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Guo Z, Qu Y, Shen Z, Liu J, Wang Z, Sun Y, Zhang K, Chang J, Si X, Jin H, Sun X, Yang Y. Cerebral autoregulation: A reliable predictor of prognosis in patients receiving intravenous thrombolysis. CNS Neurosci Ther 2024; 30:e14748. [PMID: 38727518 PMCID: PMC11086020 DOI: 10.1111/cns.14748] [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: 10/19/2023] [Revised: 03/28/2024] [Accepted: 04/22/2024] [Indexed: 05/12/2024] Open
Abstract
AIMS To investigate the characteristics of dynamic cerebral autoregulation (dCA) after intravenous thrombolysis (IVT) and assess the relationship between dCA and prognosis. METHODS Patients with unilateral acute ischemic stroke receiving IVT were prospectively enrolled; those who did not were selected as controls. All patients underwent dCA measurements, by quantifying the phase difference (PD) and gain, at 1-3 and 7-10 days after stroke onset. Simultaneously, two dCA-based nomogram models were established to verify the predictive value of dCA for patients with mild-to-moderate stroke. RESULTS Finally, 202 patients who received IVT and 238 who did not were included. IVT was positively correlated with higher PD on days 1-3 and 7-10 after stroke onset. PD values in both sides at 1-3 days after stroke onset and in the affected side at 7-10 days after onset were independent predictors of unfavorable outcomes in patients who received IVT. Additionally, in patients with mild-to-moderate stroke who received IVT, the dCA-based nomogram models significantly improved the risk predictive ability for 3-month unfavorable outcomes. CONCLUSION IVT has a positive effect on dCA in patients with acute stroke; furthermore, dCA may be useful to predict the prognosis of patients with IVT.
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Affiliation(s)
- Zhen‐Ni Guo
- Stroke Center, Department of NeurologyThe First Hospital of Jilin UniversityChangchunChina
- Neuroscience Research Center, Department of NeurologyThe First Hospital of Jilin UniversityChangchunChina
| | - Yang Qu
- Stroke Center, Department of NeurologyThe First Hospital of Jilin UniversityChangchunChina
| | - Zi‐Duo Shen
- Stroke Center, Department of NeurologyThe First Hospital of Jilin UniversityChangchunChina
| | - Jia Liu
- Laboratory for Engineering and Scientific Computing, Institute of Advanced Computing and Digital Engineering, Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhenChina
| | - Zhong‐Xiu Wang
- Stroke Center, Department of NeurologyThe First Hospital of Jilin UniversityChangchunChina
| | - Ying‐Ying Sun
- Stroke Center, Department of NeurologyThe First Hospital of Jilin UniversityChangchunChina
| | - Ke‐Jia Zhang
- Stroke Center, Department of NeurologyThe First Hospital of Jilin UniversityChangchunChina
| | - Junlei Chang
- Center for Protein and Cell‐based Drugs, Institute of Biomedicine and Biotechnology, Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhenChina
| | - Xiang‐Kun Si
- Stroke Center, Department of NeurologyThe First Hospital of Jilin UniversityChangchunChina
| | - Hang Jin
- Stroke Center, Department of NeurologyThe First Hospital of Jilin UniversityChangchunChina
| | - Xin Sun
- Stroke Center, Department of NeurologyThe First Hospital of Jilin UniversityChangchunChina
| | - Yi Yang
- Stroke Center, Department of NeurologyThe First Hospital of Jilin UniversityChangchunChina
- Neuroscience Research Center, Department of NeurologyThe First Hospital of Jilin UniversityChangchunChina
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Kostoglou K, Bello-Robles F, Brassard P, Chacon M, Claassen JA, Czosnyka M, Elting JW, Hu K, Labrecque L, Liu J, Marmarelis VZ, Payne SJ, Shin DC, Simpson D, Smirl J, Panerai RB, Mitsis GD. Time-domain methods for quantifying dynamic cerebral blood flow autoregulation: Review and recommendations. A white paper from the Cerebrovascular Research Network (CARNet). J Cereb Blood Flow Metab 2024:271678X241249276. [PMID: 38688529 DOI: 10.1177/0271678x241249276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
Cerebral Autoregulation (CA) is an important physiological mechanism stabilizing cerebral blood flow (CBF) in response to changes in cerebral perfusion pressure (CPP). By maintaining an adequate, relatively constant supply of blood flow, CA plays a critical role in brain function. Quantifying CA under different physiological and pathological states is crucial for understanding its implications. This knowledge may serve as a foundation for informed clinical decision-making, particularly in cases where CA may become impaired. The quantification of CA functionality typically involves constructing models that capture the relationship between CPP (or arterial blood pressure) and experimental measures of CBF. Besides describing normal CA function, these models provide a means to detect possible deviations from the latter. In this context, a recent white paper from the Cerebrovascular Research Network focused on Transfer Function Analysis (TFA), which obtains frequency domain estimates of dynamic CA. In the present paper, we consider the use of time-domain techniques as an alternative approach. Due to their increased flexibility, time-domain methods enable the mitigation of measurement/physiological noise and the incorporation of nonlinearities and time variations in CA dynamics. Here, we provide practical recommendations and guidelines to support researchers and clinicians in effectively utilizing these techniques to study CA.
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Affiliation(s)
- Kyriaki Kostoglou
- Department of Electrical and Computer Engineering, McGill University, Montreal, QC, Canada
- Institute of Neural Engineering, Graz University of Technology, Graz, Austria
| | - Felipe Bello-Robles
- Departamento de Ingeniería Informática, Universidad de Santiago de Chile, Santiago, Chile
| | - Patrice Brassard
- Department of Kinesiology, Faculty of Medicine, Université Laval, Quebec, QC, Canada
- Research Center of the Institut universitaire de cardiologie et de pneumologie de Québec, Quebec, QC, Canada
| | - Max Chacon
- Departamento de Ingeniería Informática, Universidad de Santiago de Chile, Santiago, Chile
| | - Jurgen Ahr Claassen
- Department of Geriatrics, Radboud University Medical Center, Research Institute for Medical Innovation and Donders Institute, Nijmegen, The Netherlands
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM), Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
| | - Marek Czosnyka
- Department of Clinical Neurosciences, Neurosurgery Department, University of Cambridge, Cambridge, UK
| | - Jan-Willem Elting
- Department of Neurology and Clinical Neurophysiology, University Medical Center Groningen, Groningen, The Netherlands
| | - Kun Hu
- Medical Biodynamics Program, Division of Sleep and Circadian Disorders, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
- Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
| | - Lawrence Labrecque
- Department of Kinesiology, Faculty of Medicine, Université Laval, Quebec, QC, Canada
- Research Center of the Institut universitaire de cardiologie et de pneumologie de Québec, Quebec, QC, Canada
| | - Jia Liu
- Laboratory for Engineering and Scientific Computing, Institute of Advanced Computing and Digital Engineering, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China
| | - Vasilis Z Marmarelis
- Department Biomedical Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, CA, USA
| | - Stephen J Payne
- Institute of Applied Mechanics, National Taiwan University, Taipei, Taiwan
| | - Dae Cheol Shin
- Department Biomedical Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, CA, USA
| | - David Simpson
- Institute of Sound and Vibration Research, University of Southampton, Southampton, UK
| | - Jonathan Smirl
- Cerebrovascular Concussion Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
- Sport Injury Prevention Research Centre, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Ronney B Panerai
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM), Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
- NIHR Leicester Biomedical Research Centre, British Heart Foundation, Glenfield Hospital, Leicester, UK
| | - Georgios D Mitsis
- Department of Bioengineering, McGill University, Montreal, QC, Canada
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Scheuermann BC, Parr SK, Schulze KM, Kunkel ON, Turpin VG, Liang J, Ade CJ. Associations of Cerebrovascular Regulation and Arterial Stiffness With Cerebral Small Vessel Disease: A Systematic Review and Meta-Analysis. J Am Heart Assoc 2023; 12:e032616. [PMID: 37930079 PMCID: PMC10727345 DOI: 10.1161/jaha.123.032616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Accepted: 10/24/2023] [Indexed: 11/07/2023]
Abstract
BACKGROUND Cerebral small vessel disease (cSVD) is a major contributing factor to ischemic stroke and dementia. However, the vascular pathologies of cSVD remain inconclusive. The aim of this systematic review and meta-analysis was to characterize the associations between cSVD and cerebrovascular reactivity (CVR), cerebral autoregulation, and arterial stiffness (AS). METHODS AND RESULTS MEDLINE, Web of Science, and Embase were searched from inception to September 2023 for studies reporting CVR, cerebral autoregulation, or AS in relation to radiological markers of cSVD. Data were extracted in predefined tables, reviewed, and meta-analyses performed using inverse-variance random effects models to determine pooled odds ratios (ORs). A total of 1611 studies were identified; 142 were included in the systematic review, of which 60 had data available for meta-analyses. Systematic review revealed that CVR, cerebral autoregulation, and AS were consistently associated with cSVD (80.4%, 78.6%, and 85.4% of studies, respectively). Meta-analysis in 7 studies (536 participants, 32.9% women) revealed a borderline association between impaired CVR and cSVD (OR, 2.26 [95% CI, 0.99-5.14]; P=0.05). In 37 studies (27 952 participants, 53.0% women) increased AS, per SD, was associated with cSVD (OR, 1.24 [95% CI, 1.15-1.33]; P<0.01). Meta-regression adjusted for comorbidities accounted for one-third of the AS model variance (R2=29.4%, Pmoderators=0.02). Subgroup analysis of AS studies demonstrated an association with white matter hyperintensities (OR, 1.42 [95% CI, 1.18-1.70]; P<0.01). CONCLUSIONS The collective findings of the present systematic review and meta-analyses suggest an association between cSVD and impaired CVR and elevated AS. However, longitudinal investigations into vascular stiffness and regulatory function as possible risk factors for cSVD remain warranted.
