Predictors of clinically significant hemorrhage following ultrasound-guided percutaneous renal biopsy in pediatric patients.

BACKGROUND: Ultrasound-guided percutaneous renal biopsy is a cornerstone in the evaluation of pediatric kidney disease, with post-biopsy hemorrhage being the most common complication. Multiple predictors of post-biopsy bleeding have been identified in the adult population; however, data on risk factors in children is limited. OBJECTIVE: The purpose of our study is to determine any risk factors of post-biopsy hemorrhage in children. MATERIALS AND METHODS: This IRB-approved retrospective study included pediatric patients who had native or transplant renal biopsy between 2010-2024. The primary outcomes included decrease of hemoglobin of >15 g/L measured 4-6 h post biopsy and/or presence of a sizable perinephric hematoma (defined as ≥5 mL) measured on immediate post-biopsy ultrasound. The association between presence of hematoma and significant change in Hb was assessed, and the association of 12 different preselected risk factors with these co-primary outcomes was analyzed. RESULTS: Among 207 patients included (median age 11 years [IQR, 7-14]), 170 (82%) underwent native kidney biopsy and 37 (18%) transplant kidney biopsy. A post-biopsy hemoglobin decrease ≥15 g/L occurred in 23 patients (11%; 95% CI, 8-16%), and 27 (13%; 95% CI, 9-18%) developed a sizable perinephric hematoma. A hematoma ≥5 mL on immediate post-procedural imaging was associated with a hemoglobin decrease ≥15 g/L (OR 4.6, 95% CI 1.5-13.4; P=0.004). No other factors were significantly associated with hemoglobin decline or hematoma after correction for multiple testing. CONCLUSION: Immediate post-biopsy ultrasound findings may help predict clinically significant post-biopsy hemorrhage, while no other risk factors were identified.