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Pérez-Denia L, Claffey P, O'Reilly A, Delgado-Ortet M, Rice C, Kenny RA, Finucane C. Cerebral Oxygenation Responses to Standing in Young Patients with Vasovagal Syncope. J Clin Med 2023; 12:4202. [PMID: 37445237 DOI: 10.3390/jcm12134202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 06/05/2023] [Accepted: 06/07/2023] [Indexed: 07/15/2023] Open
Abstract
Vasovagal syncope (VVS) is common in young adults and is attributed to cerebral hypoperfusion. However, during active stand (AS) testing, only peripheral and not cerebral hemodynamic responses are measured. We sought to determine whether cerebral oxygenation responses to an AS test were altered in young VVS patients when compared to the young healthy controls. A sample of young healthy adults and consecutive VVS patients attending a Falls and Syncope unit was recruited. Continuous beat-to-beat blood pressure (BP), heart rate, near-infrared spectroscopy (NIRS)-derived tissue saturation index (TSI), and changes in concentration of oxygenated/deoxygenated Δ[O2Hb]/Δ[HHb] hemoglobin were measured. BP and NIRS-derived features included nadir, peak, overshoot, trough, recovery rate, normalized recovery rate, and steady-state. Multivariate linear regression was used to adjust for confounders and BP. In total, 13 controls and 27 VVS patients were recruited. While no significant differences were observed in the TSI and Δ[O2Hb], there was a significantly smaller Δ[HHb] peak-to-trough and faster Δ[HHb] recovery rate in VVS patients, independent of BP. A higher BP steady-state was observed in patients but did not remain significant after multiple comparison correction. Young VVS patients demonstrated a similar cerebral circulatory response with signs of altered peripheral circulation with respect to the controls, potentially due to a hyper-reactive autonomic nervous system. This study sets the grounds for future investigations to understand the role of cerebral regulation during standing in VVS.
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Affiliation(s)
- Laura Pérez-Denia
- School of Medicine, Trinity College Dublin, D02 K6K6 Dublin, Ireland
- Mercer's Institute for Successful Ageing, St. James's Hospital Dublin, D08 TYF3 Dublin, Ireland
- Department of Medical Physics, Mercer's Institute for Successful Ageing, St. James's Hospital Dublin, D08 C9X2 Dublin, Ireland
| | - Paul Claffey
- School of Medicine, Trinity College Dublin, D02 K6K6 Dublin, Ireland
- Mercer's Institute for Successful Ageing, St. James's Hospital Dublin, D08 TYF3 Dublin, Ireland
| | - Ailbhe O'Reilly
- Mercer's Institute for Successful Ageing, St. James's Hospital Dublin, D08 TYF3 Dublin, Ireland
- Department of Bioengineering, School of Mechanical Engineering, Trinity College Dublin, D02 PN40 Dublin, Ireland
| | | | - Ciara Rice
- Mercer's Institute for Successful Ageing, St. James's Hospital Dublin, D08 TYF3 Dublin, Ireland
| | - Rose Anne Kenny
- School of Medicine, Trinity College Dublin, D02 K6K6 Dublin, Ireland
- Mercer's Institute for Successful Ageing, St. James's Hospital Dublin, D08 TYF3 Dublin, Ireland
| | - Ciarán Finucane
- School of Medicine, Trinity College Dublin, D02 K6K6 Dublin, Ireland
- Mercer's Institute for Successful Ageing, St. James's Hospital Dublin, D08 TYF3 Dublin, Ireland
- Department of Medical Physics, Mercer's Institute for Successful Ageing, St. James's Hospital Dublin, D08 C9X2 Dublin, Ireland
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Meijs TA, van Tuijl RJ, van den Brink H, Weaver NA, Siero JCW, van der Worp HB, Braun KPJ, Leiner T, de Jong PA, Zwanenburg JJM, Doevendans PA, Voskuil M, Grotenhuis HB. Assessment of aortic and cerebral haemodynamics and vascular brain injury with 3 and 7 T magnetic resonance imaging in patients with aortic coarctation. EUROPEAN HEART JOURNAL OPEN 2023; 3:oead001. [PMID: 36751560 PMCID: PMC9898880 DOI: 10.1093/ehjopen/oead001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 12/23/2022] [Accepted: 01/09/2023] [Indexed: 01/12/2023]
Abstract
Aims Coarctation of the aorta (CoA) is characterized by a central arteriopathy resulting in increased arterial stiffness. The condition is associated with an increased risk of stroke. We aimed to assess the aortic and cerebral haemodynamics and the presence of vascular brain injury in patients with previous surgical CoA repair. Methods and results Twenty-seven patients with CoA (median age 22 years, range 12-72) and 25 age- and sex-matched controls (median age 24 years, range 12-64) underwent 3 T (heart, aorta, and brain) and 7 T (brain) magnetic resonance imaging scans. Haemodynamic parameters were measured using two-dimensional phase-contrast images of the ascending and descending aorta, internal carotid artery (ICA), basilar artery (BA), middle cerebral artery (MCA), and perforating arteries. Vascular brain injury was assessed by rating white matter hyperintensities, cortical microinfarcts, lacunes, and microbleeds. Pulse wave velocities in the aortic arch and descending aorta were increased and ascending aortic distensibility was decreased in patients with CoA vs. controls. Patients with CoA showed a higher mean flow velocity in the right ICA, left ICA, and BA and a reduced distensibility in the right ICA, BA, and left MCA. Haemodynamic parameters in the perforating arteries, total cerebral blood flow, intracranial volumes, and vascular brain injury were similar between the groups. Conclusion Patients with CoA show an increased flow velocity and reduced distensibility in the aorta and proximal cerebral arteries, which suggests the presence of a generalized arteriopathy that extends into the cerebral arterial tree. No substantial vascular brain injury was observed in this relatively young CoA population, although the study was inadequately powered regarding this endpoint.
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Affiliation(s)
| | - Rick J van Tuijl
- Department of Radiology, University Medical Center Utrecht, Heidelberglaan 100, 3584CX Utrecht, The Netherlands
| | - Hilde van den Brink
- Department of Neurology and Neurosurgery, Brain Center, University Medical Center Utrecht, Heidelberglaan 100, 3584CX Utrecht, The Netherlands
| | - Nick A Weaver
- Department of Neurology and Neurosurgery, Brain Center, University Medical Center Utrecht, Heidelberglaan 100, 3584CX Utrecht, The Netherlands
| | - Jeroen C W Siero
- Department of Radiology, University Medical Center Utrecht, Heidelberglaan 100, 3584CX Utrecht, The Netherlands
| | - H Bart van der Worp
- Department of Neurology and Neurosurgery, Brain Center, University Medical Center Utrecht, Heidelberglaan 100, 3584CX Utrecht, The Netherlands
| | - Kees P J Braun
- Department of Neurology and Neurosurgery, Brain Center, University Medical Center Utrecht, Heidelberglaan 100, 3584CX Utrecht, The Netherlands
| | - Tim Leiner
- Department of Radiology, University Medical Center Utrecht, Heidelberglaan 100, 3584CX Utrecht, The Netherlands
| | - Pim A de Jong
- Department of Radiology, University Medical Center Utrecht, Heidelberglaan 100, 3584CX Utrecht, The Netherlands
| | - Jaco J M Zwanenburg
- Department of Radiology, University Medical Center Utrecht, Heidelberglaan 100, 3584CX Utrecht, The Netherlands
| | - Pieter A Doevendans
- Department of Cardiology, University Medical Center Utrecht, Heidelberglaan 100, 3584CX Utrecht, The Netherlands,Netherlands Heart Institute, Moreelsepark 1, 3511 EP Utrecht, The Netherlands,Department of Cardiology, Central Military Hospital, Lundlaan 1, 3584 EZ Utrecht, The Netherlands
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The Influence of Carbon Dioxide on Cerebral Autoregulation During Sevoflurane-based Anesthesia in Patients With Type 2 Diabetes. J Neurosurg Anesthesiol 2023; 35:65-73. [PMID: 34387283 DOI: 10.1097/ana.0000000000000794] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 07/06/2021] [Indexed: 02/07/2023]
Abstract
BACKGROUND Cerebral autoregulation (CA) continuously adjusts cerebrovascular resistance to maintain cerebral blood flow (CBF) constant despite changes in blood pressure. Also, CBF is proportional to changes in arterial carbon dioxide (CO 2 ) (cerebrovascular CO 2 reactivity). Hypercapnia elicits cerebral vasodilation that attenuates CA efficacy, while hypocapnia produces cerebral vasoconstriction that enhances CA efficacy. In this study, we quantified the influence of sevoflurane anesthesia on CO 2 reactivity and the CA-CO 2 relationship. METHODS We studied patients with type 2 diabetes mellitus (DM), prone to cerebrovascular disease, and compared them to control subjects. In 33 patients (19 DM, 14 control), end-tidal CO 2 , blood pressure, and CBF velocity were monitored awake and during sevoflurane-based anesthesia. CA, calculated with transfer function analysis assessing phase lead (degrees) between low-frequency oscillations in CBF velocity and mean arterial blood pressure, was quantified during hypocapnia, normocapnia, and hypercapnia. RESULTS In both control and DM patients, awake CO 2 reactivity was smaller (2.8%/mm Hg CO 2 ) than during sevoflurane anesthesia (3.9%/mm Hg; P <0.005). Hyperventilation increased CA efficacy more (3 deg./mm Hg CO 2 ) in controls than in DM patients (1.8 deg./mm Hg CO 2 ; P <0.001) in both awake and sevoflurane-anesthetized states. CONCLUSIONS The CA-CO 2 relationship is impaired in awake patients with type 2 DM. Sevoflurane-based anesthesia does not further impair this relationship. In patients with DM, hypocapnia induces cerebral vasoconstriction, but CA efficacy does not improve as observed in healthy subjects.
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Wan Y, Teng X, Li S, Yang Y. Application of transcranial Doppler in cerebrovascular diseases. Front Aging Neurosci 2022; 14:1035086. [PMID: 36425321 PMCID: PMC9679782 DOI: 10.3389/fnagi.2022.1035086] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 10/24/2022] [Indexed: 01/03/2024] Open
Abstract
Transcranial Doppler (TCD) is a rapid and non-invasive diagnostic technique that can provide real-time measurements of the relative changes in cerebral blood velocity (CBV). Therefore, TCD is a useful tool in the diagnosis and treatment of clinical cerebrovascular diseases (CVDs). In this review, the basic principles of TCD and its application in CVD were outlined. Specifically, TCD could be applied to evaluate occlusive CVD, assess collateral circulation in patients with ischemic stroke, and monitor cerebral vascular occlusion before and after thrombolysis as well as cerebral vasospasm (VSP) and microembolization signals after aneurysmal subarachnoid hemorrhage (SAH). Moreover, TCD could predict short-term stroke and transient cerebral ischemia in patients with anterior circulation occlusion treated with endovascular therapy and in patients with anterior circulation vascular occlusion. Additionally, TCD not only could monitor blood velocity signals during carotid endarterectomy (CEA) or carotid artery stenting (CAS) but also allowed earlier intervention through early recognition of sickle cell disease (SCD). Presently, TCD is a useful prognostic tool to guide the treatment of CVD. On the one hand, TCD is more commonly applied in clinical research, and on the other hand, TCD has an increasing role in the management of patients. Collectively, we review the principles and clinical application of TCD and propose some new research applications for TCD.
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Affiliation(s)
| | | | | | - Yanchao Yang
- Department of Anesthesiology, Shengjing Hospital of China Medical University, Shenyang, China
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Personalised physiological medicine: Orthostatic hypotension. Med Hypotheses 2022. [DOI: 10.1016/j.mehy.2022.110928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Barloese MCJ, Bauer C, Petersen ET, Hansen CS, Madsbad S, Siebner HR. Neurovascular Coupling in Type 2 Diabetes With Cognitive Decline. A Narrative Review of Neuroimaging Findings and Their Pathophysiological Implications. Front Endocrinol (Lausanne) 2022; 13:874007. [PMID: 35860697 PMCID: PMC9289474 DOI: 10.3389/fendo.2022.874007] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 05/17/2022] [Indexed: 01/21/2023] Open
Abstract
Type 2 diabetes causes substantial long-term damage in several organs including the brain. Cognitive decline is receiving increased attention as diabetes has been established as an independent risk factor along with the identification of several other pathophysiological mechanisms. Early detection of detrimental changes in cerebral blood flow regulation may represent a useful clinical marker for development of cognitive decline for at-risk persons. Technically, reliable evaluation of neurovascular coupling is possible with several caveats but needs further development before it is clinically convenient. Different modalities including ultrasound, positron emission tomography and magnetic resonance are used preclinically to shed light on the many influences on vascular supply to the brain. In this narrative review, we focus on the complex link between type 2 diabetes, cognition, and neurovascular coupling and discuss how the disease-related pathology changes neurovascular coupling in the brain from the organ to the cellular level. Different modalities and their respective pitfalls are covered, and future directions suggested.
