[Predictive value of albumin-to-fibrinogen ratio for acute kidney injury in infants undergoing ventricular septal defect repair with cardiopulmonary bypass].

Objective: To investigate the predictive value of albumin-to-fibrinogen ratio (AFR) for postoperative acute kidney injury (AKI) in infants with ventricular septal defect repair under cardiopulmonary bypass (CPB).

Methods: A retrospective analysis was conducted on infants diagnosed with ventricular septal defect in Anhui Children's Hospital from January 2019 to July 2023. The infants were divided into AKI group and non-AKI group according to whether AKI occurred in hospital after operation. Demographic data, preoperative data, intraoperative data, postoperative data and laboratory results during CPB were collected. Multivariate Logistic regression analysis was used to find the factors of AKI after ventricular septal defect repair with CPB. Receiver operator characteristic curve (ROC curve) was drawn to analyze the predictive value of AFR for postoperative AKI after ventricular septal defect repair with CPB.

Results: A total of 215 children were collected, including 28 in AKI group and 187 in non-AKI group. There were no significant differences in age, gender, body weight, height, history of pneumonia and history of chronic heart failure between the two groups, but the left ventricular ejection fraction (LVEF) in the AKI group was significantly lower than that in the non-AKI group (0.526±0.028 vs. 0.538±0.030, P = 0.048). The duration of CPB (minutes: 74.1±12.1 vs. 65.8±11.3, P < 0.001), aortic cross-clamping (minutes: 41.7±9.7 vs. 37.2±9.4, P = 0.021) and hypothermic circulation arrest (21.4% vs. 8.6%, P = 0.047) in AKI group were significantly higher than those in non-AKI group, but there were no significant differences in the proportion of ultrafiltration and urine volume between the two groups. The length of intensive care unit (ICU) stay in AKI group was significantly longer than that in non-AKI group (days: 5.3±2.0 vs. 4.0±1.7, P < 0.001), but there were no significant differences in duration of mechanical ventilation and the proportion of postoperative hypotension between the two groups. During CPB, the levels of blood glucose (mmol/L: 9.4±1.3 vs. 8.8±0.8, P < 0.001), blood lactic acid (mmol/L: 2.2±0.3 vs. 2.0±0.3, P = 0.015) and serum creatinine (μmol/L: 79.7±11.5 vs. 74.4±10.9, P = 0.018) in AKI group were significantly higher than those in non-AKI group, while the AFR was significantly lower than that in non-AKI group (8.5±1.3 vs. 10.2±1.6, P < 0.001), but there were no significant differences in the levels of hemoglobin, blood urea nitrogen, alanine aminotransferase and aspartate aminotransferase between the two groups during CPB. Multivariate Logistic regression showed that AFR was a protective factor for AKI after ventricular septal defect repair with CPB [odds ratio (OR) = 0.439, 95% confidence interval (95%CI) was 0.288-0.669, P < 0.001]. Blood glucose (OR = 2.133, 95%CI was 1.239-3.672, P = 0.006) and blood lactic acid (OR = 5.568, 95%CI was 1.102-28.149, P = 0.038) were risk factors for AKI after ventricular septal defect repair with CPB. ROC curve analysis showed that the area under the curve (AUC) of AFR in predicting AKI after ventricular septal defect repair with CPB was 0.804 (95%CI was 0.712-0.897, P < 0.001). When the optimal cut-off value was less than 9.05, the corresponding sensitivity was 75.0% and the specificity was 72.7%.

Conclusions: Low AFR (≤9.05) during CPB is an independent risk factor for AKI after ventricular septal defect repair with CPB. AFR during CPB has a high predictive value for postoperative AKI after ventricular septal defect repair with CPB.