what causes an aortic aneurysm?
 1 Atherosclerosis, or hardening of the arteries, which weakens arterial walls. 2 Hypertension (high blood pressure). 3 Local injury to the artery. 4 Congenital abnormality. 5 Aging. 6 Syphilis used to be a common cause of thoracic aneurysms, but it is no longer as common. 