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Affiliation(s)
- Mads C. J. Barloese
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark
- Department of Clinical Physiology and Nuclear Imaging, Center for Functional and Diagnostic Imaging, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark
| | - Christian Bauer
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark
- Radiography, Department of Technology, University College Copenhagen, Copenhagen, Denmark
| | - Esben Thade Petersen
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark
- Center for Magnetic Resonance, Department of Electrical Engineering, Technical University of Denmark, Lyngby, Denmark
| | | | - Sten Madsbad
- Department of Endocrinology, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Hartwig Roman Siebner
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Neurology, Copenhagen University Hospital - Bispebjerg and Fredriksberg, Copenhagen, Denmark
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Marzolini S, Wu C, Hussein R, Xiong LY, Kangatharan S, Peni A, Cooper CR, Lau KS, Nzodjou Makhdoom G, Pakosh M, Zaban SA, Nguyen MM, Banihashemi MA, Swardfager W. Associations Between Time After Stroke and Exercise Training Outcomes: A Meta-Regression Analysis. J Am Heart Assoc 2021; 10:e022588. [PMID: 34913357 PMCID: PMC9075264 DOI: 10.1161/jaha.121.022588] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Background Knowledge gaps exist regarding the effect of time elapsed after stroke on the effectiveness of exercise training interventions, offering incomplete guidance to clinicians. Methods and Results To determine the associations between time after stroke and 6-minute walk distance, 10-meter walk time, cardiorespiratory fitness and balance (Berg Balance Scale score [BBS]) in exercise training interventions, relevant studies in post-stroke populations were identified by systematic review. Time after stroke as continuous or dichotomized (≤3 months versus >3 months, and ≤6 months versus >6 months) variables and weighted mean differences in postintervention outcomes were examined in meta-regression analyses adjusted for study baseline mean values (pre-post comparisons) or baseline mean values and baseline control-intervention differences (controlled comparisons). Secondary models were adjusted additionally for mean age, sex, and aerobic exercise intensity, dose, and modality. We included 148 studies. Earlier exercise training initiation was associated with larger pre-post differences in mobility; studies initiated ≤3 months versus >3 months after stroke were associated with larger differences (weighted mean differences [95% confidence interval]) in 6-minute walk distance (36.3 meters; 95% CI, 14.2-58.5), comfortable 10-meter walk time (0.13 m/s; 95% CI, 0.06-0.19) and fast 10-meter walk time (0.16 m/s; 95% CI, 0.03-0.3), in fully adjusted models. Initiation ≤3 months versus >3 months was not associated with cardiorespiratory fitness but was associated with a higher but not clinically important Berg Balance Scale score difference (2.9 points; 95% CI, 0.41-5.5). In exercise training versus control studies, initiation ≤3 months was associated with a greater difference in only postintervention 6-minute walk distance (baseline-adjusted 27.3 meters; 95% CI, 6.1-48.5; fully adjusted, 24.9 meters; 95% CI, 0.82-49.1; a similar association was seen for ≤6 months versus >6 months after stroke (fully adjusted, 26.6 meters; 95% CI, 2.6-50.6). Conclusions There may be a clinically meaningful benefit to mobility outcomes when exercise is initiated within 3 months and up to 6 months after stroke.
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Affiliation(s)
- Susan Marzolini
- KITE Research Institute, Toronto Rehabilitation Institute ‐ University Health NetworkTorontoONCanada
- Healthy Living for Pandemic Event Protection (HL–PIVOT) NetworkTorontoONCanada
- Rehabilitation Sciences InstituteUniversity of TorontoONCanada
- Faculty of Kinesiology and Physical EducationUniversity of TorontoONCanada
| | - Che‐Yuan Wu
- Department of Pharmacology and ToxicologyUniversity of TorontoONCanada
- Hurvitz Brain Sciences ProgramSunnybrook Research InstituteTorontoONCanada
| | | | - Lisa Y. Xiong
- Department of Pharmacology and ToxicologyUniversity of TorontoONCanada
- Hurvitz Brain Sciences ProgramSunnybrook Research InstituteTorontoONCanada
| | - Suban Kangatharan
- KITE Research Institute, Toronto Rehabilitation Institute ‐ University Health NetworkTorontoONCanada
| | - Ardit Peni
- KITE Research Institute, Toronto Rehabilitation Institute ‐ University Health NetworkTorontoONCanada
| | | | - Kylie S.K. Lau
- Department of Human BiologyUniversity of TorontoONCanada
| | | | - Maureen Pakosh
- Library & Information ServicesUniversity Health NetworkToronto Rehabilitation InstituteTorontoONCanada
| | - Stephanie A. Zaban
- Faculty of Kinesiology and Physical EducationUniversity of TorontoONCanada
| | - Michelle M. Nguyen
- Department of Pharmacology and ToxicologyUniversity of TorontoONCanada
- Hurvitz Brain Sciences ProgramSunnybrook Research InstituteTorontoONCanada
| | - Mohammad Amin Banihashemi
- Hurvitz Brain Sciences ProgramSunnybrook Research InstituteTorontoONCanada
- Institute of Medical ScienceUniversity of TorontoTorontoONCanada
| | - Walter Swardfager
- KITE Research Institute, Toronto Rehabilitation Institute ‐ University Health NetworkTorontoONCanada
- Department of Pharmacology and ToxicologyUniversity of TorontoONCanada
- Hurvitz Brain Sciences ProgramSunnybrook Research InstituteTorontoONCanada
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Yen HC, Jeng JS, Cheng CH, Pan GS, Chen WS. Effects of early mobilization on short-term blood pressure variability in acute intracerebral hemorrhage patients: A protocol for randomized controlled non-inferiority trial. Medicine (Baltimore) 2021; 100:e26128. [PMID: 34032760 PMCID: PMC8154506 DOI: 10.1097/md.0000000000026128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 03/14/2021] [Accepted: 05/07/2021] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Early out-of-bed mobilization may improve acute post-intracerebral hemorrhage (ICH) outcomes, but hemodynamic instability may be a concern. Some recent studies have showed that an increase in mean systolic blood pressure (SBP) and high blood pressure variability (BPV), high standard deviation of SBP, may lead to negative ICH outcomes. Therefore, we investigated the impact of an early mobilization (EM) protocol on mean SBP and BPV during the acute phase. METHODS The study was an assessor-blinded, randomized controlled non-inferiority study. The participants were in An Early Mobilization for Acute Cerebral Hemorrhage trial and were randomly assigned to undergo EM or a standard early rehabilitation (SER) protocol within 24 to 72 hour after ICH onset at the stroke center. The EM and SER groups each had 30 patients. 24-measurement SBP were recorded on days 2 and 3 after onset, and SBP were recorded three times daily and during rehabilitation on days 4 through 7. The two groups' mean SBP and BPV under three different time frames (days 2 and 3 during the acute phase, and days 4 through 7 during the late acute phase) were calculated and compared. RESULTS At baseline, the two groups' results were similar, with the exception being that the mean time to first out-of-bed mobilization after symptom onset was 51.60 hours (SD 14.15) and 135.02 hours (SD 33.05) for the EM group and SER group, respectively (P < .001). There were no significant differences in mean SBP and BPV during the acute and late acute phase between the two groups for the three analyses (days 2, 3, and 4 through 7) (P > .05). CONCLUSIONS It is safe to implement the EM protocol within 24 to 72 hour of onset for mild-moderate ICH patients during the acute phase.
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Affiliation(s)
- Hsiao-Ching Yen
- Division of Physical Therapy, Department of Physical Medicine and Rehabilitation
| | | | | | - Guan-Shuo Pan
- Division of Physical Therapy, Department of Physical Medicine and Rehabilitation
| | - Wen-Shiang Chen
- Department of Physical Medicine and Rehabilitation, National Taiwan University Hospital, Taipei, Taiwan
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Nogueira RC, Beishon L, Bor-Seng-Shu E, Panerai RB, Robinson TG. Cerebral Autoregulation in Ischemic Stroke: From Pathophysiology to Clinical Concepts. Brain Sci 2021; 11:511. [PMID: 33923721 PMCID: PMC8073938 DOI: 10.3390/brainsci11040511] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 04/02/2021] [Accepted: 04/09/2021] [Indexed: 11/17/2022] Open
Abstract
Ischemic stroke (IS) is one of the most impacting diseases in the world. In the last decades, new therapies have been introduced to improve outcomes after IS, most of them aiming for recanalization of the occluded vessel. However, despite this advance, there are still a large number of patients that remain disabled. One interesting possible therapeutic approach would be interventions guided by cerebral hemodynamic parameters such as dynamic cerebral autoregulation (dCA). Supportive hemodynamic therapies aiming to optimize perfusion in the ischemic area could protect the brain and may even extend the therapeutic window for reperfusion therapies. However, the knowledge of how to implement these therapies in the complex pathophysiology of brain ischemia is challenging and still not fully understood. This comprehensive review will focus on the state of the art in this promising area with emphasis on the following aspects: (1) pathophysiology of CA in the ischemic process; (2) methodology used to evaluate CA in IS; (3) CA studies in IS patients; (4) potential non-reperfusion therapies for IS patients based on the CA concept; and (5) the impact of common IS-associated comorbidities and phenotype on CA status. The review also points to the gaps existing in the current research to be further explored in future trials.
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Affiliation(s)
- Ricardo C. Nogueira
- Neurology Department, School of Medicine, Hospital das Clinicas, University of São Paulo, São Paulo 01246-904, Brazil;
- Department of Neurology, Hospital Nove de Julho, São Paulo 01409-002, Brazil
| | - Lucy Beishon
- Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester LE2 7LX, UK; (L.B.); (R.B.P.); (T.G.R.)
| | - Edson Bor-Seng-Shu
- Neurology Department, School of Medicine, Hospital das Clinicas, University of São Paulo, São Paulo 01246-904, Brazil;
| | - Ronney B. Panerai
- Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester LE2 7LX, UK; (L.B.); (R.B.P.); (T.G.R.)
- National Institute for Health Research (NIHR) Leicester Biomedical Research Centre, University of Leicester, Leicester LE5 4PW, UK
| | - Thompson G. Robinson
- Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester LE2 7LX, UK; (L.B.); (R.B.P.); (T.G.R.)
- National Institute for Health Research (NIHR) Leicester Biomedical Research Centre, University of Leicester, Leicester LE5 4PW, UK
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Guo Z, Wu X, Fan W. Clarifying the effects of diabetes on the cerebral circulation: Implications for stroke recovery and beyond. Brain Res Bull 2021; 171:67-74. [PMID: 33662495 DOI: 10.1016/j.brainresbull.2021.02.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 02/21/2021] [Accepted: 02/26/2021] [Indexed: 02/07/2023]
Abstract
Given the sheer increased number of victims per year and the availability of only one effective treatment, acute ischemic stroke (AIS) remains to be one of the most under-treated serious diseases. Diabetes not only increases the incidence of ischemic stroke, but amplifies the ischemic damage, upon which if patients with diabetes suffer from stroke, he/she will confront increased risks of long-term functional deficits. The grim reality makes it a pressing need to intensify efforts at the basic science level to understand how diabetes impairs stroke recovery. This review retrospects the clinical and experimental studies in order to elucidate the detrimental effect of diabetes on cerebrovascular circulation including the major arteries/arterioles, collateral circulation, and neovascularization to shed light on further exploration of novel strategies for cerebral circulation protection before and after AIS in patients with diabetes.
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Affiliation(s)
- Zhihui Guo
- Department of Neurology, Zhongshan Hospital, Fudan University, 200032, Shanghai, China
| | - Xuqing Wu
- Department of Neurology, Zhongshan Hospital, Fudan University, 200032, Shanghai, China
| | - Wei Fan
- Department of Neurology, Zhongshan Hospital, Fudan University, 200032, Shanghai, China.
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Delay of cerebral autoregulation in traumatic brain injury patients. Clin Neurol Neurosurg 2021; 202:106478. [PMID: 33454499 DOI: 10.1016/j.clineuro.2021.106478] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 01/04/2021] [Accepted: 01/05/2021] [Indexed: 11/22/2022]
Abstract
INTRODUCTION Adequate cerebral perfusion prevents secondary insult after traumatic brain injury (TBI). Cerebral autoregulation (CAR) keeps cerebral blood flow (CBF) constant when arterial blood pressure (ABP) changes. Aim of the study was to evaluate the existence of delayed CAR in TBI patients and its possible association with outcome. METHODS We retrospectively analysed TBI patients. Flow velocity (FV) in middle cerebral artery, invasive intra-cranial pressure (ICP) and ABP were recorded. Cerebral perfusion pressure (CPP) was calculated as ABP - ICP. Mean flow index (Mx) > 0.3 defined altered CAR. Samples from patients with altered CAR were further analysed: FV signal was shifted backward relative to CPP; Mx was calculated after each shift (MxD). Mx > 0.3 plus MxD ≤ 0.3 defined delayed CAR. Favourable outcome (FO) at 6 months was defined as Glasgow Outcome Scale 4-5. RESULTS 154 patients were included. GCS was 6 [4-9], ICP was 14 [9-20] mmHg. Data on 6 months outcome were available for 131 patients: 104/131 patients (79 %) were alive; GOS was 4 [3-5]; 70/131 (53 %) had FO. Mx was 0.07 [-0.19 to 0.28] overall. Mx was lower in patients with FO compared others (0.00 [-0.21 to 0.20] vs 0.17 [-0.12 to 0.37], p = 0.02). 118 (77 %) patients had intact CAR and 36 (23 %) patients had altered CAR; 23 patients - 15 % of the general cohort and 64 % of patients with altered CAR - had delayed CAR. Delay in the autoregulatory response was 2 [1-4] seconds. 80/98 (82 %) of patients with intact CAR survived, compared to 16/21 (76 %) with delayed and 8/12 (67 %) with altered CAR (p = 0.20). 80/98 (58 %) patients with intact, 10/21 (48 %) patients with delayed and 3/12 (25 %) patients with altered CAR had FO (p = 0.03). CONCLUSION A subgroup of TBI patients with delayed CAR was identified. Delayed CAR was associated with better neurological outcome than altered CAR.
