Visit-to-visit office blood pressure variability combined with Framingham risk score to predict all-cause mortality: A post hoc analysis of the systolic blood pressure intervention trial

Impact of seasonal blood pressure changes on visit-to-visit blood pressure variability and related cardiovascular outcomes

BACKGROUND

Visit-to-visit blood pressure (BP) variability associates with an increased risk of cardiovascular events. We investigated the role of seasonal BP modifications on the magnitude of BP variability and its impact on cardiovascular risk.

METHODS

In 25 390 patients included in the ONTARGET and TRANSCEND trials, the on-treatment systolic (S) BP values obtained by five visits during the first two years of the trials were grouped according to the month in which they were obtained. SBP differences between winter and summer months were calculated for BP variability quintiles (Qs), as quantified by the coefficient of variation (CV) of on-treatment mean SBP from the five visits. The relationship of BP variability with the risk of cardiovascular events and mortality was assessed by the Cox regression model.

RESULTS

SBP was approximately 4 mmHg lower in summer than in winter regardless of confounders. Winter/summer SBP differences contributed significantly to each SBP-CV quintile. Increase of SBP-CV from Q1 to Q5 was associated with a progressive increase in the adjusted hazard ratio (HR) of the primary endpoint of the trials, i.e. morbid and fatal cardiovascular events. This association was even stronger after removal of the effect of seasonality from the calculation of SBP-CV. A similar trend was observed for secondary endpoints.

CONCLUSIONS

Winter/summer SBP differences significantly contribute to visit-to-visit BP variability. However, this contribution does not participate in the adverse prognostic significance of visit-to-visit BP variations, which seems to be more evident after removal of the BP effects of seasonality from visit-to-visit BP variations.

Abnormal blood pressure dipping pattern: frequency, determinants, and correlates in Diabetes Mellitus patients in the Cardiovascular Health Risk Assessment in Diabetes Mellitus (CHiD) study

Purpose

Non-dipping status is associated with increased total and cardiovascular mortality in many disease conditions including diabetes mellitus. The pattern and its implications are not well described among Africans. This study was done to describe the frequency of abnormal blood pressure (BP) dipping among T2DM subjects, its determinants and correlates in Ogbomoso, Nigeria.

Methods

This was a cross-sectional study done at the LAUTECH Teaching Hospital, Ogbomoso. One hundred individuals diagnosed with T2DM were recruited and they had 24-hour ambulatory BP monitoring, echocardiography, ECG, and carotid Doppler among other evaluations. Statistical analysis was done using SPSS 27.0 (Chicago Ill, USA).

Results

The mean age of the participants was 59.3 ± 10.8 years, mean body mass index 27.7 ± 5.9 kg/m2 with a mean duration of diabetes of 7.52 ± 5.54 years. Abnormal BP dipping was present in 89% (consisting of 41% or reverse dippers and 48% non-dippers). T2DM subjects with abnormal dipping pattern were more likely to be females, had higher glycated haemoglobin, lower fractional shortening, higher left atrial volume and left ventricular mass index, and a higher DM duration than those with normal BP dipping status. The major determinants of abnormal dipping pattern were the duration of diabetes and low HDL-C concentration.

Conclusion

Abnormal BP dipping pattern is highly prevalent in T2DM subjects, especially among females. Abnormal BP dipping was also associated with markers of increased cardiovascular risk such as impaired kidney function, left ventricular hypertrophy, postural hypotension, history of intermittent claudication, and presence of plaques on carotid Doppler studies.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-023-01337-8.

