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Ball JD, Davies A, Gurung D, Mankoo A, Panerai R, Minhas JS, Robinson T, Beishon L. The effect of posture on the age dependence of neurovascular coupling. Physiol Rep 2024; 12:e70031. [PMID: 39218618 PMCID: PMC11366444 DOI: 10.14814/phy2.70031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 08/23/2024] [Accepted: 08/23/2024] [Indexed: 09/04/2024] Open
Abstract
Previous studies report contradicting age-related neurovascular coupling (NVC). Few studies assess postural effects, but less investigate relationships between age and NVC within different postures. Therefore, this study investigated the effect of age on NVC in different postures with varying cognitive stimuli. Beat-to-beat blood pressure, heart rate and end-tidal carbon dioxide were assessed alongside middle and posterior cerebral artery velocities (MCAv and PCAv, respectively) using transcranial Doppler ultrasonography in 78 participants (31 young-, 23 middle- and 24 older-aged) with visuospatial (VST) and attention tasks (AT) in various postures at two timepoints (T2 and T3). Between-group significance testing utilized one-way analysis-of-variance (ANOVA) (Tukey post-hoc). Mixed three-way/one-way ANOVAs explored task, posture, and age interactions. Significant effects of posture on NVC were driven by a 3.8% increase from seated to supine. For AT, mean supine %MCAv increase was greatest in younger (5.44%) versus middle (0.12%) and older-age (0.09%) at T3 (p = 0.005). For VST, mean supine %PCAv increase was greatest at T2 and T3 in middle (10.99%/10.12%) and older-age (17.36%/17.26%) versus younger (9.44%/8.89%) (p = 0.004/p = 0.002). We identified significant age-related NVC effects with VST-induced hyperactivation. This may reflect age-related compensatory processes in supine. Further work is required, using complex stimuli while standing/walking, examining NVC, aging and falls.
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Affiliation(s)
- James D. Ball
- Department of Cardiovascular SciencesUniversity of LeicesterLeicesterUK
| | - Aaron Davies
- Department of Cardiovascular SciencesUniversity of LeicesterLeicesterUK
| | - Dewakar Gurung
- Department of Cardiovascular SciencesUniversity of LeicesterLeicesterUK
| | - Alex Mankoo
- Department of Cardiovascular SciencesUniversity of LeicesterLeicesterUK
| | - Ronney Panerai
- Department of Cardiovascular SciencesUniversity of LeicesterLeicesterUK
- NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research CentreGlenfield HospitalLeicesterUK
| | - Jatinder S. Minhas
- Department of Cardiovascular SciencesUniversity of LeicesterLeicesterUK
- NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research CentreGlenfield HospitalLeicesterUK
| | - Thompson Robinson
- Department of Cardiovascular SciencesUniversity of LeicesterLeicesterUK
- NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research CentreGlenfield HospitalLeicesterUK
| | - Lucy Beishon
- Department of Cardiovascular SciencesUniversity of LeicesterLeicesterUK
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Ince J, Panerai RB, Salinet ASM, Lam MY, Llwyd O, Haunton VJ, Robinson TG, Minhas JS. Dynamics of Critical Closing Pressure Explain Cerebral Autoregulation Impairment in Acute Cerebrovascular Disease. Cerebrovasc Dis 2024:1-9. [PMID: 38964310 DOI: 10.1159/000540206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Accepted: 06/06/2024] [Indexed: 07/06/2024] Open
Abstract
INTRODUCTION Cerebral autoregulation (CA) is impaired in acute ischemic stroke (AIS) and is associated with worse patient outcomes, but the underlying physiological cause is unclear. This study tests whether depressed CA in AIS can be linked to the dynamic responses of critical closing pressure (CrCP) and resistance area product (RAP). METHODS Continuous recordings of middle cerebral blood velocity (MCAv, transcranial Doppler), arterial blood pressure (BP), end-tidal CO2 and electrocardiography allowed dynamic analysis of the instantaneous MCAv-BP relationship to obtain estimates of CrCP and RAP. The dynamic response of CrCP and RAP to a sudden change in mean BP was obtained by transfer function analysis. Comparisons were made between younger controls (≤50 years), older controls (>50 years), and AIS patients. RESULTS Data from 24 younger controls (36.4 ± 10.9 years, 9 male), 38 older controls (64.7 ± 8.2 years, 20 male), and 20 AIS patients (63.4 ± 13.8 years, 9 male) were included. Dynamic CA was impaired in AIS, with lower autoregulation index (affected hemisphere: 4.0 ± 2.3, unaffected: 4.5 ± 1.8) compared to younger (right: 5.8 ± 1.4, left: 5.8 ± 1.4) and older (right: 4.9 ± 1.6, left: 5.1 ± 1.5) controls. AIS patients also demonstrated an early (0-3 s) peak in CrCP dynamic response that was not influenced by age. CONCLUSION These early transient differences in the CrCP dynamic response are a novel finding in stroke and occur too early to reflect underlying regulatory mechanisms. Instead, these may be caused by structural changes to cerebral vasculature.
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Affiliation(s)
- Jonathan Ince
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
| | - Ronney B Panerai
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
- NIHR Leicester Biomedical Research Centre, Leicester, UK
| | - Angela S M Salinet
- Neurology Department, Hospital das Clinicas, School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Man Y Lam
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
| | - Osian Llwyd
- Wolfson Centre for Prevention of Stroke and Dementia, Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Victoria J Haunton
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
| | - Thompson G Robinson
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
- NIHR Leicester Biomedical Research Centre, Leicester, UK
| | - Jatinder S Minhas
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
- NIHR Leicester Biomedical Research Centre, Leicester, UK
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Bello-Robles FA, Villalobos-Cid M, Chacón M, Inostroza-Ponta M. A multi-objective optimisation approach for the linear modelling of cerebral autoregulation system. Biosystems 2024; 241:105231. [PMID: 38754621 DOI: 10.1016/j.biosystems.2024.105231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 05/07/2024] [Accepted: 05/08/2024] [Indexed: 05/18/2024]
Abstract
OBJECTIVE Dynamic cerebral autoregulation (dCA) has been addressed through different approaches for discriminating between normal and impaired conditions based on spontaneous fluctuations in arterial blood pressure (ABP) and cerebral blood flow (CF). This work presents a novel multi-objective optimisation (MO) approach for finding good configurations of a cerebrovascular resistance-compliance model. METHODS Data from twenty-nine subjects under normo and hypercapnic (5% CO2 in air) conditions was used. Cerebrovascular resistance and vessel compliance models with ABP as input and CF velocity as output were fitted using a MO approach, considering fitting Pearson's correlation and error. RESULTS MO approach finds better model configurations than the single-objective (SO) approach, especially for hypercapnic conditions. In addition, the Pareto-optimal front from the multi-objective approach enables new information on dCA, reflecting a higher contribution of myogenic mechanism for explaining dCA impairment.
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Affiliation(s)
- Felipe-Andrés Bello-Robles
- Biomedical Engineering, Engineering Faculty, Universidad de Santiago de Chile, Address One, Santiago, 917022, Chile.
| | - Manuel Villalobos-Cid
- Informatics Engineering Department, Universidad de Santiago de Chile, Address One, Santiago, 917022, Chile
| | - Max Chacón
- Informatics Engineering Department, Universidad de Santiago de Chile, Address One, Santiago, 917022, Chile
| | - Mario Inostroza-Ponta
- Informatics Engineering Department, Universidad de Santiago de Chile, Address One, Santiago, 917022, Chile
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Panerai RB, Alshehri A, Beishon LC, Davies A, Haunton VJ, Katsogridakis E, Lam MY, Llwyd O, Robinson TG, Minhas JS. Determinants of the dynamic cerebral critical closing pressure response to changes in mean arterial pressure. Physiol Meas 2024; 45:065006. [PMID: 38838702 DOI: 10.1088/1361-6579/ad548d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Accepted: 06/05/2024] [Indexed: 06/07/2024]
Abstract
Objective. Cerebral critical closing pressure (CrCP) represents the value of arterial blood pressure (BP) where cerebral blood flow (CBF) becomes zero. Its dynamic response to a step change in mean BP (MAP) has been shown to reflect CBF autoregulation, but robust methods for its estimation are lacking. We aim to improve the quality of estimates of the CrCP dynamic response.Approach. Retrospective analysis of 437 healthy subjects (aged 18-87 years, 218 males) baseline recordings with measurements of cerebral blood velocity in the middle cerebral artery (MCAv, transcranial Doppler), non-invasive arterial BP (Finometer) and end-tidal CO2(EtCO2, capnography). For each cardiac cycle CrCP was estimated from the instantaneous MCAv-BP relationship. Transfer function analysis of the MAP and MCAv (MAP-MCAv) and CrCP (MAP-CrCP) allowed estimation of the corresponding step responses (SR) to changes in MAP, with the output in MCAv (SRVMCAv) representing the autoregulation index (ARI), ranging from 0 to 9. Four main parameters were considered as potential determinants of the SRVCrCPtemporal pattern, including the coherence function, MAP spectral power and the reconstruction error for SRVMAP, from the other three separate SRs.Main results. The reconstruction error for SRVMAPwas the main determinant of SRVCrCPsignal quality, by removing the largest number of outliers (Grubbs test) compared to the other three parameters. SRVCrCPshowed highly significant (p< 0.001) changes with time, but its amplitude or temporal pattern was not influenced by sex or age. The main physiological determinants of SRVCrCPwere the ARI and the mean CrCP for the entire 5 min baseline period. The early phase (2-3 s) of SRVCrCPresponse was influenced by heart rate whereas the late phase (10-14 s) was influenced by diastolic BP.Significance. These results should allow better planning and quality of future research and clinical trials of novel metrics of CBF regulation.
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Affiliation(s)
- Ronney B Panerai
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM), Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- NIHR Leicester Biomedical Research Centre, BHF Cardiovascular Research Centre, Glenfield Hospital, Leicester, United Kingdom
| | - Abdulaziz Alshehri
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM), Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- College of Applied Medical Sciences, University of Najran, Najran, Saudi Arabia
| | - Lucy C Beishon
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM), Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- NIHR Leicester Biomedical Research Centre, BHF Cardiovascular Research Centre, Glenfield Hospital, Leicester, United Kingdom
| | - Aaron Davies
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM), Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
| | - Victoria J Haunton
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM), Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
| | - Emmanuel Katsogridakis
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM), Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
| | - Man Y Lam
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM), Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
| | - Osian Llwyd
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM), Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- Wolfson Centre for Prevention of Stroke and Dementia, Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Thompson G Robinson
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM), Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- NIHR Leicester Biomedical Research Centre, BHF Cardiovascular Research Centre, Glenfield Hospital, Leicester, United Kingdom
| | - Jatinder S Minhas
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM), Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- NIHR Leicester Biomedical Research Centre, BHF Cardiovascular Research Centre, Glenfield Hospital, Leicester, United Kingdom
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Brasil S, de Carvalho Nogueira R, Salinet ÂSM, Yoshikawa MH, Teixeira MJ, Paiva W, Malbouisson LMS, Bor-Seng-Shu E, Panerai RB. Critical Closing Pressure and Cerebrovascular Resistance Responses to Intracranial Pressure Variations in Neurocritical Patients. Neurocrit Care 2023; 39:399-410. [PMID: 36869208 PMCID: PMC10541829 DOI: 10.1007/s12028-023-01691-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 01/31/2023] [Indexed: 03/05/2023]
Abstract
BACKGROUND Critical closing pressure (CrCP) and resistance-area product (RAP) have been conceived as compasses to optimize cerebral perfusion pressure (CPP) and monitor cerebrovascular resistance, respectively. However, for patients with acute brain injury (ABI), the impact of intracranial pressure (ICP) variability on these variables is poorly understood. The present study evaluates the effects of a controlled ICP variation on CrCP and RAP among patients with ABI. METHODS Consecutive neurocritical patients with ICP monitoring were included along with transcranial Doppler and invasive arterial blood pressure monitoring. Internal jugular veins compression was performed for 60 s for the elevation of intracranial blood volume and ICP. Patients were separated in groups according to previous intracranial hypertension severity, with either no skull opening (Sk1), neurosurgical mass lesions evacuation, or decompressive craniectomy (DC) (patients with DC [Sk3]). RESULTS Among 98 included patients, the correlation between change (Δ) in ICP and the corresponding ΔCrCP was strong (group Sk1 r = 0.643 [p = 0.0007], group with neurosurgical mass lesions evacuation r = 0.732 [p < 0.0001], and group Sk3 r = 0.580 [p = 0.003], respectively). Patients from group Sk3 presented a significantly higher ΔRAP (p = 0.005); however, for this group, a higher response in mean arterial pressure (change in mean arterial pressure p = 0.034) was observed. Exclusively, group Sk1 disclosed reduction in ICP before internal jugular veins compression withholding. CONCLUSIONS This study elucidates that CrCP reliably changes in accordance with ICP, being useful to indicate ideal CPP in neurocritical settings. In the early days after DC, cerebrovascular resistance seems to remain elevated, despite exacerbated arterial blood pressure responses in efforts to maintain CPP stable. Patients with ABI with no need of surgical procedures appear to remain with more effective ICP compensatory mechanisms when compared with those who underwent neurosurgical interventions.
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Affiliation(s)
- Sérgio Brasil
- Division of Neurosurgery, Department of Neurology, School of Medicine, University of São Paulo, Av. Dr. Eneas de Carvalho Aguiar 255, São Paulo, Brazil.
| | - Ricardo de Carvalho Nogueira
- Division of Neurosurgery, Department of Neurology, School of Medicine, University of São Paulo, Av. Dr. Eneas de Carvalho Aguiar 255, São Paulo, Brazil
| | - Ângela Salomão Macedo Salinet
- Division of Neurosurgery, Department of Neurology, School of Medicine, University of São Paulo, Av. Dr. Eneas de Carvalho Aguiar 255, São Paulo, Brazil
| | - Márcia Harumy Yoshikawa
- Division of Neurosurgery, Department of Neurology, School of Medicine, University of São Paulo, Av. Dr. Eneas de Carvalho Aguiar 255, São Paulo, Brazil
| | - Manoel Jacobsen Teixeira
- Division of Neurosurgery, Department of Neurology, School of Medicine, University of São Paulo, Av. Dr. Eneas de Carvalho Aguiar 255, São Paulo, Brazil
| | - Wellingson Paiva
- Division of Neurosurgery, Department of Neurology, School of Medicine, University of São Paulo, Av. Dr. Eneas de Carvalho Aguiar 255, São Paulo, Brazil
| | | | - Edson Bor-Seng-Shu
- Division of Neurosurgery, Department of Neurology, School of Medicine, University of São Paulo, Av. Dr. Eneas de Carvalho Aguiar 255, São Paulo, Brazil
| | - Ronney B Panerai
- Department of Cardiovascular Sciences, School of Life Sciences, University of Leicester, Leicester, UK
- National Institute for Health and Care Research, Cardiovascular Research Centre, Glenfield Hospital, University of Leicester, Leicester, UK
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6
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Panerai RB, Barnes SC, Batterham AP, Robinson TG, Haunton VJ. Directional sensitivity of dynamic cerebral autoregulation during spontaneous fluctuations in arterial blood pressure at rest. J Cereb Blood Flow Metab 2023; 43:552-564. [PMID: 36420777 PMCID: PMC10063834 DOI: 10.1177/0271678x221142527] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Directional sensitivity, the more efficient response of cerebral autoregulation to increases, compared to decreases, in mean arterial pressure (MAP), has been demonstrated with repeated squat-stand maneuvers (SSM). In 43 healthy subjects (26 male, 23.1 ± 4.2 years old), five min. recordings of cerebral blood velocity (bilateral Doppler ultrasound), MAP (Finometer), end-tidal CO2 (capnograph), and heart rate (ECG) were obtained during sitting (SIT), standing (STA) and SSM. A new analytical procedure, based on autoregressive-moving average models, allowed distinct estimates of the autoregulation index (ARI) by separating the MAP signal into its positive (MAP+D) and negative (MAP-D) derivatives. ARI+D was higher than ARI-D (p < 0.0001), SIT: 5.61 ± 1.58 vs 4.31 ± 2.16; STA: 5.70 ± 1.24 vs 4.63 ± 1.92; SSM: 4.70 ± 1.11 vs 3.31 ± 1.53, but the difference ARI+D-ARI-D was not influenced by the condition. A bootstrap procedure determined the critical number of subjects needed to identify a significant difference between ARI+D and ARI-D, corresponding to 24, 37 and 38 subjects, respectively, for SSM, STA and SIT. Further investigations are needed on the influences of sex, aging and other phenotypical characteristics on the phenomenon of directional sensitivity of dynamic autoregulation.
