Aortic aneurysms may develop due to an aortic dissection, which is typically associated with high blood pressure.

An aortic dissection occurs when blood flow forces the layers of the wall of the aorta apart, which weakens the aorta. The separation can extend from the thoracic aorta through the entire aorta and block arteries to the legs, arms, kidneys, brain, spinal cord, and other areas.