A quantitative study of the localization of atherosclerotic lesions in the rabbit aorta.

A quantitative study of the size and location of early sudanophilic lesions has been carried out on the aortae of five rabbits. The atherosclerotic lesions were induced by feeding an average of 114 (+/- 3.7) egg yolks over an average period of 83 (+/- 1.7) days. The aortic lesions were visualuized by gross staining with Sudan III and measured by the polar coordinate method. The lesions were almost entirely around orifices: their size was directly proportional to the area of the associated ostium (P less than 0.005). The sudanophilic deposits were located downstream from the ostia in areas believed to experience high shear stresses. The area of the intercostal ostia increased as one proceeded down the thoracic aorta (P less than 0.005). A deviation from the distal distribution pattern was observed where local flow and shear stresses were disturbed. The coronary lesions completely surrounded the ostia, the coeliac lesions had significant proximal components and the left renal and inferior mesenteric lesions were skewed to the right. The study suggests that hemodynamic forces and particularly high shear stress is of considerable importance in both the initiation and localization of early atherosclerotic lesions.