The effect of aortic coarctation on shear stresses and flow fields through the rabbit aortic bifurcation

Atherosclerosis is associated with areas in the vasculature that are exposed to low, oscillating hemodynamic shear stresses such as the outer wall of arterial bifurcations. Understanding mechanisms that contribute to this association requires study of the effects of shear stress on the expression of biological markers of atherosclerosis. We have used computational fluid dynamics to investigate the shear stress distribution through the aortic bifurcation of a normal rabbit and a rabbit with a surgically placed partial aortic stenosis. Transit time ultrasonic flow probes were used to determine the volumetric flow rates and casting materials were used to determine the geometry of the bifurcation. Optical imaging techniques were utilized to create a geometric model of the artery, and a finite volume computational fluid dynamics program was employed to determine the flow field and wall shear stresses. The aortic bifurcation in the rabbit with the aortic coarctation is exposed to lower shear stresses that oscillate for longer periods during the cardiac cycle. This methodology has been developed in order to manipulate various hemodynamic parameters and determine their effects on flow fields and wall shear stresses for future correlation with biological data