The chronic inhibition of angiotensin-converting enzyme impairs postoperative renal function

Postoperative renal impairment can increase postoperative mortality and mor bidity. We sought to identify preoperative risk factors responsible for pos toperative renal impairment in patients undergoing aortic surgery. This pro spective study included 249 patients admitted for aortic surgery. Preoperat ive and postoperative glomerular filtration rates (GFRs) were assessed with pre- and postoperative creatinine clearance measurements. Postoperative re nal impairment was defined as a 20% decrease in GFR between Day 0 (before s urgery) and Day 7 +/- 1 day (after surgery). Preoperative and intraoperativ e variables considered as potentially responsible for postoperative renal i mpairment were tested. Chronic treatment with angiotensin-converting enzyme inhibitors (ACEIs) was the only factor significantly associated with posto perative renal impairment (odds ratio [95% confidence interval] = 2.01 [1.0 5-3.83]). Chronic preoperative ACEI treatment is significantly associated w ith postoperative renal impairment. Inhibition of renal compensatory mechan isms caused by renin angiotensin system blockade might be responsible for t he observed decrease in renal function in patients chronically treated with ACEIs undergoing aortic surgery. However, age and preoperative renal dysfu nction were not associated with a postoperative decrease in GFR, but they w ere associated with a postoperative creatinine clearance < 60 mL/min.