Blood flow dynamics, atherosclerosis and bypass graft failure

Atherosclerosis occurs at reproducible sites in the arterial tree and intimal proliferation that leads to bypass gl aft occlusion also show a well-defined focal distribution These observations have led to the hypothesis that local blood flow conditions, especially low or fluctuating shear stresses, are important in the development of both disorders. Basic research using both cell culture and animal models has revealed that endothelial cell biology is very sensitive to local shear stresses and rapid progress is being made in characterizing how endothelial cells transduce shear stress. Endothelial sensitivity to shear stress affects control of hemostasis, leukocyte adherence and transmigration, growth factor production, vasomotor responses, endothelial repair and arterial wall remodeling, all of which can be expected to influence development of vascular pathologies. Also, substantial progress has been made in characterizing complex local hemodynamics at relevant arterial sites, however, further progress is needed in this area, as well as in the extrapolation of advances in basic vascular biology to human vascular disease. (C) 1997, Elsevier Science Inc.