Urinary Albumin:Creatinine Ratio (ACR) and the Prediction of Postoperative Complications After Abdominal Aortic Aneurysm Repair

Abstract

IntroductionOpen repair of abdominal aortic aneurysm (AAA) requires aortic clamping. This results in an ischaemia-reperfusion injury (IRI) which can lead to the development of the systemic inflammatory response syndrome (SIRS) and multiple organ failure (MOF). We investigated the use of urinary albumin:creatinine ratio (ACR) as a simple predictor of the development of complications (SIRS) postoperatively. MethodsForty-four patients undergoing elective infrarenal AAA repair and 10 control patients undergoing major abdominal surgery had fresh urine samples taken before, immediately after and 24h after the procedure. Urinary ACR was calculated on all samples, and daily SIRS scores were calculated for all patients postoperatively. Systemic interleukin-6 (IL-6) levels were measured intraoperatively to measure the cytokine response to surgery. ResultsAAA patients demonstrated a characteristic pattern of ACR levels during the three time points, with a significant increase in the ACR immediately postoperatively and with normalisation by 24h (P<0.001 Wilcoxon signed ranks test). In comparison, control patients did not demonstrate any changes in their ACR (P=0.45 Wilcoxon signed ranks test) suggesting the increased ACR in AAA patients to occur as a result of IRI. ACR did not correlate with the development of SIRS postoperatively or with the systemic IL-6 response. ConclusionsInfrarenal AAA repair is associated with a temporary and reversible renal injury. ACR could not, however, be used as a predictor of complications postoperatively.