[Atheromatous aneurysms of the thoracic aorta]

Atheromatous aneurysms of the thoracic aorta are much less common than those of the abdominal aorta. Associated atherosclerosis of the coronary, cerebral and peripheral limb arteries is observed in 16, 10 and 11% of cases, respectively. Ultrasonography. CT scanning, and mostly MRI and digitised angiography provide very accurate morphological data. The natural history is dominated by the risk of rupture with a 3 year survival of 50% in aneurysms with a diameter superior to 5 cm. The surgical indication should be considered in cases of aneurysms with diameters over 5 cm after full carotid, coronary, respiratory and renal investigations. Surgery is simple in descending aortic aneurysms but more complicated in aneurysms of the transverse and descending aorta, especially in long lesions. Technical innovations have reduced the incidence of both cerebral complications after surgery of the aortic arch by improved cerebral protection and of medullary complications after surgery of the descending thoracic aorta, especially of thoraco-abdominal aneurysms, by better medullary protection against ischaemia during aortic clamping. The operative results have a mortality of: 3% for aneurysms of the ascending aorta: 10% for aneurysms of the aortic arch: 9% with a 15% risk of paraplegia, for long aneurysms of the descending thoracic aorta.