A Study of Local Hydrodynamics in a 90°Branched Vessel with Extreme Pulsatile Flows

To validate the pathologoical flow condition as the etiology of site-specific athero sclerosis, computer simulation and analysis are presented. Two extreme pulsatile flows, as have been measured in human femoral arteries, are used to numerically simulate in-vivo blood flow. The pulse with a steep temporal velocity gradient is assigned as “steep” pulse whereas the one with a lesser slope is called “less-steep” pulse. The effect of the extreme two pulses on the injury of endothelial cells in a 90° femoral artery of human is investigated by calculating flow parameters including instantaneous wall shear stresses. At the proximal and the distal branch apex, the oscillating wall shear stresses calculated from the ‘steep’ pulse cycle are found to be substantially greater than those from the ‘less-steep’ one. In contrast, for a straight artery, insignificant changes in flow parameters are observed for the extreme two pulses. It is evident from the calculated local wall shear stress that pathological changes can occur in the intima cells of the branch arterial wall and less likely in the straight arterial wall. An alteration of the pulsatile flow condition from a ‘steep’ to a ‘less-steep’ pulse, as may be achieved by pharmaceutical, chemical, or mechanical means, may be one of the possible ways to reduce the risk, thus slow the progression of or cause regression of arterial diseases, such as heart attack and stroke.