Long-term systolic blood pressure variability independent of mean blood pressure is associated with mortality and cardiovascular events: A systematic review and meta-analysis

The association between long-term systolic blood pressure variability (SBPV) and cardiovascular (CV) outcomes after being adjusted with mean blood pressure (BP) is questionable. This systematic review aims to evaluate the associations between mean BP adjusted long-term SBPV and CV outcomes. A systematic search was conducted on PubMed, Scopus, and Science Direct on January 4, 2023. A total of 9,944,254 subjects from 43 studies were included in this meta-analysis. Long-term SBPV increased the risk of all-cause mortality (HR 1.21 [95%CI 1.16-1.25], I2=100%), CV mortality (HR 1.10 [95%CI 1.07-11.4], I2 = 90%), MACE (HR 1.10 [1.07-1.13], I2 = 91%), cerebrovascular stroke (HR 1.22 [1.16-1.29], I2=100%), and myocardial infarction (HR 1.13 [95%CI (1.07-1.19)], I2=91%). European populations generally had higher risk compared to other continents. In conclusion, long-term SBPV is associated with all-cause mortality, CV mortality, MACE, MI, and stroke. Poor outcomes related to long-term SBPV seem more dominated by cerebrovascular than coronary events.

Blood Pressure Variability and Plasma Alzheimer's Disease Biomarkers in the SPRINT Trial

Background

Recent observational studies suggest higher blood pressure (BP) variability (BPV) is associated with Alzheimer's disease (AD) biomarkers amyloid-beta (Aβ) and tau. Less is known about relationships in interventional cohorts with strictly controlled mean BP levels.

Objective

Investigate the longitudinal relationship between BPV and change in plasma AD biomarkers under standard versus intensive BP treatment.

Methods

In this post hoc analysis of the SPRINT trial, 457 participants (n = 206 in standard group, n = 251 in intensive group) underwent repeated BP measurement between baseline and 12-months follow-up, and venipuncture at baseline and median (IQR) 3.5 (3.0-4.0) years later to determine plasma AD biomarkers total tau and Aβ1-42:Aβ1-40 ratio. BPV was calculated as tertiles of variability independent of mean. Linear mixed models investigated the effect of BPV×time on AD biomarker levels.

Results

Higher BPV was associated with increased levels of total tau in the standard group (β [95% CI] 1st versus 3rd tertiles of BPV: 0.21 [0.02, 0.41], p = 0.035), but not in the intensive group (β [95% CI] 1st versus 3rd tertiles of BPV: -0.02 [-0.19, 0.16], p = 0.843). BPV was not associated with Aβ 1-42:Aβ 1-40 ratio in either group. Mean BP was not associated with biomarkers.

Conclusions

Higher BPV was associated with increased plasma total tau under standard BP treatment. Findings add new evidence to prior observational work linking BPV to AD pathophysiology and suggest that, despite strict control of mean BP, BPV remains a risk for pathophysiological change underlying risk for AD.

24-Hour Blood Pressure Variability Via Ambulatory Monitoring and Risk for Probable Dementia in the SPRINT Trial

BACKGROUND

Blood pressure variability is an emerging risk factor for dementia, independent and oftentimes beyond mean blood pressure levels. Recent evidence from interventional cohorts with rigorously controlled mean blood pressure levels suggest blood pressure variability over months to years remains a risk for dementia, but no prior studies have investigated relationships with blood pressure variability over shorter time periods.

OBJECTIVES

To investigate the potential effect of ambulatory blood pressure variability on the rate of cognitive outcomes under intensive vs standard blood pressure lowering.

DESIGN

Post hoc analysis of the randomized, controlled, open-label Systolic Blood Pressure Intervention Trial clinical trial.

SETTING

Multisite Systolic Blood Pressure Intervention Trial.

PARTICIPANTS

793 participants at increased risk for cardiovascular disease and without history of dementia at study randomization.

INTERVENTION

Standard (<140 mmHg systolic blood pressure target) vs intensive (<120 mmHg systolic blood pressure target) lowering of mean blood pressure.

MEASUREMENTS

24-hour ambulatory blood pressure monitoring 27 months after treatment randomization (standard vs intensive) and follow-up cognitive testing. Intraindividual blood pressure variability was calculated as the average real variability over 24-hour, daytime, and nighttime periods. Participants were categorized into 3 adjudicated clinical outcomes: no cognitive impairment, mild cognitive impairment, probable dementia. Cox proportional hazards models examined the potential effect of ambulatory blood pressure variability on the rate of cognitive outcomes under intensive vs standard blood pressure lowering. Associations with mean blood pressure were also explored.

