Intensive blood pressure lowering increases cerebral blood flow in older subjects with hypertension

Associations of life-course cardiovascular risk factors with late-life cerebral hemodynamics

While the associations of mid-life cardiovascular risk factors with late-life white matter lesions (WMH) and cognitive decline have been established, the role of cerebral haemodynamics is unclear. We investigated the relation of late-life (69-71 years) arterial spin labelling (ASL) MRI-derived cerebral blood flow (CBF) with life-course cardiovascular risk factors (36-71 years) and late-life white matter hyperintensity (WMH) load in 282 cognitively healthy participants (52.8% female). Late-life (69-71 years) high systolic (B = -0.15) and diastolic (B = -0.25) blood pressure, and mean arterial pressure (B = -0.25) were associated with low grey matter (GM) CBF (p < 0.03), and white matter CBF (B = -0.25; B = -0.15; B = -0.13, p < 0.03, respectively). The association between systolic blood pressure and GM CBF differed between sexes (male/female B = -0.15/0.02, p = 0.04). No associations were found with early- or mid-life cardiovascular risk factors. Furthermore, WMHs were associated with cerebral haemodynamics but not cardiovascular risk factors. These findings suggest that cerebral blood flow autoregulation is able to maintain stable global cerebral haemodynamics until later in life. Future studies are encouraged to investigate why cardiovascular risk factors have differential effects on haemodynamics and WMH, and their implications for cognitive decline.

Effect of antihypertensive deprescribing on hospitalisation and mortality: long-term follow-up of the OPTiMISE randomised controlled trial

BACKGROUND

Deprescribing of antihypertensive medications is recommended for some older patients with low blood pressure and frailty. The OPTiMISE trial showed that this deprescribing can be achieved with no differences in blood pressure control at 3 months compared with usual care. We aimed to examine effects of deprescribing on longer-term hospitalisation and mortality.

METHODS

This randomised controlled trial enrolled participants from 69 general practices across central and southern England. Participants aged 80 years or older, with systolic blood pressure less than 150 mm Hg and who were receiving two or more antihypertensive medications, were randomly assigned (1:1) to antihypertensive medication reduction (removal of one antihypertensive) or usual care. General practitioners and participants were aware of the treatment allocation following randomisation but individuals responsible for analysing the data were masked to the treatment allocation throughout the study. Participants were followed up via their primary and secondary care electronic health records at least 3 years after randomisation. The primary outcome was time to all-cause hospitalisation or mortality. Intention-to-treat analyses were done using Cox regression modelling. A per-protocol analysis of the primary outcome was also done, excluding participants from the intervention group who did not reduce treatment or who had medication reinstated during the initial trial 12-week follow-up period. This study is registered with the European Union Drug Regulating Authorities Clinical Trials Database (EudraCT2016-004236-38) and the ISRCTN Registry (ISRCTN97503221).

FINDINGS

Between March 20, 2017, and Sept 30, 2018, a total of 569 participants were randomly assigned. Of these, 564 (99%; intervention=280; control=284) were followed up for a median of 4·0 years (IQR 3·7-4·3). Participants had a mean age of 84·8 years (SD 3·4) at baseline and 273 (48%) were women. Medication reduction was sustained in 109 participants at follow-up (51% of the 213 participants alive in the intervention group). Participants in the intervention group had a larger reduction in antihypertensives than the control group (adjusted mean difference -0·35 drugs [95% CI -0·52 to -0·18]). Overall, 202 (72%) participants in the intervention group and 218 (77%) participants in the control group experienced hospitalisation or mortality during follow-up (adjusted hazard ratio [aHR] 0·93 [95% CI 0·76 to 1·12]). There was some evidence that the proportion of participants experiencing the primary outcome in the per-protocol population was lower in the intervention group (aHR 0·80 [0·64 to 1·00]).

INTERPRETATION

Half of participants sustained medication reduction with no evidence of an increase in all-cause hospitalisation or mortality. These findings suggest that an antihypertensive deprescribing intervention might be safe for people aged 80 years or older with controlled blood pressure taking two or more antihypertensives.

FUNDING

British Heart Foundation and National Institute for Health and Care Research.

Association of low blood pressure and falls: An analysis of data from the Leiden 85-plus Study

BACKGROUND

Falls and consequent injuries are prevalent in older adults. In this group, half of injury-related hospitalizations are associated with falls and the rate of falls increases with age. The evidence on the role of blood pressure and the use of antihypertensive treatment on the risk of falls remains unclear in oldest-old adults (≥85 years).

OBJECTIVES

To examine the association between systolic blood pressure (SBP) and incident falls with medical consequences in oldest-old adults and to analyse whether this association is modified by the use of antihypertensive treatments or the presence of cardiovascular disease.

METHODS

We analysed data from the Leiden 85-plus Study, a prospective, population-based cohort study with adults aged ≥85 years and a 5-year follow-up. Falls with medical consequences were reported by the treating physician of participants. We assessed the association between time-updated systolic blood pressure and the risk of falling over a follow-up period of five years using generalized linear mixed effects models with a binomial distribution and a logit link function. Subgroup analyses were performed to examine the role of antihypertensive treatment and the difference between participant with and without cardiovascular disease.

RESULTS

We analysed data from 544 oldest-old adults, 242 (44.4%) of which used antihypertensives. In 81 individuals (15%) ≥1 fall(s) were reported during the follow-up period. The odds for a fall decreased by a factor of 0.86 (95% CI 0.80 to 0.93) for each increase in blood pressure by 10 mmHg. This effect was specific to blood pressure values above 130mmHg. We did not find any evidence that the effect would be modified by antihypertensive treatment, but that there was a tendency that it would be weaker in participants with cardiovascular disease (OR 0.81, 95% CI 0.72 to 0.90 per 10mmHg) compared to those without cardiovascular disease (OR 0.94, 95% CI 0.84 to 1.05 per 10mmHg).

CONCLUSION

Our results point towards a possible benefit of higher blood pressure in the oldest-old with respect to falls independent of the use of antihypertensive treatments.

Mean Arterial Pressure and Cerebral Hemodynamics Across The Lifespan: A Cross-Sectional Study From Human Connectome Project-Aging

BACKGROUND

Cerebral perfusion is directly affected by systemic blood pressure, which has been shown to be negatively correlated with cerebral blood flow (CBF). The impact of aging on these effects is not fully understood.

PURPOSE

To determine whether the relationship between mean arterial pressure (MAP) and cerebral hemodynamics persists throughout the lifespan.

STUDY TYPE

Retrospective, cross-sectional study.

POPULATION

Six hundred and sixty-nine participants from the Human Connectome Project-Aging ranging between 36 and 100+ years and without a major neurological disorder.

FIELD STRENGTH/SEQUENCE

Imaging data was acquired at 3.0 Tesla using a 32-channel head coil. CBF and arterial transit time (ATT) were measured by multi-delay pseudo-continuous arterial spin labeling.

ASSESSMENT

The relationships between cerebral hemodynamic parameters and MAP were evaluated globally in gray and white matter and regionally using surface-based analysis in the whole group, separately within different age groups (young: <60 years; younger-old: 60-79 years; oldest-old: ≥80 years).

STATISTICAL TESTS

Chi-squared, Kruskal-Wallis, ANOVA, Spearman rank correlation and linear regression models. The general linear model setup in FreeSurfer was used for surface-based analyses. P < 0.05 was considered significant.

RESULTS

Globally, there was a significant negative correlation between MAP and CBF in both gray (ρ = -0.275) and white matter (ρ = -0.117). This association was most prominent in the younger-old [gray matter CBF (β = -0.271); white matter CBF (β = -0.241)]. In surface-based analyses, CBF exhibited a widespread significant negative association with MAP throughout the brain, whereas a limited number of regions showed significant prolongation in ATT with higher MAP. The associations between regional CBF and MAP in the younger-old showed a different topographic pattern in comparison to young subjects.

DATA CONCLUSION

These observations further emphasize the importance of cardiovascular health in mid-to-late adulthood for healthy brain aging. The differences in the topographic pattern with aging indicate a spatially heterogeneous relationship between high blood pressure and CBF.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY STAGE: 3.

Hypotension and cognitive impairment among the elderly: Evidence from the CLHLS

BACKGROUND

While high blood pressure has been linked to cognitive impairment, the relationship between low blood pressure, especially hypotension, and cognitive impairment has not been well studied. Therefore, this study aimed to assess the prevalence of hypotension and cognitive impairment in the seniors of China, and the association between hypotension and cognitive function impairment.

METHODS

The data was derived from the 2018 wave of the Chinese Longitudinal Healthy Longevity Survey (CLHLS). Systolic blood pressures (SBP) and diastolic blood pressures (DBP) were measured by objective examination. The Chinese version of the Mini-Mental State Examination (CMMSE) was used to evaluate the cognitive impairment of the elderly. Generalized linear models were conducted to evaluate the association of hypotension with cognitive impairment.

RESULTS

The prevalence of hypotension and cognitive impairment in the Chinese elderly were 0.76% and 22.06%, respectively. Participants with hypotension, lower SBP, and lower DBP, had odds ratios of 1.62, 1.38, and 1.48 for cognitive impairment, respectively. Besides, the CMMSE scores decreased by 2.08, 0.86, and 1.08 in the elderly with hypotension, lower SBP, and DBP, compared with those with non-hypotension, higher SBP, and DBP, respectively. Subgroup analyses showed that the association of cognitive impairment with hypotension was stronger in Chinese elderly who had decreased activity of daily living. Moreover, there was statistical evidence of a nonlinear dose-response relationship of SBP and DBP with cognitive impairment (Pnonlinear < 0.05).

