Causes

An aortic dissection is caused by a weakened area of the aorta's wall.

Aortic dissections are divided into two groups, depending on which part of the aorta is affected:

• Type A. This more common and dangerous type involves a tear in the part of the aorta where it exits the heart. The tear may also occur in the upper aorta (ascending aorta), which may extend into the abdomen.
• Type B. This type involves a tear in the lower aorta only (descending aorta), which may also extend into the abdomen.