RESULTS

Higher systolic 24-hour blood pressure variability was associated with increased risk for probable dementia in the standard group (adjusted hazard ratio [HR]: 2.56 [95% CI 1.16, 5.62], p = 0.019) but not in the intensive group (HR: 0.54 [95% CI 0.24, 1.23], p = 0.141). Similar findings were observed with daytime systolic blood pressure variability but not nighttime blood pressure variability. Mean blood pressure was not associated with cognitive outcomes.

CONCLUSIONS

Higher systolic 24-hour and daytime blood pressure variability via ambulatory monitoring is associated with risk for dementia under standard blood pressure treatment. Findings support prior evidence that blood pressure variability remains a risk for dementia despite strict control of mean blood pressure levels.

Blood Pressure Variability and Cerebral Perfusion Decline: A Post Hoc Analysis of the SPRINT MIND Trial

Background Blood pressure variability (BPV) is predictive of cerebrovascular disease and dementia, possibly though cerebral hypoperfusion. Higher BPV is associated with cerebral blood flow (CBF) decline in observational cohorts, but relationships in samples with strictly controlled blood pressure remain understudied. We investigated whether BPV relates to change in CBF in the context of intensive versus standard antihypertensive treatment. Methods and Results In this post hoc analysis of the SPRINT MIND (Systolic Blood Pressure Intervention Trial-Memory and Cognition in Decreased Hypertension) trial, 289 participants (mean, 67.6 [7.6 SD] years, 38.8% women) underwent 4 blood pressure measurements over a 9-month period after treatment randomization (intensive versus standard) and pseudo-continuous arterial spin labeling magnetic resonance imaging at baseline and ≈4-year follow-up. BPV was calculated as tertiles of variability independent of mean. CBF was determined for whole brain, gray matter, white matter, hippocampus, parahippocampal gyrus, and entorhinal cortex. Linear mixed models examined relationships between BPV and change in CBF under intensive versus standard antihypertensive treatment. Higher BPV in the standard treatment group was associated with CBF decline in all regions (ß comparing the first versus third tertiles of BPV in whole brain: -0.09 [95% CI, -0.17 to -0.01]; P=0.03), especially in medial temporal regions. In the intensive treatment group, elevated BPV was related to CBF decline only in the hippocampus (ß, -0.10 [95% CI, -0.18, -0.01]; P=0.03). Conclusions Elevated BPV is associated with CBF decline, especially under standard blood pressure-lowering strategies. Relationships were particularly robust in medial temporal regions, consistent with prior work using observational cohorts. Findings highlight the possibility that BPV remains a risk for CBF decline even in individuals with strictly controlled mean blood pressure levels. Registration URL: http://clinicaltrials.gov. Identifier: NCT01206062.

Blood pressure variability: methodological aspects, clinical relevance and practical indications for management - a European Society of Hypertension position paper ∗

Blood pressure is not a static parameter, but rather undergoes continuous fluctuations over time, as a result of the interaction between environmental and behavioural factors on one side and intrinsic cardiovascular regulatory mechanisms on the other side. Increased blood pressure variability (BPV) may indicate an impaired cardiovascular regulation and may represent a cardiovascular risk factor itself, having been associated with increased all-cause and cardiovascular mortality, stroke, coronary artery disease, heart failure, end-stage renal disease, and dementia incidence. Nonetheless, BPV was considered only a research issue in previous hypertension management guidelines, because the available evidence on its clinical relevance presents several gaps and is based on heterogeneous studies with limited standardization of methods for BPV assessment. The aim of this position paper, with contributions from members of the European Society of Hypertension Working Group on Blood Pressure Monitoring and Cardiovascular Variability and from a number of international experts, is to summarize the available evidence in the field of BPV assessment methodology and clinical applications and to provide practical indications on how to measure and interpret BPV in research and clinical settings based on currently available data. Pending issues and clinical and methodological recommendations supported by available evidence are also reported. The information provided by this paper should contribute to a better standardization of future studies on BPV, but should also provide clinicians with some indications on how BPV can be managed based on currently available data.

