Serum interleukin 6 levels as an early marker of acute kidney injury on children after cardiac surgery.

BACKGROUND: Cardiosurgical operations in cardiopulmonary bypass (CPB) constitute a risk of acute kidney injury (AKI). OBJECTIVES: The aim of the study was an assessment of AKI risk in children within the first 24 hours after CPB cardiac surgery, evaluating serum interleukin 6 (sIL6). MATERIAL AND METHODS: The study included 47 children with congenital heart disease operated in CPB. Blood samples were taken before the procedure (0 hour) as well as at 2, 6, 12, 18 and 24 hours after the operation. RESULTS: AKI was confirmed in 19 children. The mean sIL6 concentration in the AKI compared with non-AKI group was: 180.6 vs. 93.7; p = 0.0017. The maximum sIL6 in the AKI group was obtained at 2 hrs after CPB (350.36 pg/ml). Logistic regression analysis for AKI development depending on the value of sIL6 at 2 hrs after CPB proved that every rise of sIL6 by 100 pg/ml increased the chance of AKI development by 70% (p = 0.0161). With every circulatory arrest time prolongation by 10 minutes for a given sIL6 concentration, the chance of AKI development increased by 47% (p = 0.0407). AKI risk at 2 hrs after CPB, for a sIL6 cut-off point amounting to 185 pg/ml, increased more than 3-fold (AUROC - 68%). CONCLUSIONS: Determining sIL6 in children after cardiosurgical operations at 2 hrs after the procedure constitutes a good, yet not a perfect marker of AKI risk development. Nomograms of the constant risk values of AKI were worked out presenting the ranges of values in relation to serum IL6 concentrations and the child's body mass, age and the time of circulatory arrest.