CONCLUSION

Hypotension was a potential risk factor for cognitive impairment of the Chinese elderly, especially for those having decreased activity of daily living. Blood pressure management should be conducted to prevent them from cognitive impairment.

Clinical trials in vascular cognitive impairment following SPRINT-MIND: An international perspective

A large interventional trial, the Systolic Blood Pressure Intervention Trial sub-study termed Memory and Cognition in Decreased Hypertension (SPRINT-MIND), found reduced risk of cognitive impairment in older adults with intensive, relative to standard, blood-pressure-lowering targets (systolic BP < 120 vs. <140 mm Hg). In this perspective, we discuss key questions and make recommendations for clinical practice and for clinical trials, following SPRINT-MIND. Future trials should embody cognitive endpoints appropriate to the participant group, ideally with adaptive designs that ensure robust answers for cognitive and cardiovascular endpoints. Reliable data from diverse populations, including the oldest-old (age > 80 years), will maximize external validity and global implementation of trial findings. New biomarkers will improve phenotyping to stratify patients to optimal treatments. Currently no antihypertensive drug class stands out for dementia risk reduction. Multi-domain interventions, incorporating lifestyle change (exercise, diet) alongside medications, may maximize global impact. Given the low cost and wide availability of antihypertensive drugs, intensive BP reduction may be a cost-effective means to reduce dementia risk in diverse, aging populations worldwide.

Association of Intensive vs Standard Blood Pressure Control With Regional Changes in Cerebral Small Vessel Disease Biomarkers: Post Hoc Secondary Analysis of the SPRINT MIND Randomized Clinical Trial

IMPORTANCE

Little is known about the associations of strict blood pressure (BP) control with microstructural changes in small vessel disease markers.

OBJECTIVE

To investigate the regional associations of intensive vs standard BP control with small vessel disease biomarkers, such as white matter lesions (WMLs), fractional anisotropy (FA), mean diffusivity (MD), and cerebral blood flow (CBF).

DESIGN, SETTING, AND PARTICIPANTS

The Systolic Blood Pressure Intervention Trial (SPRINT) is a multicenter randomized clinical trial that compared intensive systolic BP (SBP) control (SBP target <120 mm Hg) vs standard control (SBP target <140 mm Hg) among participants aged 50 years or older with hypertension and without diabetes or a history of stroke. The study began randomization on November 8, 2010, and stopped July 1, 2016, with a follow-up duration of approximately 4 years. A total of 670 and 458 participants completed brain magnetic resonance imaging at baseline and follow-up, respectively, and comprise the cohort for this post hoc analysis. Statistical analyses for this post hoc analysis were performed between August 2020 and October 2022.

INTERVENTIONS

At baseline, 355 participants received intensive SBP treatment and 315 participants received standard SBP treatment.

MAIN OUTCOMES AND MEASURES

The main outcomes were regional changes in WMLs, FA, MD (in white matter regions of interest), and CBF (in gray matter regions of interest).

RESULTS

At baseline, 355 participants (mean [SD] age, 67.7 [8.0] years; 200 men [56.3%]) received intensive BP treatment and 315 participants (mean [SD] age, 67.0 [8.4] years; 199 men [63.2%]) received standard BP treatment. Intensive treatment was associated with smaller mean increases in WML volume compared with standard treatment (644.5 mm3 vs 1258.1 mm3). The smaller mean increases were observed specifically in the deep white matter regions of the left anterior corona radiata (intensive treatment, 30.3 mm3 [95% CI, 16.0-44.5 mm3]; standard treatment, 80.5 mm3 [95% CI, 53.8-107.2 mm3]), left tapetum (intensive treatment, 11.8 mm3 [95% CI, 4.4-19.2 mm3]; standard treatment, 27.2 mm3 [95% CI, 19.4-35.0 mm3]), left superior fronto-occipital fasciculus (intensive treatment, 3.2 mm3 [95% CI, 0.7-5.8 mm3]; standard treatment, 9.4 mm3 [95% CI, 5.5-13.4 mm3]), left posterior corona radiata (intensive treatment, 26.0 mm3 [95% CI, 12.9-39.1 mm3]; standard treatment, 52.3 mm3 [95% CI, 34.8-69.8 mm3]), left splenium of the corpus callosum (intensive treatment, 45.4 mm3 [95% CI, 25.1-65.7 mm3]; standard treatment, 83.0 mm3 [95% CI, 58.7-107.2 mm3]), left posterior thalamic radiation (intensive treatment, 53.0 mm3 [95% CI, 29.8-76.2 mm3]; standard treatment, 106.9 mm3 [95% CI, 73.4-140.3 mm3]), and right posterior thalamic radiation (intensive treatment, 49.5 mm3 [95% CI, 24.3-74.7 mm3]; standard treatment, 102.6 mm3 [95% CI, 71.0-134.2 mm3]).

CONCLUSIONS AND RELEVANCE

This study suggests that intensive BP treatment, compared with standard treatment, was associated with a slower increase of WMLs, improved diffusion tensor imaging, and FA and CBF changes in several brain regions that represent vulnerable areas that may benefit from more strict BP control.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01206062.

Diastolic Blood Pressure and Intensive Blood Pressure Control on Cognitive Outcomes: Insights From the SPRINT MIND Trial

BACKGROUND

The potential benefits or harms of intensive systolic blood pressure (BP) control on cognitive function and cerebral blood flow in individuals with low diastolic blood pressure (DBP) remain unclear.

METHODS

We conducted a post hoc analysis of the SPRINT MIND (Systolic Blood Pressure Intervention Trial Memory and Cognition in Decreased Hypertension) that randomly assigned hypertensive participants to an intensive (<120 mm Hg; n=4278) or standard (<140 mm Hg; n=4385) systolic blood pressure target. We evaluated the effects of BP intervention on cognitive outcomes and cerebral blood flow across baseline DBP quartiles.

RESULTS

Participants in the intensive group had a lower incidence rate of probable dementia or mild cognitive impairment than those in the standard group, regardless of DBP quartiles. The hazard ratio of intensive versus standard target for probable dementia or mild cognitive impairment was 0.91 (95% CI, 0.73-1.12) in the lowest DBP quartile and 0.70 (95% CI, 0.48-1.02) in the highest DBP quartile, respectively, with an interaction P value of 0.24. Similar results were found for probable dementia (interaction P=0.06) and mild cognitive impairment (interaction P=0.80). The effect of intensive treatment on cerebral blood flow was not modified by baseline DBP either (interaction P=0.25). Even among participants within the lowest DBP quartile, intensive versus standard BP treatment resulted in an increasing trend of annualized change in cerebral blood flow (+0.26 [95% CI, -0.72 to 1.24] mL/[100 g·min]).

CONCLUSIONS

Intensive BP control did not appear to have a detrimental effect on cognitive outcomes and cerebral perfusion in patients with low baseline DBP.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT01206062.

Influence of Baseline Diastolic Blood Pressure on the Effects of Systolic Blood Pressure Lowering on Cognitive Function in Type 2 Diabetes Mellitus

BACKGROUND

Lowering of systolic blood pressure (SBP) in patients with low diastolic blood pressure (DBP), can further lower DBP. This can potentially decrease cerebral perfusion and cognition. We examined the influence of baseline DBP on the effect of lowering SBP on cognition.

METHODS

This is a post hoc analysis of the Memory in Diabetes (MIND) substudy (N = 1,430) of the Action to Control Cardiovascular Risk in Diabetes (ACCORD) study (NCT00000620). Standard neuropsychological tests (Digit Symbol Substitution Test [DSST], Mini-Mental State Examination [MMSE], Rey Auditory Verbal Learning Test [RAVLT], and Stroop test) were performed at baseline and months 20 and 40. We compared the effects of intensive (goal SBP <120 mm Hg) vs. standard (goal SBP <140 mm Hg) SBP control on the changes in the 4 test scores from baseline to the averages of months 20 and 40 across the range of baseline DBP using cubic spline terms.

RESULTS

Mean age was 63 ± 6 years, 55% were women and 66% White. Participates with lower baseline DBP were older, had more cardiovascular events and a longer duration of diabetes. There was no difference in the change in DSST (-0.22; 95% CI -0.97, 0.52), MMSE (-0.14; 95% CI -0.34, 0.06), RAVLT (-0.12; 95% CI -0.29, 0.06), and Stroop interference (-0.47; 95% CI -1.76, 0.82) in the intensive vs. standard SBP intervention. There was no interaction between baseline DBP and change in scores with the SBP intervention.

CONCLUSIONS

Intensive SBP reduction does not adversely affect cognition, even in those with low baseline DBP.

Cerebral hemodynamic effects of early blood pressure lowering after TIA and stroke in patients with carotid stenosis

BACKGROUND

Effects of early blood pressure (BP) lowering on cerebral perfusion in patients with moderate/severe occlusive carotid disease after transient ischemic attack (TIA) and non-disabling stroke are uncertain.

AIMS

We aimed to evaluate the changes in transcranial Doppler (TCD) indices in patients undergoing blood pressure lowering soon after TIA/non-disabling stroke.

