Aortoiliac occlusive disease occurs when your iliac arteries become narrowed or blocked. The aorta, your body’s main artery, splits into branches at about the level of your belly button. These branches are called the iliac arteries. The iliac arteries go through your pelvis into your legs, where they divide into many smaller arteries that run down to your toes. Aortoiliac disease is considered a type of peripheral arterial disease (PAD) because it affects arteries, which are blood vessels that carry blood away from your heart to your limbs.
Your arteries are normally smooth and unobstructed on the inside, but as you age, a sticky substance called plaque can build up in the walls of your arteries. Plaque is made up of cholesterol, calcium, and fibrous tissue. As more plaque builds up, it causes your arteries to narrow and stiffen. This process is called atherosclerosis, or hardening of the arteries. Eventually, enough plaque builds up to interfere with blood flow in your iliac arteries or leg arteries. Physicians call this aortoiliac occlusive disease because it involves the aortoiliac arteries.
When your iliac arteries narrow or become blocked, your legs may not receive the blood and oxygen they need. This lack of oxygen is called ischemia and it can cause pain. In severe cases, sores or gangrene can develop, which can result in losing a limb. However, these developments are uncommon unless the process is not treated and is allowed to progress.