ABSTRACT
Objective:To evaluate the value of combined measurement of urinary insulin-like growth factor-binding protein 7 (IGFBP7) and urinary metalloproteinase inhibitor-2 (TIMP-2) in the early diagnosis and prognosis of cardiac surgery-associated acute kidney injury (CSA-AKI).Methods:From March 2018 to June 2018, cardiac surgery patients admitted to the cardiac macrovascular surgery department of the First Affiliated Hospital of Nanjing Medical University were prospectively included, and the blood creatinine was monitored to observe the presence of acute kidney injury (AKI). The prognostic information of the patients was collected, including in-hospital dialysis, in-hospital death, complete recovery of kidney function at discharge, death in one year after surgery, and progression to chronic kidney disease. The levels of urine IGFBP7 and TIMP-2 at 6 h, 24 h and 48 h after cardiac surgery were detected by enzyme linked immunosorbent assay (ELISA), and the urine creatinine (Cr) was also measured. Moreover, receiver operating characteristic curves (ROC) were plotted and the areas under the curves ( AUC) were calculated to evaluate the predictive value and prognostic value of urinary [TIMP-2]·[IGFBP7] (T*I for short) and urine T*I/urine Cr 2 in CSA-AKI. Results:A total of 74 patients with age of (58.43±10.91) years old and 47 males, were enrolled in this study, of which 24 cases (32.4%) had AKI and 10 cases (13.5%) had stage 2-3 AKI. Compared with the non-AKI group, the AKI group had significantly higher levels of urine T*I levels at 6 h and 24 h (both P<0.05). The AUC of T*I at 24 h predicting for AKI was 0.71(95% CI 0.59-0.81, P=0.001, cutoff value 0.020, sensitivity 79.2%, specificity 56.0%), while the AUC for stage 2-3 AKI was 0.85 (95% CI 0.75-0.92, P<0.001, cutoff value 0.083, sensitivity 70.0%, specificity 90.6%). Urinary T*I normalized for urinary creatinine excretion did not show better predictive value. In addition, of T*I at 24 h predicting for poor hospitalization outcome, renal recovery, and one year postoperative death, the AUC was 0.82(95% CI 0.71-0.90, P=0.001), 0.80(95% CI 0.66-0.86, P<0.001), and 0.81(95% CI 0.70-0.89, P=0.047), respectively. Conclusion:The combined detection of TIMP-2 and IGFBP7 in urine is expected to be a biomarker for early diagnosis of CSA-AKI and has certain clinical value in predicting the prognosis of CSA-AKI.