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Peng Q, Liu X, Ai M, Huang L, Li L, Liu W, Zhao C, Hu C, Zhang L. Cerebral autoregulation-directed optimal blood pressure management reduced the risk of delirium in patients with septic shock. JOURNAL OF INTENSIVE MEDICINE 2024; 4:376-383. [PMID: 39035614 PMCID: PMC11258506 DOI: 10.1016/j.jointm.2023.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 12/05/2023] [Accepted: 12/08/2023] [Indexed: 07/23/2024]
Abstract
Background When resuscitating patients with septic shock, cerebrovascular reactivity parameters are calculated by monitoring regional cerebral oxygen saturation (rSO2) using near-infrared spectroscopy to determine the optimal blood pressure. Here, we aimed to analyze the impact of cerebral autoregulation-directed optimal blood pressure management on the incidence of delirium and the prognosis of patients with septic shock. Methods This prospective randomized controlled clinical study was conducted in the Xiangya Hospital of Central South University, China. Fifty-one patients with septic shock (December 2020-May 2022) were enrolled and randomly allocated to the experimental (n=26) or control group (n=25). Using the ICM+ software, we monitored the dynamic changes in rSO2 and mean arterial pressure (MAP) and calculated the cerebrovascular reactivity parameter tissue oxygen reactivity index to determine the optimal blood pressure to maintain normal cerebral autoregulation function during resuscitation in the experimental group. The control group was treated according to the Surviving Sepsis Campaign Guidelines. Differences in the incidence of delirium and 28-day mortality between the two groups were compared, and the risk factors were analyzed. Results The 51 patients, including 39 male and 12 female, had a mean age of (57.0±14.9) years. The incidence of delirium was 40.1% (23/51), and the 28-day mortality rate was 29.4% (15/51). The mean MAP during the first 24 h of intensive care unit (ICU) admission was higher ([84.5±12.2] mmHg vs. [77.4±11.8] mmHg, P=0.040), and the incidence of delirium was lower (30.8% vs. 60.0%, P=0.036) in the experimental group than in the control group. The use of cerebral autoregulation-directed optimal blood pressure (odds ratio [OR]=0.090, 95% confidence interval [CI]: 0.009 to 0.923, P=0.043) and length of ICU stay (OR=1.473, 95% CI: 1.093 to 1.985, P=0.011) were risk factors for delirium during septic shock. Vasoactive drug dose (OR=8.445, 95% CI: 1.26 to 56.576, P=0.028) and partial pressure of oxygen (PaO2) (OR=0.958, 95% CI: 0.921 to 0.996, P=0.032) were the risk factors for 28-day mortality. Conclusions The use of cerebral autoregulation-directed optimal blood pressure management during shock resuscitation reduces the incidence of delirium in patients with septic shock. Trial Registration ClinicalTrials.gov ldentifer: NCT03879317.
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Affiliation(s)
- Qianyi Peng
- Department of Critical Care Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China
- Hunan Provincial Clinical Research Center for Critical Care Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Xia Liu
- Department of Critical Care Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China
- Hunan Provincial Clinical Research Center for Critical Care Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Meilin Ai
- Department of Critical Care Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China
- Hunan Provincial Clinical Research Center for Critical Care Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Li Huang
- Department of Critical Care Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China
- Hunan Provincial Clinical Research Center for Critical Care Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Li Li
- Department of Critical Care Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China
- Hunan Provincial Clinical Research Center for Critical Care Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Wei Liu
- Department of Critical Care Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China
- Hunan Provincial Clinical Research Center for Critical Care Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Chunguang Zhao
- Department of Critical Care Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China
- Hunan Provincial Clinical Research Center for Critical Care Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Chenghuan Hu
- Department of Critical Care Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China
- Hunan Provincial Clinical Research Center for Critical Care Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Lina Zhang
- Department of Critical Care Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China
- Hunan Provincial Clinical Research Center for Critical Care Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
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Olsen MH, Riberholt CG, Berg RMG, Møller K. Myths and methodologies: Assessment of dynamic cerebral autoregulation by the mean flow index. Exp Physiol 2024; 109:614-623. [PMID: 38376110 PMCID: PMC10988760 DOI: 10.1113/ep091327] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 01/17/2024] [Indexed: 02/21/2024]
Abstract
The mean flow index-usually referred to as Mx-has been used for assessing dynamic cerebral autoregulation (dCA) for almost 30 years. However, concerns have arisen regarding methodological consistency, construct and criterion validity, and test-retest reliability. Methodological nuances, such as choice of input (cerebral perfusion pressure, invasive or non-invasive arterial pressure), pre-processing approach and artefact handling, significantly influence mean flow index values, and previous studies correlating mean flow index with other established dCA metrics are confounded by inherent methodological flaws like heteroscedasticity, while the mean flow index also fails to discriminate individuals with presumed intact versus impaired dCA (discriminatory validity), and its prognostic performance (predictive validity) across various conditions remains inconsistent. The test-retest reliability, both within and between days, is generally poor. At present, no single approach for data collection or pre-processing has proven superior for obtaining the mean flow index, and caution is advised in the further use of mean flow index-based measures for assessing dCA, as current evidence does not support their clinical application.
