Predictors of Hemorrhage and Re-Intervention in Renal Angiomyolipoma Following Transcatheter Arterial Embolization

Purpose: Renal angiomyolipomas (AMLs) are benign renal neoplasms that may lead to spontaneous hemorrhage. Transcatheter arterial embolization (TAE) is a nephron-sparing treatment option, yet data on predictors of hemorrhage and re-intervention remain limited. This study evaluates clinical and radiologic outcomes of TAE and identifies predictors of hemorrhage and repeat embolization. Materials and Methods: A retrospective review of 66 patients (69 AMLs) undergoing TAE between 2010 and 2024 was conducted. Clinical, radiological, and procedural variables were analyzed. Tumor size, vascularity, and aneurysmal features were assessed pre- and post-embolization. Logistic regression models identified predictors of hemorrhage and repeat TAE. Results: Pre-treatment tumor diameter was the only significant predictor of hemorrhage (p = 0.011), with a threshold of 6.8 cm yielding 84.6% sensitivity and 71.3% specificity. All hemorrhagic tumors measured ≥4 cm. Post-embolization tumor volume predicted repeat TAE (p = 0.001), with a 248 mL cutoff. TAE significantly reduced tumor diameter (-33.5%) and volume (-60%) (p < 0.001). Radiologic success was achieved in 97% of cases, with a durable success rate of 84%. Clinical success was 94%, and complications occurred in 7.2% of patients, including two major events. Conclusions: TAE is a safe and effective treatment for renal AMLs. Tumor diameter >6.8 cm is a strong predictor of hemorrhage, while larger post-embolization volumes predict the need for re-intervention. These findings challenge the conventional 4 cm treatment threshold and support more individualized management strategies incorporating tumor morphology and response to embolization.