Blood Pressure Variability and Cognitive Decline: A Post Hoc Analysis of the SPRINT MIND Trial

BACKGROUND

Blood pressure (BP) variability (BPV) is an emerging risk factor for cognitive impairment and dementia, but relationships with cognition in the context of antihypertensive strategies remain unclear. We examined whether visit-to-visit BPV relates to cognitive change based on antihypertensive treatment type.

METHODS

In this post hoc analysis of the SPRINT MIND trial, 2,348 participants underwent 4 BP measurements over a 9-month period after treatment randomization (standard vs. intensive BP lowering) and ≥ 1 neuropsychological evaluation thereafter. BPV was calculated as tertiles of BP SD. Participants underwent cognitive testing at baseline and every 2 years during the planned 4-year follow-up. Cognitive composite scores were calculated for global cognition, memory, language, executive function, and processing speed. Linear mixed models investigated relationships between BPV, antihypertensive treatment group, and time on cognitive composite scores.

RESULTS

Elevated BPV was associated with the fastest decline in processing speed (ß = -.07 [95% CI -.12, -.01]; P = 0.02) and executive function (ß = -.08 [95% CI -.16, -.006]; P = 0.03) in the standard treatment group only. BPV was not related to cognitive change in the intensive treatment group. Mean/minimum/maximum BP was not associated with cognitive composite scores over time in either antihypertensive treatment group.

CONCLUSIONS

Elevated BPV remains a risk for cognitive decline despite strictly controlled BP levels, in the standard treatment group. Specific declines were observed in processing speed and executive function, domains often impacted by cerebrovascular disease and may underpin risk for dementia and cerebrovascular disease associated with BPV. Clinical trial information: ClinicalTrials.gov; NCT01206062.

Effect of visit-to-visit blood pressure variability on mild cognitive impairment and probable dementia in hypertensive patients receiving standard and intensive blood pressure treatment

Background

High visit-to-visit blood pressure variability (BPV) and hypertension are risk factors for mild cognitive impairment (MCI) and probable dementia (PD). Few articles assessed the effect of BPV on the MCI and PD in intensive blood pressure treatment and the different functions of three types of visit-to-visit BPV: systolic blood pressure variability (SBPV), diastolic blood pressure variability (DBPV) and pulse pressure variability (PPV).

Methods

We performed a post hoc analysis of the SPRINT MIND trial. The primary outcomes were MCI and PD. BPV was measured by average real variability (ARV). The Kaplan-Meier curves were used to clarify the difference in tertiles of BPV. We fit Cox proportional hazards models to our outcome. We also did an interaction analysis between the intensive and standard groups.

Results

We enrolled 8,346 patients in the SPRINT MIND trial. The incidence of MCI and PD in the intensive group was lower than that in the standard group. 353 patients had MCI and 101 patients had PD in the standard group while 285 patients had MCI and 75 patients had PD in the intensive group. Tertiles with higher SBPV, DBPV and PPV in the standard group had a higher risk of MCI and PD (all p < 0.05). Meanwhile, higher SBPV and PPV in the intensive group were associated with an increased risk of PD (SBPV: HR(95%) = 2.1 (1.1-3.9), p = 0.026; PPV: HR(95%) = 2.0 (1.1-3.8), p = 0.025 in model 3) and higher SBPV in the intensive group was associated with an increased risk of MCI(HR(95%) = 1.4 (1.2-1.8), p < 0.001 in model 3). The difference between intensive and standard blood pressure treatment was not statistically significant when we considered the effect of the higher BPV on the risk of MCI and PD (all p for interaction >0.05).

