Aortic dissections occur from a violation of the intima, which allows blood to enter the media and dissect between the intimal and the adventitial layers. Common sites for tear include the ascending aorta and the region of the ligamentum arteriosum. The dissecting column of blood ruptures the intima and thus maintains a true and false lumen. The dissection may extend proximally, distally, or both. The patient's symptoms may cease abruptly when the dissection extends back through the intima; this may suggest a spontaneous cure. Alternatively blood may dissect through the adventitia and will nearly always be fatal.
Aortic dissection presents in a bimodal fashion. One group consists of younger patients with specific predisposing conditions. The predominant group is patients above age 50 with hypertension. Atherosclerosis is only a minor contributor to the pathogenesis of dissection.
Predisposing conditions for dissection include multiple forms of congenital heart disease, connective tissue disease, and pregnancy. Approximately 25 to 30% of patients with Marfan syndrome develop a dissection. Dissection may also be iatrogenically induced from aortic catherization or cardiac surgery.
Aortic dissections have been classified by two separate systems. The Stanford classification considers any involvement of the ascending aorta a type A dissection and dissections restricted to the descending aorta type B. DeBakey classified type I dissections as those that involve the ascending aorta, the arch, and the descending aorta. Type II involves only the ascending aorta and type III only the descending aorta.
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Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...