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Caddy HT, Thomas HJ, Kelsey LJ, Smith KJ, Doyle BJ, Green DJ. Comparison of computational fluid dynamics with transcranial Doppler ultrasound in response to physiological stimuli. Biomech Model Mechanobiol 2024; 23:255-269. [PMID: 37805938 PMCID: PMC10902019 DOI: 10.1007/s10237-023-01772-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 09/05/2023] [Indexed: 10/10/2023]
Abstract
Cerebrovascular haemodynamics are sensitive to multiple physiological stimuli that require synergistic response to maintain adequate perfusion. Understanding haemodynamic changes within cerebral arteries is important to inform how the brain regulates perfusion; however, methods for direct measurement of cerebral haemodynamics in these environments are challenging. The aim of this study was to assess velocity waveform metrics obtained using transcranial Doppler (TCD) with flow-conserving subject-specific three-dimensional (3D) simulations using computational fluid dynamics (CFD). Twelve healthy participants underwent head and neck imaging with 3 T magnetic resonance angiography. Velocity waveforms in the middle cerebral artery were measured with TCD ultrasound, while diameter and velocity were measured using duplex ultrasound in the internal carotid and vertebral arteries to calculate incoming cerebral flow at rest, during hypercapnia and exercise. CFD simulations were developed for each condition, with velocity waveform metrics extracted in the same insonation region as TCD. Exposure to stimuli induced significant changes in cardiorespiratory measures across all participants. Measured absolute TCD velocities were significantly higher than those calculated from CFD (P range < 0.001-0.004), and these data were not correlated across conditions (r range 0.030-0.377, P range 0.227-0.925). However, relative changes in systolic and time-averaged velocity from resting levels exhibited significant positive correlations when the distinct techniques were compared (r range 0.577-0.770, P range 0.003-0.049). Our data indicate that while absolute measures of cerebral velocity differ between TCD and 3D CFD simulation, physiological changes from resting levels in systolic and time-averaged velocity are significantly correlated between techniques.
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Affiliation(s)
- Harrison T Caddy
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, Queen Elizabeth II Medical Centre, Nedlands, Australia and the UWA Centre for Medical Research, The University of Western Australia, Perth, Australia
- School of Human Sciences (Exercise and Sport Sciences), The University of Western Australia, Perth, Australia
| | - Hannah J Thomas
- School of Human Sciences (Exercise and Sport Sciences), The University of Western Australia, Perth, Australia
| | - Lachlan J Kelsey
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, Queen Elizabeth II Medical Centre, Nedlands, Australia and the UWA Centre for Medical Research, The University of Western Australia, Perth, Australia
- School of Engineering, The University of Western Australia, Perth, Australia
| | - Kurt J Smith
- School of Human Sciences (Exercise and Sport Sciences), The University of Western Australia, Perth, Australia
- Cerebrovascular Health, Exercise, and Environmental Research Sciences Laboratory, University of Victoria, Victoria, Canada
| | - Barry J Doyle
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, Queen Elizabeth II Medical Centre, Nedlands, Australia and the UWA Centre for Medical Research, The University of Western Australia, Perth, Australia.
- School of Engineering, The University of Western Australia, Perth, Australia.
| | - Daniel J Green
- School of Human Sciences (Exercise and Sport Sciences), The University of Western Australia, Perth, Australia
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Davydov DM, de la Coba P, Contreras-Merino AM, Reyes Del Paso GA. Impact of homeostatic body hydration status, evaluated by hemodynamic measures, on different pain sensitization paths to a chronic pain syndrome. Sci Rep 2024; 14:1908. [PMID: 38253727 PMCID: PMC10803325 DOI: 10.1038/s41598-024-52419-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 01/18/2024] [Indexed: 01/24/2024] Open
Abstract
Contrasting findings on the mechanisms of chronic pain and hypertension development render the current conventional evidence of a negative relationship between blood pressure (BP) and pain severity insufficient for developing personalized treatments. In this interdisciplinary study, patients with fibromyalgia (FM) exhibiting clinically normal or elevated BP, alongside healthy participants were assessed. Different pain sensitization responses were evaluated using a dynamic 'slowly repeated evoked pain' (SREP) measure, as well as static pain pressure threshold and tolerance measures. Cardiovascular responses to clino-orthostatic (lying-standing) challenges were also examined as acute re- and de-hydration events, challenging cardiovascular and cerebrovascular homeostasis. These challenges involve compensating effects from various cardiac preload or afterload mechanisms associated with different homeostatic body hydration statuses. Additionally, hair cortisol concentration was considered as a factor with an impact on chronic hydration statuses. Pain windup (SREP) and lower pain threshold in FM patients were found to be related to BP rise during clinostatic (lying) rehydration or orthostatic (standing) dehydration events, respectively. These events were determined by acute systemic vasoconstriction (i.e., cardiac afterload response) overcompensating for clinostatic or orthostatic cardiac preload under-responses (low cardiac output or stroke volume). Lower pain tolerance was associated with tonic blood pressure reduction, determined by permanent hypovolemia (low stroke volume) decompensated by permanent systemic vasodilation. In conclusion, the body hydration status profiles assessed by (re)activity of systemic vascular resistance and effective blood volume-related measures can help predict the risk and intensity of different pain sensitization components in chronic pain syndrome, facilitating a more personalized management approach.
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Affiliation(s)
- Dmitry M Davydov
- María Zambrano Senior Scholar, University of Jaén, Campus Las Lagunillas s/n, 23071, Jaén, Spain.
- Laboratory of Neuroimmunopathology, Institute of General Pathology and Pathophysiology, Russian Academy of Sciences, Moscow, Russia.
| | - Pablo de la Coba
- Department of Psychology, University of Extremadura, Badajoz, Spain
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Sagirov AF, Sergeev TV, Shabrov AV, Yurov AY, Guseva NL, Agapova EA. Postural influence on intracranial fluid dynamics: an overview. J Physiol Anthropol 2023; 42:5. [PMID: 37055862 PMCID: PMC10100470 DOI: 10.1186/s40101-023-00323-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 04/01/2023] [Indexed: 04/15/2023] Open
Abstract
This review focuses on the effects of different body positions on intracranial fluid dynamics, including cerebral arterial and venous flow, cerebrospinal fluid (CSF) hydrodynamics, and intracranial pressure (ICP). It also discusses research methods used to quantify these effects. Specifically, the implications of three types of body positions (orthostatic, supine, and antiorthostatic) on cerebral blood flow, venous outflow, and CSF circulation are explored, with a particular emphasis on cerebrovascular autoregulation during microgravity and head-down tilt (HDT), as well as posture-dependent changes in cerebral venous and CSF flow, ICP, and intracranial compliance (ICC). The review aims to provide a comprehensive analysis of intracranial fluid dynamics during different body positions, with the potential to enhance our understanding of intracranial and craniospinal physiology.
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Affiliation(s)
- Arlan Faritovich Sagirov
- Department of Ecological Physiology, Federal State Budgetary Scientific Institution "Institute of Experimental Medicine", 12 Academic Pavlov St, Saint-Petersburg, 197022, Russia.
| | - Timofey Vladimirovich Sergeev
- Department of Ecological Physiology, Federal State Budgetary Scientific Institution "Institute of Experimental Medicine", 12 Academic Pavlov St, Saint-Petersburg, 197022, Russia
| | - Aleksandr Vladimirovich Shabrov
- Department of Ecological Physiology, Federal State Budgetary Scientific Institution "Institute of Experimental Medicine", 12 Academic Pavlov St, Saint-Petersburg, 197022, Russia
| | - Andrey Yur'evich Yurov
- Department of Ecological Physiology, Federal State Budgetary Scientific Institution "Institute of Experimental Medicine", 12 Academic Pavlov St, Saint-Petersburg, 197022, Russia
| | - Nadezhda Leonidovna Guseva
- Department of Ecological Physiology, Federal State Budgetary Scientific Institution "Institute of Experimental Medicine", 12 Academic Pavlov St, Saint-Petersburg, 197022, Russia
| | - Elizaveta Aleksandrovna Agapova
- Department of Ecological Physiology, Federal State Budgetary Scientific Institution "Institute of Experimental Medicine", 12 Academic Pavlov St, Saint-Petersburg, 197022, Russia
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Washio T, Hissen SL, Takeda R, Manabe K, Akins JD, Sanchez B, D'Souza AW, Nelson DB, Khan S, Tomlinson AR, Babb TG, Fu Q. Effects of posture changes on dynamic cerebral autoregulation during early pregnancy in women with obesity and/or sleep apnea. Clin Auton Res 2023; 33:121-131. [PMID: 37115467 DOI: 10.1007/s10286-023-00939-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 03/28/2023] [Indexed: 04/29/2023]
Abstract
The incidence of syncope during orthostasis increases in early human pregnancy, which may be associated with cerebral blood flow (CBF) dysregulation in the upright posture. In addition, obesity and/or sleep apnea per se may influence CBF regulation due to their detrimental impacts on cerebrovascular function. However, it is unknown whether early pregnant women with obesity and/or sleep apnea could have impaired CBF regulation in the supine position and whether this impairment would be further exacerbated in the upright posture. Dynamic cerebral autoregulation (CA) was evaluated using transfer function analysis in 33 women during early pregnancy (13 with obesity, 8 with sleep apnea, 12 with normal weight) and 15 age-matched nonpregnant women during supine rest. Pregnant women also underwent a graded head-up tilt (30° and 60° for 6 min each). We found that pregnant women with obesity or sleep apnea had a higher transfer function low-frequency gain compared with nonpregnant women in the supine position (P = 0.026 and 0.009, respectively) but not normal-weight pregnant women (P = 0.945). Conversely, the transfer function low-frequency phase in all pregnancy groups decreased during head-up tilt (P = 0.001), but the phase was not different among pregnant groups (P = 0.180). These results suggest that both obesity and sleep apnea may have a detrimental effect on dynamic CA in the supine position during early pregnancy. CBF may be more vulnerable to spontaneous blood pressure fluctuations in early pregnant women during orthostatic stress compared with supine rest due to less efficient dynamic CA, regardless of obesity and/or sleep apnea.
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Affiliation(s)
- Takuro Washio
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, 7232 Greenville Avenue, Dallas, TX, 75231, USA
- The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Sarah L Hissen
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, 7232 Greenville Avenue, Dallas, TX, 75231, USA
- The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Ryosuke Takeda
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, 7232 Greenville Avenue, Dallas, TX, 75231, USA
- The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Kazumasa Manabe
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, 7232 Greenville Avenue, Dallas, TX, 75231, USA
- The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - John D Akins
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, 7232 Greenville Avenue, Dallas, TX, 75231, USA
- The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Belinda Sanchez
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, 7232 Greenville Avenue, Dallas, TX, 75231, USA
| | - Andrew W D'Souza
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, 7232 Greenville Avenue, Dallas, TX, 75231, USA
- The University of Texas Southwestern Medical Center, Dallas, TX, USA
- Neurovascular Research Laboratory, School of Kinesiology, Western University, London, ON, Canada
| | - David B Nelson
- The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Safia Khan
- The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Andrew R Tomlinson
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, 7232 Greenville Avenue, Dallas, TX, 75231, USA
- The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Tony G Babb
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, 7232 Greenville Avenue, Dallas, TX, 75231, USA
- The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Qi Fu
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, 7232 Greenville Avenue, Dallas, TX, 75231, USA.
- The University of Texas Southwestern Medical Center, Dallas, TX, USA.
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Rashid T, Li K, Toledo JB, Nasrallah I, Pajewski NM, Dolui S, Detre J, Wolk DA, Liu H, Heckbert SR, Bryan RN, Williamson J, Davatzikos C, Seshadri S, Launer LJ, Habes M. 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. JAMA Netw Open 2023; 6:e231055. [PMID: 36857053 PMCID: PMC9978954 DOI: 10.1001/jamanetworkopen.2023.1055] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/02/2023] Open
Abstract
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.
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Affiliation(s)
- Tanweer Rashid
- Neuroimage Analytics Laboratory and the Biggs Institute Neuroimaging Core, Glenn Biggs Institute for Alzheimer’s and Neurodegenerative Diseases, University of Texas Health Science Center San Antonio, San Antonio
| | - Karl Li
- Neuroimage Analytics Laboratory and the Biggs Institute Neuroimaging Core, Glenn Biggs Institute for Alzheimer’s and Neurodegenerative Diseases, University of Texas Health Science Center San Antonio, San Antonio
| | - Jon B. Toledo
- Department of Neurology, University of Florida, Gainesville
- Department of Neurology, Houston Methodist Hospital, Houston, Texas
| | - Ilya Nasrallah
- Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia
- Center for Biomedical Image Computing and Analytics, University of Pennsylvania, Philadelphia
| | - Nicholas M. Pajewski
- Department of Biostatistics and Data Science, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Sudipto Dolui
- Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia
| | - John Detre
- Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia
- Department of Neurology, University of Pennsylvania, Philadelphia
| | - David A. Wolk
- Department of Neurology, University of Pennsylvania, Philadelphia
| | - Hangfan Liu
- Center for Biomedical Image Computing and Analytics, University of Pennsylvania, Philadelphia
| | | | - R. Nick Bryan
- Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia
| | - Jeff Williamson
- Section of Gerontology and Geriatric Medicine, Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Christos Davatzikos
- Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia
- Center for Biomedical Image Computing and Analytics, University of Pennsylvania, Philadelphia
| | - Sudha Seshadri
- Neuroimage Analytics Laboratory and the Biggs Institute Neuroimaging Core, Glenn Biggs Institute for Alzheimer’s and Neurodegenerative Diseases, University of Texas Health Science Center San Antonio, San Antonio
| | - Lenore J. Launer
- Intramural Research Program, Laboratory of Epidemiology and Population Sciences, National Institute on Aging, National Institutes of Health, Bethesda, Maryland
| | - Mohamad Habes
- Neuroimage Analytics Laboratory and the Biggs Institute Neuroimaging Core, Glenn Biggs Institute for Alzheimer’s and Neurodegenerative Diseases, University of Texas Health Science Center San Antonio, San Antonio
- Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia
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Paré M, Obeid H, Labrecque L, Drapeau A, Brassard P, Agharazii M. Cerebral blood flow pulsatility and cerebral artery stiffness acutely decrease during hemodialysis. Physiol Rep 2023; 11:e15595. [PMID: 36808481 PMCID: PMC9937783 DOI: 10.14814/phy2.15595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 01/19/2023] [Indexed: 02/19/2023] Open
Abstract
End-stage kidney disease (ESKD) is associated with increased arterial stiffness and cognitive impairment. Cognitive decline is accelerated in ESKD patients on hemodialysis and may result from repeatedly inappropriate cerebral blood flow (CBF). The aim of this study was to examine the acute effect of hemodialysis on pulsatile components of CBF and their relation to acute changes in arterial stiffness. In eight participants (age: 63 ± 18 years, men: 5), CBF was estimated using middle cerebral artery blood velocity (MCAv) assessed with transcranial Doppler ultrasound before, during, and after a single hemodialysis session. Brachial and central blood pressure, along with estimated aortic stiffness (eAoPWV) were measured using an oscillometric device. Arterial stiffness from heart to MCA was measured as the pulse arrival time (PAT) between electrocardiogram (ECG) and transcranial Doppler ultrasound waveforms (cerebral PAT). During hemodialysis, there was a significant reduction in mean MCAv (-3.2 cm/s, p < 0.001), and systolic MCAv (-13.0 cm/s, p < 0.001). While baseline eAoPWV (9.25 ± 0.80 m/s) did not significantly change during hemodialysis, cerebral PAT increased significantly (+0.027 , p < 0.001) and was associated with reduced pulsatile components of MCAv. This study shows that hemodialysis acutely reduces stiffness of arteries perfusing the brain along with pulsatile components of blood velocity.
