Hemodynamic Modeling for Mitral Regurgitation

Abstract

<h3>Purpose</h3> Mitral regurgitation (MR) is a serious valvular pathology that impacts over 2% of the total population. Despite evidence that MR poses potentially significant risks of RV dysfunction and failure, the risks of MR are mainly assessed based on left heart parameters, including the mitral regurgitant fraction (MRF) and effective regurgitant orifice area (EROA). To elucidate the links between MR and RV dysfunction, we propose a computational fluid dynamic (CFD) modeling pipeline aimed at providing a deeper understanding of the interplay between MR and RV function. <h3>Methods</h3> Dynamic CT data of a spatiotemporal motion of the patient's heart were segmented using a 3D U-Net based neural network. Meshed segmentations were propagated through time using IRTK non-rigid registration and volume preserving surface motion interpolation to recreate the motion of the patient's heart over the cardiac cycle. The 3D model was coupled to a closed loop 0D model that represents the remaining cardiovascular system and provides continuous feedback to the 3D model. This also allows the relationship between the complicated hemodynamics in the left heart and the state of the RV to be modeled. The functionality of the RV is prescribed by defining the stroke volume over the cardiac cycle. Mild, moderate, and severe MR was prescribed by defining the EROA's based on clinical parameters. <h3>Results</h3> We looked at how different MR jet areas (EROA) and RV functions pose risks to the cardiovascular system. Results from this study show that a high RV function reduces MRF at the expense of much higher right ventricle stroke work index (RVSWI) - which is strongly correlated with RV failure (Fig. 1). Variation in EROA has a lower impact on the RF and RVSWI than the RV functionality, but it does change the local hemodynamics (Fig. 2). <h3>Conclusion</h3> This process makes it possible to further understand the effect that MR has on right heart function. This is particularly important for patients who require a left ventricular assist device in which right heart failure, linked with MR, is a recognized complication.