CONVECTIVE MASS-TRANSFER AT THE CAROTID BIFURCATION

The convective conditions in regions of hemodynamic separation may pro duce uneven local mass transfer at the arterial wall which may lead to an atherogenic response. This study estimates the potential variation in local mass transfer of oxygen at the human carotid bifurcation und er steady flow conditions. The three dimensional separated how at the bifurcation was studied using a computational analysis of the basic co nservation equations of mass, momentum, and species. Mass transfer bet ween the blood and the wall was estimated throughout the sinus region for a condition where the concentration at the wall was constant. Flow separation at the carotid bifurcation created a complex concentration held. The mass transfer was five times lower along the outer wall of the carotid sinus than the artery wall immediately upstream or downstr eam of the sinus. The region of low mass transfer was similar to the r egion of low shear stress but not identical. This distribution of low mass transfer correlated strongly with intimal thickening as measured previously from human specimens. Quantitative differences in mass tran sfer at the arterial wall should not be discarded as an important mech anism by which hemodynamics influences atherogenesis at this site of c linical disease. (C) 1997 Elsevier Science Ltd.