Determination of Urinary Neutrophil Gelatinase-Associated Lipocalin (NGAL) Cut-off Level for Early Detection of Acute Kidney Injury in Thai Adult Patients Undergoing Open Cardiac Surgery

Background: Acute kidney injury (AKI) is a common complication in patients undergoing open cardiac surgery. Urinary neutrophil gelatinase-associated lipocalin (UNGAL) is an early marker of AKI, however, its predictive value in adult patients undergoing open cardiac surgery has never been investigated in Thailand. Objective: The present study aimed to determine the cut-off level of UNGAL for predicting AKI in adult patients undergoing open cardiac surgery and also to determine the risk factors for AKI development. Material and Method: In all, 130 patients at Rajavithi Hospital were prospectively enrolled during a six-month period. UNGAL was obtained at baseline before surgery, and at 0, 3, and 6 hours after surgery and assessed by ARCHITECT NGAL assay. Serum creatinine levels were measured at baseline before surgery simultaneously for the collection of UNGAL and then daily after surgery. AKI was defined as an increment in serum creatinine of >0.3 mg/dl within 48 hours according to the Acute Kidney Injury network (AKIN) criteria. Results: Forty-six patients (35.4%) developed AKI, and 80.4% of these patients had the onset of AKI within the first 6 hours after surgery. In this group, UNGAL increased significantly at 0, 3, and 6 hours after surgery compared with patients without AKI. UNGAL at 3 hours after surgery was the best time-point for predicting AKI. The cut-off value was >11.3 ng/ml with the sensitivity and specificity of 72% and 60%, respectively. By univariate analysis, older age, lower ejection fraction, impaired baseline renal function and longer cardiopulmonary bypass (CPB) time were clinical factors associated with AKI. However, by multivariate analysis, only lower ejection fraction and longer CPB time were associated with AKI. Conclusion: UNGAL level may be a useful marker for predicting AKI in Thai adult patients undergoing open cardiac surgery. Lower ejection fraction and longer CPB time were two major risk factors for AKI development. Keywords: Neutrophil gelatinase-associated lipocalin (NGAL), Cardiac surgery, Acute Kidney injury