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

Reliability of beat-to-beat blood pressure variability in older adults

Blood pressure variability (BPV) is emerging as an important risk factor across numerous disease states, including cerebrovascular and neurodegenerative disease in older adults. However, there is no current consensus regarding specific use cases for the numerous available BPV metrics. There is also little published data supporting the ability to reliably measure BPV across metrics in older adults. The present study derived BPV metrics from continuous beat-to-beat blood pressure monitoring data. Two sequential 7 min waveforms were analyzed. Absolute and relative reliability testing was performed. Differences between antihypertensive medication users and non-users on BPV metric reliability was also assessed. All sequence and dispersion based BPV metrics displayed good test-retest reliability. A measure of BP instability displayed only moderate reliability. Systolic and diastolic average real variability displayed the highest levels of reliability at ICC = 0.87 and 0.82 respectively. Additionally, systolic average real variability was the most reliable metric in both the antihypertensive use group, and the no antihypertensive use group. In conclusion, beat-to-beat dispersion and sequence-based metrics of BPV can be reliably obtained in older adults using noninvasive continuous blood pressure monitoring. Average real variability may be the most reliable and specific beat-to-beat blood pressure variability metric due to its decreased susceptibility to outliers and low frequency blood pressure oscillations.

Assessment of blood pressure variability: characteristics and comparison of blood pressure measurement methods

Previous studies have reported that blood pressure variability (BPV) is associated with the risk of cardiovascular events independent of blood pressure (BP) levels. While there is little evidence from intervention trials examining whether suppressing BPV is useful in preventing cardiovascular disease, it is suggested that detection of abnormally elevated BPV may be useful in reducing cardiovascular events adding by complementing management of appropriate BP levels. Cuffless BP devices can assess beat-to-beat BPV. Although cuffless BP monitoring devices have measurement accuracy issues that need to be resolved, this is an area of research where the evidence is accumulating rapidly, with many publications on beat-to-beat BPV over several decades. Ambulatory BP monitoring (ABPM) can assess 24-hour BPV and nocturnal dipping patterns. Day-to-day BPV and visit-to-visit BPV are assessed by self-measured BP monitoring at home and office BP measurement, respectively. 24 h, day-to-day, and visit-to-visit BPV have been reported to be associated with cardiovascular prognosis. Although there have been several studies comparing whether ABPM and self-measured BP monitoring at home is the superior measurement method of BPV, no strong evidence has been accumulated that indicates whether ABPM or self-measured home BP is superior. ABPM and self-measured BP monitoring have their own advantages and complement each other in the assessment of BPV.

Beat-to-beat blood pressure variability, hippocampal atrophy, and memory impairment in older adults

Visit-to-visit blood pressure variability (BPV) predicts age-related hippocampal atrophy, neurodegeneration, and memory decline in older adults. Beat-to-beat BPV may represent a more reliable and efficient tool for prospective risk assessment, but it is unknown whether beat-to-beat BPV is similarly associated with hippocampal neurodegeneration, or with plasma markers of neuroaxonal/neuroglial injury. Independently living older adults without a history of dementia, stroke, or other major neurological disorders were recruited from the community (N = 104; age = 69.5 ± 6.7 (range 55-89); 63% female). Participants underwent continuous blood pressure monitoring, brain MRI, venipuncture, and cognitive testing over two visits. Hippocampal volumes, plasma neurofilament light, and glial fibrillary acidic protein levels were assessed. Beat-to-beat BPV was quantified as systolic blood pressure average real variability during 7-min of supine continuous blood pressure monitoring. The cross-sectional relationship between beat-to-beat BPV and hippocampal volumes, cognitive domain measures, and plasma biomarkers was assessed using multiple linear regression with adjustment for demographic covariates, vascular risk factors, and average systolic blood pressure. Elevated beat-to-beat BPV was associated with decreased left hippocampal volume (P = .008), increased plasma concentration of glial fibrillary acidic protein (P = .006), and decreased memory composite score (P = .02), independent of age, sex, average systolic blood pressure, total intracranial volume, and vascular risk factor burden. In summary, beat-to-beat BPV is independently associated with decreased left hippocampal volume, increased neuroglial injury, and worse memory ability. Findings are consistent with prior studies examining visit-to-visit BPV and suggest beat-to-beat BPV may be a useful marker of hemodynamic brain injury in older adults.

