An aortic aneurysm is a weakened area causing a bulge in the aorta - one of the body's largest blood vessels that carries blood from the heart to rest of the body. Aneurysms can develop throughout the length of the aorta. Abdominal aortic aneurysms (AAA) develop in the aorta passing through the abdomen and thoracic aortic aneurysms (TAA) in the aorta through the chest. Aneurysms can lead to rupture or dissection.
Because the aorta carries so much of the body's blood, a ruptured aortic aneurysm can cause life-threatening internal bleeding.
Aortic dissection occurs when there is a separation within the wall of the aorta, most commonly because of a tear or damage to the aorta's inner layer. A tear creates a split (dissection) between the inner and middle layer of the aorta, which can further lead to sudden blockage of critical branches of the aorta or a rupture. This often requires emergency surgery. Dissection of the aortic wall causes it to weaken and can lead to an aneurysm forming.