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Abstract: SA-PO074

Preoperative Risk Assessment Improves Biomarker Detection for Predicting AKI After Cardiac Surgery

Session Information

Category: Acute Kidney Injury

  • 003 AKI: Clinical and Translational


  • Lee, Cheng chia, Chang Gung Memorial Hospital, Taoyuan, Taiwan
  • Chang, Chih-Hsiang, Chang Gung Memorial Hospital, Taoyuan, Taiwan
  • Yang, Chih-Wei, Chang Gung Memorial Hospital, Taoyuan, Taiwan

The major challenge in managing acute kidney injury (AKI) lies in making an early diagnosis. Although urinary neutrophil gelatinase-associated lipocalin (NGAL) has emerged as a promising biomarker for the early detection of kidney injury, previous studies of adult patients have reported only moderate discrimination. The age, creatinine, and ejection fraction (ACEF) score is a preoperative validated risk model for predicting AKI following cardiac surgery. It remains unknown whether combined preoperative risk assessment through ACEF scores followed by urinary NGAL is an optimal approach with improved predictive performance.


This prospective study was performed in a tertiary referral center in Taiwan between July 2014 and February 2015. A total of 177 consecutive patients who underwent cardiac surgery were enrolled. Clinical characteristics, prognostic model scores, and outcomes were assessed. The ACEF scores were calculated as age (years)/ejection fraction (%) + 1 (if creatinine > 2.0 mg/dL). NGAL were examined within 6 hours after cardiac surgery. Patients were stratified according to preoperative ACEF scores, and comparisons were made using the area under the receiver operator characteristic (AUROC) curve for the prediction of AKI.


A total of 45.8% (81/177) of the patients had AKI. Patients with ACEF scores ≥ 1.1 were older and more likely to have diabetes mellitus, myocardial infarction, peripheral arterial disease, and class III or IV heart failure. Urinary NGAL alone moderately predicted AKI, with an AUROC of 0.732. Risk stratification by ACEF scores ≥ 1.1 substantially improved the AUROC of urinary NGAL to 0.873 (95% confidence interval, 0.784–0.961; P < .001).


Risk stratification by preoperative ACEF scores ≥ 1.1, followed by postoperative urinary NGAL, provides more satisfactory risk discrimination than does urinary NGAL alone for the early detection of AKI after cardiac surgery. Future studies should investigate whether this strategy could improve the outcomes and cost-effectiveness of care in patients undergoing cardiac surgery.

Performance of NGAL in discriminating AKI, stratified by ACEF scores
PopulationAUROC (95% CI)P valueOptimal cut-off (ng/mL)Sensitivity (%)Specificity (%)PPV (%)NPV (%)
ACEF < 1.10.606 (0.492–0.720)0.071>45.161.561.550.568.5
ACEF ≥ 1.10.873 (0.784–0.961)<0.001>77.583.387.281.288.7
Total0.732 (0.656–0.808)<0.001>82.660.580.267.175.3


  • Government Support - Non-U.S.