Low wall shear stress in carotid arteries in subjects with left ventricular hypertrophy

Left ventricular hypertrophy (LVH) is an independent risk factor for cardio vascular complications including atherosclerosis. The close linkage between LVH and carotid atherosclerosis has been the focus of much research. Howev er, the underlying mechanism linking the two conditions is not fully unders tood. Low wall shear stress contributes to intimal thickening and atheroscl erosis development as a local mechanism. In the present study, we investiga ted the relationship between wall shear stress and LVH in subjects with ris k factors for atherosclerosis. Eighty subjects with at least one risk factor for atherosclerosis; ie, hype rtension, diabetes mellitus, hyperlipidemia, or smoking, were enrolled. Int imal-medial thickness (IMT), number of plaques, internal dimensions, and bl ood flow velocity in the common carotid artery were evaluated. Wall shear s tress was calculated using a Poiseuillean parabolic model of velocity distr ibution: shear stress = 4 x blood viscosity x central flow velocity/interna l dimension. Subjects were divided into two groups; LVH(-) (n = 36) and LVH (+) (n = 44), according to their left ventricular mass index (LVTVI). Mean sheer stress and systolic peak shear stress were significantly lower i n subjects with LVH compared with subjects without LVH. Furthermore, mean s hear stress (r = -0.42, P < .0001) and peak shear stress (r = -0.31, P < 0. 01) were significantly inversely related to LVMI. Stepwise regression analy sis revealed that wall shear stress independently correlated with LVMI as w ell as IMT. These results indicate that low shear stress could function as a local factor in the development of atherosclerosis in subjects with LVH. (C) 2000 American Journal of Hypertension, Ltd.