Combination of Two Urinary Biomarkers Predicts Acute Kidney Injury After Adult Cardiac Surgery

摘要

Patient PopulationUrinary Biomarker MeasurementStatistical AnalysesResultsPatient Characteristics and Changes in Serum CreatinineUrinary L-FABP and NAG Levels in AKICombination of Urinary L-FABP and NAGUrinary L-type fatty acid-binding protein (L-FABP) has not been evaluated for adult post-cardiac surgery acute kidney injury (AKI) to date. This study was undertaken to evaluate a biomarker panel consisting of urinary L-FABP and N-acetyl-β-D-glucosaminidase (NAG), a more established urinary marker of kidney injury, for AKI diagnosis in adult post-cardiac surgery patients.MethodsThis study prospectively evaluated 77 adult patients who underwent cardiac surgery at 2 general hospitals. Urinary L-FABP and NAG were measured before surgery, at intensive care unit arrival after surgery (0 hours), 4, and 12 hours after arrival. The AKI was diagnosed by the Acute Kidney Injury Network criteria.ResultsOf 77 patients, 28 patients (36.4%) developed AKI after surgery. Urinary L-FABP and NAG were significantly increased. However, receiver operating characteristic (ROC) analysis revealed that the biomarkers' performance was statistically significant but limited for clinical translation (area under the curve of ROC [AUC-ROC] for L-FABP at 4 hours 0.72 and NAG 0.75). Urinary L-FABP showed high sensitivity and NAG detected AKI with high specificity. Therefore, we combined these 2 biomarkers, which revealed that this combination panel can detect AKI with higher accuracy than either biomarker measurement alone (AUC-ROC 0.81). Moreover, this biomarker panel improved AKI risk prediction significantly compared with predictions made using the clinical model alone.ConclusionsWhen urinary L-FABP and NAG are combined, they can detect AKI adequately, even in a heterogeneous population of adult post-cardiac surgery AKI. Combining 2 markers with different sensitivity and specificity presents a reasonable strategy to improve the diagnostic performance of biomarkers.Abbreviations and Acronyms: AKI (acute kidney injury), AUC (area under the curve), CKD (chronic kidney disease), CPB (cardiopulmonary bypass), GFR (glomerular filtration rate), IDI (incremental discrimination improvement), L-FABP (L-type fatty acid-binding protein), NAG (N-acetyl-β-D-glucosaminidase), NGAL (neutrophil gelatinase-associated lipocalin), NRI (net reclassification index), POD (postoperative day), ROC (receiver operating characteristics)CTSNet classification:25Acute kidney injury (AKI) is an extremely severe complication for patients who undergo cardiac surgery. Recently, Lassnigg and colleagues [