RESUMEN
Objective:To assess the value of urine heat-shock protein-70 (HSP-70) in the early diagnosis of acute kidney injury (AKI) after cardiac cardiopulmonary bypass (CPB).Methods:Patients with cardiopulmonary bypass from May 2018 to July 2018 in Henan Provincial People's Hospital were enrolled as subjects. Urine samples were collected before and after cardiopulmonary bypass at 0 h, 2 h, 4 h, 6 h, 8 h, 12 h, 24 h and 48 h. Patients were divided into AKI group and non-AKI group according to the Kidney Disease: Improving Global Outcomes Guide. Urinary HSP-70, tissue inhibitor of metalloproteinase-2 (TIMP-2) and insulin-like growth factor-binding protein 7 (IGFBP7) were detected by enzyme-linked immunosorbent assay (ELISA) and urine neutrophil gelatinase-associated lipocalin (NGAL) was determined by immunoturbidimetry. The receiver operating characteristic (ROC) curve was plotted to calculate the critical value, sensitivity and specificity of urine HSP-70, [TIMP-2]×[IGFBP7] and NGAL for the diagnosis of postoperative AKI after CPB.Results:A total of 45 patients were enrolled in the study. There were 24 cases in AKI group and 21 cases in non-AKI group. The level of urinary HSP-70, [TIMP-2]×[IGFBP7] and NGAL in AKI group were significantly higher than in the non-AKI group at each postoperative time point, with statistically significant differences (all P<0.05). The level of urinary HSP-70 in AKI group peaked at 2 h after CPB, which was significantly earlier than the peak time of urine [TIMP-2]×[IGFBP7] and urine NGAL (12 h after CBP and 4 h after CBP, respectively). Urinary HSP-70≥2.1 μg/L could predict postoperative AKI of CPB at 2 h after CPB, with the area under the curve ( AUC) of 1.00, the sensitivity of 100.0% and the specificity of 100.0%. Urinary [TIMP-2]×[IGFBP7]>19.1 μg 2/L 2 could predict postoperative AKI of CPB at 12 h after CPB with the AUC of 0.94, the sensitivity of 87.5%, and the specificity of 100.0%. Urinary NGAL>27.4 μg/L could predict postoperative AKI of CPB at 4 h after CPB with the AUC of 0.95, the sensitivity of 95.8%, and the specificity of 85.7%. The positive predictive value of urine HSP-70≥2.1 μg/L at 2 h after CPB was 100.0%, and the negative predictive value was 100.0%. Conclusions:The level of urinary HSP-70 increases earlier than that of urinary [TIMP-2]×[IGFBP7] and NGAL in patients with AKI after CPB. Clinical monitoring of urinary HSP-70 level contributes to early diagnosis of AKI.