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Affiliation(s)
- Mathilde Paré
- CHU de Québec Research Center, L'Hôtel‐Dieu de Québec HospitalQuébec CityQuebecCanada,Research Center of the Institute Universitaire de Cardiologie et de Pneumologie de QuébecQuébec CityQuebecCanada,Department of Kinesiology, Faculty of MedicineUniversité LavalQuébec CityQuebecCanada
| | - Hasan Obeid
- CHU de Québec Research Center, L'Hôtel‐Dieu de Québec HospitalQuébec CityQuebecCanada
| | - Lawrence Labrecque
- Research Center of the Institute Universitaire de Cardiologie et de Pneumologie de QuébecQuébec CityQuebecCanada,Department of Kinesiology, Faculty of MedicineUniversité LavalQuébec CityQuebecCanada
| | - Audrey Drapeau
- Research Center of the Institute Universitaire de Cardiologie et de Pneumologie de QuébecQuébec CityQuebecCanada,Department of Kinesiology, Faculty of MedicineUniversité LavalQuébec CityQuebecCanada
| | - Patrice Brassard
- Research Center of the Institute Universitaire de Cardiologie et de Pneumologie de QuébecQuébec CityQuebecCanada,Department of Kinesiology, Faculty of MedicineUniversité LavalQuébec CityQuebecCanada
| | - Mohsen Agharazii
- CHU de Québec Research Center, L'Hôtel‐Dieu de Québec HospitalQuébec CityQuebecCanada,Division of Nephrology, Faculty of MedicineUniversité Laval, QuébecQuébec CityQuebecCanada
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Whittle RS, Diaz-Artiles A. Gravitational effects on carotid and jugular characteristics in graded head-up and head-down tilt. J Appl Physiol (1985) 2023; 134:217-229. [PMID: 36476158 PMCID: PMC9870583 DOI: 10.1152/japplphysiol.00248.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Revised: 11/23/2022] [Accepted: 12/06/2022] [Indexed: 12/13/2022] Open
Abstract
Altered gravity affects hemodynamics and blood flow in the neck. At least one incidence of jugular venous thrombosis has been reported in an astronaut on the International Space Station. This investigation explores the impact of changes in the direction of the gravitational vector on the characteristics of the neck arteries and veins. Twelve subjects underwent graded tilt from 45° head-up to 45° head-down in 15° increments in both supine and prone positions. At each angle, the cross-sectional area of the left and right common carotid arteries (ACCA) and internal jugular veins (AIJV) were measured by ultrasound. Internal jugular venous pressure (IJVP) was also measured by compression sonography. Gravitational dose-response curves were generated from experimental data. ACCA did not show any gravitational dependence. Conversely, both AIJV and IJVP increased in a nonlinear fashion with head-down tilt. AIJV was significantly larger on the right side than the left side at all tilt angles. In addition, IJVP was significantly elevated in the prone position compared with the supine position, most likely because of raised intrathoracic pressure while prone. Dose-response curves were compared with existing experimental data from parabolic flight and spaceflight studies, showing good agreement on an acute timescale. The quantification of jugular hemodynamics as a function of changes in the gravitational vector presented here provides a terrestrial model to reference spaceflight-induced changes, contributes to the assessment of the pathogenesis of spaceflight venous thromboembolism events, and informs the development of countermeasures.NEW & NOTEWORTHY Flow stasis and thrombosis have been identified in the jugular vein during spaceflight. We measured the area and pressure of the internal jugular vein and the area of the common carotid artery in graded head-up and head-down tilt. Experimental data are used to generate gravitational dose-response curves for the measured variables, demonstrating that jugular vein area and pressure exhibit a nonlinear response to altered gravity. Gravitational dose-response curves show good agreement with spaceflight and parabolic flight studies.
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Affiliation(s)
- Richard S Whittle
- Department of Aerospace Engineering, Texas A&M University, College Station, Texas
| | - Ana Diaz-Artiles
- Department of Aerospace Engineering, Texas A&M University, College Station, Texas
- Department of Kinesiology & Sport Management, Texas A&M University, College Station, Texas
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Validity of transcranial Doppler ultrasonography-determined dynamic cerebral autoregulation estimated using transfer function analysis. J Clin Monit Comput 2022; 36:1711-1721. [PMID: 35075510 DOI: 10.1007/s10877-022-00817-1] [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: 04/12/2021] [Accepted: 01/19/2022] [Indexed: 10/19/2022]
Abstract
Transcranial Doppler ultrasonography (TCD) is used widely to evaluate dynamic cerebral autoregulation (dCA). However, the validity of TCD-determined dCA remains unknown because TCD is only capable of measuring blood velocity and thus only provides an index as opposed to true blood flow. To test the validity of TCD-determined dCA, in nine healthy subjects, dCA was evaluated by transfer function analysis (TFA) using cerebral blood flow (CBF) or TCD-measured cerebral blood velocity during a perturbation that induces reductions in TCD-determined dCA, lower body negative pressure (LBNP) at two different stages: LBNP - 15 mmHg and - 50 mmHg. Internal carotid artery blood flow (ICA Q) was assessed as an index of CBF using duplex Doppler ultrasound. The TFA low frequency (LF) normalized gain (ngain) calculated using ICA Q increased during LBNP at - 50 mmHg (LBNP50) from rest (P = 0.005) and LBNP at - 15 mmHg (LBNP15) (P = 0.015), indicating an impaired dCA. These responses were the same as those obtained using TCD-measured cerebral blood velocity (from rest and LBNP15; P = 0.001 and P = 0.015). In addition, the ICA Q-determined TFA LF ngain from rest to LBNP50 was significantly correlated with TCD-determined TFA LF ngain (r = 0.460, P = 0.016) despite a low intraclass correlation coefficient. Moreover, in the Bland-Altman analysis, the difference in the TFA LF ngains determined by blood flow and velocity was within the margin of error, indicating that the two measurement methods can be interpreted as equivalent. These findings suggest that TCD-determined dCA can be representative of actual dCA evaluated with CBF.
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Olesen ND, Egesborg AH, Frederiksen HJ, Kitchen CC, Svendsen LB, Olsen NV, Secher NH. Influence of blood pressure on internal carotid artery blood flow during combined propofol-remifentanil and thoracic epidural anesthesia. J Anaesthesiol Clin Pharmacol 2022; 38:580-587. [PMID: 36778814 PMCID: PMC9912875 DOI: 10.4103/joacp.joacp_575_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 04/14/2021] [Accepted: 05/14/2021] [Indexed: 12/31/2022] Open
Abstract
Background and Aims Anesthesia often reduces mean arterial pressure (MAP) to a level that may compromise cerebral blood flow. We evaluated whether phenylephrine treatment of anesthesia-induced hypotension affects internal carotid artery (ICA) blood flow and whether anesthesia affects ICA flow and CO2 reactivity. Material and Methods The study included twenty-seven patients (65 ± 11 years; mean ± SD) undergoing esophageal resection (n = 14), stomach resection (n = 12), or a gastroentero anastomosis (n = 1) during combined propofol-remifentanil and thoracic epidural anesthesia. Duplex ultrasound evaluated ICA blood flow. Evaluations were before and after induction of anesthesia, before and after the administration of phenylephrine as part of standard care to treat anesthesia-induced hypotension at a MAP below 60 mmHg, and the hypocapnic reactivity of ICA flow was determined before and during anesthesia. Results Induction of anesthesia reduced MAP from 108 ± 12 to 66 ± 16 mmHg (P < 0.0001) and ICA flow from 340 ± 92 to 196 ± 52 mL/min (P < 0.0001). Phenylephrine was administered to 24 patients (0.1-0.2 mg) and elevated MAP from 53 ± 8 to 73 ± 8 mmHg (P = 0.0001) and ICA flow from 191 ± 43 to 218 ± 50 mL/min (P = 0.0276). Furthermore, anesthesia reduced the hypocapnic reactivity of ICA flow from 23 (18-33) to 14%/kPa (10-22; P = 0.0068). Conclusion Combined propofol-remifentanil and thoracic epidural anesthesia affect ICA flow and CO2 reactivity. Phenylephrine partly restored ICA flow indicating that anesthesia-induced hypotension contributes to the reduction in ICA flow.
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Affiliation(s)
- Niels D. Olesen
- Department of Anesthesia, Rigshospitalet, University of Copenhagen, Copenhagen, Blegdamsvej 9, DK-2100 Copenhagen Ø, Denmark
- Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200, Copenhagen N, Denmark
| | - Astrid H. Egesborg
- Department of Anesthesia, Rigshospitalet, University of Copenhagen, Copenhagen, Blegdamsvej 9, DK-2100 Copenhagen Ø, Denmark
| | - Hans-Jørgen Frederiksen
- Department of Anesthesia, Rigshospitalet, University of Copenhagen, Copenhagen, Blegdamsvej 9, DK-2100 Copenhagen Ø, Denmark
| | - Carl-Christian Kitchen
- Department of Anesthesia, Rigshospitalet, University of Copenhagen, Copenhagen, Blegdamsvej 9, DK-2100 Copenhagen Ø, Denmark
| | - Lars B. Svendsen
- Department of Surgical Gastroenterology, Rigshospitalet, University of Copenhagen, Copenhagen, Blegdamsvej 9, DK-2100 Copenhagen Ø, Denmark
| | - Niels V. Olsen
- Department of Anesthesia, Rigshospitalet, University of Copenhagen, Copenhagen, Blegdamsvej 9, DK-2100 Copenhagen Ø, Denmark
- Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200, Copenhagen N, Denmark
| | - Niels H. Secher
- Department of Anesthesia, Rigshospitalet, University of Copenhagen, Copenhagen, Blegdamsvej 9, DK-2100 Copenhagen Ø, Denmark
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10
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Saehle T. Cerebral Hemodynamics During Exposure to Hypergravity (+G z) or Microgravity (0 G). Aerosp Med Hum Perform 2022; 93:581-592. [DOI: 10.3357/amhp.6008.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
BACKGROUND: Optimal human performance and health is dependent on steady blood supply to the brain. Hypergravity (+Gz) may impair cerebral blood flow (CBF), and several investigators have also reported that microgravity (0 G) may influence cerebral hemodynamics. This
has led to concerns for safe performance during acceleration maneuvers in aviation or the impact long-duration spaceflights may have on astronaut health.METHODS: A systematic PEO (Population, Exposure, Outcome) search was done in PubMed and Web of Science, addressing studies on
how elevated +Gz forces or absence of such may impact cerebral hemodynamics. All primary research containing anatomical or physiological data on relevant intracranial parameters were included. Quality of the evidence was analyzed using the GRADE tool.RESULTS: The search
revealed 92 eligible articles. It is evident that impaired CBF during +Gz acceleration remains an important challenge in aviation, but there are significant variations in individual tolerance. The reports on cerebral hemodynamics during weightlessness are inconsistent, but published
data indicate that adaptation to sustained microgravity is also characterized by significant variations among individuals.DISCUSSION: Despite a high number of publications, the quality of evidence is limited due to observational study design, too few included subjects, and methodological
challenges. Clinical consequences of high +Gz exposure are well described, but there are significant gaps in knowledge regarding the intracranial pathophysiology and individual hemodynamic tolerance to both hypergravity and microgravity environments.Saehle T. Cerebral
hemodynamics during exposure to hypergravity (+Gz) or microgravity (0 G). Aerosp Med Hum Perform. 2022; 93(7):581–592.
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11
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Chacón M, Rojas-Pescio H, Peñaloza S, Landerretche J. Machine Learning Models and Statistical Complexity to Analyze the Effects of Posture on Cerebral Hemodynamics. ENTROPY 2022; 24:e24030428. [PMID: 35327938 PMCID: PMC8947420 DOI: 10.3390/e24030428] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 03/09/2022] [Accepted: 03/16/2022] [Indexed: 02/05/2023]
Abstract
The mechanism of cerebral blood flow autoregulation can be of great importance in diagnosing and controlling a diversity of cerebrovascular pathologies such as vascular dementia, brain injury, and neurodegenerative diseases. To assess it, there are several methods that use changing postures, such as sit-stand or squat-stand maneuvers. However, the evaluation of the dynamic cerebral blood flow autoregulation (dCA) in these postures has not been adequately studied using more complex models, such as non-linear ones. Moreover, dCA can be considered part of a more complex mechanism called cerebral hemodynamics, where others (CO2 reactivity and neurovascular-coupling) that affect cerebral blood flow (BF) are included. In this work, we analyzed postural influences using non-linear machine learning models of dCA and studied characteristics of cerebral hemodynamics under statistical complexity using eighteen young adult subjects, aged 27 ± 6.29 years, who took the systemic or arterial blood pressure (BP) and cerebral blood flow velocity (BFV) for five minutes in three different postures: stand, sit, and lay. With models of a Support Vector Machine (SVM) through time, we used an AutoRegulatory Index (ARI) to compare the dCA in different postures. Using wavelet entropy, we estimated the statistical complexity of BFV for three postures. Repeated measures ANOVA showed that only the complexity of lay-sit had significant differences.
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Affiliation(s)
- Max Chacón
- Departamento de Ingeniería Informática, Universidad de Santiago de Chile, Av. Víctor Jara N° 2659, Estación Central, Santiago 9190864, Chile; (H.R.-P.); (S.P.)
