Objective To explore the risk factors for early acute kidney injury (AKI) after lung transplantation and the predictive values of serum heart-type fatty acid binding protein 3 (H-FABP) and milk fat globule epidermal growth factor 8 protein (MFG-E8) levels.

Methods A total of 92 patients with lung transplantation in the hospital were selected and divided into AKI group (n=62) and non-AKI group (n=30) according to the occurrence of AKI within 7 days after surgery. The clinical data of the two groups were compared. Multivariate Logistic regression analysis was used to screen independent risk factors. The receiver operating characteristic (ROC) curve was used to analyze the predictive value of serum H-FABP and MFG-E8 alone and their combination, and bootstrap resampling (1 000 times) was used to verify the stability of the model.

Results The preoperative creatinine, intraoperative blood transfusion volume, and intraoperative urine volume in the AKI group were (58.52±14.02) μmol/L, 1 500.00 (1 000.00, 2 050.00) mL, and (320.50±85.22) mL respectively, which were all significantly higher than (51.75±13.39) μmol/L, 1 000.00 (700.00, 1 250.00) mL and (182.10±50.41) mL in the non-AKI group (P < 0.05). The proportions of patients with pulmonary hypertension, postoperative extracorporeal membrane oxygenation (ECMO) ≥ 2 days, and the use of ≥ 5 potentially nephrotoxic drugs in the AKI group were 70.97%, 45.16% and 63.33% respectively, which were all significantly higher than 50.00%, 23.33% and 23.33% in the non-AKI group (P < 0.05). The serum H-FABP level in the AKI group was (24.12±3.09) ng/mL, which was significantly higher than (12.19±2.93) ng/mL in the non-AKI group (P < 0.05); the MFG-E8 level in the AKI group was (64.82±18.84) pg/mL, which was significantly lower than (141.60±31.65) pg/mL in the non-AKI group (P < 0.05). Multivariate Logistic regression analysis showed that pulmonary hypertension, postoperative ECMO≥2 days, elevated preoperative creatinine, the use of ≥5 potentially nephrotoxic drugs, and increased intraoperative urine volume were independent risk factors for early AKI after lung transplantation (P < 0.05). The areas under the curve (AUCs) for the prediction by serum H-FABP, MFG-E8 alone and in combination were 0.764, 0.801, and 0.929, respectively. The combined prediction had a sensitivity of 90.32% and a specificity of 83.33%, showing the best performance (Z=4.002, 3.751, P < 0.05). After verification by the bootstrap method, the bias-corrected AUC of the model was 0.912(95%CI, 0.835 to 0.948), indicating good stability of the model prediction.

Conclusion Pulmonary hypertension, postoperative ECMO≥2 days, elevated preoperative creatinine, the use of ≥ 5 potentially nephrotoxic drugs, and increased intraoperative urine volume are independent risk factors for early AKI after lung transplantation. Serum H-FABP and MFG-E8 provide complementary information from the perspectives of injury and protection, respectively. Combined detection may improve early warning ability and provide a reference for early clinical intervention.