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Background Infantile brain arteriovenous malformations (AVMs) are rare congenital lesions associated with substantial neurologic morbidity and mortality. Endovascular management for infantile AVMs has historically been concentrated in select high-volume centers. For both neonates and infants, contemporary multicenter data describing their epidemiology, treatment patterns, and outcomes following endovascular intervention remain limited.Objective To characterize the epidemiology of infantile AVMs in the United States, quantify the distribution of admissions and embolizations across hospitals, and evaluate outcomes among neonates and infants undergoing embolization with a focus on comparing high-volume and low-volume centers.Methods A retrospective analysis of available years of the HCUP KID database between 2006-2022 identified all infantile AVM admissions (age <1 year). Survey-weighted estimates were used to describe national incidence and patient characteristics. Neonates were subsetted as admissions with age <1 month. Hospital-level AVM volume and embolization activity were assessed annually and high-volume was defined on a year-specific basis as the larger of those within the top decile of AVM infant admission volume or ≥2 unweighted admissions within a year. Care centralization was evaluated using Lorenz curves, Gini coefficients, and top-k share metrics. The subset of patients who received embolization were further analyzed and outcomes were assessed between high-volume and low-volume centers using survey-weighted multivariable regression adjusting for demographics, payer, ZIP income quartile, and year.Results Approximately 1,340 patients with infantile AVMs were identified over the study period: the cohort was 56.9% female. Embolization was performed in 20.3% of admissions. The top 10 hospitals by admission volume accounted for up to 44% of embolizations in later years, and high-volume centers accounted for 91.2% of all neonatal embolizations. However, Gini coefficients for embolization distribution declined over time, suggesting an increase in the number of low-volume centers performing embolization for neonatal and infantile patients. Among 273 infants who received embolization, 86.9% of procedures occurred at higher-volume hospitals. After adjustment, embolization at higher-volume centers was associated with significantly lower rates of ischemic stroke (aRR 0.13; 95% CI 0.03-0.52; p=0.004), in-hospital mortality (aRR 0.28; 95% CI 0.16-0.50; p<0.001), and seizures (aRR 0.46; 95% CI 0.22-0.95; p=0.036). Length of stay did not differ significantly by hospital volume (geometric mean ratio 0.69; 95% CI 0.37-1.29; p=0.25). Hemorrhagic complications were uncommon and not significantly different after adjustment.Conclusions Infantile AVMs are rare and remain primarily treated by a small number of high-volume centers. However, the number of low-volume centers attempting to perform neonatal and infantile embolization has increased over the last two decades. Among treated patients, higher procedural volume is associated with significantly improved neurologic and survival outcomes for this vulnerable population. Neonates and infants diagnosed with brain AVMs should be transferred to high-volume centers for management to optimize patient and procedural outcomes.Disclosures A. Devarajan: None. T. Shigematsu: None. D. Goldman: None. T. Hardigan: None. E. Chapman: None. E. Pareek: None. D. Adu-Kyei: None. P. Morgenstern: None. S. Majidi: None. A. Berenstein: None. J. Fifi: None.