Background: Worsening of renal function (WRF) in acute heart failure (AHF) strongly predicts adverse clinical outcome. Plasma neutrophil gelatinase-associated lipocalin (NGAL) has been proposed as an earlier biomarker of tubular damage, but important methodological issues remain unsolved, particularly in AHF.
Methods and results: In 30 consecutive patients admitted for AHF, 108 serum NGAL (Alere system) measurements were performed at entry and in the first days of recovery, and reproducibility within the same blood samples was very high (r = 0.98). NGAL at entry was related to kidney function [r = 0.51 vs. creatinine (Cr) and r = -0.49 vs. estimated glomerular filtration rate (eGFR), both P < 0.001], and weakly with hemoglobin (r = -0.36, P < 0.05) and C-reactive protein (CRP) (r = 0.26, P < 0.05). During hospitalization, WRF occurred in 26.7% of the patients. Baseline NGAL was only slightly higher in patients who developed WRF as compared to those who did not (151 ± 90 vs. 119 ± 75 ng/ml, NS), but it increased significantly in the following days, always preceding WRF occurrence (max. previous 24 h, average 95%, range 25-200%). The area under the Receiver Operating Characteristic (ROC) curve (AUC-ROC) was 0.69 for pathological NGAL at entry and 0.91 for delta NGAL changes during the first days.
Conclusions: In patients with AHF, serum NGAL measurement is highly reproducible and at entry it is related to baseline Cr and eGFR, but does not predict WRF during subsequent hospitalization. On the contrary, serial measurements of NGAL in the first days of hospitalization can accurately predict WRF.