- Correspondence:
| | - Hector Rojas-Pescio
- Departamento de Ingeniería Informática, Universidad de Santiago de Chile, Av. Víctor Jara N° 2659, Estación Central, Santiago 9190864, Chile; (H.R.-P.); (S.P.)
| | - Sergio Peñaloza
- Departamento de Ingeniería Informática, Universidad de Santiago de Chile, Av. Víctor Jara N° 2659, Estación Central, Santiago 9190864, Chile; (H.R.-P.); (S.P.)
| | - Jean Landerretche
- Unidad de Neurología, Escuela de Medicina, Universidad de Santiago de Chile, Av. Alameda N° 3336, Estación Central, Santiago 9170022, Chile;
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12
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Horiuchi M, Rossetti GM, Oliver SJ. Dietary nitrate supplementation effect on dynamic cerebral autoregulation in normoxia and acute hypoxia. J Cereb Blood Flow Metab 2022; 42:486-494. [PMID: 32151227 PMCID: PMC8985441 DOI: 10.1177/0271678x20910053] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
We tested the hypothesis that increasing the nitric oxide (NO) bioavailability by dietary nitrate would recover the hypoxia-induced reduction in dynamic cerebral autoregulation (CA). Twelve healthy males (age 21 ± 2 years) completed four days of dietary supplementation with a placebo or inorganic nitrate drink (140-ml beetroot juice per day) followed by 60-min of normoxia or hypoxia (fraction of inspired oxygen [FiO2] = 13%). Duplex ultrasonography was used to perform volumetric change-based assessment of dynamic CA in the internal carotid artery (ICA). Dynamic CA was assessed by rate of regulation (RoR) of vascular conductance using the thigh-cuff method. Four days of beetroot supplementation increased circulating nitrate by 208 [171,245] μM (mean difference [95% confidence interval]) compared with placebo. Dynamic CA was lower in hypoxia than normoxia (RoR Δ-0.085 [-0.116, -0.054]). Compared with placebo, nitrate did not alter dynamic CA in normoxia (RoR Δ-0.022 [-0.060, 0.016]) or hypoxia (RoR Δ0.017 [-0.019, 0.053]). Further, nitrate did not affect ICA vessel diameter, blood velocity or flow in either normoxia or hypoxia. Increased bioavailability of NO through dietary nitrate supplementation did not recover the hypoxia-induced reduction in dynamic CA. This suggests the mechanism of hypoxia-induced reduction in dynamic CA does not relate to the availability of NO.
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Affiliation(s)
- Masahiro Horiuchi
- Division of Human Environmental Science, Mt. Fuji Research Institute, Fujiyoshida, Japan
| | - Gabriella Mk Rossetti
- Extremes Research Group, College of Human Sciences, Bangor University, Bangor, Wales
| | - Samuel J Oliver
- Extremes Research Group, College of Human Sciences, Bangor University, Bangor, Wales
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13
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Washio T, Watanabe H, Suzuki K, Saito S, Ogoh S. Site-specific different dynamic cerebral autoregulation and cerebrovascular response to carbon dioxide in posterior cerebral circulation during isometric exercise in healthy young men. Auton Neurosci 2022; 238:102943. [PMID: 35086019 DOI: 10.1016/j.autneu.2022.102943] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 11/16/2021] [Accepted: 01/16/2022] [Indexed: 11/23/2022]
Abstract
Different cerebral blood flow (CBF) responses to exercise between the posterior cerebral artery (PCA) and vertebral artery (VA) have been previously observed, though the physiological mechanisms remain unknown. There is regional heterogeneity in sympathetic innervation between the PCA and VA, which may affect CBF regulation, especially during sympathoexcitation. Thus, in the present study, we hypothesized that different CBF regulatory mechanisms between PCA and VA contribute to heterogeneous CBF responses to isometric exercise. To test this hypothesis, in thirteen healthy young men, dynamic cerebral autoregulation (CA) and cerebrovascular CO2 reactivity (CVR), were identified in each artery during a 2-min isometric handgrip (IHG) exercise at 30% of maximum voluntary contraction. Similar to previous data, PCA cerebrovascular conductance (CVC) index was decreased from rest (P < 0.004), but not VA CVC during IHG exercise (P > 0.084). Dynamic CA in both PCA and VA were unaltered during the IHG exercise (P = 0.129). On the other hand, PCA CVR was increased during the IHG exercise (P < 0.001) while VA CVR was unchanged (P = 0.294). In addition, individual exercise-induced changes in end-tidal partial pressure of CO2 was related to the individual change in PCA blood velocity (P < 0.046), but was not observed for VA blood flow (P > 0.420). Therefore, these exercise-induced differences in CVR between PCA and VA may contribute to exercise-induced heterogeneous CBF response in the posterior cerebral circulation. These findings indicate that the site-specific posterior CBF should be considered in further research for assessing posterior cerebral circulation.
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Affiliation(s)
- Takuro Washio
- Department of Biomedical Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan
| | - Hironori Watanabe
- Department of Biomedical Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan
| | - Kazuya Suzuki
- Department of Biomedical Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan
| | - Shotaro Saito
- Department of Biomedical Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan
| | - Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan; Neurovascular Research Laboratory, University of South Wales, UK.
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14
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Watanabe H, Saito S, Washio T, Bailey DM, Ogoh S. Acute Gravitational Stress Selectively Impairs Dynamic Cerebrovascular Reactivity in the Anterior Circulation Independent of Changes to the Central Respiratory Chemoreflex. Front Physiol 2022; 12:749255. [PMID: 35069233 PMCID: PMC8770752 DOI: 10.3389/fphys.2021.749255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 12/03/2021] [Indexed: 11/13/2022] Open
Abstract
Cerebrovascular reactivity (CVR) to changes in the partial pressure of arterial carbon dioxide (PaCO2) is an important mechanism that maintains CO2 or pH homeostasis in the brain. To what extent this is influenced by gravitational stress and corresponding implications for the regulation of cerebral blood flow (CBF) remain unclear. The present study examined the onset responses of pulmonary ventilation (V̇E) and anterior middle (MCA) and posterior (PCA) cerebral artery mean blood velocity (Vmean) responses to acute hypercapnia (5% CO2) to infer dynamic changes in the central respiratory chemoreflex and cerebrovascular reactivity (CVR), in supine and 50° head-up tilt (HUT) positions. Each onset response was evaluated using a single-exponential regression model consisting of the response time latency [CO2-response delay (t0)] and time constant (τ). Onset response of V̇E and PCA Vmean to changes in CO2 was unchanged during 50° HUT compared with supine (τ: V̇E, p = 0.707; PCA Vmean, p = 0.071 vs. supine) but the MCA Vmean onset response was faster during supine than during 50° HUT (τ: p = 0.003 vs. supine). These data indicate that gravitational stress selectively impaired dynamic CVR in the anterior cerebral circulation, whereas the posterior circulation was preserved, independent of any changes to the central respiratory chemoreflex. Collectively, our findings highlight the regional heterogeneity underlying CBF regulation that may have translational implications for the microgravity (and hypercapnia) associated with deep-space flight notwithstanding terrestrial orthostatic diseases that have been linked to accelerated cognitive decline and neurodegeneration.
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Affiliation(s)
- Hironori Watanabe
- Department of Biomedical Engineering, Toyo University, Kawagoe, Japan
| | - Shotaro Saito
- Department of Biomedical Engineering, Toyo University, Kawagoe, Japan
| | - Takuro Washio
- Department of Biomedical Engineering, Toyo University, Kawagoe, Japan.,Research Fellow of Japan Society for the Promotion of Science, Tokyo, Japan
| | - Damian Miles Bailey
- Research Fellow of Japan Society for the Promotion of Science, Tokyo, Japan.,Neurovascular Research Laboratory, University of South Wales, Pontypridd, United Kingdom
| | - Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, Kawagoe, Japan.,Neurovascular Research Laboratory, University of South Wales, Pontypridd, United Kingdom
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15
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Ikidag MA, Firat YE. Comparison of carotid and vertebral artery doppler measurements in supine and sitting positions. Niger J Clin Pract 2022; 25:1883-1888. [DOI: 10.4103/njcp.njcp_326_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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16
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Matsumura Y, Yamanaka T, Murai T, Fujita N, Kitahara T. Orthostatic hemodynamics in the vertebral artery and blood pressure in patients with orthostatic dizziness/vertigo. Auris Nasus Larynx 2021; 49:593-598. [PMID: 34930632 DOI: 10.1016/j.anl.2021.12.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 11/07/2021] [Accepted: 12/02/2021] [Indexed: 02/03/2023]
Abstract
OBJECTIVES Orthostatic dizziness/vertigo (ODV) is a common symptom and is believed to occur due to the cerebral hypoperfusion caused by orthostatic hypotension (OH). However, the detailed mechanism underlying ODV onset is poorly understood. The vertebral artery (VA) mainly supplies blood to the central vestibular system; therefore, the orthostatic decrease of VA blood flow could possibly lead to ODV. This study investigated the orthostatic blood pressure and VA hemodynamics in ODV patients to elucidate the hemodynamic mechanism underlying ODV onset. Furthermore, the influence of orthostatic hypotension (OH) on VA hemodynamics was examined because OH is probably the most common cause of ODV. METHODS This study included 181 patients with ODV and 73 control patients without ODV. All subjects underwent an active standing test to measure the extracranial Doppler (ECD) sonography spectrum of the VA and blood pressure (BP). VA blood flow velocity and BP were simultaneously measured for each patient in the supine static position and then in the upright standing positions following 3 min of standing. We investigated the orthostatic change in the average of flow velocity in bilateral VAs (VAFV) and BP for ODV patients compared with the control patients. RESULT VAFV in ODV patients was significantly reduced when standing up compared with the control patients. In the ODV patients, there was no difference in orthostatic decrease in VAFV between patients those with OH and without OH. However, the VAFV in the standing position was significantly lower in patients with OH than without OH. In cases with OH, the ODV patients exhibited a greater decrease in VAFV compared with the control patients, but this was not statistically significant. In the absence of OH, a significantly greater orthostatic decrease in VAFV was observed in ODV patients compared with the controls. CONCLUSION Our findings suggest that the orthostatic decrease of VA blood flow is deeply involved in the hemodynamic mechanism underlying ODV onset and is possibly associated with OH and other etiologies.
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Affiliation(s)
- Yachiyo Matsumura
- Department of Otolaryngology-Head and Neck Surgery, Nara Medical University School of Medicine Address: 840 Shijo, Kashihara Nara, 634-8522, Japan
| | - Toshiaki Yamanaka
- Department of Otolaryngology-Head and Neck Surgery, Nara Medical University School of Medicine Address: 840 Shijo, Kashihara Nara, 634-8522, Japan..
| | - Takayuki Murai
- Department of Otolaryngology-Head and Neck Surgery, Nara Medical University School of Medicine Address: 840 Shijo, Kashihara Nara, 634-8522, Japan
| | - Nobuya Fujita
- Department of Otorhinolaryngology, Osaka Kaisei Hospital, Address: 1-6-10 Miyahara, Yodogawa-ku, Osaka, 532-0003, Japan
| | - Tadashi Kitahara
- Department of Otolaryngology-Head and Neck Surgery, Nara Medical University School of Medicine Address: 840 Shijo, Kashihara Nara, 634-8522, Japan
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17
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Koep JL, Taylor CE, Coombes JS, Bond B, Ainslie PN, Bailey TG. Autonomic control of cerebral blood flow: fundamental comparisons between peripheral and cerebrovascular circulations in humans. J Physiol 2021; 600:15-39. [PMID: 34842285 DOI: 10.1113/jp281058] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 11/25/2021] [Indexed: 01/12/2023] Open
Abstract
Understanding the contribution of the autonomic nervous system to cerebral blood flow (CBF) control is challenging, and interpretations are unclear. The identification of calcium channels and adrenoreceptors within cerebral vessels has led to common misconceptions that the function of these receptors and actions mirror those of the peripheral vasculature. This review outlines the fundamental differences and complex actions of cerebral autonomic activation compared with the peripheral circulation. Anatomical differences, including the closed nature of the cerebrovasculature, and differential adrenoreceptor subtypes, density, distribution and sensitivity, provide evidence that measures on peripheral sympathetic nerve activity cannot be extrapolated to the cerebrovasculature. Cerebral sympathetic nerve activity seems to act opposingly to the peripheral circulation, mediated at least in part by changes in intracranial pressure and cerebral blood volume. Additionally, heterogeneity in cerebral adrenoreceptor distribution highlights region-specific autonomic regulation of CBF. Compensatory chemo- and autoregulatory responses throughout the cerebral circulation, and interactions with parasympathetic nerve activity are unique features to the cerebral circulation. This crosstalk between sympathetic and parasympathetic reflexes acts to ensure adequate perfusion of CBF to rising and falling perfusion pressures, optimizing delivery of oxygen and nutrients to the brain, while attempting to maintain blood volume and intracranial pressure. Herein, we highlight the distinct similarities and differences between autonomic control of cerebral and peripheral blood flow, and the regional specificity of sympathetic and parasympathetic regulation within the cerebrovasculature. Future research directions are outlined with the goal to further our understanding of autonomic control of CBF in humans.
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Affiliation(s)
- Jodie L Koep
- Physiology and Ultrasound Laboratory in Science and Exercise, Centre for Research on Exercise, Physical Activity and Health, School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, Queensland, Australia.,Children's Health and Exercise Research Centre, Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Chloe E Taylor
- School of Health Sciences, Western Sydney University, Sydney, Australia
| | - Jeff S Coombes
- Physiology and Ultrasound Laboratory in Science and Exercise, Centre for Research on Exercise, Physical Activity and Health, School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Bert Bond
- Children's Health and Exercise Research Centre, Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
| | - Tom G Bailey
- Physiology and Ultrasound Laboratory in Science and Exercise, Centre for Research on Exercise, Physical Activity and Health, School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, Queensland, Australia.,School of Nursing, Midwifery and Social Work, The University of Queensland, Brisbane, Queensland, Australia
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18
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Watanabe H, Washio T, Saito S, Ogoh S. Effect of breath-hold on the responses of arterial blood pressure and cerebral blood velocity to isometric exercise. Eur J Appl Physiol 2021; 122:157-168. [PMID: 34618221 DOI: 10.1007/s00421-021-04822-1] [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: 04/07/2021] [Accepted: 09/25/2021] [Indexed: 12/01/2022]
Abstract
PURPOSE The present study examined the effect of breath-hold without a Valsalva maneuver during isometric exercise on arterial blood pressure (ABP) and cerebral blood flow (CBF). METHODS Twenty healthy adults (15 men and five women) randomly performed only breath-hold without a Valsalva maneuver (BH), and an isometric handgrip exercise for 30 s at 40% of individual maximal voluntary contraction with continuous breathing (IHG) and with breath-hold without the Valsalva maneuver (IHG-BH). Mean ABP (MAP) and blood velocity in the middle (MCA Vmean) and posterior cerebral arteries (PCA Vmean) were continuously measured throughout each protocol. RESULTS MAP was elevated during the IHG-BH compared with IHG (P < 0.001) and BH (P = 0.001). Similarly, both MCA Vmean and PCA Vmean were higher during IHG-BH compared with IHG and BH (all P < 0.001). Moreover, the relative change in MAP from the baseline was correlated with that in both cerebral blood velocities during the BH (MCA Vmean: r = 0.739, P < 0.001 and PCA Vmean: r = 0.570, P = 0.009) and IHG-BH (MCA Vmean: r = 0.755, P < 0.001 and PCA Vmean: r = 0.617, P = 0.003) condition, but not the IHG condition (P = 0.154 and P = 0.306). CONCLUSION These results indicate that during isometric exercise, a breath-hold enhances an exercise-induced increase in MAP and, consequently, MCA Vmean and PCA Vmean.
