Hypertension and longitudinal changes in cerebral blood flow: the SMART-MR study.
ABSTRACT Cerebral hypoperfusion is among the mechanisms that may explain the association of high blood pressure (BP) with dementia. However, few data are available on the longitudinal association of hypertension and cerebral perfusion.
We examined the longitudinal association of hypertension, BP, and antihypertensive drugs with change in parenchymal cerebral blood flow (pCBF) in 575 patients with manifest atherosclerotic disease (mean age, 57 ± 10 years) from the SMART-MR study. Total CBF was measured at baseline and at follow-up with magnetic resonance (MR) angiography and was expressed per 100ml brain volume as an indicator of cerebral perfusion. Automated brain segmentation was used to quantify brain tissue volumes and cerebrospinal fluid on MR imaging.
Mean (standard deviation [SD]) baseline pCBF was 52.3 (9.8) ml/min/100ml and after 3.9 years (range, 3.0-5.8 years) of follow-up declined to 50.7 (10.3) ml/min/100ml. Regression analyses adjusted for age, sex, follow-up time, and vascular risk showed that untreated and poorly controlled hypertension and higher levels of systolic and diastolic BP (per SD) were significantly associated with a decline in pCBF; mean differences in decline (95% confidence interval) were -2.2 (-4.4 to 0.0), -1.0 (-1.8 to -0.1), and -1.0 (-1.8 to -0.2) ml/min/100ml. In addition, within hypertensive patients (n = 469), patients using angiotensin receptor blockers (ARBs) did not show a decline in pCBF, whereas patients using other antihypertensive drugs did show a decline in pCBF.
Untreated hypertension, poorly controlled hypertension, and high BP levels are associated with a decline in pCBF. In addition, treatment with ARBs might result in less decline in pCBF than other antihypertensive treatment.
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ABSTRACT: Vascular risk factors and cerebral blood flow (CBF) reduction have been linked to increased risk of cognitive impairment and Alzheimer's disease (AD); however the possible moderating effects of age and vascular risk burden on CBF in late life remain understudied. We examined the relationships among elevated vascular risk burden, age, CBF, and cognition. Seventy-one non-demented older adults completed an arterial spin labeling MR scan, neuropsychological assessment, and medical history interview. Relationships among vascular risk burden, age, and CBF were examined in a priori regions of interest (ROIs) previously implicated in aging and AD. Interaction effects indicated that, among older adults with elevated vascular risk burden (i.e., multiple vascular risk factors), advancing age was significantly associated with reduced cortical CBF whereas there was no such relationship for those with low vascular risk burden (i.e., no or one vascular risk factor). This pattern was observed in cortical ROIs including medial temporal (hippocampus, parahippocampal gyrus, uncus), inferior parietal (supramarginal gyrus, inferior parietal lobule, angular gyrus), and frontal (anterior cingulate, middle frontal gyrus, medial frontal gyrus) cortices. Furthermore, among those with elevated vascular risk, reduced CBF was associated with poorer cognitive performance. Such findings suggest that older adults with elevated vascular risk burden may be particularly vulnerable to cognitive change as a function of CBF reductions. Findings support the use of CBF as a potential biomarker in preclinical AD and suggest that vascular risk burden and regionally-specific CBF changes may contribute to differential age-related cognitive declines.Frontiers in Aging Neuroscience 01/2014; 6:159. · 5.20 Impact Factor
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ABSTRACT: Objective Elevated levels of N-terminal pro-brain natriuretic peptide (NT-proBNP) are associated with cognitive impairment, which might be explained by cardiovascular diseases or risk factors. The aim of this study was to investigate the association of NT-proBNP with cognitive function and decline in older adults at high risk of cardiovascular disease. Methods We studied 5205 men and women (mean age 75 years) who were recruited into the PROspective Study of Pravastatin in the Elderly at Risk. All participants had pre-existing cardiovascular disease or risk factors thereof. Four domains of cognitive function were tested at baseline and repeated during a follow-up period of 3.2 years. Results Participants with higher NT-proBNP (≥ 450 ng/L) had a worse baseline cognitive function including reaction time (mean difference high vs. low group (95% CI)) 3.07 seconds (0.83; 5.32); processing speed -1.02 digits coded (-1.65; -0.39) and immediate memory -0.13 pictures remembered (-0.29; 0.04). There was no significant difference in delayed memory (-0.14 (-0.38; 0.10)) between the NT-proBNP groups. Participants with higher NT-proBNP had a steeper cognitive decline, including reaction time (mean annual change high vs. low group (95% CI)) 0.60 seconds (0.14; 1.07); processing speed -0.15 digits coded (-0.25; -0.05); immediate memory -0.05 pictures remembered (-0.09; 0.00); delayed memory -0.05 pictures remembered (-0.11; 0.01). Associations were independent of cardiovascular diseases and risks. Interpretation Higher NT-proBNP associates with worse cognitive function and steeper cognitive decline, independent of cardiovascular diseases and risks. Further studies to unravel the underlying mechanisms are warranted. ANN NEUROL 2014. © 2014 American Neurological Association.Annals of Neurology 06/2014; · 11.19 Impact Factor
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ABSTRACT: Apelin is a recently described endogenous peptide and its receptor APJ, is a member of the G protein-coupled receptors family. Apelin and APJ are widely distributed in central and peripheral tissues exert important biological effects on cardiovascular system. Recent studies have suggested that apelin/APJ system involves in decreasing the blood pressure and have a close relationship with hypertension, presumably, pathophysiology of hypertension as well. Such as, apelin/APJ system may be concerned in hyperfunction of the sympathetic nervous system, renin-angiotensin-aldosterone system, endothelial injury, excessive endothelin, sodium retention, vascular remodeling, insulin resistance elicit hypertension, as well as in hypertension-induced organ damaged. Meanwhile, on the ground of the variation of apelin level in hypertension therapeutic process and combining with the recently researches on APJ agonist and antagonist, we could infer that apelin/APJ system would be a promising therapeutic target for hypertension and other cardiovascular disease in the future. However, the role of apelin on these pathogenic conditions was not consistent, consequently, the contradictory role of apelin on these pathogenesis of hypertension would be discussed in this article.Molecular Biology Reports 07/2014; · 2.51 Impact Factor