Relationship between changes in late-life blood pressure and the risk of frailty and mortality among older population in China: a cohort study based on CLHLS

The evidence regarding the effects of blood pressure changes on older individuals remains inconclusive, and the impact of frailty throughout the life course is not known. We investigated the associations of different change patterns of blood pressure during 3-year intervals with frailty and mortality. Participants included 7335 persons from 2008 to 2014 of the Chinese Longitudinal Healthy Longevity Survey (CLHLS). Change in blood pressure was calculated as the difference between follow-up and baseline. Frailty was evaluated using a 40-item frailty index. Mortality status was ascertained up to December 31, 2014. The mean age of participants was 82.6 ± 10.7 years. The optimal blood pressure level (SBP, 130-150 mmHg; DBP, 70-90 mmHg) was associated with the lowest risk of frailty while decreasing follow-up SBP and DBP were significantly correlated with frailty. Lower baseline blood pressure levels (SBP < 130 mmHg; DBP < 70 mmHg) were associated with decreased mortality risk when participants increased their blood pressure to optimal levels during follow-up SBP and DBP (0.78, 0.63-0.98), compared to maintaining a steady low SBP (< 130 mmHg) and DBP (< 70 mmHg). For those with DBP around 70-90 mmHg, decreasing follow-up DBP (< 70 mmHg) was associated with higher mortality (1.23, 1.07-1.42) compared to maintaining stable follow-up DBP (70-90 mmHg). These results remain significant after adjusting for frailty. Optimal blood pressure levels were associated with the lowest risk of frailty. The association between lower blood pressure and increased mortality risk persisted even after accounting for frailty. We used a nationally representative longitudinal cohort study by using 2008-2014 of the Chinese Longitudinal Healthy Longevity in China. Change in blood pressure was calculated as the difference between follow-up and baseline. We investigated the associations of different change patterns of blood pressure during 3-year intervals with frailty and mortality.

Distinct effects of blood pressure parameters on Alzheimer's and vascular markers in 1,952 Asian individuals without dementia

BACKGROUND

Risk factors for cardiovascular disease, including elevated blood pressure, are known to increase risk of Alzheimer's disease. There has been increasing awareness of the relationship between long-term blood pressure (BP) patterns and their effects on the brain. We aimed to investigate the association of repeated BP measurements with Alzheimer's and vascular disease markers.

METHODS

We recruited 1,952 participants without dementia between August 2015 and February 2022. During serial clinic visits, we assessed both systolic BP (SBP) and diastolic BP (DBP), and visit-to-visit BP variability (BPV) was quantified from repeated measurements. In order to investigate the relationship of mean SBP (or DBP) with Alzheimer's and vascular markers and cognition, we performed multiple linear and logistic regression analyses after controlling for potential confounders (Model 1). Next, we investigated the relationship of with variation of SBP (or DBP) with the aforementioned variables by adding it into Model 1 (Model 2). In addition, mediation analyses were conducted to determine mediation effects of Alzheimer's and vascular makers on the relationship between BP parameters and cognitive impairment.

RESULTS

High Aβ uptake was associated with greater mean SBP (β = 1.049, 95% confidence interval 1.016-1.083). High vascular burden was positively associated with mean SBP (odds ratio = 1.293, 95% CI 1.015-1.647) and mean DBP (1.390, 1.098-1.757). High tau uptake was related to greater systolic BPV (0.094, 0.001-0.187) and diastolic BPV (0.096, 0.007-0.184). High Aβ uptake partially mediated the relationship between mean SBP and the Mini-Mental State Examination (MMSE) scores. Hippocampal atrophy mediated the relationship between diastolic BPV and MMSE scores.

CONCLUSIONS

Each BP parameter affects Alzheimer's and vascular disease markers differently, which in turn leads to cognitive impairment. Therefore, it is necessary to appropriately control specific BP parameters to prevent the development of dementia. Furthermore, a better understanding of pathways from specific BP parameters to cognitive impairments might enable us to select the managements targeting the specific BP parameters to prevent dementia effectively.