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Hemodynamics in acute stroke: Cerebral and cardiac complications. HANDBOOK OF CLINICAL NEUROLOGY 2021; 177:295-317. [PMID: 33632449 DOI: 10.1016/b978-0-12-819814-8.00015-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Hemodynamics is the study of blood flow, where parameters have been defined to quantify blood flow and the relationship with systemic circulatory changes. Understanding these perfusion parameters, the relationship between different blood flow variables and the implications for ischemic injury are outlined in the ensuing discussion. This chapter focuses on the hemodynamic changes that occur in ischemic stroke, and their contribution to ischemic stroke pathophysiology. We discuss the interaction between cardiovascular response and hemodynamic changes in stroke. Studying hemodynamic changes has a key role in stroke prevention, therapeutic implications and prognostic importance in acute ischemic stroke: preexisting hemodynamic and autoregulatory impairments predict the occurrence of stroke. Hemodynamic failure predisposes to the formation of thromboemboli and accelerates infarction due to impairing compensatory mechanisms. In ischemic stroke involving occlusion of a large vessel, persistent collateral circulation leads to preservation of ischemic penumbra and therefore justifying endovascular thrombectomy. Following thrombectomy, impaired autoregulation may lead to reperfusion injury and hemorrhage.
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Mahinrad S, Shownkeen M, Sedaghat S, Yaffe K, Hausdorff JM, Lloyd-Jones DM, Gorelick PB, Sorond FA. Vascular health across young adulthood and midlife cerebral autoregulation, gait, and cognition. Alzheimers Dement 2020; 17:745-754. [PMID: 33283978 DOI: 10.1002/alz.12246] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 10/23/2020] [Accepted: 11/01/2020] [Indexed: 11/10/2022]
Abstract
INTRODUCTION To test the association of vascular health (VH) across young adulthood with midlife dynamic cerebral autoregulation (dCA), gait, and cognition; and to test whether dCA is a modifying factor. METHODS We studied 196 participants from the Coronary Artery Risk Development in Young Adults cohort who were followed over 30 years. VH was assessed at each visit according to American Heart Association recommendations. At year 30, dCA was measured using transcranial Doppler ultrasound and several gait and cognitive domains were assessed. RESULTS Worse VH from baseline through year 7, but not at year 30, was associated with less efficient dCA (all P < .05). Worse VH at all visits was associated with slower gait speed, and at year 7 with worse executive and global cognition (all P < .05). The association of baseline VH and midlife gait, but not cognition, was moderated by dCA (interaction P < .05). CONCLUSIONS VH as early as young adulthood may influence midlife brain health, and dCA may modify this relationship.
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Affiliation(s)
- Simin Mahinrad
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Meghana Shownkeen
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA.,College of Medicine, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Sanaz Sedaghat
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA.,Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Kristine Yaffe
- Department of Psychiatry, Neurology and Epidemiology, University of California San Francisco, San Francisco, California, USA
| | - Jeffrey M Hausdorff
- Center for the Study of Movement Cognition and Mobility, Neurological Institute, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.,Sagol School of Neuroscience and Department of Physical Therapy, Tel Aviv University, Tel Aviv, Israel.,Rush Alzheimer's Disease Center and Department of Orthopedic Surgery, Rush University, Chicago, Illinois, USA
| | - Donald M Lloyd-Jones
- Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Philip B Gorelick
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Farzaneh A Sorond
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
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Mahinrad S, Sabayan B, Garner CR, Lloyd-Jones DM, Sorond FA. N-Terminal Pro Brain, N-Terminal Pro Atrial Natriuretic Peptides, and Dynamic Cerebral Autoregulation. J Am Heart Assoc 2020; 9:e018203. [PMID: 33059537 PMCID: PMC7763392 DOI: 10.1161/jaha.120.018203] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Background Elevated natriuretic peptides (NP) are associated with adverse cerebrovascular conditions including stroke, cerebral small vessel disease, and dementia. However, the mechanisms underlying these associations remain unclear. In this study, we examined the relationship of NT‐proBNP (N‐terminal pro brain NP) and NT‐proANP (N‐terminal pro atrial NP) with cerebrovascular function, measured by cerebral autoregulation. Methods and Results We included 154 participants (mean age 56±4 years old) from the CARDIA (Coronary Artery Risk Development in Young Adults) cohort. NT‐proBNP and NT‐proANP were measured in blood samples from the year 25 examination using electrochemiluminescence Immunoassay and enzyme‐linked immunoassay, respectively. Dynamic cerebral autoregulation (dCA) was assessed at the year 30 examination by transcranial Doppler ultrasound, using transfer function analysis (phase and gain) of spontaneous blood pressure and flow velocity oscillations, where lower phase and higher gain reflect less efficient cerebral autoregulation. We used multivariable linear regression models adjusted for demographics, vascular risk factors, and history of kidney and cardiac diseases. Higher NT‐proBNP levels at year 25 were associated with lower phase (β [95% CI]=−5.30 lower degrees of phase [−10.05 to −0.54]) and higher gain (β [95% CI]=0.06 higher cm/s per mm Hg of gain [0.004–0.12]) at year 30. Similarly, higher NT‐proANP levels were associated with lower phase (β [95% CI]=−9.08 lower degrees of phase [−16.46 to −1.70]). Conclusions Higher circulating levels of NT‐proBNP and NT‐proANP are associated with less efficient dCA 5 years later. These findings link circulating NP to cerebral autoregulation and may be one mechanism tying NP to adverse cerebrovascular outcomes.
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Affiliation(s)
- Simin Mahinrad
- Department of Neurology Northwestern University Feinberg School of Medicine Chicago IL
| | - Behnam Sabayan
- Department of Neurology Northwestern University Feinberg School of Medicine Chicago IL
| | - Chaney R Garner
- Department of Neurology Northwestern University Feinberg School of Medicine Chicago IL
| | - Donald M Lloyd-Jones
- Department of Preventive Medicine Northwestern University Feinberg School of Medicine Chicago IL
| | - Farzaneh A Sorond
- Department of Neurology Northwestern University Feinberg School of Medicine Chicago IL
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Bahrani AA, Kong W, Shang Y, Huang C, Smith CD, Powell DK, Jiang Y, Rayapati AO, Jicha GA, Yu G. Diffuse optical assessment of cerebral-autoregulation in older adults stratified by cerebrovascular risk. JOURNAL OF BIOPHOTONICS 2020; 13:e202000073. [PMID: 32533642 PMCID: PMC8824485 DOI: 10.1002/jbio.202000073] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 05/06/2020] [Accepted: 06/09/2020] [Indexed: 05/04/2023]
Abstract
Diagnosis of cerebrovascular disease (CVD) at early stages is essential for preventing sequential complications. CVD is often associated with abnormal cerebral microvasculature, which may impact cerebral-autoregulation (CA). A novel hybrid near-infrared diffuse optical instrument and a finger plethysmograph were used to simultaneously detect low-frequency oscillations (LFOs) of cerebral blood flow (CBF), oxy-hemoglobin concentration ([HbO2 ]), deoxy-hemoglobin concentration ([Hb]) and mean arterial pressure (MAP) in older adults before, during and after 70° head-up-tilting (HUT). The participants with valid data were divided based on Framingham risk score (FRS, 1-30 points) into low-risk (FRS ≤15, n = 13) and high-risk (FRS >15, n = 11) groups for developing CVD. The LFO gains were determined by transfer function analyses with MAP as the input, and CBF, [HbO2 ] and [Hb] as the outputs (CA ∝ 1/Gain). At resting-baseline, LFO gains in the high-risk group were relatively lower compared to the low-risk group. The lower baseline gains in the high-risk group may attribute to compensatory mechanisms to maintain stronger steady-state CAs. However, HUT resulted in smaller gain reductions in the high-risk group compared to the low-risk group, suggesting weaker dynamic CAs. LFO gains are potentially valuable biomarkers for early detection of CVD based on associations with CAs.
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Affiliation(s)
- Ahmed A. Bahrani
- Department of Biomedical Engineering, University of Kentucky, Lexington, Kentucky
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky
- Biomedical Engineering Department, Al-Khwarizmi College of Engineering, University of Baghdad, Baghdad, Iraq
| | - Weikai Kong
- Department of Biomedical Engineering, University of Kentucky, Lexington, Kentucky
| | - Yu Shang
- Shanxi Provincial Key Laboratory for Biomedical Imaging and Big Data, North University of China, Shanxi, China
| | - Chong Huang
- Department of Biomedical Engineering, University of Kentucky, Lexington, Kentucky
| | - Charles D. Smith
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky
- Magnetic Resonance Imaging and Spectroscopy Center (MRISC), University of Kentucky, Lexington, Kentucky
- Department of Neurology, University of Kentucky, Lexington, Kentucky
| | - David K. Powell
- Magnetic Resonance Imaging and Spectroscopy Center (MRISC), University of Kentucky, Lexington, Kentucky
- Neuroscience Department, University of Kentucky, Lexington, Kentucky
| | - Yang Jiang
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky
- Magnetic Resonance Imaging and Spectroscopy Center (MRISC), University of Kentucky, Lexington, Kentucky
- Department of Behavioral Science, University of Kentucky, Lexington, Kentucky
| | - Abner O. Rayapati
- Department of Psychiatry, University of Kentucky, Lexington, Kentucky
| | - Gregory A. Jicha
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky
- Magnetic Resonance Imaging and Spectroscopy Center (MRISC), University of Kentucky, Lexington, Kentucky
- Department of Neurology, University of Kentucky, Lexington, Kentucky
| | - Guoqiang Yu
- Department of Biomedical Engineering, University of Kentucky, Lexington, Kentucky
- Correspondence: Guoqiang Yu, Department of Biomedical Engineering, University of Kentucky, Lexington, KY 40506,
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Muhire G, Iulita MF, Vallerand D, Youwakim J, Gratuze M, Petry FR, Planel E, Ferland G, Girouard H. Arterial Stiffness Due to Carotid Calcification Disrupts Cerebral Blood Flow Regulation and Leads to Cognitive Deficits. J Am Heart Assoc 2020; 8:e011630. [PMID: 31057061 PMCID: PMC6512142 DOI: 10.1161/jaha.118.011630] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Background Arterial stiffness is associated with cognitive decline and dementia; however, the precise mechanisms by which it affects the brain remain unclear. Methods and Results Using a mouse model based on carotid calcification this study characterized mechanisms that could contribute to brain degeneration due to arterial stiffness. At 2 weeks postcalcification, carotid stiffness attenuated resting cerebral blood flow in several brain regions including the perirhinal/entorhinal cortex, hippocampus, and thalamus, determined by autoradiography (P<0.05). Carotid calcification impaired cerebral autoregulation and diminished cerebral blood flow responses to neuronal activity and to acetylcholine, examined by laser Doppler flowmetry (P<0.05, P<0.01). Carotid stiffness significantly affected spatial memory at 3 weeks (P<0.05), but not at 2 weeks, suggesting that cerebrovascular impairments precede cognitive dysfunction. In line with the endothelial deficits, carotid stiffness led to increased blood‐brain barrier permeability in the hippocampus (P<0.01). This region also exhibited reductions in vessel number containing collagen IV (P<0.01), as did the somatosensory cortex (P<0.05). No evidence of cerebral microhemorrhages was present. Carotid stiffness did not affect the production of mouse amyloid‐β (Aβ) or tau phosphorylation, although it led to a modest increase in the Aβ40/Aβ42 ratio in frontal cortex (P<0.01). Conclusions These findings suggest that carotid stiffness alters brain microcirculation and increases blood‐brain barrier permeability associated with cognitive impairments. Therefore, arterial stiffness should be considered a relevant target to protect the brain and prevent cognitive dysfunctions.
