Aortic dissecting aneurysms: causative factors in 204 subjects.

The pathogenesis of dissecting aneurysms of the aorta is controversial. We reviewed the records of the 204 patients with aortic dissecting aneurysms who underwent autopsy at the John Hopkins Hospital, Baltimore, from 1889 to the present and compared them with age-, race-, and sex-matched controls. The results show that hypertension, Marfan's syndrome, and traumatic, atherosclerotic, or inflammatory injuries of the aortic media are factors associated with dissection. The gross and histologic findings and associated circumstances suggest that most spontaneous aortic dissections originate from tears of the inner layers of the aorta followed by intramural cleavage. In other patients, rupture of the intra-aortic course of branch arteries or vasa vasorum may lead to dissection. Thus, no pathogenetic mechanism is common to all aortic dissections.