Under pressure: A systematic review of the association between blood pressure variability with depression and anxiety

Blood pressure variability (BPV) impacts brain health by influencing brain structure and cerebrovascular pathologies, though the mechanisms are poorly understood. Changes in the cerebrovasculature may lead to late-onset depression, cognitive impairment, and dementia, however the relationship between BPV with depression and anxiety remains unclear, due to methodological differences and inconsistencies in past research. This review aims to clarify the association between BPV with depression and anxiety in adults to inform understandings of the mechanisms implicating BPV in cognitive health. A systematic search from inception through to January 2024 was performed on Embase, PubMed, PsycINFO, and Web of Science. Studies that assessed BPV quantified by beat-to-beat, 24-hour, or visit-to-visit were eligible if the standardised assessment of depression and/or anxiety were reported as a linear association, or mean differences across control and affect groups. A total of 14 articles reporting on 13 samples and N = 5055 persons met the inclusion criteria (median female proportion = 61 %, range 0 % - 76 %). A meta-analysis was not possible due to methodological heterogeneity in BPV measurements and metrics across studies. Mixed results were observed across depression studies with inconsistencies and variation in the direction, strength of association, and BPV metric. There was weak evidence from only three studies to support a linear association between systolic coefficient of variation and anxiety. Collectively, the findings contribute to understanding the association between BPV and brain health, suggesting that any relationship between BPV and brain structures critical for cognitive function are independent of depression and only modestly implicate anxiety.

The interactive effect of intra-beat and inter-beat blood pressure variability on neurodegeneration in older adults

Blood pressure variability (BPV) and arterial stiffness are age-related hemodynamic risk factors for neurodegenerative disease, but it remains unclear whether they exert independent or interactive effects on brain health. When combined with high inter-beat BPV, increased intra-beat BPV indicative of arterial stiffness could convey greater pressure wave fluctuations deeper into the cerebrovasculature, exacerbating neurodegeneration. This interactive effect was studied in older adults using multiple markers of neurodegeneration, including medial temporal lobe (MTL) volume, plasma neurofilament light (NfL) and glial fibrillary acidic protein (GFAP). Older adults (N=105) without major neurological or systemic disease were recruited and underwent brain MRI and continuous BP monitoring to quantify inter-beat BPV through systolic average real variability (ARV) and intra-beat variability through arterial stiffness index (ASI). Plasma NfL and GFAP were assessed. The interactive effect of ARV and ASI on MTL atrophy, plasma NfL, and GFAP was studied using hierarchical linear regression. Voxel-based morphometry (VBM) was used to confirm region-of-interest analysis findings. The interaction between higher ARV and higher ASI was significantly associated with left-sided MTL atrophy in both the region-of-interest and false discovery rate-corrected VBM analysis. The interactive effect was also significantly associated with increased plasma NfL, but not GFAP. The interaction between higher ARV and higher ASI is independently associated with increased neurodegenerative markers, including MTL atrophy and plasma NfL, in independently living older adults. Findings could suggest the increased risk for neurodegeneration associated with higher inter-beat BPV may be compounded by increased intra-beat variability due to arterial stiffness.

Reliability of beat-to-beat blood pressure variability in older adults

Blood pressure variability (BPV) is emerging as an important risk factor across numerous disease states, including cerebrovascular and neurodegenerative disease in older adults. However, there is no current consensus regarding specific use cases for the numerous available BPV metrics. There is also little published data supporting the ability to reliably measure BPV across metrics in older adults. BPV metrics were derived from continuous beat-to-beat blood pressure monitoring data. Two sequential 7-minute waveforms were analyzed. Absolute and relative reliability testing was performed. Differences between antihypertensive medication users and non-users on BPV metric reliability was also assessed. All sequence and dispersion based BPV metrics displayed good test-retest reliability. A measure of BP instability displayed only moderate reliability. Systolic and diastolic average real variability displayed the highest levels of reliability at ICC= .87 and .82 respectively. Additionally, systolic average real variability was the most reliable metric in both the antihypertensive use group, and the no antihypertensive use group. Beat-to-beat dispersion and sequence-based metrics of BPV can be reliably obtained from older adults using noninvasive continuous blood pressure monitoring. Average real variability may be the most reliable and specific beat-to-beat blood pressure variability metric due to its decreased susceptibility to outliers and low frequency blood pressure oscillations.