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Affiliation(s)
- Hironori Watanabe
- Department of Biomedical Engineering, Toyo University, 2100 Kujirai, Kawagoe-shi, Saitama, 350-8585, Japan
| | - Takuro Washio
- Department of Biomedical Engineering, Toyo University, 2100 Kujirai, Kawagoe-shi, Saitama, 350-8585, Japan.,Japan Society for the Promotion of Science, Tokyo, Japan
| | - Shotaro Saito
- Department of Biomedical Engineering, Toyo University, 2100 Kujirai, Kawagoe-shi, Saitama, 350-8585, Japan
| | - Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, 2100 Kujirai, Kawagoe-shi, Saitama, 350-8585, Japan. .,Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK.
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19
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Fong D, Gradon K, Barrett CJ, Guild SJ, Tzeng YC, Paton JFR, McBryde FD. A method to evaluate dynamic cerebral pressure-flow relationships in the conscious rat. J Appl Physiol (1985) 2021; 131:1361-1369. [PMID: 34498945 DOI: 10.1152/japplphysiol.00289.2021] [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: 11/22/2022] Open
Abstract
The classic dogma of cerebral autoregulation is that cerebral blood flow is steadily maintained across a wide range of perfusion pressures. This has been challenged by recent studies suggesting little to no "autoregulatory plateau" in the relationship between cerebral blood flow and blood pressure (BP). Therefore, the mechanisms underlying the cerebral pressure-flow relationship still require further understanding. Here, we present a novel approach to examine dynamic cerebral autoregulation in conscious Wistar rats (n = 16) instrumented to measure BP and internal carotid blood flow (iCBF), as an indicator of cerebral blood flow. Transient reductions in BP were induced by occluding the vena cava via inflation of a chronically implanted intravascular silicone balloon. Falls in BP were paralleled by progressive decreases in iCBF, with no evidence of a steady-state plateau. No significant changes in internal carotid vascular resistance (iCVR) were observed. In contrast, intravenous infusions of the vasoactive drug sodium nitroprusside (SNP) produced a similar fall in BP but increases in iCBF and decreases in iCVR were observed. These data suggest a considerable confounding influence of vasodilatory drugs such as SNP on cerebrovascular tone in the rat, making them unsuitable to investigate cerebral autoregulation. We demonstrate that our technique of transient vena cava occlusion produced reliable and repeatable depressor responses, highlighting the potential for our approach to permit assessment of the dynamic cerebral pressure-flow relationship over time in conscious rats.NEW & NOTEWORTHY We present a novel technique to overcome the use of vasoactive agents when studying cerebrovascular dynamics in the conscious rat. Our method of vena cava occlusion to reduce BP was associated with decreased iCBF and no change in iCVR. In contrast, comparable BP falls with intravenous SNP increased iCBF and reduced iCVR. Thus, the dynamic cerebral pressure-flow relationship shows a narrower, less level autoregulatory plateau than conventionally thought. We confirm our method allows repeatable assessment of cerebrovascular dynamics in conscious rats.
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Affiliation(s)
- Debra Fong
- Manaaki Mānawa-The Centre for Heart Research, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Kelly Gradon
- Manaaki Mānawa-The Centre for Heart Research, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Carolyn J Barrett
- Manaaki Mānawa-The Centre for Heart Research, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Sarah-Jane Guild
- Manaaki Mānawa-The Centre for Heart Research, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Yu Chieh Tzeng
- Wellington Medical Technology Group, Centre for Translational Physiology, University of Otago, Wellington, New Zealand
| | - Julian F R Paton
- Manaaki Mānawa-The Centre for Heart Research, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Fiona D McBryde
- Manaaki Mānawa-The Centre for Heart Research, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
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20
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Dynamic cerebral autoregulation during early orthostatic exercise in patients with severe traumatic brain injury: Further exploratory analyses from a randomized clinical feasibility trial. J Clin Neurosci 2021; 92:39-44. [PMID: 34509259 DOI: 10.1016/j.jocn.2021.07.047] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 06/25/2021] [Accepted: 07/25/2021] [Indexed: 01/10/2023]
Abstract
In patients with severe traumatic brain injury, there is limited evidence of the clinical effect of early orthostatic exercise, although such exercise may strengthen systemic or cerebral hemodynamic responses to head-up tilt, thereby minimizing orthostatic intolerance. We measured dynamic cerebral autoregulation (dCA) and the occurrence of orthostatic intolerance after four weeks of regular orthostatic exercise by head-up tilt using a tilt table with integrated stepping using the ERIGO® tilt-table and comparing it to standard care. Thirty-four patients with severe traumatic brain injury admitted to a neurocritical care unit were included in this randomized clinical trial. Middle cerebral artery blood flow velocity (MCAv), non-invasive mean arterial pressure, heart rate and PaCO2 were recorded; dCA was measured by the non-invasive mean flow index (nMxa). Transition from the supine position to head-up tilt triggered a 10-16% decrease in MCAv and increased nMxa in both groups at all time points (P < 0.05), with no differences between groups. There was no difference in the number of episodes with orthostatic intolerance (5 vs 3; 1 vs 2; 1 vs 0) at baseline, two weeks and four weeks, respectively, and no association between changes in PaCO2-adjusted nMxa and the occurrence of orthostatic reactions (P = 0.35). Early orthostatic exercise does not affect dynamic cerebral autoregulation and does not protect against orthostatic intolerance in patients with severe traumatic brain injury. Trial registration: ClinicalTrials.gov identifier: NCT02924649. Registered on 3rd October 2016.
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21
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Ogoh S, Washio T, Stacey BS, Tsukamoto H, Iannetelli A, Owens TS, Calverley TA, Fall L, Marley CJ, Saito S, Watanabe H, Hashimoto T, Ando S, Miyamoto T, Bailey DM. Integrated respiratory chemoreflex-mediated regulation of cerebral blood flow in hypoxia: Implications for oxygen delivery and acute mountain sickness. Exp Physiol 2021; 106:1922-1938. [PMID: 34318560 DOI: 10.1113/ep089660] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 07/20/2021] [Indexed: 12/30/2022]
Abstract
NEW FINDINGS What is the central question of this study? To what extent do hypoxia-induced changes in the peripheral and central respiratory chemoreflex modulate anterior and posterior cerebral oxygen delivery, with corresponding implications for susceptibility to acute mountain sickness? What is the main finding and its importance? We provide evidence for site-specific regulation of cerebral blood flow in hypoxia that preserves oxygen delivery in the posterior but not the anterior cerebral circulation, with minimal contribution from the central respiratory chemoreflex. External carotid artery vasodilatation might prove to be an alternative haemodynamic risk factor that predisposes to acute mountain sickness. ABSTRACT The aim of the present study was to determine the extent to which hypoxia-induced changes in the peripheral and central respiratory chemoreflex modulate anterior and posterior cerebral blood flow (CBF) and oxygen delivery (CDO2 ), with corresponding implications for the pathophysiology of the neurological syndrome, acute mountain sickness (AMS). Eight healthy men were randomly assigned single blind to 7 h of passive exposure to both normoxia (21% O2 ) and hypoxia (12% O2 ). The peripheral and central respiratory chemoreflex, internal carotid artery, external carotid artery (ECA) and vertebral artery blood flow (duplex ultrasound) and AMS scores (questionnaires) were measured throughout. A reduction in internal carotid artery CDO2 was observed during hypoxia despite a compensatory elevation in perfusion. In contrast, vertebral artery and ECA CDO2 were preserved, and the former was attributable to a more marked increase in perfusion. Hypoxia was associated with progressive activation of the peripheral respiratory chemoreflex (P < 0.001), whereas the central respiratory chemoreflex remained unchanged (P > 0.05). Symptom severity in participants who developed clinical AMS was positively related to ECA blood flow (Lake Louise score, r = 0.546-0.709, P = 0.004-0.043; Environmental Symptoms Questionnaires-Cerebral symptoms score, r = 0.587-0.771, P = 0.001-0.027, n = 4). Collectively, these findings highlight the site-specific regulation of CBF in hypoxia that maintains CDO2 selectively in the posterior but not the anterior cerebral circulation, with minimal contribution from the central respiratory chemoreflex. Furthermore, ECA vasodilatation might represent a hitherto unexplored haemodynamic risk factor implicated in the pathophysiology of AMS.
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Affiliation(s)
- Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, Kawagoe, Saitama, Japan.,Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK
| | - Takuro Washio
- Department of Biomedical Engineering, Toyo University, Kawagoe, Saitama, Japan
| | - Benjamin S Stacey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK
| | - Hayato Tsukamoto
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK.,Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan
| | - Angelo Iannetelli
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK
| | - Thomas S Owens
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK
| | - Thomas A Calverley
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK
| | - Lewis Fall
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK
| | - Christopher J Marley
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK
| | - Shotaro Saito
- Department of Biomedical Engineering, Toyo University, Kawagoe, Saitama, Japan
| | - Hironori Watanabe
- Department of Biomedical Engineering, Toyo University, Kawagoe, Saitama, Japan
| | - Takeshi Hashimoto
- Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan
| | - Soichi Ando
- Graduate School of Informatics and Engineering, The University of Electro-Communications, Tokyo, Japan
| | | | - Damian M Bailey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK
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22
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Cerebral Autoregulation during Postural Change in Patients with Cervical Spinal Cord Injury-A Carotid Duplex Ultrasonography Study. Diagnostics (Basel) 2021; 11:diagnostics11081321. [PMID: 34441256 PMCID: PMC8393722 DOI: 10.3390/diagnostics11081321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Revised: 07/13/2021] [Accepted: 07/21/2021] [Indexed: 11/17/2022] Open
Abstract
Patients with a spinal cord injury (SCI) frequently experience sudden falls in blood pressure during postural change. Few studies have investigated whether the measurement of blood flow velocity within vessels can reflect brain perfusion during postural change. By performing carotid duplex ultrasonography (CDU), we investigated changes in cerebral blood flow (CBF) during postural changes in patients with a cervical SCI, determined the correlation of CBF change with presyncopal symptoms, and investigated factors affecting cerebral autoregulation. We reviewed the medical records of 100 patients with a cervical SCI who underwent CDU. The differences between the systolic blood pressure, diastolic blood pressure, and CBF volume in the supine posture and after 5 min at 50° tilt were evaluated. Presyncopal symptoms occurred when the blood flow volume of the internal carotid artery decreased by ≥21% after tilt. In the group that had orthostatic hypotension and severe CBF decrease during tilt, the body mass index and physical and functional scores were lower than in other groups, and the proportion of patients with a severe SCI was high. The higher the SCI severity and the lower the functional score, the higher the possibility of cerebral autoregulation failure. CBF should be assessed by conducting CDU in patients with a high-level SCI.
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23
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Lee BC, Tsai HH, Huang APH, Lo YL, Tsai LK, Chen YF, Wu WC. Arterial Spin Labeling Imaging Assessment of Cerebrovascular Reactivity in Hypertensive Small Vessel Disease. Front Neurol 2021; 12:640069. [PMID: 34276531 PMCID: PMC8278327 DOI: 10.3389/fneur.2021.640069] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 05/25/2021] [Indexed: 11/21/2022] Open
Abstract
Objective: Cerebrovascular reactivity (CVR) represents the phenomenon where cerebral vessels dilate or constrict in response to vasoactive stimuli. CVR impairment may contribute to brain injury due to cerebral small vessel disease (SVD). We aimed to determine the CVR in hypertensive intracerebral hemorrhage (ICH) and to identify its vascular dysfunction. Methods: A total of 21 patients with spontaneous hypertensive ICH (strictly deep or mixed deep and lobar hemorrhages, mean age 62.5 ± 11.3 years) and 10 control subjects (mean age 66.1 ± 6.0 years) were enrolled for CVR measurement at least 3 months after the symptomatic ICH event. Each participant underwent a brain MRI study, and CVR was calculated as the cerebral blood flow (CBF) reduction using arterial spin labeling (ASL) between baseline and 10 min after an intravenous dipyridamole injection (0.57 mg/kg). Traditional MRI markers for SVD were also evaluated, including cerebral microbleed, white matter hyperintensity, lacune, and MRI-visible enlarged perivascular space, which were used to determine the total small vessel disease score. Results: Compared to control subjects, hypertensive ICH patients showed reduced CVR in the basal ganglia (CBF reduction 22.4 ± 22.7% vs. 41.7 ± 18.3, p = 0.026), the frontal lobe (15.1 ± 11.9 vs. 26.6 ± 9.9, p = 0.013), and the temporal lobe (14.7 ± 11.1 vs. 26.2 ± 10.0, p = 0.010). These differences remained significant in multivariable models after adjusting for age and sex. Within ICH groups, the CBF reduction in the basal ganglia was significantly correlated with the total small vessel disease score (R = 0.58, p = 0.006), but not with individual MRI markers. Conclusion: Patients with advanced hypertensive SVD demonstrated impaired vasoconstriction after dipyridamole challenge in the basal ganglia and the frontal and temporal lobes. Our findings provide safe approaches for whole-brain CVR mapping in SVD and identify a potential physiological basis for vascular dysfunction in hypertensive SVD.
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Affiliation(s)
- Bo-Ching Lee
- Department of Medical Imaging, National Taiwan University Hospital, Taipei, Taiwan.,Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Hsin-Hsi Tsai
- Department of Neurology, National Taiwan University Hospital Bei-Hu Branch, Taipei, Taiwan.,Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan
| | - Abel Po-Hao Huang
- Division of Neurosurgery, Department of Surgery, National Taiwan University Hospital, Taipei, Taiwan
| | - Yen-Ling Lo
- Department of Neurology, National Taiwan University Hospital Bei-Hu Branch, Taipei, Taiwan
| | - Li-Kai Tsai
- Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan
| | - Ya-Fang Chen
- Department of Medical Imaging, National Taiwan University Hospital, Taipei, Taiwan
| | - Wen-Chau Wu
- Institute of Medical Device and Imaging, National Taiwan University College of Medicine, Taipei, Taiwan
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24
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Perry BG, Lucas SJE. The Acute Cardiorespiratory and Cerebrovascular Response to Resistance Exercise. SPORTS MEDICINE-OPEN 2021; 7:36. [PMID: 34046740 PMCID: PMC8160070 DOI: 10.1186/s40798-021-00314-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 03/07/2021] [Indexed: 12/18/2022]
Abstract
Resistance exercise (RE) is a popular modality for the general population and athletes alike, due to the numerous benefits of regular participation. The acute response to dynamic RE is characterised by temporary and bidirectional physiological extremes, not typically seen in continuous aerobic exercise (e.g. cycling) and headlined by phasic perturbations in blood pressure that challenge cerebral blood flow (CBF) regulation. Cerebral autoregulation has been heavily scrutinised over the last decade with new data challenging the effectiveness of this intrinsic flow regulating mechanism, particularly to abrupt changes in blood pressure over the course of seconds (i.e. dynamic cerebral autoregulation), like those observed during RE. Acutely, RE can challenge CBF regulation, resulting in adverse responses (e.g. syncope). Compared with aerobic exercise, RE is relatively understudied, particularly high-intensity dynamic RE with a concurrent Valsalva manoeuvre (VM). However, the VM alone challenges CBF regulation and generates additional complexity when trying to dissociate the mechanisms underpinning the circulatory response to RE. Given the disparate circulatory response between aerobic and RE, primarily the blood pressure profiles, regulation of CBF is ostensibly different. In this review, we summarise current literature and highlight the acute physiological responses to RE, with a focus on the cerebral circulation.
