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Lohman T, Shenasa F, Sible I, Kapoor A, Engstrom AC, Dutt S, Head E, Sordo L, M Alitin JP, Gaubert A, Nguyen A, Nation DA. The interactive effect of intra-beat and inter-beat blood pressure variability on neurodegeneration in older adults. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.05.01.24306724. [PMID: 38746307 PMCID: PMC11092712 DOI: 10.1101/2024.05.01.24306724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
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.
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Lohman T, Sible IJ, Shenasa F, Engstrom AC, Kapoor A, Alitin JPM, Gaubert A, Thayer JF, Ferrer F, Nation DA. Reliability of beat-to-beat blood pressure variability in older adults. RESEARCH SQUARE 2024:rs.3.rs-4190135. [PMID: 38699342 PMCID: PMC11065081 DOI: 10.21203/rs.3.rs-4190135/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2024]
Abstract
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.
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Affiliation(s)
- Trevor Lohman
- University of Southern California, Leonard Davis School of Gerontology
| | | | | | | | | | | | - Aimee Gaubert
- University of Southern California, Leonard Davis School of Gerontology
| | | | - Farrah Ferrer
- University of Southern California, Leonard Davis School of Gerontology
| | - Daniel A Nation
- University of Southern California, Leonard Davis School of Gerontology
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Hamilton LD, Binns S, McFann K, Nudell N, Dunn JA. A Direct Assessment of Noninvasive Continuous Blood Pressure Monitoring in the Emergency Department and Intensive Care Unit. J Emerg Nurs 2024:S0099-1767(24)00078-3. [PMID: 38639694 DOI: 10.1016/j.jen.2024.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 03/07/2024] [Accepted: 03/08/2024] [Indexed: 04/20/2024]
Abstract
INTRODUCTION Noninvasive continuous blood pressure monitoring has the potential to improve patient treatment in the hospital setting. Such noninvasive devices can be applied earlier in the treatment process to empower nurses and clinicians to react more quickly to patient deterioration with the added benefit of eliminating the risks associated with invasive monitoring. However, emerging technologies must be capable of reproducing current clinical measures for medical decision making. METHODS This study aimed to determine the usability and willingness of nurses to implement a noninvasive continuous blood pressure monitoring device. The secondary aim directly compared the systolic blood pressure, diastolic blood pressure, and mean arterial pressure values recorded by the device (VitalStream; CareTaker Medical LLC, Charlottesville, VA) with the "gold standard" brachial cuff and arterial line measures recorded in the emergency department and intensive care unit settings. RESULTS VitalStream was similarly received by nurses in the emergency department and intensive care setting, but ultimately had greater promotion from emergency nurses. Despite some statistical similarity between measurement methodologies, all direct comparisons were found to not meet the Association for the Advancement of Medical Instrumentation 2008 and Association for the Advancement of Medical Instrumentation / European Society of Hypertension / International Organization for Standardization 2019 consensus statement criteria for acceptable blood pressure measure differences between the VitalStream and "gold standard" clinical measures. In all instances, the standard deviation of the Bland-Altman bias exceeded 8 mm Hg with less than 85% of paired differences falling within 10 mm Hg of the "gold standard." DISCUSSION Taken together, the tested device requires additional postprocessing for medical decision making in trauma or emergent care.
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Sible IJ, Jang JY, Blanken AE, Alitin JPM, Engstrom A, Dutt S, Marshall AJ, Kapoor A, Shenasa F, Gaubert A, Nguyen A, Ferrer F, Bradford DR, Rodgers KE, Mather M, Duke Han S, Nation DA. Short-term blood pressure variability and brain functional network connectivity in older adults. NEUROIMAGE. REPORTS 2024; 4:100198. [PMID: 38699510 PMCID: PMC11064972 DOI: 10.1016/j.ynirp.2024.100198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/05/2024]
Abstract
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.
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Affiliation(s)
- Isabel J. Sible
- Department of Psychology, University of Southern California, Los Angeles, CA 90089, USA
| | - Jung Yun Jang
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA 92697, USA
| | - Anna E. Blanken
- San Francisco Veterans Affairs Health Care System, San Francisco, CA, 94121, USA
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, CA, 94158, USA
| | - John Paul M. Alitin
- Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
| | - Allie Engstrom
- Department of Psychological Science, University of California Irvine, Irvine, CA 92697, USA
| | - Shubir Dutt
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, CA, 94158, USA
| | - Anisa J. Marshall
- Department of Psychology, University of Southern California, Los Angeles, CA 90089, USA
| | - Arunima Kapoor
- Department of Psychological Science, University of California Irvine, Irvine, CA 92697, USA
| | - Fatemah Shenasa
- Department of Psychological Science, University of California Irvine, Irvine, CA 92697, USA
| | - Aimée Gaubert
- Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
| | - Amy Nguyen
- Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
| | - Farrah Ferrer
- Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
| | - David R. Bradford
- Center for Innovation in Brain Science, Department of Pharmacology, The University of Arizona, Tucson, AZ, 85721, USA
| | - Kathleen E. Rodgers
- Center for Innovation in Brain Science, Department of Pharmacology, The University of Arizona, Tucson, AZ, 85721, USA
| | - Mara Mather
- Department of Psychology, University of Southern California, Los Angeles, CA 90089, USA
- Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
| | - S. Duke Han
- Department of Psychology, University of Southern California, Los Angeles, CA 90089, USA
- Department of Family Medicine, Keck School of Medicine of University of Southern California, Alhambra, CA 91803, USA
| | - Daniel A. Nation
- Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
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Sible IJ, Yoo HJ, Min J, Nashiro K, Chang C, Nation DA, Mather M. Short-term blood pressure variability is inversely related to regional amplitude of low frequency fluctuations in older and younger adults. AGING BRAIN 2023; 4:100085. [PMID: 37485296 PMCID: PMC10362312 DOI: 10.1016/j.nbas.2023.100085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Revised: 06/26/2023] [Accepted: 06/29/2023] [Indexed: 07/25/2023] Open
Abstract
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.
