Impact of embolic agents on outcomes of renal angiomyolipoma embolization: a dual-center retrospective cohort study

Purpose: Transcatheter arterial embolization (TAE) is widely used for managing renal angiomyolipoma (AML) to prevent hemorrhage and control symptoms while preserving renal function. However, the optimal embolic material remains undetermined due to limited comparative data. This study aimed to compare the effectiveness of ethanol-based embolization versus polyvinyl alcohol (PVA) and to evaluate additional benefits of microcoil use in ethanol-based treatments.Materials and Methods: We retrospectively analyzed 119 patients with single renal AML who underwent TAE at two tertiary centers between 2005 and 2023. Patients were grouped into ethanol-based (ethanol alone or ethanol plus microcoil, n = 93) and PVA (n = 26) cohorts. Subgroup analysis compared ethanol alone (n = 24) versus ethanol plus microcoil (n = 69). Inverse probability treatment weighting and linear mixed-effects models were used to assess tumor volume reduction and treatment response (≥50% volume reduction).Results: After adjustment, the ethanol group demonstrated significantly greater tumor volume reduction than the PVA group at 6 and 12 months (adjusted mean difference = –23.9%, p = 0.002; –23.1%, p = 0.001) and a higher response rate (92.1% vs. 78.4%, p = 0.043). In the subgroup analysis, ethanol plus microcoil achieved higher response (91.3% vs. 73.8%; OR, 3.73; p = 0.038) and lower recurrence (7.1% vs. 30.2%; OR, 0.18; p = 0.008) compared with ethanol alone.Conclusion: Ethanol-based embolization provides superior tumor control compared to PVA in renal AML, and the addition of microcoils enhances early volume reduction and reduces recurrence, supporting its use as an effective treatment strategy.