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Affiliation(s)
- Blake G Perry
- School of Health Sciences, Massey University, Wellington, New Zealand.
| | - Samuel J E Lucas
- School of Sport, Exercise and Rehabilitation Sciences & Centre for Human Brain Health, College of Life and Environmental Sciences, University of Birmingham, Birmingham, UK
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25
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Friend AT, Rogan M, Rossetti GMK, Lawley JS, Mullins PG, Sandoo A, Macdonald JH, Oliver SJ. Bilateral regional extracranial blood flow regulation to hypoxia and unilateral duplex ultrasound measurement error. Exp Physiol 2021; 106:1535-1548. [PMID: 33866627 DOI: 10.1113/ep089196] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 04/14/2021] [Indexed: 02/05/2023]
Abstract
NEW FINDINGS What is the central question of this study? Is blood flow regulation to hypoxia different between the internal carotid arteries (ICAs) and vertebral arteries (VAs), and what is the measurement error in unilateral extracranial artery assessments compared to bilateral? What is the main finding and its importance? ICA and VA blood flow regulation to hypoxia is comparable when factoring for vessel type and vessel side. Compared to bilateral assessment, vessels assessed unilaterally had individual measurement errors of up to 37%. Assessing the vessel with the larger resting blood flow, not the left or right vessel, reduces unilateral measurement error. ABSTRACT Whether blood flow regulation to hypoxia is similar between left and right internal carotid arteries (ICAs) and vertebral arteries (VAs) is unclear. Extracranial blood flow is regularly calculated by doubling a unilateral assessment; however, lateral artery differences may lead to measurement error. This study aimed to determine extracranial blood flow regulation to hypoxia when factoring for vessel type (ICAs or VAs) and vessel side (left or right) effects, and to investigate unilateral assessment measurement error compared to bilateral assessment. In a repeated-measures crossover design, extracranial arteries of 44 participants were assessed bilaterally by duplex ultrasound during 90 min of normoxic and poikilocapnic hypoxic (12.0% fraction of inspired oxygen) conditions. Linear mixed model analyses revealed no Condition × Vessel Type × Vessel Side interaction for blood flow, vessel diameter and flow velocity (all P > 0.05) indicating left and right ICA and VA blood flow regulation to hypoxia was similar. Bilateral hypoxic reactivity was comparable (ICAs, 1.4 (1.0) vs. VAs, 1.7 (1.1) Δ%·Δ S p O 2 -1 ; P = 0.12). Compared to bilateral assessment, unilateral mean measurement error of the relative blood flow response to hypoxia was up to 5%, but individual errors reached 37% and were greatest in ICAs and VAs with the smaller resting blood flow due to a ratio-scaling problem. In conclusion, left and right ICA and VA regulation to hypoxia is comparable when factoring for vessel type and vessel side. Assessing the ICA and VA vessels with the larger resting blood flow, not the left or right vessel, reduces unilateral measurement error.
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Affiliation(s)
- Alexander T Friend
- Extremes Research Group, School of Sport, Health and Exercise Sciences, College of Human Sciences, Bangor University, Bangor, UK
| | - Matthew Rogan
- Bangor Imaging Unit, School of Psychology, College of Human Sciences, Bangor University, Bangor, UK
| | - Gabriella M K Rossetti
- Extremes Research Group, School of Sport, Health and Exercise Sciences, College of Human Sciences, Bangor University, Bangor, UK.,Centre for Integrative Neuroscience and Neurodynamics, School of Psychology and Clinical Language Sciences, University of Reading, Reading, UK
| | - Justin S Lawley
- Department of Sport Science, Division of Physiology, University of Innsbruck, Innsbruck, Austria
| | - Paul G Mullins
- Bangor Imaging Unit, School of Psychology, College of Human Sciences, Bangor University, Bangor, UK
| | - Aamer Sandoo
- Extremes Research Group, School of Sport, Health and Exercise Sciences, College of Human Sciences, Bangor University, Bangor, UK
| | - Jamie H Macdonald
- Extremes Research Group, School of Sport, Health and Exercise Sciences, College of Human Sciences, Bangor University, Bangor, UK
| | - Samuel J Oliver
- Extremes Research Group, School of Sport, Health and Exercise Sciences, College of Human Sciences, Bangor University, Bangor, UK
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26
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Labrecque L, Drapeau A, Rahimaly K, Imhoff S, Brassard P. Dynamic cerebral autoregulation and cerebrovascular carbon dioxide reactivity in middle and posterior cerebral arteries in young endurance-trained women. J Appl Physiol (1985) 2021; 130:1724-1735. [PMID: 33955257 DOI: 10.1152/japplphysiol.00963.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The integrated responses regulating cerebral blood flow are understudied in women, particularly in relation to potential regional differences. In this study, we compared dynamic cerebral autoregulation (dCA) and cerebrovascular reactivity to carbon dioxide (CVRco2) in the middle (MCA) and posterior cerebral arteries (PCA) in 11 young endurance-trained women (age, 25 ± 4 yr; maximal oxygen uptake, 48.1 ± 4.1 mL·kg-1·min-1). dCA was characterized using a multimodal approach including a sit-to-stand and a transfer function analysis (TFA) of forced blood pressure oscillations (repeated squat-stands executed at 0.05 Hz and 0.10 Hz). The hyperoxic rebreathing test was utilized to characterize CVRco2. Upon standing, the percent reduction in blood velocity per percent reduction in mean arterial pressure during initial orthostatic stress (0-15 s after sit-to-stand), the onset of the regulatory response, and the rate of regulation did not differ between MCA and PCA (all P > 0.05). There was an ANOVA effect of anatomical location for TFA gain (P < 0.001) and a frequency effect for TFA phase (P < 0.001). However, normalized gain was not different between arteries (P = 0.18). Absolute CVRco2 was not different between MCA and PCA (1.55 ± 0.81 vs. 1.30 ± 0.49 cm·s-1/Torr, P = 0.26). Relative CVRco2 was 39% lower in the MCA (2.16 ± 1.02 vs. 3.00 ± 1.09%/Torr, P < 0.01). These findings indicate that the cerebral pressure-flow relationship appears to be similar between the MCA and the PCA in young endurance-trained women. The absence of regional differences in absolute CVRco2 could be women specific, although a direct comparison with a group of men will be necessary to address that issue.NEW & NOTEWORTHY Herein, we describe responses from two major mechanisms regulating cerebral blood flow with a special attention on regional differences in young endurance-trained women. The novel findings are that dynamic cerebral autoregulation and absolute cerebrovascular reactivity to carbon dioxide appear similar between the middle and posterior cerebral arteries of these young women.
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Affiliation(s)
- Lawrence Labrecque
- Department of Kinesiology, Faculty of Medicine, Université Laval, Quebec City, Québec, Canada.,Research Center of the Institut Universitaire de Cardiologie et de Pneumologie de Québec, Quebec City, Québec, Canada
| | - Audrey Drapeau
- Department of Kinesiology, Faculty of Medicine, Université Laval, Quebec City, Québec, Canada.,Research Center of the Institut Universitaire de Cardiologie et de Pneumologie de Québec, Quebec City, Québec, Canada
| | - Kevan Rahimaly
- Department of Kinesiology, Faculty of Medicine, Université Laval, Quebec City, Québec, Canada.,Research Center of the Institut Universitaire de Cardiologie et de Pneumologie de Québec, Quebec City, Québec, Canada
| | - Sarah Imhoff
- Department of Kinesiology, Faculty of Medicine, Université Laval, Quebec City, Québec, Canada.,Research Center of the Institut Universitaire de Cardiologie et de Pneumologie de Québec, Quebec City, Québec, Canada
| | - Patrice Brassard
- Department of Kinesiology, Faculty of Medicine, Université Laval, Quebec City, Québec, Canada.,Research Center of the Institut Universitaire de Cardiologie et de Pneumologie de Québec, Quebec City, Québec, Canada
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27
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Mohammadyari P, Gadda G, Taibi A. Modelling physiology of haemodynamic adaptation in short-term microgravity exposure and orthostatic stress on Earth. Sci Rep 2021; 11:4672. [PMID: 33633331 PMCID: PMC7907254 DOI: 10.1038/s41598-021-84197-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 02/08/2021] [Indexed: 11/09/2022] Open
Abstract
Cardiovascular haemodynamics alters during posture changes and exposure to microgravity. Vascular auto-remodelling observed in subjects living in space environment causes them orthostatic intolerance when they return on Earth. In this study we modelled the human haemodynamics with focus on head and neck exposed to different hydrostatic pressures in supine, upright (head-up tilt), head-down tilt position, and microgravity environment by using a well-developed 1D-0D haemodynamic model. The model consists of two parts that simulates the arterial (1D) and brain-venous (0D) vascular tree. The cardiovascular system is built as a network of hydraulic resistances and capacitances to properly model physiological parameters like total peripheral resistance, and to calculate vascular pressure and the related flow rate at any branch of the tree. The model calculated 30.0 mmHg (30%), 7.1 mmHg (78%), 1.7 mmHg (38%) reduction in mean blood pressure, intracranial pressure and central venous pressure after posture change from supine to upright, respectively. The modelled brain drainage outflow percentage from internal jugular veins is 67% and 26% for supine and upright posture, while for head-down tilt and microgravity is 65% and 72%, respectively. The model confirmed the role of peripheral veins in regional blood redistribution during posture change from supine to upright and microgravity environment as hypothesized in literature. The model is able to reproduce the known haemodynamic effects of hydraulic pressure change and weightlessness. It also provides a virtual laboratory to examine the consequence of a wide range of orthostatic stresses on human haemodynamics.
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Affiliation(s)
- Parvin Mohammadyari
- Department of Physics and Earth Sciences, University of Ferrara, 44122, Ferrara, Italy
| | - Giacomo Gadda
- National Institute for Nuclear Physics (INFN), Section of Ferrara, 44122, Ferrara, Italy.
| | - Angelo Taibi
- Department of Physics and Earth Sciences, University of Ferrara, 44122, Ferrara, Italy
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28
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Comparisons of the Nonlinear Relationship of Cerebral Blood Flow Response and Cerebral Vasomotor Reactivity to Carbon Dioxide under Hyperventilation between Postural Orthostatic Tachycardia Syndrome Patients and Healthy Subjects. J Clin Med 2020; 9:jcm9124088. [PMID: 33352894 PMCID: PMC7767239 DOI: 10.3390/jcm9124088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 12/16/2020] [Accepted: 12/16/2020] [Indexed: 11/29/2022] Open
Abstract
Postural orthostatic tachycardia syndrome (POTS) typically occurs in youths, and early accurate POTS diagnosis is challenging. A recent hypothesis suggests that upright cognitive impairment in POTS occurs because reduced cerebral blood flow velocity (CBFV) and cerebrovascular response to carbon dioxide (CO2) are nonlinear during transient changes in end-tidal CO2 (PETCO2). This novel study aimed to reveal the interaction between cerebral autoregulation and ventilatory control in POTS patients by using tilt table and hyperventilation to alter the CO2 tension between 10 and 30 mmHg. The cerebral blood flow velocity (CBFV), partial pressure of end-tidal carbon dioxide (PETCO2), and other cardiopulmonary signals were recorded for POTS patients and two healthy groups including those aged >45 years (Healthy-Elder) and aged <45 years (Healthy-Youth) throughout the experiment. Two nonlinear regression functions, Models I and II, were applied to evaluate their CBFV-PETCO2 relationship and cerebral vasomotor reactivity (CVMR). Among the estimated parameters, the curve-fitting Model I for CBFV and CVMR responses to CO2 for POTS patients demonstrated an observable dissimilarity in CBFVmax (p = 0.011), mid-PETCO2 (p = 0.013), and PETCO2 range (p = 0.023) compared with those of Healthy-Youth and in CBFVmax (p = 0.015) and CVMRmax compared with those of Healthy-Elder. With curve-fitting Model II for POTS patients, the fit parameters of curvilinear (p = 0.036) and PETCO2 level (p = 0.033) displayed significant difference in comparison with Healthy-Youth parameters; range of change (p = 0.042), PETCO2 level, and CBFVmax also displayed a significant difference in comparison with Healthy-Elder parameters. The results of this study contribute toward developing an early accurate diagnosis of impaired CBFV responses to CO2 for POTS patients.
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29
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Lee SMC, Martin DS, Miller CA, Scott JM, Laurie SS, Macias BR, Mercaldo ND, Ploutz-Snyder L, Stenger MB. Venous and Arterial Responses to Partial Gravity. Front Physiol 2020; 11:863. [PMID: 32848835 PMCID: PMC7399573 DOI: 10.3389/fphys.2020.00863] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 06/26/2020] [Indexed: 01/25/2023] Open
Abstract
Introduction: Chronic exposure to the weightlessness-induced cephalad fluid shift is hypothesized to be a primary contributor to the development of spaceflight-associated neuro-ocular syndrome (SANS) and may be associated with an increased risk of venous thrombosis in the jugular vein. This study characterized the relationship between gravitational level (Gz-level) and acute vascular changes. Methods: Internal jugular vein (IJV) cross-sectional area, inferior vena cava (IVC) diameter, and common carotid artery (CCA) flow were measured using ultrasound in nine subjects (5F, 4M) while seated when exposed to 1.00-Gz, 0.75-Gz, 0.50-Gz, and 0.25-Gz during parabolic flight and while supine before flight (0-G analog). Additionally, IJV flow patterns were characterized. Results: IJV cross-sectional area progressively increased from 12 (95% CI: 9–16) mm2 during 1.00-Gz seated to 24 (13–35), 34 (21–46), 68 (40–97), and 103 (75–131) mm2 during 0.75-Gz, 0.50-Gz, and 0.25-Gz seated and 1.00-Gz supine, respectively. Also, IJV flow pattern shifted from the continuous forward flow observed during 1.00-Gz and 0.75-Gz seated to pulsatile flow during 0.50-Gz seated, 0.25-Gz seated, and 1.00-Gz supine. In contrast, we were unable to detect differences in IVC diameter measured during 1.00-G seated and any level of partial gravity or during 1.00-Gz supine. CCA blood flow during 1.00-G seated was significantly less than 0.75-Gz and 1.00-Gz supine but differences were not detected at partial gravity levels 0.50-Gz and 0.25-Gz. Conclusions: Acute exposure to decreasing Gz-levels is associated with an expansion of the IJV and flow patterns that become similar to those observed in supine subjects and in astronauts during spaceflight. These data suggest that Gz-levels greater than 0.50-Gz may be required to reduce the weightlessness-induced headward fluid shift that may contribute to the risks of SANS and venous thrombosis during spaceflight.
