Physiological Flow Studies in Exact-Replica Atherosclerotic Carotid Bifurcations

Abstract

Some results from a series of physiological flow experiments in a model of an atherosclerotic carotid bifurcation are presented. The flow model exactly replicates the lumen of the plaque excised intact from a patient with severe carotid atherosclerosis. Flow visualization (FV) and particle image velocimetry (PIV) are employed as the tools for this study. The complex internal geometry of the diseased artery combined with the pulsatile input flows gives rise to complex flow patterns. The flow fields are highly three-dimensional and chaotic with details varying from cycle to cycle. These flow patterns also include internal jets, three-dimensional shear layers, numerous separation/recirculation zones and stagnation lines. The vorticity and streamline maps confirm this complex and three-dimensional nature of the flow. Planar streamline maps show the three-dimensional flow by the multiple sources/sinks throughout the model. Wall shear stresses (WSS) are estimated to range form about −7 Pa to 34 Pa at the stenotic neck over time with the peak at peak systolic. These WSS also exhibit chaotic behavior during pulsatile flow cycles.