Rapid Detection of Acute Kidney Injury by Urinary Neutrophil Gelatinase-Associated Lipocalin in Patients Undergoing Cardiopulmonary Bypass

Abstract

OBJECTIVE: Acute kidney injury (AKI) is common following cardiopulmonary bypass (CPB). The aim of this study is to determine the accuracy of urinary Neutrophil Gelatinase-Associated Lipocalin (NGAL) levels following cardiac surgery to establish the severity of renal impairment as compared to serum creatinine levels.

METHODS: A total number of 28 patients undergoing elective cardiopulmonary bypass were included. Diagnostic criteria of AKI was estabilished in case of a percentage increase in the serum creatinine concentration of >50%. Serum creatinine levels were recorded in the preoperative period before induction and postoperative period in 24, 48 and 72. hours. Urinary NGAL measurement was performed before induction and in the 4th postoperative hour. The duration of CPB surgery, hospital stay and cross-clamp time were recorded.

RESULTS: Based on AKI criteria, subjects were grouped into AKI (n=11) and no AKI (n=19). Postoperative urinary NGAL levels were found significantly higher in group with AKI (11.8 ng mL-1 vs 104.0 ng mL-1, p=0.003). In AKI Group, CPB time bypass (111.9 min vs 82.7 min) and cross-clamp time (76.9 min vs 59.1 min) were significantly higher. A cutoff of 25.5 ng mL-1 yielded sensitivity of 81.82% and specifity of 94.12% at postoperative 4th hour with AUC of 0.947 for predication of AKI.

CONCLUSION: Urine NGAL rised significantly much earlier as compared to serum creatinine levels in the early postoperative period. Although larger case series are needed, we are in the opinion that urinary NGAL measurement may be used as an early clinical marker of AKI following CPB.