WALL SHEAR-STRESS AND EARLY ATHEROSCLEROTIC LESIONS IN THE ABDOMINAL-AORTA IN YOUNG-ADULTS

Objectives: To study the correlation between wall shear stress and ear ly atherosclerotic lesions in the abdominal aorta. Design: Blinded his tomorphometric studies. Comparison with in vitro data. Materials: Abdo minal aortic haemodynamics were simulated in a realistic pulsatile paw model. Abdominal aortas from 10 young adults with no signs of atheros clerotic disease were obtained during autopsy. Methods: Quantitative w all shear stresses were measured at vest and exercise in one suprarena l and two infrarenal positions using laser Doppler anemometry. Intimal thickening indices were measured blindedly at the corresponding locat ions using histomorphometric methods, and compared to wall shear stres s variables using linear regression analysis. Results: Intimal thickne ss index increased significantly with age. Intimal thickness index tea s significantly lower in the suprarenal than the infrarenal aorta, and higher at the distal posterior vessel wall compared to the anterior w all. Intimal thickness index correlated significantly with mean, minim um and oscillating wall shear stresses measured at rest. Conclusion: I ntimal thickness in the undiseased abdominal aorta correlated signific antly with mean, minimum and oscillating wall shear stresses at rest m easured in a pulsatile flow model. No correlations were found with max imum shear stress parameters. Exercise changed the local wall shear st resses away from the characteristics associated with intimal thickness index.