Neutrophil gelatinase-associated lipocalin as early predictor of acute kidney injury after cardiac surgery in adults with chronic kidney failure.

Abstract

To assess the utility of neutrophil gelatinase-associated lipocalin (NGAL) as an early marker of acute kidney injury (AKI) occurring after cardiac surgery in patients with prior chronic kidney failure. Patients with preoperative creatinine clearance 60 mL • min(-1) • 1.73 m(-2) or less according to the Cockcroft-Gault formula and scheduled to undergo cardiac surgery were eligible for inclusion. The AKI was defined as an increase in plasma creatinine greater than 50% over preoperative values. Threshold values of NGAL predictive of AKI were determined using receiver operating characteristic curve analysis, and predictive value of NGAL for AKI was evaluated by logistic regression. Over a 1-year inclusion period, 166 patients were included. At 6 hours post-surgery, hypertension, occurrence of at least 1 postoperative complication, and NGAL greater than 155 ng/mL were shown to be independent predictors of AKI. NGAL greater than 155 ng/mL at 6 hours was associated with an odds ratio for risk of postoperative AKI of 7.1 [2.7 to 18]. On average, diagnosis of postoperative AKI was made 20 hours earlier using NGAL at 6 hours post-surgery as compared with a diagnosis based on a 50% increase in creatinine over baseline. The threshold for NGAL of 155 ng/mL at 6 hours had a sensitivity of 79% and specificity of 58% for the diagnosis of AKI. Earlier diagnosis of AKI post-surgery based on NGAL assessment makes it possible to initiate appropriate therapy at an earlier stage in this high-risk patient population.