METHODS

Consecutive eligible patients (1 November 2011 to 30 October 2018) attending a rapid-access clinic with TIA/non-disabling stroke underwent telemetric home blood pressure monitoring (HBPM) for 1 month and middle cerebral artery velocities measurements ipsilateral to carotid stenosis on TCD ultrasound in the acute setting and at 1 month. Hypertensive patients (HBPM ⩾ 135/85) underwent intensive BP-lowering guided by HBPM unless they had bilateral severe occlusive disease (⩾ 70%). Changes in BP and TCD parameters were compared in patients with extracranial moderate/severe carotid stenosis (between 50% and occlusion) versus those with no or mild (< 50%) stenosis.

RESULTS

Of 764 patients with repeated TCD measures, 42 had moderate/severe extracranial carotid stenosis without bilateral severe occlusive disease. HBPM was reduced from baseline to 1 month in hypertensive patients both with versus without moderate/severe carotid stenosis (-12.44/15.99 vs -13.2/12.2 mmHg, respectively, p-difference = 0.82), and changes in TCD velocities (4.69/14.94 vs 2.69/13.86 cm/s, respectively, p-difference = 0.52 for peak systolic velocity and 0.33/7.06 vs 1.75/6.84 cm/s, p-difference = 0.34 for end-diastolic velocity) were also similar, with no evidence of greater hemodynamic compromise in patients with stenosis/occlusion.

CONCLUSION

There was no evidence of worsening of TCD hemodynamic indices in patients with moderate/severe occlusive carotid disease treated with BP-lowering soon after TIA/non-disabling stroke, suggesting that antihypertensive treatment in this group of patients is safe in the acute setting of TIA clinics.

The PASTIS trial: Testing tadalafil for possible use in vascular cognitive impairment

INTRODUCTION

There are few randomized clinical trials in vascular cognitive impairment (VCI). This trial tested the hypothesis that the PDE5 inhibitor tadalafil, a widely used vasodilator, increases cerebral blood flow (CBF) in older people with symptomatic small vessel disease, the main cause of VCI.

METHODS

In a double-blind, placebo-controlled, cross-over trial, participants received tadalafil (20 mg) and placebo on two visits ≥7 days apart (randomized to order of treatment). The primary endpoint, change in subcortical CBF, was measured by arterial spin labelling.

RESULTS

Tadalafil increased CBF non-significantly in all subcortical areas (N = 55, age: 66.8 (8.6) years) with greatest treatment effect within white matter hyperintensities (+9.8%, P = .0960). There were incidental treatment effects on systolic and diastolic blood pressure (-7.8, -4.9 mmHg; P < .001). No serious adverse events were observed.

DISCUSSION

This trial did not identify a significant treatment effect of single-administration tadalafil on subcortical CBF. To detect treatment effects may require different dosing regimens.

Orthostatic Hypotension in Hypertensive Adults: Harry Goldblatt Award for Early Career Investigators 2021

Orthostatic hypotension affects roughly 10% of individuals with hypertension and is associated with several adverse health outcomes, including dementia, cardiovascular disease, stroke, and death. Among adults with hypertension, orthostatic hypotension has also been shown to predict patterns of blood pressure dysregulation that may not be appreciated in the office setting, including nocturnal nondipping. Individuals with uncontrolled hypertension are at particular risk of orthostatic hypotension and may meet diagnostic criteria for the condition with a smaller relative reduction in blood pressure compared with normotensive individuals. Antihypertensive medications are commonly de-prescribed to address orthostatic hypotension; however, this approach may worsen supine or seated hypertension, which may be an important driver of adverse events in this population. There is significant variability between guidelines for the diagnosis of orthostatic hypotension with regards to timing and position of blood pressure measurements. Clinically relevant orthostatic hypotension may be missed when standing measurements are delayed or when taken after a seated rather than supine position. The treatment of orthostatic hypotension in patients with hypertension poses a significant management challenge for clinicians; however, recent evidence suggests that intensive blood pressure control may reduce the risk of orthostatic hypotension. A detailed characterization of blood pressure variability is essential to tailoring a treatment plan and can be accomplished using both in-office and out-of-office monitoring.

Effects of intensive blood pressure control on cardiovascular and cognitive outcomes in patients with atrial fibrillation: insights from the SPRINT trial

AIMS

Patients with atrial fibrillation (AF) have an increased risk of cardiovascular events and dementia, even if anticoagulated. Hypertension is highly prevalent in AF population; however, the optimal blood pressure (BP) target for AF patients remains unknown.

METHODS AND RESULTS

We conducted subgroup analysis of the Systolic Blood Pressure Intervention Trial (SPRINT) to examine whether AF modified the treatment effects of intensive BP control on cardiovascular and cognitive outcomes using Cox proportional hazards regression and likelihood ratio tests. Among 9361 randomized participants, 778 (8.3%) had baseline AF, and 695 (89.3%) completed at least one follow-up cognitive assessment. Intensive BP control reduced the similar relative risk of cardiovascular events irrespective of the presence of AF, with all interaction P-values > 0.05. Patients with AF experienced a greater absolute risk reduction in the composite primary cardiovascular outcome (12.3 vs. 5.6 events per 1000 person-years) with intensive treatment, compared with those without AF. However, intensive BP control increased the risk of probable dementia in patients with AF [hazard ratio (HR), 2.22; 95% confidence interval (CI), 1.03-4.80], while reducing the dementia risk in patients without AF (HR, 0.75; 95% CI, 0.60-0.95; P = 0.009 for interaction). There were no significant interactions between the presence of AF and intensive BP treatment for mild cognitive impairment.

CONCLUSION

Patients with AF experienced greater absolute cardiovascular benefits with intensive BP treatment, but may need to be cautious of an increased risk of dementia. This post hoc analysis should be considered as hypothesis generating and merit further study.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifier: NCT01206062.

Daily blood pressure profile and blood-brain barrier permeability in patients with cerebral small vessel disease

Cerebral small vessel disease (CSVD) plays an important role in cognitive impairment, stroke, disability, and death. Hypertension is the main risk factor for CSVD. The use of antihypertensive therapy has not resulted in the expected decrease in CSVD complications, which may be related to the underestimation of significance of daily blood pressure profile for blood–brain barrier (BBB) permeability. 53 patients with CSVD of varying severity (mean age 60.08 ± 6.8 years, 69.8% women, subjects with treated long-standing hypertension vs. normotensive subjects − 84.8% vs. 15.2%) and 17 healthy volunteers underwent ambulatory blood pressure monitoring (ABPM) and MRI, including T1-weighted dynamic contrast-enhanced magnetic resonance imaging for assessing BBB permeability. Most of ABPM parameters in CSVD patients did not differ from controls, but were associated with the severity of white matter hyperintensity (WMH) and the total CSVD score. BBB permeability in normal-appearing white matter (NAWM) and grey matter (GM) was significantly higher in CSVD patients, and the severity of BBB permeability remained similar in patients with different stages of WMH. Among BBB permeability parameters, the area under the curve, corresponding to an increase in the contrast transit time in NAWM, had the greatest number of correlations with deviations of ABPM parameters. BBB permeability in CSVD is a universal mechanism of NAWM and GM damage associated with a slight increase in ABPM parameters. It is obvious that the treatment of hypertension in patients with not severe WMH should be more aggressive and carried out under the control of ABPM.

Effect of Antihypertensive Treatment on Cerebral Blood Flow in Older Adults: a Systematic Review and Meta-Analysis

BACKGROUND

In older age, the benefits of antihypertensive treatment (AHT) become less evident, with greater associated risk. Of particular concern is compromising cerebral blood flow (CBF), especially in those with cognitive impairment.

METHODS

We created a synthesis of the published evidence by searching multiple electronic databases from 1970 to May 2021. Included studies had participants with mean age ≥50 years, hypertension or cognitive impairment, and assessed CBF before and after initiating AHT. Two authors independently determined eligibility and extracted data. Study quality was assessed using The Risk of Bias in Nonrandomized Studies of Interventions tool. We summarized study characteristics (qualitative synthesis) and performed random-effects meta-analyses (quantitative synthesis).

RESULTS

Thirty-two studies (total n=1306) were included, of which 23 were eligible for meta-analysis. In line with the qualitative synthesis, the meta-analysis indicated no effect of AHT initiation on CBF (standardized mean difference, 0.08 [95% CI, -0.07 to 0.22]; P=0.31, I2=42%). This was consistent across subgroups of acute versus chronic AHT, drug class, study design, and CBF measurement. Subgroups by age demonstrated an increase in CBF after AHT in those aged >70 years (standardized mean difference, 4.15 [95% CI, 0.16-8.15]; P=0.04, I2=42%), but not in those aged 50 to 65 and 65 to 70 years (standardized mean difference, 0.18 [95% CI,-2.02 to 2.38]; P=0.87, I2=49%; standardized mean difference, 1.22 [95% CI, -0.45 to 2.88]; P=0.15, I2=68%). Overall, risk of bias was moderate-to-high and quality of evidence (Grading of Recommendations Assessment, Development and Evaluation) was very low, reflecting the observational nature of the data.

CONCLUSIONS

Accepting the observed limitations, current evidence does not suggest a harmful effect of AHT on CBF. Concerns over CBF should not preclude treatment of hypertension.

Association of Intensive vs Standard Blood Pressure Control With Cerebral Blood Flow: Secondary Analysis of the SPRINT MIND Randomized Clinical Trial

IMPORTANCE

Antihypertensive treatments benefit cerebrovascular health and cognitive function in patients with hypertension, but it is uncertain whether an intensive blood pressure target leads to potentially harmful cerebral hypoperfusion.

OBJECTIVE

To investigate the association of intensive systolic blood pressure (SBP) control vs standard control with whole-brain cerebral blood flow (CBF).