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Affiliation(s)
- Ronney B Panerai
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK.,NIHR Leicester Biomedical Research Centre, BHF Cardiovascular Research Centre, Glenfield Hospital, Leicester, UK
| | - Sam C Barnes
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
| | - Angus P Batterham
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
| | - Thompson G Robinson
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK.,NIHR Leicester Biomedical Research Centre, BHF Cardiovascular Research Centre, Glenfield Hospital, Leicester, UK
| | - Victoria J Haunton
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK.,NIHR Leicester Biomedical Research Centre, BHF Cardiovascular Research Centre, Glenfield Hospital, Leicester, UK
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7
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Brasil S, Nogueira RC, Salinet ASM, Yoshikawa MH, Teixeira MJ, Paiva W, Malbouisson LMS, Bor-Seng-Shu E, Panerai RB. Contribution of intracranial pressure to human dynamic cerebral autoregulation after acute brain injury. Am J Physiol Regul Integr Comp Physiol 2023; 324:R216-R226. [PMID: 36572556 DOI: 10.1152/ajpregu.00252.2022] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Cerebral perfusion pressure (CPP) is normally expressed by the difference between mean arterial blood pressure (MAP) and intracranial pressure (ICP) but comparison of the separate contributions of MAP and ICP to human cerebral blood flow autoregulation has not been reported. In patients with acute brain injury (ABI), internal jugular vein compression (IJVC) was performed for 60 s. Dynamic cerebral autoregulation (dCA) was assessed in recordings of middle cerebral artery blood velocity (MCAv, transcranial Doppler), and invasive measurements of MAP and ICP. Patients were separated according to injury severity as having whole/undamaged skull, large fractures, or craniotomies, or following decompressive craniectomy. Glasgow coma score was not different for the three groups. IJVC induced changes in MCAv, MAP, ICP, and CPP in all three groups. The MCAv response to step changes in MAP and ICP expressed the dCA response to these two inputs and was quantified with the autoregulation index (ARI). In 85 patients, ARI was lower for the ICP input as compared with the MAP input (2.25 ± 2.46 vs. 3.39 ± 2.28; P < 0.0001), and particularly depressed in the decompressive craniectomy (DC) group (n = 24, 0.35 ± 0.62 vs. 2.21 ± 1.96; P < 0.0005). In patients with ABI, the dCA response to changes in ICP is less efficient than corresponding responses to MAP changes. These results should be taken into consideration in studies aimed to optimize dCA by manipulation of CPP in neurocritical patients.
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Affiliation(s)
- Sérgio Brasil
- Department of Neurology, School of Medicine University of São Paulo, Brazil
| | - Ricardo C Nogueira
- Department of Neurology, School of Medicine University of São Paulo, Brazil
| | - Angela S M Salinet
- Department of Neurology, School of Medicine University of São Paulo, Brazil
| | - Márcia H Yoshikawa
- Department of Neurology, School of Medicine University of São Paulo, Brazil
| | - Manoel J Teixeira
- Department of Neurology, School of Medicine University of São Paulo, Brazil
| | - Wellingson Paiva
- Department of Neurology, School of Medicine University of São Paulo, Brazil
| | - Luiz M S Malbouisson
- Department of Intensive Care, School of Medicine University of São Paulo, Brazil
| | | | - Ronney B Panerai
- Cardiovascular Sciences Department, University of Leicester, United Kingdom.,National Institute for Health and Care Research, Cardiovascular Research Centre, Glenfield Hospital, University of Leicester, United Kingdom
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8
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Panerai RB, Brassard P, Burma JS, Castro P, Claassen JA, van Lieshout JJ, Liu J, Lucas SJ, Minhas JS, Mitsis GD, Nogueira RC, Ogoh S, Payne SJ, Rickards CA, Robertson AD, Rodrigues GD, Smirl JD, Simpson DM. Transfer function analysis of dynamic cerebral autoregulation: A CARNet white paper 2022 update. J Cereb Blood Flow Metab 2023; 43:3-25. [PMID: 35962478 PMCID: PMC9875346 DOI: 10.1177/0271678x221119760] [Citation(s) in RCA: 54] [Impact Index Per Article: 54.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Cerebral autoregulation (CA) refers to the control of cerebral tissue blood flow (CBF) in response to changes in perfusion pressure. Due to the challenges of measuring intracranial pressure, CA is often described as the relationship between mean arterial pressure (MAP) and CBF. Dynamic CA (dCA) can be assessed using multiple techniques, with transfer function analysis (TFA) being the most common. A 2016 white paper by members of an international Cerebrovascular Research Network (CARNet) that is focused on CA strove to improve TFA standardization by way of introducing data acquisition, analysis, and reporting guidelines. Since then, additional evidence has allowed for the improvement and refinement of the original recommendations, as well as for the inclusion of new guidelines to reflect recent advances in the field. This second edition of the white paper contains more robust, evidence-based recommendations, which have been expanded to address current streams of inquiry, including optimizing MAP variability, acquiring CBF estimates from alternative methods, estimating alternative dCA metrics, and incorporating dCA quantification into clinical trials. Implementation of these new and revised recommendations is important to improve the reliability and reproducibility of dCA studies, and to facilitate inter-institutional collaboration and the comparison of results between studies.
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Affiliation(s)
- Ronney B Panerai
- Department of Cardiovascular Sciences, University of Leicester and NIHR Biomedical Research Centre, Leicester, UK
| | - Patrice Brassard
- Department of Kinesiology, Faculty of Medicine, and Research Center of the Institut universitaire de cardiologie et de pneumologie de Québec, Université Laval, Québec, QC, Canada
| | - Joel S Burma
- Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
| | - Pedro Castro
- Department of Neurology, Centro Hospitalar Universitário de São João, Faculty of Medicine, University of Porto, Porto, Portugal
| | - Jurgen Ahr Claassen
- Department of Geriatric Medicine and Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - Johannes J van Lieshout
- Department of Internal Medicine, Amsterdam, UMC, The Netherlands and Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham Medical School, Queen's Medical Centre, UK
| | - Jia Liu
- Institute of Advanced Computing and Digital Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen University Town, Shenzhen, China
| | - Samuel Je Lucas
- School of Sport, Exercise and Rehabilitation Sciences and Centre for Human Brain Health, University of Birmingham, Birmingham, UK
| | - Jatinder S Minhas
- Department of Cardiovascular Sciences, University of Leicester and NIHR Biomedical Research Centre, Leicester, UK
| | - Georgios D Mitsis
- Department of Bioengineering, McGill University, Montreal, Québec, QC, Canada
| | - Ricardo C Nogueira
- Neurology Department, School of Medicine, Hospital das Clinicas, University of São Paulo, São Paulo, Brazil
| | - Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan
| | - Stephen J Payne
- Institute of Applied Mechanics, National Taiwan University, Taipei
| | - Caroline A Rickards
- Department of Physiology & Anatomy, University of North Texas Health Science Center, Fort Worth, Texas, USA
| | - Andrew D Robertson
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, ON, Canada
| | - Gabriel D Rodrigues
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Jonathan D Smirl
- Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
| | - David M Simpson
- Institute of Sound and Vibration Research, University of Southampton, Southampton, UK
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9
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Ladthavorlaphatt K, Surti FBS, Beishon LC, Panerai RB, Robinson TG. Challenging neurovascular coupling through complex and variable duration cognitive paradigms: A subcomponent analysis. Med Eng Phys 2022; 110:103921. [PMID: 36564144 DOI: 10.1016/j.medengphy.2022.103921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 10/04/2022] [Accepted: 11/09/2022] [Indexed: 11/13/2022]
Abstract
A similar pattern of cerebral blood velocity (CBv) response has been observed for neurovascular coupling (NVC) assessment with cognitive tasks of varying complexity and duration. This lack of specificity could result from parallel changes in arterial blood pressure (BP) and PaCO2, which could confound the estimates of NVC integrity. Healthy participants (n = 16) underwent recordings at rest (5 min sitting) and during randomized paradigms of different complexity (naming words (NW) beginning with P-, R-, V- words and serial subtractions (SS) of 100-2, 100-7, 1000-17, with durations of 5, 30 and 60 s). Bilateral CBv (middle cerebral arteries, transcranial Doppler), end-tidal CO2 (EtCO2, capnography), blood pressure (BP, Finapres) and heart rate (HR, ECG) were recorded continuously. The bilateral CBv response to all paradigms was classified under objective criteria to select only responders, then the repeated data were averaged between visits. Bilateral CBv change to tasks was decomposed into the relative contributions (subcomponents) of arterial BP (VBP; neurogenic), critical closing pressure (VCrCP; metabolic) and resistance area product (VRAP; myogenic). A temporal effect was demonstrated in bilateral VBP and VRAP during all tasks (p<0.002), increased VBP early (between 0 and 10 s) and followed by decreases of VRAP late (25-35 s) in the response. VCrCP varied by complexity and duration (p<0.046). The main contributions to CBv responses to cognitive tasks of different complexity and duration were VBP and VRAP, whilst a smaller contribution from VCrCP would suggest sensitivity to metabolic demands. Further studies are needed to assess the influence of different paradigms, ageing and cerebrovascular conditions.
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Affiliation(s)
- Kannaphob Ladthavorlaphatt
- Department of Cardiovascular Sciences, College of Life Sciences, Leicester Royal Infirmary, University of Leicester, Level 4, Robert Kilpatrick Clinical Sciences Building, Leicester LE2 7LX, United Kingdom; Medical Diagnostics Unit, Thammasat University Hospital, Thammasat University, Pathumthani, Thailand.
| | - Farhaana B S Surti
- Department of Cardiovascular Sciences, College of Life Sciences, Leicester Royal Infirmary, University of Leicester, Level 4, Robert Kilpatrick Clinical Sciences Building, Leicester LE2 7LX, United Kingdom
| | - Lucy C Beishon
- Department of Cardiovascular Sciences, College of Life Sciences, Leicester Royal Infirmary, University of Leicester, Level 4, Robert Kilpatrick Clinical Sciences Building, Leicester LE2 7LX, United Kingdom; NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, United Kingdom
| | - Ronney B Panerai
- Department of Cardiovascular Sciences, College of Life Sciences, Leicester Royal Infirmary, University of Leicester, Level 4, Robert Kilpatrick Clinical Sciences Building, Leicester LE2 7LX, United Kingdom; NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, United Kingdom
| | - Thompson G Robinson
- Department of Cardiovascular Sciences, College of Life Sciences, Leicester Royal Infirmary, University of Leicester, Level 4, Robert Kilpatrick Clinical Sciences Building, Leicester LE2 7LX, United Kingdom; NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, United Kingdom
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10
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Barnes SC, Panerai RB, Beishon L, Hanby M, Robinson TG, Haunton VJ. Cerebrovascular responses to somatomotor stimulation in Parkinson's disease: A multivariate analysis. J Cereb Blood Flow Metab 2022; 42:1547-1558. [PMID: 35287495 PMCID: PMC9274867 DOI: 10.1177/0271678x211065204] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Parkinson's disease (PD) is a common neurodegenerative disorder, yet little is known about cerebral haemodynamics in this patient population. Previous studies assessing dynamic cerebral autoregulation (dCA), neurovascular coupling (NVC) and vasomotor reactivity (VMR) have yielded conflicting findings. By using multi-variate modelling, we aimed to determine whether cerebral blood flow (CBF) regulation is impaired in PD patients.55 healthy controls (HC) and 49 PD patients were recruited. PD subjects underwent a second recording following a period of abstinence from their anti-Parkinsonian medication. Continuous bilateral transcranial Doppler in the middle cerebral arteries, beat-to-beat mean arterial blood pressure (MAP; Finapres), heart rate (HR; electrocardiogram), and end-tidal CO2 (EtCO2; capnography) were measured. After a 5-min baseline period, a passive motor paradigm comprising 60 s of elbow flexion was performed. Multi-variate modelling quantified the contributions of MAP, ETCO2 and neural stimulation to changes in CBF velocity (CBFV). dCA, VMR and NVC were quantified to assess the integrity of CBF regulation.Neural stimulation was the dominant input. dCA, NVC and VMR were all found to be impaired in the PD population relative to HC (p < 0.01, p = 0.04, p < 0.01, respectively). Our data suggest PD may be associated with depressed CBF regulation. This warrants further assessment using different neural stimuli.