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Affiliation(s)
| | - Shannon K. Parr
- Department of KinesiologyKansas State UniversityManhattanKSUSA
| | | | | | | | - Jia Liang
- Department of Biostatistics, St. Jude Children’s Research HospitalMemphisTNUSA
| | - Carl J. Ade
- Department of KinesiologyKansas State UniversityManhattanKSUSA
- Department of Physician’s Assistant Studies, Kansas State UniversityManhattanKSUSA
- Johnson Cancer Research CenterKansas State UniversityManhattanKSUSA
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Sheriff FG, Ahmad A, Inam ME, Khatri R, Maud A, Rodriguez GJ. A systematic review on the assessment of cerebral autoregulation in patients with Large Vessel Occlusion. Front Neurol 2023; 14:1287873. [PMID: 38046584 PMCID: PMC10693431 DOI: 10.3389/fneur.2023.1287873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2023] [Accepted: 11/02/2023] [Indexed: 12/05/2023] Open
Abstract
As the majority of large vessel occlusion (LVO) patients are not treated with revascularization therapies or efficiently revascularized, complementary management strategies are needed. In this article we explore the importance of cerebral autoregulation (CA) assessment in the prediction and/or modification of infarct growth and hemorrhagic transformation. In patients with LVO, these are important factors that affect prognosis. A systematic search of the PubMed, EMBASE databases and a targeted Google search was conducted, resulting in the inclusion of 34 relevant articles. There is an agreement that CA is impaired in patients with LVO; several factors have been identified such as time course, revascularization status, laterality, disease subtype and location, some of which may be potentially modifiable and affect outcomes. The personalized CA assessment of these patients suggests potential for better understanding of the inter-individual variability. Further research is needed for the development of more accurate, noninvasive techniques for continuous monitoring and personalized thresholds for CA.
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Affiliation(s)
- Faheem G. Sheriff
- Department of Neurology, Section of Interventional Neurology, Texas Tech University Health Sciences Center El Paso, El Paso, TX, United States
| | | | - Mehmet E. Inam
- University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Rakesh Khatri
- Department of Neurology, Section of Interventional Neurology, Texas Tech University Health Sciences Center El Paso, El Paso, TX, United States
| | - Alberto Maud
- Department of Neurology, Section of Interventional Neurology, Texas Tech University Health Sciences Center El Paso, El Paso, TX, United States
| | - Gustavo J. Rodriguez
- Department of Neurology, Section of Interventional Neurology, Texas Tech University Health Sciences Center El Paso, El Paso, TX, United States
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Gao J, Yang C, Ji Q, Li J. Effect of remimazolam versus propofol for the induction of general anesthesia on cerebral blood flow and oxygen saturation in elderly patients undergoing carotid endarterectomy. BMC Anesthesiol 2023; 23:153. [PMID: 37142971 PMCID: PMC10157955 DOI: 10.1186/s12871-023-02095-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 04/18/2023] [Indexed: 05/06/2023] Open
Abstract
BACKGROUND This study was conducted to investigate the effects and safety of remimazolam versus propofol on cerebral oxygen saturation and cerebral hemodynamics during the induction of general anesthesia in patients receiving carotid endarterectomy (CEA), so as to provide theoretical basis for better clinical application of remimazolam. METHODS Forty-three patients (60-75 years old) with carotid artery stenosis (carotid artery stenosis greater than 70%) were randomly divided into the remimazolam group (R group) and the propofol group (P group). Anesthesia was induced with remimazolam (0.3 mg/kg) or propofol (1.5-2 mg/kg) individually. At time of admission (T0), post-anesthesia induction (T1), consciousness disappears (T2), 1 min after loss of consciousness (T3), 2 min after loss of consciousness (T4) and pre-endotracheal intubation (T5), measurement in patients with regional cerebral oxygen saturation (SrO2), average blood flow velocity (Vm), resistance index (RI), mean arterial pressure (MAP), heart rate (HR) and cardiac index (CI) were recorded. RESULTS SrO2 increased significantly in both groups after induction of anesthesia compared with baseline (P < 0.05) and decreased after loss of consciousness (P < 0.05). There was no difference in the mean value of the relative changes in SrO2 between the groups. Meanwhile, the Vm, RI, HR and CI of each time point between two groups showed no statistically significant difference (P > 0.05) while MAP in group P at T5 was lower than that in group R individually(P < 0.05). In each group, Vm, HR, CI and MAP at T2-T5 were all significantly reduced compared with T1, with statistically differences(P < 0.05). Specifically, there was no difference of RI at each time between or within groups(P > 0.05). CONCLUSIONS Our study revealed that remimazolam can be administered safely and effectively during the induction of general anesthesia for carotid endarterectomy in elder population and it demonstrated superiority in hemodynamic changes compared with propofol. CLINICAL TRIAL REGISTRATION This trial was retrospectively registered with the Chinese Clinical Trial Registry. REGISTRATION NUMBER ChiCTR2300070370. Date of registration: April 11, 2023.
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Affiliation(s)
- Jianling Gao
- Department of Critical Care Medicine, Dushu Lake Hospital Affiliated to Soochow University, Suzhou, Jiangsu, China
- Department of Critical Care Medicine, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
| | - Chengdi Yang
- Department of Critical Care Medicine, Dushu Lake Hospital Affiliated to Soochow University, Suzhou, Jiangsu, China
| | - Qiuyuan Ji
- Department of Anesthesiology, Dushu Lake Hospital Affiliated to Soochow University, Suzhou, Jiangsu, China
| | - Jian Li
- Department of Anesthesiology, Dushu Lake Hospital Affiliated to Soochow University, Suzhou, Jiangsu, China.
- Department of Anesthesiology, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China.
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Liu M, He E, Fu X, Gong S, Han Y, Deng F. Cerebral blood flow self-regulation in depression. J Affect Disord 2022; 302:324-331. [PMID: 35032508 DOI: 10.1016/j.jad.2022.01.057] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 12/21/2021] [Accepted: 01/11/2022] [Indexed: 11/30/2022]
Abstract
BACKGROUND Depression is a common neuropsychiatric disease with a high prevalence rate. Sleep problems, memory decline, dizziness and headaches are the most common neurological symptoms in depressed patients. Abnormality of cerebral blood flow (CBF) has been observed in depressive patients, but those patients did not have intracranial structural damage. Both of those phenomena might be related to cerebral blood flow self-regulation (CBFSR: cerebral blood flow self-regulation). CBFSR can maintain CBF relatively stable in response to changes in neurological and metabolic factors. Therefore, this review aimed to discuss CBFSR in depression. METHODS We searched for keywords such as "depression", "cerebral blood flow", "cerebral autoregulation", "cerebrovascular reactivity" and the words related to depression. We analyzed whether there is a change in the CBFSR in depression, further explored whether there is a relationship between the pathogenesis of depression and the CBFSR, and discussed the possible mechanism of impaired CBFSR in patients with depression. RESULTS Discovered by the literature review, CBFSR is significantly impaired in depressed patients. The level of circulating markers of endothelial dysfunction, nitric oxide, inflammatory cytokines, glucocorticoid and monoamine neurotransmitters is mostly abnormal in depression, which affected the CBFSR to varying degrees. LIMITATIONS Limitations include the small number of direct studies about depression and CBFSR mechanisms. CONCLUSION CBFSR is impaired in depression. The underlying mechanisms include endothelial dysfunction, overactivation of microglia and changes of cytokines, hyperactivation of the HPA axis, increased oxidative stress, monoamine neurotransmitter disorders, etc. These deepened our understanding of the clinical symptoms of depressed patients.
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Affiliation(s)
- Min Liu
- Department of Neurology, The First Hospital of Jilin University, No.1, Xinmin Street, Changchun, China
| | - Enling He
- Department of Neurology, The First Hospital of Jilin University, No.1, Xinmin Street, Changchun, China
| | - Xiyao Fu
- Department of Neurology, The First Hospital of Jilin University, No.1, Xinmin Street, Changchun, China
| | - Sizhu Gong
- Department of Neurology, The First Hospital of Jilin University, No.1, Xinmin Street, Changchun, China
| | - Yue Han
- Department of Neurology, The First Hospital of Jilin University, No.1, Xinmin Street, Changchun, China
| | - Fang Deng
- Department of Neurology, The First Hospital of Jilin University, No.1, Xinmin Street, Changchun, China.
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Yao MX, Qiu DH, Zheng WC, Zhao JH, Yin HP, Liu YL, Chen YK. Effects of Early-Stage Blood Pressure Variability on the Functional Outcome in Acute Ischemic Stroke Patients With Symptomatic Intracranial Artery Stenosis or Occlusion Receiving Intravenous Thrombolysis. Front Neurol 2022; 13:823494. [PMID: 35345407 PMCID: PMC8957087 DOI: 10.3389/fneur.2022.823494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Accepted: 02/08/2022] [Indexed: 12/03/2022] Open
Abstract
Background Studies exploring the relationship between blood pressure (BP) fluctuations and outcome in acute ischemic stroke (AIS) patients treated with intravenous thrombolysis (IVT) are limited. We aimed to investigate the influence of blood pressure variability (BPV) during the first 24 h after IVT on early neurological deterioration (END) and 3-month outcome after IVT in terms of different stroke subtypes. Methods Clinical data from consecutive AIS patients who received IVT were retrospectively analyzed. The hourly systolic BP of all patients were recorded during the first 24 h following IVT. We calculated three systolic BPV parameters, including coefficient of variability (CV), standard deviation of mean BP (SD) and successive variation (SV), within the first 6, 12, and 24 h after IVT. END was defined as neurological deterioration with an increase in the National Institutes of Health Stroke Scale (NIHSS) score ≥ 4 points within the first 72 h after admission. Follow-up was performed at 90 days after onset, and favorable and poor outcomes were defined as a modified Rankin Scale scores (mRS) of ≤1 or ≥2, respectively. Results A total of 339 patients, which were divided into those with (intracranial artery stenosis or occlusion group, SIASO group) and without (non-SIASO group) SIASO, were included. Among them, 110 patients (32.4%) were with SIASO. Patients in SIASO group had higher NIHSS on admission and difference in term of mRS at 90 days compared with non-SIASO group (P < 0.001). In SIASO group, patients in favorable outcome group were younger and had lower NIHSS on admission, lower SV-24 h (14.5 ± 4.3 vs. 11.8 ± 3.2, respectively) and lower SD-24 h (12.7 ± 3.8 vs. 10.9 ± 3.3, respectively), compared with patients with poor outcome (all P < 0.05). In the multivariable logistic regression analysis, compared with the lowest SV (SV < 25% quartile), SV50−75% [odds ratio (OR) = 4.449, 95% confidence interval (CI) = 1.231–16.075, P = 0.023] and SV>75% (OR = 8.676, 95% CI = 1.892–39.775, P = 0.005) were significantly associated with poor outcome at 3 months in patients with SIASO, adjusted for age, NIHSS on admission and atrial fibrillation. No BPV parameters were associated with END in SIASO group. In non-SIASO group, there were no significant association between BPV patterns and END or 90-day outcome. Conclusions SV-24 h had a negative relationship with 3-month outcome in AIS patients with SIASO treated with IVT, indicating that BPV may affect the outcome of AIS.