DESIGN, SETTING, AND PARTICIPANTS

This substudy of the Systolic Blood Pressure Intervention Trial (SPRINT) randomized clinical trial compared the efficacy of 2 different blood pressure-lowering strategies with longitudinal brain magnetic resonance imaging (MRI) including arterial spin labeled perfusion imaging to quantify CBF. A total of 1267 adults 50 years or older with hypertension and increased cardiovascular risk but free of diabetes or dementia were screened for the SPRINT substudy from 6 sites in the US. Randomization began in November 2010 with final follow-up MRI in July 2016. Analyses were performed from September 2020 through December 2021.

INTERVENTIONS

Study participants with baseline CBF measures were randomized to an intensive SBP target less than 120 mm Hg or standard SBP target less than 140 mm Hg.

MAIN OUTCOMES AND MEASURES

The primary outcome was change in whole-brain CBF from baseline. Secondary outcomes were change in gray matter, white matter, and periventricular white matter CBF.

RESULTS

Among 547 participants with CBF measured at baseline, the mean (SD) age was 67.5 (8.1) years and 219 (40.0%) were women; 315 completed follow-up MRI at a median (IQR) of 4.0 (3.7-4.1) years after randomization. Mean whole-brain CBF increased from 38.90 to 40.36 (difference, 1.46 [95% CI, 0.08-2.83]) mL/100 g/min in the intensive treatment group, with no mean increase in the standard treatment group (37.96 to 37.12; difference, -0.84 [95% CI, -2.30 to 0.61] mL/100 g/min; between-group difference, 2.30 [95% CI, 0.30-4.30; P = .02]). Gray, white, and periventricular white matter CBF showed similar changes. The association of intensive vs standard treatment with CBF was generally similar across subgroups defined by age, sex, race, chronic kidney disease, SBP, orthostatic hypotension, and frailty, with the exception of an indication of larger mean increases in CBF associated with intensive treatment among participants with a history of cardiovascular disease (interaction P = .05).

CONCLUSIONS AND RELEVANCE

Intensive vs standard antihypertensive treatment was associated with increased, rather than decreased, cerebral perfusion, most notably in participants with a history of cardiovascular disease.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01206062.

Potential risk factors of persistent postural-perceptual dizziness: a pilot study

BACKGROUND

Persistent postural-perceptual dizziness (PPPD) unifies the main characteristics of chronic subjective dizziness, visual vertigo and related diseases, which is a common chronic disease in neurology. At present, the pathology of PPPD is not fully understood.

OBJECTIVE

In this single-center retrospective case series review, we aim to investigate the potential risk factors of PPPD.

METHODS

Eighty inpatients diagnosed with PPPD were recruited with 81 apparently healthy controls. Patient-specific clinico-radiological data were collected from both groups. Conditions of hypertension, diabetes, smoking, and drinking were derived from medical history. Blood test results were recorded including total cholesterol, triglyceride, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, fibrinogen, vitamin B12, folic acid, total cholesterol, triglyceride, and folate level. The subjects were examined by carotid artery CTA and cranial MRI, and the imaging findings of carotid atherosclerosis (CAS), white matter hyperintensities (WMHs) and lacunar infarction (LI) were recorded. Binary logistic regression analysis was used to investigate the difference between the case and control groups. Significance was defined as p value less than 0.05.

RESULTS

The prevalence rate of hypertension in the case group was significantly higher than that in the control group, and the detection rates of CAS, WMHs, and LI in the case group were significantly higher than those in the control group (p < 0.05 for all).

CONCLUSION

Hypertension, CAS, WMHs, and LI are associated with PPPD, which may be potential risk factors for its development.

Regulation of cerebral blood flow in humans: physiology and clinical implications of autoregulation

Brain function critically depends on a close matching between metabolic demands, appropriate delivery of oxygen and nutrients, and removal of cellular waste. This matching requires continuous regulation of cerebral blood flow (CBF), which can be categorized into four broad topics: 1) autoregulation, which describes the response of the cerebrovasculature to changes in perfusion pressure; 2) vascular reactivity to vasoactive stimuli [including carbon dioxide (CO2)]; 3) neurovascular coupling (NVC), i.e., the CBF response to local changes in neural activity (often standardized cognitive stimuli in humans); and 4) endothelium-dependent responses. This review focuses primarily on autoregulation and its clinical implications. To place autoregulation in a more precise context, and to better understand integrated approaches in the cerebral circulation, we also briefly address reactivity to CO2 and NVC. In addition to our focus on effects of perfusion pressure (or blood pressure), we describe the impact of select stimuli on regulation of CBF (i.e., arterial blood gases, cerebral metabolism, neural mechanisms, and specific vascular cells), the interrelationships between these stimuli, and implications for regulation of CBF at the level of large arteries and the microcirculation. We review clinical implications of autoregulation in aging, hypertension, stroke, mild cognitive impairment, anesthesia, and dementias. Finally, we discuss autoregulation in the context of common daily physiological challenges, including changes in posture (e.g., orthostatic hypotension, syncope) and physical activity.

Age-specific cerebral haemodynamic effects of early blood pressure lowering after transient ischaemic attack and non-disabling stroke

INTRODUCTION

There is limited knowledge of the effects of blood pressure (BP) lowering on cerebral haemodynamics after transient ischaemic attack (TIA) and non-disabling stroke, particularly at older ages. We aimed to evaluate changes in transcranial Doppler (TCD) haemodynamic indices in patients undergoing early blood pressure lowering after TIA/non-disabling stroke, irrespective of age.

PATIENTS AND METHODS

Among consecutive eligible patients attending a rapid-access clinic with suspected TIA/non-disabling stroke and no evidence of extra/intracranial stenosis, hypertensive ones underwent intensive BP-lowering guided by daily home telemetric blood pressure monitoring (HBPM). Clinic-based BP, HBPM, End-tidal CO2 and bilateral middle cerebral artery (MCA) velocity on TCD were compared in the acute setting versus one-month follow-up; changes were stratified by baseline hypertension (clinic-BP≥140/90) and by age (<65, 65-79 and ≥80).

RESULTS

In 697 patients with repeated TCD measures, mean/SD baseline systolic-BP (145.0/21.3 mmHg) was reduced by an average of 11.3/19.9 mmHg (p < 0.0001) at one-month (133.7/17.4 mmHg), driven by patients hypertensive at baseline (systolic-BP change = -19.0/19.2 mmHg, p < 0.001; vs -0.5/15.4, p = 0.62 in normotensives). Compared with baseline, a significant change was observed at one-month only in mean/SD MCA end diastolic velocity (EDV) (0.77/7.26 cm/s, p = 0.005) and in resistance index (RI) (-0.005/0.051, p = 0.016), driven by hypertensive patients (mean/SD EDV change: 1.145/6.96 cm/s p = 0.001, RI change -0.007/0.06, p = 0.014). Findings were similar at all ages (EDV change - ptrend=0.357; RI change - ptrend=0.225), including 117 patients aged ≥80. EDV and RI changes were largest in 100 patients with clinic systolic-BP decrease ≥30 mmHg (mean/SD EDV change = 2.49/7.47 cm/s, p = 0.001; RI change -0.024/0.063, p < 0.0001).

CONCLUSION

There was no evidence of worsening of TCD haemodynamic indices associated with BP-lowering soon after TIA/non-disabling stroke, irrespective of age and degree of BP reduction. In fact, EDV increase and RI decrease observed after treatment of hypertensive patients suggest a decrease in distal vascular resistance.

Aerobic exercise improves hippocampal blood flow for hypertensive Apolipoprotein E4 carriers

Cerebrovascular dysfunction likely contributes causally to Alzheimer's disease (AD). The strongest genetic risk factor for late-onset AD, Apolipoprotein E4 (APOE4), may act synergistically with vascular risk to cause dementia. Therefore, interventions that improve vascular health, such as exercise, may be particularly beneficial for APOE4 carriers. We assigned cognitively normal adults (65-87 years) to an aerobic exercise intervention or education only. Arterial spin labeling MRI measured hippocampal blood flow (HBF) before and after the 52-week intervention. We selected participants with hypertension at enrollment (n = 44). For APOE4 carriers, change in HBF (ΔHBF) was significantly (p = 0.006) higher for participants in the exercise intervention (4.09 mL/100g/min) than the control group (-2.08 mL/100g/min). There was no difference in ΔHBF between the control (-0.32 mL/100g/min) and exercise (-0.54 mL/100g/min) groups for non-carriers (p = 0.918). Additionally, a multiple regression showed an interaction between change in systolic blood pressure (ΔSBP) and APOE4 carrier status on ΔHBF (p = 0.035), with reductions in SBP increasing HBF for APOE4 carriers only. Aerobic exercise improved HBF for hypertensive APOE4 carriers only. Additionally, only APOE4 carriers exhibited an inverse relationship between ΔSBP and ΔHBF. This suggests exercise interventions, particularly those that lower SBP, may be beneficial for individuals at highest genetic risk of AD.ClinicalTrials.gov Identifier: NCT02000583.

Urinary sodium and potassium excretion and cerebrovascular health: a multimodal imaging study

PURPOSE

Dietary sodium and potassium intake are associated with stroke, but the potential mechanisms are unclear. We aimed to study the association between sodium and potassium intake and subclinical cerebrovascular health in hypertensive older males using multimodal magnetic resonance imaging.

