Microrheology and clinical medicine: unravelling some problems related to thrombosis

Abstract

Atherosclerotic lesions and thrombus formation occur preferentially around bifurcations, curved segments and stenoses where flow is likely disturbed and vortices may form. Hence we have studied the detailed flow patterns, and the effects of the associated fluid mechanical stresses existing at such sites on the aggregation and wall adhesion of corpuscles using microrheological techniques and a newly developed method for making large arteries and veins transparent. The annular vortex formed downstream of a model stenosis was found to provide favorable conditions for spontaneous aggregation and enhanced adhesion of platelets onto the vessel wall. Similar flow patterns were observed in the pockets of venous valves where venous thrombi are suspected to originate. Formation of standing vortices was also found in dog aortas at each branching site and in the sinus of the human internal-external carotid artery bifurcation under physiological flow conditions.