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Affiliation(s)
- Sam C Barnes
- Department of Cardiovascular Sciences, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester, UK
| | - Ronney B Panerai
- Department of Cardiovascular Sciences, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester, UK.,NIHR Leicester Biomedical Research Centre, BHF Cardiovascular Research Centre, Glenfield Hospital, Leicester, UK
| | - Lucy Beishon
- Department of Cardiovascular Sciences, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester, UK.,NIHR Leicester Biomedical Research Centre, BHF Cardiovascular Research Centre, Glenfield Hospital, Leicester, UK
| | - Martha Hanby
- Department of Cardiovascular Sciences, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester, UK
| | - Thompson G Robinson
- Department of Cardiovascular Sciences, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester, UK.,NIHR Leicester Biomedical Research Centre, BHF Cardiovascular Research Centre, Glenfield Hospital, Leicester, UK
| | - Victoria J Haunton
- Department of Cardiovascular Sciences, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester, UK.,NIHR Leicester Biomedical Research Centre, BHF Cardiovascular Research Centre, Glenfield Hospital, Leicester, UK
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11
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Castro P, Freitas J, Azevedo E, Tan CO. Cerebrovascular regulation in patients with vasovagal syncope and autonomic failure due to familial amyloidotic polyneuropathy. Auton Neurosci 2022; 242:103010. [PMID: 35907336 DOI: 10.1016/j.autneu.2022.103010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 05/10/2022] [Accepted: 07/03/2022] [Indexed: 11/16/2022]
Abstract
INTRODUCTION While there is strong evidence for autonomic involvement in cerebrovascular function acutely, long-term role of autonomic nervous system in cerebrovascular function has been controversial. We assessed autoregulation in 10 healthy individuals, nine patients with vasovagal syncope (VVS), and nine with Familial Amyloidotic Polyneuropathy (FAP), in response to head-up tilt test (HUTT). METHODS Arterial blood pressure heart rate, cardiac output, and bilateral cerebral blood flow velocity (CBFV) at the M1 segment of middle cerebral artery (transcranial Doppler ultrasound) were recorded during supine rest and 70° HUTT. Autoregulation was quantified using a validated nonlinear and nonparametric approach based on projection pursuit regression. Plasma adrenaline and noradrenaline were also measured at rest and during HUTT. RESULTS During supine rest and HUTT, plasma noradrenaline content was lower in FAP patients. During HUTT, VVS patients had a hyperadrenergic status; CBFV decreased in all groups, which was greater in FAP patients (p < 0.01). Healthy controls responded to HUTT with a reduction in CBFV responses to increases (p = 0.01) and decreases (p < 0.01) in arterial pressure without any change in the range or effectiveness of autoregulation. VVS patients responded to HUTT with a reduction in falling (p = 0.02), but not rising slope (p = 0.40). Autoregulatory range (p < 0.01) and effectiveness increased (p = 0.09), consistent with the rapid increase in levels of catecholamines. In FAP patients, the level of increase in range of autoregulation was significantly related to the magnitude of increase in plasma noradrenaline in response to HUTT (R2 = 0.26, p = 0.05). CONCLUSION Autonomic dysfunction affects the cerebral autoregulatory response orthostatic to challenge.
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Affiliation(s)
- Pedro Castro
- Department of Neurology, Centro Hospitalar Universitário São João, Cardiovascular R&D Unit, Faculty of Medicine of University of Porto, Porto, Portugal.
| | - João Freitas
- Autonomic Unit, São João Hospital Center, Faculty of Medicine of University of Porto, Porto, Portugal
| | - Elsa Azevedo
- Department of Neurology, Centro Hospitalar Universitário São João, Cardiovascular R&D Unit, Faculty of Medicine of University of Porto, Porto, Portugal.
| | - Can Ozan Tan
- Cerebrovascular Research Laboratory and Department of Physical Medicine and Rehabilitation, Harvard Medical School, Spaulding Rehabilitation Hospital, Boston, MA, US.
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12
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Liang Y, Mo P, Yang X, He Y, Zhang W, Zeng X, Xie L, Gao Q. Estimation of critical closing pressure using intravascular blood pressure of the common carotid artery. Med Eng Phys 2022; 102:103759. [DOI: 10.1016/j.medengphy.2022.103759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 01/01/2022] [Accepted: 01/14/2022] [Indexed: 10/19/2022]
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13
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Panerai RB, Haunton VJ, Llwyd O, Minhas JS, Katsogridakis E, Salinet ASM, Maggio P, Robinson TG. Cerebral critical closing pressure and resistance-area product: the influence of dynamic cerebral autoregulation, age and sex. J Cereb Blood Flow Metab 2021; 41:2456-2469. [PMID: 33818187 PMCID: PMC8392773 DOI: 10.1177/0271678x211004131] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 01/19/2021] [Accepted: 02/16/2021] [Indexed: 11/21/2022]
Abstract
Instantaneous arterial pressure-flow (or velocity) relationships indicate the existence of a cerebral critical closing pressure (CrCP), with the slope of the relationship expressed by the resistance-area product (RAP). In 194 healthy subjects (20-82 years, 90 female), cerebral blood flow velocity (CBFV, transcranial Doppler), arterial blood pressure (BP, Finapres) and end-tidal CO2 (EtCO2, capnography) were measured continuously for five minutes during spontaneous fluctuations of BP at rest. The dynamic cerebral autoregulation (CA) index (ARI) was extracted with transfer function analysis from the CBFV step response to the BP input and step responses were also obtained for the BP-CrCP and BP-RAP relationships. ARI was shown to decrease with age at a rate of -0.025 units/year in men (p = 0.022), but not in women (p = 0.40). The temporal patterns of the BP-CBFV, BP-CrCP and BP-RAP step responses were strongly influenced by the ARI (p < 0.0001), but not by sex. Age was also a significant determinant of the peak of the CBFV step response and the tail of the RAP response. Whilst the RAP step response pattern is consistent with a myogenic mechanism controlling dynamic CA, further work is needed to explore the potential association of the CrCP step response with the flow-mediated component of autoregulation.
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Affiliation(s)
- Ronney B Panerai
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
- NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, UK
| | - Victoria J Haunton
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
- NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, UK
| | - Osian Llwyd
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
| | - Jatinder S Minhas
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
- NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, UK
| | - Emmanuel Katsogridakis
- Department of Vascular Surgery, Wythenshawe Hospital, Manchester Foundation Trust, Manchester, UK
| | - Angela SM Salinet
- Neurology Department, Hospital das Clinicas, School of Medicine, University of Sao Paulo, Sao Paulo, Brazil
| | - Paola Maggio
- Neurology Department, ASST Bergamo EST (BG), Italy
| | - Thompson G Robinson
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
- NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, UK
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14
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Robles FAB, Panerai RB, Katsogridakis E, Chacon M. Superior fitting of arterial resistance and compliance parameters with genetic algorithms in models of dynamic cerebral autoregulation. IEEE Trans Biomed Eng 2021; 69:503-512. [PMID: 34314353 DOI: 10.1109/tbme.2021.3100288] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVE The capacity of discriminating between normal and impaired dynamic cerebral autoregulation (dCA), based on spontaneous fluctuations in arterial blood pressure (ABP) and cerebral blood flow (CBF), has considerable clinical relevance. This study aimed to quantify the separate contributions of vascular resistance and compliance as parameters that could reflect myogenic and metabolic mechanisms to dCA. METHODS Forty-five subjects were studied under normo and hypercapnic conditions induced by breathing a mixture of 5% carbon dioxide in air. Dynamic cerebrovascular resistance and compliance models with ABP as input and CBFV as output were fitted using Genetic Algorithms to identify parameter values for each subject, and respiratory condition. RESULTS The efficiency of dCA was assessed from the models generated CBFV response to an ABP step change, corresponding to an autoregulation index of 5.561.57 in normocapnia and 2.381.73 in hypercapnia, with an area under the ROC curve (AUC) of 0.9 between both conditions. Vascular compliance increased from 0.750.7 ml/mmHg in normocapnia to 5.8212.0 ml/mmHg during hypercapnia, with an AUC of 0.88. CONCLUSION we demonstrated that Genetic Algorithms are a powerful tool to provide accurate identification of model parameters expressing the performance of human CA Significance: Further work is needed to validate this approach in clinical applications where individualised model parameters could provide relevant diagnostic and prognostic information about dCA impairment Index Terms arterial compliance, autoregulation impairment, cerebral blood flow, Genetic Algorithms, hypercapnia.
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15
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Panerai RB, Batterham A, Robinson TG, Haunton VJ. Determinants of cerebral blood flow velocity change during squat-stand maneuvers. Am J Physiol Regul Integr Comp Physiol 2021; 320:R452-R466. [PMID: 33533312 DOI: 10.1152/ajpregu.00291.2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The large changes in mean arterial blood pressure (MABP) and cerebral blood flow velocity (CBFV) induced by squat-stand maneuvers (SSM) make this approach particularly suited for studying dynamic cerebral autoregulation (CA). However, the role of other systemic determinants of CBFV has not been described and could provide alternative physiological interpretations of SSM results. In 32 healthy subjects (16 female), continuous recordings of MABP (Finometer), bilateral CBFV (transcranial Doppler, MCA), end-tidal CO2 (EtCO2; capnography), and heart rate (HR; electrocardiogram) were performed for 5 min standing at rest, and during 15 SSM at the frequency of 0.05 Hz. A time-domain, multivariate dynamic model estimated the CBFV variance explained by different inputs, corresponding to significant contributions from MABP (P < 0.00001), EtCO2 (P < 0.0001), and HR (P = 0.041). The autoregulation index (ARI; range 0-9) was estimated from the CBFV response to a step change in MABP. At rest, ARI values (typically 5.7) were independent of the number of model inputs, but during SSM, ARI was reduced compared with baseline (P < 0.0001), and the three input model yielded lower values for the right and left MCA (3.4 ± 1.2, 3.1 ± 1.3) when compared with the single-input MABP-CBFV model (4.1 ± 1.1, 3.9 ± 1.0; P < 0.0001). The high coherence of the MABP-CBFV transfer function at 0.05 Hz (typically 0.98) was considerably reduced (around 0.71-0.73; P < 0.0001) when the contribution of CBFV covariates was taken into account. Not taking into consideration other determinants of CBFV, in addition to MABP, could be misleading and introduce biases in physiological and clinical studies.
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Affiliation(s)
- Ronney B Panerai
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom.,National Institute for Health Research Leicester Biomedical Research Centre, University of Leicester, Leicester, United Kingdom
| | - Angus Batterham
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
| | - Thompson G Robinson
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom.,National Institute for Health Research Leicester Biomedical Research Centre, University of Leicester, Leicester, United Kingdom
| | - Victoria J Haunton
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom.,National Institute for Health Research Leicester Biomedical Research Centre, University of Leicester, Leicester, United Kingdom
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16
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Trofimova KA, Agarkova DI, Trofimov AO, Abashkin AY, Bragin DE. Cerebral Critical Closing Pressure in Concomitant Traumatic Brain Injury and Intracranial Hematomas. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1339:33-38. [PMID: 35023087 PMCID: PMC9131855 DOI: 10.1007/978-3-030-78787-5_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The critical closing pressure (CrCP) is the pressure below which the local pial blood pressure is inadequate to prevent blood flow cessation. The cerebral CrCP in concomitant traumatic brain injury (TBI) and intracranial hematomas (TBI + ICH) remains understudied. The aim was to determine the status of the CrCP at сTBI with and without the ICH development. MATERIAL AND METHODS The results of the treatment of 90 patients with severe to moderate сTBI were studied (male/female - 49:41). The average age was 34.2 ± 14.4 years. Depending on the presence of ICH, patients were divided into two groups. All patients were subjected to transcranial Doppler of the both middle cerebral arteries, and evaluation of mean arterial pressure (MAP). Based on data obtained, the CrCPs were calculated. Significance was preset to p < 0.05. RESULTS The mean CrCP values in each group appeared to be significantly higher than a referral value (р < 0.05). The mean CrCP values in the perifocal zone of removed hematoma were significantly higher than in TBI patients without ICH (р = 0.015 and р = 0.048, respectively). Analysis of CrCP values in various types of ICH showed no statistically significant differences (р > 0.05). DISCUSSION The CrCP significantly differs in the groups of TBI patients with and without ICH. The comparability of the groups in respect to the concomitant injury structure proves that the revealed CrCP changes result from the traumatic compression of the brain.
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Affiliation(s)
- Kseniia A Trofimova
- Department of Neurosurgery, Privolzhsky Research Medical University, Nizhny Novgorod, Russia
| | - Darya I Agarkova
- Department of Neurosurgery, Regional Hospital named after Semashko, Nizhny Novgorod, Russia
| | - Alex O Trofimov
- Department of Neurosurgery, Privolzhsky Research Medical University, Nizhny Novgorod, Russia.
- Department of Neurosurgery, Regional Hospital named after Semashko, Nizhny Novgorod, Russia.
| | - Andrew Y Abashkin
- Department of Neurosurgery, Regional Hospital named after Semashko, Nizhny Novgorod, Russia
| | - Denis E Bragin
- Lovelace Biomedical Research Institute, Albuquerque, NM, USA
- Department of Neurosurgery, University of New Mexico School of Medicine, Albuquerque, NM, USA
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17
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Egger ST, Bobes J, Rauen K, Seifritz E, Vetter S, Schuepbach D. Psychopathological Symptom Load and Distinguishable Cerebral Blood Flow Velocity Patterns in Patients With Schizophrenia and Healthy Controls: A Functional Transcranial Doppler Study. Front Psychiatry 2021; 12:679021. [PMID: 34248715 PMCID: PMC8267584 DOI: 10.3389/fpsyt.2021.679021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 05/21/2021] [Indexed: 01/03/2023] Open
Abstract
Introduction: Schizophrenia is a severe psychiatric disorder, with executive dysfunction and impaired processing speed playing a pivotal role in the course of the disease. In patients with schizophrenia, neurocognitive deficits appear to be related to alterations in cerebral hemodynamics. It is not fully understood if psychopathological symptom load (i.e., presence and severity of symptoms) is also related to alterations in cerebral hemodynamics. We aim to study the relationship between psychopathological symptom load and cerebral hemodynamics in the Middle Cerebral Artery (MCA) during a cognitive task in patients with schizophrenia and healthy controls. Methodology: Cerebral hemodynamics in the MCA were examined in 30 patients with schizophrenia and 15 healthy controls using functional Transcranial Doppler (fTCD) during the Trail Making Test (TMT). Psychopathological symptoms were measured using the Brief Psychiatric Rating Scale (BPRS). Patients were dichotomized according to BPRS scores: mild-moderate (BPRS < 41, n = 15) or marked-severe (BPRS ≧ 41, n = 15). Mean blood flow velocity (MFV) in the MCA and processing speed of the TMT were analyzed. Cerebral hemodynamics were analyzed using the general additional model (GAM) with a covariate analysis of variance (ANCOVA) for group comparisons. Results: Patients and healthy controls were comparable regarding demographics. Patients had a slower processing speed for the TMT-A (patients-severe: 52s, patients-moderate: 40s, healthy-controls: 32s, p = 0.019) and TMT-B [patients-severe: 111s, patients-moderate: 76s, healthy-controls: 66s, p < 0.001)]. Patients demonstrated differing hemodynamic profiles in both TMTs: TMT- A [F (6, 1,792) = 17, p < 0.000); TMT-B [F (6, 2,692) = 61.93, p < 0.000], with a delay in increase in MFV and a failure to return to baseline values. Conclusions: Patients with schizophrenia demonstrated slower speeds of processing during both the TMT-A and TMT-B. The speed of processing deteriorated with increasing psychopathological symptom load, additionally a distinct cerebral hemodynamic pattern in the MCA was observed. Our results further support the view that severity of schizophrenia, particularly psychopathological symptom load, influences performance in neurocognitive tasks and is related to distinct patterns of brain hemodynamics.
