Arterial Fluid Mechanics and Biological Response

To better understand the response of the arterial wall to the adjacent blood flow, corresponding hemodynamic and histomorphometric data are obtained at multiple sites in human arteries. The hemodynamic data are obtained by perfusing realistically compliant flow-through casts of vascular segments with physiologically realistic pulsatile flows and measuring near-wall velocities by laser Doppler velocimetry. The hemodynamic and histologic data in combination suggest that the thickening response of the innermost layer of the vessel wall, which may precede atherosclerosis at the site, varies with time and wall shear: at early times, sites exposed to relatively high and unidirectional shears are thicker, while at later times, their thickness is exceeded by that at sites exposed to relatively low or oscillatory shear forces. A biologically plausible mathematical model of the thickening process supports the hypothesis that this behavior can be the consequence of multiple shear-dependent processes in the vessel wall.