[Ureteral obstruction secondary to aortofemoral bypass]

Hydroureteronephrosis is reported as a frequent late complication of aorto-femoral bypass grafts in patients with aorto-iliac obstruction. To define the actual incidence of this potentially critical complication, renal ultrasonography (US) was performed on 79 asymptomatic patients who had previously undergone aortic reconstruction, after a mean interval of 71.6 months. Unilateral hydronephrosis was found in 6 cases (7.6%). Dilatation was mild or moderate (grade I or II) in 4 cases, and severe (grade III) in 2. Ivp was performed in this selected group: hydronephrosis was mild in 3 patients with ureteral stenosis where the iliac limb of the graft crossed the ureter. In 2 cases nonfunctioning kidneys were demonstrated corresponding to severe sonographic hydronephrosis. These 2 patients underwent anterograde and retrograde pyelography, that showed the site and extent of the obstruction. One patient was a false positive because of obstruction of pyelo-ureteral junction. Even though X-rays showed high sensitivity and specificity in detecting this complication of aorto-femoral reconstruction, US is noninvasive and less expensive and does not require contrast medium. A routine pre- and post-operative ultrasound study is suggested in patients undergoing by-pass surgery to early recognise ureteral obstruction and to avoid irreversible renal damage.