To define the relevance of treating renal artery aneurysms (RAAs) surgically. Most prior definitions of the clinical, pathologic, and management features of RAAs have evolved from anecdotal reports. Controversy surrounding this clinical entity continues. A retrospective review was undertaken of 168 patients (107 women, 61 men) with 252 RAAs encountered over 35 years at the University of Michigan Hospital. Aneurysms were solitary in 115 patients and multiple in 53 patients. Bilateral RAAs occurred in 32 patients. Associated diseases included hypertension (73%), renal artery fibrodysplasia (34%), systemic atherosclerosis (25%), and extrarenal aneurysms (6.5%). Most RAAs were saccular (79%) and noncalcified (63%). The main renal artery bifurcation was the most common site of aneurysms (60%). RAAs were often asymptomatic (55%), with a diagnosis made most often during arteriographic study for suspected renovascular hypertension (42%). Surgery was performed in 121 patients (average RAA size 1.5 cm), including 14 patients undergoing unilateral repair with contralateral RAA observation. The remaining 47 patients (average RAA size 1.3 cm) were not treated surgically. Operations included aneurysmectomy and angioplastic renal artery closure or segmental renal artery reimplantation, aneurysmectomy and renal artery bypass, and planned nephrectomy for unreconstructable renal arteries or advanced parenchymal disease. Eight patients underwent unplanned nephrectomy, being considered a technical failure of surgical therapy. Dialysis-dependent renal failure occurred in one patient. There were no perioperative deaths. Late follow-up (average 91 months) was available in 145 patients (86%). All but two arterial reconstructions remained clinically patent. Secondary renal artery procedures included percutaneous angioplasty, branch embolization, graft thrombectomy, and repeat bypass for late aneurysmal change of a vein conduit. Among 40 patients with clearly documented preoperative and postoperative blood pressure measurements, 60% had a significant decline in blood pressure after surgery while taking fewer antihypertensive medications. Late RAA rupture did not occur in the nonoperative patients, but no lessening of this group's hypertension was noted. Surgical therapy of RAAs in properly selected patients provides excellent long-term clinical outcomes and is often associated with decreased blood pressure.