METHODS

A total of 189 hypertensive male subjects without previous cardiovascular or cerebrovascular disease were included. Daily urinary sodium and potassium excretion were estimated from a fasting spot urine sample using a formula approach. A dedicated cerebrovascular health imaging protocol including vessel wall imaging, angiography, arterial spin labeling imaging and T2-weighted fluid-attenuated inversion recovery imaging was performed to study intracranial atherosclerosis, vascular rarefaction (defined as fewer discernible vessels on angiography), brain perfusion and small vessel disease, respectively.

RESULTS

The mean age was 64.9 (± 7.2) years. The average daily urinary and potassium excretion was 4.7 (± 1.4) g/L and 2.1 (± 0.5) g/L, respectively. Increased urinary sodium excretion was associated with decreased cerebral blood flow and elevated urinary potassium excretion was associated with reduced prevalence of intracranial plaque. The associations remained significant after adjusting for covariates, even including blood pressure control. Quadratic regression analysis indicated a marginally significant U-shaped association between urinary sodium intake and white matter hyperintensity, which lost significance in fully adjusted models. No significant association of urinary sodium and potassium excretion with other cerebrovascular health measures was noted.

CONCLUSION

We concluded that in hypertensive older males without overt cardiovascular disease, increased sodium intake and reduced potassium intake are associated with impaired subclinical cerebrovascular health.

Is orthostatic hypotension and co-existing supine and seated hypertension associated with future falls in community-dwelling older adults? Results from The Irish Longitudinal Study on Ageing (TILDA)

Orthostatic hypotension (OH) often co-exists with hypertension. As increasing age affects baroreflex sensitivity, it loses its ability to reduce blood pressure when lying down. Therefore, supine hypertension may be an important indicator of baroreflex function. This study examines (i) the association between OH and future falls in community-dwelling older adults and (ii) if these associations persist in those with co-existing OH and baseline hypertension, measured supine and seated. Data from 1500 community-dwelling adults aged ≥65 years from The Irish Longitudinal Study on Ageing (TILDA) were used. Continuous beat-to-beat blood pressure was measured using digital photoplethysmography during an active stand procedure with OH defined as a drop in systolic blood pressure (SBP) ≥20 mmHg and/or ≥10 mm Hg in diastolic blood pressure (DBP) within 3 minutes of standing. OH at 40 seconds (OH40) was used as a marker of impaired early stabilisation and OH sustained over the second minute (sustained OH) was used to indicate a more persistent deficit, similar to traditional OH definitions. Seated and supine hypertension were defined as SBP ≥140 mm Hg or DBP ≥90 mm Hg. Modified Poisson models were used to estimate relative risk of falls (recurrent, injurious, unexplained) and syncope occurring over four year follow-up. OH40 was independently associated with recurrent (RR = 1.30, 95% CI = 1.02,1.65), injurious (RR = 1.43, 95% CI = 1.13,1.79) and unexplained falls (RR = 1.55, 95% CI = 1.13,2.13). Sustained OH was associated with injurious (RR = 1.55, 95% CI = 1.18,2.05) and unexplained falls (RR = 1.63, 95% CI = 1.06,2.50). OH and co-existing hypertension was associated with all falls outcomes but effect sizes were consistently larger with seated versus supine hypertension. OH, particularly when co-existing with hypertension, was independently associated with increased risk of future falls. Stronger effect sizes were observed with seated versus supine hypertension. This supports previous findings and highlights the importance of assessing orthostatic blood pressure behaviour in older adults at risk of falls and with hypertension. Observed associations may reflect underlying comorbidities, reduced cerebral perfusion or presence of white matter hyperintensities.

Cardiovascular outcomes in patients at high cardiovascular risk with previous myocardial infarction or stroke

BACKGROUND

Guidelines recommend to start blood pressure (BP)-lowering drugs also according to cardiovascular risk including history of cardiovascular events. We hypothesized that in patients with a history of myocardial infarction (MI), stroke, both or none of those, the index events predict the next event and have different SBP risk associations to different cardiovascular outcomes.

DESIGN AND MEASUREMENTS

In this pooled posthoc, nonprespecified analysis, we assessed outcome data from high-risk patients aged 55 years or older with a history of cardiovascular events or proven cardiovascular disease, randomized to the Ongoing Telmisartan Alone and in Combination with Ramipril Global Endpoint Trial and to Telmisartan Randomized Assessment Study in ACE Intolerant Subjects with Cardiovascular Disease Trial investigating telmisartan, ramipril and their combination with a median follow-up of 56 months. Standardized office BP was measured every 6 months. Associations of mean achieved BP on treatment were investigated on MI, stroke and cardiovascular death. We identified patients with previous MI (N = 13 487), stroke (N = 4985), both (N = 1509) or none (N = 10 956) of these index events. Analyses were done by Cox regression, analysis of variance and Chi2-test. 30 937 patients with complete data were enrolled between 1 December 2001 and 31 July 2003, and followed until 31 July 2008. Data of both trials were pooled as the outcomes were similar.

RESULTS

Patients with MI as index event had a higher risk to experience a second MI [hazard ratio 1.42 (confidence interval (CI) 1.20-1.69), P < 0.0001] compared with patients with no events but no increased risk for a stroke as a next event [hazard ratio 0.95 (CI 0.73-1.23), n.s.]. The risk was roughly doubled when they had both, MI and stroke before [hazard ratio 2.07 (CI 1.58-2.71), P < 0.0001]. Patients with a stroke history had a roughly three-fold higher likelihood to experience a second stroke [hazard ratio 2.89 (CI 2.37-3.53) P < 0.0001] but not MI [hazard ratio 1.07 (CI 0.88-1.32), n.s.]. Both types of index events increased roughly three-fold the risk of a second stroke compared with no previous events. The SBP-risk relationship was not meaningfully altered by the event history. After MI and stroke the risk for subsequent events and cardiovascular death was increased over the whole SBP spectrum. A J-shape relationship between BP and outcome was only observed for cardiovascular death.

CONCLUSION

Previous MI and previous stroke are associated with increased risk for the same event in the future, independent of achieved SBP. Thus, secondary prevention may also be chosen according to the event history of patients.

CLINICAL TRIAL REGISTRATION

http://clinicaltrials.gov. Unique identifier: NCT00153101.

Effect of anesthesia induction on cerebral tissue oxygen saturation in hypertensive patients: an observational study

OBJECTIVE

In hypertensive patients, the autoregulation curve shifts rightward, making these patients more sensitive than normotensive individuals to hypotension. Hypotension following the induction of anesthesia has been studied in normotensive patients to determine its effects on brain tissue oxygenation, but not enough studies have examined the effect of hypotension on brain oxygenation in hypertensive patients. The current study aimed to use near-infrared spectroscopy to evaluate brain tissue oxygen saturation after the induction of anesthesia in hypertensive patients, who may have impaired brain tissue oxygen saturation.

METHODS

The study included a total of 200 patients aged > 18 years old with ASA I-III. Measurements were taken while the patient was breathing room air, after the induction of anesthesia, when the lash reflex had disappeared following the induction of anesthesia, after intubation, and in the 5th, 10th, and 15th minutes of surgery. The patients were divided into nonhypertensive and hypertensive groups.

RESULTS

There was a significant difference in age between the groups (p = 0.000). No correlation was found between cerebral tissue oxygen saturation and age (r = 0.015, p = 0.596). Anesthesia induction was observed to decrease mean arterial blood pressure in both groups (p = 0.000). Given these changes, there was no significant difference in brain tissue oxygen saturation between the nonhypertensive and hypertensive groups (p > 0.05).

CONCLUSION

There was no difference between hypertensive and normotensive groups in terms of the change rates in cSO₂ values. However, there was a difference between the groups in terms of cSO₂ values.

Blood Pressure Variability and Dementia: A State-of-the-Art Review

Accumulating evidence demonstrates that blood pressure variability (BPV) may contribute to target organ damage, causing coronary heart disease, stroke, and renal disease independent of the level of blood pressure (BP). Several lines of evidence have also linked increased BPV to a higher risk of cognitive decline and incident dementia. The estimated number of dementia cases worldwide is nearly 50 million, and this number continues to grow with increasing life expectancy. Because there is no effective treatment to modify the course of dementia, targeting modifiable vascular factors continues as a top priority for dementia prevention. A clear understanding of the role of BPV in dementia may shed light on the etiology, early prevention, and novel therapeutic targets of dementia, and has therefore gained substantial attention from researchers and clinicians. This review summarizes state-of-art evidence on the relationship between BPV and dementia, with a specific focus on the epidemiological evidence, the underlying mechanisms, and potential intervention strategies. We also discuss challenges and opportunities for future research to facilitate optimal BP management and the clinical translation of BPV for the risk assessment and prevention of dementia.

Effect of Perindopril/Indapamide on Cerebral Blood Flow in Middle-Aged, Treatment-Naïve Patients with Hypertension

INTRODUCTION

The relationship between blood pressure (BP) and cerebral blood flow (CBF) is not fully understood. This study evaluated the impact of a perindopril arginine/indapamide (Pa/I) single-pill combination (SPC) on CBF in middle-aged patients.

METHODS

A total of 22 treatment-naïve patients with essential hypertension and at least one hypertension-mediated organ damage and 41 healthy controls were enrolled. At baseline, all participants underwent brain magnetic resonance imaging (MRI); patients with hypertension underwent an additional MRI at end of follow-up. Arterial spin labeling (ASL) was used to calculate CBF in the frontal lobe cortical plate. Patients with hypertension received once-daily Pa/I 5 mg/1.25 mg SPC, which could be increased to Pa/I 10 mg/2.5 mg at 2 weeks if necessary. Patients with hypertension underwent 24-h ambulatory BP monitoring (ABPM) at baseline and end of follow-up.

