Aneurysms are bulges filled with blood in the walls of blood vessels. The coronary arteries are the blood vessels that supply blood to the heart tissue. Aneurysms in the coronary arteries are rare. They could be present at birth; develop Inflammation of vessel walls from an immune system defect; or develop in association with atherosclerosis,which is where cholesterol builds up on the walls of the vessel. Kawasaki disease, which is an infection affecting young children, is another potential cause. Coronary catheterization, a procedure in which a plastic tube is inserted into the vessels for different reasons, is also another risk factor. These aneurysms are also often detected during coronary catheterizaitions. Coronary artery aneurysms can cause irregular flow of the blood through the coronary artery, and can be treated with medical management to prevent complications or surgery.