Pathogenesis of Dissecting Aneurysm

Abstract

A group of 35 cases of dissecting aneurysm was studied both clinically and pathologically, in order to evaluate the role of alterations in the aortic wall in the pathogenesis of dissecting aneurysm. It was concluded that the commonly observed dilatation and hypertension promoted the initial tear by increasing the tension on the intima of the aorta. The usual cause of the aortic dilatation in this study was severe atherosclerosis; a much smaller group revealed an idiopathic medial degeneration; muscular lesions were regarded either as insignificant or as a result of the dissection. Although in many instances the initial perforation occurred through an atherosclerotic plaque, dissection proceeded readily through histologically normal media. Accordingly, it was concluded that the two histologic lesions encountered produced their effects largely by provoking dilatation of the aorta rather than by promoting propagation of the dissection.