Increased Hemorrhage Risk With Brain AVM-Associated Aneurysms in Children

INTRODUCTION: Brain arteriovenous malformations (AVMs) represent a major cause of intracranial hemorrhage with pediatric patients at greater lifetime risk of rupture compared to their adult counterparts. These AVMs can be associated with aneurysms that are either arterial or intranidal. The significance of AVM-associated aneurysms in the pediatric population remains poorly understood due to their rare nature and spare reporting. METHODS: We reviewed a prospectively maintained database of pediatric brain AVMs from 1998 to 2021 at the University of California, San Francisco. Inclusion criteria included patients with age ≤ 18 at time of presentation with angiographically-proven AVM. RESULTS: Of 231 patients with AVMs, 24 patients harbored 35 arterial aneurysms, and 35 patients harbored 38 intranidal aneurysms. Compared to AVMs without aneurysms with a mean nidus size of 3.02 ± 1.74 cm, AVMs with intranidal aneurysms had a significantly smaller mean nidus size at 2.13 ± 1.12 cm (p = 0.004). AVMs with intranidal aneurysms had a higher proportion of being ruptured on presentation compared to AVMs without aneurysms (94% vs. 59%, p < 0.001). AVMs with intranidal and arterial aneurysms also underwent higher proportions of surgical resection (92% and 80% vs. 59%, p = 0.001) and embolization (37% and 50% vs. 25%, p = 0.022) with higher rates of nidus obliteration (91% and 79% vs. 65%, p = 0.005). In those that were not obliterated, AVMs with intranidal and arterial aneurysms have higher annual hemorrhage risks (10.2% and 7.4% vs. 1.6%) after patient presentation. Patients who underwent a hemorrhage event after presentation had a higher proportion of worsened clinical status compared to presentation (38% vs. 5.6%, p < 0.001). CONCLUSIONS: A higher proportion of AVMs with associated aneurysms present with hemorrhage and are more likely to undergo additional hemorrhage events when incompletely treated compared to AVMs without aneurysms.