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Porta A, Gelpi F, Bari V, Cairo B, De Maria B, Tonon D, Rossato G, Ranucci M, Faes L. Categorizing the Role of Respiration in Cardiovascular and Cerebrovascular Variability Interactions. IEEE Trans Biomed Eng 2021; 69:2065-2076. [PMID: 34905489 DOI: 10.1109/tbme.2021.3135313] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Respiration disturbs cardiovascular and cerebrovascular controls but its role is not fully elucidated. METHODS Respiration can be classified as a confounder if its observation reduces the strength of the causal relationship from source to target. Respiration is a suppressor if the opposite situation holds. We prove that a confounding/suppression (C/S) test can be accomplished by evaluating the sign of net redundancy/synergy balance in the predictability framework based on multivariate autoregressive modelling. In addition, we suggest that, under the hypothesis of Gaussian processes, the C/S test can be given in the transfer entropy decomposition framework as well. Experimental protocols: We applied the C/S test to variability series of respiratory movements, heart period, systolic arterial pressure, mean arterial pressure, and mean cerebral blood flow recorded in 17 pathological individuals (age: 648 yrs; 17 males) before and after induction of propofol-based general anesthesia prior to coronary artery bypass grafting, and in 13 healthy subjects (age: 278 yrs; 5 males) at rest in supine position and during head-up tilt with a table inclination of 60. RESULTS Respiration behaved systematically as a confounder for cardiovascular and cerebrovascular controls. In addition, its role was affected by propofol-based general anesthesia but not by a postural stimulus of limited intensity. CONCLUSION The C/S test can be fruitfully exploited to categorize the role of respiration over causal variability interactions. SIGNIFICANCE The application of the C/S test could favor the comprehension of the role of respiration in cardiovascular and cerebrovascular regulations.
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Claassen JAHR, Thijssen DHJ, Panerai RB, Faraci FM. Regulation of cerebral blood flow in humans: physiology and clinical implications of autoregulation. Physiol Rev 2021; 101:1487-1559. [PMID: 33769101 PMCID: PMC8576366 DOI: 10.1152/physrev.00022.2020] [Citation(s) in RCA: 295] [Impact Index Per Article: 98.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Brain function critically depends on a close matching between metabolic demands, appropriate delivery of oxygen and nutrients, and removal of cellular waste. This matching requires continuous regulation of cerebral blood flow (CBF), which can be categorized into four broad topics: 1) autoregulation, which describes the response of the cerebrovasculature to changes in perfusion pressure; 2) vascular reactivity to vasoactive stimuli [including carbon dioxide (CO2)]; 3) neurovascular coupling (NVC), i.e., the CBF response to local changes in neural activity (often standardized cognitive stimuli in humans); and 4) endothelium-dependent responses. This review focuses primarily on autoregulation and its clinical implications. To place autoregulation in a more precise context, and to better understand integrated approaches in the cerebral circulation, we also briefly address reactivity to CO2 and NVC. In addition to our focus on effects of perfusion pressure (or blood pressure), we describe the impact of select stimuli on regulation of CBF (i.e., arterial blood gases, cerebral metabolism, neural mechanisms, and specific vascular cells), the interrelationships between these stimuli, and implications for regulation of CBF at the level of large arteries and the microcirculation. We review clinical implications of autoregulation in aging, hypertension, stroke, mild cognitive impairment, anesthesia, and dementias. Finally, we discuss autoregulation in the context of common daily physiological challenges, including changes in posture (e.g., orthostatic hypotension, syncope) and physical activity.
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Affiliation(s)
- Jurgen A H R Claassen
- Department of Geriatrics, Radboud University Medical Center, Donders Institute for Brain, Cognition, and Behaviour, Nijmegen, The Netherlands
| | - Dick H J Thijssen
- Department of Physiology, Radboud Institute for Health Sciences, Nijmegen, The Netherlands
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - Ronney B Panerai
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- >National Institute for Health Research Leicester Biomedical Research Centre, University of Leicester, Leicester, United Kingdom
| | - Frank M Faraci
- Departments of Internal Medicine, Neuroscience, and Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, Iowa
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Impaired cerebrovascular reactivity is associated with recurrent stroke in patients with severe intracranial arterial stenosis: A C02 BOLD fMRI study. J Neuroradiol 2021; 48:339-345. [DOI: 10.1016/j.neurad.2020.04.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 04/08/2020] [Accepted: 04/28/2020] [Indexed: 11/20/2022]
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11
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Chen J, Dong P, Dong K, Mo D, Wang Y, Zhao X, Wang Y, Gong X. Improvement of exhausted cerebral autoregulation in patients with idiopathic intracranial hypertension benefit of venous sinus stenting. Physiol Meas 2021; 42. [PMID: 34293729 DOI: 10.1088/1361-6579/ac172c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 07/22/2021] [Indexed: 02/06/2023]
Abstract
Objective.To evaluate the cerebral autoregulation (CA) in idiopathic intracranial hypertension (IIH) patients with transfer function analysis, and to explore its improvement after venous sinus stenting.Approach. In total, 15 consecutive IIH patients with venous sinus stenosis and 15 controls were recruited. All the patients underwent digital subtraction angiography and venous manometry. Venous sinus stenting was performed for IIH patients with a trans-stenosis pressure gradient ≥8 mmHg. CA was assessed before and after the operation with transfer function analysis, by using the spontaneous oscillations of the cerebral blood flow velocity in the bilateral middle cerebral artery and blood pressure.Main results. Compared with controls, the autoregulatory parameters, phase shift and rate of recovery, were both significantly lower in IIH patients [(57.94° ± 23.22° versus 34.59° ± 24.15°,p < 0.001; (39.87 ± 21.95) %/s versus (20.56 ± 46.66) %/s,p= 0.045, respectively). In total, six patients with bilateral transverse or sigmoid sinus stenosis received venous sinus stenting, in whom, the phase shift significantly improved after venous sinus stenting (39.62° ± 20.26° versus 22.79° ± 19.96°,p = 0.04).Significance. The study revealed that dynamic CA was impaired in IIH patients and was improved after venous sinus stenting. CA assessment has the potential to be used for investigating the hemodynamics in IIH patients.
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Affiliation(s)
- Jie Chen
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, People's Republic of China
| | - Pei Dong
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, People's Republic of China
| | - Kehui Dong
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, People's Republic of China
| | - Dapeng Mo
- Neurointervention Center, Beijing Tiantan Hospital, Capital Medical University, Beijing, People's Republic of China
| | - Yilong Wang
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, People's Republic of China
| | - Xingquan Zhao
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, People's Republic of China
| | - Yongjun Wang
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, People's Republic of China
| | - Xiping Gong
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, People's Republic of China
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12
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Nogueira RC, Beishon L, Bor-Seng-Shu E, Panerai RB, Robinson TG. Cerebral Autoregulation in Ischemic Stroke: From Pathophysiology to Clinical Concepts. Brain Sci 2021; 11:511. [PMID: 33923721 PMCID: PMC8073938 DOI: 10.3390/brainsci11040511] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 04/02/2021] [Accepted: 04/09/2021] [Indexed: 11/17/2022] Open
Abstract
Ischemic stroke (IS) is one of the most impacting diseases in the world. In the last decades, new therapies have been introduced to improve outcomes after IS, most of them aiming for recanalization of the occluded vessel. However, despite this advance, there are still a large number of patients that remain disabled. One interesting possible therapeutic approach would be interventions guided by cerebral hemodynamic parameters such as dynamic cerebral autoregulation (dCA). Supportive hemodynamic therapies aiming to optimize perfusion in the ischemic area could protect the brain and may even extend the therapeutic window for reperfusion therapies. However, the knowledge of how to implement these therapies in the complex pathophysiology of brain ischemia is challenging and still not fully understood. This comprehensive review will focus on the state of the art in this promising area with emphasis on the following aspects: (1) pathophysiology of CA in the ischemic process; (2) methodology used to evaluate CA in IS; (3) CA studies in IS patients; (4) potential non-reperfusion therapies for IS patients based on the CA concept; and (5) the impact of common IS-associated comorbidities and phenotype on CA status. The review also points to the gaps existing in the current research to be further explored in future trials.