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Affiliation(s)
| | | | | | - Jessica M Scott
- Memorial Sloan Kettering Cancer Center, New York, NY, United States
| | | | | | | | - Lori Ploutz-Snyder
- School of Kinesiology, University of Michigan, Ann Arbor, MI, United States
| | - Michael B Stenger
- Lyndon B. Johnson Space Center, National Aeronautics and Space Administration, Houston, TX, United States
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30
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Brognara F, Felippe ISA, Salgado HC, Paton JFR. Autonomic innervation of the carotid body as a determinant of its sensitivity: implications for cardiovascular physiology and pathology. Cardiovasc Res 2020; 117:1015-1032. [PMID: 32832979 DOI: 10.1093/cvr/cvaa250] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 07/01/2020] [Accepted: 08/18/2020] [Indexed: 12/14/2022] Open
Abstract
The motivation for this review comes from the emerging complexity of the autonomic innervation of the carotid body (CB) and its putative role in regulating chemoreceptor sensitivity. With the carotid bodies as a potential therapeutic target for numerous cardiorespiratory and metabolic diseases, an understanding of the neural control of its circulation is most relevant. Since nerve fibres track blood vessels and receive autonomic innervation, we initiate our review by describing the origins of arterial feed to the CB and its unique vascular architecture and blood flow. Arterial feed(s) vary amongst species and, unequivocally, the arterial blood supply is relatively high to this organ. The vasculature appears to form separate circuits inside the CB with one having arterial venous anastomoses. Both sympathetic and parasympathetic nerves are present with postganglionic neurons located within the CB or close to it in the form of paraganglia. Their role in arterial vascular resistance control is described as is how CB blood flow relates to carotid sinus afferent activity. We discuss non-vascular targets of autonomic nerves, their possible role in controlling glomus cell activity, and how certain transmitters may relate to function. We propose that the autonomic nerves sub-serving the CB provide a rapid mechanism to tune the gain of peripheral chemoreflex sensitivity based on alterations in blood flow and oxygen delivery, and might provide future therapeutic targets. However, there remain a number of unknowns regarding these mechanisms that require further research that is discussed.
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Affiliation(s)
- Fernanda Brognara
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton Auckland 1023, New Zealand.,Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Igor S A Felippe
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton Auckland 1023, New Zealand
| | - Helio C Salgado
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Julian F R Paton
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton Auckland 1023, New Zealand
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31
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Ogoh S, Washio T, Paton JFR, Fisher JP, Petersen LG. Gravitational effects on intracranial pressure and blood flow regulation in young men: a potential shunting role for the external carotid artery. J Appl Physiol (1985) 2020; 129:901-908. [PMID: 32816640 DOI: 10.1152/japplphysiol.00369.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
We sought to determine whether gravity-induced changes in intracranial pressure influence cerebral blood flow regulation. Accordingly, nine young healthy men were studied while supine (0°) and during mild changes in hydrostatic pressure induced by head-up tilt at +20° and +10° (HUT+20 and HUT+10) and head-down tilt at -20° and -10° (HDT-20, HDT-10). Blood flows were measured in the internal and external carotid and vertebral arteries (ICA, ECA, and VA). Intraocular pressure (IOP) was measured as an indicator of hydrostatic changes in intracranial pressure. A posture change from HUT+20 to HDT-20 increased IOP by +5.1 ± 1.9 mmHg (P < 0.001) and ECA blood flow (from 61.7 ± 26.1 to 87.6 ± 46.4 mL/min, P = 0.004) but did not affect ICA (P = 0.528) or VA (P = 0.101) blood flow. The increase in ECA flow correlated with the tilt angle and resultant changes in intracranial pressures (by IOP), thus indicating a passive hydrostatic gravitational dependence (r = 0.371, P = 0.012). On the contrary, ICA flow remained constant and thus well protected against moderate orthostatic stress. When ICA flow was corrected for the gravitational changes in intracranial pressures (by IOP), it demonstrated the same magnitude of gravitational dependence as ECA. These findings suggest that passive hydrostatic increases in intracranial pressure outbalance the concurrent increase in arterial feeding pressure to the brain and thus prevent cerebral hyperperfusion during HDT. The mechanism for maintaining constant cerebral flow was by increased ECA flow, thus supporting the role of these vascular beds as a shunting pathway.NEW & NOTEWORTHY We investigated whether gravity-induced changes in intracranial pressure influence cerebral blood flow regulation in young men. We recorded extra- and intracerebral blood flow during changes in posture, and data indicate that the external carotid artery may serve as an overflow pathway to prevent cerebral hyperperfusion during increases in cerebral arterial blood pressure.
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Affiliation(s)
- Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan
| | - Takuro Washio
- Department of Biomedical Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan.,Japan Society for the Promotion of Science, Tokyo, Japan
| | - Julian F R Paton
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - James P Fisher
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Lonnie G Petersen
- Department of Biomedical Science, Faculty of Health Science, University of Copenhagen, Copenhagen, Denmark.,Department of Radiology, University of California, San Diego, California.,Department of Mechanical and Aerospace Engineering, University of California, San Diego, California
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Bailey DM, Lanéelle D, Trihan JE, Marchi N, Stacey BS, Tamiya K, Washio T, Tuaillon E, Hirtz C, Lehmann S, Ogoh S, Normand H. Gravitational Transitions Increase Posterior Cerebral Perfusion and Systemic Oxidative-nitrosative Stress: Implications for Neurovascular Unit Integrity. Neuroscience 2020; 441:142-160. [PMID: 32502571 DOI: 10.1016/j.neuroscience.2020.05.048] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Revised: 05/22/2020] [Accepted: 05/26/2020] [Indexed: 12/12/2022]
Abstract
The present study examined if repeated bouts of micro- and hypergravity during parabolic flight (PF) alter structural integrity of the neurovascular unit (NVU) subsequent to free radical-mediated changes in regional cerebral perfusion. Six participants (5♂, 1♀) aged 29 ± 11 years were examined before, during and after a 3 h PF and compared to six sex and age-matched (27 ± 6 years) normogravity controls. Blood flow was measured in the anterior (middle cerebral artery, MCA; internal carotid artery, ICA) and posterior (vertebral artery, VA) circulation (duplex ultrasound) in-flight over the course of 15 parabolas. Venous blood was assayed for free radicals (electron paramagnetic resonance spectroscopy), nitric oxide (NO, ozone-based chemiluminescence) and NVU integrity (chemiluminescence/ELISA) in normogravity before and after exposure to 31 parabolas. While MCA velocity did not change (P > 0.05), a selective increase in VA flow was observed during the most marked gravitational transition from micro- to hypergravity (P < 0.05). Increased oxidative-nitrosative stress defined by a free radical-mediated reduction in NO and elevations in glio-vascular GFAP and S100ß were observed after PF (P < 0.05), the latter proportional to the increase in VA flow (r = 0.908, P < 0.05). In contrast, biomarkers of neuronal-axonal damage (neuron-specific enolase, neurofilament light-chain, ubiquitin carboxy-terminal hydrolase L1 and tau) did not change (P > 0.05). Collectively, these findings suggest that the cumulative effects of repeated gravitational transitions may promote minor blood-brain barrier disruption, potentially related to the combined effects of haemodynamic (posterior cerebral hyperperfusion) and molecular (systemic oxidative-nitrosative) stress.
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Affiliation(s)
- Damian M Bailey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Glamorgan, UK.
| | - Damien Lanéelle
- Service de Médecine Vasculaire, Centre Hospitalo-Universitaire, Caen, France; UNICAEN, INSERM, COMETE, GIP CYCERON, Normandie University, Caen, France
| | - Jean-Eudes Trihan
- Service de Médecine Vasculaire, Centre Hospitalier Universitaire de Poitiers, Poitiers, France
| | - Nicola Marchi
- UMR, Laboratory of Cerebrovascular and Glia Research, Department of Neuroscience, Institute of Functional Genomics (CNRS Unit Mixte de Recherche 5203; INSERM U1191), University of Montpellier, France
| | - Benjamin S Stacey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Glamorgan, UK
| | - Kazuki Tamiya
- Department of Biomedical Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan
| | - Takuro Washio
- Department of Biomedical Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan
| | - Edouard Tuaillon
- Unit Mixte de Recherche, INSERM l'Etablissement Français du Sang, University of Montpellier 1, Montpellier, France
| | - Christophe Hirtz
- LBPC-PPC, University of Montpellier, Institute of Regenerative Medicine-Biotherapy IRMB, Centre Hospitalier Universitaire de Montpellier, INSERM, Montpellier, France
| | - Sylvain Lehmann
- LBPC-PPC, University of Montpellier, Institute of Regenerative Medicine-Biotherapy IRMB, Centre Hospitalier Universitaire de Montpellier, INSERM, Montpellier, France
| | - Shigehiko Ogoh
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Glamorgan, UK; Department of Biomedical Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan
| | - Hervé Normand
- UNICAEN, INSERM, COMETE, GIP CYCERON, Normandie University, Caen, France; UNICAEN, COMETE, Caen, France; INSERM, U 1075 COMETE, Caen, France; Department of Clinical Physiology, Centre Hospitalier Universitaire de Caen, Caen, France
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Shibasaki M, Sato K, Hirasawa A, Sadamoto T, Crandall CG, Ogoh S. An assessment of hypercapnia-induced elevations in regional cerebral perfusion during combined orthostatic and heat stresses. J Physiol Sci 2020; 70:25. [PMID: 32366213 PMCID: PMC8006159 DOI: 10.1186/s12576-020-00751-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 04/23/2020] [Indexed: 11/10/2022]
Abstract
We investigated that the effects of hypercapnia-induced elevations in cerebral perfusion during a heat stress on global cerebrovascular responses to an orthostatic challenge. Seven volunteers completed a progressive lower-body negative pressure (LBNP) challenge to presyncope during heat stress, with or without breathing a hypercapnic gas mixture. Administration of the hypercapnic gas mixture increased the partial pressure of end-tidal CO2 greater than pre-heat stress alone, and increased both internal carotid artery (ICA) and vertebral artery (VA) blood flows (P < 0.05). During LBNP, both ICA and VA blood flows with the hypercapnic gas mixture remained elevated relative to the control trial (P < 0.05). However, at the end of LBNP due to pre-syncopal symptoms, both ICA and VA blood flows decreased to similar levels between trials. These findings suggest that hypercapnia-induced cerebral vasodilation is insufficient to maintain cerebral perfusion at the end of LBNP due to pre-syncope in either the anterior or posterior vascular beds.
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Affiliation(s)
- Manabu Shibasaki
- Department of Health Sciences, Faculty of Human Life and Environment, Nara Women's University, Kitauoya-Nishi Machi, Nara, 630-8506, Japan.
| | - Kohei Sato
- Department of Health and Physical Education, Tokyo Gakugei University, Tokyo, Japan
| | - Ai Hirasawa
- Department of Health and Welfare, Kyorin University, Tokyo, Japan
| | - Tomoko Sadamoto
- Research Institute of Physical Fitness, Japan Women's College of Physical Education, Tokyo, Japan
| | - Craig G Crandall
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, USA.,Department of Internal Medicine, University of Texas, Southwestern Medical Center, Dallas, USA
| | - Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, Saitama, Japan
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Internal carotid artery blood flow is enhanced by elevating blood pressure during combined propofol-remifentanil and thoracic epidural anaesthesia. Eur J Anaesthesiol 2020; 37:482-490. [DOI: 10.1097/eja.0000000000001189] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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35
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Favre ME, Lim V, Falvo MJ, Serrador JM. Cerebrovascular reactivity and cerebral autoregulation are improved in the supine posture compared to upright in healthy men and women. PLoS One 2020; 15:e0229049. [PMID: 32119678 PMCID: PMC7051088 DOI: 10.1371/journal.pone.0229049] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 01/28/2020] [Indexed: 12/04/2022] Open
Abstract
Cerebrovascular reactivity and cerebral autoregulation are two major mechanisms that regulate cerebral blood flow. Both mechanisms are typically assessed in either supine or seated postures, but the effects of body position and sex differences remain unclear. This study examined the effects of body posture (supine vs. seated vs. standing) on cerebrovascular reactivity during hyper and hypocapnia and on cerebral autoregulation during spontaneous and slow-paced breathing in healthy men and women using transcranial Doppler ultrasonography of the middle cerebral artery. Results indicated significantly improved cerebrovascular reactivity in the supine compared with seated and standing postures (supine = 3.45±0.67, seated = 2.72±0.53, standing = 2.91±0.62%/mmHg, P<0.0167). Similarly, cerebral autoregulatory measures showed significant improvement in the supine posture during slow-paced breathing. Transfer function measures of gain significantly decreased and phase significantly increased in the supine posture compared with seated and standing postures (gain: supine = 1.98±0.56, seated = 2.37±0.53, standing = 2.36±0.71%/mmHg; phase: supine = 59.3±21.7, seated = 39.8±12.5, standing = 36.5±9.7°; all P<0.0167). In contrast, body posture had no effect on cerebral autoregulatory measures during spontaneous breathing. Men and women had similar cerebrovascular reactivity and similar cerebral autoregulation during both spontaneous and slow-paced breathing. These data highlight the importance of making comparisons within the same body position to ensure there is not a confounding effect of posture.
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Affiliation(s)
- Michelle E. Favre
- Department of Pharmacology, Physiology and Neuroscience, Rutgers Biomedical and Health Sciences, Newark, New Jersey, United States of America
| | - Valerie Lim
- Department of Pharmacology, Physiology and Neuroscience, Rutgers Biomedical and Health Sciences, Newark, New Jersey, United States of America
| | - Michael J. Falvo
- Department of Pharmacology, Physiology and Neuroscience, Rutgers Biomedical and Health Sciences, Newark, New Jersey, United States of America
- Department of Physical Medicine and Rehabilitation, Rutgers Biomedical and Health Sciences, Newark, New Jersey, United States of America
- Department of Veterans Affairs, War Related Illness and Injury Study Center, East Orange, New Jersey, United States of America
| | - Jorge M. Serrador
- Department of Pharmacology, Physiology and Neuroscience, Rutgers Biomedical and Health Sciences, Newark, New Jersey, United States of America
- Department of Cardiovascular Electronics, National University of Ireland Galway, Galway, Ireland
- * E-mail:
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UBC-Nepal expedition: dynamic cerebral autoregulation is attenuated in lowlanders upon ascent to 5050 m. Eur J Appl Physiol 2020; 120:675-686. [DOI: 10.1007/s00421-020-04307-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 01/18/2020] [Indexed: 12/14/2022]
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Washio T, Watanabe H, Ogoh S. Dynamic cerebral autoregulation in anterior and posterior cerebral circulation during cold pressor test. J Physiol Sci 2020; 70:1. [PMID: 32039699 PMCID: PMC6987085 DOI: 10.1186/s12576-020-00732-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 01/22/2020] [Indexed: 12/26/2022]
Abstract
We hypothesized that cerebral blood flow (CBF) regulation in the posterior circulation differs from that of the anterior circulation during a cold pressor test (CPT) and is accompanied by elevations in arterial blood pressure (ABP) and sympathetic nervous activity (SNA). To test this, dynamic cerebral autoregulation (dCA) in the middle and posterior cerebral arteries (MCA and PCA) were measured at three different conditions: control, early phase of the CPT, and the late phase of the CPT. The dCA was examined using a thigh cuff occlusion and release technique. The MCA and PCA blood velocities were unchanged at CPT compared with the control conditions despite an elevation in the ABP. The dCA in both the MCA and PCA remained unaltered at CPT. These findings suggest that CPT-induced elevations in the ABP and SNA did not cause changes in the CBF regulation in the posterior circulation compared with the anterior circulation.
