Abstract
Cerebral hemodynamics were studied in 3 patients with supratentorial arteriovenous malformations (AVMs). Cerebral blood flow (CBF) was measured by the methods using 123I-IMP SPECT (IMP SPECT) and stable xenon CT (Xe-CT) before and after surgery. In addition, the cortical blood flow (CoBF) adjacent to AVMs was monitored during surgery using laser Doppler flowmetry. Preoperative CBF measurements were performed more than a month after stroke.
Case 1: A 48-year-old man developed disturbance of consciousness, right hemiparesis and motor dysphasia. Cerebral angiography disclosed a 3.5cm left frontal AVM fed by middle cerebral artery. In preoperative IMP SPECT and Xe-CT, hypoperfusion and low CBF were observed in the left frontoparietal region adjacent to the AVM. The CoBFs of the left frontal lobe were increased moderately during clipping of feeders and after excision of the AVM.
Case 2: A 51-year-old woman had vomiting and right hemiparesis. Angiography demonstrated a 2.0cm left parietal AVM. In preoperative CBF studies, neither hypoperfusion nor low CBF was seen in the areas surrounding the AVM. There were no alterations of CoBFs before and after excision.
Case 3: A 62-year-old man had a 5.0cm left frontoparietal AVM supplied by anterior and middle cerebral arteries. Preoperative CBF studies showed marked hypoperfusion and ischemia in the regions adjacent to as well as distant from the AVM. A large increase in CoBF up to two or three times the preexcision value was noted after total excision of the AVM. He developed the normal perfusion pressure breakthrough (NPPB) syndrome after operation. High dose barbiturate anesthesia combined with induced hypotension was maintained for 5 days and resulted in good outcome.
From reported clinical observations and hemodynamic data in this study, it is suggested that factors contributing to the development of NPPB syndrome include:(1) a large, high-flow AVM;(2) marked hypoperfusion and ischemia in the regions adjacent to as well as distant from an AVM;(3) low CoBF around an AVM; and (4) substantial increase in CoBF after AVM removal. Preoperative and intraoperative CBF measurements may be useful for perioperative management of a large, highflow AVM.
