Overview Abdominal aortic aneurysm An abdominal aortic aneurysm is an enlarged area in the lower part of the major vessel that supplies blood to the body (aorta). The aorta runs from your heart through the center of your chest and abdomen. The aorta is the largest blood vessel in the body, so a ruptured abdominal aortic aneurysm can cause life-threatening bleeding. Depending on the size of the aneurysm and how fast it's growing, treatment varies from watchful waiting to emergency surgery. Symptoms Abdominal aortic aneurysms often grow slowly without symptoms, making them difficult to detect. Some aneurysms never rupture. Many start small and stay small; others expand over time, some quickly. If you have an enlarging abdominal aortic aneurysm, you might notice: Deep, constant pain in your abdomen or on the side of your abdomen Back pain A pulse near your bellybutton When to see a doctor If you have pain, especially if pain is sudden and seve...