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Affiliation(s)
- Takuro Washio
- Department of Biomedical Engineering, Toyo University, 2100 Kujirai, Kawagoe-shi, Saitama, 350-8585, Japan.,Research Fellow of Japan Society for the Promotion of Science, Tokyo, Japan
| | - Hironori Watanabe
- Department of Biomedical Engineering, Toyo University, 2100 Kujirai, Kawagoe-shi, Saitama, 350-8585, Japan
| | - Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, 2100 Kujirai, Kawagoe-shi, Saitama, 350-8585, Japan.
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Cerebrovascular haemodynamics during isometric resistance exercise with and without the Valsalva manoeuvre. Eur J Appl Physiol 2020; 120:467-479. [PMID: 31912226 DOI: 10.1007/s00421-019-04291-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Accepted: 12/20/2019] [Indexed: 12/30/2022]
Abstract
PURPOSE To examine the interactive effects of VM and isometric resistance exercise on cerebral haemodynamics. METHODS Eleven healthy participants (mean ± SD 28 ± 9 years; 2 females) completed 20-s bilateral isometric leg extension at 50% of maximal voluntary contraction with continued ventilation (RE), a 20-s VM at mouth pressure of 40 mmHg (VM), and a combination (RE + VM), in randomised order. Mean beat-to-beat blood velocity in the posterior (PCAvmean) and middle cerebral arteries (MCAvmean), vertebral artery blood flow, end-tidal partial pressure of CO2 and mean arterial pressure (MAP) were measured. RE data were time aligned to RE + VM and analysed according to standard VM phases. RESULTS Interaction effects (VM phase × condition) were observed for MCAvmean, PCAvmean, vertebral artery blood flow and MAP (all ≤ 0.010). Phase I MCAvmean was greatest for RE [88 ± 19, vs. 71 ± 11 and 78 ± 12 cm s-1 for VM (P = 0.008) and RE + VM (P = 0.021), respectively]. Greater increases in MCAvmean than PCAvmean occurred in phase I of RE only (24 ± 15% vs. 16 ± 16%, post hoc P = 0.044). In phase IIb, MAP was lower in RE than RE + VM (115 ± 15 vs. 138 ± 21 mmHg, P = 0.004), but did not reduce MCAvmean (78 ± 8 vs. 79 ± 9 cm s-1, P = 0.579) or PCAvmean (45 ± 11 vs .46 ± 11 cm s-1, P = 0.617). Phase IIb MCAvmean and PCAvmean was lowest in VM (66 ± 6 and 39 ± 8 cm s-1, respectively, all P < 0.001), whereas in Phase IV, MCAvmean, PCAvmean and MAP were greater in VM than in RE and RE + VM (all P < 0.020). CONCLUSION RE and RE + VM produce similar cerebrovascular responses despite different MAP profiles. However, the VM produced the greatest cerebrovascular challenge afterward.
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Ogoh S, Sato K, Abreu S, Denise P, Normand H. Arterial and venous cerebral blood flow responses to long‐term head‐down bed rest in male volunteers. Exp Physiol 2019; 105:44-52. [DOI: 10.1113/ep088057] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 11/04/2019] [Indexed: 12/17/2022]
Affiliation(s)
- Shigehiko Ogoh
- Department of Biomedical Engineering Toyo University Kawagoe‐Shi Saitama Japan
| | - Kohei Sato
- Tokyo Gakugei University Koganei Tokyo Japan
| | - Steven Abreu
- Normandie Université, Unicaen; Inserm Comete GIP Cyceron Chu Caen France
| | - Pierre Denise
- Normandie Université, Unicaen; Inserm Comete GIP Cyceron Chu Caen France
| | - Hervé Normand
- Normandie Université, Unicaen; Inserm Comete GIP Cyceron Chu Caen France
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40
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Au JS, Yiu BYS, So H, Chee AJY, Greaves DK, Hughson RL, Yu ACH. Ultrasound vector projectile imaging for detection of altered carotid bifurcation hemodynamics during reductions in cardiac output. Med Phys 2019; 47:431-440. [PMID: 31693196 DOI: 10.1002/mp.13905] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Revised: 09/13/2019] [Accepted: 10/30/2019] [Indexed: 11/08/2022] Open
Abstract
PURPOSE Complex blood flow is commonly observed in the carotid bifurcation, although the factors that regulate these patterns beyond arterial geometry are unknown. The emergence of high-frame-rate ultrasound vector flow imaging allows for noninvasive, time-resolved analysis of complex hemodynamic behavior in humans, and it can potentially help researchers understand which physiological stressors can alter carotid bifurcation hemodynamics in vivo. Here, we seek to pursue the first use of vector projectile imaging (VPI), a dynamic form of vector flow imaging, to analyze the regulation of carotid bifurcation hemodynamics during experimental reductions in cardiac output induced via a physiological stressor called lower body negative pressure (LBNP). METHODS Seven healthy adults (age: 27 ± 4 yr, 4 men) underwent LBNP at -45 mmHg to simulate a postural hemodynamic response in a controlled environment. Using a research-grade, high-frame-rate ultrasound platform, vector flow estimation in each subject's right carotid bifurcation was performed through a multi-angle plane wave imaging (two transmission angles of 10° and -10°) formulation, and VPI cineloops were generated at a frame rate of 750 fps. Vector concentration was quantified by the resultant blood velocity vector angles within a region of interest; lower concentration indicated greater flow dispersion. Discrete concentration values during peak and late systole were compared across different segments of the carotid artery bifurcation before, and during, LBNP. RESULTS Vector projectile imaging revealed that external and internal carotid arteries exhibited regional hemodynamic changes during LBNP, which acted to reduce both the subject's cardiac output (Δ - 1.2 ± 0.5 L/min, -19%; P < 0.01) and peak carotid blood velocity (Δ - 6.30 ± 8.27 cm/s, -7%; P = 0.05). In these carotid artery branches, the vector concentration time trace before and during LBNP were observed to be different. The impact of LBNP on flow complexity in the two carotid artery branches showed variations between subjects. CONCLUSIONS Using VPI, intuitive visualization of complex hemodynamic changes can be obtained in healthy humans subjected to LBNP. This imaging tool has potential for further applications in vascular physiology to identify and quantify complex hemodynamic features in humans during different physiological stressor tests that regulate hemodynamics.
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Affiliation(s)
- Jason S Au
- Schlegel-University of Waterloo Research Institute for Aging, 250 Laurelwood Dr., Waterloo, N2J0E2, Canada.,Department of Electrical and Computer Engineering, University of Waterloo, 200 University Ave West, Waterloo, N2L3G1, Canada
| | - Billy Y S Yiu
- Schlegel-University of Waterloo Research Institute for Aging, 250 Laurelwood Dr., Waterloo, N2J0E2, Canada.,Department of Electrical and Computer Engineering, University of Waterloo, 200 University Ave West, Waterloo, N2L3G1, Canada
| | - Hélène So
- Faculty of Science and Engineering, Sorbonne Université, 75005, Paris, France
| | - Adrian J Y Chee
- Schlegel-University of Waterloo Research Institute for Aging, 250 Laurelwood Dr., Waterloo, N2J0E2, Canada.,Department of Electrical and Computer Engineering, University of Waterloo, 200 University Ave West, Waterloo, N2L3G1, Canada
| | - Danielle K Greaves
- Schlegel-University of Waterloo Research Institute for Aging, 250 Laurelwood Dr., Waterloo, N2J0E2, Canada.,University of Caen Normandy, Espl. De la Paix, 14032, Caen, France
| | - Richard L Hughson
- Schlegel-University of Waterloo Research Institute for Aging, 250 Laurelwood Dr., Waterloo, N2J0E2, Canada
| | - Alfred C H Yu
- Schlegel-University of Waterloo Research Institute for Aging, 250 Laurelwood Dr., Waterloo, N2J0E2, Canada.,Department of Electrical and Computer Engineering, University of Waterloo, 200 University Ave West, Waterloo, N2L3G1, Canada
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Al‐Khazraji BK, Badrov MB, Kadem M, Lingum NR, Birmingham TB, Shoemaker JK. Exploring Cerebrovascular Function in Osteoarthritis: "Heads-up". Physiol Rep 2019; 7:e14212. [PMID: 31660705 PMCID: PMC6817995 DOI: 10.14814/phy2.14212] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 07/26/2019] [Accepted: 07/30/2019] [Indexed: 11/24/2022] Open
Abstract
Individuals with osteoarthritis (OA) are at greater risk of cardiovascular and cerebrovascular incidents; yet, cerebrovascular control remains uncharacterized. Our primary outcome was to acquire cerebrovascular control metrics in patients with OA and compare measures to healthy control adults (CTL) without OA or cardiovascular complications. Our primary covariate was a 10-year risk factor for cardiovascular and stroke incidents, and secondary covariates were other cardiovascular disease risk factors (i.e., body mass index, carotid intima media thickness, and brachial flow-mediated dilation). Our secondary outcomes were to assess anatomical and functional changes that may be related to cerebrovascular reactivity were also acquired such as white matter lesion volume and brief cognitive assessments. In 25 adults (n = 13 CTL, n = 12 OA), under hypercapnia, magnetic resonance imaging (3T) was used to acquire a "Global Cerebrovascular Reactivity" index across the larger intracranial cerebral arteries and white matter lesions, and transcranial Doppler was used for both middle cerebral artery hemodynamic responses to hypercapnia and to assess autoregulation via a sit-to-stand task. Compared to CTL, OA had lower "Global Cerebrovascular Reactivity" index responses to hypercapnia, autoregulatory responses, and greater white matter lesions (P < 0.05). These differences persisted after covarying for the outlined primary and secondary covariates. Patients with OA, in the absence of known cardiovascular disease, can exhibit pre-clinical and impaired (compared to CTL) peripheral and cerebrovascular control metrics.
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Affiliation(s)
- Baraa K. Al‐Khazraji
- School of Kinesiology, Faculty of Health SciencesWestern UniversityLondonOntarioCanada
- Bone and Joint InstituteWestern UniversityLondonOntarioCanada
| | - Mark B. Badrov
- School of Kinesiology, Faculty of Health SciencesWestern UniversityLondonOntarioCanada
| | - Mason Kadem
- Brain and Mind InstituteWestern UniversityLondonOntarioCanada
| | - Navena R. Lingum
- School of Kinesiology, Faculty of Health SciencesWestern UniversityLondonOntarioCanada
| | - Trevor B. Birmingham
- School of Physical TherapyFaculty of Health SciencesWestern OntarioLondon, OntarioCanada
- Bone and Joint InstituteWestern UniversityLondonOntarioCanada
| | - Joel Kevin Shoemaker
- School of Kinesiology, Faculty of Health SciencesWestern UniversityLondonOntarioCanada
- Bone and Joint InstituteWestern UniversityLondonOntarioCanada
- Department of Physiology and Pharmacology, Schulich School of Medicine and DentistryWestern UniversityLondonOntarioCanada
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Hisdal J, Landsverk SA, Hoff IE, Hagen OA, Kirkebøen KA, Høiseth LØ. Associations between changes in precerebral blood flow and cerebral oximetry in the lower body negative pressure model of hypovolemia in healthy volunteers. PLoS One 2019; 14:e0219154. [PMID: 31251778 PMCID: PMC6599124 DOI: 10.1371/journal.pone.0219154] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Accepted: 06/17/2019] [Indexed: 11/19/2022] Open
Abstract
Reductions in cerebral oxygen saturation (ScO2) measured by near infra-red spectroscopy have been found during compensated hypovolemia in the lower body negative pressure (LBNP)-model, which may reflect reduced cerebral blood flow. However, ScO2 may also be contaminated from extracranial (scalp) tissues, mainly supplied by the external carotid artery (ECA), and it is possible that a ScO2 reduction during hypovolemia is caused by reduced scalp, and not cerebral, blood flow. The aim of the present study was to explore the associations between blood flow in precerebral arteries and ScO2 during LBNP-induced hypovolemia. Twenty healthy volunteers were exposed to LBNP 20, 40, 60 and 80 mmHg. Blood flow in the internal carotid artery (ICA), ECA and vertebral artery (VA) was measured by Doppler ultrasound. Stroke volume for calculating cardiac output was measured by suprasternal Doppler. Associations of changes within subjects were examined using linear mixed-effects regression models. LBNP reduced cardiac output, ScO2 and ICA and ECA blood flow. Changes in flow in both ICA and ECA were associated with changes in ScO2 and cardiac output. Flow in the VA did not change during LBNP and changes in VA flow were not associated with changes in ScO2 or cardiac output. During experimental compensated hypovolemia in healthy, conscious subjects, a reduced ScO2 may thus reflect a reduction in both cerebral and extracranial blood flow.
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Affiliation(s)
- Jonny Hisdal
- Section of Vascular Investigations, Department of Vascular Surgery, Division of Cardiovascular and Pulmonary Diseases, Oslo University Hospital, Oslo, Norway
- Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Svein Aslak Landsverk
- Department of Anesthesiology, Division of Emergencies and Critical Care, Oslo University Hospital, Oslo, Norway
| | - Ingrid Elise Hoff
- Department of Anesthesiology, Division of Emergencies and Critical Care, Oslo University Hospital, Oslo, Norway
- Norwegian Air Ambulance Foundation, Oslo, Norway
| | - Ove Andreas Hagen
- Department of Anesthesiology, Division of Emergencies and Critical Care, Oslo University Hospital, Oslo, Norway
| | - Knut Arvid Kirkebøen
- Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Anesthesiology, Division of Emergencies and Critical Care, Oslo University Hospital, Oslo, Norway
| | - Lars Øivind Høiseth
- Section of Vascular Investigations, Department of Vascular Surgery, Division of Cardiovascular and Pulmonary Diseases, Oslo University Hospital, Oslo, Norway
- Department of Anesthesiology, Division of Emergencies and Critical Care, Oslo University Hospital, Oslo, Norway
- * E-mail:
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Olesen ND, Nielsen HB, Olsen NV, Secher NH. The age-related reduction in cerebral blood flow affects vertebral artery more than internal carotid artery blood flow. Clin Physiol Funct Imaging 2019; 39:255-260. [PMID: 30897269 DOI: 10.1111/cpf.12568] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 03/18/2019] [Indexed: 11/26/2022]
Abstract
Ageing reduces cerebral blood flow (CBF), while mean arterial pressure (MAP) becomes elevated. According to 'the selfish brain' hypothesis of hypertension, a reduction in vertebral artery blood flow (VA) leads to increased sympathetic activity and thus increases MAP. In twenty-two young (24 ± 3 years; mean ± SD) and eleven elderly (70 ± 5 years) normotensive men, duplex ultrasound evaluated whether the age-related reduction in CBF affects VA more than internal carotid artery (ICA) blood flow. Pulse-contour analysis evaluated MAP while near-infrared spectroscopy determined frontal lobe oxygenation and transcranial Doppler middle cerebral artery mean blood velocity (MCA Vmean ). During supine rest, MAP (90 ± 13 versus 78 ± 9 mmHg; P<0·001) was elevated in the older subjects while their frontal lobe oxygenation (68 ± 7% versus 77 ± 7%; P<0·001), MCA Vmean (49 ± 9 versus 60 ± 12 cm s-1 ; P = 0·016) and CBF (754 ± 112 versus 900 ± 144 ml min-1 ; P = 0·004) were low reflected in VA (138 ± 48 versus 219 ± 50 ml min-1 ; P<0·001) rather than in ICA flow (616 ± 96 versus 680 ± 120 ml min-1 ; P = 0·099). In conclusion, blood supply to the brain and its oxygenation are affected by ageing and the age-related decline in VA flow appears to be four times as large as that in ICA and could be important for the age-related increase in MAP.
