Abdominal aortic aneurysm. Frontal coloured X-ray of a 60 year old patient with an abdominal aortic aneurysm (AAA). The aorta (centre) is the main artery of the body. It runs from the heart through the abdomen, before branching into the two iliac arteries that serve the legs. The patient has previously had a stent (blue) placed in his aorta to treat a narrowing of the arteries (stenosis). However, due to weakening by high blood pressure an aneurysm (blood-filled dilation) has formed within the stent. If left untreated aneurysms, which are most common in men over 65 years of age, rupture and are often fatal. Treatment is with repair or removal of the vessel.