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Affiliation(s)
- Gervais Muhire
- 1 Département de Pharmacologie et Physiologie Université de Montréal Québec Canada
| | - M Florencia Iulita
- 2 Groupe de Recherche sur le Système Nerveux Central Université de Montréal Québec Canada.,3 Département de Neurosciences Université de Montréal Québec Canada
| | - Diane Vallerand
- 1 Département de Pharmacologie et Physiologie Université de Montréal Québec Canada
| | - Jessica Youwakim
- 1 Département de Pharmacologie et Physiologie Université de Montréal Québec Canada
| | - Maud Gratuze
- 4 Département de Psychiatrie et Neurosciences Université Laval Québec Québec Canada
| | - Franck R Petry
- 4 Département de Psychiatrie et Neurosciences Université Laval Québec Québec Canada
| | - Emmanuel Planel
- 4 Département de Psychiatrie et Neurosciences Université Laval Québec Québec Canada.,5 Centre de Recherche du CHU de Québec Québec Canada
| | - Guylaine Ferland
- 6 Département de Nutrition Université de Montréal Québec Canada.,7 Centre de Recherche de l'Institut de Cardiologie de Montréal Montréal Québec Canada
| | - Hélène Girouard
- 1 Département de Pharmacologie et Physiologie Université de Montréal Québec Canada.,2 Groupe de Recherche sur le Système Nerveux Central Université de Montréal Québec Canada.,8 Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal Montréal Québec Canada
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van Campen C(LM, Rowe PC, Visser FC. Cerebral Blood Flow Is Reduced in Severe Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Patients During Mild Orthostatic Stress Testing: An Exploratory Study at 20 Degrees of Head-Up Tilt Testing. Healthcare (Basel) 2020; 8:healthcare8020169. [PMID: 32545797 PMCID: PMC7349207 DOI: 10.3390/healthcare8020169] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 06/01/2020] [Accepted: 06/10/2020] [Indexed: 12/14/2022] Open
Abstract
Introduction: In a study of 429 adults with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), we demonstrated that 86% had symptoms of orthostatic intolerance in daily life. Using extracranial Doppler measurements of the internal carotid and vertebral arteries during a 30-min head-up tilt to 70 degrees, 90% had an abnormal reduction in cerebral blood flow (CBF). A standard head-up tilt test of this duration might not be tolerated by the most severely affected bed-ridden ME/CFS patients. This study examined whether a shorter 15-min test at a lower 20 degree tilt angle would be sufficient to provoke reductions in cerebral blood flow in severe ME/CFS patients. Methods and results: Nineteen severe ME/CFS patients with orthostatic intolerance complaints in daily life were studied: 18 females. The mean (SD) age was 35(14) years, body surface area (BSA) was 1.8(0.2) m2 and BMI was 24.0(5.4) kg/m2. The median disease duration was 14 (IQR 5–18) years. Heart rate increased, and stroke volume index and end-tidal CO2 decreased significantly during the test (p ranging from <0.001 to <0.0001). The cardiac index decreased by 26(7)%: p < 0.0001. CBF decreased from 617(72) to 452(63) mL/min, a 27(5)% decline. All 19 severely affected ME/CFS patients met the criteria for an abnormal CBF reduction. Conclusions: Using a less demanding 20 degree tilt test for 15 min in severe ME/CFS patients resulted in a mean CBF decline of 27%. This is comparable to the mean 26% decline previously noted in less severely affected patients studied during a 30-min 70 degree head-up tilt. These observations have implications for the evaluation and treatment of severely affected individuals with ME/CFS.
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Affiliation(s)
| | - Peter C. Rowe
- Department of Paediatrics, John Hopkins University School of Medicine, Baltimore, MD 21205, USA;
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Abstract
PURPOSE To review the recent developments on the effect of chronic high mean arterial blood pressure (MAP) on cerebral blood flow (CBF) autoregulation and supporting the notion that CBF autoregulation impairment has connection with chronic cerebral diseases. Method: A narrative review of all the relevant papers known to the authors was conducted. Results: Our understanding of the connection between cerebral perfusion impairment and chronic high MAP and cerebral disease is rapidly evolving, from cerebral perfusion impairment being the result of cerebral diseases to being the cause of cerebral diseases. We now better understand the intertwined impact of hypertension and Alzheimer's disease (AD) on cerebrovascular sensory elements and recognize cerebrovascular elements that are more vulnerable to these diseases. Conclusion: We conclude with the suggestion that the sensory elements pathology plays important roles in intertwined mechanisms of chronic high MAP and AD that impact cerebral perfusion.
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Affiliation(s)
- Noushin Yazdani
- College of Public Health, University of South Florida , Tampa, FL, USA
| | - Mark S Kindy
- Department of Pharmaceutical Sciences, College of Pharmacy, University of South Florida , Tampa, FL, USA.,Biomedical Research, James A. Haley VA Medical Center , Tampa, FL, USA
| | - Saeid Taheri
- Department of Pharmaceutical Sciences, College of Pharmacy, University of South Florida , Tampa, FL, USA.,Byrd Neuroscience Institute, University of South Florida , Tampa, FL, USA
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van Campen C(LM, Verheugt FW, Rowe PC, Visser FC. Cerebral blood flow is reduced in ME/CFS during head-up tilt testing even in the absence of hypotension or tachycardia: A quantitative, controlled study using Doppler echography. Clin Neurophysiol Pract 2020; 5:50-58. [PMID: 32140630 PMCID: PMC7044650 DOI: 10.1016/j.cnp.2020.01.003] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 12/05/2019] [Accepted: 01/02/2020] [Indexed: 02/06/2023] Open
Abstract
OBJECTIVE The underlying hypothesis in orthostatic intolerance (OI) syndromes is that symptoms are associated with cerebral blood flow (CBF) reduction. Indirect CBF measurements (transcranial Doppler flow velocities), provide inconsistent support of this hypothesis. The aim of the study was to measure CBF during a 30 min head-up tilt test (HUT), using Doppler flow imaging of carotid and vertebral arteries, in individuals with chronic fatigue syndrome/myalgic encephalomyelitis (ME/CFS), a condition with a high prevalence of OI. METHODS 429 ME/CFS patients were studied: 247 had a normal heart rate (HR) and blood pressure (BP) response to HUT, 62 had delayed orthostatic hypotension (dOH), and 120 had postural orthostatic tachycardia syndrome (POTS). We also studied 44 healthy controls (HC). CBF measurements were made at mid-tilt and end-tilt. Before mid-tilt, we administered a verbal questionnaire to ascertain for 15 OI symptoms. RESULTS End-tilt CBF reduction was 7% in HC versus 26% in the overall ME/CFS group, 24% in patients with a normal HR/BP response, 28% in those with dOH, and 29% in POTS patients (all P < .0005). Using a lower limit of normal of 2SD of CBF reduction in HC (13% reduction), 82% of patients with normal HR/BP response, 98% with dOH and 100% with POTS showed an abnormal CBF reduction. There was a linear correlation of summed OI symptoms with the degree of CBF reduction at mid-tilt (P < .0005). CONCLUSIONS During HUT, extracranial Doppler measurements demonstrate that CBF is reduced in ME/CFS patients with POTS, dOH, and even in those without HR/BP abnormalities. SIGNIFICANCE This study shows that orthostatic intolerance symptoms are related to CBF reduction, and that the majority of ME/CFS patients (90%) show an abnormal cerebral flow reduction during orthostatic stress testing. This may have implications for the diagnosis and treatment of ME/CFS patients.
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Affiliation(s)
| | - Freek W.A. Verheugt
- Department of Cardiology, Onze Lieve Vrouwe Gasthuis (OLVG), Oosterpark 9, 1091 AC Amsterdam, The Netherlands
| | - Peter C. Rowe
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Frans C. Visser
- Stichting CardioZorg, Planetenweg 5, 2132 HN Hoofddorp, The Netherlands
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Does uncontrolled diabetes mellitus affect cerebral hemodynamics in heart surgery? TURK GOGUS KALP DAMAR CERRAHISI DERGISI-TURKISH JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY 2020; 28:84-91. [PMID: 32175147 DOI: 10.5606/tgkdc.dergisi.2020.18685] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Accepted: 11/20/2019] [Indexed: 01/08/2023]
Abstract
Background In this study, we aimed to investigate the effects of poor blood glucose control on the intraoperative cerebral system in patients undergoing coronary artery bypass grafting using various neuromonitors. Methods Between January 2011 and December 2011, a total of 40 adult patients (31 males, 9 females; mean age 58.8±9.2 years; range, 38 to 78 years) who were scheduled for elective coronary artery bypass grafting were included in the study. The patients were divided into four groups according to hemoglobin A1c levels as follows: Group 1 including non-diabetic controls (n=11); Group 2 including those with a hemoglobin A1c value of <7% (n=10); Group 3 including those with a hemoglobin A1c value of 7 to 10% (n=11); and Group 4 including those with a hemoglobin A1c value of ≥10% (n=8). Cerebral monitoring was performed with near-infrared spectroscopy and transcranial Doppler. Measurement periods were defined as follows: Before anesthesia induction (period 1), 10 min after anesthesia induction (period 2), during cannulation (period 3), 10 min after cardiopulmonary bypass (period 4), at 32°C temperature during cardiopulmonary bypass (period 5), at 36°C temperature during cardiopulmonary bypass (period 6), and at the end of the operation (period 7). Results There was a significant difference in the near-infrared spectroscopy values in the cannulation period for both right (p<0.001) and left (p=0.002) sides and the mean transcranial Doppler flow velocity (p=0.002) in Group 4, compared to Group 1. The heart rate was found to be significantly lower in Group 4 in the cannulation period. The near-infrared spectroscopy values and transcranial Doppler blood flow velocity decreased in Group 4 in all measurement periods. Conclusion The results of our study show that, in patients with severe diabetes undergoing open heart surgery, heart rate decreases in the cannulation period due to possible autonomic neuropathy, and cerebral blood flow and oxygenation decrease. For these patients, particularly in the cannulation period, perfusion of both cerebral and other organs should be closely monitored and necessary interventions should be performed.
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Marzolini S, Robertson AD, Oh P, Goodman JM, Corbett D, Du X, MacIntosh BJ. Aerobic Training and Mobilization Early Post-stroke: Cautions and Considerations. Front Neurol 2019; 10:1187. [PMID: 31803129 PMCID: PMC6872678 DOI: 10.3389/fneur.2019.01187] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Accepted: 10/25/2019] [Indexed: 12/14/2022] Open
Abstract
Knowledge gaps exist in how we implement aerobic exercise programs during the early phases post-stroke. Therefore, the objective of this review was to provide evidence-based guidelines for pre-participation screening, mobilization, and aerobic exercise training in the hyper-acute and acute phases post-stroke. In reviewing the literature to determine safe timelines of when to initiate exercise and mobilization we considered the following factors: arterial blood pressure dysregulation, cardiac complications, blood-brain barrier disruption, hemorrhagic stroke transformation, and ischemic penumbra viability. These stroke-related impairments could intensify with inappropriate mobilization/aerobic exercise, hence we deemed the integrity of cerebral autoregulation to be an essential physiological consideration to protect the brain when progressing exercise intensity. Pre-participation screening criteria are proposed and countermeasures to protect the brain from potentially adverse circulatory effects before, during, and following mobilization/exercise sessions are introduced. For example, prolonged periods of standing and static postures before and after mobilization/aerobic exercise may elicit blood pooling and/or trigger coagulation cascades and/or cerebral hypoperfusion. Countermeasures such as avoiding prolonged standing or incorporating periodic lower limb movement to activate the venous muscle pump could counteract blood pooling after an exercise session, minimize activation of the coagulation cascade, and mitigate potential cerebral hypoperfusion. We discuss patient safety in light of the complex nature of stroke presentations (i.e., type, severity, and etiology), medical history, comorbidities such as diabetes, cardiac manifestations, medications, and complications such as anemia and dehydration. The guidelines are easily incorporated into the care model, are low-risk, and use minimal resources. These and other strategies represent opportunities for improving the safety of the activity regimen offered to those in the early phases post-stroke. The timeline for initiating and progressing exercise/mobilization parameters are contingent on recovery stages both from neurobiological and cardiovascular perspectives, which to this point have not been specifically considered in practice. This review includes tailored exercise and mobilization prescription strategies and precautions that are not resource intensive and prioritize safety in stroke recovery.
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Affiliation(s)
- Susan Marzolini
- KITE, Toronto Rehab-University Health Network, Toronto, ON, Canada
- Department of Exercise Sciences, Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, ON, Canada
- Canadian Partnership for Stroke Recovery, Toronto, ON, Canada
| | - Andrew D. Robertson
- Schlegel-University of Waterloo Research Institute for Aging, University of Waterloo, Waterloo, ON, Canada
- Department of Kinesiology, University of Waterloo, Waterloo, ON, Canada
| | - Paul Oh
- KITE, Toronto Rehab-University Health Network, Toronto, ON, Canada
- Department of Exercise Sciences, Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, ON, Canada
- Canadian Partnership for Stroke Recovery, Toronto, ON, Canada
| | - Jack M. Goodman
- KITE, Toronto Rehab-University Health Network, Toronto, ON, Canada
- Department of Exercise Sciences, Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, ON, Canada
| | - Dale Corbett
- Canadian Partnership for Stroke Recovery, Toronto, ON, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Xiaowei Du
- KITE, Toronto Rehab-University Health Network, Toronto, ON, Canada
- School of Kinesiology and Health Studies, Queen's University, Kingston, ON, Canada
| | - Bradley J. MacIntosh
- Canadian Partnership for Stroke Recovery, Toronto, ON, Canada
- Sunnybrook Health Sciences Center, Toronto, ON, Canada
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Untreated Relative Hypotension Measured as Perfusion Pressure Deficit During Management of Shock and New-Onset Acute Kidney Injury-A Literature Review. Shock 2019; 49:497-507. [PMID: 29040214 DOI: 10.1097/shk.0000000000001033] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Maintaining an optimal blood pressure (BP) during shock is a fundamental tenet of critical care. Optimal BP targets may be different for different patients. In current practice, too often, uniform BP targets are pursued which may result in inadvertently accepting a degree of untreated relative hypotension, i.e., the deficit between patients' usual premorbid basal BP and the achieved BP, during vasopressor support. Relative hypotension is a common but an under-recognized and an under-treated sign among patients with potential shock state. From a physiological perspective, any relative reduction in the net perfusion pressure across an organ (e.g., renal) vasculature has a potential to overwhelm autoregulatory mechanisms, which are already under stress during shock. Such perfusion pressure deficit may consequently impact organs' ability to function or recover from an injured state. This review discusses such pathophysiologic mechanisms in detail with a particular focus on the risk of new-onset acute kidney injury (AKI). To review current literature, databases of Medline, Embase, and Google scholar were searched to retrieve articles that either adjusted BP targets based on patients' premorbid BP levels or considered relative hypotension as an exposure endpoint and assessed its association with clinical outcomes among acutely ill patients. There were no randomized controlled trials. Only seven studies could be identified and these were reviewed in detail. These studies indicated a significant association between the degree of relative hypotension that was inadvertently accepted in real-world practice and new-onset organ dysfunction or subsequent AKI. However, this is not a high-quality evidence. Therefore, well-designed randomized controlled trials are needed to evaluate whether adoption of individualized BP targets, which are initially guided by patient's premorbid basal BP and then tailored according to clinical response, is superior to conventional BP targets for vasopressor therapy, particularly among patients with vasodilatory shock states.
