In mild hypertensive patients, regional cerebral blood flow, measured by positron emission tomography, was reduced in the frontal cortex and basal ganglia compared with normotensive patients. In moderate to severe hypertensive patients, cerebral oxygen metabolism was diminished, although the patients were neurologically intact. In elderly hypertensives, white matter vascular lesions on brain imaging were more frequent and cognitive function was impaired, compared with age-matched normotensives.In nontreated spontaneously hypertensive rats (SHR), local cerebral blood flow was decreased in the cortex and thalamus, compared with normotensive rats (NTR). Spatial memory and learning in maze tests were more impaired in aged SHR than in old NTR or young SHR. This inpairment was related to decreased cerebral glucose utilization in the medial septal nucleus, hippocampus, and other regions of the brain. Reduced cerebral blood flow, increased media thickness of the cerebral arteries and impaired cognitive function in SHR were improved by long-term antihypertensive treatment. In humans as well as animals, long-standing hypertension per se leads to reductions in cerebral blood flow, metabolism, and cognitive function, each of which possibly may be improved by controlling hypertension with long-term antihypertensive treatment. (Hypertens Res 1995; 18: 111-117) Key Words: cerebral blood flow, brain metabolism, cognitive function, brain morphology, antihypertensive treatmentHypertension is recognized as one of the major risk factors for cerebrovascular diseases, which are more common in Japanese or Orientals than in Caucasians (1, 2, 3). Cerebral hemodynamics, metabolism and function in hypertension before the development of cerebrovascular disease, however, are not fully understood in humans or in animals. In this communication, we contrast cerebral blood flow (CBF) and oxygen metabolism, measured by positron emission tomography in hypertensive patients, with those in normotensive patients. We also report on cognitive function tested by neuropsychological examinations and brain morphology studied by brain imaging in elderly hypertensives and normotensives. In addition, cerebral circulation and metabolism, and memory function were examined in young and old spontaneously hypertensive rats (SHR) and compared with normotensive rats. Finally, we discuss the effects of long-term antihypertensive treatment on the brain circulation, vascular morphology and cognitive function in SHR.Cerebral Blood Flow and Metabolism in Hypertension 1. Mild Hypertension Regional CBF and oxygen metabolism were measured using positron emission tomography (PET) in seven normotensive and eight mild hypertensive patients with mean arterial pressure (MAP) ranging from 81-130 mmHg (4). There were significant negative correlations between MAP and CBF in the cortex and the thalamus, indicating that CBF decreases with a rise in blood pressure (Fig. 1). These findings are inconsistent with previous evidence that hypertension per se did not change the CBF and ...

The extension and volume of hematomas, indicating direct cerebral damage, are useful indicators of mortality from thalamic hemorrhage, motor functional outcome, and level of activities of daily living after 6 months. The disturbance of consciousness and ventricular extension of the hematoma, suggesting diffuse brain damage, could be predictors of cognitive function.

The aim of this study was to examine the levels of cerebral blood flow in relation to motor and cognitive functions in 300 chronic unilateral stroke patients (age, 64 +/- 12 years; mean +/- SD). Cerebral blood flow was measured by the 133Xe inhalation method, adjusted for age, sex, and PCO2 level. Motor function was scored according to Brunnstrom hemiplegic staging and cognitive function according to the Hasegawa dementia rating scale tested in Japanese. Asymmetries of blood flow between affected and nonaffected hemispheres increased with lesion size and were highest in 11 embolic strokes (20 +/- 9%) and higher in 80 nonembolic cortical infarctions (11 +/- 11%) and 76 hemorrhages (9 +/- 7%) than in the group of 133 subcortical infarctions (2 +/- 6%) or 16 control subjects (1 +/- 2%). Severity of hemiparesis correlated with decreased cerebral blood flow in the affected hemisphere (P < .01) and increased hemispheric asymmetries of blood flow (P < 001). Cognitive impairments, after adjusting for age, correlated with decreased cerebral blood flow in the nonaffected hemisphere (P < .0001), left hemispheric lesions (P < .0005), and embolic stroke (P < .005) but not with asymmetries of blood flow. Among 67 patients having bilateral reductions of cerebral blood flow, 25 patients with left hemispheric lesions showed more severe cognitive impairments than among 42 patients with right hemispheric lesions (P < .05). We confirmed that severity of hemiparesis correlated with the degree of asymmetries of cerebral blood flow, reflecting the extent and location of the lesions. Bilateral reductions of cerebral blood flow in patients with left hemispheric lesions may in part contribute to cognitive impairments, indicating reductions of global neuronal activities in the contralateral hemisphere or diffuse cerebrovascular changes. Further studies of cerebral metabolism and follow-up of cerebral circulation are required to reveal the pathophysiology and clinical consequences.

To elucidate the effects of prolonged hypertension on brain function during aging, we examined learning of an eight-arm radial maze task and local cerebral glucose utilization in young-adult (3 to 4 months old) and aged (16 to 17 months old) spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY). Young-adult SHR learned the task more slowly than young-adult WKY, but cerebral glucose utilization, measured by the [14C]2-deoxyglucose method in 24 brain structures, was not significantly different in the two groups. The aged SHR and WKY exhibited impaired learning ability. Cerebral glucose utilization was reduced (13% to 23%) in six regions in aged WKY and in 12 regions in aged SHR compared with values in the respective young-adult groups. Furthermore, the aged SHR showed a greater disturbance of learning acquisition and more profound reduction of cerebral glucose utilization in five regions than the aged WKY. In SHR, hypometabolism, indicated by a decrease in glucose utilization in 15 brain structures including the cerebral cortex, hippocampus, and visual system, was significantly correlated with impaired learning acquisition, indicated by an increase in total error choices. These findings show that (1) hypertension per se does not impair maze learning or cerebral glucose utilization in young-adult rats, and (2) brain function is impaired during aging and prolonged hypertension is an additional factor facilitating brain dysfunction associated with neuronal hypoactivities, resulting in behavioral deterioration including learning disability. Thus, early control of hypertension seems important for preventing or reducing brain dysfunction in senescence.

Background and Purpose: Possible effects of changes in blood pressure on the cerebral circulation were studied in patients with chronic stroke and age-matched nonstroke control subjects at 28±10 months (mean+SD) (range, 18 to 54 months) and 27±6 months (range, 19 to 44 months), respectively, after the first measurement.Methods: Cerebral blood flow was measured by the`3Xe inhalation method in 55 patients (mean+SD age, 62± 11 years; 39 with brain infarction and 16 with hemorrhage) and 10 control subjects (mean±SD age, 61±9 years). Correlations between changes in cerebral blood flow and blood pressure were evaluated.Results: Among brain infarctions, average cerebral blood flow did not change from the first study; however, changes in cerebral blood flow in each individual were closely related to changes in systolic and mean arterial blood pressures (P<.01 and P<.05, respectively). Of these, in 10 patients with cerebral blood flow decreased more than 15% from the initial levels, systolic and mean arterial blood pressures decreased by 25±32 mm Hg and 16±+14 mm Hg (P<.05 and P<.005, respectively). In contrast, in 29