Abstract
Much of the recent work attempting to simulate arterial flows has been motivated by attempts to elucidate the relationship between flow in the arteries and atherogenesis, and the focalization of plaque development. The aspect of the flow of most interest in this context was wall shear stresses, there being substantial evidence that the most susceptible sites are where shear stresses are low, or change rapidly in time or space [1]. These conditions are most likely to occur where there are sudden changes in flow geometry, and/or when the flow is unsteady. (For a recent review see [2].) We have studied flow in the carotid arterial bifurcation. Carrying out extensive simulations of the fully three-dimensional unsteady flow in realistic normal carotid bifurcation geometries allows us to identify the more dangerous sites for plaque development according to the above criteria. In the later stages of progression of atherosclerotic disease the relevant issues become vessel occlusion, embolic events, or plaque rupture, especially since recent clinical investigations have suggested that the danger posed by a particular plaque depends not only on the degree of occlusion but also on the so-called “vulnerability” of the plaque, the tendency of the plaque, depending on its composition, to fracture and rupture. To address these issues we have simulated flow in realistic severely stenotic carotid bifurcations toward the end of identifying critical features of plaque geometry and “risk factors” for plaque fracture and rupture.