RESULTS

Mean baseline BP values were 146.2/93.1 and 119.1/76.1 mmHg in the hypertension and control groups, respectively. Patients with hypertension had significantly (p < 0.001) lower CBF in the cortical plate of both left (36.2 ± 8.3 vs. 45.3 ± 3.5 ml/100 g/min) and right (37.9 ± 7.9 vs. 45.8 ± 3.2 ml/100 g/min) frontal lobes compared to normotensive controls. At the end of follow-up, there was a statistically significant (p < 0.001) increase in CBF in the cortical plate of both left (from 36.2 ± 8.3 to 47.5 ± 9.8 ml/100 g/min) and right frontal lobes (from 37.9 ± 7.9 to 47.4 ± 10.1 ml/100 g/min) compared to baseline. No significant difference was found between end of follow-up CBF levels in frontal lobes of patients with hypertension and those of healthy controls at baseline. Office BP decreased by 24.2/15.5 mmHg and 24-h ABPM from 145.5/95.3 to 120.8/79.3 mmHg.

CONCLUSION

In middle-aged, treatment-naïve patients with hypertension, Pa/I SPC was associated with increased CBF in the cortical plate of the frontal lobes, which achieved levels of normotensive controls. The increase in CBF had no clear association with observed BP changes.

REGISTRATION NUMBER

ISRCTN67799751.

Uncontrolled hypertension associates with subclinical cerebrovascular health globally: a multimodal imaging study

OBJECTIVES

The study aimed to analyze the association between hypertension control and subclinical cerebrovascular health using a comprehensive multimodal imaging approach.

METHODS

The study included 200 hypertensive older males without previous cardiovascular diseases. Clinic blood pressure (BP) was measured using a standard approach. Cerebrovascular health was evaluated using magnetic resonance imaging in the following four aspects: Intracranial atherosclerosis as determined by vessel wall imaging; Vascular rarefaction (defined as less discernible vessels on angiography) was evaluated using a custom-developed technique. Cerebral blood flow (CBF) and white matter hyperintensity (WMH) were assessed using arterial spin-labeling imaging and fluid-attenuated inversion recovery imaging, respectively.

RESULTS

A total of 189 subjects had MRI scans. The mean age was 64.9 (± 7.2) years. For intracranial atherosclerosis, there was a significant association between uncontrolled hypertension and presence of intracranial plaque. When systolic and diastolic BP were analyzed separately, the association remained significant for both. For vascular rarefaction, uncontrolled hypertension was associated with less discernible vessel branches or shorter vessel length on angiography. Further analysis revealed that this is due to uncontrolled diastolic BP, but not uncontrolled systolic BP. There was an association between uncontrolled hypertension and reduced CBF, which was also mainly driven by uncontrolled diastolic BP. We also found that uncontrolled diastolic BP, but not uncontrolled systolic BP, was associated with increased WMH volume.

CONCLUSIONS

Uncontrolled hypertension was associated with subclinical cerebrovascular injury globally, with both small and medium-to-large arteries being affected.

KEY POINTS

• In this study, we leveraged the advantage of a series of cutting-edge MR imaging and analysis techniques and found uncontrolled hypertension is associated with subclinical globally compromised cerebrovascular health. • The detrimental consequences of uncontrolled BP affect not only the small vessels but also the medium-to-large arteries, and uncontrolled systolic and diastolic BP are both independently associated with certain types of cerebrovascular injury. • Our data suggest that cerebrovascular health is impaired globally in uncontrolled hypertension before the onset of stroke.

Prevention and Treatment of Alzheimer's Disease: Biological Mechanisms of Exercise

Alzheimer's disease (AD) is the most common form of dementia. With an aging population and no disease modifying treatments available, AD is quickly becoming a global pandemic. A substantial body of research indicates that lifestyle behaviors contribute to the development of AD, and that it may be worthwhile to approach AD like other chronic diseases such as cardiovascular disease, in which prevention is paramount. Exercise is an important lifestyle behavior that may influence the course and pathology of AD, but the biological mechanisms underpinning these effects remain unclear. This review focuses on how exercise can modify four possible mechanisms which are involved with the pathology of AD: oxidative stress, inflammation, peripheral organ and metabolic health, and direct interaction with AD pathology. Exercise is just one of many lifestyle behaviors that may assist in preventing AD, but understanding the systemic and neurobiological mechanisms by which exercise affects AD could help guide the development of novel pharmaceutical agents and non-pharmacological personalized lifestyle interventions for at-risk populations.

Association of blood pressure with cognitive function at midlife: a Mendelian randomization study

BACKGROUND

Whether high blood pressure has a causal effect on cognitive function as early as middle age is unclear. We investigated whether high blood pressure (BP) causally impairs cognitive function at midlife using Mendelian Randomization (MR).

METHODS

We applied a two-sample MR approach to investigate the causal relationship between BP and midlife cognitive performance measured by the Digit Symbol Substitution Test (DSST), Rey Auditory Verbal Learning Test (RAVLT), and Stroop Interference test. We used a total of 109 genetic polymorphisms with established associations with BP as instrumental variables and estimated gene-cognitive function association in 1369 middle-aged adults (Mean age (SD): 50.8 (3.3), 54.0% women) from the CARDIA study.

RESULTS

A 10 mmHg increment in genetically-predicted systolic, diastolic, or pulse pressure was associated with a 4.9 to 7.7-point lower DSST score (P = 0.002, SBP; P = 0.005, DBP and P = 0.008, PP), while a 10 mmHg increment in genetically-predicted SBP was associated with a 0.7 point lower RAVLT and a 2.3 point higher Stroop (P = 0.046 and 0.011, respectively).

CONCLUSIONS

This MR analysis shows that high BP, especially SBP, is causally associated with poorer processing speed, verbal memory, and executive function during midlife. These findings emphasize the need for further investigation of the role and mechanisms of BP dysregulation on cognitive health in middle age and perhaps, more broadly, across the lifespan.

Cerebrovascular function in hypertension: Does high blood pressure make you old?

The majority of individuals over an age of 60 have hypertension. Elevated blood pressure and older age are associated with very similar changes in brain structure and function. We review the parallel brain changes associated with increasing age and blood pressure. This review focuses on joint associations of aging and elevated blood pressure with neuropsychological function, regional cerebral blood flow responses to cognitive and metabolic challenges, white matter disruptions, grey matter volume, cortical thinning, and neurovascular coupling. Treatment of hypertension ameliorates many of these changes but fails to reverse them. Treatment of hypertension itself appears more successful with better initial brain function. We show evidence that sympathetic and renal influences known to increase blood pressure also impact brain integrity. Possible central mechanisms contributing to the course of hypertension and aging are then suggested. An emphasis is placed on psychologically relevant factors: stress, cardiovascular reactions to stress, and diet/obesity. The contribution of some of these factors to biological aging remains unclear and may provide a starting point for defining the independent and interacting effects of aging and increasing blood pressure on the brain.

Nitroglycerin Is Not Associated with Improved Cerebral Perfusion in Acute Ischemic Stroke

OBJECTIVE

The study was conducted to test the hypothesis that nitroglycerin (NTG) increases cerebral perfusion focally and globally in acute ischemic stroke patients, using serial perfusion-weighted imaging (PWI) magnetic resonance imaging measurements.

PATIENTS AND METHODS

Thirty-five patients underwent PWI immediately before and 72 h after administration of a transdermal NTG patch or no treatment. Patients with baseline mean arterial pressure (MAP) > 100 mmHg (NTG group, n = 20) were treated with transdermal NTG (0.2 mg/h) for 72 h, without a nitrate-free interval. Patients with MAP ≤ 100 mmHg (untreated group, n = 15) were not treated. The primary outcome measure was absolute cerebral blood flow (CBF) in the hypoperfused region at 72 h.

RESULTS

The mean baseline absolute CBF in the hypoperfused region was similar in the NTG group (33.3 ± 10.2 ml/100 g/min) and untreated (32.7 ± 8.4 ml/100 g/min, p = 0.4) groups. The median (IQR) baseline infarct volume was 10.4 (2.5-49.3) ml in the NTG group and 32.6 (8.6-96.7) ml in the untreated group (p = 0.09). MAP change in the NTG group was 1.2 ± 12.6 and 8 ± 20.7 mmHg at 2 h and 72 h, respectively. Mean absolute CBF in the hypoperfused region at 72 h was similar in the NTG (29.9 ± 12 ml/100 g/min) and untreated groups (24.1 ± 10 ml/100 g/min, p = 0.8). The median infarct volume increased in untreated (11.8 (5.7-44.2) ml) than the NTG group (3.2 (0.5-16.5) ml; p = 0.033) on univariate analysis, however, there was no difference on regression analysis.

CONCLUSION

NTG was not associated with improvement in cerebral perfusion in acute ischemic stroke patients.

Comparing the effect of positioning on cerebral autoregulation during radical prostatectomy: a prospective observational study

Purpose

Surgery in the prolonged extreme Trendelenburg position may lead to elevated intracranial pressure and compromise cerebral hemodynamic regulation. We hypothesized that robot-assisted radical prostatectomy with head-down tilt causes impairment of cerebral autoregulation compared with open retropubic radical prostatectomy in the supine position.