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Affiliation(s)
- Markus Harboe Olsen
- Department of Neuroanaesthesiology, The Neuroscience CentreCopenhagen University Hospital − RigshospitaletCopenhagenDenmark
| | - Christian Gunge Riberholt
- Department of Neuroanaesthesiology, The Neuroscience CentreCopenhagen University Hospital − RigshospitaletCopenhagenDenmark
- Department of Brain and Spinal Cord Injury, The Neuroscience CentreCopenhagen University Hospital − RigshospitaletCopenhagenDenmark
| | - Ronan M. G. Berg
- Department of Clinical Physiology and Nuclear MedicineCopenhagen University Hospital − RigshospitaletCopenhagenDenmark
- Centre for Physical Activity ResearchCopenhagen University Hospital − RigshospitaletCopenhagenDenmark
- Department of Biomedical Sciences, Faculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
- Neurovascular Research Laboratory, Faculty of Life Sciences and EducationUniversity of South WalesPontypriddUK
| | - Kirsten Møller
- Department of Neuroanaesthesiology, The Neuroscience CentreCopenhagen University Hospital − RigshospitaletCopenhagenDenmark
- Department of Clinical Medicine, Faculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
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Shen ZD, Qu Y, Zhang P, Wang G, Wang Y, Yang Y, Xu B, Guo ZN. Dynamic Cerebral Autoregulation After Carotid Endarterectomy. J Endovasc Ther 2023:15266028231213608. [PMID: 38014769 DOI: 10.1177/15266028231213608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
OBJECTIVE Studies have shown that dynamic cerebral autoregulation (dCA) is impaired in patients with severe internal carotid artery (ICA) stenosis and that carotid endarterectomy (CEA) may improve dCA in these patients. However, the time course of dCA changes in patients after CEA remains unclear. Therefore, this study aimed to investigate the effects of CEA on the dCA in patients with carotid artery stenosis at different time points. METHODS This prospective study enrolled 44 patients (19 symptomatic stenosis patients and 25 asymptomatic stenosis patients) who underwent CEA and 44 age- and sex-matched controls. In the CEA group, the patients underwent dCA measurements at baseline, within 3 days, and 1 month after CEA. Transfer function parameters, phase difference (PD), and gain were used to quantify dCA. Changes in dCA before and after CEA were analyzed in detail. RESULTS The bilateral PD of the patients before CEA was significantly lower than that of the control group. This damage did not improve within 3 days after surgery. One month after surgery, the PD on the affected side of the patients significantly improved compared with before surgery and reached the level of the control group. The PD of affected side across time points in symptomatic and asymptomatic stenosis patients is consistent with that in all patients. CONCLUSIONS The dCA level did not improve immediately after CEA but significantly improved 1 month after surgery. This suggests that the occurrence of stroke should be considered in the acute period after CEA surgery, and its preventive effect on stroke may be effective after 1 month. CLINICAL IMPACT We found the dCA level did not improve immediately after CEA but significantly improved 1 month after surgury. This suggests that the occuttencce of stroke and surgical complications (such as cerebral hyperperfusion syndrome) associated with impaired dCA in the acute phase after CEA surgery should be of particular concern.