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Affiliation(s)
- Stephan T Egger
- Department of Psychiatry, Psychotherapy and Psychosomatics, Faculty of Medicine, University Hospital of Zurich, University of Zürich, Zurich, Switzerland.,Department of Psychiatry, Faculty of Medicine, University of Oviedo, Oviedo, Spain
| | - Julio Bobes
- Department of Psychiatry, Faculty of Medicine, University of Oviedo, Oviedo, Spain
| | - Katrin Rauen
- Department of Geriatric Psychiatry, Faculty of Medicine, Psychiatric University Hospital of Zurich, University of Zürich, Zurich, Switzerland.,Institute for Stroke and Dementia Research, Ludwig Maximilian University Munich, University Hospital, Munich, Germany
| | - Erich Seifritz
- Department of Psychiatry, Psychotherapy and Psychosomatics, Faculty of Medicine, University Hospital of Zurich, University of Zürich, Zurich, Switzerland
| | - Stefan Vetter
- Department of Psychiatry, Psychotherapy and Psychosomatics, Faculty of Medicine, University Hospital of Zurich, University of Zürich, Zurich, Switzerland
| | - Daniel Schuepbach
- Department of General Psychiatry, Center of Psychosocial Medicine, University of Heidelberg, Heidelberg, Germany.,Klinikum am Weissenhof, Weinsberg, Germany
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18
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Panerai RB, Minhas JS, Llwyd O, Salinet ASM, Katsogridakis E, Maggio P, Robinson TG. The critical closing pressure contribution to dynamic cerebral autoregulation in humans: influence of arterial partial pressure of CO 2. J Physiol 2020; 598:5673-5685. [PMID: 32975820 DOI: 10.1113/jp280439] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 09/16/2020] [Indexed: 03/07/2024] Open
Abstract
KEY POINTS Dynamic cerebral autoregulation (CA) is often expressed by the mean arterial blood pressure (MAP)-cerebral blood flow (CBF) relationship, with little attention given to the dynamic relationship between MAP and cerebrovascular resistance (CVR). In CBF velocity (CBFV) recordings with transcranial Doppler, evidence demonstrates that CVR should be replaced by a combination of a resistance-area product (RAP) with a critical closing pressure (CrCP) parameter, the blood pressure value where CBFV reaches zero due to vessels collapsing. Transfer function analysis of the MAP-CBFV relationship can be extended to the MAP-RAP and MAP-CrCP relationships, to assess their contribution to the dynamic CA response. During normocapnia, both RAP and CrCP make a significant contribution to explaining the MAP-CBFV relationship. Hypercapnia, a surrogate state of depressed CA, leads to marked changes in dynamic CA, that are entirely explained by the CrCP response, without further contribution from RAP in comparison with normocapnia. ABSTRACT Dynamic cerebral autoregulation (CA) is manifested by changes in the diameter of intra-cerebral vessels, which control cerebrovascular resistance (CVR). We investigated the contribution of critical closing pressure (CrCP), an important determinant of CVR, to explain the cerebral blood flow (CBF) response to a sudden change in mean arterial blood pressure (MAP). In 76 healthy subjects (age range 21-70 years, 36 women), recordings of MAP (Finometer), CBF velocity (CBFV; transcranial Doppler ultrasound), end-tidal CO2 (capnography) and heart rate (ECG) were performed for 5 min at rest (normocapnia) and during hypercapnia induced by breathing 5% CO2 in air. CrCP and the resistance-area product (RAP) were obtained for each cardiac cycle and their dynamic response to a step change in MAP was calculated by means of transfer function analysis. The recovery of the CBFV response, following a step change in MAP, was mainly due to the contribution of RAP during both breathing conditions. However, CrCP made a highly significant contribution during normocapnia (P < 0.0001) and was the sole determinant of changes in the CBFV response, resulting from hypercapnia, which led to a reduction in the autoregulation index from 5.70 ± 1.58 (normocapnia) to 4.14 ± 2.05 (hypercapnia; P < 0.0001). In conclusion, CrCP makes a very significant contribution to the dynamic CBFV response to changes in MAP and plays a major role in explaining the deterioration of dynamic CA induced by hypercapnia. Further studies are needed to assess the relevance of CrCP contribution in physiological and clinical studies.
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Affiliation(s)
- Ronney B Panerai
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
- NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, UK
| | - Jatinder S Minhas
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
- NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, UK
| | - Osian Llwyd
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
| | - Angela S M Salinet
- Neurology Department, Hospital das Clinicas, School of Medicine, University of Sao Paulo, Sao Paulo, Brazil
| | - Emmanuel Katsogridakis
- Department of Vascular Surgery, Wythenshawe Hospital, Manchester Foundation Trust, Manchester, UK
| | - Paola Maggio
- Neurology Department, ASST Bergamo EST (BG), Italy
| | - Thompson G Robinson
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
- NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, UK
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19
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Junejo RT, Braz ID, Lucas SJ, van Lieshout JJ, Phillips AA, Lip GY, Fisher JP. Neurovascular coupling and cerebral autoregulation in atrial fibrillation. J Cereb Blood Flow Metab 2020; 40:1647-1657. [PMID: 31426699 PMCID: PMC7370373 DOI: 10.1177/0271678x19870770] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The risk of cognitive decline and stroke is increased by atrial fibrillation (AF). We sought to determine whether neurovascular coupling and cerebral autoregulation are blunted in people with AF in comparison with age-matched, patients with hypertension and healthy controls. Neurovascular coupling was assessed using five cycles of visual stimulation for 30 s followed by 30 s with both eyes-closed. Cerebral autoregulation was examined using a sit-stand test, and a repeated squat-to-stand (0.1 Hz) manoeuvre with transfer function analysis of mean arterial pressure (MAP; input) and middle cerebral artery mean blood flow velocity (MCA Vm; output) relationships at 0.1 Hz. Visual stimulation increased posterior cerebral artery conductance, but the magnitude of the response was blunted in patients with AF (18 [8] %; mean [SD]) and hypertension (17 [8] %), in comparison with healthy controls (26 [9] %) (P < 0.05). In contrast, transmission of MAP to MCA Vm was greater in AF patients compared to hypertension and healthy controls, indicating diminished cerebral autoregulation. We have shown for the first time that AF patients have impaired neurovascular coupling responses to visual stimulation and diminished cerebral autoregulation. Such deficits in cerebrovascular regulation may contribute to the increased risk of cerebral dysfunction in people with AF.
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Affiliation(s)
- Rehan T Junejo
- School of Sport, Exercise & Rehabilitation Sciences, College of Life & Environmental Sciences, University of Birmingham, Birmingham, UK.,Liverpool Centre for Cardiovascular Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
| | - Igor D Braz
- Medical School, University Center of Volta Redonda, Volta Redonda, Brazil
| | - Samuel Je Lucas
- School of Sport, Exercise & Rehabilitation Sciences, College of Life & Environmental Sciences, University of Birmingham, Birmingham, UK.,Centre for Human Brain Health, College of Life & Environmental Sciences, University of Birmingham, Birmingham, UK
| | - Johannes J van Lieshout
- Department of Internal Medicine, University of Amsterdam, Amsterdam, The Netherlands.,Laboratory for Clinical Cardiovascular Physiology, AMC Center for Heart Failure Research, Academic Medical Center, University of Amsterdam, 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
| | - Aaron A Phillips
- Departments of Physiology, Pharmacology & Clinical Neurosciences, Libin Cardiovascular Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Alberta, Canada
| | - Gregory Yh Lip
- Liverpool Centre for Cardiovascular Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
| | - James P Fisher
- School of Sport, Exercise & Rehabilitation Sciences, College of Life & Environmental Sciences, University of Birmingham, Birmingham, UK.,Department of Physiology, Faculty of Medical & Health Sciences, University of Auckland, Auckland, New Zealand
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20
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An objective method to identify non-responders in neurovascular coupling testing. J Neurosci Methods 2020; 341:108779. [DOI: 10.1016/j.jneumeth.2020.108779] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 05/10/2020] [Accepted: 05/11/2020] [Indexed: 01/04/2023]
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21
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Washio T, Watanabe H, Ogoh S. Dynamic cerebral autoregulation in anterior and posterior cerebral circulation during cold pressor test. J Physiol Sci 2020; 70:1. [PMID: 32039699 PMCID: PMC6987085 DOI: 10.1186/s12576-020-00732-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 01/22/2020] [Indexed: 12/26/2022]
Abstract
We hypothesized that cerebral blood flow (CBF) regulation in the posterior circulation differs from that of the anterior circulation during a cold pressor test (CPT) and is accompanied by elevations in arterial blood pressure (ABP) and sympathetic nervous activity (SNA). To test this, dynamic cerebral autoregulation (dCA) in the middle and posterior cerebral arteries (MCA and PCA) were measured at three different conditions: control, early phase of the CPT, and the late phase of the CPT. The dCA was examined using a thigh cuff occlusion and release technique. The MCA and PCA blood velocities were unchanged at CPT compared with the control conditions despite an elevation in the ABP. The dCA in both the MCA and PCA remained unaltered at CPT. These findings suggest that CPT-induced elevations in the ABP and SNA did not cause changes in the CBF regulation in the posterior circulation compared with the anterior circulation.
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Affiliation(s)
- Takuro Washio
- Department of Biomedical Engineering, Toyo University, 2100 Kujirai, Kawagoe-shi, Saitama, 350-8585, Japan.,Research Fellow of Japan Society for the Promotion of Science, Tokyo, Japan
| | - Hironori Watanabe
- Department of Biomedical Engineering, Toyo University, 2100 Kujirai, Kawagoe-shi, Saitama, 350-8585, Japan
| | - Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, 2100 Kujirai, Kawagoe-shi, Saitama, 350-8585, Japan.
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22
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Müller M, Österreich M. Cerebrovascular Dynamics During Continuous Motor Task. Physiol Res 2019; 68:997-1004. [PMID: 31647292 DOI: 10.33549/physiolres.934147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
We investigated the cerebral autoregulation (CA) dynamics parameter phase and gain change when exposed to a longlasting motor task. 25 healthy subjects (mean age ± SE, 38±2.6 years, 13 females) underwent simultaneous recordings of spontaneous fluctuations in blood pressure (BP), cerebral blood flow velocity (CBFV), and end-tidal CO(2) (ETCO(2)) over 5 min of rest followed by 5 min of left elbow flexion at a frequency of 1 Hz. Tansfer function gain and phase between BP and CBFV were assessed in the frequency ranges of very low frequencies (VLF, 0.02-0.07 Hz), low frequencies (LF, 0.07-0.15), and high frequencies (HF, >0.15). CBFV increased on both sides rapidly to maintain an elevated steady state until movement stopped. Cerebrovascular resistance fell on the right side (rest 1.35±0.06, movement 1.28±0.06, p<0.01), LF gain decreased from baseline (right side 0.97±0.07 %/mm Hg, left 1.01±0.09) to movement epoch (right 0.73±0.08, left 0.76±0.06, p</=0.01). VLF phase decreased from baseline (right 1.03±0.05 radians, left 1.10±0.06) to the movement epoch (right 0.81±0.07, left 0.82±0.10, p?0.05). CA regulates continuous motor efforts by changes in resistance, gain and phase.
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Affiliation(s)
- M Müller
- Neurocenter, Neurovascular Laboratory, Lucerne Kantonsspital, Lucerne, Switzerland.
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23
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Panerai RB, Hanby MF, Robinson TG, Haunton VJ. Alternative representation of neural activation in multivariate models of neurovascular coupling in humans. J Neurophysiol 2019; 122:833-843. [DOI: 10.1152/jn.00175.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Neural stimulation leads to increases in cerebral blood flow (CBF), but simultaneous changes in covariates, such as arterial blood pressure (BP) and [Formula: see text], rule out the use of CBF changes as a reliable marker of neurovascular coupling (NVC) integrity. Healthy subjects performed repetitive (1 Hz) passive elbow flexion with their dominant arm for 60 s. CBF velocity (CBFV) was recorded bilaterally in the middle cerebral artery with transcranial Doppler, BP with the Finometer device, and end-tidal CO2 (EtCO2) with capnography. The simultaneous effects of neural stimulation, BP, and [Formula: see text] on CBFV were expressed with a dynamic multivariate model, using BP, EtCO2, and stimulation [ s( t)] as inputs. Two versions of s( t) were considered: a gate function [ sG( t)] or an orthogonal decomposition [ sO( t)] function. A separate CBFV step response was extracted from the model for each of the three inputs, providing estimates of dynamic cerebral autoregulation [CA; autoregulation index (ARI)], CO2 reactivity [vasomotor reactivity step response (VMRSR)], and NVC [stimulus step response (STIMSR)]. In 56 subjects, 224 model implementations produced excellent predictive CBFV correlation (median r = 0.995). Model-generated sO( t), for both dominant (DH) and nondominant (NDH) hemispheres, was highly significant during stimulation (<10−5) and was correlated with the CBFV change ( r = 0.73, P = 0.0001). The sO( t) explained a greater fraction of CBFV variance (~50%) than sG( t) (44%, P = 0.002). Most CBFV step responses to the three inputs were physiologically plausible, with better agreement for the CBFV-BP step response yielding ARI values of 7.3 for both DH and NDH for sG( t), and 6.9 and 7.4 for sO( t), respectively. No differences between DH and NDH were observed for VMRSR or STIMSR. A new procedure is proposed to represent the contribution from other aspects of CBF regulation than BP and CO2 in response to sensorimotor stimulation, as a tool for integrated, noninvasive, assessment of the multiple influences of dynamic CA, CO2 reactivity, and NVC in humans. NEW & NOTEWORTHY A new approach was proposed to identify the separate contributions of stimulation, arterial blood pressure (BP), and arterial CO2 ([Formula: see text]) to the cerebral blood flow (CBF) response observed in neurovascular coupling (NVC) studies in humans. Instead of adopting an empirical gate function to represent the stimulation input, a model-generated function is derived as part of the modeling process, providing a representation of the NVC response, independent of the contributions of BP or [Formula: see text]. This new marker of NVC, together with the model-predicted outputs for the contributions of BP, [Formula: see text] and stimulation, has considerable potential to both quantify and simultaneously integrate the separate mechanisms involved in CBF regulation, namely, cerebral autoregulation, CO2 reactivity and other contributions.
