Low wall shear stress contributes to atherosclerosis of the carotid arteryin hypertensive patients

Numerous ill vitro studies have indicated that low shear stress may contrib ute to intimal thickening and development of atherosclerosis, In the presen t study, we investigated wall shear stress in hypertensive patients and its relevance to atherosclerosis in the carotid arteries by means of a non-inv asive technique. Fifty-five hypertensive patients and 23 normotensive contr ols were investigated. Intima-media thickness, number of plaques, internal dimension and blood flow velocity of the carotid artery were evaluated. Wal l shear stress was calculated using the Poiseuillean parabolic model of vel ocity distribution as follows: shear stress=4Xblood viscosityXcentral line how velocity/internal dimension, Hypertensive patients showed increased int ima-media thickness and dilated common carotid arterial dimension relative to normotensive controls. There was no difference in blood viscosity betwee n the two groups. Both the mean shear stress and systolic peak shear stress were significantly lower in hypertensive patients than normotensive contro ls, Further, wall shear stress at both mean and peak velocity was significa ntly and negatively related to intima-media thickness and number of plaques in hypertensive patients, as well as in the total study population. These findings indicate that structural and functional alterations in the common carotid artery of hypertensive patients further precipitates atherosclerosi s through low shear stress.