the mitral apparatus. The first simulation was designed to reproduce the behaviour of the regurgitant mitral valve before Cardioband activation, while in the second simulation the valve is subjected to device activation and the loads resulting from the subsequent cardiac cycle. The two simulations were compared to evaluate the changes in mitral valve behaviour induced by the procedure.