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Affiliation(s)
- Zi-Duo Shen
- Stroke Center, Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Yang Qu
- Stroke Center, Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Peng Zhang
- Neuroscience Research Center, Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Guibin Wang
- Stroke Center, Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - You Wang
- Stroke Center, Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Yi Yang
- Stroke Center, Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Baofeng Xu
- Stroke Center, Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Zhen-Ni Guo
- Stroke Center, Department of Neurology, The First Hospital of Jilin University, Changchun, China
- Neuroscience Research Center, Department of Neurology, The First Hospital of Jilin University, Changchun, China
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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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Sainbhi AS, Marquez I, Gomez A, Stein KY, Amenta F, Vakitbilir N, Froese L, Zeiler FA. Regional disparity in continuously measured time-domain cerebrovascular reactivity indices: a scoping review of human literature. Physiol Meas 2023; 44:07TR02. [PMID: 37336236 DOI: 10.1088/1361-6579/acdfb6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 06/19/2023] [Indexed: 06/21/2023]
Abstract
Objective: Cerebral blood vessels maintaining relatively constant cerebral blood flow (CBF) over wide range of systemic arterial blood pressure (ABP) is referred to as cerebral autoregulation (CA). Impairments in CA expose the brain to pressure-passive flow states leading to hypoperfusion and hyperperfusion. Cerebrovascular reactivity (CVR) metrics refer to surrogate metrics of pressure-based CA that evaluate the relationship between slow vasogenic fluctuations in cerebral perfusion pressure/ABP and a surrogate for pulsatile CBF/cerebral blood volume.Approach: We performed a systematically conducted scoping review of all available human literature examining the association between continuous CVR between more than one brain region/channel using the same CVR index.Main Results: In all the included 22 articles, only handful of transcranial doppler (TCD) and near-infrared spectroscopy (NIRS) based metrics were calculated for only two brain regions/channels. These metrics found no difference between left and right sides in healthy volunteer, cardiac surgery, and intracranial hemorrhage patient studies. In contrast, significant differences were reported in endarterectomy, and subarachnoid hemorrhage studies, while varying results were found regarding regional disparity in stroke, traumatic brain injury, and multiple population studies.Significance: Further research is required to evaluate regional disparity using NIRS-based indices and to understand if NIRS-based indices provide better regional disparity information than TCD-based indices.
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Affiliation(s)
- Amanjyot Singh Sainbhi
- Department of Biomedical Engineering, Price Faculty of Engineering, University of Manitoba, Winnipeg, Canada
| | - Izabella Marquez
- Undergraduate Engineering, Price Faculty of Engineering, University of Manitoba, Winnipeg, Canada
| | - Alwyn Gomez
- Section of Neurosurgery, Department of Surgery, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Canada
- Department of Human Anatomy and Cell Science, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Canada
| | - Kevin Y Stein
- Department of Biomedical Engineering, Price Faculty of Engineering, University of Manitoba, Winnipeg, Canada
| | - Fiorella Amenta
- Undergraduate Engineering, Price Faculty of Engineering, University of Manitoba, Winnipeg, Canada
| | - Nuray Vakitbilir
- Department of Biomedical Engineering, Price Faculty of Engineering, University of Manitoba, Winnipeg, Canada
| | - Logan Froese
- Department of Biomedical Engineering, Price Faculty of Engineering, University of Manitoba, Winnipeg, Canada
| | - Frederick A Zeiler
- Department of Biomedical Engineering, Price Faculty of Engineering, University of Manitoba, Winnipeg, Canada
- Section of Neurosurgery, Department of Surgery, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Canada
- Department of Human Anatomy and Cell Science, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Canada
- Centre on Aging, University of Manitoba, Winnipeg, Canada
- Division of Anaesthesia, Department of Medicine, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom
- Department of Clinical Neurosciences, Karolinksa Institutet, Stockholm, Sweden
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Semenyutin V, Antonov V, Malykhina G, Salnikov V. Investigation of Cerebral Autoregulation Using Time-Frequency Transformations. Biomedicines 2022; 10:biomedicines10123057. [PMID: 36551813 PMCID: PMC9775421 DOI: 10.3390/biomedicines10123057] [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: 09/04/2022] [Revised: 10/24/2022] [Accepted: 11/20/2022] [Indexed: 11/29/2022] Open
Abstract
The authors carried out the study of the state of systemic and cerebral hemodynamics in normal conditions and in various neurosurgical pathologies using modern signal processing methods. The results characterize the condition for the mechanisms of cerebral circulation Institute of Computer Science and Control, Higher School of Cyber-Physical Systems and Control regulation, which allows for finding a solution to fundamental and specific clinical problems for the effective treatment of patients with various pathologies. The proposed method is based on the continuous wavelet transform of systemic arterial pressure and blood flow velocity signals in the middle cerebral artery recorded by non-invasive methods of photoplethysmography and transcranial doppler ultrasonography. The study of these signals in real-time in the frequency range of Mayer waves makes it possible to determine the cerebral autoregulation state in certain diseases before and after surgical interventions. The proposed method uses a cross-wavelet spectrum, which helps obtain wavelet coherence and a phase shift between the wavelet coefficients of systemic arterial pressure signals and blood flow velocity in the Mayer wave range. The obtained results enable comparing the proposed method with that based on the short-time Fourier transform. The comparison showed that the proposed method has higher sensitivity to changes in cerebral autoregulation and better localization of changes in time and frequency.
