Cerebrovascular Support for Cognitive Processing in Hypertensive Patients Is Altered by Blood Pressure Treatment

Abstract

Abstract-Hypertension is associated with mild decrements in cognition. In addition, regional cerebral blood flow responses during memory processing are blunted in parietal and thalamic areas among untreated hypertensive adults, who, compared with normotensive subjects, manifest greater correlation in blood flow response across task-related brain regions. Here, we test whether pharmacological treatment of hypertension normalizes regional cerebral blood flow responses and whether it does so differentially according to drug class. Treatment with lisinopril, an angiotensinconverting enzyme blocker, known to enhance vasodilative responsivity, was compared with treatment with atenolol, a ␤-blocker. Untreated hypertensive volunteers (nϭ28) were randomly assigned and treated for 1 year. Whole brain and regional cerebral flow responses to memory processing and acutely administered acetazolamide, a vasodilator, were assessed pretreatment and posttreatment. Peripheral brachial artery dilation during reactive hyperemia was also measured. Quantitative blood flow measures showed no difference in the magnitude of regional cerebral blood flow responses pretreatment and posttreatment to either memory tasks or acetazolamide injection. Brachial artery flow-mediated dilation increased with treatment. No differences between medications were observed. In brain regions active in memory processing, however, regional cerebral blood flow responses were more highly correlated after treatment. Specificity of cerebral blood flow to different regions appears to decline with treatment of hypertension. This greater correlation among active brain regions, which is present as well in untreated hypertensive relative to normotensive volunteers, may represent compensation in the face of less region-specific responsivity in individuals with hypertension. M ild-to-moderate hypertension is associated with minor deficits in cognition. [1][2][3][4] Brain structure or function might account for these deficits. [5][6][7][8] Cognitive processing elicits a regional redistribution of blood flow, providing metabolic support to active neural areas. 9 Interference with this redistribution, blunting of regional blood flow, or structural loss because of poor perfusion might underlie the deficits of hypertensive individuals. Limited existing evidence supports all of these possibilities. [5][6][7][8]10 We demonstrated that, compared with normotensive individuals, those with hypertension have damped regional cerebral blood flow (CBF; rCBF) responses in parietal and thalamic areas (regions of interest [ROI]) during working memory tasks and greater correlation among rCBF responses across task-related regions. 7 Both observations might be because of a cerebrovascular adaptation to hypertension, most particularly, the remodeling of walls of small arteries, ie, thickening of the medial layer with or without a change in lumen diameter. 7 Antihypertensive medications have established influences on peripheral vascular function and may have similar effects on cerebrovascular...

Ausência de relação entre hipertensão arterial sistêmica e desempenho cognitivo em idosos de uma comunidade

“…Estima-se que a hipertensão arterial, quando tratada, não cause prejuízos às funções cognitivas 12 , porém, segundo Birns et al 13 , deve-se tomar cuidado com a redução indiscriminada da pressão arterial, que também pode ser prejudicial ao funcionamento cognitivo.…”

Brain Indices Predict Blood Pressure Control

“…Clearly there is evidence supporting the choice of these drug types in terms of vascular remodeling and cerebral blood flow. 4 As pointed out by Jennings et al, 5 neither passes the blood-brain barrier, thus allowing the results to be interpreted in terms of vascular, rather than neuronal, effects; and in some studies, in comparison to ␤-blockers, ACE-Is reverse the peripheral vascular remodeling that occurs with hypertension. Thus, ACE-Is and ␤-blocking agents, as well as other antihypertensive medications, eg, angiotensin-receptor blockers, remain good candidates for larger trials.…”

“…It may be a key element, because information-processing tasks elicit active changes in the regional distribution of blood flow, thus providing metabolic support to neural areas. 5 Do other information processing tasks, eg, episodic memory or executive functioning, afford a better or poorer prediction of treatment success, and, if so, are results specific to the thalamic region? Working memory-provoked rCBF activity in the parietal region added nothing to the prediction.…”

“…9 The exciting feature of work in Jennings' laboratory is that it considers the "flip side" of the relations between cognition and rCBF. 5 Cerebral blood flow dynamics not only influence cognition, but the reverse is true. 3,5 This opens exciting new areas of research for those of us who study hypertension and cognition.…”

“…5 Cerebral blood flow dynamics not only influence cognition, but the reverse is true. 3,5 This opens exciting new areas of research for those of us who study hypertension and cognition. The Jennings et al 3 paradigm will contribute important information to population-based studies of effective treatment strategies at different ages.…”