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Sperna Weiland NH, Hermanides J, van der Ster BJP, Hollmann MW, Preckel B, Stok WJ, van Lieshout JJ, Immink RV. Sevoflurane based anaesthesia does not affect already impaired cerebral autoregulation in patients with type 2 diabetes mellitus. Br J Anaesth 2018; 121:1298-1307. [PMID: 30442257 DOI: 10.1016/j.bja.2018.07.037] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 06/11/2018] [Accepted: 07/09/2018] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND The baroreflex regulates arterial blood pressure (BP). During periods when blood pressure changes, cerebral blood flow (CBF) is kept constant by cerebral autoregulation (CA). In patients with diabetes mellitus (DM), low baroreflex sensitivity (BRS) is associated with impaired CA. As sevoflurane-based anaesthesia obliterates BRS, we hypothesised that this could aggravate the already impaired CA in patients with DM resulting in a 'double-hit' on cerebral perfusion leading to increased fluctuations in blood pressure and cerebral perfusion. METHODS On the day before surgery, we measured CBF velocity (CBFV), heart rate, and BP to determine BRS and CA efficacy (CBFVmean-to-BPmean-phase lead) in 25 patients with DM and in 14 controls. During the operation, BRS and CA efficacy were determined during sevoflurane-based anaesthesia. Patients with DM were divided into a group with high BRS (DMBRS↑) and a group with low BRS (DMBRS↓). Values presented are median (inter-quartile range). RESULTS Preoperative vs intraoperative BRS was 6.2 (4.5-8.5) vs 1.9 (1.1-2.5, P<0.001) ms mm Hg-1 for controls, 5.8 (4.9-7.6) vs 2.7 (1.5-3.9, P<0.001) ms mm Hg-1 for patients with DMBRS↑, and 1.9 (1.5-2.8) vs 1.1 (0.6-2.5, P=0.31) ms mm Hg-1 for patients with DMBRS↓. Preoperative vs intraoperative CA efficacy was 43° (38-46) vs 43° (38-51, P=0.30), 44° (36-49) vs 41° (32-49, P=0.52), and 34° (28-40) vs 30° (27-38, P=0.64) for controls, DMBRS↑, and DMBRS↓ patients, respectively. CONCLUSIONS In diabetic patients with low preoperative BRS, preoperative CA efficacy was also impaired. In controls and diabetic patients, CA was unaffected by sevoflurane-based anaesthesia. We therefore conclude that sevoflurane-based anaesthesia does not contribute to a 'double-hit' phenomenon on cerebral perfusion. CLINICAL TRIAL REGISTRATION NCT 03071432.
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Affiliation(s)
- N H Sperna Weiland
- Amsterdam UMC, University of Amsterdam, Anaesthesiology, Amsterdam, The Netherlands; Amsterdam UMC, University of Amsterdam, Laboratory for Clinical Cardiovascular Physiology, Department of Medical Biology, Amsterdam, The Netherlands
| | - J Hermanides
- Amsterdam UMC, University of Amsterdam, Anaesthesiology, Amsterdam, The Netherlands.
| | - B J P van der Ster
- Amsterdam UMC, University of Amsterdam, Laboratory for Clinical Cardiovascular Physiology, Department of Medical Biology, Amsterdam, The Netherlands; Amsterdam UMC, University of Amsterdam, Internal Medicine, Amsterdam, The Netherlands
| | - M W Hollmann
- Amsterdam UMC, University of Amsterdam, Anaesthesiology, Amsterdam, The Netherlands
| | - B Preckel
- Amsterdam UMC, University of Amsterdam, Anaesthesiology, Amsterdam, The Netherlands
| | - W J Stok
- Amsterdam UMC, University of Amsterdam, Laboratory for Clinical Cardiovascular Physiology, Department of Medical Biology, Amsterdam, The Netherlands
| | - J J van Lieshout
- Amsterdam UMC, University of Amsterdam, Laboratory for Clinical Cardiovascular Physiology, Department of Medical Biology, Amsterdam, The Netherlands; Amsterdam UMC, University of Amsterdam, Internal Medicine, Amsterdam, The Netherlands; MRC/Arthritis Research UK Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, UK
| | - R V Immink
- Amsterdam UMC, University of Amsterdam, Anaesthesiology, Amsterdam, The Netherlands; Amsterdam UMC, University of Amsterdam, Laboratory for Clinical Cardiovascular Physiology, Department of Medical Biology, Amsterdam, The Netherlands
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Coucha M, Abdelsaid M, Ward R, Abdul Y, Ergul A. Impact of Metabolic Diseases on Cerebral Circulation: Structural and Functional Consequences. Compr Physiol 2018; 8:773-799. [PMID: 29687902 DOI: 10.1002/cphy.c170019] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Metabolic diseases including obesity, insulin resistance, and diabetes have profound effects on cerebral circulation. These diseases not only affect the architecture of cerebral blood arteries causing adverse remodeling, pathological neovascularization, and vasoregression but also alter the physiology of blood vessels resulting in compromised myogenic reactivity, neurovascular uncoupling, and endothelial dysfunction. Coupled with the disruption of blood brain barrier (BBB) integrity, changes in blood flow and microbleeds into the brain rapidly occur. This overview is organized into sections describing cerebrovascular architecture, physiology, and BBB in these diseases. In each section, we review these properties starting with larger arteries moving into smaller vessels. Where information is available, we review in the order of obesity, insulin resistance, and diabetes. We also tried to include information on biological variables such as the sex of the animal models noted since most of the information summarized was obtained using male animals. © 2018 American Physiological Society. Compr Physiol 8:773-799, 2018.
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Affiliation(s)
- Maha Coucha
- South University, School of Pharmacy, Savannah, Georgia, USA
| | | | - Rebecca Ward
- Department of Neuroscience & Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Yasir Abdul
- Charlie Norwood VA Medical Center, Augusta, Georgia, USA.,Department of Physiology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Adviye Ergul
- Charlie Norwood VA Medical Center, Augusta, Georgia, USA.,Department of Physiology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
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van der Velpen IF, Yancy CW, Sorond FA, Sabayan B. Impaired Cardiac Function and Cognitive Brain Aging. Can J Cardiol 2017; 33:1587-1596. [DOI: 10.1016/j.cjca.2017.07.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Revised: 07/16/2017] [Accepted: 07/16/2017] [Indexed: 12/25/2022] Open
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Yoshida H, Hamner JW, Ishibashi K, Tan CO. Relative contributions of systemic hemodynamic variables to cerebral autoregulation during orthostatic stress. J Appl Physiol (1985) 2017; 124:321-329. [PMID: 29025902 DOI: 10.1152/japplphysiol.00700.2017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Postural changes impair the ability of the cerebrovasculature to buffer against dynamic pressure fluctuations, but the mechanisms underlying this impairment have not been elucidated. We hypothesized that autoregulatory impairment may reflect the impact of static central volume shifts on hemodynamic factors other than arterial pressure (AP). In 14 young volunteers, we assessed the relation of fluctuations in cerebral blood flow (CBF) to those in AP, cardiac output, and CO2, during oscillatory lower body pressure (LBP) (±20 mmHg at 0.01 and 0.06 Hz) at three static levels (-20, 0, and +20 mmHg). Static and dynamic changes in AP, cardiac output, and CO2 explained over 70% of the variation in CBF fluctuations. However, their contributions were different across frequencies and levels: dynamic AP changes explained a substantial proportion of the variation in faster CBF fluctuations (partial R2 = 0.75, standardized β = 0.83, P < 0.01), whereas those in CO2 explained the largest portion of the variation in slow fluctuations (partial R2 = 0.43, β = 0.51, P < 0.01). There was, however, a major contribution of slow dynamic AP changes during negative (β = 0.43) but not neutral (β = 0.05) or positive (β = -0.07) LBP. This highlights the differences in contributions of systemic variables to dynamic and static autoregulation and has important implications for understanding orthostatic intolerance. NEW & NOTEWORTHY While fluctuations in blood pressure drive faster fluctuations in cerebral blood flow, overall level of CO2 and the magnitude of its fluctuations, along with cardiac output, determine the magnitude of slow ones. The effect of slow blood pressure fluctuations on cerebrovascular responses becomes apparent only during pronounced central volume shifts (such as when standing). This underlines distinct but interacting contributions of static and dynamic changes in systemic hemodynamic variables to the cerebrovascular regulation.
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Affiliation(s)
- Hisao Yoshida
- Graduate School of Engineering, Chiba University , Chiba , Japan
| | - Jason W Hamner
- Cerebrovascular Research Laboratory, Spaulding Rehabilitation Hospital , Boston, Massachusetts
| | - Keita Ishibashi
- Graduate School of Engineering, Chiba University , Chiba , Japan
| | - Can Ozan Tan
- Cerebrovascular Research Laboratory, Spaulding Rehabilitation Hospital , Boston, Massachusetts.,Department of Physical Medicine and Rehabilitation, Harvard Medical School , Boston, Massachusetts
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Berkhout-Byrne N, Kallenberg MH, Gaasbeek A, Rabelink TJ, Hammer S, van Buchem MA, van Osch MJ, Kroft LJM, Boom H, Mooijaart SP, van Buren M. The Cognitive decline in Older Patients with End stage renal disease (COPE) study - rationale and design. Curr Med Res Opin 2017; 33:2057-2064. [PMID: 28604116 DOI: 10.1080/03007995.2017.1341404] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
BACKGROUND Older patients with end stage renal disease (ESRD) are at increased risk for cognitive decline, but detailed studies of the magnitude of cognitive decline on dialysis or comprehensive conservative management (CCM) are lacking and the underlying pathophysiological mechanisms have poorly been studied. OBJECTIVES To describe the rationale and design of the COPE study. Study objectives are as follows. Firstly, to examine the severity of cognitive impairment in older patients reaching ESRD before dialysis and the rate of decline after dialysis or CCM initiation. Secondly, to study the association of blood biomarkers for microvascular damage and MRI derived measurements of small vessel disease with the rate of cognitive decline. Thirdly, to examine to what extent cardiac function is related to brain structure and perfusion in patients reaching ESRD. Finally, to study the association of cognitive and functional capacity with quality of life in pre-dialysis patients, as well as after dialysis or CCM initiation. STUDY DESIGN AND METHODS The COPE study is a prospective, multicenter cohort study in the Netherlands, including prevalent and incident pre-dialysis patients ≥65 years old with eGFR ≤20 ml/min/1.73 m2, awaiting either dialysis or CCM initiation. At baseline extensive data is collected including a comprehensive geriatric assessment and laboratory tests. Brain and cardiac MRI for analysis of structural and functional abnormalities are performed at baseline and repeated following therapy change. All other measurements are repeated annually during four years of follow up, including an extra evaluation six months after initiation of dialysis. CONCLUSIONS Knowledge of the magnitude of cognitive decline and its underlying pathophysiological mechanism, as well as its impact on functionality and quality of life can eventually help to postulate an algorithm for well balanced decision making in treatment strategies in older patients reaching ESRD. CLINICAL TRIAL REGISTRATION The COPE study is registered on www.ccmo.nl (number: NL46389.058.13).
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Affiliation(s)
- Noeleen Berkhout-Byrne
- a Department of Nephrology , Leiden University Medical Center , Leiden , The Netherlands
| | - Marije H Kallenberg
- a Department of Nephrology , Leiden University Medical Center , Leiden , The Netherlands
- b Department of Gerontology and Geriatrics , Leiden University Medical Center , Leiden , The Netherlands
| | - André Gaasbeek
- a Department of Nephrology , Leiden University Medical Center , Leiden , The Netherlands
| | - Ton J Rabelink
- a Department of Nephrology , Leiden University Medical Center , Leiden , The Netherlands
| | - Sebastiaan Hammer
- c Department of Radiology , Leiden University Medical Center , Leiden , The Netherlands
- d Department of Radiology , HAGA Hospital , The Hague , The Netherlands
| | - Mark A van Buchem
- c Department of Radiology , Leiden University Medical Center , Leiden , The Netherlands
| | - Matthias J van Osch
- c Department of Radiology , Leiden University Medical Center , Leiden , The Netherlands
| | - Lucia J M Kroft
- c Department of Radiology , Leiden University Medical Center , Leiden , The Netherlands
| | - Henk Boom
- e Department of Nephrology , Reinier de Graaf Group , Delft , The Netherlands
| | - Simon P Mooijaart
- b Department of Gerontology and Geriatrics , Leiden University Medical Center , Leiden , The Netherlands
- f Institute for Evidence-based Medicine in Old Age (IEMO) , Leiden , The Netherlands
| | - Marjolijn van Buren
- a Department of Nephrology , Leiden University Medical Center , Leiden , The Netherlands
- g Department of Nephrology , HAGA Hospital , The Hague , The Netherlands
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Selvarajah D, Hughes T, Reeves J, Boland E, Marques J, Gandhi R, Griffiths PD, Tesfaye S, Wilkinson ID. A preliminary study of brain macrovascular reactivity in impaired glucose tolerance and type-2 diabetes: Quantitative internal carotid artery blood flow using magnetic resonance phase contrast angiography. Diab Vasc Dis Res 2016; 13:367-72. [PMID: 27190084 DOI: 10.1177/1479164116644404] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
OBJECTIVE The aims of this study were (1) to examine cerebrovascular autoregulation in subjects with impaired glucose tolerance and type 2 diabetes and (2) to clarify whether cardiovascular autonomic nerve function is associated with abnormal cerebrovascular autoregulation. RESEARCH DESIGN AND METHODS Totally, 46 subjects were recruited (12 = impaired glucose tolerance, 17 = type 2 diabetes and 17 = healthy volunteers). Arterial blood flow was assessed within the internal carotid artery at baseline and 20 min after intravenous pharmacological stress (1 g acetazolamide), using quantitative magnetic resonance phase-contrast angiography. Internal carotid artery vascular reactivity and pulsatility index was determined. All subjects underwent baroreceptor reflex sensitivity assessment. RESULTS Subjects with impaired glucose tolerance and type 2 diabetes had significantly lower internal carotid artery vascular reactivity [40.2%(19.8) and 41.5%(18.7)], respectively, compared with healthy volunteers [57.0%(14.2); analysis of variance, p = 0.02]. There was no significant difference in internal carotid artery vascular reactivity between type 2 diabetes and impaired glucose tolerance groups (p = 0.84). There was a significant positive correlation between baroreceptor reflex sensitivity (low frequency:high frequency) with cardiac rhythm variability (ρ = 0.47, p = 0.04) and PI (ρ = 0.46, p = 0.04). CONCLUSION We have demonstrated significant cerebrovascular haemodynamic abnormalities in subjects with type 2 diabetes and impaired glucose tolerance. This was associated with greater sympathovagal imbalance. This may provide an important mechanistic explanation for increased risk of cerebrovascular disease in diabetes. It also highlights that these abnormalities may already be present in prediabetes.
