DefinitionAortic dissection is a potentially life-threatening condition in which there is bleeding into and along the wall of the aorta, the major artery carrying blood out of the heart.Alternative NamesAortic aneurysm - dissectingCauses, incidence, and risk factorsWhen it leaves the heart, the aorta first moves up through the chest toward the head (the ascending aorta). It then bends or arches, and finally moves down through the chest and abdomen (the descending aorta).Aortic dissection most often occurs because of a tear or damage to the inner wall of the aorta.This usually occurs in the thoracic (chest) portion of the artery, but may also occur in the abdominal portion.An aortic dissection is classified as type A or B depending on where it begins and ends.Type A begins in the first (asc