ANALYSIS OF SHEAR-STRESS AND HEMODYNAMIC FACTORS IN A MODEL OF CORONARY-ARTERY STENOSIS AND THROMBOSIS

Shear stress and alterations in blood flow within a stenosed artery pr omote platelet-dependent thrombosis. Using the Folts model of coronary thrombosis, we evaluated morphology, histology, and the hemodynamic p roperties of the stenosed vessel in 18 animals. The average stenosis c reated was 58 +/- 8%, with stenosed vessel diameters ranging from 0.08 4 to 0.159 cm. Histological examination of the stenosed vessel demonst rated that thrombi were composed primarily of platelets and formation occurred 1.0 mm downstream from the apex of the constriction, propagat ing distally. Peak shear stress occurred just upstream from the apex o f the stenosis and varied from 520 to 3,349 dyn/cm2. Only small differ ences in shear forces were noted when blood viscosity was calculated u sing Newtonian and non-Newtonian properties. In contrast, shear stress computed for Poiseuille flow with use of the stenosis diameter undere stimated the apical shear stress. Blood flow remained laminar within t he stenosis with a Reynolds number range of 292-534. Our data indicate that the geometry of the stenosis inflow region must be considered in the evaluation of platelet activation and thrombus formation within a stenosed artery.