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Affiliation(s)
- Vladimir Semenyutin
- Almazov National Medical Research Center, Ministry of Health of Russia, Polenov Neurosurgical Research Institute, 12 Mayakovsky Street, Saint-Petersburg 191014, Russia
| | - Valery Antonov
- Department of Higher Mathematics, Peter the Great St. Petersburg Polytechnic University, Saint-Petersburg 195251, Russia
| | - Galina Malykhina
- Higher School of Cyber-Physical Systems and Control, Institute of Computer Science and Control, Peter the Great St. Petersburg Polytechnic University, Saint-Petersburg 195251, Russia
- Correspondence: ; Tel.: +8-921-43-15-114
| | - Vyacheslav Salnikov
- Higher School of Cyber-Physical Systems and Control, Institute of Computer Science and Control, Peter the Great St. Petersburg Polytechnic University, Saint-Petersburg 195251, Russia
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Xiong L, Chen X, Liu J, Wong LKS, Leung TW. Cerebral Augmentation Effect Induced by External Counterpulsation Is Not Related to Impaired Dynamic Cerebral Autoregulation in Ischemic Stroke. Front Neurol 2022; 13:784836. [PMID: 35592467 PMCID: PMC9110640 DOI: 10.3389/fneur.2022.784836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 03/28/2022] [Indexed: 11/13/2022] Open
Abstract
Background and Purpose Dynamic cerebral autoregulation is impaired after ischemic stroke. External counterpulsation (ECP) augments the cerebral blood flow of patients with ischemic stroke by elevation of blood pressure (BP). We aimed to investigate if cerebral augmentation effects during ECP were associated with impaired dynamic cerebral autoregulation in patients after acute ischemic stroke. Methods Forty patients with unilateral ischemic stroke and large artery atherosclerosis in the anterior circulation territory within 7 days from symptom onset and eighteen healthy controls were recruited. We monitored changes in mean flow velocity over both middle cerebral arteries (MCA) by transcranial Doppler (TCD) before, during, and immediately after ECP. Cerebral augmentation index was MCA mean flow velocity increase in percentage during ECP compared with baseline to evaluate the augmentation effects of ECP. Spontaneous arterial BP and cerebral blood flow velocity in both bilateral MCAs were recorded using a servo-controlled plethysmograph and TCD, respectively. Transfer function analysis was used to derive the autoregulatory parameters, including phase difference (PD), and gain. Results The cerebral augmentation index in patients with stroke was significantly higher on both the ipsilateral and contralateral sides than that in controls, while the PD in patients with stroke was significantly lower on both sides than those in controls (all P < 0.05). The cerebral augmentation index did not correlate with PD and gain on either the ipsilateral or contralateral side of patients with stroke or in controls (all P > 0.05). The cerebral augmentation index of patients with stroke was significantly related to mean BP change on the ipsilateral side (R2 = 0.108, P = 0.038). Conclusion The degree of ECP-induced cerebral augmentation effects as measured by the cerebral augmentation index did not correlate with the magnitude of impaired dynamic cerebral autoregulation.