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Affiliation(s)
- Dinesh Selvarajah
- Department of Human Metabolism, The University of Sheffield, Sheffield, UK
| | - Timothy Hughes
- Academic Unit of Radiology, The University of Sheffield, Sheffield, UK
| | - Josie Reeves
- Academic Unit of Radiology, The University of Sheffield, Sheffield, UK
| | - Elaine Boland
- Academic Unit of Radiology, The University of Sheffield, Sheffield, UK
| | - Jefferson Marques
- Academic Unit of Diabetes and Endocrinology, Royal Hallamshire Hospital, Sheffield, UK
| | - Rajiv Gandhi
- Academic Unit of Diabetes and Endocrinology, Royal Hallamshire Hospital, Sheffield, UK
| | - Paul D Griffiths
- Academic Unit of Radiology, The University of Sheffield, Sheffield, UK
| | - Solomon Tesfaye
- Academic Unit of Diabetes and Endocrinology, Royal Hallamshire Hospital, Sheffield, UK
| | - Iain D Wilkinson
- Academic Unit of Radiology, The University of Sheffield, Sheffield, UK
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Ryan DJ, Harbison JA, Meaney JF, Rice CP, King-Kallimanis B, Kenny RA. Syncope causes transient focal neurological symptoms. QJM 2015; 108:711-8. [PMID: 25630908 DOI: 10.1093/qjmed/hcv005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Indexed: 01/04/2023] Open
Abstract
AIMS The prevalence of focal neurology (FN) as a consequence of syncope is unknown. The aim of the study was to determine its prevalence, risk factors and short-term consequences. METHODS A consecutive sample of syncope-unit attendees during a 9-month period had detailed diagnostic syncope evaluation as per European Cardiac Society guidelines coupled with assessment for FN present during syncope/pre-syncope by screening questionnaire, follow-up interview and neuroimaging (1.5T magnetic resonance imaging [MRI]). All participants were followed up for 24 months. Risk factors for FN were identified by comparing FN cases with syncope controls without FN (3:1 ratio). RESULTS Five-hundred and forty consecutively attended for investigation of syncope (n = 401) and pre-syncope (n = 139). Thirty-one (5.7%) had FN events during hypotensive symptoms, mean age 49 years (19-85). The majority of FN cases had vasovagal syncope (VVS); 22 (71%), whereas eight had OH (25.8%) and one (3.2%) had cardiac arrhythmia. Median duration of FN was 15 min (IQR: 34.5). MRI in 28 (90%) was normal and in 3, old cerebral infarction was evident. Risk factors for FN/syncope were frequent syncope (P = 0·008), childhood syncope (P < 0.0005) and delayed diastolic recovery during active stand (P = 0·02). During 24-month follow-up and targeted intervention, no patients developed recurrence of FN. CONCLUSION One in 20 patients with syncope/pre-syncope have co-extant FN, which during 24-month follow-up, does not progress to a persistent deficit (>24 h). Awareness of co-occurrence of FN and syncope is important as stroke misdiagnosis results in aggressive anti-hypertensive management and future events may ensue.
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Affiliation(s)
- D J Ryan
- From the Trinity College Institute of Neuroscience (TCIN), Trinity College Dublin, Dublin 2, Ireland and
| | - J A Harbison
- From the Trinity College Institute of Neuroscience (TCIN), Trinity College Dublin, Dublin 2, Ireland and
| | - J F Meaney
- Centre of Advanced Medical Imaging, St. James's Hospital, St. James's Street, Dublin 8, Ireland
| | - C P Rice
- From the Trinity College Institute of Neuroscience (TCIN), Trinity College Dublin, Dublin 2, Ireland and
| | - B King-Kallimanis
- From the Trinity College Institute of Neuroscience (TCIN), Trinity College Dublin, Dublin 2, Ireland and
| | - R A Kenny
- From the Trinity College Institute of Neuroscience (TCIN), Trinity College Dublin, Dublin 2, Ireland and
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Cerebral autoregulation in the microvasculature measured with near-infrared spectroscopy. J Cereb Blood Flow Metab 2015; 35:959-66. [PMID: 25669906 PMCID: PMC4640259 DOI: 10.1038/jcbfm.2015.5] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 12/17/2014] [Accepted: 01/06/2015] [Indexed: 01/27/2023]
Abstract
Cerebral autoregulation (CA) is the mechanism that allows the brain to maintain a stable blood flow despite changes in blood pressure. Dynamic CA can be quantified based on continuous measurements of systemic mean arterial pressure (MAP) and global cerebral blood flow. Here, we show that dynamic CA can be quantified also from local measurements that are sensitive to the microvasculature. We used near-infrared spectroscopy (NIRS) to measure temporal changes in oxy- and deoxy-hemoglobin concentrations in the prefrontal cortex of 11 human subjects. A novel hemodynamic model translates those changes into changes of cerebral blood volume and blood flow. The interplay between them is described by transfer function analysis, specifically by a high-pass filter whose cutoff frequency describes the autoregulation efficiency. We have used pneumatic thigh cuffs to induce MAP perturbation by a fast release during rest and during hyperventilation, which is known to enhance autoregulation. Based on our model, we found that the autoregulation cutoff frequency increased during hyperventilation in comparison to normal breathing in 10 out of 11 subjects, indicating a greater autoregulation efficiency. We have shown that autoregulation can reliably be measured noninvasively in the microvasculature, opening up the possibility of localized CA monitoring with NIRS.
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Kainerstorfer JM, Sassaroli A, Fantini S. Coherent hemodynamics spectroscopy in a single step. BIOMEDICAL OPTICS EXPRESS 2014; 5:3403-16. [PMID: 25360359 PMCID: PMC4206311 DOI: 10.1364/boe.5.003403] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 08/25/2014] [Accepted: 08/27/2014] [Indexed: 05/03/2023]
Abstract
Coherent Hemodynamics Spectroscopy (CHS) is a technique based on inducing cerebral hemodynamic oscillations at multiple frequencies, measuring them with near-infrared spectroscopy (NIRS), and analyzing them with a hemodynamic model to obtain physiological information such as blood transit times in the microvasculature and the autoregulation cutoff frequency. We have previously demonstrated that such oscillations can be induced one frequency at a time. Here we demonstrate that CHS can be performed by a single inflation of two pneumatic thigh cuffs (duration: 2 min; pressure: 200 mmHg), whose sudden release produces a step response in systemic arterial blood pressure that lasts for ~20 s and induces cerebral hemodynamics that contain all the frequency information necessary for CHS. Following a validation study on simulated data, we performed measurements on human subjects with this new method based on a single occlusion/release of the thigh cuffs and with the previous method based on sequential sets of cyclic inflation/deflation one frequency at a time, and demonstrated that the two methods yield the same CHS spectra and the same physiological parameters (within measurement errors). The advantages of the new method presented here are that CHS spectra cover the entire bandwidth of the induced hemodynamic response, they are measured over ~20 s thus better satisfying the requirement of time invariance of physiological conditions, and they can be measured every ~2.5 min thus achieving finer temporal sampling in monitoring applications.
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Lee JF, Harrison ML, Christmas KM, Kim K, Hurr C, Brothers RM. Elevated resting heart rate and reduced orthostatic tolerance in obese humans. Clin Auton Res 2013; 24:39-46. [PMID: 24292891 DOI: 10.1007/s10286-013-0222-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 11/15/2013] [Indexed: 10/26/2022]
Abstract
BACKGROUND Obesity is linked with numerous physiological impairments; however, its impact on orthostatic tolerance (OT) remains unknown. This study tested the hypothesis that OT is reduced in obese individuals, and that reduced heart rate (HR) reserve and impaired cerebral autoregulation contribute to impaired OT. METHODS Eleven obese (8 females) and 22 non-obese (10 females) individuals were exposed to incremental lower body negative pressure (LBNP) to presyncope while HR, arterial blood pressure, and cerebral perfusion (middle cerebral artery blood velocity; MCA V mean) were measured. OT was quantified with a cumulative stress index (CSI). RESULTS OT was reduced in obese subjects, and there was an inverse relationship between body mass index (BMI) and OT (R = -0.47). HR was higher at rest and during each level of LBNP completed by all subjects. Similar peak HR (HRpeak) during LBNP between obese and non-obese subjects resulted in obese having a higher %peak HR at rest and at each stage of LBNP compared. Relationships existed for BMI and resting %HRpeak (R = 0.45) and resting %HRpeak and CSI (R = -0.52). Despite lower CSI in obese, MCA V mean and indices of cerebral autoregulation were similar between groups at all time points. CONCLUSIONS These data suggest that OT is reduced in obese and a higher resting HR, but not impaired regulation of cerebral perfusion, may contribute to this reduction.
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Affiliation(s)
- Joshua F Lee
- Environmental and Autonomic Physiology Laboratory, Department of Kinesiology and Health Education, The University of Texas at Austin, 1 University Station: D-3700, Austin, TX, 78712, USA
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Panwar R, Lanyon N, Davies AR, Bailey M, Pilcher D, Bellomo R. Mean perfusion pressure deficit during the initial management of shock--an observational cohort study. J Crit Care 2013; 28:816-24. [PMID: 23849541 DOI: 10.1016/j.jcrc.2013.05.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 04/09/2013] [Accepted: 05/15/2013] [Indexed: 01/20/2023]
Abstract
PURPOSE It is unclear if blood pressure targets for patients with shock should be adjusted to pre-morbid levels. We aimed to investigate mean deficit between the achieved mean perfusion pressure (MPP) in vasopressor-treated patients and their estimated basal (resting) MPP, and assess whether MPP deficit has any association with subsequent acute kidney injury (AKI). MATERIALS AND METHODS Fifty-one consecutive, non-trauma patients, aged ≥40 years, with ≥2 organ dysfunction and requiring vasopressor≥4 hours were observed at an academic intensive care unit. Mean MPP deficit [=%(basal MPP-achieved MPP)/basal MPP] and % time spent with >20% MPP deficit were assessed during initial 72 vasopressor hours (T0-T72) for each patient. RESULTS Achieved MPP was unrelated to basal MPP (P=.99). Mean MPP deficit was 18% (95% CI 15-21). Patients spent 48% (95% CI 39-57) time with >20% MPP deficit. Despite similar risk scores at T0, subsequent AKI (≥2 RIFLE class increase from T0) occurred more frequently in patients with higher (>median) MPP deficit compared to patients with lower MPP deficit (56% vs 28%; P=.045). Incidence of subsequent AKI was also higher among patients who spent greater % time with >20% MPP deficit (P=.04). CONCLUSIONS Achieved blood pressure during vasopressor therapy had no relationship to the pre-morbid basal level. This resulted in significant and varying degree of relative hypotension (MPP deficit), which could be a modifiable risk factor for AKI in patients with shock.
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Affiliation(s)
- Rakshit Panwar
- Department of Anaesthesia, Intensive Care and Pain Medicine, John Hunter Hospital, Newcastle 2305, Australia.