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Affiliation(s)
- Ricardo C. Nogueira
- Neurology Department, School of Medicine, Hospital das Clinicas, University of São Paulo, São Paulo 01246-904, Brazil;
- Department of Neurology, Hospital Nove de Julho, São Paulo 01409-002, Brazil
| | - Lucy Beishon
- Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester LE2 7LX, UK; (L.B.); (R.B.P.); (T.G.R.)
| | - Edson Bor-Seng-Shu
- Neurology Department, School of Medicine, Hospital das Clinicas, University of São Paulo, São Paulo 01246-904, Brazil;
| | - Ronney B. Panerai
- Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester LE2 7LX, UK; (L.B.); (R.B.P.); (T.G.R.)
- National Institute for Health Research (NIHR) Leicester Biomedical Research Centre, University of Leicester, Leicester LE5 4PW, UK
| | - Thompson G. Robinson
- Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester LE2 7LX, UK; (L.B.); (R.B.P.); (T.G.R.)
- National Institute for Health Research (NIHR) Leicester Biomedical Research Centre, University of Leicester, Leicester LE5 4PW, UK
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Liu J, Guo ZN, Simpson D, Zhang P, Liu C, Song JN, Leng X, Yang Y. A Data-Driven Approach to Transfer Function Analysis for Superior Discriminative Power: Optimized Assessment of Dynamic Cerebral Autoregulation. IEEE J Biomed Health Inform 2021; 25:909-921. [PMID: 32780704 DOI: 10.1109/jbhi.2020.3015907] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Transfer function analysis (TFA) is extensively used to assess human physiological functions. However, extracting parameters from TFA is not usually optimized for detecting impaired function. In this study, we propose to use data-driven approaches to improve the performance of TFA in assessing blood flow control in the brain (dynamic cerebral autoregulation, dCA). Data were collected from two distinct groups of subjects deemed to have normal and impaired dCA. Continuous arterial blood pressure (ABP) and cerebral blood flow velocity (CBFV) were simultaneously recorded for approximately 10 mins in 82 subjects (including 41 healthy controls) to give 328 labeled samples of the TFA variables. The recordings were further divided into 4,294 short data segments to generate 17,176 unlabeled samples of the TFA variables. We optimized TFA post-processing with a generic semi-supervised learning strategy and a novel semi-supervised stacked ensemble learning (SSEL) strategy for classification into normal and impaired dCA. The generic strategy led to a performance with no significant difference to that of the conventional dCA analysis methods, whereas the proposed new strategy boosted the performance of TFA to an accuracy of 93.3%. To our knowledge, this is the best dCA discrimination performance obtained to date and the first attempt at optimizing TFA through machine learning techniques. Equivalent methods can potentially also be applied to assessing a wide spectrum of other human physiological functions.
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14
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Chen JJ, Gauthier CJ. The Role of Cerebrovascular-Reactivity Mapping in Functional MRI: Calibrated fMRI and Resting-State fMRI. Front Physiol 2021; 12:657362. [PMID: 33841190 PMCID: PMC8027080 DOI: 10.3389/fphys.2021.657362] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 03/02/2021] [Indexed: 12/14/2022] Open
Abstract
Task and resting-state functional MRI (fMRI) is primarily based on the same blood-oxygenation level-dependent (BOLD) phenomenon that MRI-based cerebrovascular reactivity (CVR) mapping has most commonly relied upon. This technique is finding an ever-increasing role in neuroscience and clinical research as well as treatment planning. The estimation of CVR has unique applications in and associations with fMRI. In particular, CVR estimation is part of a family of techniques called calibrated BOLD fMRI, the purpose of which is to allow the mapping of cerebral oxidative metabolism (CMRO2) using a combination of BOLD and cerebral-blood flow (CBF) measurements. Moreover, CVR has recently been shown to be a major source of vascular bias in computing resting-state functional connectivity, in much the same way that it is used to neutralize the vascular contribution in calibrated fMRI. Furthermore, due to the obvious challenges in estimating CVR using gas challenges, a rapidly growing field of study is the estimation of CVR without any form of challenge, including the use of resting-state fMRI for that purpose. This review addresses all of these aspects in which CVR interacts with fMRI and the role of CVR in calibrated fMRI, provides an overview of the physiological biases and assumptions underlying hypercapnia-based CVR and calibrated fMRI, and provides a view into the future of non-invasive CVR measurement.
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Affiliation(s)
- J Jean Chen
- Baycrest Centre for Geriatric Care, Rotman Research Institute, Toronto, ON, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Claudine J Gauthier
- Department of Physics, Concordia University, Montreal, QC, Canada.,Montreal Heart Institute, Montreal, QC, Canada
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15
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Delay of cerebral autoregulation in traumatic brain injury patients. Clin Neurol Neurosurg 2021; 202:106478. [PMID: 33454499 DOI: 10.1016/j.clineuro.2021.106478] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 01/04/2021] [Accepted: 01/05/2021] [Indexed: 11/22/2022]
Abstract
INTRODUCTION Adequate cerebral perfusion prevents secondary insult after traumatic brain injury (TBI). Cerebral autoregulation (CAR) keeps cerebral blood flow (CBF) constant when arterial blood pressure (ABP) changes. Aim of the study was to evaluate the existence of delayed CAR in TBI patients and its possible association with outcome. METHODS We retrospectively analysed TBI patients. Flow velocity (FV) in middle cerebral artery, invasive intra-cranial pressure (ICP) and ABP were recorded. Cerebral perfusion pressure (CPP) was calculated as ABP - ICP. Mean flow index (Mx) > 0.3 defined altered CAR. Samples from patients with altered CAR were further analysed: FV signal was shifted backward relative to CPP; Mx was calculated after each shift (MxD). Mx > 0.3 plus MxD ≤ 0.3 defined delayed CAR. Favourable outcome (FO) at 6 months was defined as Glasgow Outcome Scale 4-5. RESULTS 154 patients were included. GCS was 6 [4-9], ICP was 14 [9-20] mmHg. Data on 6 months outcome were available for 131 patients: 104/131 patients (79 %) were alive; GOS was 4 [3-5]; 70/131 (53 %) had FO. Mx was 0.07 [-0.19 to 0.28] overall. Mx was lower in patients with FO compared others (0.00 [-0.21 to 0.20] vs 0.17 [-0.12 to 0.37], p = 0.02). 118 (77 %) patients had intact CAR and 36 (23 %) patients had altered CAR; 23 patients - 15 % of the general cohort and 64 % of patients with altered CAR - had delayed CAR. Delay in the autoregulatory response was 2 [1-4] seconds. 80/98 (82 %) of patients with intact CAR survived, compared to 16/21 (76 %) with delayed and 8/12 (67 %) with altered CAR (p = 0.20). 80/98 (58 %) patients with intact, 10/21 (48 %) patients with delayed and 3/12 (25 %) patients with altered CAR had FO (p = 0.03). CONCLUSION A subgroup of TBI patients with delayed CAR was identified. Delayed CAR was associated with better neurological outcome than altered CAR.
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Chen J, Liu J, Dong K, Wang Y, Zhao X, Wang Y, Gong X. Impaired Dynamic Cerebral Autoregulation in Cerebral Venous Thrombosis. Front Neurol 2020; 11:570306. [PMID: 33240198 PMCID: PMC7680926 DOI: 10.3389/fneur.2020.570306] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 10/19/2020] [Indexed: 11/29/2022] Open
Abstract
Background: Cerebral autoregulation is crucial in traumatic brain injury, which might be used for determining the optimal intracranial pressure. Cerebral venous thrombosis (CVT) is a cerebral vascular disease with features of high intracranial pressure. However, the autoregulatory mechanism of CVT remains unknown. We aimed to investigate the capacity of cerebral autoregulation in patients with CVT. Methods: This study consecutively enrolled 23 patients with CVT and 16 controls from December 2018 to May 2019. Cerebral autoregulation was assessed by transfer function analysis (rate of recovery/phase/gain) using the spontaneous oscillations of the cerebral blood flow velocity and arterial blood pressure. Results: In total, 76 middle cerebral arteries (MCAs) were investigated, including 44 MCAs in patients with CVT and 32 normal ones. The phase shift estimated in patients with CVT was significantly different from that of the controls (37.37 ± 36.53 vs. 54.00 ± 26.78, p = 0.03). The rate of recovery and gain in patients with CVT were lower than those in controls but without statistical significance. Conclusion: To our knowledge, this is the first time that a study has indicated that patients with CVT were more likely to have impaired cerebral autoregulation. Hence, cautious blood pressure control is required in such patients to prevent hyper- or hypoperfusion.
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Affiliation(s)
- Jie Chen
- Vascular Neurology, Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Jia Liu
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Kehui Dong
- Vascular Neurology, Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Yilong Wang
- Vascular Neurology, Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Xingquan Zhao
- Vascular Neurology, Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Yongjun Wang
- Vascular Neurology, Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Xiping Gong
- Vascular Neurology, Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
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17
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Volkova MV, Boyarintsev VV, Trofimenko AV, Biryukov SA, Gorina EV, Filkov GI, Durymanov MO. Adaptation of Bio-Layer Interferometry for Quantitative Assessment of the Vascular Endothelial Growth Factor Content in Cell-Conditioned Culture Medium. Biophysics (Nagoya-shi) 2020. [DOI: 10.1134/s0006350920060226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Lam MY, Haunton VJ, Nath M, Panerai RB, Robinson TG. The effect of head positioning on cerebral hemodynamics: Experiences in mild ischemic stroke. J Neurol Sci 2020; 419:117201. [PMID: 33137635 DOI: 10.1016/j.jns.2020.117201] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 09/30/2020] [Accepted: 10/19/2020] [Indexed: 12/01/2022]
Abstract
BACKGROUND AND PURPOSE It is generally agreed that optimal head positioning is an important consideration in acute stroke management regime. However, there is limited literature investigating the effect of head positioning changes on cerebrovascular physiology in acute ischemic stroke (AIS). We aim to assess cerebral autoregulation (CA) and associated hemodynamic responses during gradual head positioning (GHP) changes, between AIS and controls. METHODS Cerebral blood flow velocity (CBFV, transcranial Doppler), blood pressure (BP, Finometer) and end-tidal CO2 (capnography) were recorded between lying flat (0°) and sitting up (30°) head position, in 16 controls (8 women, mean age 57 ± 16 yrs) and 15 AIS patients (7 women, 69 ± 8 yrs). AIS patients carried out three visits at 13.3 ± 6.9 h, 4.8 ± 3.2 days and 93.9 ± 11.5 days from symptom onset, respectively. RESULTS AIS patients were significantly hypertensive (p = 0.005), hypocapnic (p < 0.001), and had lower CBFV (p = 0.02) compared to controls, in both head positions. When comparing 5-min FLAT to SIT head position, reductions in BP (both AIS and controls, p < 0.001) and CBFV (controls only: dominant hemisphere p = 0.001 and non-dominant hemisphere p = 0.05) were demonstrated. Of note, a reduction in autoregulation index was observed in AIS, after 5-min SIT head positioning, at all 3 visits (p = 0.018). CONCLUSION Key hemodynamic changes were demonstrated when the head position changes from 5-min FLAT to SIT head position (GHP) in mildly affected stroke patients. Importantly, these were associated with non-significant changes in CBFV but reduced measures of CA following AIS, which may be relevant in determining the optimal head position and the ideal timing of mobilisation. Clinical Trial Registration - URL: http://www.clinicaltrials.gov. Unique Identifier: NCT02932540.
