Arteriovenous malformations of the brain: natural history in unoperated patients.

Two-hundred and seventeen patients from a total population of 343 patients with arteriovenous malformations, were managed without surgery. Follow up was for a mean of 10.4 years. Using life survival analyses, there was a 42% risk of haemorrhage, 29% risk of death, 18% risk of epilepsy and a 27% risk of having a neurological handicap by 20 years after diagnosis in unoperated patients.