Background: Studies have identified hemodynamic shear stress as an important\ndeterminant of endothelial function and atherosclerosis. In this study, we assess the\ninfluences of hemodynamic shear stress on carotid plaques.\nMethods: Carotid stenosis phantoms with three severity (30, 50, 70%) were made\nfrom 10% polyvinyl alcohol (PVA) cryogel. The phantoms were placed in a pulsatile flow\nloop with the same systolic/diastolic phase (35/65) and inlet flow rate (16 L/h). Ultrasonic\nparticle imaging velocimetry (Echo PIV) and computational fluid dynamics (CFD)\nwere used to calculate the velocity profile and shear stress distribution in the carotid\nstenosis phantoms. Inlet/outlet boundary conditions used in CFD were extracted from\nEcho PIV experiments to make sure that the results were comparable.\nResults: Echo PIV and CFD results showed that velocity was largest in 70% than those\nin 30 and 50% at peak systole. Echo PIV results indicated that shear stress was larger\nin the upper wall and the surface of plaque than in the center of vessel. CFD results\ndemonstrated that wall shear stress in the upstream was larger than in downstream of\nplaque. There was no significant difference in average velocity obtained by CFD and\nEcho PIV in 30% (p = 0.25). Velocities measured by CFD in 50% (93.01 cm/s) and in 70%\n(115.07 cm/s) were larger than those by Echo PIV in 50% (60.26 �± 5.36 cm/s) and in\n70% (89.11 �± 7.21 cm/s).\nConclusions: The results suggested that Echo PIV and CFD could obtain hemodynamic\nshear stress on carotid plaques. Higher WSS occurred in narrower arteries, and\nthe shoulder of plaque bore higher WSS than in bottom part.
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