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Affiliation(s)
- Man Y Lam
- Department of Cardiovascular Sciences, University of Leicester, LE1 5WW Leicester, United Kingdom.
| | - Victoria J Haunton
- Department of Cardiovascular Sciences, University of Leicester, LE1 5WW Leicester, United Kingdom; National Institutes for Health Research Leicester Biomedical Research Centre, University of Leicester, Leicester, United Kingdom
| | - Mintu Nath
- Medical Statistics Team, Institute of Applied Health Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Ronney B Panerai
- Department of Cardiovascular Sciences, University of Leicester, LE1 5WW Leicester, United Kingdom; National Institutes for Health Research Leicester Biomedical Research Centre, University of Leicester, Leicester, United Kingdom
| | - Thompson G Robinson
- Department of Cardiovascular Sciences, University of Leicester, LE1 5WW Leicester, United Kingdom; National Institutes for Health Research Leicester Biomedical Research Centre, University of Leicester, Leicester, United Kingdom
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Neurovascular Coupling Impairment in Heart Failure with Reduction Ejection Fraction. Brain Sci 2020; 10:brainsci10100714. [PMID: 33036338 PMCID: PMC7601077 DOI: 10.3390/brainsci10100714] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 09/27/2020] [Accepted: 10/01/2020] [Indexed: 12/19/2022] Open
Abstract
The hemodynamic consequences of a persistent reduced ejection fraction and unknown cardiac output on the brain have not been thoroughly studied. We sought to explore the status of the mechanisms of cerebrovascular regulation in patients with heart failure with reduced (HFrEF) and recovered (HFrecEF) ejection fraction. We monitored cerebral blood flow velocity (CBFV) with transcranial Doppler and blood pressure. Cerebral autoregulation, assessed by transfer function from the spontaneous oscillations of blood pressure to CBFV and neurovascular coupling (NVC) with visual stimulation were compared between groups of HFrEF, HFrecEF and healthy controls. NVC was significantly impaired in HFrEF patients with reduced augmentation of CBFV during stimulation (overshoot systolic CBFV 19.11 ± 6.92 vs. 22.61 ± 7.78 vs. 27.92 ± 6.84, p = 0.04), slower upright of CBFV (rate time to overshoot: 1.19 ± 3.0 vs. 3.06 (4.30) vs. 2.90 ± 3.84, p = 0.02); p = 0.023) and reduced arterial oscillatory properties (natural frequency 0.17 ± 0.06 vs. 0.20 ± 0.09 vs. 0.24 ± 0.07, p = 0.03; attenuation 0.34 ± 0.24 vs. 0.48 ± 0.35 vs. 0.50 ± 0.23, p = 0.05). Cerebral autoregulation was preserved. The neurovascular unit of subjects with chronically reduced heart pumping capability is severely dysfunctional. Dynamic testing with transcranial Doppler could be useful in these patients, but whether it helps in predicting cognitive impairment must be addressed in future prospective studies.
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Lee YK, Rothwell PM, Payne SJ, Webb AJS. Reliability, reproducibility and validity of dynamic cerebral autoregulation in a large cohort with transient ischaemic attack or minor stroke. Physiol Meas 2020; 41:095002. [PMID: 32764198 PMCID: PMC7116588 DOI: 10.1088/1361-6579/abad49] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Objective Cerebral autoregulation (CA) is critical to maintenance of cerebral perfusion but its relevance to the risk of stroke and dementia has been under-studied due to small study sizes and a lack of consensus as to the optimal method of measurement. We determined the reliability and reproducibility of multiple CA indices and the effect of intensive data-processing in a large population with transient ischaemic attack or minor stroke. Approach Consecutive, consenting patients in the population-based OXVASC (Oxford Vascular Study) Phenotyped cohort underwent up to 10-min supine continuous blood pressure monitoring (Finometer) with bilateral middle cerebral artery (MCA) transcranial ultrasound (DWL-Dopplerbox). Un-processed waveforms (Un-A) were median-filtered, systematically reviewed, artefacts corrected and their quality blindly graded (optimal (A) to worst (E)). CA metrics were derived in time-domain (autoregulatory index (ARI), Pearson’s Mx, Sx, Dx) and in very-low (VLF) and low-frequency (LF) domains (WPS-SI: wavelet phase synchronisation, transfer function analysis), stratified by recording quality. Reliability and reproducibility (Cronbach’s Alpha) were determined comparing MCA sides and the first vs. second 5-min of monitoring. Main results In 453 patients, following manual data-cleaning, there was good reliability of indices when comparing MCA sides (Mx: 0.77; WPS-SI-VLF: 0.85; WPS-SI-LF 0.84), or repeated five minute epochs (Mx: 0.57; WPS-SI-VLF: 0.69; WPS-SI-LF 0.90), with persistently good reliability between sides even in lower quality Groups (Group D: Mx: 0.79; WPS-SI-VLF: 0.92; WPS-SI-LF: 0.91). Reliability was greatest for Pearson’s Mx and wavelet synchronisation index, with reasonable reliability of transfer function analyses, but ARI was prone to occasional, potentially defective, extreme estimates (Left vs right MCA: 0.68). Significance Resting-state measures of CA were valid, reproducible and robust to moderate noise, but require careful data-processing. Mx and wavelet synchronisation index were the most reliable indices for determining the prognostic value of CA in large epidemiological cohorts and its potential as a treatment target.
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Affiliation(s)
- Yun-Kai Lee
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Old Road Campus Research Building, Oxford, OX3 7DQ, United Kingdom
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Llwyd O, Haunton V, Salinet ASM, Nath M, Lam MY, Saeed NP, Brodie F, Robinson TG, Panerai RB. Can we assess dynamic cerebral autoregulation in stroke patients with high rates of cardiac ectopicity? Med Biol Eng Comput 2019; 57:2731-2739. [PMID: 31734767 DOI: 10.1007/s11517-019-02064-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 11/02/2019] [Indexed: 10/25/2022]
Abstract
It is unclear whether physiological recordings containing high numbers of ectopic heartbeats can be used to measure the cerebral autoregulation (CA) of blood flow. This study evaluated the utility of such data for assessing dynamic CA capacity. Physiological recordings of cerebral blood flow velocity, heart rate, end-tidal CO2 and beat-to-beat blood pressure from acute ischaemic stroke (AIS) patients (n = 46) containing ectopic heartbeats of varying number (0.2 to 25 occurrences per minute) were analysed. Dynamic CA was determined using the autoregulation index (ARI) and the normalised mean square error (NMSE) was used to evaluate the fitting of the step response between BP and CBFV to Tiecks' model. We fitted linear mixed models on the CA variables incorporating ectopic burden, age, sex and hemisphere as predictor variables. Ectopic activity demonstrated an association with mean coherence (p = 0.006) but not with ARI (p = 0.162), impaired CA based on dichotomised ARI (p = 0.859) or NMSE (p = 0.671). Dynamic CA could be reliably assessed in AIS patients using physiological recordings with high rates of cardiac ectopic activity. This provides supportive data for future studies evaluating CA capability in AIS patients, with the potential to develop more individualised treatment strategies. Graphical Abstract.
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Affiliation(s)
- Osian Llwyd
- Department of Cardiovascular Sciences, Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, University of Leicester, Room 225, Level 2, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, LE2 7LX, UK
| | - Victoria Haunton
- Department of Cardiovascular Sciences, Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, University of Leicester, Room 225, Level 2, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, LE2 7LX, UK.,NIHR Leicester Biomedical Research Centre, University of Leicester, Leicester, UK
| | - Angela S M Salinet
- Department of Cardiovascular Sciences, Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, University of Leicester, Room 225, Level 2, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, LE2 7LX, UK
| | - Mintu Nath
- Department of Cardiovascular Sciences, Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, University of Leicester, Room 225, Level 2, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, LE2 7LX, UK.,NIHR Leicester Biomedical Research Centre, University of Leicester, Leicester, UK
| | - Man Y Lam
- Department of Cardiovascular Sciences, Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, University of Leicester, Room 225, Level 2, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, LE2 7LX, UK
| | - Nazia P Saeed
- Department of Cardiovascular Sciences, Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, University of Leicester, Room 225, Level 2, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, LE2 7LX, UK
| | - Fiona Brodie
- Department of Cardiovascular Sciences, Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, University of Leicester, Room 225, Level 2, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, LE2 7LX, UK
| | - Thompson G Robinson
- Department of Cardiovascular Sciences, Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, University of Leicester, Room 225, Level 2, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, LE2 7LX, UK.,NIHR Leicester Biomedical Research Centre, University of Leicester, Leicester, UK
| | - Ronney B Panerai
- Department of Cardiovascular Sciences, Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, University of Leicester, Room 225, Level 2, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, LE2 7LX, UK. .,NIHR Leicester Biomedical Research Centre, University of Leicester, Leicester, UK.