Methods

Patients scheduled for elective radical prostatectomy were included at a tertiary care prostate cancer clinic. Continuous monitoring of the cerebral autoregulation was performed using the correlation method. Based on measurements of cerebral oxygenation with near-infrared spectroscopy and invasive mean arterial blood pressure (MAP), a moving correlation coefficient was calculated to obtain the cerebral oxygenation index as an indicator of cerebral autoregulation. Cerebral autoregulation was measured continuously from induction until recovery from anesthesia.

Results

There was no significant difference in cerebral autoregulation between robot-assisted and open retropubic radical prostatectomy during induction (p = 0.089), intraoperatively (p = 0.162), and during recovery from anesthesia (p = 0.620). Age (B = 0.311 [95% CI 0.039; 0.583], p = 0.025) and a higher difference between baseline MAP and intraoperative MAP (B = 0.200 [95% CI 0.073; 0.327], p = 0.002) were associated with impaired cerebral autoregulation, whereas surgical technique was not (B = 3.339 [95% CI  1.275; 7.952], p = 0.155).

Conclusion

Compared with open radical prostatectomy in the supine position, robot-assisted surgery in the extreme Trendelenburg position with capnoperitoneum did not lead to an impairment of cerebral autoregulation during the perioperative period in our study population.

Trial registration number: DRKS00010014, date of registration: 21.03.2016, retrospectively registered.

Electronic supplementary material

The online version of this article (10.1007/s10877-020-00549-0) contains supplementary material, which is available to authorized users.

Cerebral small vessel disease: from a focal to a global perspective

Cerebral small vessel disease (SVD) is commonly observed on neuroimaging among elderly individuals and is recognized as a major vascular contributor to dementia, cognitive decline, gait impairment, mood disturbance and stroke. However, clinical symptoms are often highly inconsistent in nature and severity among patients with similar degrees of SVD on brain imaging. Here, we provide a new framework based on new advances in structural and functional neuroimaging that aims to explain the remarkable clinical variation in SVD. First, we discuss the heterogeneous pathology present in SVD lesions despite an identical appearance on imaging and the perilesional and remote effects of these lesions. We review effects of SVD on structural and functional connectivity in the brain, and we discuss how network disruption by SVD can lead to clinical deficits. We address reserve and compensatory mechanisms in SVD and discuss the part played by other age-related pathologies. Finally, we conclude that SVD should be considered a global rather than a focal disease, as the classically recognized focal lesions affect remote brain structures and structural and functional network connections. The large variability in clinical symptoms among patients with SVD can probably be understood by taking into account the heterogeneity of SVD lesions, the effects of SVD beyond the focal lesions, the contribution of neurodegenerative pathologies other than SVD, and the interaction with reserve mechanisms and compensatory mechanisms.

Effects of Nilvadipine on Cerebral Blood Flow in Patients With Alzheimer Disease

Cerebrovascular changes, including reduced cerebral blood flow (CBF), occur early in the development of Alzheimer disease and may accelerate disease progression. This randomized, double-blind, placebo-controlled study investigated how 6 months of treatment with the calcium antagonist nilvadipine would affect CBF in patients with mild-to-moderate Alzheimer disease. CBF was measured with magnetic resonance arterial spin labeling in whole-brain gray matter and in a priori defined regions of interest including the hippocampus. Fifty-eight patients were randomly assigned (29 in each group), of whom 22 in both groups had no magnetic resonance exclusion criteria and were medication compliant over 6 months. Mean age was 72.8±6.2 years, mean mini-mental state examination was 20.4±3.4. Nilvadipine treatment lowered systolic blood pressure (Δ=-11.5 [95% CI, -19.7 to -3.2] mm Hg; P<0.01), while whole-brain gray-matter CBF remained stable (Δ=5.4 [95% CI, -6.4 to 17.2] mL/100 g per minute; P=0.36). CBF in the hippocampus increased (left: Δ=24.4 [95% CI, 4.3-44.5] mL/100 g per minute; P=0.02; right: Δ=20.1 [95% CI, -0.6 to 40.8] mL/100 g per minute; P=0.06). There was no significant change in CBF in the posterior cingulate cortex (Δ=5.2 [95% CI, -16.5 to 27.0] mL/100 g per minute; P=0.63) or other regions of interest. In conclusion, nilvadipine reduced blood pressure and increased CBF in the hippocampus, whereas other regions showed stable or small nonsignificant increases in CBF. These findings not only indicate preserved cerebral autoregulation in Alzheimer disease but also point toward beneficial cerebrovascular effects of antihypertensive treatment. Clinical Trial Registration- URL: http://www.clinicaltrials.gov . Unique identifier: NCT02017340.

Effect of Standard vs Intensive Blood Pressure Control on Cerebral Blood Flow in Small Vessel Disease: The PRESERVE Randomized Clinical Trial

Importance

Blood pressure (BP) lowering is considered neuroprotective in patients with cerebral small vessel disease; however, more intensive regimens may increase cerebral hypoperfusion. This study examined the effect of standard vs intensive BP treatment on cerebral perfusion in patients with severe small vessel disease.

Objective

To investigate whether standard vs intensive BP lowering over 3 months causes decreased cerebral perfusion in small vessel disease.

Design, Setting, and Participants

This randomized clinical trial took place at 2 English university medical centers. Patients were randomized via a central online system (in a 1:1 ratio). Seventy patients with hypertension and with magnetic resonance imaging-confirmed symptomatic lacunar infarct and confluent white matter hyperintensities were recruited between February 29, 2012, and October 21, 2015, and randomized (36 in the standard group and 34 in the intensive group). Analyzable data were available in 62 patients, 33 in the standard group and 29 in the intensive group, for intent-to-treat analysis. This experiment examines the 3-month follow-up period.

Interventions

Patients were randomized to standard (systolic, 130-140 mm Hg) or intensive (systolic, <125 mm Hg) BP targets, to be achieved through medication changes.

Main Outcomes and Measures

Cerebral perfusion was measured using arterial spin labeling; the primary end point was change in global perfusion between baseline and 3 months, compared between treatment groups by analysis of variance. Linear regression compared change in perfusion against change in BP. Magnetic resonance imaging scan analysis was masked to treatment group.

Results

Among 62 analyzable patients, the mean age was 69.3 years, and 60% (n = 37) were male. The mean (SD) systolic BP decreased by 8 (12) mm Hg in the standard group and by 27 (17) mm Hg in the intensive group (P < .001), with mean (SD) achieved pressures of 141 (13) and 126 (10) mm Hg, respectively. Change in global perfusion did not differ between treatment groups: the mean (SD) change was -0.5 (9.4) mL/min/100 g in the standard group vs 0.7 (8.6) mL/min/100 g in the intensive group (partial η2, 0.004; 95% CI, -3.551 to 5.818; P = .63). No differences were observed when the analysis examined gray or white matter only or was confined to those achieving target BP. The number of adverse events did not differ between treatment groups, with a mean (SD) of 0.21 (0.65) for the standard group and 0.32 (0.75) for the intensive group (P = .44).

Conclusions and Relevance

Intensive BP lowering did not reduce cerebral perfusion in severe small vessel disease.

Trial Registration

isrctn.org Identifier: ISRCTN37694103.

Effect of Intensive Blood-Pressure Treatment on Patient-Reported Outcomes

BACKGROUND

The previously published results of the Systolic Blood Pressure Intervention Trial showed that among participants with hypertension and an increased cardiovascular risk, but without diabetes, the rates of cardiovascular events were lower among those who were assigned to a target systolic blood pressure of less than 120 mm Hg (intensive treatment) than among those who were assigned to a target of less than 140 mm Hg (standard treatment). Whether such intensive treatment affected patient-reported outcomes was uncertain; those results from the trial are reported here.

METHODS

We randomly assigned 9361 participants with hypertension to a systolic blood-pressure target of less than 120 mm Hg or a target of less than 140 mm Hg. Patient-reported outcome measures included the scores on the Physical Component Summary (PCS) and Mental Component Summary (MCS) of the Veterans RAND 12-Item Health Survey, the Patient Health Questionnaire 9-item depression scale (PHQ-9), patient-reported satisfaction with their blood-pressure care and blood-pressure medications, and adherence to blood-pressure medications. We compared the scores in the intensive-treatment group with those in the standard-treatment group among all participants and among participants stratified according to physical and cognitive function.

RESULTS

Participants who received intensive treatment received an average of one additional antihypertensive medication, and the systolic blood pressure was 14.8 mm Hg (95% confidence interval, 14.3 to 15.4) lower in the group that received intensive treatment than in the group that received standard treatment. Mean PCS, MCS, and PHQ-9 scores were relatively stable over a median of 3 years of follow-up, with no significant differences between the two treatment groups. No significant differences between the treatment groups were noted when participants were stratified according to baseline measures of physical or cognitive function. Satisfaction with blood-pressure care was high in both treatment groups, and we found no significant difference in adherence to blood-pressure medications.

CONCLUSIONS

Patient-reported outcomes among participants who received intensive treatment, which targeted a systolic blood pressure of less than 120 mm Hg, were similar to those among participants who received standard treatment, including among participants with decreased physical or cognitive function. (Funded by the National Institutes of Health; SPRINT ClinicalTrials.gov number, NCT01206062 .).