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Affiliation(s)
- Niels D Olesen
- Department of Anaesthesia, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Henning B Nielsen
- Department of Anaesthesia, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Niels V Olsen
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Niels H Secher
- Department of Anaesthesia, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
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Ota A, Takeda R, Imai D, Naghavi N, Kawai E, Saho K, Morita E, Suzuki Y, Yokoyama H, Miyagawa T, Okazaki K. The effects of aging on the distribution of cerebral blood flow with postural changes and mild hyperthermia. Eur J Appl Physiol 2019; 119:1261-1272. [DOI: 10.1007/s00421-019-04118-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 03/01/2019] [Indexed: 11/24/2022]
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45
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Ogoh S, Sato K, Hirasawa A, Sadamoto T. The effect of muscle metaboreflex on the distribution of blood flow in cerebral arteries during isometric exercise. J Physiol Sci 2019; 69:375-385. [PMID: 30604287 PMCID: PMC10717543 DOI: 10.1007/s12576-018-0653-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2018] [Accepted: 12/11/2018] [Indexed: 12/20/2022]
Abstract
The present study examined the effect of muscle metaboreflex on blood flow in different cerebral arteries. Eleven healthy participants performed isometric, one-leg knee extension at 30% maximal voluntary contraction for 2 min. Activated muscle metaboreflex was isolated for 2 min by post-exercise muscle ischemia (PEMI). The contralateral internal carotid (ICA), vertebral (VA), and ipsilateral external carotid arteries (ECA) blood flows were evaluated using Doppler ultrasound. The ICA blood flow increased at the beginning of exercise (P = 0.004) but returned to the baseline level at the end of exercise (P = 0.055). In contrast, the VA blood flow increased and it was maintained until the end of the exercise (P = 0.011), while the ECA blood flow gradually increased throughout the exercise (P = 0.001). These findings indicate that isometric exercise causes a heterogeneous cerebral blood flow response in different cerebral arteries. During PEMI, the conductance of the VA as well as that of the ICA was significantly lower compared with the baseline value (P = 0.020 and P = 0.032, at PEMI90), while the conductance of the ECA was not different from the baseline (P = 0.587), suggesting that the posterior and anterior cerebral vasculature were similarly affected during exercise by activation of muscle metaboreceptors, but not in the non-cerebral artery. Since ECA branches from ICA, the balance in the different influence of muscle metaboreflex on ECA (vasodilation via exercise-induced hypertension) and ICA (vasoconstriction) may contribute to the decrease in ICA blood flow at the end of isometric exercise.
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Affiliation(s)
- Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, 2100 Kujirai, Kawagoe-shi, Saitama, 350-8585, Japan.
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46
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Gibbons TD, Zuj KA, Peterson SD, Hughson RL. Comparison of pulse contour, aortic Doppler ultrasound and bioelectrical impedance estimates of stroke volume during rapid changes in blood pressure. Exp Physiol 2019; 104:368-378. [PMID: 30582758 DOI: 10.1113/ep087240] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 12/18/2018] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? Pulse contour analysis of the finger arterial pressure by Windkessel modelling is commonly used to estimate stroke volume continuously. But is it valid during dynamic changes in blood pressure? What is the main finding and its importance? Second-by-second analysis revealed that pulse contour analysis underestimated stroke volume by up to 25% after standing from a squat, and 16% after standing thigh-cuff release, when compared with aortic Doppler ultrasound estimates. These results reveal that pulse contour analysis of stroke volume should be interpreted with caution during rapid changes in physiological state. ABSTRACT Dynamic measurements of stroke volume (SV) and cardiac output provide an index of central haemodynamics during transitional states, such as postural changes and onset of exercise. The most widely used method to assess dynamic fluctuations in SV is the Modelflow method, which uses the arterial blood pressure waveform along with age- and sex-specific aortic properties to compute beat-to-beat estimates of aortic flow. Modelflow has been validated against more direct methods in steady-state conditions, but not during dynamic changes in physiological state, such as active orthostatic stress testing. In the present study, we compared the dynamic SV responses from Modelflow (SVMF ), aortic Doppler ultrasound (SVU/S ) and bioelectrical impedance analysis (SVBIA ) during two different orthostatic stress tests, a squat-to-stand (S-S) transition and a standing bilateral thigh-cuff release (TCR), in 15 adults (six females). Second-by-second analysis revealed that when compared with estimates of SV by aortic Doppler ultrasound, Modelflow underestimated SV by up to 25% from 3 to 11 s after standing from the squat position and by up to 16% from 3 to 7 s after TCR (P < 0.05). The SVMF and SVBIA were similar during the first minute of the S-S transition, but were different 3 s after TCR and at intermittent time points between 34 and 44 s (P < 0.05). These findings indicate that the physiological conditions elicited by orthostatic stress testing violate some of the inherent assumptions of Modelflow and challenge models used to interpret bioelectrical impedance responses, resulting in an underestimation in SV during rapid changes in physiological state.
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Affiliation(s)
- Travis D Gibbons
- Faculty of Applied Health Sciences, University of Waterloo, Waterloo, ON, Canada
| | - Kathryn A Zuj
- Faculty of Applied Health Sciences, University of Waterloo, Waterloo, ON, Canada
| | - Sean D Peterson
- Department of Mechanical and Mechatronic Engineering, University of Waterloo, Waterloo, ON, Canada
| | - Richard L Hughson
- Faculty of Applied Health Sciences, University of Waterloo, Waterloo, ON, Canada.,Schlegel-University of Waterloo Research Institute for Aging, Waterloo, ON, Canada
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Ní Bhuachalla B, McGarrigle CA, O'Leary N, Akuffo KO, Peto T, Beatty S, Kenny RA. Orthostatic blood pressure variability is associated with lower visual contrast sensitivity function: Findings from The Irish Longitudinal Study on Aging. Exp Gerontol 2019; 119:14-24. [PMID: 30677467 DOI: 10.1016/j.exger.2019.01.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 01/08/2019] [Accepted: 01/10/2019] [Indexed: 10/27/2022]
Abstract
BACKGROUND Hypertension is established to cause vascular end-organ damage. Other forms of dysregulated blood pressure (BP) behaviour, such as orthostatic hypotension have also been associated with cardiovascular (CV) events. The eye is potentially vulnerable to dysregulated systemic BP if ocular circulation autoregulation is impaired. We investigated whether phenotypes of abnormal BP stabilisation after orthostasis, an autonomic stressor, had a relationship with contrast sensitivity (CS), an outcome measure of subtle psychophysical visual function. METHODS This was a cross-sectional study from wave 1 of The Irish Longitudinal Study on Ageing (TILDA). From beat-to-beat orthostatic BP (BP), measured by digital photoplethysmography during active stand, 4 phenotypes have been defined 1) normal stabilisation 2) orthostatic hypotension, 3) orthostatic hypertension 4) BP variability. Contrast sensitivity was measured using a Functional Visual Analyzer. Multivariable linear regression models investigated the relationship between orthostatic BP phenotypes and contrast sensitivity in 4289 adults aged ≥50 years adjusting for, demographics, cardiovascular risk factors, self-reported eye pathologies, objective hypertension and antihypertensives. A sensitivity analysis adjusted for age-related macular degeneration, glaucoma, diabetic retinopathy and maculopathy identified on retinal photographs. Finally models were compared, adjusting for alternative measures of cataract versus not, to examine the potential effect of cataract on any associations. RESULTS Systolic orthostatic BP variability was associated with worse contrast sensitivity, in the primary and the sensitivity analysis. Adjusting for alternative measures of clinical cataract attenuated the association by 18%. CONCLUSIONS Orthostatic BP variability is associated with worse contrast sensitivity, independent of hypertension and retinal pathology and may be a cardiovascular biomarker of early ocular pathology.
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Affiliation(s)
- Bláithín Ní Bhuachalla
- Department of Medical Gerontology, School of Medicine, Trinity College Dublin, The University of Dublin, Old Stone Building, Trinity Centre for Health Sciences, St James's Hospital, James's Street, Dublin 8, Ireland.
| | - Christine A McGarrigle
- The Irish Longitudinal Study on Aging (TILDA), Lincoln Gate, Trinity College Dublin, The University of Dublin, College Green, Dublin 2, Ireland.
| | - Neil O'Leary
- The Irish Longitudinal Study on Aging (TILDA), Lincoln Gate, Trinity College Dublin, The University of Dublin, College Green, Dublin 2, Ireland.
| | - Kwadwo Owusu Akuffo
- Department of Optometry and Visual Science, College of Science, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
| | - Tunde Peto
- Head of Reading Centre, Department of Research and Development, National Institute of Health Research Biomedical Research Centre at Moorfields Eye Hospital National Health Service Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom.
| | - Stephen Beatty
- Macular Pigment Research Group, Vision Research Centre, Carriganore House, Waterford Institute of Technology, Waterford, Ireland.
| | - Rose Anne Kenny
- Department of Medical Gerontology, School of Medicine, Trinity College Dublin, The University of Dublin, Old Stone Building, Trinity Centre for Health Sciences, St James's Hospital, James's Street, Dublin 8, Ireland; The Irish Longitudinal Study on Aging (TILDA), Lincoln Gate, Trinity College Dublin, The University of Dublin, College Green, Dublin 2, Ireland.
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48
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Washio T, Vranish JR, Kaur J, Young BE, Katayama K, Fadel PJ, Ogoh S. Acute reduction in posterior cerebral blood flow following isometric handgrip exercise is augmented by lower body negative pressure. Physiol Rep 2018; 6:e13886. [PMID: 30338667 PMCID: PMC6194212 DOI: 10.14814/phy2.13886] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 09/16/2018] [Indexed: 01/31/2023] Open
Abstract
The mechanism(s) for the increased occurrence of a grayout or blackout, syncope, immediately after heavy resistance exercise are unclear. It is well-known that orthostatic stress increases the occurrence of postexercise syncope. In addition, previous findings have suggested that hypo-perfusion, especially in the posterior cerebral circulation rather than anterior cerebral circulation, may be associated with the occurrence of syncope. Herein, we hypothesized that the postexercise decrease in posterior, but not anterior, cerebral blood flow (CBF) would be greater during orthostatic stress. Nine healthy subjects performed 3-min isometric handgrip (HG) at 30% maximum voluntary contraction without (CONTROL) and during lower body negative pressure (LBNP; -40 Torr) while vertebral artery (VA) blood flow, as an index of posterior CBF, and middle cerebral artery blood velocity (MCAv), as an index of anterior CBF, were measured. Immediately after HG (0 to 15 sec of recovery phase), mean arterial pressure decreased but there was no difference in this reduction between CONTROL and LBNP conditions (-15.4 ± 4.0% and -17.0 ± 6.2%, P = 0.42). Similarly, MCAv decreased following exercise and was unaffected by the application of LBNP (P = 0.22). In contrast, decreases in VA blood flow immediately following HG during LBNP were significantly greater compared to CONTROL condition (-24.2 ± 9.5% and -13.4 ± 6.6%, P = 0.005). These findings suggest that the decrease in posterior CBF immediately following exercise was augmented by LBNP, whereas anterior CBF appeared unaffected. Thus, the posterior cerebral circulation may be more sensitive to orthostatic stress during the postexercise period.
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Affiliation(s)
- Takuro Washio
- Department of Biomedical EngineeringToyo UniversityKawagoe‐shiSaitamaJapan
- Research Fellow of Japan Society for the Promotion of ScienceTokyoJapan
| | | | - Jasdeep Kaur
- Department of KinesiologyUniversity of Texas at ArlingtonArlingtonTexas
| | - Benjamin E. Young
- Department of KinesiologyUniversity of Texas at ArlingtonArlingtonTexas
| | - Keisho Katayama
- Research Center of HealthPhysical Fitness and SportsNagoya UniversityNagoyaJapan
| | - Paul J. Fadel
- Department of KinesiologyUniversity of Texas at ArlingtonArlingtonTexas
| | - Shigehiko Ogoh
- Department of Biomedical EngineeringToyo UniversityKawagoe‐shiSaitamaJapan
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Kleczyński P, Dimitrow PP, Dziewierz A, Wiktorowicz A, Rakowski T, Surdacki A, Dudek D. Predictors of syncope in patients with severe aortic stenosis: The role of orthostatic unload test. Cardiol J 2018; 27:749-755. [PMID: 30234894 DOI: 10.5603/cj.a2018.0107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 09/13/2018] [Accepted: 09/01/2018] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND There is a paucity of data regarding response of cerebral blood flow to the postural unloading maneuver and its impact on the risk of syncope in patients with aortic stenosis (AS). The aim of the present study was to assess effects of orthostatic stress test on changes in carotid and vertebral artery blood flow and its association with syncope in patients with severe AS. METHODS 108 patients were enrolled (72 with and 36 patients without syncope) with severe isolated severe AS. Peak systolic blood-flow velocity (PSV) and end-diastolic velocity in the carotid arteries and vertebral arteries were measured by duplex ultrasound in the supine position and at 1-2 min after the assumption of the standing position. RESULTS The orthostatic stress test induced a significant decrease in carotid and vertebral arterial flow velocities in all examined arteries (p < 0.001). The median (interquartile range) of mean change in PSV for carotid arteries was higher for patients with syncope (syncope [-] vs. syncope [+]: -0.6 cm/s [-1.8, 1.0] vs. -7.3 cm/s [-9.5, -2.0]; p < 0.001) and similarly for vertebral arteries (-0.5 cm/s [-2.0, 0.5] vs. -4.8 cm/s [-6.5, -1.3]; p < 0.001, respectively). Age, aortic valve area, and mean change in PSV for carotid arteries were independently associated with syncope. CONCLUSIONS In patients with AS, a decrease in carotid and vertebral arterial flow velocities in the standing position was observed and was associated with syncope. The present findings may support the value of an orthostatic test in identifying patients with severe AS and a high risk of syncope.
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50
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Caldwell HG. Emerging views of how changes in blood pressure influence cerebral blood flow. J Physiol 2018; 596:4565-4567. [PMID: 30084502 DOI: 10.1113/jp276800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Hannah G Caldwell
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Okanagan, Kelowna, Canada
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