Short-term blood pressure variability and brain functional network connectivity in older adults

Background

Blood pressure variability is increasingly linked with cerebrovascular disease and Alzheimer's disease, independent of mean blood pressure levels. Elevated blood pressure variability is also associated with attenuated cerebrovascular reactivity, which may have implications for functional hyperemia underpinning brain network connectivity. It remains unclear whether blood pressure variability is related to functional network connectivity. We examined relationships between beat-to-beat blood pressure variability and functional connectivity in brain networks vulnerable to aging and Alzheimer's disease.

Methods

53 community-dwelling older adults (mean [SD] age = 69.9 [7.5] years, 62.3% female) without history of dementia or clinical stroke underwent continuous blood pressure monitoring and resting state fMRI scan. Blood pressure variability was calculated as variability independent of mean. Functional connectivity was determined by resting state fMRI for several brain networks: default, salience, dorsal attention, fronto-parietal, and language. Multiple linear regression examined relationships between short-term blood pressure variability and functional network connectivity.

Results

Elevated short-term blood pressure variability was associated with lower functional connectivity in the default network (systolic: standardized ß = -0.30 [95% CI -0.59, -0.01], p = .04). There were no significant associations between blood pressure variability and connectivity in other functional networks or between mean blood pressure and functional connectivity in any network.

Discussion

Older adults with elevated short-term blood pressure variability exhibit lower resting state functional connectivity in the default network. Findings support the role of blood pressure variability in neurovascular dysfunction and Alzheimer's disease. Blood pressure variability may represent an understudied early vascular risk factor for neurovascular dysfunction relevant to Alzheimer's disease, with potential therapeutic implications.

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.

Blood Pressure Variability and Plasma Biomarkers of Neuronal Injury and Alzheimer's Disease: A Clinic-Based Study of Patients with Diseases Along the Heart-Brain Axis

 Higher blood pressure variability (BPV) predisposes to cognitive decline. To investigate underlying mechanisms, we measured 24-h ambulatory BPV, nocturnal dipping and orthostatic hypotension in 518 participants with vascular cognitive impairment, carotid occlusive disease, heart failure, or reference participants. We determined cross-sectional associations between BPV indices and plasma biomarkers of neuronal injury (neurofilament light chain) and Alzheimer's disease (phosphorylated-tau-181 and Aβ42/Aβ40). None of the BPV indices were significantly associated with any of the biomarkers. Hence, in patients with diseases along the heart-brain axis, we found no evidence for an association between BPV and selected markers of neuronal injury or Alzheimer's disease.

Blood pressure variability, central autonomic network dysfunction and cerebral small vessel disease in APOE4 carriers

Background

Increased blood pressure variability (BPV) is a risk factor for cerebral small vessel disease (CSVD) and neurodegeneration, independent of age and average blood pressure, particularly in apolipoprotein E4 (APOE4) carriers. However, it remains uncertain whether BPV elevation is a cause or a consequence of vascular brain injury, or to what degree injury to the central autonomic network (CAN) may contribute to BPV-associated risk in APOE4 carriers.

Methods

Independently living older adults (n=70) with no history of stroke or dementia were recruited from the community and underwent 5 minutes of resting beat-to-beat blood pressure monitoring, genetic testing, and brain MRI. Resting BPV, APOE genotype, CSVD burden on brain MRI, and resting state CAN connectivity by fMRI were analyzed. Causal mediation and moderation analysis evaluated BPV and CAN effects on CSVD in APOE4 carriers (n=37) and non-carriers (n=33).

