Family history Aneurysms are serious because of the possibility they will burst, causing life-threatening internal bleeding. Approximately 15,000 Americans die from a ruptured aortic aneurysm each year. In addition, aneurysms often house small blood clots. These clots may break loose and block a blood vessel elsewhere in your body, causing impaired function, pain or potentially life-threatening problems. Aneurysms can develop in any blood vessel, such as in the artery of your knee or the small arteries in your eye or brain.
Most aneurysms occur in large blood vessels, especially the aorta.
The aorta is your body's largest artery. It runs down your center, delivering blood from your heart and lungs to the rest of your body. A small aneurysm might double this diameter. Some aneurysms span 3 or more inches in diameter. Not all aneurysms reach a point of rupture.