Hemodynamics in the pulmonary bifurcation in relation to adults with congenital heart disease : effect of branching angle and origin

Boumpouli, Maria and Danton, Mark and Gourlay, Terry and Kazakidi, Asimina; Owen, Roger and de Borst, Rene and Reese, Jason and Pearce, Chris, eds. (2018) Hemodynamics in the pulmonary bifurcation in relation to adults with congenital heart disease : effect of branching angle and origin. In: Proceedings of the 6th European Conference on Computational Mechanics. International Centre for Numerical Methods in Engineering, CIMNE, GBR, pp. 1833-1844. ISBN 9788494731167

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    Pulmonary regurgitation is the most common, clinically-important, complication that affects an increasing population of adult patients with congenital heart disease, primarily with repaired tetralogy of Fallot. Without intervention, the condition can lead to abnormal dilatation of the right ventricle, arrhythmias, heart failure, or death. Pulmonary valve replacement (PVR) is a frequent reoperation, the clinical decision for which is currently relying on symptoms, including arrhythmias and measures of the right ventricular volume. However, there is no common consensus on the reliability of these criteria and further studies are needed for an accurate and timely assessment for PVR treatment. The overall objective of this work is to hemodynamically characterise the pulmonary bifurcation in adult patients with congenital heart disease, pre- and post-operatively, and help establish novel metrics for a more accurate assessment for PVR, contributing to better surgical planning. In this study, we present preliminary computational fluid dynamic results in simplified models of the pulmonary trunk and its branches, in order to investigate the effect of the bifurcation angle on the flow. Physiological vessel dimensions and boundary conditions were used, in both symmetric and asymmetric geometries, and blood flow was simulated by solving the incompressible Navier-Stokes equations. Increase of the branching angle altered the flow development within the bifurcation, and had evident effects on the flow separation downstream of the junction. Shear stresses on the wall connecting the two artery branches were found, for the first time, dependent also on the origin of each branch, having a greater effect on the left pulmonary artery. These results demonstrate the impact of geometry on velocity, pressure, and wall shear stresses in the pulmonary bifurcation and contribute to a better understanding of the underlying flow mechanisms. Future studies will involve 3D reconstruction of patient-specific models of the pulmonary bifurcation, obtained from MRI images of adult patients with repaired tetralogy of Fallot, that need or have undergone pulmonary valve replacement.