Pediatric Arteriovenous Malformations

True parenchymal or pial arteriovenous malformations (AVMs) result in direct shunting between the arterial and venous systems without an intervening capillary bed. Distinct from other vascular malformations—including vein of Galen malformations, cavernous angiomas, and dural arteriovenous fistulas—AVMs are thought to develop as a result of failure of embryogenesis in most cases, and they are the most common cause of hemorrhagic stroke in children after the perinatal period. AVMs in children differ from AVMs in adults with regard to manifestation, natural history, structure, rate of recurrence, and outcomes after surgery. These differences, along with the long potential life span of pediatric patients, alter the considerations given to treatment. Even if a lifetime risk near the low range of the reported spectrum is assumed, the lifetime risk for hemorrhage is substantial for affected children. An increasing awareness of the adverse effects of irradiation on children has led to efforts to reduce ionizing radiation exposure during angiographic procedures. Current consensus opinion advocates treatment for most pediatric AVMs, except when it would cause unacceptable morbidity. Contemporary AVM treatment generally entails resection with microsurgery, radiosurgery, endovascular treatment, or a multimodal combination. In marked distinction to their adult counterparts, AVMs have been noted to recur in several large pediatric case series, even after angiographically verified cure.