Cardiac perfusion coupled with a structured coronary network tree

Sufficient myocardial perfusion plays a pivotal role in maintaining normal pump function. However the development of a comprehensive myocardial perfusion model remains particularly challenging as it requires the incorporation of complex interactions across different spatial scales and physical domains. In this study, we couple a coronary blood flow model to our previous work on a poroelastic immersed finite element framework for myocardial perfusion in a left ventricle (LV) heart. The coronary flow in the epicardial vessels is described by a 1-D flow model, and the intramural vessels are modelled as a structural tree-based vascular bed. The intramyocardial pressure resulting from myocardial contraction is further imposed on the coronary vessel wall. We first benchmark this coupled myocardial perfusion and coronary flow in a healthy heart. The systolic impediment phenomenon of the coronary flow can be reproduced with this coupled model, and the wall volume change is around 13mL, which is consistent with literature-reported values. We further study cardiac perfusion under coronary network rarefaction, arterial wall stiffening and ventricular wall stiffening. Our results suggest that both vessel rarefaction and a stiffer arterial wall can directly impede flow through the coronaries leading to perfusion deficiency, and LV wall stiffening will impair heart pump function significantly but with a minor drop in coronary flow rate. It is expected that such a coupled myocardial perfusion and coronary flow model will have the potential to deepen our understanding of myocardial dysfunction due to perfusion deficiency.