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Affiliation(s)
- Ronney B. Panerai
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- National Institute for Health Research Leicester Biomedical Research Centre, University of Leicester, Leicester, United Kingdom
| | - Martha F. Hanby
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
| | - Thompson G. Robinson
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- National Institute for Health Research Leicester Biomedical Research Centre, University of Leicester, Leicester, United Kingdom
| | - Victoria J. Haunton
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- National Institute for Health Research Leicester Biomedical Research Centre, University of Leicester, Leicester, United Kingdom
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24
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Zardi EM, Giorgi C, Zardi DM. Diagnostic approach to neuropsychiatric lupus erythematosus: what should we do? Postgrad Med 2018; 130:536-547. [PMID: 29940795 DOI: 10.1080/00325481.2018.1492309] [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] [Indexed: 02/08/2023]
Abstract
Neuropsychiatric systemic lupus erythematosus is a diagnostic challenge due to the multifarious neurological and psychiatric manifestations that define it but, when suspected, diagnostic imaging can give a fundamental help. The advancements and variety of neuroimaging techniques allow us to perform more and more accurate evaluations of structure, perfusion, and metabolism of the brain and to detect cerebral and spinal lesions. Moreover, vascular districts of the neck and the brain, as well as the electrical brain and peripheral muscle activity may be accurately investigated, thus giving us a wide panoramic view. Although magnetic resonance is recognized as a fundamental neuroimaging technique to reach a correct diagnosis, the juxtaposition of other diagnostic techniques has improved the possibility to make diagnoses but has also increased the confusion about deciding which of them to use and when. Our aim was to combine the number of available techniques with the need to simplify the diagnostic path. Therefore, through the construction of an algorithm from an evidence based approach, we believe we are providing some added improvements to facilitate and expedite the diagnosis of NPSLE.
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Affiliation(s)
| | - Chiara Giorgi
- b Radiology Department , S Maria della Misericordia Hospital , Urbino , Italy
| | - Domenico Maria Zardi
- c Division of Cardiology, Faculty of Medicine and Psychology , University of Rome "Sapienza", Sant'Andrea Hospital , Rome , Italy
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25
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Beishon L, Williams CAL, Robinson TG, Haunton VJ, Panerai RB. Neurovascular coupling response to cognitive examination in healthy controls: a multivariate analysis. Physiol Rep 2018; 6:e13803. [PMID: 30033685 PMCID: PMC6055030 DOI: 10.14814/phy2.13803] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 06/24/2018] [Indexed: 12/21/2022] Open
Abstract
Cognitive testing with transcranial Doppler ultrasonography (TCD) has been used to assess neurovascular coupling (NVC), but few studies address its multiple contributions. Subcomponent analysis considers the relative myogenic (resistance area product, RAP) and metabolic (critical closing pressure (CrCP)) contributors. The aim of this study was to investigate the changes in subcomponents that occur with cognitive stimulation with the Addenbrooke's Cognitive Examination (ACE-III) in healthy controls. Healthy volunteers underwent continuous recording of bilateral TCD, heart rate (HR, three-lead ECG), end-tidal CO2 (ETCO2 , capnography), and mean arterial pressure (MAP, Finometer). The study comprised a 5-min baseline recording, followed by all 20 paradigms from the ACE-III. The cerebral blood flow velocity (CBFv) response was decomposed into the relative contributions (subcomponents); VBP (MAP), VCrCP (CrCP), and VRAP (RAP). Data are presented as peak population normalized mean changes from baseline, and median area under the curve (AUC). Forty bilateral datasets were obtained (27 female, 37 right hand dominant). VBP increased at task initiation in all paradigms but differed between tasks (range (SD): 4.06 (8.92)-16.04 (12.23) %, P < 0.05). HR, but not ETCO2 , also differed significantly (P < 0.05). Changes in VRAP reflected changes in MAP, but in some paradigms atypical responses were seen. VCrCP AUC varied significantly within paradigm sections (range [SD]: 18.4 [24.17] to 244.21 [243.21] %*s, P < 0.05). All paradigms demonstrated changes in subcomponents with cognitive stimulation, and can be ranked based on their relative presumed metabolic demand. The integrity of NVC requires further investigation in patient populations.
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Affiliation(s)
- Lucy Beishon
- Department of Cardiovascular SciencesUniversity of LeicesterLeicesterUnited Kingdom
| | | | - Thompson G. Robinson
- Department of Cardiovascular SciencesUniversity of LeicesterLeicesterUnited Kingdom
- NIHR Leicester Biomedical Research CentreUniversity of LeicesterLeicesterUnited Kingdom
| | - Victoria J. Haunton
- Department of Cardiovascular SciencesUniversity of LeicesterLeicesterUnited Kingdom
- NIHR Leicester Biomedical Research CentreUniversity of LeicesterLeicesterUnited Kingdom
| | - Ronney B. Panerai
- Department of Cardiovascular SciencesUniversity of LeicesterLeicesterUnited Kingdom
- NIHR Leicester Biomedical Research CentreUniversity of LeicesterLeicesterUnited Kingdom
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26
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Payne SJ. Identifying the myogenic and metabolic components of cerebral autoregulation. Med Eng Phys 2018; 58:S1350-4533(18)30078-X. [PMID: 29773488 DOI: 10.1016/j.medengphy.2018.04.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 04/18/2018] [Accepted: 04/30/2018] [Indexed: 01/15/2023]
Abstract
Cerebral autoregulation is the term used to describe a number of mechanisms that act together to maintain a near constant cerebral blood flow in response to changes in arterial blood pressure. These mechanisms are complex and known to be affected in a range of cerebrovascular diseases. However, it can be difficult to assign an alteration in cerebral autoregulation to one of the underlying physiological mechanisms without the use of a complex mathematical model. In this paper, we thus set out a new approach that enables these mechanisms to be related to the autoregulation behaviour and hence inferred from experimental measurements. We show that the arteriolar response is a function of just three parameters, which we term the elastic, the myogenic and the metabolic sensitivity coefficients, and that the full vascular response is dependent upon only seven parameters. The ratio of the strengths of the myogenic and the metabolic responses is found to be in the range 2.5 to 5 over a wide range of pressure, indicating that the balance between the two appears to lie within this range. We validate the model with existing experimental data both at the level of an individual vessel and across the whole vasculature, and show that the results are consistent with findings from the literature. We then conduct a sensitivity analysis of the model to demonstrate which parameters are most important in determining the strength of static autoregulation, showing that autoregulation strength is predominantly set by the arteriolar sensitivity coefficients. This new approach could be used in future studies to help to interpret the components of the autoregulation response and how they are affected under different conditions, providing a greater insight into the fundamental processes that govern autoregulation.
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Affiliation(s)
- S J Payne
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, UK.
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27
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Caldas JR, Panerai RB, Salinet AM, Seng-Shu E, Ferreira GSR, Camara L, Passos RH, Galas FRBG, Almeida JP, Nogueira RC, de Lima Oliveira M, Robinson TG, Hajjar LA. Dynamic cerebral autoregulation is impaired during submaximal isometric handgrip in patients with heart failure. Am J Physiol Heart Circ Physiol 2018; 315:H254-H261. [PMID: 29652541 DOI: 10.1152/ajpheart.00727.2017] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The incidence of neurological complications, including stroke and cognitive dysfunction, is elevated in patients with heart failure (HF) with reduced ejection fraction. We hypothesized that the cerebrovascular response to isometric handgrip (iHG) is altered in patients with HF. Adults with HF and healthy volunteers were included. Cerebral blood velocity (CBV; transcranial Doppler, middle cerebral artery) and arterial blood pressure (BP; Finometer) were continuously recorded supine for 6 min, corresponding to 1 min of baseline and 3 min of iHG exercise, at 30% maximum voluntary contraction, followed by 2 min of recovery. The resistance-area product was calculated from the instantaneous BP-CBV relationship. Dynamic cerebral autoregulation (dCA) was assessed with the time-varying autoregulation index estimated from the CBV step response derived by an autoregressive moving-average time-domain model. Forty patients with HF and 23 BP-matched healthy volunteers were studied. Median left ventricular ejection fraction was 38.5% (interquartile range: 0.075%) in the HF group. Compared with control subjects, patients with HF exhibited lower time-varying autoregulation index during iHG, indicating impaired dCA ( P < 0.025). During iHG, there were steep rises in CBV, BP, and heart rate in control subjects but with different temporal patterns in HF, which, together with the temporal evolution of resistance-area product, confirmed the disturbance in dCA in HF. Patients with HF were more likely to have impaired dCA during iHG compared with age-matched control subjects. Our results also suggest an impairment of myogenic, neurogenic, and metabolic control mechanisms in HF. The relationship between impaired dCA and neurological complications in patients with HF during exercise deserves further investigation. NEW & NOTEWORTHY Our findings provide the first direct evidence that cerebral blood flow regulatory mechanisms can be affected in patients with heart failure during isometric handgrip exercise. As a consequence, eventual blood pressure modulations are buffered less efficiently and metabolic demands may not be met during common daily activities. These deficits in cerebral autoregulation are compounded by limitations of the systemic response to isometric exercise, suggesting that patients with heart failure may be at greater risk for cerebral events during exercise.
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Affiliation(s)
- J R Caldas
- Department of Anesthesia, Heart Institute, University of Sao Paulo , Sao Paulo , Brazil.,Department of Neurosurgery, Hospital das Clinicas, University of São Paulo , São Paulo , Brazil.,Critical Care Unit, Hospital São Rafael , Salvador , Brazil
| | - R B Panerai
- Department of Cardiovascular Sciences, University of Leicester , Leicester , United Kingdom.,NIHR Leicester Biomedical Research Centre, Glenfield Hospital , Leicester , United Kingdom
| | | | - E Seng-Shu
- Department of Neurosurgery, Hospital das Clinicas, University of São Paulo , São Paulo , Brazil
| | - G S R Ferreira
- Department of Anesthesia, Heart Institute, University of Sao Paulo , Sao Paulo , Brazil
| | - L Camara
- Department of Anesthesia, Heart Institute, University of Sao Paulo , Sao Paulo , Brazil
| | - R H Passos
- Critical Care Unit, Hospital São Rafael , Salvador , Brazil
| | - F R B G Galas
- Department of Anesthesia, Heart Institute, University of Sao Paulo , Sao Paulo , Brazil
| | | | - R C Nogueira
- Department of Neurosurgery, Hospital das Clinicas, University of São Paulo , São Paulo , Brazil
| | - M de Lima Oliveira
- Department of Neurosurgery, Hospital das Clinicas, University of São Paulo , São Paulo , Brazil
| | - T G Robinson
- Department of Cardiovascular Sciences, University of Leicester , Leicester , United Kingdom.,NIHR Leicester Biomedical Research Centre, Glenfield Hospital , Leicester , United Kingdom
| | - L A Hajjar
- Department of Cardiopneumology, Heart Institute, University of Sao Paulo , São Paulo , Brazil
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28
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Beishon LC, Williams CAL, Panerai RB, Robinson TG, Haunton VJ. The assessment of neurovascular coupling with the Addenbrooke’s Cognitive Examination: a functional transcranial Doppler ultrasonographic study. J Neurophysiol 2018; 119:1084-1094. [DOI: 10.1152/jn.00698.2017] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Cerebrovascular dysfunction occurs early in dementia and can be identified by transcranial Doppler ultrasonography (TCD). Few studies have examined cerebral blood flow velocity (CBFv) responses to a detailed cognitive battery. This study aimed to characterize all CBFv responses, and the effect of hemispheric dominance, to the Addenbrooke’s Cognitive Examination (ACE-III) in healthy volunteers. Forty volunteers underwent continuous bilateral TCD, beat-to-beat blood pressure (MAP; Finapres), heart rate (HR; electrocardiogram), and end-tidal CO2 (ETCO2; capnography) monitoring. After a 5-min baseline period, all tasks from the ACE-III were performed in 3 sections (A: attention, fluency, memory; B: language; C: visuospatial, memory). Data are population mean normalized percentage (PM%) change from a 20-s baseline period before task initiation. Forty bilateral data sets were obtained (27 women, 37 right-hand dominant). All paradigms produced a sharp increase in CBFv in both dominant (PM% range: 3.29 to 9.70%) and nondominant (PM% range: 4.34 to 11.63%) hemispheres at task initiation, with associated increases in MAP (PM% range: 3.06 to 16.04%). ETCO2 did not differ significantly at task initiation (PM% range: −1.1 to 2.4%, P > 0.05). HR differed significantly across A and C tasks at initiation (PM% range: −1.1 to 2.4%, P < 0.05), but not B tasks. In conclusion, all tasks resulted in increases in CBFv, differing significantly between paradigms. These results require further investigation in a cognitively impaired population. NEW & NOTEWORTHY This study is the first to provide a normative data set of cerebral blood flow velocity (CBFv) responses to a complete cognitive assessment (Addenbrooke’s Cognitive Examination, ACE-III) in a large sample ( n = 40) of healthy volunteers. All tasks produced peak and sustained increases in CBFv to different extents. The ACE-III is a feasible tool to assess neurovascular coupling with transcranial Doppler ultrasonography. These data can be used to inform the most appropriate cognitive task to elicit CBFv responses for future studies.
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Affiliation(s)
- Lucy C. Beishon
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
| | - Claire A. L. Williams
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
| | - Ronney B. Panerai
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- NIHR Leicester Biomedical Research Centre, University of Leicester, Leicester, United Kingdom
| | - Thompson G. Robinson
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- NIHR Leicester Biomedical Research Centre, University of Leicester, Leicester, United Kingdom
| | - Victoria J. Haunton
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- NIHR Leicester Biomedical Research Centre, University of Leicester, Leicester, United Kingdom
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29
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Lam MY, Haunton VJ, Robinson TG, Panerai RB. Does gradual change in head positioning affect cerebrovascular physiology? Physiol Rep 2018; 6:e13603. [PMID: 29417750 PMCID: PMC5803526 DOI: 10.14814/phy2.13603] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 12/29/2017] [Indexed: 11/24/2022] Open
Abstract
We studied cerebral blood velocity (CBV), and associated hemodynamic parameters during gradual changes in head positioning in a nonstroke group. CBV (transcranial Doppler ultrasound), beat-to-beat blood pressure (BP, Finometer), and end-tidal carbon dioxide (ETCO2 , capnography) were recorded between lying flat (0°) and sitting up (30°) head positions, in 18 volunteers (10 female, mean age, 57 ± 16 years), at two visits (12 ± 8 days). A significant reduction was found between 5-min FLAT (0°) and 5-min SIT (30°) positions in CBV (visit 1: 4.5 ± 3.3%, P = 0.006; visit 2: 4.1 ± 3.5%, P = 0.003), critical closing pressure (CrCP; visit 1: 15.5 ± 14.0%, P = 0.0002; visit 2: 14.1 ± 7.8%, P = 0.009) and BP (visit 1: 8.3 ± 7.4%, P = 0.001; visit 2: 11.0 ± 11.3%, P < 0.001). For 5 min segments of data, the autoregulation index and other hemodynamic parameters did not show differences either due to head position or visit. For 30 sec time intervals, significant differences were observed in the following: (BP, P < 0.001; dominant hemisphere (DH) CBV, P < 0.005; nondominant hemisphere (NDH) CBV, P < 0.005; DH CrCP, P < 0.001; NDH CrCP, P < 0.001; DH resistance area product (RAP), P = 0.002; NDH RAP, P = 0.033). Significant static changes in BP, CBV and CrCP, and large transient changes in key hemodynamic parameters occur during 0° to 30°, and vice versa, with reproducible results. Further studies are needed following acute ischemic stroke to determine if a similar responses is present.
