Proximal propagation of aortic thrombus with resultant impaired renal perfusion has been considered a significant risk of untreated infrarenal aortic occlusion. To investigate this question, we studied 52 patients surviving 1 year or more after surgical interruption of the infrarenal aorta in the course of treatment of aortic graft infection. Blood pressure, renal function, and renal artery anatomy were studied before and after aortic interruption. Preoperatively, 20 patients (38.4%) had treated hypertension, and 11 (21.2%) had impaired renal function (creatinine greater than 1.3 mg/dl). In 46 patients (88.4%) with angiography before aortic interruption, 31 (67.4%) had normal renal arteries, whereas 15 (32.6%) demonstrated renal artery stenosis of less than or equal to 50% (N = 10) or greater than 50% (N = 9). Concomitant renal revascularization (N = 3) or nephrectomy (N = 1) were rare. All patients were monitored after surgery for a mean period of 39.2 months. Thirty-three (63.5%) remain alive and well; 19 (36.5%) have died of causes not related (N = 15) or indirectly related (N = 4) to the original graft infection. Forty-eight patients (92.3%) had late assessment of their blood pressure (N = 44, mean follow-up of 31.0 months) and/or renal function (creatinine) (N = 42, mean follow-up of 26.1 months). Follow-up aortography in 21 patients (40.4%, mean interval of 27.7 months) demonstrated no instance of suprarenal propagation of aortic thrombus. During follow-up 41 patients (78.8%) had no change in either their blood pressure or serum creatinine. Seven patients (13.5%) developed worsening hypertension (N = 3) or a rising creatinine (N = 4).(ABSTRACT TRUNCATED AT 250 WORDS)