Angiotensin II, hypertension and angiotensin II receptor antagonism: Roles in the behavioural and brain pathology of a mouse model of Alzheimer's disease

Elevated angiotensin II causes hypertension and contributes to Alzheimer's disease by affecting cerebral blood flow. Angiotensin II receptor blockers may provide candidates to reduce (vascular) risk factors for Alzheimer's disease. We studied effects of two months of angiotensin II-induced hypertension on systolic blood pressure, and treatment with the angiotensin II receptor blockers, eprosartan mesylate, after one month of induced hypertension in wild-type C57bl/6j and AβPPswe/PS1ΔE9 (AβPP/PS1/Alzheimer's disease) mice. AβPP/PS1 showed higher systolic blood pressure than wild-type. Subsequent eprosartan mesylate treatment restored this elevated systolic blood pressure in all mice. Functional connectivity was decreased in angiotensin II-infused Alzheimer's disease and wild-type mice, and only 12 months of Alzheimer's disease mice showed impaired cerebral blood flow. Only angiotensin II-infused Alzheimer's disease mice exhibited decreased spatial learning in the Morris water maze. Altogether, angiotensin II-induced hypertension not only exacerbated Alzheimer's disease-like pathological changes such as impairment of cerebral blood flow, functional connectivity, and cognition only in Alzheimer's disease model mice, but it also induced decreased functional connectivity in wild-type mice. However, we could not detect hypertension-induced overexpression of Aβ nor increased neuroinflammation. Our findings suggest a link between midlife hypertension, decreased cerebral hemodynamics and connectivity in an Alzheimer's disease mouse model. Eprosartan mesylate treatment restored and beneficially affected cerebral blood flow and connectivity. This model could be used to investigate prevention/treatment strategies in early Alzheimer's disease.

Intensive versus Guideline Blood Pressure and Lipid Lowering in Patients with Previous Stroke: Main Results from the Pilot 'Prevention of Decline in Cognition after Stroke Trial' (PODCAST) Randomised Controlled Trial

BACKGROUND

Stroke is associated with the development of cognitive impairment and dementia. We assessed the effect of intensive blood pressure (BP) and/or lipid lowering on cognitive outcomes in patients with recent stroke in a pilot trial.

METHODS

In a multicentre, partial-factorial trial, patients with recent stroke, absence of dementia, and systolic BP (SBP) 125-170 mmHg were assigned randomly to at least 6 months of intensive (target SBP <125 mmHg) or guideline (target SBP <140 mmHg) BP lowering. The subset of patients with ischaemic stroke and total cholesterol 3.0-8.0 mmol/l were also assigned randomly to intensive (target LDL-cholesterol <1.3 mmol/l) or guideline (target LDL-c <3.0 mmol/l) lipid lowering. The primary outcome was the Addenbrooke's Cognitive Examination-Revised (ACE-R).

RESULTS

We enrolled 83 patients, mean age 74.0 (6.8) years, and median 4.5 months after stroke. The median follow-up was 24 months (range 1-48). Mean BP was significantly reduced with intensive compared to guideline treatment (difference -10·6/-5·5 mmHg; p<0·01), as was total/LDL-cholesterol with intensive lipid lowering compared to guideline (difference -0·54/-0·44 mmol/l; p<0·01). The ACE-R score during treatment did not differ for either treatment comparison; mean difference for BP lowering -3.6 (95% CI -9.7 to 2.4), and lipid lowering 4.4 (95% CI -2.1 to 10.9). However, intensive lipid lowering therapy was significantly associated with improved scores for ACE-R at 6 months, trail making A, modified Rankin Scale and Euro-Qol Visual Analogue Scale. There was no difference in rates of dementia or serious adverse events for either comparison.

CONCLUSION

In patients with recent stroke and normal cognition, intensive BP and lipid lowering were feasible and safe, but did not alter cognition over two years. The association between intensive lipid lowering and improved scores for some secondary outcomes suggests further trials are warranted.

TRIAL REGISTRATION

ISRCTN ISRCTN85562386.

Influence of sleep duration on cortical oxygenation in elderly individuals

AIM

Short sleep duration is a risk factor for cardiovascular diseases. Cerebral blood flow and its regulation are affected by pathological conditions commonly observed in the elderly population, such as dementia, atherosclerosis, diabetes mellitus (DM), stroke, and hypertension. The purpose of this study was to examine the influence of sleep duration on cortical oxygenated hemoglobin (OxyHb) using near-infrared spectroscopy (NIRS).

METHODS

Seventy-three individuals (age, 70.1 ± 3.9 years, 51 men and 22 women) participated in this study. Cortical OxyHb levels were measured with NIRS. We evaluated age, body mass index (BMI), smoking status, alcohol intake, sleep duration, hypertension, DM, and hyperlipidemia using a questionnaire. Blood pressure was measured using plethysmography.

RESULTS

Peak OxyHb and area under the NIRS curve significantly decreased in participants with sleep duration <7 h compared with those with sleep duration ≥7 h (0.136 ± 0.212 mM·mm vs 0.378 ± 0.342 mM·mm, P = 0.001; 112.0 ± 243.6 vs 331.7 ± 428.7, P  = 0.012, respectively). Sleep duration was significantly correlated with peak OxyHb level and area under the NIRS curve (r = 0.378, P  = 0.001; r = 0.285, P  = 0.015, respectively). Multiple regression analysis, including age, BMI, sex, smoking status, alcohol intake, sleep duration, hypertension, DM, and hyperlipidemia revealed that sleep duration was the only significant independent factor associated with peak OxyHb and area under the NIRS curve (β = 0.343, P  = 0.004; β = 0.244, P  = 0.049, respectively), and smoking status was independently correlated with time to the peak OxyHb (β = -0.319, P  = 0.009).

CONCLUSION

Sleep duration may be an important factor that influences cortical oxygenation in the elderly population.

Hemodynamic correlates of transient cognitive impairment after transient ischemic attack and minor stroke: A transcranial Doppler study

Background and aims

Transient cognitive impairment (TCI) on the Mini Mental State Evaluation score is common after transient ischemic attack/minor stroke and might identify patients at increased risk of dementia. We aimed to replicate TCI using the Montreal Cognitive Assessment (MoCA), compare it with persistent Mild Cognitive Impairment (PMCI), and to determine whether global cerebral hemodynamic changes could explain transient impairment.

Methods

Consecutive patients with transient ischemic attack/minor stroke (NIHSS ≤ 3) were assessed with the MoCA and transcranial Doppler ultrasound acutely and at 1 month. We compared patients with TCI (baseline MoCA < 26 with ≥ 2 points increase at 1 month), PMCI (MoCA < 26 with < 2 points increase), and no cognitive impairment (NCI; MoCA ≥ 26).

Results

Of 326 patients, 46 (14.1%) had PMCI, 98 (30.1%) TCI, and 182 (55.8%) NCI. At baseline, TCI patients had higher systolic blood pressure (150.95 ± 21.52 vs 144.86 ± 22.44 mmHg, p = 0.02) and lower cerebral blood flow velocities, particularly end-diastolic velocity (30.16 ± 9.63 vs 35.02 ± 9.01 cm/s, p < 0.001) and mean flow velocity (48.95 ± 12.72 vs 54 ± 12.46 cm/s, p = 0.001) than those with NCI, but similar clinical and hemodynamic profiles to those with PMCI. Systolic BP fell between baseline and 1 month (mean reduction = 14.01 ± 21.26 mmHg) and end-diastolic velocity and mean flow velocity increased (mean increase = + 2.42 ± 6.41 and 1.89 ± 8.77 cm/s, respectively), but these changes did not differ between patients with TCI, PMCI, and NCI.

Conclusions

TCI is detectable with the MoCA after transient ischemic attack and minor stroke and has similar clinical and hemodynamic profile to PMCI. However, TCI does not appear to be due to exaggerated acute reversible global hemodynamic changes.

White Matter Hyperintensity Volume and Cerebral Perfusion in Older Individuals with Hypertension Using Arterial Spin-Labeling

BACKGROUND AND PURPOSE

White matter hyperintensities of presumed vascular origin in elderly patients with hypertension may be part of a general cerebral perfusion deficit, involving not only the white matter hyperintensities but also the surrounding normal-appearing white matter and gray matter. We aimed to study the relation between white matter hyperintensity volume and CBF and assess whether white matter hyperintensities are related to a general perfusion deficit.

MATERIALS AND METHODS

In 185 participants of the Prevention of Dementia by Intensive Vascular Care trial between 72 and 80 years of age with systolic hypertension, white matter hyperintensity volume and CBF were derived from 3D FLAIR and arterial spin-labeling MR imaging, respectively. We compared white matter hyperintensity CBF, normal-appearing white matter CBF, and GM CBF across quartiles of white matter hyperintensity volume and assessed the continuous relation between these CBF estimates and white matter hyperintensity volume by using linear regression.

RESULTS

Mean white matter hyperintensity CBF was markedly lower in higher quartiles of white matter hyperintensity volume, and white matter hyperintensity volume and white matter hyperintensity CBF were negatively related (standardized β = -0.248, P = .001) in linear regression. We found no difference in normal-appearing white matter or GM CBF across quartiles of white matter hyperintensity volume or any relation between white matter hyperintensity volume and normal-appearing white matter CBF (standardized β = -0.065, P = .643) or GM CBF (standardized β = -0.035, P = .382) in linear regression.

CONCLUSIONS

Higher white matter hyperintensity volume in elderly individuals with hypertension was associated with lower perfusion within white matter hyperintensities, but not with lower perfusion in the surrounding normal-appearing white matter or GM. These findings suggest that white matter hyperintensities in elderly individuals with hypertension relate to local microvascular alterations rather than a general cerebral perfusion deficit.