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Claassen JAHR, Thijssen DHJ, Panerai RB, Faraci FM. Regulation of cerebral blood flow in humans: physiology and clinical implications of autoregulation. Physiol Rev 2021; 101:1487-1559. [PMID: 33769101 PMCID: PMC8576366 DOI: 10.1152/physrev.00022.2020] [Citation(s) in RCA: 292] [Impact Index Per Article: 97.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Brain function critically depends on a close matching between metabolic demands, appropriate delivery of oxygen and nutrients, and removal of cellular waste. This matching requires continuous regulation of cerebral blood flow (CBF), which can be categorized into four broad topics: 1) autoregulation, which describes the response of the cerebrovasculature to changes in perfusion pressure; 2) vascular reactivity to vasoactive stimuli [including carbon dioxide (CO2)]; 3) neurovascular coupling (NVC), i.e., the CBF response to local changes in neural activity (often standardized cognitive stimuli in humans); and 4) endothelium-dependent responses. This review focuses primarily on autoregulation and its clinical implications. To place autoregulation in a more precise context, and to better understand integrated approaches in the cerebral circulation, we also briefly address reactivity to CO2 and NVC. In addition to our focus on effects of perfusion pressure (or blood pressure), we describe the impact of select stimuli on regulation of CBF (i.e., arterial blood gases, cerebral metabolism, neural mechanisms, and specific vascular cells), the interrelationships between these stimuli, and implications for regulation of CBF at the level of large arteries and the microcirculation. We review clinical implications of autoregulation in aging, hypertension, stroke, mild cognitive impairment, anesthesia, and dementias. Finally, we discuss autoregulation in the context of common daily physiological challenges, including changes in posture (e.g., orthostatic hypotension, syncope) and physical activity.
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Affiliation(s)
- Jurgen A H R Claassen
- Department of Geriatrics, Radboud University Medical Center, Donders Institute for Brain, Cognition, and Behaviour, Nijmegen, The Netherlands
| | - Dick H J Thijssen
- Department of Physiology, Radboud Institute for Health Sciences, Nijmegen, The Netherlands
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - Ronney B Panerai
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- >National Institute for Health Research Leicester Biomedical Research Centre, University of Leicester, Leicester, United Kingdom
| | - Frank M Faraci
- Departments of Internal Medicine, Neuroscience, and Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, Iowa
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Amelard R, Murray KR, Hedge ET, Cleworth TW, Noguchi M, Laing AC, Hughson RL. Monocular 3D Sway Tracking for Assessing Postural Instability in Cerebral Hypoperfusion During Quiet Standing. IEEE Trans Neural Syst Rehabil Eng 2020; 28:720-729. [PMID: 32012020 DOI: 10.1109/tnsre.2020.2971340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Postural instability is prevalent in aging and neurodegenerative disease, decreasing quality of life and independence. Quantitatively monitoring balance control is important for assessing treatment efficacy and rehabilitation progress. However, existing technologies for assessing postural sway are complex and expensive, limiting their widespread utility. Here, we propose a monocular imaging system capable of assessing sub-millimeter 3D sway dynamics during quiet standing. Two anatomical targets with known feature geometries were placed on the lumbar and shoulder. Upper and lower trunk 3D kinematic motion were automatically assessed from a set of 2D frames through geometric feature tracking and an inverse motion model. Sway was tracked in 3D and compared between control and hypoperfusion conditions in 14 healthy young adults. The proposed system demonstrated high agreement with a commercial motion capture system (error [Formula: see text], [-0.52, 0.52]). Between-condition differences in sway dynamics were observed in anterior-posterior sway during early and mid stance, and medial-lateral sway during mid stance commensurate with decreased cerebral perfusion, followed by recovered sway dynamics during late stance with cerebral perfusion recovery. This inexpensive single-camera system enables quantitative 3D sway monitoring for assessing neuromuscular balance control in weakly constrained environments.
