Effect of nicardipine on cerebral blood flow in hypertensive patients with internal carotid artery occlusion: a PET study.
OBJECTIVE
The objective of this study was to elucidate the effect of intravenous administration of nicardipine on the cerebral blood flow of hypertensive patients with internal carotid artery occlusion (ICAO).


METHODS
Six patients with ICAO and 10 normal individuals were examined by positron emission tomography. The cerebral blood flow (CBF), cerebral blood volume (CBV), cerebral metabolic rate of oxygen, oxygen extraction fraction (OEF) and CBF/CBV ratio were evaluated for each vascular territory and each hemisphere, and the interhemispheric asymmetry index of each parameter was also calculated. Nicardipine was administered intravenously to each patient, and the changes in CBF (DeltaCBF%) and in blood pressure (DeltaBP) were examined.


RESULTS
After the administration of nicardipine, the CBF was significantly increased in the patient hemisphere and was unchanged in the occluded hemisphere. Stepwise regression analysis disclosed that the DeltaBP and asymmetry index of OEF were significantly correlated with the DeltaCBF% in the occluded hemisphere.


CONCLUSIONS
These results suggest that CBF is unchanged or increased in ICAO patients after nicardipine administration, but that excessive reduction of blood pressure may lead to CBF decrease in the patients with marked hemodynamic imbalance between the occluded and patent hemispheres. These results suggest that it is advisable not to reduce blood pressure excessively in these patients in the treatment of perioperative or acute hypertension with calcium antagonist.
Nagahama
Y
Y
Department of Neurology, Kyoto University, Kyoto, Japan.
Fukuyama
H
H
Yamauchi
H
H
Katsumi
Y
Y
Dong
Y
Y
Konishi
J
J
Kimura
J
J