Vascular characteristics of intracerebral arteriovenous malformations in patients with clinical steal.

In patients with intracerebral arteriovenous malformations (AVMs), symptoms attributed to steal can lead to progressive debilitating deficits. This study was undertaken to determine which morphologic features of the AVM could be correlated with clinical symptoms of steal. Over a 4-year period, 65 patients with intracranial AVMs were evaluated with angiography supplemented by MR (46 cases) and CT (19 cases). Eleven characteristics of AVM vascular architecture were studied; these included size, lobar location, periventricular/intraventricular location, arterial stenosis, arteriovenous fistulae, angiomatous change (the presence of dilated transcortical collateral circulation), venous drainage pattern (central, cortical, mixed), venous stenosis, venous aneurysm or ectasia, venous variation, and delayed drainage. These characteristics were correlated with a history of clinical steal, which was seen in nine (14%) of 65 patients. Three characteristics were found to correlate highly with steal: angiomatous change (p less than .0001), size (p less than .0001), and peripheral venous drainage (p = .045). The mean size of the AVM nidus was 31.3 cm3 for the entire group of patients, 105.0 cm3 for patients with steal, and 19.5 cm3 for those without steal symptoms. Angiomatous change was seen in six (9%) of 65 patients; all six of these had clinical steal. The association of clinical steal with AVM size, angiomatous change, and peripheral venous drainage may contribute to establishing a prognosis and treatment planning. When a patient's symptoms are caused by steal, treatment with subtotal excision or partial embolization may be beneficial.