Results

Higher BPV was associated with the presence and extent of CSVD in APOE4 carriers, but not non-carriers, independent of CAN connectivity (B= 18.92, P= .02), and CAN connectivity did not mediate the relationship between BPV and CSVD. In APOE4 carriers, CAN connectivity moderated the relationship between BPV and CSVD, whereby BPV effects on CSVD were greater in those with lower CAN connectivity (B= 36.43, P= .02).

Conclusions

Older APOE4 carriers with higher beat-to-beat BPV exhibit more extensive CSVD, independent of average blood pressure, and the strength of CAN connectivity does not mediate these effects. Findings suggest increased BPV is more likely a cause, not a consequence, of CSVD. BPV is more strongly associated with CSVD in APOE4 carriers with lower rsCAN connectivity, suggesting CAN dysfunction and BPV elevation may have synergistic effects on CSVD. Further studies are warranted to understand the interplay between BPV and CAN function in APOE4 carriers.

Inferring the genetic relationship between brain imaging-derived phenotypes and risk of complex diseases by Mendelian randomization and genome-wide colocalization

Observational studies consistently disclose brain imaging-derived phenotypes (IDPs) as critical markers for early diagnosis of both brain disorders and cardiovascular diseases. However, it remains unclear about the shared genetic landscape between brain IDPs and the risk of brain disorders and cardiovascular diseases, restricting the applications of potential diagnostic techniques through brain IDPs. Here, we reported genetic correlations and putative causal relationships between 921 brain IDPs, 20 brain disorders and six cardiovascular diseases by leveraging their large-scale genome-wide association study (GWAS) summary statistics. Applications of Mendelian randomization (MR) identified significant putative causal effects of multiple region-specific brain IDPs in relation to the increased risks for amyotrophic lateral sclerosis (ALS), major depressive disorder (MDD), autism spectrum disorder (ASD) and schizophrenia (SCZ). We also found brain IDPs specifically from temporal lobe as a putatively causal consequence of hypertension. The genome-wide colocalization analysis identified three genomic regions in which MDD, ASD and SCZ colocalized with the brain IDPs, and two novel SNPs to be associated with ASD, SCZ, and multiple brain IDPs. Furthermore, we identified a list of candidate genes involved in the shared genetics underlying pairs of brain IDPs and MDD, ASD, SCZ, ALS and hypertension. Our results provide novel insights into the genetic relationships between brain disorders and cardiovascular diseases and brain IDP, which may server as clues for using brain IDPs to predict risks of diseases.

Short-term blood pressure variability is inversely related to regional amplitude of low frequency fluctuations in older and younger adults

Blood pressure variability (BPV), independent of mean blood pressure levels, is associated with cerebrovascular disease burden on MRI and postmortem evaluation. However, less is known about relationships with markers of cerebrovascular dysfunction, such as diminished spontaneous brain activity as measured by the amplitude of low frequency fluctuations (ALFF), especially in brain regions with vascular and neuronal vulnerability in aging. We investigated the relationship between short-term BPV and concurrent regional ALFF from resting state fMRI in a sample of community-dwelling older adults (n = 44) and healthy younger adults (n = 49). In older adults, elevated systolic BPV was associated with lower ALFF in widespread medial temporal regions and the anterior cingulate cortex. Higher systolic BPV in younger adults was also related to lower ALFF in the medial temporal lobe, albeit in fewer subregions, and the amygdala. There were no significant associations between systolic BPV and ALFF across the right/left whole brain or in the insular cortex in either group. Findings suggest a possible regional vulnerability to cerebrovascular dysfunction and short-term fluctuations in blood pressure. BPV may be an understudied risk factor for cerebrovascular changes in aging.

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.

The relationship between long-term blood pressure variability and cortical thickness in older adults

High blood pressure variability (BPV) is a risk factor for cognitive decline and dementia, but its association with cortical thickness is not well understood. Here we use a topographical approach, to assess links between long-term BPV and cortical thickness in 478 (54% men at baseline) community dwelling older adults (70-88 years) from the ASPirin in Reducing Events in the Elderly NEURO sub-study. BPV was measured as average real variability, based on annual visits across three years. Higher diastolic BPV was significantly associated with reduced cortical thickness in multiple areas, including temporal (banks of the superior temporal sulcus), parietal (supramarginal gyrus, post-central gyrus), and posterior frontal areas (pre-central gyrus, caudal middle frontal gyrus), while controlling for mean BP. Higher diastolic BPV was associated with faster progression of cortical thinning across the three years. Diastolic BPV is an important predictor of cortical thickness, and trajectory of cortical thickness, independent of mean blood pressure. This finding suggests an important biological link in the relationship between BPV and cognitive decline in older age.

