Arteriovenous Malformations in the Brain

Arteriovenous malformations (AVM) are a leading cause of intracerebral hemorrhage, especially among the young. Because they pose a lifelong risk of serious bleeding, definitive treatment to obliterate the AVM should be pursued in the majority of patients. Microsurgical resection of a small AVM located in the superficial or non- eloquent brain achieves high cure rates with low morbidity, and is the recommended choice for such lesions. Radiosurgery with gamma knife, linear accelerator, or heavy ion beam irradiation is an alternative therapy for AVM treatments less than 3 centimeters in diameter located in brain regions where surgery is likely to produce major neurologic deficits, or for patients unable or unwilling to undergo craniotomy and resection. Cure rates are lower than with microsurgery, and obliteration of the lesion may take 2 to 3 years, during which time the patient remains at risk for hemorrhage. Because rates of recurrent hemorrhage are higher than rates of initial bleeding, radiosurgery may be a good option for patients who have not yet had an intracranial hemorrhage. Endovascular embolization as sole therapy is curative only in a small percentage of cases, but is recommended as part of a multimodal approach to reduce the size of a large AVM, and decrease bleeding risk of lesions with multiple or inaccessible feeding vessels or associated aneurysms prior to surgery or radiotherapy. Currently, treatment decisions must rely solely on Class III evidence from case series and expert opinion. Randomized clinical trials are needed to provide objective guidelines for the future management of patients with an AVM.