CEREBRAL CIRCULATION AND METABOLISM IN HYPERTENSION

Abstract

Measurements of cerebral hemodynamics and cerebral oxygen consumption (CMRO2) were made by the nitrous oxide method in 60 patients with essential hypertension.The mean values for cerebral blood flow (CBF) and CMRO2 were significantly lower (P<0.05) than normal values noted for healthy young men. The mean cerebral vascular resistance (CVR) was significantly higher than normal value (P<0.01). In these hypertensive patients the influence of aging on cerebral hemodynamics was studied, and statistically significant correlations was calculated between age and such values as CBF CVR and CMRO2. These findings revealed a decreasing CBF and CMRO2 and an increasing CVR accompanied with advancing age.Comparing these values in hypertensive patients with those in normotensive subjects of the same age, the statistically significant difference was only the significantly increased CVR (P<0.01). The effects of aging on the cerebral hemodynamics in the hypertensive group were more remarkable than that in the normotensive group. These facts were atributed to the more progressive increase of cerebral arteriosclerosis with advancing age in hypertension. The cerebral hemodynamic changes in seven renal hypertensive patients and one patient with coarctation of the aorta were the same with that of essential hypertensive prtients. In five hypertensive arteriosclerotic patients with psychosis CBF and CMRO2 were significantly decreased.There was no relationship between mean arterial blood pressure and CBF and the former and CMRO2. The relation between cerebral hemodynamics and the Keith-Wagener's grade were significant. The proportional increasing cerebral vascular resistance was observed accompanying with advancing in the grade.The cerebral vascular reactivity due to the inhalation of 5 per cent carbon dioxide in essential hypertensive patients was significant.These findings demonstrated that the CVR in hypertension was increased, mostly due to increased cerebral arteriolar tone, but partly due to arteriosclerosis.Finally, clinical implications of these studies were briefly discussed.