Blood Pressure Variability in Clinical Practice: Past, Present and the Future

Recent advances in wearable technology through convenient and cuffless systems will enable continuous, noninvasive monitoring of blood pressure (BP), heart rate, and heart rhythm on both longitudinal 24-hour measurement scales and high-frequency beat-to-beat BP variability and synchronous heart rate variability and changes in underlying heart rhythm. Clinically, BP variability is classified into 4 main types on the basis of the duration of monitoring time: very-short-term (beat to beat), short-term (within 24 hours), medium-term (within days), and long-term (over months and years). BP variability is a strong risk factor for cardiovascular diseases, chronic kidney disease, cognitive decline, and mental illness. The diagnostic and therapeutic value of measuring and controlling BP variability may offer critical targets in addition to lowering mean BP in hypertensive populations.

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.

Short- to long-term blood pressure variability: Current evidence and new evaluations

Increased blood pressure (BP) variability and the BP surge have been reported to be associated with increased cardiovascular risk independently of BP levels and can also be a trigger of cardiovascular events. There are multiple types of BP variation: beat-to-beat variations related to breathing and the autonomic nervous system, diurnal BP variation and nocturnal dipping related to sleep and physical activity over a 24-hr period, day-to-day BP variability with anomalous readings within a several-day period, visit-to-visit BP variability between outpatient visits, and seasonal variations. BP variability is also associated with the progression to hypertension from prehypertension and the progression of chronic kidney disease and cognitive impairments. Our research group proposed the "resonance hypothesis of blood pressure surge" as a new etiological hypothesis of BP variability and surges; i.e., the concept that when the time phases of surges and hypertension-inducing environmental influences coincide, resonance occurs and is amplified into a larger "dynamic surge" that triggers the onset of cardiovascular disease. New devices to assess BP variability as well as new therapeutic interventions to reduce BP variability are being developed. Although there are still issues to be addressed (including measurement accuracy), cuffless devices and information and communication technology (ICT)-based BP monitoring devices have been developed and validated. These new devices will be useful for the individualized optimal management of BP. However, evidence regarding the usefulness of therapeutic interventions to control BP variability is still lacking.

Visit-to-Visit Blood Pressure Variability and Cognitive Decline in Apolipoprotein ɛ4 Carriers versus Apolipoprotein ɛ3 Homozygotes

BACKGROUND

Blood pressure variability (BPV) is associated with cognitive decline and Alzheimer's disease (AD), but relationships with AD risk gene apolipoprotein (APOE) ɛ4 remain understudied.

OBJECTIVE

Examined the longitudinal relationship between BPV and cognitive change in APOE ɛ4 carriers and APOE ɛ3 homozygotes.

METHODS

1,194 Alzheimer's Disease Neuroimaging Initiative participants (554 APOE ɛ4 carriers) underwent 3-4 blood pressure measurements between study baseline and 12-month follow-up. Visit-to-visit BPV was calculated as variability independent of mean over these 12 months. Participants subsequently underwent ≥1 neuropsychological exam at 12-month follow-up or later (up to 156 months later). Composite scores for the domains of memory, language, executive function, and visuospatial abilities were determined. Linear mixed models examined the 3-way interaction of BPV×APOE ɛ4 carrier status x time predicting change in composite scores.

RESULTS

Higher systolic BPV predicted greater decline in memory (+1 SD increase of BPV: β= -0.001, p < 0.001) and language (β= -0.002, p < 0.0001) among APOE ɛ4 carriers, but not APOE ɛ3 homozygotes (memory: +1 SD increase of BPV: β= 0.0001, p = 0.57; language: β= 0.0001, p = 0.72). Systolic BPV was not significantly associated with change in executive function or visuospatial abilities in APOE ɛ4 carriers (ps = 0.08-0.16) or APOE ɛ3 homozygotes (ps = 0.48-0.12).