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Prevalence and factors related to orthostatic syndromes in recently diagnosed, drug-naïve patients with Parkinson disease. Clin Auton Res 2019; 30:265-271. [DOI: 10.1007/s10286-019-00652-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 12/02/2019] [Indexed: 12/15/2022]
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Fitzgibbon-Collins LK, Noguchi M, Heckman GA, Hughson RL, Robertson AD. Acute reduction in cerebral blood velocity on supine-to-stand transition increases postural instability in young adults. Am J Physiol Heart Circ Physiol 2019; 317:H1342-H1353. [PMID: 31674810 DOI: 10.1152/ajpheart.00360.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We tested the hypothesis that transient deficits in cerebral blood flow are associated with postural sway. In 19 young, healthy adults, we examined the association between the drop in cerebral blood flow during supine-to-stand transitions, indexed by transcranial Doppler ultrasound [middle cerebral artery blood velocity at diastole (MCAdv)] and near-infrared spectroscopy [tissue saturation index (TSI)] and the center of pressure displacement while standing. Participants performed transitions under three conditions aimed at progressively increasing the drop in MCAdv, in a randomized order: 1) a control transition (Con); 2) a transition that coincided with deflation of bilateral thigh cuffs; and 3) a transition that coincided with both thigh-cuff deflation and 90 s of prior hyperventilation (HTC). The deficit in diastolic blood velocity (MCAdv deficit) was quantified as the difference between MCAdv and its preceding baseline value, summed over 10 s, beginning at the MCAdv nadir. Compared with Con, HTC led to greater drops in MCAdv (P = 0.003) and TSI (P < 0.001) at nadir. The MCAdv deficit was positively associated with the center of pressure displacement vector-average using repeated-measures correlation (repeated-measures correlation coefficient = 0.56, P < 0.001). An a posteriori analysis identified a sub-group of participants that showed an exaggerated increase in MCAdv deficit and greater postural instability in both the anterior-posterior (P = 0.002) and medial-lateral (P = 0.021) directions in response to the interventions. These findings support the theory that individuals who experience greater initial cerebral hypoperfusion on standing may be at a greater risk for falls.NEW & NOTEWORTHY Dizziness and risk for falls after standing might link directly to reduced delivery of oxygen to the brain. By introducing challenges that increased the drop in brain blood flow in healthy young adults, we have shown for the first time a direct link to greater postural instability. These results point to a need to measure cerebral blood flow and/or oxygenation after postural transitions in populations, such as older adults, to assist in fall risk assessment.
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Affiliation(s)
| | | | - George A Heckman
- Schlegel-University of Waterloo Research Institute for Aging, Waterloo, Ontario, Canada
| | - Richard L Hughson
- Schlegel-University of Waterloo Research Institute for Aging, Waterloo, Ontario, Canada
| | - Andrew D Robertson
- Schlegel-University of Waterloo Research Institute for Aging, Waterloo, Ontario, Canada
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de Rodez Benavent SA, Nygaard GO, Nilsen KB, Etholm L, Sowa P, Wendel-Haga M, Harbo HF, Drolsum L, Laeng B, Kerty E, Celius EG. Neurodegenerative Interplay of Cardiovascular Autonomic Dysregulation and the Retina in Early Multiple Sclerosis. Front Neurol 2019; 10:507. [PMID: 31156539 PMCID: PMC6529954 DOI: 10.3389/fneur.2019.00507] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 04/26/2019] [Indexed: 11/27/2022] Open
Abstract
Introduction: Autonomic nervous system (ANS) symptoms are prevalent in multiple sclerosis (MS) as is neurodegeneration. Our aim was to explore the occurrence of ANS symptoms and retinal neurodegeneration in a newly diagnosed MS population with tools available in a clinical setting. Methods: Forty-three MS patients and 44 healthy controls took part in the study. We employed a bedside cardiovascular ANS test battery together with classical pupillometry, optical coherence tomography (OCT) evaluation of retinal neurodegeneration in eyes without previous optic neuritis (MSNON) and patients' self-report forms on fatigue, orthostatic and ANS symptoms. Results: Half of the patients presented with ANS symptoms and a high level of fatigue. There was a significant difference in ganglion cell layer thickness (mean GCIPL) evaluated by OCT in MSNON compared to healthy control eyes. We found a negative linearity of mean GCIPL on group level with increasing disease duration. Three patients fulfilled the criteria of postural orthostatic tachycardia syndrome (POTS). Conclusion: Our results demonstrate retinal neurodegeneration in MSNON, a high frequency of fatigue and a high prevalence of ANS symptoms in newly diagnosed patients. Whether neurodegeneration precedes ANS dysfunction or vice versa is still open to debate, but as unveiled by the presence of POTS in this MS population, differences in stress-response regulation add to the understanding of variation in onset-time of ANS dysfunction in early MS.