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Affiliation(s)
- Man Y. Lam
- Department of Cardiovascular SciencesUniversity of LeicesterLeicesterUnited Kingdom
| | - Victoria J. Haunton
- Department of Cardiovascular SciencesUniversity of LeicesterLeicesterUnited Kingdom
- National Institute for Health Research Leicester Biomedical Research CentreUniversity of LeicesterLeicesterUnited Kingdom
| | - Thompson G. Robinson
- Department of Cardiovascular SciencesUniversity of LeicesterLeicesterUnited Kingdom
- National Institute for Health Research Leicester Biomedical Research CentreUniversity of LeicesterLeicesterUnited Kingdom
| | - Ronney B. Panerai
- Department of Cardiovascular SciencesUniversity of LeicesterLeicesterUnited Kingdom
- National Institute for Health Research Leicester Biomedical Research CentreUniversity of LeicesterLeicesterUnited Kingdom
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30
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Abstract
Sex and gender, as biological and social factors, significantly influence health outcomes. Among the biological factors, sex differences in vascular physiology may be one specific mechanism contributing to the observed differences in clinical presentation, response to treatment, and clinical outcomes in several vascular disorders. This review focuses on the cerebrovascular bed and summarizes the existing literature on sex differences in cerebrovascular hemodynamics to highlight the knowledge deficit that exists in this domain. The available evidence is used to generate mechanistically plausible and testable hypotheses to underscore the unmet need in understanding sex-specific mechanisms as targets for more effective therapeutic and preventive strategies.
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Affiliation(s)
- Cristina Duque
- Division of Stroke and Neurocritical Care, Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois.,Department of Neurology, Coimbra University Hospital Center, Coimbra, Portugal
| | - Steven K Feske
- Division of Stroke, Department of Neurology, Brigham and Women's Hospital, Boston, Massachusetts
| | - Farzaneh A Sorond
- Division of Stroke and Neurocritical Care, Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
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31
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Barnes SC, Ball N, Haunton VJ, Robinson TG, Panerai RB. The cerebrocardiovascular response to periodic squat-stand maneuvers in healthy subjects: a time-domain analysis. Am J Physiol Heart Circ Physiol 2017; 313:H1240-H1248. [DOI: 10.1152/ajpheart.00331.2017] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Squat-stand maneuvers (SSMs) have been used to improve the coherence of transfer function analysis (TFA) estimates during the assessment of dynamic cerebral autoregulation (dCA). There is a need to understand the influence of peripheral changes resulting from SSMs on cerebral blood flow, which might confound estimates of dCA. Healthy subjects ( n = 29) underwent recordings at rest (5-min standing) and 15 SSMs (0.05 Hz). Heart rate (three-lead ECG), end-tidal CO2 (capnography), blood pressure (Finometer), cerebral blood velocity (CBV; transcranial Doppler, middle cerebral artery), and the angle of the thigh (tilt sensor) were measured continuously. The response of CBV to SSMs was decomposed into the relative contributions of mean arterial pressure (MAP), resistance-area product (RAP), and critical closing pressure (CrCP). Upon squatting, a rise in MAP (83.6 ± 21.1% contribution) was followed by increased CBV. A dCA response could be detected, determined by adjustments in RAP and CrCP (left hemisphere) with peak contributions of 24.8 ± 12.7% and 27.4 ± 22.8%, respectively, at different times during SSMs. No interhemispheric differences were detected. During standing, the contributions of MAP, RAP, and CrCP changed considerably. In conclusion, the changes of CBV subcomponents during repeated SSMs indicate a complex response of CBV to SSMs that can only be partially explained by myogenic mechanisms. More work is needed to clarify the potential contribution of other cofactors, such as breath-to-breath changes in Pco2, heart rate, stroke volume, and the neurogenic component of dCA. NEW & NOTEWORTHY Here, we describe the different contributions to the cerebral blood flow response after squat-stand maneuvers. Furthermore, we demonstrate the complex interaction of peripheral and cerebral parameters for the first time. Moreover, we show that the cerebral blood velocity response to squatting is likely to include a significant metabolic component.
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Affiliation(s)
- Sam C. Barnes
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
| | - Naomi Ball
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
| | - Victoria Joanna Haunton
- National Institute for Health Research, Leicester Biomedical Research Centre, University of Leicester, Leicester, United Kingdom
| | - Thompson G. Robinson
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- National Institute for Health Research, Leicester Biomedical Research Centre, University of Leicester, Leicester, United Kingdom
| | - Ronney B. Panerai
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- National Institute for Health Research, Leicester Biomedical Research Centre, University of Leicester, Leicester, United Kingdom
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32
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Castro P, Freitas J, Santos R, Panerai R, Azevedo E. Indexes of cerebral autoregulation do not reflect impairment in syncope: insights from head-up tilt test of vasovagal and autonomic failure subjects. Eur J Appl Physiol 2017; 117:1817-1831. [PMID: 28681121 DOI: 10.1007/s00421-017-3674-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 06/26/2017] [Indexed: 12/27/2022]
Abstract
PURPOSE The study of dynamic cerebral autoregulation (CA), which adapts cerebral blood flow to arterial blood pressure (ABP) fluctuations, has been limited in orthostatic intolerance syndromes, mainly due to its stationary prerequisites hardly to meet during maneuvers to provoke syncope itself. New techniques of continuous estimates of CA could overcome this pitfall. We aimed to evaluate CA during head-up tilt test in common conditions causing syncope. METHODS We compared three groups: eight controls; eight patients with autonomic failure due to familial amyloidotic polyneuropathy; eight patients with vasovagal syncope (VVS). ABP and cerebral blood flow velocity (CBFV) were measured with Finometer® and transcranial Doppler. We calculated cerebrovascular resistance index (CVRi), critical closing pressure (CrCP) and resistance area product (RAP), and derived CA continuously from autoregulation index [ARI(t)]. RESULTS With HUTT, AF subjects showed a pronounced decrease in CBFV (-36 ± 17 versus -7 ± 6%, p < 0.0001), ABP (-29 ± 27 versus 7 ± 12%, p < 0.0001) and RAP (-17 ± 23 versus 3 ± 18%, p < 0.0001) but not CVRi (p = 0.110). VVS subjects showed progressive cerebral vasoconstriction prior to syncope, (reduced CBFV 19 ± 15 versus 1 ± 6, p < 0.000; increased RAP 12 ± 18 versus 2 ± 3%, p = 0.024 and CVRi 12 ± 18 versus 2 ± 3%, p = 0.005). ARI(t) increased significantly in AF patients (5.7 ± 1.2 versus 6.9 ± 1.2, p = 0.040) and VVS (5.8 ± 1.2 versus 7.3 ± 1.2, p = 0.015) in response to ABP fall during syncope. CONCLUSIONS Our data suggest that dynamic cerebral autoregulatory response to orthostatic challenge is neither affected by autonomic dysfunction nor in neutrally mediated syncope. This study also emphasizes that RAP + CrCP model is more informative than CVRi, mainly during cerebral vasodilatory response to orthostatic hypotension.
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Affiliation(s)
- Pedro Castro
- Department of Neurology, São João Hospital Center, Faculty of Medicine of University of Porto, Alameda Professor Hernani Monteiro, 4200-319, Porto, Portugal.
| | - João Freitas
- Autonomic Unit, São João Hospital Center, Faculty of Medicine of University of Porto, Porto, Portugal
| | - Rosa Santos
- Department of Neurology, São João Hospital Center, Faculty of Medicine of University of Porto, Alameda Professor Hernani Monteiro, 4200-319, Porto, Portugal
| | - Ronney Panerai
- Department of Cardiovascular Sciences and NIH Biomedical Research Centre, University of Leicester, Leicester, UK
| | - Elsa Azevedo
- Department of Neurology, São João Hospital Center, Faculty of Medicine of University of Porto, Alameda Professor Hernani Monteiro, 4200-319, Porto, Portugal
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Malojcic B, Giannakopoulos P, Sorond FA, Azevedo E, Diomedi M, Oblak JP, Carraro N, Boban M, Olah L, Schreiber SJ, Pavlovic A, Garami Z, Bornstein NM, Rosengarten B. Ultrasound and dynamic functional imaging in vascular cognitive impairment and Alzheimer's disease. BMC Med 2017; 15:27. [PMID: 28178960 PMCID: PMC5299782 DOI: 10.1186/s12916-017-0799-3] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 01/21/2017] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND The vascular contributions to neurodegeneration and neuroinflammation may be assessed by magnetic resonance imaging (MRI) and ultrasonography (US). This review summarises the methodology for these widely available, safe and relatively low cost tools and analyses recent work highlighting their potential utility as biomarkers for differentiating subtypes of cognitive impairment and dementia, tracking disease progression and evaluating response to treatment in various neurocognitive disorders. METHODS At the 9th International Congress on Vascular Dementia (Ljubljana, Slovenia, October 2015) a writing group of experts was formed to review the evidence on the utility of US and arterial spin labelling (ASL) as neurophysiological markers of normal ageing, vascular cognitive impairment (VCI) and Alzheimer's disease (AD). Original articles, systematic literature reviews, guidelines and expert opinions published until September 2016 were critically analysed to summarise existing evidence, indicate gaps in current knowledge and, when appropriate, suggest standards of use for the most widely used US and ASL applications. RESULTS Cerebral hypoperfusion has been linked to cognitive decline either as a risk or an aggravating factor. Hypoperfusion as a consequence of microangiopathy, macroangiopathy or cardiac dysfunction can promote or accelerate neurodegeneration, blood-brain barrier disruption and neuroinflammation. US can evaluate the cerebrovascular tree for pathological structure and functional changes contributing to cerebral hypoperfusion. Microvascular pathology and hypoperfusion at the level of capillaries and small arterioles can also be assessed by ASL, an MRI signal. Despite increasing evidence supporting the utility of these methods in detection of microvascular pathology, cerebral hypoperfusion, neurovascular unit dysfunction and, most importantly, disease progression, incomplete standardisation and missing validated cut-off values limit their use in daily routine. CONCLUSIONS US and ASL are promising tools with excellent temporal resolution, which will have a significant impact on our understanding of the vascular contributions to VCI and AD and may also be relevant for assessing future prevention and therapeutic strategies for these conditions. Our work provides recommendations regarding the use of non-invasive imaging techniques to investigate the functional consequences of vascular burden in dementia.
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Affiliation(s)
- Branko Malojcic
- Department of Neurology, University Hospital Center Zagreb, Zagreb School of Medicine, Kispaticeva 12, 10000, Zagreb, Croatia.
| | | | - Farzaneh A Sorond
- Department of Neurology, Northwestern University Feinberg School of Medicine Chicago, Chicago, IL, USA
| | - Elsa Azevedo
- Department of Neurology, São João Hospital Center and Faculty of Medicine of University of Porto, Porto, Portugal
| | - Marina Diomedi
- Cerebrovascular Disease Center, Stroke Unit, University of Rome Tor Vergata, Rome, Italy
| | - Janja Pretnar Oblak
- Department of Vascular Neurology and Intensive Therapy, University Medical Center Ljubljana, Ljubljana, Slovenia
| | - Nicola Carraro
- Department of Medical Sciences, Clinical Neurology-Stroke Unit, University Hospital, University of Trieste, Trieste, Italy
| | - Marina Boban
- Department of Neurology, University Hospital Center Zagreb, Zagreb School of Medicine, Kispaticeva 12, 10000, Zagreb, Croatia
| | - Laszlo Olah
- Department of Neurology, University of Debrecen, Debrecen, Hungary
| | - Stephan J Schreiber
- Department of Neurology, Charite - Universitätsmedizin Berlin, Berlin, Germany
| | - Aleksandra Pavlovic
- Neurology Clinic, Clinical Center of Serbia, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Zsolt Garami
- Methodist DeBakey Heart and Vascular Center, Houston, TX, USA
| | - Nantan M Bornstein
- Neurology Department, Tel Aviv Sourasky Medical Centre, Tel Aviv, Israel
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Schuepbach D, Egger ST, Boeker H, Duschek S, Vetter S, Seifritz E, Herpertz SC. Determinants of cerebral hemodynamics during the Trail Making Test in schizophrenia. Brain Cogn 2016; 109:96-104. [PMID: 27648976 DOI: 10.1016/j.bandc.2016.09.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 09/08/2016] [Accepted: 09/08/2016] [Indexed: 10/21/2022]
Abstract
Patients with schizophrenia show deficits in cognitive functioning, and studies on cerebral hemodynamics have revealed aberrant patterns of mean cerebral blood flow velocity (MFV), an equivalent of cerebral blood flow (CBF). Therefore, we carried out a controlled study that assessed MFV in schizophrenia during a well-known neuropsychological task, the Trail Making Test (TMT). We measured MFV in the middle cerebral arteries using functional transcranial Doppler sonography in 15 schizophrenia patients and 15 healthy subjects. In comparison to healthy subjects, patients performed poorer on the TMT-A and the TMT-B, and there was increased cerebral blood flow velocity during the TMT-B. A comparison of subgroups of patients and controls matched in performance on the TMT-B revealed that these patients still showed significantly increased cerebral blood flow velocity. Increased MFV in schizophrenia suggests specific alterations of cerebral hemodynamics during the Trail Making Test, Part B, which are not detectable during visuomotor activity, and which are independent of performance. These findings emphasize the pathophysiological importance of cognitive functioning in schizophrenia, but cast doubts whether performance in this particular test plays a relevant role for CBF abnormalities in schizophrenia.
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Affiliation(s)
- Daniel Schuepbach
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric University Hospital Zurich, Zurich, Switzerland; Department of General Psychiatry, Center of Psychosocial Medicine, University of Heidelberg, Heidelberg, Germany; Klinikum am Weissenhof, Weinsberg, Germany.
| | - Stephan T Egger
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric University Hospital Zurich, Zurich, Switzerland
| | - Heinz Boeker
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric University Hospital Zurich, Zurich, Switzerland
| | - Stefan Duschek
- Institute of Psychology, UMIT - University for Health Sciences, Medical Informatics and Technology, Hall in Tirol, Austria
| | - Stefan Vetter
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric University Hospital Zurich, Zurich, Switzerland
| | - Erich Seifritz
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric University Hospital Zurich, Zurich, Switzerland
| | - Sabine C Herpertz
- Department of General Psychiatry, Center of Psychosocial Medicine, University of Heidelberg, Heidelberg, Germany
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Shin KJ, Kim SE, Park KM, Park J, Ha SY, Kim SE, Kwon OY. Cerebral hemodynamics in orthostatic intolerance with normal head-up tilt test. Acta Neurol Scand 2016; 134:108-15. [PMID: 26427910 DOI: 10.1111/ane.12516] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/11/2015] [Indexed: 11/30/2022]
Abstract
OBJECTIVES Orthostatic hypotension (OH) and postural orthostatic tachycardia syndrome (POTS) are well-known causes of orthostatic intolerance (OI). In addition, there are OI patients who are characterized by the symptoms of OI and lack of abnormal findings in head-up tilt (HUT) test. The aim of this study was to determine the cerebral hemodynamic changes in HUT test of OI patients with normal HUT (OINH). MATERIALS AND METHODS Two hundred and sixty-one OI patients and 50 healthy controls were enrolled in this study. All subjects underwent transcranial Doppler test while performing the HUT test. Forty-five patients had OH, 33 patients had POTS, and 183 patients had OINH. Blood pressures, heart rate, cerebral blood flow velocities (CBFVs), end-tidal carbon dioxide (ET-PCO2 ), cerebral critical closing pressure (CCP), cerebral perfusion pressure (CPP), and cerebral vascular resistance (CVR) were measured during HUT test. We compared the hemodynamic parameters of OINH with those of OH, POTS, and healthy controls. RESULTS Reduced CBFVs, CPP, and ET-PCO2 and elevated CCP were observed in the HUT test of all four groups. CVR was reduced in three OI patients. The drops in systolic CBFV, CPP, and CVR of OINH patients were greater than those of healthy controls. The changes in parameters in the HUT test of OINH group were not different from those of OH and POTS groups except prominent decrements of CPP and CVR in OH group. CONCLUSION Our findings suggest that OINH is true OI sharing the common pathomechanism of OH and POTS.
