Aortic dissection is a potentially life-threatening condition in which there is bleeding into and along the wall of the aorta, the major artery leaving the heart.
Aortic dissection most often occurs because of a tear or damage to the inner wall of the artery. This usually occurs in the thoracic (chest) portion of the aorta, but may also occur in the abdominal portion. The aorta has different branches through which blood flows. An aortic dissection is classified as type A or B depending on where it begins and ends. Type A begins in the first (ascending) part of the aorta and typically moves to another part of the chest. Type B begins in the last (descending) part of the aorta and moves down the abdomen.
When a tear occurs, it creates two channels: One in which blood continues to travel and another where blood remains still. As the aortic dissection grows bigger, the channel with non-traveling blood can get bigger and push on other branches of the aorta.
An aortic dissection may also involve abnormal widening or ballooning of the aorta (aneurysm).