Conclusion

In this post hoc analysis of the SPRINT MIND trial, we found that higher SBPV and PPV were associated with an increased risk of PD in the intensive group, and higher SBPV was associated with an increased risk of MCI in the intensive group. The effect of higher BPV on the risk of MCI and PD was not significantly different in intensive and standard blood pressure treatment. These findings emphasized the need for clinical work to monitor BPV in intensive blood pressure treatment.

Visit-To-Visit Blood Pressure Variability and Subthreshold Depressive Symptoms in Older Adults

OBJECTIVES

Depression is related to increased risk for dementia, possibly through links with cerebrovascular disease. Blood pressure variability is an emerging risk factor for cerebrovascular disease and dementia, but relationships with affective symptoms remain understudied.

DESIGN

Retrospective analysis of prospective cohort study.

SETTING

Alzheimer's Disease Neuroimaging Initiative.

PARTICIPANTS

505 older adults without history of dementia or recent depression underwent three to four blood pressure measurements over 12 months and completed a self-report measure of depressive symptoms (Geriatric Depression Scale - 15 Item) at study baseline and 24-months follow-up.

MEASUREMENTS

Blood pressure variability was calculated as variability independent of mean and maximum minus minimum. Regression models investigated relationships between blood pressure variability and severity of self-reported depressive symptoms at 24-months follow-up after controlling for several variables, including average blood pressure, antihypertensive use, antidepressant use, and baseline depressive symptom severity.

RESULTS

Elevated diastolic blood pressure variability was related to greater total depressive symptom score at follow-up (ß = .16 [95% CI 0.02, .30]; p = 0.03), with specific contribution from increased severity of symptoms of dysphoria (odds ratio = 1.35 [95% CI 1.07, 1.75]; p = 0.02). Blood pressure variability was not significantly related to other symptom subscales, including those reflecting life satisfaction or withdrawal.

CONCLUSIONS

Findings suggest that elevated diastolic blood pressure variability is related to subthreshold depressive symptomatology in older adults without history of dementia or recent depression, independent of average blood pressure. Blood pressure variability may be an understudied vascular risk factor linked with depression and cognitive impairment, with potential therapeutic implications.

Long-term variability and change trend of systolic blood pressure and risk of type 2 diabetes mellitus in middle-aged Japanese individuals: findings of the Aichi Workers' Cohort Study

Studies have reported that short-term blood pressure (BP) variability (BPV) is associated with type 2 diabetes mellitus (T2DM) incidence, but the association with long-term BPV remains unclear. The present study investigated the associations of long-term BPV as well as the time trend of BP changes over time with the incidence of T2DM. This study followed a cohort of 3017 Japanese individuals (2446 male, 571 female) aged 36-65 years from 2007 through March 31, 2019. The root-mean-square error (RMSE) and the slope of systolic BP (SBP) change regressed on year were calculated individually using SBP values obtained from 2003 to baseline (2007). A multivariable Cox proportional hazard model was applied to estimate hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) for tertiles of SBP RMSE and continuous SBP slopes adjusted for age, sex, smoking status, regular exercise, sodium intake, family history of diabetes, sleep disorder, body mass index (BMI), SBP, and fasting blood glucose (FBG) at baseline, and BMI slope from 2003 to 2007. The highest RMSE tertile compared to the lowest was associated with a significantly higher incidence of T2DM after adjusting for covariates (HR: 1.79, 95% CI: 1.15, 2.78). The slope was also significantly associated with T2DM incidence until baseline SBP and FBG were adjusted (HR: 1.03, 95% CI: 0.99, 1.07). In conclusion, long-term SBP variability was significantly associated with an increased incidence of T2DM independent of baseline age, sex, BMI, SBP, FBG, lifestyle factors and BMI slope from 2003 until baseline.

Visit-to-Visit Blood Pressure Variability and CSF Alzheimer Disease Biomarkers in Cognitively Unimpaired and Mildly Impaired Older Adults

BACKGROUND AND OBJECTIVES

Blood pressure variability is an emerging risk factor for cognitive decline and dementia, but mechanisms remain unclear. The current study examined whether visit-to-visit blood pressure variability is related to CSF Alzheimer disease biomarker levels over time and whether associations differed by APOE ε4 carrier status.