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Affiliation(s)
- Sigrid A de Rodez Benavent
- Department of Ophthalmology, Oslo University Hospital, Oslo, Norway.,Faculty of Medicine, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Gro O Nygaard
- Department of Neurology, Oslo University Hospital, Oslo, Norway
| | - Kristian B Nilsen
- Section for Clinical Neurophysiology, Department of Neurology, Oslo University Hospital, Oslo, Norway.,Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway
| | - Lars Etholm
- Section for Clinical Neurophysiology, Department of Neurology, Oslo University Hospital, Oslo, Norway
| | - Piotr Sowa
- Division of Radiology and Nuclear Medicine, Oslo University Hospital, Oslo, Norway
| | - Marte Wendel-Haga
- Department of Neurology, Oslo University Hospital, Oslo, Norway.,Department of Neurology, Telemark Hospital, Skien, Norway
| | - Hanne F Harbo
- Faculty of Medicine, Institute of Clinical Medicine, University of Oslo, Oslo, Norway.,Department of Neurology, Oslo University Hospital, Oslo, Norway
| | - Liv Drolsum
- Department of Ophthalmology, Oslo University Hospital, Oslo, Norway.,Faculty of Medicine, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Bruno Laeng
- Department of Psychology, University of Oslo, Oslo, Norway
| | - Emilia Kerty
- Faculty of Medicine, Institute of Clinical Medicine, University of Oslo, Oslo, Norway.,Department of Neurology, Oslo University Hospital, Oslo, Norway
| | - Elisabeth G Celius
- Faculty of Medicine, Institute of Clinical Medicine, University of Oslo, Oslo, Norway.,Department of Neurology, Oslo University Hospital, Oslo, Norway
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Stewart JM, Boris JR, Chelimsky G, Fischer PR, Fortunato JE, Grubb BP, Heyer GL, Jarjour IT, Medow MS, Numan MT, Pianosi PT, Singer W, Tarbell S, Chelimsky TC. Pediatric Disorders of Orthostatic Intolerance. Pediatrics 2018; 141:peds.2017-1673. [PMID: 29222399 PMCID: PMC5744271 DOI: 10.1542/peds.2017-1673] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/06/2017] [Indexed: 01/18/2023] Open
Abstract
Orthostatic intolerance (OI), having difficulty tolerating an upright posture because of symptoms or signs that abate when returned to supine, is common in pediatrics. For example, ∼40% of people faint during their lives, half of whom faint during adolescence, and the peak age for first faint is 15 years. Because of this, we describe the most common forms of OI in pediatrics and distinguish between chronic and acute OI. These common forms of OI include initial orthostatic hypotension (which is a frequently seen benign condition in youngsters), true orthostatic hypotension (both neurogenic and nonneurogenic), vasovagal syncope, and postural tachycardia syndrome. We also describe the influences of chronic bed rest and rapid weight loss as aggravating factors and causes of OI. Presenting signs and symptoms are discussed as well as patient evaluation and testing modalities. Putative causes of OI, such as gravitational and exercise deconditioning, immune-mediated disease, mast cell activation, and central hypovolemia, are described as well as frequent comorbidities, such as joint hypermobility, anxiety, and gastrointestinal issues. The medical management of OI is considered, which includes both nonpharmacologic and pharmacologic approaches. Finally, we discuss the prognosis and long-term implications of OI and indicate future directions for research and patient management.