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Affiliation(s)
- Li Xiong
- Clinical Trials Centre, The Eighth Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
- Department of Medicine & Therapeutics, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
- *Correspondence: Li Xiong
| | - Xiangyan Chen
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Shatin, Hong Kong SAR, China
- Xiangyan Chen
| | - Jia Liu
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Lawrence Ka Sing Wong
- Department of Medicine & Therapeutics, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Thomas W. Leung
- Department of Medicine & Therapeutics, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
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Milanlioglu A, Yaman A, Kolukisa M, Asil T. Evaluation of cerebral hemodynamic status in patients with unilateral symptomatic carotid artery stenosis during motor tasks, through use of transcranial Doppler sonography. ARQUIVOS DE NEURO-PSIQUIATRIA 2022; 80:339-343. [PMID: 35019075 DOI: 10.1590/0004-282x-anp-2020-0571] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Accepted: 03/13/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND Carotid artery stenosis increases cerebral ischemic event risk through changing different cerebral hemodynamic parameters. OBJECTIVE To investigate how cerebral hemodynamics in the M1 segment of middle cerebral artery change in patients with carotid artery stenosis, after motor tasks using transcranial Doppler sonography (TCD). METHODS Thirty-two healthy subjects and 30 patients with unilateral symptomatic carotid artery stenosis were recruited. The patient population was divided into three groups according to the degree of stenosis (group 1: ≥50 to 69%, group 2: 70 to 89% and group 3: ≥90 to 99%). TCD was used to measure the pulsatility index (PI) and cerebral vasomotor reactivity (CVR). RESULTS In the patient group, significant differences for symptomatic side PI values (p=0.01) and mean CVR increases (p=0.05) were observed, compared with the healthy controls. However, the difference was not statistically significant for asymptomatic side PI values and mean CVR increases. The results from the intergroup comparison showed significantly higher percentages of symptomatic and asymptomatic side CVR increases in group 1, compared with groups 2 and 3 (p=0.001 and p=0.002, respectively). CONCLUSIONS Our study showed that cerebral autoregulation and hemodynamic mechanisms are impaired in patients with carotid artery stenosis. Furthermore, the impairment of PI and CVR tends to get worse with increasing degrees of stenosis. In addition, this study demonstrated that assessment of these two hemodynamic parameters in clinical practice might be helpful for monitoring the progress of carotid artery stenosis.
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Affiliation(s)
- Aysel Milanlioglu
- Yüzüncü Yıl University, Faculty of Medicine, Department of Neurology, Van, Turkey
| | - Aslı Yaman
- Bezmialem Vakıf University, Faculty of Medicine, Department of Neurology, İstanbul, Turkey
| | - Mehmet Kolukisa
- Bezmialem Vakıf University, Faculty of Medicine, Department of Neurology, İstanbul, Turkey
| | - Talip Asil
- Bezmialem Vakıf University, Faculty of Medicine, Department of Neurology, İstanbul, Turkey
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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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Huo R, Xu H, Yang D, Qiao H, Li J, Han H, Liu Y, Wang T, Yuan H, Zhao X. Associations Between Carotid Plaque Characteristics and Improvement of Cerebral Blood Perfusion in Patients With Moderate to Severe Carotid Stenosis Undergoing Carotid Endarterectomy. J Magn Reson Imaging 2020; 53:613-625. [PMID: 33037860 DOI: 10.1002/jmri.27365] [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: 06/01/2020] [Revised: 08/31/2020] [Accepted: 09/01/2020] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND The relationship between plaque characteristics and their predictive value for perioperative cerebral blood flow (CBF) are unknown. PURPOSE To investigate the relationship between carotid plaque characteristics and perioperative CBF utilizing MRI. STUDY TYPE Prospective. POPULATION In all, 131 patients with carotid moderate-to-severe stenosis referred for carotid endarterectomy (CEA). FIELD STRENGTH/SEQUENCE 3T, black-blood T1 - and T2 -weighted, 3D time-of-flight, and simultaneous noncontrast angiography intraplaque hemorrhage. ASSESSMENT The relative CBF (rCBF = CBFindex-hemisphere /CBFcontralateral-hemisphere ) and the CBF difference ratio (DRCBF = [CBFpost-CEA - CBFpre-CEA ]/CBFpre-CEA ) in the middle cerebral artery territory were measured. The pre- and post-CEA CTP data were used as the assessment standard for CBF