Blood Flow Pattern in Bending Coronaries in Coronary Artery Bypass Grafts

This study investigates the effect of coronary bending in a 3D model of a Coronary Artery Bypass Graft (CABG), while considering Fluid-Structure Interaction (FSI). The coronary had an axisymmetric stenosis with lumen reduction of 65% and the arterial wall was modeled as linear elastic. The blood was considered a Newtonian fluid and pulsatile pressure was applied as the boundary condition for the two inlets and the outlet. Results revealed that the bending led to a lower level of coronary flows, but higher graft flows. Compared to the straight coronary model, Shear Stress (SS) in the outer wall of the stenosis in the curved model increased by 9%. For both models, there was a recirculation area downstream of the stenosis in which Wall Shear Stress (WSS) was low, which might put this region at high risk of restenosis. For the bending model, this area expanded in the inner wall while contracting in the outer wall. For both models, wall effective stress increased near the anastomosis area, especially at the heel of the graft, while the bending model did not alter this stress along both vessels.