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Prakash K, Chandran DS, Khadgawat R, Jaryal AK, Deepak KK. Correction for blood pressure improves correlation between cerebrovascular reactivity assessed by breath holding and 6% CO(2) breathing. J Stroke Cerebrovasc Dis 2013; 23:630-5. [PMID: 23830954 DOI: 10.1016/j.jstrokecerebrovasdis.2013.06.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 05/28/2013] [Accepted: 06/03/2013] [Indexed: 10/26/2022] Open
Abstract
BACKGROUND Changes in cerebral blood flow velocity to hypercapnia are associated with changes in systemic blood pressure (BP). These confounding BP-dependent changes in cerebral blood flow velocity cause misinterpretation of cerebrovascular reactivity (CVR) results. The objective of the study was to determine the relationship between CVR assessed by breath holding and 6% CO2 breathing after correcting for BP-dependent changes in cerebral blood flow velocity. METHODS In 33 patients of uncomplicated type 2 diabetes mellitus, CVR was assessed as percentage changes in cerebral blood flow velocity and cerebrovascular conductance index. RESULTS Percentage change in cerebral blood flow velocity during breath holding was positively correlated with that of during 6% CO2 breathing (r = .35; P = .0448). CVR during breath holding and 6% CO2 breathing were better correlated when expressed as percentage changes in cerebrovascular conductance index (r = .49; P = .0040). Similarly, breath-holding test results expressed as percentage changes in cerebral blood flow velocity correctly identified only 37.5% of the poor reactors to 6% CO2 breathing. However, when the breath-holding test results were expressed as percentage changes in cerebrovascular conductance index, 62.5% of the poor reactors to 6% CO2 breathing were correctly identified indicating a better agreement between the test results obtained by the 2 methods. CONCLUSION Cerebrovascular response to breath holding is better correlated with that of 6% CO2 breathing when changes in cerebral blood flow velocity were corrected for associated changes in BP.
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Affiliation(s)
- Kiran Prakash
- Department of Physiology, All India Institute of Medical Sciences, New Delhi, India
| | - Dinu S Chandran
- Department of Physiology, All India Institute of Medical Sciences, New Delhi, India
| | - Rajesh Khadgawat
- Department of Endocrinology and Metabolism, All India Institute of Medical Sciences, New Delhi, India
| | - Ashok Kumar Jaryal
- Department of Physiology, All India Institute of Medical Sciences, New Delhi, India.
| | - Kishore Kumar Deepak
- Department of Physiology, All India Institute of Medical Sciences, New Delhi, India
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Huq R, Philbey CE, Mistri AK, Panerai RB, Robinson TG. Dynamic cerebral autoregulation assessed by respiratory manoeuvres in non-insulin-treated Type 2 diabetes mellitus. Diabet Med 2012; 29:609-13. [PMID: 22004530 DOI: 10.1111/j.1464-5491.2011.03497.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS This study investigated dynamic cerebral autoregulation in Type 2 diabetes, where dynamic cerebral autoregulation may be impaired as a consequence of microvascular changes and/or autonomic neuropathy. METHODS Eleven healthy control subjects and 11 age- and sex-matched patients with Type 2 diabetes controlled with lifestyle modifications or oral anti-diabetes treatment were recruited. Dynamic cerebral autoregulation was calculated by the autoregressive moving average autoregulatory index from a continuous blood pressure and R-R interval (time between each ventricular systole) recording. End-tidal carbon dioxide was also monitored and changes in response to breath holding and hyperventilation as a metabolic stimulus were measured. RESULTS No significant differences were seen in cerebral blood flow velocity at baseline, or in response to breath holding between people with diabetes and control subjects, although the cerebral blood flow velocity response associated with hyperventilation was significantly reduced in the diabetes group. No significant differences in dynamic cerebral autoregulation were seen at baseline or in response to respiratory manoeuvres between the groups. CONCLUSIONS Dynamic cerebral autoregulation is not impaired in patients with Type 2 diabetes, although a small difference could not be excluded as the study was only powered to detect an autoregulatory index difference > 2 units. Further study in a larger population with a spectrum of disease severity may reveal clinically important differences.
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Affiliation(s)
- R Huq
- Ageing and Stroke Medicine Medical Physics Groups, Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
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Alveolar gas exchange and tissue deoxygenation during exercise in type 1 diabetes patients and healthy controls. Respir Physiol Neurobiol 2012; 181:267-76. [PMID: 22538274 DOI: 10.1016/j.resp.2012.04.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 03/16/2012] [Accepted: 04/06/2012] [Indexed: 11/22/2022]
Abstract
We used near-infrared spectroscopy to investigate whether leg and arm skeletal muscle and cerebral deoxygenation differ during incremental cycling exercise in men with type 1 diabetes (T1D, n=10, mean±SD age 33±7 years) and healthy control men (matched by age, anthrometry, and self-reported physical activity, CON, n=10, 32±7 years) to seek an explanation for lower aerobic capacity (˙VO2peak) often reported in T1D. T1D had lower ˙VO2peak (35±4mlkg(-1)min(-1) vs. 43±8mlkg(-1)min(-1), P<0.01) and peak work rate (219±33W vs. 290±44W, P<0.001) than CON. Leg muscle deoxygenation (↑ [deoxyhemoglobin]; ↓ tissue saturation index) was greater in T1D than CON at a given absolute submaximal work rate, but not at peak exercise, while arm muscle and cerebral deoxygenation were similar. Thus, in T1D compared with CON, faster leg muscle deoxygenation suggests limited circulatory ability to increase O(2) delivery as a plausible explanation for lower ˙VO2peak and earlier fatigue in T1D.
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Mazzeo AT, La Monaca E, Di Leo R, Vita G, Santamaria LB. Heart rate variability: a diagnostic and prognostic tool in anesthesia and intensive care. Acta Anaesthesiol Scand 2011; 55:797-811. [PMID: 21658013 DOI: 10.1111/j.1399-6576.2011.02466.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The autonomic nervous system (ANS) plays an important role in the human response to various internal and external stimuli, which can modify homeostasis, and exerts a tight control on essential functions such as circulation, respiration, thermoregulation and hormonal secretion. ANS dysfunction may complicate the perioperative course in the surgical patient undergoing anesthesia, increasing morbidity and mortality, and, therefore, it should be considered as an additional risk factor during pre-operative evaluation. Furthermore, ANS dysfunction may complicate the clinical course of critically ill patients admitted to intensive care units, in the case of trauma, sepsis, neurologic disorders and cardiovascular diseases, and its occurrence adversely affects the outcome. In the care of these patients, the assessment of autonomic function may provide useful information concerning pathophysiology, risk stratification, early prognosis prediction and treatment strategies. Given the role of ANS in the maintenance of systemic homeostasis, anesthesiologists and intensivists should recognize as critical the evaluation of ANS function. Measurement of heart rate variability (HRV) is an easily accessible window into autonomic activity. It is a low-cost, non-invasive and simple to perform method reflecting the balance of the ANS regulation of the heart rate and offers the opportunity to detect the presence of autonomic neuropathy complicating several illnesses. The present review provides anesthesiologists and intensivists with a comprehensive summary of the possible clinical implications of HRV measurements, suggesting that autonomic dysfunction testing could potentially represent a diagnostic and prognostic tool in the care of patients both in the perioperative setting as well as in the critical care arena.
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Affiliation(s)
- Anna Teresa Mazzeo
- Anaesthesia and NeuroIntensive Care Unit, Department of Neurosciences, Psychiatry and Anaesthesiology, University of Messina, Messina, Italy.
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Kim YS, Davis SC, Truijen J, Stok WJ, Secher NH, van Lieshout JJ. Intensive Blood Pressure Control Affects Cerebral Blood Flow in Type 2 Diabetes Mellitus Patients. Hypertension 2011; 57:738-45. [DOI: 10.1161/hypertensionaha.110.160523] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Type 2 diabetes mellitus is associated with microvascular complications, hypertension, and impaired dynamic cerebral autoregulation. Intensive blood pressure (BP) control in hypertensive type 2 diabetic patients reduces their risk of stroke but may affect cerebral perfusion. Systemic hemodynamic variables and transcranial Doppler-determined cerebral blood flow velocity (CBFV), cerebral CO
2
responsiveness, and cognitive function were determined after 3 and 6 months of intensive BP control in 17 type 2 diabetic patients with microvascular complications (T2DM+), in 18 diabetic patients without (T2DM−) microvascular complications, and in 16 nondiabetic hypertensive patients. Cerebrovascular reserve capacity was lower in T2DM+ versus T2DM− and nondiabetic hypertensive patients (4.6±1.1 versus 6.0±1.6 [
P
<0.05] and 6.6±1.7 [
P
<0.01], Δ%mean CBFV/mm Hg). After 6 months, the attained BP was comparable among the 3 groups. However, in contrast to nondiabetic hypertensive patients, intensive BP control reduced CBFV in T2DM− (58±9 to 54±12 cm · s
−1
) and T2DM+ (57±13 to 52±11 cm · s
−1
) at 3 months, but CBFV returned to baseline at 6 months only in T2DM−, whereas the reduction in CBFV progressed in T2DM+ (to 48±8 cm · s
−1
). Cognitive function did not change during the 6 months. Static cerebrovascular autoregulation appears to be impaired in type 2 diabetes mellitus, with a transient reduction in CBFV in uncomplicated diabetic patients on tight BP control, but with a progressive reduction in CBFV in diabetic patients with microvascular complications, indicating that maintenance of cerebral perfusion during BP treatment depends on the progression of microvascular disease. We suggest that BP treatment should be individualized, aiming at a balance between BP reduction and maintenance of CBFV.
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Affiliation(s)
- Yu-Sok Kim
- From the Departments of Internal Medicine (Y.-S.K., J.T., J.J.v.L.) and Physiology (W.J.S.), Academic Medical Center and Laboratory for Clinical Cardiovascular Physiology, Academic Medical Center, Center for Heart Failure Research (Y.-S.K., S.C.A.T.D., J.T., W.J.S., J.J.v.L.), University of Amsterdam, Amsterdam, The Netherlands; Department of Anesthesia (N.H.S.), Copenhagen Muscle Research Center, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Shyrin C.A.T. Davis
- From the Departments of Internal Medicine (Y.-S.K., J.T., J.J.v.L.) and Physiology (W.J.S.), Academic Medical Center and Laboratory for Clinical Cardiovascular Physiology, Academic Medical Center, Center for Heart Failure Research (Y.-S.K., S.C.A.T.D., J.T., W.J.S., J.J.v.L.), University of Amsterdam, Amsterdam, The Netherlands; Department of Anesthesia (N.H.S.), Copenhagen Muscle Research Center, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Jasper Truijen
- From the Departments of Internal Medicine (Y.-S.K., J.T., J.J.v.L.) and Physiology (W.J.S.), Academic Medical Center and Laboratory for Clinical Cardiovascular Physiology, Academic Medical Center, Center for Heart Failure Research (Y.-S.K., S.C.A.T.D., J.T., W.J.S., J.J.v.L.), University of Amsterdam, Amsterdam, The Netherlands; Department of Anesthesia (N.H.S.), Copenhagen Muscle Research Center, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Wim J. Stok
- From the Departments of Internal Medicine (Y.-S.K., J.T., J.J.v.L.) and Physiology (W.J.S.), Academic Medical Center and Laboratory for Clinical Cardiovascular Physiology, Academic Medical Center, Center for Heart Failure Research (Y.-S.K., S.C.A.T.D., J.T., W.J.S., J.J.v.L.), University of Amsterdam, Amsterdam, The Netherlands; Department of Anesthesia (N.H.S.), Copenhagen Muscle Research Center, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Niels H. Secher
- From the Departments of Internal Medicine (Y.-S.K., J.T., J.J.v.L.) and Physiology (W.J.S.), Academic Medical Center and Laboratory for Clinical Cardiovascular Physiology, Academic Medical Center, Center for Heart Failure Research (Y.-S.K., S.C.A.T.D., J.T., W.J.S., J.J.v.L.), University of Amsterdam, Amsterdam, The Netherlands; Department of Anesthesia (N.H.S.), Copenhagen Muscle Research Center, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Johannes J. van Lieshout
- From the Departments of Internal Medicine (Y.-S.K., J.T., J.J.v.L.) and Physiology (W.J.S.), Academic Medical Center and Laboratory for Clinical Cardiovascular Physiology, Academic Medical Center, Center for Heart Failure Research (Y.-S.K., S.C.A.T.D., J.T., W.J.S., J.J.v.L.), University of Amsterdam, Amsterdam, The Netherlands; Department of Anesthesia (N.H.S.), Copenhagen Muscle Research Center, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
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Schytz HW, Hansson A, Phillip D, Selb J, Boas DA, Iversen HK, Ashina M. Spontaneous low-frequency oscillations in cerebral vessels: applications in carotid artery disease and ischemic stroke. J Stroke Cerebrovasc Dis 2011; 19:465-74. [PMID: 20864356 DOI: 10.1016/j.jstrokecerebrovasdis.2010.06.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2009] [Accepted: 12/02/2009] [Indexed: 11/30/2022] Open
Abstract
The etiology behind and physiological significance of spontaneous oscillations in the low-frequency spectrum in both systemic and cerebral vessels remain unknown. Experimental studies have proposed that spontaneous oscillations in cerebral blood flow reflect impaired cerebral autoregulation (CA). Analysis of CA by measurement of spontaneous oscillations in the low-frequency spectrum in cerebral vessels might be a useful tool for assessing risk and investigating different treatment strategies in carotid artery disease (CAD) and stroke. We reviewed studies exploring spontaneous oscillations in the low-frequency spectrum in patients with CAD and ischemic stroke, conditions known to involve impaired CA. Several studies have reported changes in oscillations after CAD and stroke after surgery and over time compared with healthy controls. Phase shift in the frequency domain and correlation coefficients in the time domain are the most frequently used parameters for analyzing spontaneous oscillations in systemic and cerebral vessels. At present, there is no gold standard for analyzing spontaneous oscillations in the low-frequency spectrum, and simplistic models of CA have failed to predict or explain the spontaneous oscillation changes found in CAD and stroke studies. Near-infrared spectroscopy is suggested as a future complementary tool for assessing changes affecting the cortical arterial system.
