An aneurysm is a localized abnormal widening of the blood vessel due to a weakening of the wall. They can be clinically silent and not cause any symptoms but nonetheless be potentially dangerous and rupture if they increase to a certain size. Thoracic aortic aneurysms can be treated by the cardiothoracic surgeon through an open chest operation or endovascular approach. The operation involves the insertion of an artificial graft into the abnormal blood vessel to cover the diseased section either directly (open operation) or percutaneously with a balloon and stent through a blood vessel in the leg (endovascular approach).