change. Carotid lipid-rich necrotic core (LRNC), intraplaque hemorrhage, calcification, fibrous cap rupture, maximum wall thickness, normalized wall index (NWI), and stenosis were determined. STATISTICAL TESTS Pearson or Spearman correlation, Mann-Whitney U-test, and linear regression. RESULTS Patients with LRNC had higher rCBFpre-CEA than those without (1.0 ± 0.1 vs. 0.9 ± 0.1, P < 0.05). NWI was weakly correlated with rCBFpre-CEA (r = -0.213, P < 0.05) and DRCBF (r = 0.185, P < 0.05) and marginally correlated with rCBFpost-CEA (r = 0.166, P = 0.057). LRNC was weakly correlated with rCBFpre-CEA (r = 0.179, P < 0.05). NWI was associated with rCBFpre-CEA (β = -0.035; 95% confidence interval [CI] [-0.064, -0.006]; P < 0.05), rCBFpost-CEA (β = 0.042; 95% CI [0.002, 0.081]; P < 0.05) and DRCBF (β = 0.105; 95% CI [0.026, 0.185]; P < 0.05). After adjusting for confounding factors, associations of NWI with rCBFpost-CEA (β = 0.059; 95% CI [0.016, 0.103]; P < 0.05) and DRCBF (β = 0.110; 95% CI [0.021, 0.199]; P < 0.05) remained statistically significant, while the association between NWI and rCBFpre-CEA was no longer significant (β = -0.026; 95% CI [-0.058, 0.006]; P = 0.112).The associations of LRNC with rCBFpre-CEA (β = 0.057; 95% CI [-0.0006, 0.114]; P = 0.052) and DRCBF (β = -0.157; 95% CI [-0.314, 0.001]; P = 0.051) were close to statistical significance. After adjusting for confounding factors, these associations were statistically significant (of LRNC vs. rCBFpre-CEA : β = 0.060; 95% CI [0.003, 0.118]; P < 0.05; LRNC vs. DRCBF : β = -0.205; 95% CI [-0.375, -0.036]; P < 0.05). DATA CONCLUSION Carotid plaque burden and components, particularly LRNC, might be effective indicators for CBF change following CEA. Level of Evidence 1 Technical Efficacy Stage 5.
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Affiliation(s)
- Ran Huo
- Department of Radiology, Peking University Third Hospital, Beijing, China
| | - Huimin Xu
- Department of Radiology, Peking University Third Hospital, Beijing, China
| | - Dandan Yang
- Center for Brain Disorders Research, Capital Medical University and Beijing Institute for Brain Disorders, Beijing, China.,Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China
| | - Huiyu Qiao
- Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China
| | - Jin Li
- Department of Radiology, The Affiliated BenQ Hospital of Nanjing Medical University, Nanjing, China
| | - Hualu Han
- Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China
| | - Ying Liu
- Department of Radiology, Peking University Third Hospital, Beijing, China
| | - Tao Wang
- Department of Neurosurgery, Peking University Third Hospital, Beijing, China
| | - Huishu Yuan
- Department of Radiology, Peking University Third Hospital, Beijing, China
| | - Xihai Zhao
- Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China
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12
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Gad H, Khan A, Akhtar N, Kamran S, El-Sotouhy A, Dargham SR, Petropoulos IN, Ponirakis G, Shuaib A, Streletz LJ, Malik RA. Corneal nerve and endothelial cell damage in patients with transient ischemic attack and minor ischemic stroke. PLoS One 2019; 14:e0213319. [PMID: 30875374 PMCID: PMC6420175 DOI: 10.1371/journal.pone.0213319] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 02/18/2019] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVE To determine if corneal confocal microscopy can identify corneal nerve and endothelial cell abnormalities and may be useful in the prognostication of patients with transient ischemic attack [1] or minor ischemic stroke (IS). METHODS Thirty-six patients admitted with TIA (n = 14) or minor IS (n = 22) underwent transcranial Doppler evaluation and corneal confocal microscopy and were compared with 18 healthy controls. RESULTS Corneal nerve fiber density (P = 0.002), branch density (P = 0.004) and fiber length (P = 0.004) were significantly lower in patients with TIA or minor IS compared to controls, with no difference between patients with TIA and minor IS. Endothelial cell density (P = 0.003) was lower and endothelial cell area (P = 0.003) and perimeter (P = 0.006) were significantly higher in patients with TIA or minor IS compared to controls, with no difference between patients with TIA and minor IS. There were no differences in corneal nerve or endothelial cell morphology between patients with and without abnormal cerebrovascular reactivity. HbA1c was independently associated with CNFL, and endothelial cell polymegathism and pleomorphism were associated with both HbA1c and total cholesterol. CONCLUSION Corneal confocal microscopy identifies corneal nerve fiber loss and endothelial cell abnormalities in patients with TIA and minor IS and independent associations with HbA1c and cholesterol.
