[Cerebral vasospasm following subarachnoid hemorrhage in arteriovenous malformation].

Cerebral vasospasm after SAH from AVMs is rare. Only few reports have been made. Vasospasm was confirmed in 4 out of 13 patients with SAH from AVMs at the Sagamihara National Hospital in the past 5 years. The incidence of vasospasm following rupture of AVM is higher than those in previous reports ranging between 8 and 12 percent. This high incidence (31%) might be attributable to the timing from the last SAH attack until angiography. The existence of massive subarachnoid blood clots around the arteries of the circle of Willis is the most important factor causing vasospasm after SAH from AVMs.