CONCLUSION

Cognitive decline associated with high BPV may be specifically accelerated among APOE ɛ4 carriers.

High visit-to-visit blood pressure variability predicts global cognitive decline: The Multi-Ethnic Study of Atherosclerosis

Background

Research of hypertension-related risk factors for Alzheimer's disease has typically focused on blood pressure (BP) levels, despite evidence that high blood pressure variability (BPV) over time may predict poorer cardiovascular, neuropathological, and neurocognitive outcomes. We evaluated associations between BPV and cognitive function in the Multi-Ethnic Study of Atherosclerosis (MESA).

Methods

Multivariable linear and logistic regression analyses of BP data across six examinations were used to determine associations that BPV (average real variability [ARV], variability independent of the mean [VIM]) and group-based latent BP trajectories have with cognitive function, decline, and impairment, measured by the Cognitive Abilities Screening Instrument (CASI), Digit Symbol Coding (DSC), and Digit Span tests.

Results

Participants (N = 1314; mean baseline age = 57) were 50% female, and 48% White. Higher systolic (β = -0.06, 95% confidence interval [CI]: -0.12, -0.0001) and diastolic (β = -0.08, 95% CI: -0.14, -0.02) ARV predicted increased global cognitive decline after covariate adjustment. Stronger relationships between BPV and global cognition were in older, White and Black participants, apolipoprotein E (APOE) ε4 non-carriers, male participants, and non-antihypertensive medication users.

Conclusion

Results suggest that higher systolic and diastolic BPV is an independent risk factor for cognitive dysfunction and decline in this multi-ethnic cohort. This relationship differs across demographic and clinical characteristics.

The Influence of 24-h Ambulatory Blood Pressure on Cognitive Function and Neuropathological Biomarker in Patients With Alzheimer's Disease

Purpose

This study aimed to investigate the influence of 24-h ambulatory blood pressure (BP) on cognitive function and neuropathological biomarkers in patients with Alzheimer's disease (AD) at the stages of mild cognitive impairment (MCI) and dementia.

Methods

The patients with AD were divided into the MCI (AD-MCI) group and the dementia (AD-D) group. Notably, 24-h BP variables, including BP level, coefficient of variation (CV) of BP, and pulse pressure, were collected and compared between the two groups. The correlations between 24-h BP variables and the scores of cognitive domains were analyzed. The independent influencing factors of cognitive domains of patients with AD were investigated. The levels of neuropathological biomarkers of AD, including β amyloid (Aβ)1−42, phosphorylated tau (P-tau), and total tau (T-tau), in cerebrospinal fluid (CSF) were measured and compared between the two groups, and the correlations between 24-h BP variables and the levels of neuropathological biomarkers of AD were analyzed.

Results

Daytime CV of systolic BP (SBP) was significantly increased in the AD-D group compared to that in the AD-MCI group. The 24-h and daytime CV of SBP and ambulatory pulse pressure were significantly and negatively correlated with memory score. The average 24-h and average daytime SBP level and CV of SBP, daytime CV of diastolic BP (DBP), and 24-h, daytime, and night-time ambulatory pulse pressure were significantly and negatively correlated with language score. The average 24-h SBP level, daytime CV of SBP, and 24-h, daytime, and night-time ambulatory pulse pressure were significantly and negatively correlated with attention score. Further analysis indicated that daytime CV of SBP as well as age and course of disease were the independent influencing factors of language. Age was also the independent influencing factor of memory and attention of patients with AD. T-tau level in CSF in the AD-D group was significantly higher than that in the AD-MCI group, but the levels of Aβ1−42, P-tau, and T-tau in CSF were not correlated with 24-h ambulatory BP variables.

Conclusion

Daytime CV of SBP was the independent influencing factor of language in patients with AD. The AD-D patients had significantly severe neurodegeneration than AD-MCI patients, which was, however, not through the influence of 24-h ambulatory BP variables on neuropathological biomarkers of AD.