Hemodialysis before percutaneous renal biopsy on postoperative bleeding complications in patients with acute kidney injury

Objective To evaluate whether hemodialysis before percutaneous renal biopsy (PRB) reduces the risk of bleeding complications in patients with acute kidney injury (AKI). Methods This study was a cohort observational study. Patients who were diagnosed as AKI and received PRB in Nanfang Hospital of Southern Medical University from January 2015 to December 2018 were included in the study. Patients were divided into preoperative dialysis group and preoperative non-dialysis group according to whether PRB patients received hemodialysis treatment. According to whether perirenal hematoma occurred after the operation, the patients were divided into the groups with and without the perirenal hematoma. The baseline clinical data of AKI stage, hemoglobin, coagulation function and renal pathological changes before PRB, and perirenal hemorrhage complications after operation, including the size of perirenal hematoma within 24 hours, gross hematuria, low back pain, decreased hemoglobin value and interventional treatment (such as interventional surgery, blood transfusion, etc) in the two groups were compared. The logistic regression model was used to analyze the risk factors of perirenal hematoma after PRB. Results Ninety patients with AKI were enrolled in this study, including 41 in the preoperative dialysis group and 49 in the preoperative non-dialysis group. The proportion of patients AKI with stage 2-3 in the preoperative dialysis group was significantly higher than that in preoperative non-dialysis group (100.0% vs 75.5%, P<0.001). There were no significant differences in coagulation function indexes and platelet counts between the two groups. Renal ultrasound within 24 hours after PRB showed that there were no significant differences in the incidence of postoperative perirenal hematoma (56.1% vs 63.3%, P=0.489), the incidence of postoperative perirenal large size hematoma (≥5 cm, 26.1% vs 22.6%, P=0.766), and the magnitude of the decrease in hemoglobin (3.7% vs 1.2%, P=0.505) between the preoperative dialysis group and the preoperative non-dialysis group. No blood transfusion, arteriovenous fistula, renal vascular intervention or surgery, and no hospital death occurred in the two groups. The renal pathological manifestations of the patients with and without perirenal hematoma were mainly acute tubular necrosis (ATN) and there were no significant differences between the patients with and without perirenal hematoma in indicators such as age, gender, body mass index, diabetes percentage, hypertension percentage, AKI staging, preoperative dialysis or not, serum creatinine, blood urea nitrogen, hemoglobin, platelet count and renal pathological types. After adjusting for indicators such as preoperative AKI stage and renal pathological changes, logistic regression analysis results showed that perirenal after PRB was not independently correlated with preoperative dialysis (β=0.568, P=0.241); Multivariate logistic regression analysis resluts showed that hematoma (≥5 cm) after PRB was also not independently correlated with preoperative dialysis (β=0.967, P=0.958). Conclusions Preoperative hemodialysis does not reduce the risk of bleeding complications after PRB in patients with AKI. The role of preoperative hemodialysis in reducing the risk of bleeding complications after PRB needs further study and verification. Key words: Acute kidney injury; Renal dialysis; Postoperative complications; Percutaneous renal biopsy; Bleeding complications