RESUMEN
Neutrophil Gelatinase Associated Lipocalin [NGAL] is a new biomarker which can predict acute kidney injury [AKI] in critically ill patients. Usefulness of NGAL in the early diagnosis of all types of AKI is under question. We hypothesized NGAL is an early predictive biomarker of contrast-induced nephropathy [CIN]. In this process evaluation study, we enrolled 122 patients [Mean age 59.7 +/- 10.8 years] undergoing elective angiography/angioplasty with contrast media during April to September 2009. Serial urine samples were analyzed in a double-blind fashion by NGAL enzyme-linked immunosorbent assay. CIN was defined as a 25% increase in baseline serum creatinine. The prevalence of CIN was 30.3%. Significant elevations in urinary NGAL concentrations were noted within 12-h and 24-h after the procedure in patients with CIN. NGAL concentrations after 12 hours was 90.62 +/- 105.63 vs. 27.6 +/- 45.8 ng/ml in patients with and without CIN, respectively P=0.0001, and 79.78 +/- 117.7 vs. 30.92 +/- 52.84 ng/ml, 24 hours afterwards P=0.002. Some patients had AKI after five days of exposure rather than the second day [P=0.0001]. We found using a cut-off point of 8 ng/ml with a sensitivity, specificity, negative predictive value and area under the ROC curve 94%, 25%, 91% and 0.75 respectively are good for the prediction of CIN in 12-h urinary NGAL and a cut-off point of 5.5 ng/ml with respective values of 97%, 24%, 95% and 0.70 for 24-h urinary NGAL. Urine NGAL may represent a sensitive early biomarker of acute AKI after angiography/angioplasty. We recommend the routine measurement of NGAL in high risk patients receiving contrast agents