Brain atrophy in hypertension. A volumetric magnetic resonance imaging study.

Abstract

To determine whether hypertension, the predominant risk factor for stroke and vascular dementia, is associated with brain atrophy, magnetic resonance imaging (MRI) scans were performed to quantify brain volumes and cerebrospinal fluid spaces. Eighteen otherwise healthy, cognitively normal older hypertensive men (mean±SD age, 69±8 years, duration of hypertension 10-35 years) and 17 age-matched healthy, normotensive male control subjects were studied in a cross-sectional design. Axial proton-density image slices were analyzed using region-of-interest and segmentation analyses. The hypertensive subjects had significantly larger mean volumes of the right and left lateral ventricles (p<0.05, both absolute volume and volume normalized to intracranial volume) and a significantly smaller normalized mean left hemisphere brain volume (p<0.05) with a trend toward significance for a smaller normalized mean right hemisphere volume (p<0.Q9). Four hypertensive subjects and one healthy control subject were found to have severe peri ventricular hyperintensities on T2-weighted MRI images. When data for these subjects were removed from the analyses, the normalized lateral ventricle volumes remained significantly larger in the hypertensive group. Lateral ventricle enlargement was not related to age or use of diuretics in the hypertensive group nor to duration of hypertension between 10 and 24 years. Our findings suggest that long-standing hypertension results in structural changes in the brain. Longitudinal studies will determine whether MRI-associated changes are progressive and if such changes identify hypertensive subjects at increased risk for clinically apparent brain dysfunction. 1 " 3 Nevertheless, hypertension remains the dominant risk factor for stroke and vascular dementia.4 -6 Hypertension-associated changes in the cardiovascular and renal systems have been well described by clinical studies, using readily available, noninvasive techniques such as echocardiography 7 -8 or creatinine clearance calculated from 24-hour urine measurements. 9 In vivo changes in the brains of hypertensive subjects are less commonly described, most likely because of fewer available methods for noninvasrvery studying the brain. In particular, there has been little emphasis on characterizing brain structure and function in hypertensive subjects in the absence of stroke or dementia.With more widespread availability of structural imaging modalities such as computed x-ray tomography (CT) and magnetic resonance imaging (MRI), methods have been developed to not only describe, but also quantify structural changes in the brain 1011 associated with normal, healthy aging 12 -15 and with various pathological conditions such as Alzheimer's disease 16 and Down's syndrome. 17 However, there has been only one volumetric imaging study, using CT, that applied these techniques to hypertensive subjects. In that retrospective cross-sectional study, Hatazawa et al 18 reported greater brain atrophy in older hypertensive subjects, including those with left ventricular...

Genomic Susceptibility Loci for Brain Atrophy in Hypertensive Sibships From the GENOA Study

“…22 We believe this study provides the first estimate of the heritability of brain atrophy, which is another recognized risk factor for cognitive impairment in the elderly. 5,23,24 The bivariate linkage analyses of brain atrophy and PP provided the strongest evidence of genes with pleiotropic effects on measures of BP and brain injury. Of the regions on chromosomes 11 and 16 that satisfied the bivariate criteria for significant evidence of linkage, the chromosome 11p15 region was detected in the univariate linkage analyses of PP but not brain atrophy, whereas the chromosome 16q region was detected in the univariate linkage analyses of brain atrophy but not PP.…”

“…Both brain traits have been associated with hypertension and with cognitive dysfunction. 5,6 Moreover, measures of brain anatomy and ischemic brain injury appear to be heritable. 2,7 In addition to performing genome-wide univariate linkage analyses, we leveraged the power of multivariate linkage analyses by also conducting bivariate linkage analyses of each brain measure with a measure of steady-state BP level, ie, mean arterial pressure (MAP), and a measure of the pulsatile component of BP, ie, pulse pressure (PP).…”

Voxel-based morphometry demonstrates reduced grey matter density on brain MRI in patients with diabetic retinopathy

“…Hypertension has been associated with changes in brain structure and cognitive function [40][41][42][43]. It is known that hypertension accelerates the decline in cerebral perfusion [44,45].…”

Acceleration of cerebral ventricular expansion in the Cardiovascular Health Study

“…Previous studies have suggested that faster rates of ventricular expansion may be associated with AD pathology, APOE ε-4 carrier status, and cardiovascular risk factors such as hypertension and diabetes [3,8,31,35,12,29,2,25,15]. However, since most previous studies measure ventricular volume at one or two time points per subject, they are limited in the information they can provide about the time course of ventricular expansion.…”