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

UNLABELLED: Postoperative renal impairment can increase postoperative mortality and morbidity. We sought to identify preoperative risk factors responsible for postoperative renal impairment in patients undergoing aortic surgery. This prospective study included 249 patients admitted for aortic surgery. Preoperative and postoperative glomerular filtration rates (GFRs) were assessed with pre- and postoperative creatinine clearance measurements. Postoperative renal impairment was defined as a 20% decrease in GFR between Day 0 (before surgery) and Day 7 +/-1 day (after surgery). Preoperative and intraoperative variables considered as potentially responsible for postoperative renal impairment were tested. Chronic treatment with angiotensin-converting enzyme inhibitors (ACEIs) was the only factor significantly associated with postoperative renal impairment (odds ratio [95% confidence interval] = 2.01 [1.05-3.83]). Chronic preoperative ACEI treatment is significantly associated with postoperative renal impairment. Inhibition of renal compensatory mechanisms caused by renin angiotensin system blockade might be responsible for the observed decrease in renal function in patients chronically treated with ACEIs undergoing aortic surgery. However, age and preoperative renal dysfunction were not associated with a postoperative decrease in GFR, but they were associated with a postoperative creatinine clearance <60 mL/min. IMPLICATIONS: The aim of this study was to identify preoperative risk factors responsible for postoperative renal impairment in vascular surgery. Chronic angiotensin-converting enzyme inhibitor treatment was the only factor significantly associated with postoperative renal impairment. Inhibition of renal compensatory mechanisms caused by renin angiotensin system blockade might be responsible for the observed decreased renal function.