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22
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Intharakham K, Beishon L, Panerai RB, Haunton VJ, Robinson TG. Assessment of cerebral autoregulation in stroke: A systematic review and meta-analysis of studies at rest. J Cereb Blood Flow Metab 2019; 39:2105-2116. [PMID: 31433714 PMCID: PMC6827119 DOI: 10.1177/0271678x19871013] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Dynamic cerebral autoregulation (dCA) has been shown to be impaired in cerebrovascular diseases, but there is a lack of consistency across different studies and the different metrics that have been proposed for assessment. We performed a systematic review and meta-analyses involving assessment of dCA in ischemic and hemorrhagic stroke. Thirty-three articles describing assessment of dCA with transfer function analysis (TFA) were included, with meta-analyses performed for derived parameters of gain, phase and autoregulation index (ARI). A total of 1233 patients were pooled from 12 studies on acute ischemic stroke (AIS) and two studies on intracerebral hemorrhage (ICH). In comparison with controls, TFA phase of AIS was significantly reduced (nine studies), in both hemispheres (P < 0.0001). TFA gain provided inconsistent results, with reduced values in relation to controls, for both hemispheres. The ARI (six studies) was reduced compared to controls, in both hemispheres (P < 0.005). In ICH, gain showed higher values compared to controls for the unaffected (P = 0.01), but not for the affected hemisphere. Meta-analyses in AIS have demonstrated that phase and the ARI index can show highly significant differences in comparison with healthy controls, while ICH have been limited by the scarcity of studies and the diversity of units adopted for gain.
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Affiliation(s)
| | - Lucy Beishon
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
| | - Ronney B Panerai
- 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
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK.,NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, UK
| | - Thompson G Robinson
- 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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23
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Guo ZN, Jin H, Sun H, Zhao Y, Liu J, Ma H, Sun X, Yang Y. Antioxidant Melatonin: Potential Functions in Improving Cerebral Autoregulation After Subarachnoid Hemorrhage. Front Physiol 2018; 9:1146. [PMID: 30174621 PMCID: PMC6108098 DOI: 10.3389/fphys.2018.01146] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Accepted: 07/30/2018] [Indexed: 12/30/2022] Open
Abstract
Subarachnoid hemorrhage (SAH) is a subtype of stroke with high mortality and morbidity. Impaired cerebral autoregulation following SAH has been reported owing to effects on sympathetic control, endothelial function, myogenic response, and cerebral metabolism. Impaired cerebral autoregulation is associated with early brain injury, cerebral vasospasm/delayed cerebral ischemia, and SAH prognosis. However, few drugs have been reported to improve cerebral autoregulation after SAH. Melatonin is a powerful antioxidant that is effective (easily crosses the blood brain barrier) and safe (tolerated in large doses without toxicity). Theoretically, melatonin may impact the control mechanisms of cerebral autoregulation via antioxidative effects, protection of endothelial cell integrity, suppression of sympathetic nerve activity, increase in nitric oxide bioavailability, mediation of the myogenic response, and amelioration of hypoxemia. Furthermore, melatonin may have a comprehensive effect on cerebral autoregulation. This review discusses the potential effects of melatonin on cerebral autoregulation following SAH, in terms of the association between pharmacological activities and the mechanisms of cerebral autoregulation.
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Affiliation(s)
- Zhen-Ni Guo
- Department of Neurology, The First Hospital of Jilin University, Changchun, China.,Clinical Trial and Research Center for Stroke, Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Hang Jin
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Huijie Sun
- Cadre Ward, The First Hospital of Jilin University, Changchun, China
| | - Yingkai Zhao
- Cadre Ward, The First Hospital of Jilin University, Changchun, China
| | - Jia Liu
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Hongyin Ma
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Xin Sun
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Yi Yang
- Department of Neurology, The First Hospital of Jilin University, Changchun, China.,Clinical Trial and Research Center for Stroke, Department of Neurology, The First Hospital of Jilin University, Changchun, China
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24
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Llwyd O, Salinet ASM, Panerai RB, Lam MY, Saeed NP, Brodie F, Bor-Seng-Shu E, Robinson TG, Nogueira RC. Cerebral Haemodynamics following Acute Ischaemic Stroke: Effects of Stroke Severity and Stroke Subtype. Cerebrovasc Dis Extra 2018; 8:80-89. [PMID: 29996123 PMCID: PMC6489023 DOI: 10.1159/000487514] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 02/07/2018] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Acute ischaemic stroke (AIS) patients often show impaired cerebral autoregulation (CA). We tested the hypothesis that CA impairment and other alterations in cerebral haemodynamics are associated with stroke subtype and severity. METHODS AIS patients (n = 143) were amalgamated from similar studies. Data from baseline (< 48 h stroke onset) physiological recordings (beat-to-beat blood pressure [BP], cerebral blood flow velocity (CBFV) from bilateral insonation of the middle cerebral arteries) were calculated for mean values and autoregulation index (ARI). Differences were assessed between stroke subtype (Oxfordshire Community Stroke Project [OCSP] classification) and severity (National Institutes of Health Stroke Scale [NIHSS] score < 5 and 5-25). Correlation coefficients assessed associations between NIHSS and physiological measurements. RESULTS Thirty-two percent of AIS patients had impaired CA (ARI < 4) in affected hemisphere (AH) that was similar between stroke subtypes and severity. CBFV in AH was comparable between stroke subtype and severity. In unaffected hemisphere (UH), differences existed in mean CBFV between lacunar and total anterior circulation OCSP subtypes (42 vs. 56 cm•s-1, p < 0.01), and mild and moderate-to-severe stroke severity (45 vs. 51 cm•s-1, p = 0.04). NIHSS was associated with peripheral (diastolic and mean arterial BP) and cerebral haemodynamic parameters (CBFV and ARI) in the UH. CONCLUSIONS AIS patients with different OCSP subtypes and severity have homogeneity in CA capability. Cerebral haemodynamic measurements in the UH were distinguishable between stroke subtype and severity, including the association between deteriorating ARI in UH with stroke severity. More studies are needed to determine their clinical significance and to understand the determinants of CA impairment in AIS patients.
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Affiliation(s)
- Osian Llwyd
- Department of Cardiovascular Sciences Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, University of Leicester, Leicester, United Kingdom
| | - Angela S M Salinet
- Department of Cardiovascular Sciences Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, University of Leicester, Leicester, United Kingdom.,Neurology Department, Hospital das Clinicas, School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Ronney B Panerai
- Department of Cardiovascular Sciences Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, University of Leicester, Leicester, United Kingdom
| | - Man Y Lam
- Department of Cardiovascular Sciences Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, University of Leicester, Leicester, United Kingdom
| | - Nazia P Saeed
- Department of Cardiovascular Sciences Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, University of Leicester, Leicester, United Kingdom
| | - Fiona Brodie
- Department of Cardiovascular Sciences Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, University of Leicester, Leicester, United Kingdom
| | - Edson Bor-Seng-Shu
- Neurology Department, Hospital das Clinicas, School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Thompson G Robinson
- Department of Cardiovascular Sciences Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, University of Leicester, Leicester, United Kingdom
| | - Ricardo C Nogueira
- Neurology Department, Hospital das Clinicas, School of Medicine, University of São Paulo, São Paulo, Brazil
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25
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McKetton L, Venkatraghavan L, Poublanc J, Sobczyk O, Crawley AP, Rosen C, Silver FL, Duffin J, Fisher JA, Mikulis DJ. Importance of Collateralization in Patients With Large Artery Intracranial Occlusive Disease: Long-Term Longitudinal Assessment of Cerebral Hemodynamic Function. Front Neurol 2018; 9:226. [PMID: 29681886 PMCID: PMC5897547 DOI: 10.3389/fneur.2018.00226] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Accepted: 03/23/2018] [Indexed: 01/14/2023] Open
Abstract
Patients with large artery intracranial occlusive disease (LAICOD) are at risk for both acute ischemia and chronic hypoperfusion. Collateral circulation plays an important role in prognosis, and imaging plays an essential role in diagnosis, treatment planning, and prognosis of patients with LAICOD. In addition to standard structural imaging, assessment of cerebral hemodynamic function is important to determine the adequacy of collateral supply. Among the currently available methods of assessment of cerebral hemodynamic function, measurement of cerebrovascular reactivity (CVR) using blood oxygen level-dependent (BOLD) MRI and precisely controlled CO2 has shown to be a safe, reliable, reproducible, and clinically useful method for long-term assessment of patients. Here, we report a case of long-term follow-up in a 28-year-old Caucasian female presented to the neurology clinic with a history of TIAs and LAICOD of the right middle cerebral artery (MCA). Initial structural MRI showed a right MCA stenosis and a small right coronal radiate lacunar infarct. Her CVR study showed a large area of impaired CVR with a paradoxical decrease in BOLD signal with hypercapnia involving the right MCA territory indicating intracerebral steal. The patient was managed medically with anticoagulant and antiplatelet therapy and was followed-up for over 9 years with both structural and functional imaging. Cortical thickness (CT) measures were longitudinally assessed from a region of interest that was applied to subsequent time points in the cortical region exhibiting steal physiology and in the same region of the contralateral healthy hemisphere. In the long-term follow-up, the patient exhibited improvement in her CVR as demonstrated by the development of collaterals with negligible changes to CT. Management of patients with LAICOD remains challenging since no revascularization strategies have shown efficacy except in patients with moyamoya disease. Management is well defined for acute ischemia where the presence and the adequacy of the collateralization dictate the need for intervention. Long-term assessment in neurovascular uncoupling (i.e., chronic ischemia) may reveal improvements in CVR as the durability of compensatory collaterals improve, even in cases with no intervention. Thus, assessment of cerebrovascular hemodynamics using CVR measurements coupled with time-of-flight MR angiography can be useful in the clinical management of patients with LAICOD.