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Affiliation(s)
| | | | | | | | - John E. Fortunato
- Ann and Robert H. Lurie Children’s Hospital of Chicago, Chicago, Illinois
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Barochiner J, Aparicio LS, Alfie J, Rada MA, Morales MS, Galarza CR, Cuffaro PE, Marín MJ, Martínez R, Waisman GD. Hemodynamic characterization of hypertensive patients with an exaggerated orthostatic blood pressure variation. Clin Exp Hypertens 2017; 40:287-291. [PMID: 28895755 DOI: 10.1080/10641963.2017.1368539] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Exaggerated orthostatic blood pressure variation (EOV) is a poorly understood phenomenon related to high cardiovascular risk. We aimed to determine whether hypertensive patients with EOV have a distinct hemodynamic pattern, assessed through impedance cardiography. METHODS In treated hypertensive patients, we measured the cardiac index (CI), systemic vascular resistance index (SVRI), blood pressure (BP), and heart rate (HR) in the supine and standing (after 3 minutes) positions, defining three groups according to BP variation: 1) Normal orthostatic BP variation (NOV): standing systolic BP (stSBP)-supine systolic BP (suSBP) between -20 and 20 mmHg and standing diastolic BP (stDBP)-supine diastolic BP (suDBP) between -10 and 10 mmHg; 2) orthostatic hypotension (OHypo): stSBP-suSBP≤-20 or stDBP-suDBP≤-10 mmHg; 3) orthostatic hypertension (OHyper): stSBP-suSBP≥20 or stDBP-suDBP≥10 mmHg. We performed multivariable analyses to determine the association of hemodynamic variables with EOV. RESULTS We included 186 patients. Those with OHyper had lower suDBP and higher orthostatic SVRI variation compared to NOV. In multivariable analyses, orthostatic HR variation (OR = 1.06 (95%CI 1.01-1.13), p = 0.03) and orthostatic SVRI variation (OR = 1.16 (95%CI 1.06-1.28), p = 0.002) were independently related to OHyper. No variables were independently associated with OHypo. CONCLUSION Patients with OHyper have a distinct hemodynamic pattern, with an exaggerated increase in SVRI and HR when standing.
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Affiliation(s)
- Jessica Barochiner
- a Hypertension Section, Internal Medicine Department , Hospital Italiano de Buenos Aires , Buenos Aires , Argentina
| | - Lucas S Aparicio
- a Hypertension Section, Internal Medicine Department , Hospital Italiano de Buenos Aires , Buenos Aires , Argentina
| | - José Alfie
- a Hypertension Section, Internal Medicine Department , Hospital Italiano de Buenos Aires , Buenos Aires , Argentina
| | - Marcelo A Rada
- a Hypertension Section, Internal Medicine Department , Hospital Italiano de Buenos Aires , Buenos Aires , Argentina
| | - Margarita S Morales
- a Hypertension Section, Internal Medicine Department , Hospital Italiano de Buenos Aires , Buenos Aires , Argentina
| | - Carlos R Galarza
- a Hypertension Section, Internal Medicine Department , Hospital Italiano de Buenos Aires , Buenos Aires , Argentina
| | - Paula E Cuffaro
- a Hypertension Section, Internal Medicine Department , Hospital Italiano de Buenos Aires , Buenos Aires , Argentina
| | - Marcos J Marín
- a Hypertension Section, Internal Medicine Department , Hospital Italiano de Buenos Aires , Buenos Aires , Argentina
| | - Rocío Martínez
- a Hypertension Section, Internal Medicine Department , Hospital Italiano de Buenos Aires , Buenos Aires , Argentina
| | - Gabriel D Waisman
- a Hypertension Section, Internal Medicine Department , Hospital Italiano de Buenos Aires , Buenos Aires , Argentina
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Schiffrin EL, Calhoun DA, Flack JM, Ito S, Webb RC. Update From the Editors to Our Readers. Am J Hypertens 2017; 30:1-2. [PMID: 27940428 DOI: 10.1093/ajh/hpw141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Ernesto L Schiffrin
- Sir Mortimer B. Davis-Jewish General Hospital, McGill University, Montreal, Quebec, Canada;
| | | | - John M Flack
- Southern Illinois University, Springfield, Illinois, USA
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