Effect of presenting hemorrhage on outcome after microsurgical resection of brain arteriovenous malformations.

Objective: We hypothesized that patients with unruptured arteriovenous malformations (AVMs) at presentation have an increased risk of deterioration compared with patients with ruptured AVMs.

Methods: A consecutive series of 224 patients treated microsurgically by a single neurosurgeon during a period of 6.4 years was analyzed.