Usefulness of plasma neutrophil gelatinase-associated lipocalin as an early marker of acute kidney injury after cardiopulmonary bypass in Korean cardiac patients: a prospective observational study.

OBJECTIVES: Development of acute kidney injury (AKI) after cardiopulmonary bypass (CPB) is relatively common and associated with increased mortality. Recently, plasma neutrophil gelatinase-associated lipocalin (NGAL) was used for the prediction of AKI. We evaluated the clinical usefulness of plasma NGAL.

DESIGN AND METHODS: One hundred twelve adult patients undergoing cardiovascular surgery with CPB were included. Blood samples were obtained at baseline, at intensive care unit (ICU) admission, and 24h after ICU admission. The development of AKI, which is defined as an increase in serum creatinine by more than 50% within 3 postoperative days, was monitored. NGAL levels were analyzed by a Biosite Triage meter (Alere Medical, USA). Diagnostic performance of NGAL was analyzed using the area under the receiver operating characteristic curve.

RESULTS: In AKI patients (n=13), plasma NGAL levels at ICU admission were significantly higher than those at baseline [177 (122-402) vs. 121 (74-158) ng/mL, median (interquartile range), p=0.028], whereas serum creatinine showed no significant change. The predictive value of NGAL at ICU admission was 0.812 [95% confidence interval (CI), 0.68 to 0.95] with a cut-off value of 168.5ng/mL (sensitivity, 61.5%; specificity, 88.9%). After the exclusion of 35 patients with preoperative decreased renal function, the predictive value was increased to 0.911 (95% CI, 0.82 to 1.00).

CONCLUSIONS: This study showed that plasma NGAL may serve as a useful biomarker for the early detection of AKI in adult patients following CPB.