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Affiliation(s)
- Larissa McKetton
- Division of Neuroradiology, Joint Department of Medical Imaging, University Health Network, Toronto, ON, Canada
| | | | - Julien Poublanc
- Division of Neuroradiology, Joint Department of Medical Imaging, University Health Network, Toronto, ON, Canada
| | - Olivia Sobczyk
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Adrian P Crawley
- Division of Neuroradiology, Joint Department of Medical Imaging, University Health Network, Toronto, ON, Canada.,Institute of Medical Science, University of Toronto, Toronto, ON, Canada.,Department of Medical Imaging, University of Toronto, Toronto, ON, Canada
| | - Casey Rosen
- Division of Neuroradiology, Joint Department of Medical Imaging, University Health Network, Toronto, ON, Canada
| | - Frank L Silver
- Division of Neurology, Department of Medicine, University of Toronto, Toronto, ON, Canada
| | - James Duffin
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Joseph A Fisher
- Division of Neuroradiology, Joint Department of Medical Imaging, University Health Network, Toronto, ON, Canada.,Department of Anaesthesia, University Health Network, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - David J Mikulis
- Division of Neuroradiology, Joint Department of Medical Imaging, University Health Network, Toronto, ON, Canada.,Institute of Medical Science, University of Toronto, Toronto, ON, Canada.,Department of Medical Imaging, University of Toronto, Toronto, ON, Canada
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26
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Patel N, Panerai RB, Haunton V, Katsogridakis E, Saeed NP, Salinet A, Brodie F, Syed N, D'Sa S, Robinson TG. The Leicester cerebral haemodynamics database: normative values and the influence of age and sex. Physiol Meas 2016; 37:1485-98. [PMID: 27511128 DOI: 10.1088/0967-3334/37/9/1485] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Normative values of physiological parameters hold significance in modern day clinical decision-making. Lack of such normative values has been a major hurdle in the translation of research into clinical practice. A large database containing uniform recordings was constructed to allow more robust estimates of normative ranges and also assess the influence of age and sex. Doppler recordings were performed on healthy volunteers in the same laboratory, using similar protocols and equipment. Beat-to-beat blood pressure, heart-rate, electrocardiogram, and end-tidal CO2 were measured continuously. Bilateral insonation of the middle cerebral arteries (MCAs) was performed using TCD following a 15 min stabilisation, and a 5 min baseline recording. Good quality Doppler recordings for both MCAs were obtained in 129 participants (57 female) with a median age of 57 years (range 20-82). Age was found to influence baseline haemodynamic and transfer function analysis parameters. Cerebral blood flow velocity and critical closing pressure were the only sex-related differences found, which was significantly higher in females than males. Normative values for cerebral haemodynamic parameters have been defined in a large, healthy population. Such age/sex-defined normal values can be used to reduce the burden of collecting additional control data in future studies, as well as to identify disease-associated changes.
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Affiliation(s)
- Nikil Patel
- Department of Cardiovascular Sciences, Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, University of Leicester, Leicester, LE2 7LX, UK. NIHR Biomedical Research Unit for Cardiovascular Sciences, University of Leicester, Leicester, UK
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27
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Hilz MJ, Wang R, Marthol H, Liu M, Tillmann A, Riss S, Hauck P, Hösl KM, Wasmeier G, Stemper B, Köhrmann M. Partial pharmacologic blockade shows sympathetic connection between blood pressure and cerebral blood flow velocity fluctuations. J Neurol Sci 2016; 365:181-7. [PMID: 27206903 DOI: 10.1016/j.jns.2016.04.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 03/24/2016] [Accepted: 04/07/2016] [Indexed: 11/18/2022]
Abstract
Cerebral autoregulation (CA) dampens transfer of blood pressure (BP)-fluctuations onto cerebral blood flow velocity (CBFV). Thus, CBFV-oscillations precede BP-oscillations. The phase angle (PA) between sympathetically mediated low-frequency (LF: 0.03-0.15Hz) BP- and CBFV-oscillations is a measure of CA quality. To evaluate whether PA depends on sympathetic modulation, we assessed PA-changes upon sympathetic stimulation with and without pharmacologic sympathetic blockade. In 10 healthy, young men, we monitored mean BP and CBFV before and during 120-second cold pressor stimulation (CPS) of one foot (0°C ice-water). We calculated mean values, standard deviations and sympathetic LF-powers of all signals, and PAs between LF-BP- and LF-CBFV-oscillations. We repeated measurements after ingestion of the adrenoceptor-blocker carvedilol (25mg). We compared parameters before and during CPS, without and after carvedilol (analysis of variance, post-hoc t-tests, significance: p<0.05). Without carvedilol, CPS increased BP, CBFV, BP-LF- and CBFV-LF-powers, and shortened PA. Carvedilol decreased resting BP, CBFV, BP-LF- and CBFV-LF-powers, while PAs remained unchanged. During CPS, BPs, CBFVs, BP-LF- and CBFV-LF-powers were lower, while PAs were longer with than without carvedilol. With carvedilol, CPS no longer shortened resting PA. Sympathetic activation shortens PA. Partial adrenoceptor blockade abolishes this PA-shortening. Thus, PA-measurements provide a subtle marker of sympathetic influences on CA and might refine CA evaluation.
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Affiliation(s)
- Max J Hilz
- Department of Neurology, University of Erlangen-Nuremberg, Schwabachanlage 6, D-91054 Erlangen, Germany.
| | - Ruihao Wang
- Department of Neurology, University of Erlangen-Nuremberg, Schwabachanlage 6, D-91054 Erlangen, Germany.
| | - Harald Marthol
- Department of Psychiatry, Addiction, Psychotherapy and Psychosomatics, Klinikum am Europakanal, Am Europakanal 71, 91056 Erlangen, Germany.
| | - Mao Liu
- Department of Neurology, University of Erlangen-Nuremberg, Schwabachanlage 6, D-91054 Erlangen, Germany.
| | - Alexandra Tillmann
- Department of Neurology, University of Erlangen-Nuremberg, Schwabachanlage 6, D-91054 Erlangen, Germany.
| | - Stephan Riss
- Department of Neurology, University of Erlangen-Nuremberg, Schwabachanlage 6, D-91054 Erlangen, Germany.
| | - Paulina Hauck
- Department of Neurology, University of Erlangen-Nuremberg, Schwabachanlage 6, D-91054 Erlangen, Germany.
| | - Katharina M Hösl
- Department of Psychiatry and Psychotherapy, Paracelsus Medical University Nuremberg, Prof.-Ernst-Nathan-Strasse 1, 90419 Nuremberg, Germany.
| | - Gerald Wasmeier
- Department of Cardiology, Klinik Neustadt a. d. Aisch, Paracelsusstraße 30-36, 91413 Neustadt a. d. Aisch, Germany.
| | - Brigitte Stemper
- Department of Neurology, University of Erlangen-Nuremberg, Schwabachanlage 6, D-91054 Erlangen, Germany; Bayer HealthCare, Bayer Pharma AG, Global Development Specialty Medicine, Müllerstr. 178, Building P300, Room 239, 13353 Berlin, Germany.
| | - Martin Köhrmann
- Department of Neurology, University of Erlangen-Nuremberg, Schwabachanlage 6, D-91054 Erlangen, Germany.
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28
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Minhas JS, Syed NF, Haunton VJ, Panerai RB, Robinson TG, Mistri AK. Is dynamic cerebral autoregulation measurement using transcranial Doppler ultrasound reproducible in the presence of high concentration oxygen and carbon dioxide? Physiol Meas 2016; 37:673-82. [PMID: 27093290 DOI: 10.1088/0967-3334/37/5/673] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Reliability of cerebral blood flow velocity (CBFV) and dynamic cerebral autoregulation estimates (expressed as autoregulation index: ARI) using spontaneous fluctuations in blood pressure (BP) has been demonstrated. However, reliability during co-administration of O2 and CO2 is unknown. Bilateral CBFV (using transcranial Doppler), BP and RR interval recordings were performed in healthy volunteers (seven males, four females, age: 54 ± 10 years) on two occasions over 9 ± 4 d. Four 5 min recordings were made whilst breathing air (A), then 5%CO2 (C), 80%O2 (O) and mixed O2 + CO2 (M), in random order. CBFV was recorded; ARI was calculated using transfer function analysis. Precision was quantified as within-visit standard error of measurement (SEM) and the coefficient of variation (CV). CBFV and ARI estimates with A (SEM: 3.85 & 0.87; CV: 7.5% & 17.8%, respectively) were comparable to a previous reproducibility study. The SEM and CV with C and O were similar, though higher values were noted with M; Bland-Altman plots indicated no significant bias across all gases for CBFV and ARI (bias <0.06 cm s(-1) and <0.05, respectively). Thus, transcranial-Doppler-ultrasound-estimated CBFV and ARI during inhalation of O2 and CO2 have acceptable levels of reproducibility and can be used to study the effect of these gases on cerebral haemodynamics.
