Abstract 9471: Temporal Relationship and Predictive Value of Urinary Acute Kidney Injury Biomarkers After Pediatric Cardiopulmonary Bypass
Introduction Acute kidney injury (AKI) occurs commonly after cardiopulmonary bypass (CPB). Serum creatinine (SCr) is an inadequate marker for AKI. Rapidly detectable AKI biomarkers could allow early intervention and improve outcome. We evaluated the temporal pattern and predictive value (alone and in combination) of 4 urinary AKI biomarkers: neutrophil gelatinase-associated lipocalin (NGAL), interleukin-18 (IL-18), liver fatty-acid binding protein (L-FABP) and kidney injury molecule-1 (KIM-1) for CPB associated AKI.
Methods Urine samples were obtained prospectively before and at intervals after CPB in 220 patients. AKI was defined as a ≥50% SCr rise within 48h of CPB. The temporal pattern of biomarker elevation was established and biomarker elevations were correlated with AKI severity and clinical outcomes. Logistic regression was used to assess AKI predictors. Biomarker predictive abilities were evaluated by AUC, net reclassification improvement (NRI) and integrated discrimination improvement (IDI).
Results AKI occurred in 27% of patients. NGAL increased in AKI patients at 2h after CPB and remained elevated at all timepoints (Figure). IL-18 and L-FABP increased at 6h and KIM-1 increased at 12h. Biomarker elevations correlated with disease severity and clinical outcomes, and improved AKI prediction above a clinical model. At 2h addition of NGAL increased the AUC from 0.74 to 0.85 (p<0.0001). At 6h NGAL, IL-18 and L-FABP each improved the AUC from 0.72 to 0.91, 0.84 and 0.77, respectively (all p<0.05). At 12h, all biomarkers improved the AUC. The added predictive ability of the biomarkers was supported by NRI and IDI. Biomarker combinations further improved AKI prediction.
Conclusion Urine NGAL, IL-18, L-FABP and KIM-1 are sequential predictive AKI biomarkers and correlate with clinical outcomes after pediatric CPB. These biomarkers, particularly in combination, may be useful in establishing AKI timing and application of appropriately timed therapy.
- © 2011 by American Heart Association, Inc.