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Affiliation(s)
- K. J. Shin
- Department of Neurology; Haeundae Paik Hospital; Inje University; Busan South Korea
| | - S. E. Kim
- Department of Neurology; Haeundae Paik Hospital; Inje University; Busan South Korea
| | - K. M. Park
- Department of Neurology; Haeundae Paik Hospital; Inje University; Busan South Korea
| | - J. Park
- Department of Neurology; Haeundae Paik Hospital; Inje University; Busan South Korea
| | - S. Y. Ha
- Department of Neurology; Haeundae Paik Hospital; Inje University; Busan South Korea
| | - S. E. Kim
- Department of Neurology; Haeundae Paik Hospital; Inje University; Busan South Korea
| | - O.-Y. Kwon
- Department of Neurology; School of Medicine; Gyeongsang National University; Jinju South Korea
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Katsogridakis E, Simpson DM, Bush G, Fan L, Birch AA, Allen R, Potter JF, Panerai RB. Revisiting the frequency domain: the multiple and partial coherence of cerebral blood flow velocity in the assessment of dynamic cerebral autoregulation. Physiol Meas 2016; 37:1056-73. [DOI: 10.1088/0967-3334/37/7/1056] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Carbon dioxide induced changes in cerebral blood flow and flow velocity: role of cerebrovascular resistance and effective cerebral perfusion pressure. J Cereb Blood Flow Metab 2015; 35:1470-7. [PMID: 25873428 PMCID: PMC4640336 DOI: 10.1038/jcbfm.2015.63] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 02/17/2015] [Accepted: 03/12/2015] [Indexed: 11/08/2022]
Abstract
In addition to cerebrovascular resistance (CVR) zero flow pressure (ZFP), effective cerebral perfusion pressure (CPPe) and the resistance area product (RAP) are supplemental determinants of cerebral blood flow (CBF). Until now, the interrelationship of PaCO2-induced changes in CBF, CVR, CPPe, ZFP, and RAP is not fully understood. In a controlled crossover trial, we investigated 10 anesthetized patients aiming at PaCO2 levels of 30, 37, 43, and 50 mm Hg. Cerebral blood flow was measured with a modified Kety-Schmidt-technique. Zero flow pressure and RAP was estimated by linear regression analysis of pressure-flow velocity relationships of the middle cerebral artery. Effective cerebral perfusion pressure was calculated as the difference between mean arterial pressure and ZFP, CVR as the ratio CPPe/CBF. Statistical analysis was performed by one-way RM-ANOVA. When comparing hypocapnia with hypercapnia, CBF showed a significant exponential reduction by 55% and mean VMCA by 41%. Effective cerebral perfusion pressure linearly decreased by 17% while ZFP increased from 14 to 29 mm Hg. Cerebrovascular resistance increased by 96% and RAP by 39%; despite these concordant changes in mean CVR and Doppler-derived RAP correlation between these variables was weak (r=0.43). In conclusion, under general anesthesia hypocapnia-induced reduction in CBF is caused by both an increase in CVR and a decrease in CPPe, as a consequence of an increase in ZFP.
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Panerai RB, Saeed NP, Robinson TG. Cerebrovascular effects of the thigh cuff maneuver. Am J Physiol Heart Circ Physiol 2015; 308:H688-96. [PMID: 25659488 PMCID: PMC4385993 DOI: 10.1152/ajpheart.00887.2014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 02/05/2015] [Indexed: 11/22/2022]
Abstract
Arterial hypotension can be induced by sudden release of inflated thigh cuffs (THC), but its effects on the cerebral circulation have not been fully described. In nine healthy subjects [aged 59 (9) yr], bilateral cerebral blood flow velocity (CBFV) was recorded in the middle cerebral artery (MCA), noninvasive arterial blood pressure (BP) in the finger, and end-tidal CO2 (ETCO2) with nasal capnography. Three THC maneuvers were performed in each subject with cuff inflation 20 mmHg above systolic BP for 3 min before release. Beat-to-beat values were extracted for mean CBFV, BP, ETCO2 , critical closing pressure (CrCP), resistance-area product (RAP), and heart rate (HR). Time-varying estimates of the autoregulation index [ARI(t)] were also obtained using an autoregressive-moving average model. Coherent averages synchronized by the instant of cuff release showed significant drops in mean BP, CBFV, and RAP with rapid return of CBFV to baseline. HR, ETCO2 , and ARI(t) were transiently increased, but CrCP remained relatively constant. Mean values of ARI(t) for the 30 s following cuff release were not significantly different from the classical ARI [right MCA 5.9 (1.1) vs. 5.1 (1.6); left MCA 5.5 (1.4) vs. 4.9 (1.7)]. HR was strongly correlated with the ARI(t) peak after THC release (in 17/22 and 21/24 recordings), and ETCO2 was correlated with the subsequent drop in ARI(t) (19/22 and 20/24 recordings). These results suggest a complex cerebral autoregulatory response to the THC maneuver, dominated by myogenic mechanisms and influenced by concurrent changes in ETCO2 and possible involvement of the autonomic nervous system and baroreflex.
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Affiliation(s)
- R B Panerai
- University of Leicester, Department of Cardiovascular Sciences, Leicester Royal Infirmary, Leicester, United Kingdom; and National Institutes for Health Research, Biomedical Research Unit in Cardiovascular Science, Glenfield Hospital, Leicester, United Kingdom
| | - N P Saeed
- University of Leicester, Department of Cardiovascular Sciences, Leicester Royal Infirmary, Leicester, United Kingdom; and
| | - T G Robinson
- University of Leicester, Department of Cardiovascular Sciences, Leicester Royal Infirmary, Leicester, United Kingdom; and National Institutes for Health Research, Biomedical Research Unit in Cardiovascular Science, Glenfield Hospital, Leicester, United Kingdom
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van Veen TR, Panerai RB, Haeri S, Zeeman GG, Belfort MA. Effect of breath holding on cerebrovascular hemodynamics in normal pregnancy and preeclampsia. J Appl Physiol (1985) 2015; 118:858-62. [PMID: 25614597 DOI: 10.1152/japplphysiol.00562.2014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 01/20/2015] [Indexed: 11/22/2022] Open
Abstract
Preeclampsia (PE) is associated with endothelial dysfunction and impaired autonomic function, which is hypothesized to cause cerebral hemodynamic abnormalities. Our aim was to test this hypothesis by estimating the difference in the cerebrovascular response to breath holding (BH; known to cause sympathetic stimulation) between women with preeclampsia and a group of normotensive controls. In a prospective cohort analysis, cerebral blood flow velocity (CBFV) in the middle cerebral artery (transcranial Doppler), blood pressure (BP, noninvasive arterial volume clamping), and end-tidal carbon dioxide (EtCO2) were simultaneously recorded during a 20-s breath hold maneuver. CBFV changes were broken down into standardized subcomponents describing the relative contributions of BP, cerebrovascular resistance index (CVRi), critical closing pressure (CrCP), and resistance area product (RAP). The area under the curve (AUC) was calculated for changes in relation to baseline values. A total of 25 preeclamptic (before treatment) and 25 normotensive women in the second half of pregnancy were enrolled, and, 21 patients in each group were included in the analysis. The increase in CBFV and EtCO2 was similar in both groups. However, the AUC for CVRi and RAP during BH was significantly different between the groups (3.05 ± 2.97 vs. -0.82 ± 4.98, P = 0.006 and 2.01 ± 4.49 vs. -2.02 ± 7.20, P = 0.037), indicating an early, transient increase in CVRi and RAP in the control group, which was absent in PE. BP had an equal contribution in both groups. Women with preeclampsia have an altered initial CVRi response to the BH maneuver. We propose that this is due to blunted sympathetic or myogenic cerebrovascular response in women with preeclampsia.
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Affiliation(s)
- Teelkien R van Veen
- University of Groningen, University Medical Center Groningen, Department of Obstetrics and Gynecology, Groningen, the Netherlands; Baylor College of Medicine, Department of Obstetrics and Gynecology, Houston, Texas;
| | - Ronney B Panerai
- University of Leicester, Department of Cardiovascular Sciences, Leicester, United Kingdom; and
| | - Sina Haeri
- Baylor College of Medicine, Department of Obstetrics and Gynecology, Houston, Texas; St. David's Women's Center of Texas, North Austin Maternal-Fetal Medicine, Austin, Texas
| | - Gerda G Zeeman
- University of Groningen, University Medical Center Groningen, Department of Obstetrics and Gynecology, Groningen, the Netherlands
| | - Michael A Belfort
- Baylor College of Medicine, Department of Obstetrics and Gynecology, Houston, Texas
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Salinet ASM, Robinson TG, Panerai RB. Effects of cerebral ischemia on human neurovascular coupling, CO2 reactivity, and dynamic cerebral autoregulation. J Appl Physiol (1985) 2014; 118:170-7. [PMID: 25593216 DOI: 10.1152/japplphysiol.00620.2014] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Cerebral blood flow (CBF) regulation can be impaired in acute ischemic stroke but the combined effects of dynamic cerebral autoregulation (CA), CO2 cerebrovascular reactivity (CVR), and neurovascular coupling (NVC), obtained from simultaneous measurements, have not been described. CBF velocity in the middle cerebral artery (MCA) (CBFv, transcranial Doppler), blood pressure (BP, Finometer), and end-tidal Pco2 (PetCO2 , infrared capnography) were recorded during a 1-min passive movement of the arm in 27 healthy controls [mean age (SD) 61.4 (6.0) yr] and 27 acute stroke patients [age 63 (11.7) yr]. A multivariate autoregressive-moving average model was used to separate the contributions of BP, arterial Pco2 (PaCO2 ), and the neural activation to the CBFv responses. CBFv step responses for the BP, CO2, and stimulus inputs were also obtained. The contribution of the stimulus to the CBFv response was highly significant for the difference between the affected side [area under the curve (AUC) 104.5 (4.5)%] and controls [AUC 106.9 (4.3)%; P = 0.008]. CBFv step responses to CO2 [affected hemisphere 0.39 (0.7), unaffected 0.55 (0.8), controls 1.39 (0.9)%/mmHg; P = 0.01, affected vs. controls; P = 0.025, unaffected vs. controls] and motor stimulus inputs [affected hemisphere 0.20 (0.1), unaffected 0.22 (0.2), controls 0.37 (0.2) arbitrary units; P = 0.009, affected vs. controls; P = 0.02, unaffected vs. controls] were reduced in the stroke group compared with controls. The CBFv step responses to the BP input at baseline and during the paradigm were not different between groups (P = 0.07), but PetCO2 was lower in the stroke group (P < 0.05). These results provide new insights into the interaction of CA, CVR, and NVC in both health and disease states.
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Affiliation(s)
- Angela S M Salinet
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom; and
| | - Thompson G Robinson
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom; and National Institutes for Health Research (NIHR), Biomedical Research Unit in Cardiovascular Sciences, Glenfield Hospital, Leicester, United Kingdom
| | - Ronney B Panerai
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom; and National Institutes for Health Research (NIHR), Biomedical Research Unit in Cardiovascular Sciences, Glenfield Hospital, Leicester, United Kingdom
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Salinet ASM, Panerai RB, Robinson TG. The longitudinal evolution of cerebral blood flow regulation after acute ischaemic stroke. Cerebrovasc Dis Extra 2014; 4:186-97. [PMID: 25298773 PMCID: PMC4176407 DOI: 10.1159/000366017] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 07/20/2014] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Acute stroke is known to impair cerebral blood flow (CBF) regulation, but the longitudinal changes of these effects have been poorly reported. The main CBF regulatory mechanisms [cerebral autoregulation (CA) and neurovascular coupling (NVC)] were assessed over 3 months after acute ischaemic stroke. METHODS Recordings of CBF velocity (CBFv), blood pressure (BP), and end-tidal CO2 were performed during 5 min baseline and 1 min passive movement of the elbow. Stroke patients were assessed <72 h of stroke onset, and at 2 weeks, 1 and 3 months after stroke. RESULTS Fifteen acute stroke subjects underwent all 4 sessions and were compared to 22 control subjects. Baseline recordings revealed a significantly lower CBFv in the affected hemisphere within 72 h after stroke compared to controls (p = 0.02) and a reduction in CA index most marked at 2 weeks (p = 0.009). CBFv rise in response to passive arm movement was decreased bilaterally after stroke, particularly in the affected hemisphere (p < 0.01). Both alterations in CA and NVC returned to control levels during recovery. CONCLUSION The major novel finding of this study was that both CA and NVC regulatory mechanisms deteriorated initially following stroke onset, but returned to control levels during the recovery period. These findings are relevant to guide the timing of interventions to manipulate BP and potentially for the impact of intensive rehabilitation strategies that may precipitate acute physiological perturbations but require further exploration in a larger population that better reflects the heterogeneity of stroke. Further, they will also enable the potential influence of stroke subtype to be investigated.
