[The characteristics of the cerebral circulation in arterial hypertension].

In arterial hypertension, cerebral blood flow (CBF) in patients with chronic cerebrovascular diseases is lower than in patients without hypertension. In stenosis of internal carotid arteries, hypertension leads to the disturbance of the response of resisting cerebral vessels compensating the decrease of perfusion pressure at the expense of vessel dilation. As compared with patients without hypertension, the difference between the values of regional CBF (rCBF) in various regions of the brain is more obvious with the appearance of alternate hypoemic and hyperemic regions. After nifedipine, both an increase and a decrease of hemispheric CBF is possible in these patients. In many of them such changes in CBF are combined with further increase of the difference between rCBF values in various parts of the brain with the formation of well marked zones with relative ischemia and hyperemia.