An aneurysm is a weakening in the wall of an artery, leading to a bulge or “ballooning.” The aorta is the body's main artery, delivering blood from the heart, though the chest (thoracic cavity) down to the abdomen and on to the rest of the body. Unless a thoracic aortic aneurysm has burst, which is a medical emergency and often fatal, it frequently causes no symptoms and may only be detected as part of imaging done for another reason. Because the risk of rupture is high, it is important to keep a very close eye on the aneurysm – watchful waiting – or replace the bulging section before it tears or ruptures. See more about Thoracic Aortic Aneurysm repair treatment.