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Affiliation(s)
- Angela S M Salinet
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
| | - Ronney B Panerai
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK ; National Institutes for Health Research, Biomedical Research Unit in Cardiovascular Sciences, Clinical Sciences Wing, Glenfield Hospital, Leicester, UK
| | - Thompson G Robinson
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK ; National Institutes for Health Research, Biomedical Research Unit in Cardiovascular Sciences, Clinical Sciences Wing, Glenfield Hospital, Leicester, UK
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Castro PM, Santos R, Freitas J, Panerai RB, Azevedo E. Autonomic dysfunction affects dynamic cerebral autoregulation during Valsalva maneuver: comparison between healthy and autonomic dysfunction subjects. J Appl Physiol (1985) 2014; 117:205-13. [PMID: 24925980 DOI: 10.1152/japplphysiol.00893.2013] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The role of autonomic nervous system (ANS) in adapting cerebral blood flow (CBF) to arterial blood pressure (ABP) fluctuations [cerebral autoregulation (CA)] is still controversial. We aimed to study the repercussion of autonomic failure (AF) on dynamic CA during the Valsalva maneuver (VM). Eight AF subjects with familial amyloidotic polineuropahty (FAP) were compared with eight healthy controls. ABP and CBF velocity (CBFV) were measured continuously with Finapres and transcranial Doppler, respectively. Cerebrovascular response was evaluated by cerebrovascular resistance index (CVRi), critical closing pressure (CrCP), and resistance-area product (RAP) changes. Dynamic CA was derived from continuous estimates of autoregulatory index (ARI) [ARI(t)]. During phase II of VM, FAP subjects showed a more pronounced decrease in normalized CBFV (78 ± 19 and 111 ± 16%; P = 0.002), ABP (78 ± 19 and 124 ± 12%; P = 0.0003), and RAP (67 ± 17 and 89 ± 17%; P = 0.019) compared with controls. CrCP and CVRi increased similarly in both groups during strain. ARI(t) showed a biphasic variation in controls with initial increase followed by a decrease during phase II but in FAP this response was blunted (5.4 ± 3.0 and 2.0 ± 2.9; P = 0.033). Our data suggest that dynamic cerebral autoregulatory response is a time-varying phenomena during VM and that it is disturbed by autonomic dysfunction. This study also emphasizes the fact that RAP + CrCP model allowed additional insights into understanding of cerebral hemodynamics, showing a higher vasodilatory response expressed by RAP in AF and an equal CrCP response in both groups during the increased intracranial and intrathoracic pressure, while classical CVRi paradoxically suggests a cerebral vasoconstriction.
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Affiliation(s)
- Pedro M Castro
- Department Neurology, São João Hospital Center, Faculty of Medicine of University of Porto, Porto, Portugal;
| | - Rosa Santos
- Department Neurology, São João Hospital Center, Faculty of Medicine of University of Porto, Porto, Portugal
| | - João Freitas
- Autonomic Unit, São João Hospital Center, Faculty of Medicine of University of Porto, Porto, Portugal; and
| | - Ronney B Panerai
- Department of Cardiovascular Sciences and Biomedical Research Unit, University of Leicester, Leicester, United Kingdom
| | - Elsa Azevedo
- Department Neurology, São João Hospital Center, Faculty of Medicine of University of Porto, Porto, Portugal
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Robertson AD, Edgell H, Hughson RL. Assessing cerebrovascular autoregulation from critical closing pressure and resistance area product during upright posture in aging and hypertension. Am J Physiol Heart Circ Physiol 2014; 307:H124-33. [PMID: 24858843 DOI: 10.1152/ajpheart.00086.2014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Static cerebral autoregulation (sCA) is believed to be resistant to aging and hypertensive pathology. However, methods to characterize autoregulation commonly rely on beat-by-beat mean hemodynamic measures and do not consider within-beat pulse wave characteristics that are impacted by arterial stiffening. We examined the role of critical closing pressure (CrCP) and resistance area product (RAP), two measures derived from the pulse wave, across supine lying, sitting, and standing postures in young adults, normotensive older adults, and older adults with controlled and uncontrolled hypertension (N = 80). Traditional measures of sCA, using both intracranial and extracranial methods, indicated similar efficiency across all groups, but within-beat measures suggested different mechanisms of regulation. At rest, RAP was increased in hypertension compared with young adults (P < 0.001), but CrCP was similar. In contrast, the drop in CrCP was the primary regulator of change in cerebrovascular resistance upon adopting an upright posture. Both CrCP and RAP demonstrated group-by-posture interaction effects (P < 0.05), with older hypertensive adults exhibiting a rise in RAP that was absent in other groups. The posture-related swings in CrCP and RAP were related to changes in both the pulsatile and mean components of arterial pressure, independent of age, cardiac output, and carbon dioxide. Group-by-posture differences in pulse pressure were mediated in part by an attenuated heart rate response in older hypertensive adults (P = 0.002). Examination of pulsatile measures in young, elderly, and hypertensive adults identified unique differences in how cerebral blood flow is regulated in upright posture.
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Affiliation(s)
- Andrew D Robertson
- Schlegel-University of Waterloo Research Institute for Aging, Waterloo, Ontario, Canada
| | - Heather Edgell
- Schlegel-University of Waterloo Research Institute for Aging, Waterloo, Ontario, Canada
| | - Richard L Hughson
- Schlegel-University of Waterloo Research Institute for Aging, Waterloo, Ontario, Canada
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Maggio P, Salinet ASM, Robinson TG, Panerai RB. Influence of CO2 on neurovascular coupling: interaction with dynamic cerebral autoregulation and cerebrovascular reactivity. Physiol Rep 2014; 2:e00280. [PMID: 24760531 PMCID: PMC4002257 DOI: 10.1002/phy2.280] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
PaCO2 affects cerebral blood flow (CBF) and its regulatory mechanisms, but the interaction between neurovascular coupling (NVC), cerebral autoregulation (CA), and cerebrovascular reactivity to CO2 (CVR), in response to hypercapnia, is not known. Recordings of cerebral blood flow velocity (CBFv), blood pressure (BP), heart rate, and end‐tidal CO2 (EtCO2) were performed in 18 subjects during normocapnia and 5% CO2 inhalation while performing a passive motor paradigm. Together with BP and EtCO2, a gate signal to represent the effect of stimulation was used as input to a multivariate autoregressive‐moving average model to calculate their separate effects on CBFv. Hypercapnia led to a depression of dynamic CA at rest and during stimulation in both hemispheres (P <0.02) as well as impairment of the NVC response, particularly in the ipsilateral hemisphere (P <0.01). Neither hypercapnia nor the passive motor stimulation influenced CVR. Dynamic CA was not influenced by the motor paradigm during normocapnia. The CBFv step responses to each individual input (BP, EtCO2, stimulation) allowed identification of the influences of hypercapnia and neuromotor stimulation on CA, CVR, and NVC, which have not been previously described, and also confirmed the depressing effects of hypercapnia on CA and NVC. The stability of CVR during these maneuvers and the lack of influence of stimulation on dynamic CA are novel findings which deserve further investigation. Dynamic multivariate modeling can identify the complex interplay between different CBF regulatory mechanisms and should be recommended for studies involving similar interactions, such as the effects of exercise or posture on cerebral hemodynamics. The influence of hypercapnia on dynamic cerebral autoregulation (CA), CO2 vasoreactivity (CVR), and neurovascular coupling (NVC) was described based on a single recording during motor stimulation coupled to a new multivariate modeling approach. Hypercapnia led to a depression of CA at rest and during stimulation in both hemispheres as well as impairment of the NVC response. Neither hypercapnia nor the passive motor stimulation influenced CVR. Dynamic CA was not influenced by the motor paradigm during normocapnia. The stability of CVR during these maneuvers and the lack of influence of stimulation on dynamic CA are novel findings which deserve further investigation.
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Affiliation(s)
- Paola Maggio
- Neurologia Clinica, Università Campus Bio-Medico, Rome, Italy
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Willie CK. Uncoupling neurovascular coupling: putative pathways of cerebrovascular regulation? J Appl Physiol (1985) 2013; 115:1215. [DOI: 10.1152/japplphysiol.00813.2013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Christopher K. Willie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia-Okanagan, Kelowna, British Columbia, Canada
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Maggio P, Salinet ASM, Panerai RB, Robinson TG. Reply to Willie. J Appl Physiol (1985) 2013; 115:1216. [DOI: 10.1152/japplphysiol.00862.2013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Paola Maggio
- Neurologia Clinica, Università Campus Bio-Medico, Rome, Italy
| | - Angela S. M. Salinet
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom; and
| | - Ronney B. Panerai
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom; and
- National Institutes for Health Research, Biomedical Research Unit in Cardiovascular Sciences, Glenfield Hospital, Leicester, United Kingdom
| | - Thompson G. Robinson
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom; and
- National Institutes for Health Research, Biomedical Research Unit in Cardiovascular Sciences, Glenfield Hospital, Leicester, United Kingdom
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Dynamic cerebral autoregulation changes during sub-maximal handgrip maneuver. PLoS One 2013; 8:e70821. [PMID: 23967113 PMCID: PMC3743835 DOI: 10.1371/journal.pone.0070821] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 06/23/2013] [Indexed: 12/21/2022] Open
Abstract
Purpose We investigated the effect of handgrip (HG) maneuver on time-varying estimates of dynamic cerebral autoregulation (CA) using the autoregressive moving average technique. Methods Twelve healthy subjects were recruited to perform HG maneuver during 3 minutes with 30% of maximum contraction force. Cerebral blood flow velocity, end-tidal CO2 pressure (PETCO2), and noninvasive arterial blood pressure (ABP) were continuously recorded during baseline, HG and recovery. Critical closing pressure (CrCP), resistance area-product (RAP), and time-varying autoregulation index (ARI) were obtained. Results PETCO2 did not show significant changes during HG maneuver. Whilst ABP increased continuously during the maneuver, to 27% above its baseline value, CBFV raised to a plateau approximately 15% above baseline. This was sustained by a parallel increase in RAP, suggestive of myogenic vasoconstriction, and a reduction in CrCP that could be associated with metabolic vasodilation. The time-varying ARI index dropped at the beginning and end of the maneuver (p<0.005), which could be related to corresponding alert reactions or to different time constants of the myogenic, metabolic and/or neurogenic mechanisms. Conclusion Changes in dynamic CA during HG suggest a complex interplay of regulatory mechanisms during static exercise that should be considered when assessing the determinants of cerebral blood flow and metabolism.
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Salinet ASM, Robinson TG, Panerai RB. Cerebral blood flow response to neural activation after acute ischemic stroke: a failure of myogenic regulation? J Neurol 2013; 260:2588-95. [PMID: 23824356 DOI: 10.1007/s00415-013-7022-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 06/17/2013] [Accepted: 06/23/2013] [Indexed: 12/19/2022]
Abstract
We tested two hypotheses: (1) neurovascular coupling is impaired after acute ischemic stroke, (2) subcomponent analysis of cerebral blood flow velocity can reveal significant differences between acute ischemic stroke and healthy controls. This was explored through the comparison of nineteen acute ischemic stroke patients with healthy controls. Recordings of cerebral blood flow velocity, blood pressure and end-tidal CO2 were obtained during 60s of passive elbow flexion. Cerebral blood flow velocity changes were decomposed into standardized subcomponents describing the contributions of blood pressure (V BP), resistance area product (V RAP) and critical closing pressure (V CrCP). The passive paradigm led to a bilateral cerebral blood flow velocity increase in both groups, but in acute ischemic stroke the magnitude of change was significantly lower. Blood pressure increases were shown to be an important contributor to cerebral blood flow velocity response throughout the paradigm in both groups, with no significant difference between groups. The V CrCP contribution was not different between groups or hemispheres; its continuous rise during activation indicating a vasodilatory effect. On the other hand, the V RAP contribution showed significant differences (p = 0.03), thus suggesting myogenic impairment in acute ischemic stroke. Cerebral blood flow velocity responses to passive elbow flexion suggest an impairment of neurovascular coupling in acute ischemic stroke. Subcomponent analysis suggests an impairment of the myogenic pathways, giving a greater insight into the different mechanisms contributing to neurovascular coupling. Further research is needed to assess the clinical value of subcomponent analysis of neurovascular coupling and the natural history of such changes following acute ischemic stroke.
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Affiliation(s)
- Angela S M Salinet
- Department of Cardiovascular Sciences, University of Leicester, Trent Stroke Research Network Office, Victoria Building, Leicester Royal Infirmary, LE1 5WW, Leicester, UK,
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Maggio P, Salinet ASM, Panerai RB, Robinson TG. Does hypercapnia-induced impairment of cerebral autoregulation affect neurovascular coupling? A functional TCD study. J Appl Physiol (1985) 2013; 115:491-7. [PMID: 23743398 DOI: 10.1152/japplphysiol.00327.2013] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Neurovascular coupling (NVC) and dynamic cerebral autoregulation (dCA) are both impaired in the acute phase of ischemic stroke, but their reciprocal interactions are difficult to predict. To clarify these aspects, the present study explored NVC in a healthy volunteer population during a surrogate state of impaired dCA induced by hypercapnia. This study aimed to test whether hypercapnia leads to a depression of NVC through an impairment of dCA. Continuous recordings of middle cerebral arteries cerebral blood flow velocity (CBFv), blood pressure (BP), heart rate, and end-tidal CO2 were performed in 19 right-handed subjects (aged >45 yr) before, during, and after 60 s of a passive paradigm during normocapnia and hypercapnia. The CBFv response was broken down into subcomponents describing the relative contributions of BP (VBP), critical closing pressure (VCrCP), and resistance area product (VRAP). VRAP reflects myogenic activity in response to BP changes, whereas VCrCP is more indicative of metabolic control. The results revealed that hypercapnia significantly affected NVC, with significant reductions in the relative contribution of VCrCP to the paradigm-induced increase in CBFv. The present study suggests that hypercapnia impairs both dCA and NVC, probably acting through an impairment of the metabolic component of CBF control.
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Affiliation(s)
- Paola Maggio
- Neurologia Clinica, Università Campus Bio-Medico, Rome, Italy
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Zuj KA, Arbeille P, Shoemaker JK, Hughson RL. Cerebral critical closing pressure and CO2 responses during the progression toward syncope. J Appl Physiol (1985) 2013; 114:801-7. [DOI: 10.1152/japplphysiol.01181.2012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Syncope from sustained orthostasis results from cerebral hypoperfusion associated with reductions in arterial pressure at the level of the brain (BPMCA) and reductions in arterial CO2 as reflected by end-tidal values (PetCO2). It was hypothesized that reductions in PetCO2 increase cerebrovascular tone before a drop in BPMCA that ultimately leads to syncope. Twelve men (21–42 yr of age) completed an orthostatic tolerance test consisting of head-up tilt and progressive lower body negative pressure to presyncope, before and after completing 5 days of continuous head-down bed rest (HDBR). Cerebral blood velocity (CBFV), BPMCA, and PetCO2 were continuously recorded throughout the test. Cerebrovascular indicators, cerebrovascular resistance, critical closing pressure (CrCP), and resistance area product (RAP), were calculated. Comparing from supine baseline to 6–10 min after the start of tilt, there were reductions in CBFV, PetCO2, BPMCA, and CrCP, an increase in RAP, and no change in cerebrovascular resistance index. Over the final 15 min before syncope in the pre-HDBR tests, CBFV and CrCP were significantly related to changes in PetCO2 ( r = 0.69 ± 0.17 and r = 0.63 ± 0.20, respectively), and BPMCA, which was not reduced until the last minute of the test, was correlated with a reduction in RAP ( r = 0.91 ± 0.09). Post-HDBR, tilt tolerance was markedly reduced, and changes in CBFV were dominated by a greater reduction in BPMCA with no relationships to PetCO2. Therefore, pre-HDBR, changes in PetCO2 with orthostasis contributed to increases in cerebrovascular tone and reductions in CBFV during the progression toward syncope, whereas, after 5 days of HDBR, orthostatic responses were dominated by changes in BPMCA.
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Affiliation(s)
- K. A. Zuj
- University of Waterloo, Waterloo, Ontario, Canada
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