Our results demonstrate that common carotid artery wall shear stress measurement in vivo is reproducible. It inversely relates to intima-media thickness, age, systolic blood pressure, and body mass index. These findings confirm in vivo the role of shear stress in intima-media thickening.

The present results demonstrate that the atherosclerotic involvement of carotid arteries is usually asymmetrical and that wall shear stress is lower in the carotid arteries where plaques are present than in plaque-free arteries. These findings provide in vivo evidence for a strong association between shear stress and atherosclerotic lesions.

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The present findings suggest that TyG-Index is better associated with carotid atherosclerosis than HOMA-IR.

Abstract-The localization of atherosclerotic lesions is influenced by hemodynamic factors, namely, shear stress and tensive forces. The present study investigated the relationships between shear stress and circumferential wall tension and between these hemodynamic factors and the intima-media thickness (IMT) of the common carotid artery in healthy men. Fifty-eight subjects were studied. Shear stress was calculated as blood viscosityϫblood velocity/internal diameter. Circumferential wall tension was calculated as blood pressureϫinternal radius. Blood velocity, internal diameter, and IMT were measured by high-resolution echo-Doppler. Mean shear stress was 12.6Ϯ3.3 dynes/cm 2 (meanϮSD; range, 4.8 to 20.4) and was inversely related with age, blood pressure, and body mass index (BMI). Mean circumferential wall tension was 3.4Ϯ0.6ϫ10 4 dynes/cm (range 2.4 to 5.6) and was directly associated with age and BMI. IMT was inversely associated with shear stress (rϭ0.55, PϽ0.0001) and directly associated with circumferential wall tension (rϭ0.43, PϽ0.0001). Shear stress and circumferential wall tension were inversely correlated (rϭ0.66, PϽ0.0001). In multiple regression analysis, shear stress and (marginally) cholesterol were independently associated with IMT, whereas circumferential wall tension, age, and BMI were not. These findings confirm that common carotid shear stress varies among healthy individuals and decreases as age, blood pressure, and BMI increase. Our findings also demonstrate that circumferential wall tension is directly associated with wall thickness, age, and BMI and that shear stress is associated with common carotid IMT independent of other hemodynamic, clinical, or biochemical factors. (Hypertension. 1999;34:217-221.) Key Words: carotid arteries Ⅲ atherosclerosis Ⅲ stress, mechanical Ⅲ tensile stress Ⅲ tunica media A therosclerosis is a systemic disease, caused or favored by systemic risk factors, that localizes in particular regions of the arterial tree, probably through interaction with local predisposing factors. 1-2 Among the predisposing factors, the hemodynamic forces (shear stress and tensile stress) generated by flowing blood are of utmost importance. [3][4][5][6] Shear stress is the frictional force that acts tangentially to the endothelial surface. Tensile stress is the circumferential wall tension divided by wall thickness, and it acts perpendicularly to the arterial wall and results from the extensional (dilating) effect of blood pressure on the vessel. These hemodynamic forces also influence the vessel wall structure and development and contribute to the regulation of vascular tone. 5,[7][8][9][10][11] In vitro and in vivo experiments have demonstrated that vessels tend to maintain constant shear stress in response to flow changes. [12][13][14] We have previously demonstrated that common carotid artery shear stress in healthy men in vivo decreases with increasing age, blood pressure, and body mass index (BMI) and that low shear stress values are associated with intima-media thickening, an ech...