Mass transport to walls of stenosed arteries: Variation with Reynolds number and blood flow separation

Abstract

Abnormalities in the exchange of substances between the arterial wall and the blood flowing within the lumen may occur when blood flow is disturbed near vessel constrictions, bends and branches. We have studied these effects using a computer simulation of mass transport to the wall, of a simple solute dissolved in the blood flowing through an axisymmetric constriction in a straight, cylindrical vessel with constant wall concentration. Over the complete nonturbulent range of Reynolds numbers, the results show three distinct mass transport patterns which are related to three distinctly different blood flow patterns. These occur at Reynolds numbers less than, equal to, or greater than that required for blood flow separation and vortex formation. With the last two flow patterns, there are regions of both enhanced and impaired mass flux and, surprisingly, these occur in close proximity. This analysis was applied to oxygen to determine if there could be an impairment in oxygen transport to the wall at the sites of blood flow disturbance. Our results may explain the apparent predilection of specific sites along the arterial tree for the initiation and progression of atherosclerosis.