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Affiliation(s)
- Henrik W Schytz
- Danish Headache Center, Department of Neurology, Glostrup Hospital, Faculty of Health Sciences, University of Copenhagen, Glostrup, Denmark.
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Nasr N, Czosnyka M, Arevalo F, Hanaire H, Guidolin B, Larrue V. Autonomic neuropathy is associated with impairment of dynamic cerebral autoregulation in type 1 diabetes. Auton Neurosci 2010; 160:59-63. [PMID: 21036672 DOI: 10.1016/j.autneu.2010.10.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2010] [Revised: 09/07/2010] [Accepted: 10/04/2010] [Indexed: 11/30/2022]
Abstract
HYPOTHESIS The mechanisms underlying impairment of dynamic cerebral autoregulation in diabetes are not well known. Cardiovascular autonomic neuropathy (CAN) could contribute to dynamic cerebral autoregulation impairment. In this study, we assessed the association between CAN and impairment of dynamic cerebral autoregulation in patients with type 1 diabetes. METHODS We evaluated dynamic cerebral autoregulation (DCA) in patients with type 1 diabetes and no history of cerebrovascular disease. DCA was assessed with transcranial Doppler using the correlation coefficient index Mx method. Mx was calculated from slow changes in mean cerebral blood flow velocity and mean arterial blood pressure. Increase in Mx indicates weaker DCA, with a threshold for impaired DCA above 0.3. Moderate CAN was defined as reduced heart rate variability (HRV) on the following tests: deep controlled breathing, Valsalva maneuver or initiation of active standing. Severe CAN was defined as reduced HRV associated with orthostatic hypotension. RESULTS 60 patients were included (M/F: 33/27; mean age ± SD: 46 years ± 11.5). 23 patients had moderate CAN and 15 patients severe CAN. DCA was impaired in 37 patients. CAN was associated with impaired DCA (p = 0.005). Impairment of DCA was more pronounced in patients with severe CAN (p = 0.019). Glycosylated haemoglobin (HbA1c) was associated with impaired DCA in univariate analysis (p = 0.05). In multivariate analysis, only CAN was associated with impaired DCA (p = 0.007) whereas HbA1c was not (p = 0.161). CONCLUSIONS CAN was associated with impaired DCA in type 1 diabetes. The magnitude of DCA impairment increased with the severity of CAN.
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Affiliation(s)
- N Nasr
- Service de Neurologie Vasculaire, Hôpital Rangueil, Toulouse, INSERM U, France.
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Panerai RB. Transcranial Doppler for evaluation of cerebral autoregulation. Clin Auton Res 2009; 19:197-211. [PMID: 19370374 DOI: 10.1007/s10286-009-0011-8] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2008] [Accepted: 03/13/2009] [Indexed: 12/14/2022]
Abstract
Transcranial Doppler ultrasound (TCD) can measure cerebral blood flow velocity in the main intracranial vessels non-invasively and with high accuracy. Combined with the availability of non-invasive devices for continuous measurement of arterial blood pressure, the relatively low cost, ease-of-use, and excellent temporal resolution of TCD have stimulated the development of new techniques to assess cerebral autoregulation in the laboratory or bedside using a dynamic approach, instead of the more classical 'static' method. Clinical applications have shown consistent results in certain conditions such as severe head injury and carotid artery disease. Studies in syncopal patients revealed a more complex pattern due to aetiological non-homogeneity and methodological limitations mainly due to inadequate sample-size. Different analytical models to quantify autoregulatory performance have also contributed to the diversity of results in the literature. The review concludes with specific recommendations for areas where further validation and research are needed to improve the reliability and usefulness of TCD in clinical practice.
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Affiliation(s)
- Ronney B Panerai
- Medical Physics Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, UK.
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43
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44
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Dynamic cerebral autoregulatory capacity is affected early in Type 2 diabetes. Clin Sci (Lond) 2008; 115:255-62. [PMID: 18348713 DOI: 10.1042/cs20070458] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Type 2 diabetes is associated with an increased risk of endothelial dysfunction and microvascular complications with impaired autoregulation of tissue perfusion. Both microvascular disease and cardiovascular autonomic neuropathy may affect cerebral autoregulation. In the present study, we tested the hypothesis that, in the absence of cardiovascular autonomic neuropathy, cerebral autoregulation is impaired in subjects with DM+ (Type 2 diabetes with microvascular complications) but intact in subjects with DM- (Type 2 diabetes without microvascular complications). Dynamic cerebral autoregulation and the steady-state cerebrovascular response to postural change were studied in subjects with DM+ and DM-, in the absence of cardiovascular autonomic neuropathy, and in CTRL (healthy control) subjects. The relationship between spontaneous changes in MCA V(mean) (middle cerebral artery mean blood velocity) and MAP (mean arterial pressure) was evaluated using frequency domain analysis. In the low-frequency region (0.07-0.15 Hz), the phase lead of the MAP-to-MCA V(mean) transfer function was 52+/-10 degrees in CTRL subjects, reduced in subjects with DM- (40+/-6 degrees ; P<0.01 compared with CTRL subjects) and impaired in subjects with DM+ (30+/-5 degrees ; P<0.01 compared with subjects with DM-), indicating less dampening of blood pressure oscillations by affected dynamic cerebral autoregulation. The steady-state response of MCA V(mean) to postural change was comparable for all groups (-12+/-6% in CTRL subjects, -15+/-6% in subjects with DM- and -15+/-7% in subjects with DM+). HbA(1c) (glycated haemoglobin) and the duration of diabetes, but not blood pressure, were determinants of transfer function phase. In conclusion, dysfunction of dynamic cerebral autoregulation in subjects with Type 2 diabetes appears to be an early manifestation of microvascular disease prior to the clinical expression of diabetic nephropathy, retinopathy or cardiovascular autonomic neuropathy.
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45
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Marked reduction in bispectral index with severe bradycardia without hypotension in a diabetic patient undergoing ophthalmic surgery. J Anesth 2008; 22:300-3. [DOI: 10.1007/s00540-008-0632-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2008] [Accepted: 03/30/2008] [Indexed: 10/21/2022]
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46
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Gonul M, Asil T, Balci K, Celik Y, Turgut N, Uzunca I. Changing cerebral blood flow velocity detected by transcranial Doppler ultrasound during head up tilt in patients with multiple sclerosis. Eur J Neurol 2008; 15:725-9. [PMID: 18505409 DOI: 10.1111/j.1468-1331.2008.02179.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND AND PURPOSE Multiple sclerosis (MS) is a chronic inflammatory disease of central nervous system. We aimed to investigate the cerebral blood flow velocity (CBFV) changes in MS by transcranial Doppler. METHODS Twenty patients with MS, 20 age-matched healthy controls were included in the study. In both groups, blood flow velocities (BFVs) of middle cerebral arteries (MCAs) were evaluated. The changes of blood pressure, heart rate along with the changes in BFV of MCA were recorded after the patients were raised to upright position. RESULTS In both groups, upon raising the tilt table to the upright position, the mean CBFV values were found to be lower in comparison with the recorded baseline values (P values <0.05). The decline in the mean CBFV values was more significant in patients with MS (P = 0.01). CONCLUSION Our study showed upon raise of the tilt table, the mean BFVs decreased more in MS patients than control group with a more prominent change in the subgroup of MS patients with expanded disability scale scores > or =2. By use of transcranial Doppler ultrasound, it may be possible to evaluate BFV changes in patients with MS.
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Affiliation(s)
- M Gonul
- Erzurum Numune Hospital, Clinics of Neurology, Erzurum, Turkey
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Brown CM, Marthol H, Zikeli U, Ziegler D, Hilz MJ. A simple deep breathing test reveals altered cerebral autoregulation in type 2 diabetic patients. Diabetologia 2008; 51:756-61. [PMID: 18309474 DOI: 10.1007/s00125-008-0958-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2007] [Accepted: 01/21/2008] [Indexed: 10/22/2022]
Abstract
AIMS/HYPOTHESIS Patients with diabetes mellitus have an increased risk of stroke and other cerebrovascular complications. The purpose of this study was to evaluate the autoregulation of cerebral blood flow in diabetic patients using a simple method that could easily be applied to the clinical routine screening of diabetic patients. METHODS We studied ten patients with type 2 diabetes mellitus and 11 healthy volunteer control participants. Continuous and non-invasive measurements of blood pressure and cerebral blood flow velocity were performed during deep breathing at 0.1 Hz (six breaths per minute). Cerebral autoregulation was assessed from the phase shift angle between breathing-induced 0.1 Hz oscillations in mean blood pressure and cerebral blood flow velocity. RESULTS The controls and patients all showed positive phase shift angles between breathing-induced 0.1 Hz blood pressure and cerebral blood flow velocity oscillations. However, the phase shift angle was significantly reduced (p < 0.05) in the patients (48 +/- 9 degrees ) compared with the controls (80 +/- 12 degrees ). The gain between 0.1 Hz oscillations in blood pressure and cerebral blood flow velocity did not differ significantly between the patients and controls. CONCLUSIONS/INTERPRETATION The reduced phase shift angle between oscillations in mean blood pressure and cerebral blood flow velocity during deep breathing suggests altered cerebral autoregulation in patients with diabetes and might contribute to an increased risk of cerebrovascular disorders.
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Affiliation(s)
- C M Brown
- Department of Neurology, University of Erlangen-Nuremberg, Erlangen, Germany.
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48
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Bohlen HG. Microvascular Consequences of Obesity and Diabetes. Microcirculation 2008. [DOI: 10.1016/b978-0-12-374530-9.00021-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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49
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Liau BY, Yeh SJ, Chiu CC, Tsai YC. Dynamic cerebral autoregulation assessment using chaotic analysis in diabetic autonomic neuropathy. Med Biol Eng Comput 2007; 46:1-9. [PMID: 17874153 DOI: 10.1007/s11517-007-0243-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2006] [Accepted: 08/14/2007] [Indexed: 11/24/2022]
Abstract
Cerebral autoregulation (CA) was assessed by chaotic analysis based on mean arterial blood pressure (MABP) and mean cerebral blood flow velocity (MCBFV) in 19 diabetics with autonomic neuropathy (AN) and 11 age-matched normal subjects. MABP in diabetics dropped significantly in response to tilting (91.6 +/- 14.9 vs. 74.1 +/- 13.4 mmHg, P < 0.05). Valsalva ratio of heart rate was reduced in diabetics compared to normal (1.1 +/- 0.1 vs. 1.5 +/- 0.2, P < 0.05). It indicated AN affects the vasomotor tone of peripheral vessels and baroreflex. Nonlinear results showed higher correlation dimension values of MABP and MCBFV in diabetics compared to normal, especially MABP (3.7 +/- 2.3 vs. 2.0 +/- 0.8, P < 0.05). It indicated CA is more complicated in diabetics. The lower Lyapunov exponent and the higher Kolmogorov entropy values in diabetics indicated less predictable behavior and higher chaotic degree. This study suggests impaired autoregulation would be more chaotic and less predictable.
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Affiliation(s)
- Ben-Yi Liau
- Graduate Institute of Electrical and Communications Engineering, Feng Chia University, Taichung, Taiwan, ROC
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50
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Kim YS, Krogh-Madsen R, Rasmussen P, Plomgaard P, Ogoh S, Secher NH, van Lieshout JJ. Effects of hyperglycemia on the cerebrovascular response to rhythmic handgrip exercise. Am J Physiol Heart Circ Physiol 2007; 293:H467-73. [PMID: 17369470 DOI: 10.1152/ajpheart.00045.2007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Dynamic cerebral autoregulation (CA) is challenged by exercise and may become less effective when exercise is exhaustive. Exercise may increase arterial glucose concentration, and we evaluated whether the cerebrovascular response to exercise is affected by hyperglycemia. The effects of a hyperinsulinemic euglycemic clamp (EU) and hyperglycemic clamp (HY) on the cerebrovascular (CVRI) and systemic vascular resistance index (SVRI) responses were evaluated in seven healthy subjects at rest and during rhythmic handgrip exercise. Transfer function analysis of the dynamic relationship between beat-to-beat changes in mean arterial pressure and middle cerebral artery (MCA) mean blood flow velocity ( Vmean) was used to assess dynamic CA. At rest, SVRI decreased with HY and EU ( P < 0.01). CVRI was maintained with EU but became reduced with HY [11% (SD 3); P < 0.01], and MCA Vmean increased ( P < 0.05), whereas brain catecholamine uptake and arterial Pco2 did not change significantly. HY did not affect the normalized low-frequency gain between mean arterial pressure and MCA Vmean or the phase shift, indicating maintained dynamic CA. With HY, the increase in CVRI associated with exercise was enhanced (19 ± 7% vs. 9 ± 7%; P < 0.05), concomitant with a larger increase in heart rate and cardiac output and a larger reduction in SVRI (22 ± 4% vs. 14 ± 2%; P < 0.05). Thus hyperglycemia lowered cerebral vascular tone independently of CA capacity at rest, whereas dynamic CA remained able to modulate cerebral blood flow around the exercise-induced increase in MCA Vmean. These findings suggest that elevated blood glucose does not explain that dynamic CA is affected during intense exercise.
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Affiliation(s)
- Yu-Sok Kim
- Medium Care Unit, Department of Internal Medicine, F7-205 Academic Medical Center, University of Amsterdam, 1100 DE Amsterdam, The Netherlands
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