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Affiliation(s)
- Jatinder S Minhas
- Ageing and Stroke Medicine, Department of Cardiovascular Sciences, University of Leicester, Stroke Research Office, Victoria Building, Leicester Royal Infirmary, Leicester LE1 5WW, UK. NIHR Leicester Cardiovascular Biomedical Research Unit, University of Leicester, Leicester, UK. Department of Stroke Medicine, University Hospitals of Leicester NHS Trust, Leicester, UK
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29
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Wang S, Guo ZN, Xing Y, Ma H, Jin H, Liu J, Yang Y. Dynamic Cerebral Autoregulation in Asymptomatic Patients With Unilateral Middle Cerebral Artery Stenosis. Medicine (Baltimore) 2015; 94:e2234. [PMID: 26717363 PMCID: PMC5291604 DOI: 10.1097/md.0000000000002234] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The aim of the study was to assess the capacity of dynamic cerebral autoregulation (dCA) in asymptomatic patients with unilateral middle cerebral artery (MCA) stenosis.Fifty-seven patients with asymptomatic mild, moderate, and severe unilateral MCA stenosis and 8 patients with symptomatic severe unilateral MCA stenosis diagnosed by transcranial Doppler were enrolled. Twenty-four healthy volunteers served as controls. The noninvasive continuous cerebral blood flow velocity and arterial blood pressure were recorded simultaneously from each subject in the supine position. Transfer function analysis was applied to determine the autoregulatory parameters (phase difference [PD] and gain).The PD values in the severe stenosis groups were significantly lower than those of the control group (60.71 ± 18.63°), the asymptomatic severe stenosis group was impaired ipsilaterally (28.94 ± 27.43°, P < 0.001), and the symptomatic severe stenosis group was impaired bilaterally (13.74 ± 19.21°, P < 0.001; 19.68 ± 14.50°, P = 0.006, respectively). The PD values in the mild and moderate stenosis groups were not significantly different than the controls (44.49 ± 27.93°; 48.65 ± 25.49°, respectively). The gain values in the mild and moderate groups were higher than in the controls (1.00 ± 0.58 cm/s/mm Hg vs 0.86 ± 0.34 cm/s/mm Hg, and 1.20 ± 0.59 cm/s/mm Hg vs 0.86 ± 0.34 cm/s/mm Hg, respectively). The gain values in the severe stenosis groups were significantly lower than that in the control group: the asymptomatic severe stenosis group was lower bilaterally (0.56 ± 0.32 cm/s/mm Hg, P = 0.003; 0.60 ± 0.32 cm/s/mm Hg, P < 0.05, respectively), whereas the symptomatic severe group was lower unilaterally (on the contralateral side) (0.53 ± 0.43 cm/s/mm Hg, P < 0.05).In asymptomatic patients with unilateral MCA stenosis, only the dCA of the severe stenosis was ipsilaterally impaired. Acute stroke may aggravate the impaired dCA and even spread contralaterally.
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Affiliation(s)
- Shuang Wang
- From the Stroke Center, Department of Neurology (SW, HM, HJ, YY); Neuroscience Center, Department of Neurology (Z-NG); Center for Neurovascular ultrasound (Y X), the First Hospital of Jilin Universit, Changchun, China and Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Xueyuan Avenue, Shenzhen University Town, Shenzhen, China (JL)
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30
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Seo HJ, Pagsisihan JR, Paeng JC, Choi SH, Cheon GJ, Chung JK, Lee DS, Kang KW. Hemodynamic Significance of Internal Carotid or Middle Cerebral Artery Stenosis Detected on Magnetic Resonance Angiography. Yonsei Med J 2015; 56:1686-93. [PMID: 26446655 PMCID: PMC4630061 DOI: 10.3349/ymj.2015.56.6.1686] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 01/12/2015] [Accepted: 02/03/2015] [Indexed: 12/04/2022] Open
Abstract
PURPOSE We evaluated hemodynamic significance of stenosis on magnetic resonance angiography (MRA) using acetazolamide perfusion single photon emission computed tomography (SPECT). MATERIALS AND METHODS Of 171 patients, stenosis in internal carotid artery (ICA) and middle cerebral artery (MCA) (ICA-MCA) on MRA and cerebrovascular reserve (CVR) of MCA territory on SPECT was measured using quantification and a 3-grade system. Stenosis and CVR grades were compared with each other, and their prognostic value for subsequent stroke was evaluated. RESULTS Of 342 ICA-MCA, 151 (44%) presented stenosis on MRA; grade 1 in 69 (20%) and grade 2 in 82 (24%) cases. Decreased CVR was observed in 9% of grade 0 stenosis, 25% of grade 1, and 35% of grade 2. The average CVR of grade 0 was significantly different from grade 1 (p<0.001) and grade 2 stenosis (p=0.007). In quantitative analysis, average CVR index was -0.56±7.91 in grade 0, -1.81±6.66 in grade 1 and -1.18±5.88 in grade 2 stenosis. Agreement between stenosis and CVR grades was fair in patients with lateralizing and non-lateralizing symptoms (κ=0.230 and 0.346). Of the factors tested, both MRA and CVR were not significant prognostic factors (p=0.104 and 0.988, respectively), whereas hypertension and renal disease were significant factors (p<0.05, respectively). CONCLUSION A considerable proportion of ICA-MCA stenosis detected on MRA does not cause CVR impairment despite a fair correlation between them. Thus, hemodynamic state needs to be assessed for evaluating significance of stenosis, particularly in asymptomatic patients.
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Affiliation(s)
- Hyo Jung Seo
- Department of Nuclear Medicine, Seoul National University Hospital, Seoul, Korea
- Department of Molecular Medicine and Biopharmaceutical Sciences, WCU Graduate School of Convergence Science and Technology, Seoul National University College of Medicine, Seoul, Korea
- Department of Nuclear Medicine, Korea University College of Medicine, Seoul, Korea
| | | | - Jin Chul Paeng
- Department of Nuclear Medicine, Seoul National University Hospital, Seoul, Korea.
| | - Seung Hong Choi
- Department of Radiology, Seoul National University Hospital, Seoul, Korea
| | - Gi Jeong Cheon
- Department of Nuclear Medicine, Seoul National University Hospital, Seoul, Korea
| | - June-Key Chung
- Department of Nuclear Medicine, Seoul National University Hospital, Seoul, Korea
| | - Dong Soo Lee
- Department of Nuclear Medicine, Seoul National University Hospital, Seoul, Korea
- Department of Molecular Medicine and Biopharmaceutical Sciences, WCU Graduate School of Convergence Science and Technology, Seoul National University College of Medicine, Seoul, Korea
| | - Keon Wook Kang
- Department of Nuclear Medicine, Seoul National University Hospital, Seoul, Korea
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31
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Panunzi S, D’Orsi L, Iacoviello D, De Gaetano A. A stochastic delay differential model of cerebral autoregulation. PLoS One 2015; 10:e0118456. [PMID: 25830915 PMCID: PMC4382334 DOI: 10.1371/journal.pone.0118456] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 01/16/2015] [Indexed: 01/09/2023] Open
Abstract
Mathematical models of the cardiovascular system and of cerebral autoregulation (CAR) have been employed for several years in order to describe the time course of pressures and flows changes subsequent to postural changes. The assessment of the degree of efficiency of cerebral auto regulation has indeed importance in the prognosis of such conditions as cerebro-vascular accidents or Alzheimer. In the quest for a simple but realistic mathematical description of cardiovascular control, which may be fitted onto non-invasive experimental observations after postural changes, the present work proposes a first version of an empirical Stochastic Delay Differential Equations (SDDEs) model. The model consists of a total of four SDDEs and two ancillary algebraic equations, incorporates four distinct delayed controls from the brain onto different components of the circulation, and is able to accurately capture the time course of mean arterial pressure and cerebral blood flow velocity signals, reproducing observed auto-correlated error around the expected drift.
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Affiliation(s)
- Simona Panunzi
- Consiglio Nazionale delle Ricerche, Istituto di Analisi dei Sistemi ed Informatica “Antonio Ruberti”, Rome, Italy
| | - Laura D’Orsi
- Consiglio Nazionale delle Ricerche, Istituto di Analisi dei Sistemi ed Informatica “Antonio Ruberti”, Rome, Italy
- * E-mail:
| | - Daniela Iacoviello
- Dipartimento di Ingegneria Informatica, Automatica e Gestionale “Antonio Ruberti”, Rome, Italy
| | - Andrea De Gaetano
- Consiglio Nazionale delle Ricerche, Istituto di Analisi dei Sistemi ed Informatica “Antonio Ruberti”, Rome, Italy
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32
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Rucka D, Marek J, Rucklova Z, Lubanda JC, Havranek S, Skvaril J, Varejka P, Chochola M, Karetova D, Korinek J, Linhart A. Arterial stiffening contributes to impairment of cerebrovascular reactivity in patients with coronary artery disease without carotid stenosis. Physiol Res 2014; 64:335-43. [PMID: 25536320 DOI: 10.33549/physiolres.932837] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Impaired cerebrovascular reactivity (CVR), an important risk factor for future stroke, is affected by a presence carotid stenosis. However, in some cases CVR can be impaired in the absence of carotid stenosis due to several poorly characterized mechanisms. We hypothesized that arterial stiffening as observed in coronary heart disease (CHD) could be associated with alteration in CVR in CHD patients without carotid stenosis. The study population consisted of patients referred for coronary angiography without significant carotid stenosis (<50 %). CVR was evaluated by breath holding index (BHI) measured with transcranial color code duplex ultrasound. Arterial stiffness was assessed by pulse wave velocity (PWV) measured by the oscillometric method. The extent of coronary atherosclerosis was quantified by Gensini score (GS). Out of 186 subjects, sixty-two patients fulfilled the inclusion and exclusion criteria. BHI decreased with increasing PWV (r = -0.47, p<0.001). Decrease in BHI was significantly inversely associated with GS (r = -0.61, p<0.001). GS was associated with PWV (p<0.001). In conclusion, impaired CVR was associated with increased arterial stiffening in CHD patients in the absence of significant carotid stenosis. Thus, we speculate that increased arterial stiffness may at least partially contribute to the pathophysiology of CVR alteration in coronary artery disease.
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Affiliation(s)
- D Rucka
- Second Department of Internal Medicine - Cardiology and Angiology, General University Hospital, First School of Medicine, Charles University, Prague, Czech Republic.
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