Cerebral hyperperfusion during surgical resection of high-flow arteriovenous malformations

Cerebral hemodynamics were evaluated in 16 patients with arteriovenous malformations (AVMs) using intraoperative thermogradient or laser Doppler flowmeter. The postexcision/preexcision blood flow ratio was determined. Two of seven patients with large AVMs (> or = 4 cm) developed a postoperative hematoma. Their flow ratios were larger than 1.9. In 4 patients with large AVMs, their blood flow ratios were reduced from an initial ratio exceeding 2.0 to less than 1.5 using carotid or special flow regulation clamps. These patients did not develop any hemorrhagic complication. In 9 patients of small AVMs (< 4 cm), the ratio was significantly low and there were no hemorrhagic complications.