METHODS

In this retrospective analysis of a prospective cohort study, cognitively unimpaired or mildly impaired older adults from the Alzheimer's Disease Neuroimaging Initiative underwent 3 to 4 blood pressure measurements over a 12-month period and ≥1 lumbar puncture for evaluation of CSF phosphorylated tau, total tau, and β-amyloid levels at follow-up (6-108 months later). APOE ε4 carriers were defined as having ≥1 ε4 allele. Visit-to-visit blood pressure variability was determined over 12 months as variability independent of mean. Only CSF samples collected after the final blood pressure measurement were analyzed. Bayesian linear growth modeling investigated the role of blood pressure variability, APOE ε4, and the passage of time on CSF biomarker levels after controlling for several variables, including average blood pressure and baseline hypertension.

RESULTS

Four hundred sixty-six participants (mean 76.7 [SD 7.1] years of age) were included in the study. Elevated blood pressure variability was associated with increased CSF phosphorylated tau (β = 0.81 [95% CI 0.74, 0.97]), increased total tau (β = 0.98 [95% CI 0.71, 1.31]), and decreased β-amyloid levels (β = -1.52 [95% CI -3.55, -0.34]) at follow-up. APOE ε4 carriers with elevated blood pressure variability had the fastest increase in phosphorylated tau levels (β = 9.03 [95% CI 1.67, 16.36]). Blood pressure variability was not significantly related to total tau or β-amyloid levels over time according to APOE ε4 carrier status.

DISCUSSION

Older adults with elevated blood pressure variability exhibit increased CSF phosphorylated tau, increased total tau, and decreased β-amyloid over time, suggesting that blood pressure variability may correlate with alterations in Alzheimer disease biomarkers. Findings warrant further study of the relationship between blood pressure variability and the development of Alzheimer disease. APOE ε4 carrier status moderated relationships between blood pressure variability and CSF phosphorylated tau but not total tau or β-amyloid, consistent with other studies relating hemodynamic factors to tau changes.

Blood pressure and its variability: classic and novel measurement techniques

Current hypertension guidelines recommend using the average values of several blood pressure (BP) readings obtained both in and out of the office for the diagnosis and management of hypertension. In-office BP measurement using an upper-arm cuff constitutes the evidence-based reference method for current BP classification and treatment targets. However, out-of-office BP evaluation using 24 h ambulatory or home BP monitoring is recommended by all major medical associations for obtaining further insights into the BP profile of an individual and how it relates to their daily activities. Importantly, the highly variable nature of office and out-of-office BP readings has been widely acknowledged, including the association of BP variability with cardiovascular outcomes. However, to date, the implications of BP variability on cardiovascular outcomes have largely been ignored, with limited application in clinical practice. Novel cuffless wearable technologies might provide a detailed assessment of the 24 h BP profile and behaviour over weeks or months. These devices offer many advantages for researchers and patients compared with traditional BP monitors, but their accuracy and utility remain uncertain. In this Review, we outline and compare conventional and novel methods and techniques for assessing average BP levels and BP variability, and reflect on the utility and potential of these methods for improving the treatment and management of patients with hypertension.

The most commonly available blood pressure (BP) monitoring devices are useful for capturing a snapshot BP value, but most have limited utility in measuring BP variability. In this Review, Schutte and colleagues outline the advantages and disadvantages of conventional and novel techniques to measure average BP levels and BP variability.

Although the dynamic nature of blood pressure (BP) is well-known, hypertension guidelines recommend using the average values of static BP readings (office or out-of-office), specifically aiming to level the fluctuations and peaks in BP readings.

All current BP measurement methods have imperfect reproducibility owing to the continuous fluctuation in BP readings, making it difficult to accurately diagnose hypertension.

