Neutrophil Gelatinase-Associated Lipocalin and Contrast-Induced Acute Kidney Injury.

BACKGROUND Neutrophil gelatinase-associated lipocalin (NGAL) is an early marker of acute kidney injury (AKI). METHODS AND RESULTS Urine NGAL and serum NGAL (sNGAL) were assessed at 2, 6, 24, and 48 hours after contrast media (CM) exposure in 458 high-risk patients (development set). Optimal thresholds in predicting contrast-induced AKI (serum creatinine [sCr] increase ≥0.3 mg/dL at 48 hours after CM administration) were identified. Major adverse events (MAE; death, dialysis, nonfatal myocardial infarction, sustained kidney injury, and myocardial revascularization) at 1 year were assessed. In the development set, optimal thresholds for contrast-induced AKI occurred at 6 hours for both urine NGAL (≥20 ng/mL; 97% negative predictive value and 27% positive predictive value) and sNGAL (≥179 ng/mL; 93% negative predictive value and 20% positive predictive value). Furthermore, sNGAL ≥179 ng/mL at 6 hours was an independent predictor of 1-year MAE. 1-year MAE occurred in 27/198 patients (13.5%) with sNGAL <179 ng/mL and sCr <0.3 mg/dL, in 57/193 (29.5%) patients with only sNGAL ≥179 ng/mL, and in 37/67 (55%) patients with sCr ≥0.3 mg/dL. In additional 253 patients (validation set), no patient with urine NGAL <20 ng/mL or sNGAL <179 ng/mL at 6 hours developed contrast-induced AKI. Furthermore, 6/68 (9%) patients with sNGAL <179 ng/mL and sCr increase <0.3 mg/dL had 1-year MAE versus 17/57 (30%) patients with sNGAL ≥179 ng/mL and sCr increase <0.3 mg/dL and 8/16 (50%) patients with sCr increase ≥0.3 mg/dL. CONCLUSIONS Urine NGAL <20 ng/mL and sNGAL <179 ng/mL at 6 hours are reliable markers for ruling out contrast-induced AKI. sNGAL ≥179 ng/mL at 6 hours predicts 1-year MAE. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT01098032.