Natural history and pathophysiology of arteriovenous malformations.

AVMs are congenital malformations of central nervous system blood vessels. The majority of lesions become symptomatic prior to age 40. Hemorrhage and epilepsy are the most frequent presenting symptoms. Disabling headache, transient, progressive, and permanent neurological deficit, heart failure, hydrocephalus, macrocephaly, and intellectual impairment may also occur. Long-term mortality is approximately 18%, and morbidity leading to disability occurs in 30% of patients. Aggressive management when possible is indicated.