Dissection of the Aorta

DISSECTION of the aorta is the most common acute disease of the aorta. Without therapy, it is highly lethal. In the classic series of Hirst et al,162% of the patients were dead within seven days of the time of the onset of symptoms, and 93% were dead within a year. Few patients die instantaneously; the majority survive long enough for the diagnosis to be made. If the clinician recognizes dissection of the aorta, he now has available highly successful medical or surgical therapy. With appropriate therapy, the mortality of dissection is less than 20%.2 Recognition of aortic dissection is difficult because it is almost always confused with acute myocardial infarction. Pathophysiology The lesion that predisposes to dissection is cystic medial necrosis.3The cause of cystic medial necrosis is unknown. We do know that hypertension and Marfan's syndrome predispose to this lesion in the media of the