Accumulating evidence from clinical trials, large registries and meta-analyses shows that increased BP variability predicts cardiovascular outcome, independently of the average BP values.

To date, BP variability is overlooked, with limited application in clinical practice, probably owing to a variety of complex non-standardized BP variability assessment methods and indices, and uncertain thresholds and clinical usefulness.

Novel cuffless wearable BP technologies can provide very large numbers of readings for days and months without the discomfort of traditional BP monitoring devices, and have the potential to replace current BP methods, once accuracy issues are resolved and their clinical usefulness is proved.

Visit-to-Visit Blood Pressure Variability and Longitudinal Tau Accumulation in Older Adults

BACKGROUND

Elevated blood pressure variability (BPV) is predictive of dementia, independent of average blood pressure levels, but neuropathological mechanisms remain unclear. We examined whether BPV in older adults is related to tau accumulation in brain regions vulnerable to Alzheimer disease and whether relationships are modified by apoϵ4 carrier status.

METHODS

Two hundred eighty-six Alzheimer's Disease Neuroimaging Initiative participants without history of dementia underwent 3 to 4 blood pressure measurements over 12 months and ≥1 tau positron emission tomography thereafter. BPV was calculated as variability independent of mean. Each scan determined tau burden (standardized uptake value ratio) for a temporal meta-region of interest, including burden from entorhinal cortex, amygdala, parahippocampus, fusiform, inferior temporal, and middle temporal. Bayesian linear growth modeling examined the role of BPV, apolipoprotein ϵ4 carrier status, and time on regional tau accumulation after controlling for several variables, including baseline hypertension.

RESULTS

Elevated BPV was related to tau accumulation at follow-up in a temporal meta-region, independent of average blood pressure levels (ß, 0.89 [95% credible interval, 0.86-0.92]) and especially in entorhinal cortex (ß, 2.57 [95% credible interval, 2.15-2.99]). Apoϵ4 carriers with elevated BPV had the fastest tau accumulation at follow-up (ß, 1.73 [95% credible interval, 0.47-3.03]).

CONCLUSIONS

BPV is related to tau accumulation in brain regions vulnerable to Alzheimer disease, independent of average blood pressure. APOEϵ4 modified this relationship. Bidirectionality of findings is possible. BPV may represent a marker of vascular dysfunction related to early-stage tau pathology contributing to Alzheimer disease.

Selective vulnerability of medial temporal regions to short-term blood pressure variability and cerebral hypoperfusion in older adults

Blood pressure variability is an emerging risk factor for stroke, cognitive impairment, and dementia, possibly through links with cerebral hypoperfusion. Recent evidence suggests visit-to-visit (e.g., over months, years) blood pressure variability is related to cerebral perfusion decline in brain regions vulnerable to Alzheimer's disease. However, less is known about relationships between short-term (e.g., < 24 hours) blood pressure variability and regional cerebral perfusion, and whether these relationships may differ by age. We investigated short-term blood pressure variability and concurrent regional cerebral microvascular perfusion in a sample of community-dwelling older adults without history of dementia or stroke and healthy younger adults. Blood pressure was collected continuously during perfusion MRI. Cerebral blood flow was determined for several brain regions implicated in cerebrovascular dysfunction in Alzheimer's disease. Elevated systolic blood pressure variability was related to lower levels of concurrent cerebral perfusion in medial temporal regions: hippocampus (β = -.60 [95% CI -.90, -.30]; p < .001), parahippocampal gyrus (β = -.57 [95% CI -.89, -.25]; p = .001), entorhinal cortex (β = -.42 [95% CI -.73, -.12]; p = .009), and perirhinal cortex (β = -.37 [95% CI -.72, -.03]; p = .04), and not in other regions, and in older adults only. Findings suggest a possible age-related selective vulnerability of the medial temporal lobes to hypoperfusion in the context of short-term blood pressure fluctuations, independent of average blood pressure, white matter hyperintensities, and gray matter volume, which may underpin the increased risk for dementia associated with elevated BPV.