1991 年 4 巻 1 号 p. 21-27
Indication and limits of TCD for diagnosis and treatment were evaluated in 20 normal subjects and 15 patients with arteriovenous malformations 5 (AVM), Blood flow velocity of AVM supplying arteries (feeders), namely the middle cerebral artery and others were measured, and pulsatility index (PI) and resistance index (R) were calculated. To see pCO2 reactivity, hyperventilation was perfarmed (deep breath, twice/5s for 30s) .
In patients, flow velocity increased remarkably and both of PI and R decreased significantly. Reactivity against hypocapnia also showed significant decrease. These changes varied according to the relationship between the artery and the nidus, and cases were divided into three groups, namely: main (Group A), partial (Group B) and poor (Group C) angioma supplying arteries. Significant changes were seen in Group A.
Postoperatively, these changes recovered to the normal range. After removal of the AVM, flow velocity and vascular reactivity were closely related with the condition of the brain tissue which surrounded the nidus before the removal. NPPB tends to occur in such areas especially in Group A.
As a conclusion, characteristic changes were recognized in hemodynamics and pCO2 reactivity of feeders, especially on mainly angioma supplying arteries. In such cases, care should be taken to guard against the normal perfusion pressure breakthrough phenomenon during and after surgery.