Investigating the right heart hemodynamics in the Tetralogy of Fallot: a computational study

Characterizing flow within the right heart (RH) is particularly challenging due to its complex geometries. However, gaining insight into RH fluid dynamics is of extreme diagnostic importance given the high prevalence of acquired and congenital heart diseases with impaired RH functionality. In this study, we present a comprehensive, patient-specific, image-based computational analysis of the hemodynamics of the RH in healthy and repaired-ToF (ToF) cases. From multi-series cine-MTRI, we reconstruct the geometry and motion of the patient's right atrium, ventricle, and pulmonary and tricuspid valves. For this purpose, we develop a novel and flexible reconstruction procedure that enables us, for the first time, to integrate fully patient-specific tricuspid valve dynamics into a computational model, enhancing the accuracy of our RH blood flow simulations. This work provides novel insight into the altered hemodynamics of repaired-ToF RH with severe pulmonary regurgitation and into the hemodynamics changes induced by the pulmonary valve replacement intervention. Modelling the whole RH enables us to understand the contribution of the superior and inferior vena cava inflows to the ventricular filling, as well as the impact of the impaired right atrial function on the ventricular diastole. We analyze the turbulent and transitional behaviour by including the Large-Eddies Simulation sigma model in our computational framework. This highlights how the contribution of the smallest scales in the dissipation of the turbulent energy changes among health and disease.