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Affiliation(s)
- Isabel J. Sible
- Department of Psychology, University of Southern California, Los Angeles, CA 90089, USA
| | - Hyun Joo Yoo
- Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
| | - Jungwon Min
- Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
| | - Kaoru Nashiro
- Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
| | - Catie Chang
- Department of Electrical and Computer Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - Daniel A. Nation
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, Irvine, CA 92697, USA
- Department of Psychological Science, University of California Irvine, Irvine, CA 92697, USA
| | - Mara Mather
- Department of Psychology, University of Southern California, Los Angeles, CA 90089, USA
- Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
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Bellovary BN, Wells AD, Fennel ZJ, Ducharme JB, Houck JM, Mayschak TJ, Gibson AL, Drum SN, Mermier CM. Could Orthostatic Stress Responses Predict Acute Mountain Sickness Susceptibility Prior to High Altitude Travel? A Pilot Study. High Alt Med Biol 2023; 24:19-26. [PMID: 36473199 DOI: 10.1089/ham.2021.0177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Bellovary, Bryanne N., Andrew D. Wells, Zachary J. Fennel, Jeremy B. Ducharme, Jonathan M. Houck, Trevor J. Mayschak, Ann L. Gibson, Scott N. Drum, and Christine M. Mermier. Could orthostatic stress responses predict acute mountain sickness susceptibility before high altitude travel? A pilot study. High Alt Med Biol. 24:19-26, 2023. Purpose: This study assessed head-up tilt (HUT) responses in relation to acute mountain sickness (AMS)-susceptibility during hypoxic exposure. Materials and Methods: Fifteen participants completed three lab visits: (1) protocol familiarization and cycle maximal oxygen consumption (VO2max) test; (2) HUT test consisting of supine rest for 20 minutes followed by 70° tilting for ≤40 minutes; and (3) 6 hours of hypobaric hypoxic exposure (4,572 m) where participants performed two 30-minute cycling bouts separated by 1 hour at a 50% VO2max workload within the first 3 hours and rested when not exercising. During HUT, systolic blood pressure (SBP), diastolic blood pressure, heart rate (HR), and variability (blood pressure variability [BPV] and HR variability [HRV]) were measured continuously. The AMS scores were determined after 6 hours of exposure. Correlations determined relationships between HUT cardiovascular responses and AMS scores. Repeated-measures analysis of variance (ANOVA) assessed differences between those with and without AMS symptoms during HUT. Results: Higher AMS scores correlated with greater change in SBP variability (r = 0.52, p = 0.048) and blunted changes in HRV (root mean square of successive differences between normal heartbeats r = 0.81, p = 0.001, percentage of adjacent normal sinus intervals that differ by more than 50 milliseconds [pNN50] r = 0.87, p < 0.001) during HUT. A pNN50 interaction (p = 0.02) suggested elevated cardiac sympathetic activity at baseline and a blunted increase in cardiac sympathetic influence throughout HUT in those with AMS (pNN50 baseline: AMS = 26.2% ± 15.3%, no AMS = 51.0% ± 13.5%; first 3 minutes into HUT: AMS = 17.2% ± 19.1%, no AMS = 17.1% ± 10.9%; end of HUT: AMS = 6.2% ± 9.1%, no AMS 11.0% ± 10.0%). Conclusions: The results suggest autonomic responses via HUT differ in AMS-susceptible individuals. Changes in HRV and BPV during HUT may be a promising predictive measurement for AMS-susceptibility, but further research is needed for confirmation.
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Affiliation(s)
- Bryanne N Bellovary
- Kinesiology Department, State University of New York at Cortland, Cortland, New York, USA
- Department of Health, Exercise, and Sport Sciences, University of New Mexico, Albuquerque, New Mexico, USA
| | - Andrew D Wells
- Department of Health, Exercise, and Sport Sciences, University of New Mexico, Albuquerque, New Mexico, USA
- Department of Health and Exercise Science, Wake Forest University, Winston-Salem, North Carolina, USA
| | - Zachary J Fennel
- Department of Health, Exercise, and Sport Sciences, University of New Mexico, Albuquerque, New Mexico, USA
- Molecular Medicine Program, University of Utah, Salt Lake City, Utah, USA
| | - Jeremy B Ducharme
- Department of Health, Exercise, and Sport Sciences, University of New Mexico, Albuquerque, New Mexico, USA
| | - Jonathan M Houck
- Department of Health, Exercise, and Sport Sciences, University of New Mexico, Albuquerque, New Mexico, USA
- Department of Science, Husson University, Bangor, Maine, USA
| | - Trevor J Mayschak
- Department of Health, Exercise, and Sport Sciences, University of New Mexico, Albuquerque, New Mexico, USA
- Department of Emergency Medicine, University of New Mexico, Albuquerque, New Mexico, USA
| | - Ann L Gibson
- Department of Health, Exercise, and Sport Sciences, University of New Mexico, Albuquerque, New Mexico, USA
| | - Scott N Drum
- Department of Health Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Christine M Mermier
- Department of Health, Exercise, and Sport Sciences, University of New Mexico, Albuquerque, New Mexico, USA
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