Natural history and management of renal artery aneurysms in a single tertiary referral center.

OBJECTIVE: Although renal artery aneurysms (RAAs) are uncommon, several large reports have been published indicating their benign natural history. The objective of our study was to review our single-center experience managing this disease entity.

METHODS: A retrospective review of the Yale radiologic database from January 1999 to December 2016 was performed. Only patients with RAA and a computed tomography scan of the abdomen were selected for review. Demographics of the patients, aneurysm characteristics, management, postoperative complications, and follow-up data were collected.

RESULTS: There were 241 patients with 259 RAAs identified, with a mean age of 69 years (range, 35-100 years); 147 were female (61%). On computed tomography, aneurysms were solitary and right sided in 224 (86%) and 159 (61%), respectively; 64 (27%) patients had aneurysms elsewhere. The breakdown of RAAs by location was as follows: renal bifurcation in 84 (32%), renal pelvis in 77 (30%), distal renal artery in 58 (22%), mid renal artery in 34 (13%), and proximal renal artery in 6 (2%). Five patients had symptoms that were attributed to the RAA and underwent operative repair; all others were observed without an operation. Symptoms in the operative repair group included flank pain in four and uncontrolled hypertension in one. The mean overall diameter of the RAAs was 1.22 ± 0.49 cm. The diameter of operatively repaired and observed RAAs was 1.84 ± 0.55 cm and 1.21 ± 0.48 cm, respectively (P = .002). Operative repair included four coil embolizations and one open resection. There were no renal function changes in any of these patients after operation and no other complications. Mean follow-up was 41 ± 35 months for patients in the group that was observed; 18 of these RAAs were >2 cm, and none ruptured. On multivariable regression analysis, female sex (P = .0001), smoking history (P = .00007), left-sided RAA (P = .03), and main renal artery location (P = .03) were inversely related to growth, whereas a history of hypertension was directly related to growth rate (P = .01). The mean growth rate for RAAs was 0.017 ± 0.052 cm/y.

CONCLUSIONS: RAAs tend to have a benign natural history. Although previous reports have not identified any factors that contribute to RAA growth, we observed that RAA location, sex, smoking history, and hypertension may have an impact on growth rates. No ruptures were observed. Operative repair at our institution was rare, with no morbidity or mortality. Observation of RAAs over time seems feasible in the asymptomatic patient with a small RAA.