[Aneurysms of the renal artery]

A retrospective study of the patients operated on for renal artery aneurysm by a single surgeon during a 30-year period was undertaken. The author's experience amounts to 123 patients of whom 74 were females (60%) and 49 males (40%). The average age of the patients was 42.8 years. Preoperative investigations included usual tests of renal function, radiological investigations (fig. 4 and 5) and especially renal arteriography and study of the repercussions of arterial hypertension when present. In most cases (90%) these aneurysms were of fibrodysplastic origin. Acquired or postoperative aneurysms accounted for only 10% of cases. Dysplastic aneurysms are usually saccular with a fibrous neck and are located at or near an arterial bifurcation (fig. 1); they may have a very thin wall that explains the possible occurrence of rupture; intrasaccular thrombosis is very rare and so are embolies in the kidneys. Associated lesions are present in about two thirds of the patients (table I) and require a complete evaluation before surgery: lesions of the renal artery (segmental stenosis or diffuse fibromuscular hyperplasia) are the most frequent (fig. 2 and 3); other arteries either in the abdomen (aorta, splenic) or in distant territories (carotid) may also exhibit pathologic changes, particularly aneurysms; lesions of the kidney(s) and/or of the urinary tract may also be observed. In 80% of patients, the aneurysms were discovered on angiography performed because of arterial hypertension. But 20% of the patients were strictly normotensive. On account of bilateral repairs, 128 operations were performed: 17 nephrectomies and 111 vascular reconstructions. The main indication for nephrectomy was severely damaged kidneys. Vascular repair is the ideal treatment and various techniques may be used depending on anatomical arrangement of the vessels (table II). Ex situ surgery was performed in 29% of patients. Use of an arterial substitute is optional; when it appears necessary, arterial autografts are always preferable because they do not undergo late degenerative changes with time. The morbidity of surgical treatment is low. Evolution of arterial blood pressure after surgery leads to think that aneurysms of the renal artery cannot be held responsible for arterial hypertension: whenever a stenosis of the renal artery is associated, hypertension is of renovascular origin and is constantly cured or improved after surgery; in other patients, arterial hypertension remains unchanged after repair of the aneurysm, suggesting that hypertension is essential and simply coexists with the aneurysm without relationships of cause and effect between them. Surgery prevents the occurrence of ruptures as well and gives long term satisfactory anatomical results (fig. 6). Surgery is indicated in most cases and especially in young women (because of the risk of rupture during pregnancy) and in aneurysms exceeding 2 cm in diameter.