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Affiliation(s)
- Hoda Gad
- Department of Medicine, Weill Cornell Medicine-Qatar, Doha, Qatar
| | - Adnan Khan
- Department of Medicine, Weill Cornell Medicine-Qatar, Doha, Qatar
| | - Naveed Akhtar
- Institute of Neurosciences, Hamad Medical Corporation, Doha, Qatar
| | - Saadat Kamran
- Institute of Neurosciences, Hamad Medical Corporation, Doha, Qatar
| | | | - Soha R. Dargham
- Biostatistics, Epidemiology & Biomathematics Research Core, Weill Cornell Medicine-Qatar, Doha, Qatar
| | | | | | - Ashfaq Shuaib
- Institute of Neurosciences, Hamad Medical Corporation, Doha, Qatar
- Department of Medicine, University of Alberta, Edmonton, Canada
| | - Leopold J. Streletz
- Department of Medicine, Weill Cornell Medicine-Qatar, Doha, Qatar
- Institute of Neurosciences, Hamad Medical Corporation, Doha, Qatar
| | - Rayaz A. Malik
- Department of Medicine, Weill Cornell Medicine-Qatar, Doha, Qatar
- Institute of Cardiovascular Medicine, University of Manchester, Manchester, United Kingdom
- * E-mail:
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13
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Sanders ML, Claassen JAHR, Aries M, Bor-Seng-Shu E, Caicedo A, Chacon M, Gommer ED, Van Huffel S, Jara JL, Kostoglou K, Mahdi A, Marmarelis VZ, Mitsis GD, Müller M, Nikolic D, Nogueira RC, Payne SJ, Puppo C, Shin DC, Simpson DM, Tarumi T, Yelicich B, Zhang R, Panerai RB, Elting JWJ. Reproducibility of dynamic cerebral autoregulation parameters: a multi-centre, multi-method study. Physiol Meas 2018; 39:125002. [PMID: 30523976 DOI: 10.1088/1361-6579/aae9fd] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
OBJECTIVE Different methods to calculate dynamic cerebral autoregulation (dCA) parameters are available. However, most of these methods demonstrate poor reproducibility that limit their reliability for clinical use. Inter-centre differences in study protocols, modelling approaches and default parameter settings have all led to a lack of standardisation and comparability between studies. We evaluated reproducibility of dCA parameters by assessing systematic errors in surrogate data resulting from different modelling techniques. APPROACH Fourteen centres analysed 22 datasets consisting of two repeated physiological blood pressure measurements with surrogate cerebral blood flow velocity signals, generated using Tiecks curves (autoregulation index, ARI 0-9) and added noise. For reproducibility, dCA methods were grouped in three broad categories: 1. Transfer function analysis (TFA)-like output; 2. ARI-like output; 3. Correlation coefficient-like output. For all methods, reproducibility was determined by one-way intraclass correlation coefficient analysis (ICC). MAIN RESULTS For TFA-like methods the mean (SD; [range]) ICC gain was 0.71 (0.10; [0.49-0.86]) and 0.80 (0.17; [0.36-0.94]) for VLF and LF (p = 0.003) respectively. For phase, ICC values were 0.53 (0.21; [0.09-0.80]) for VLF, and 0.92 (0.13; [0.44-1.00]) for LF (p < 0.001). Finally, ICC for ARI-like methods was equal to 0.84 (0.19; [0.41-0.94]), and for correlation-like methods, ICC was 0.21 (0.21; [0.056-0.35]). SIGNIFICANCE When applied to realistic surrogate data, free from the additional exogenous influences of physiological variability on cerebral blood flow, most methods of dCA modelling showed ICC values considerably higher than what has been reported for physiological data. This finding suggests that the poor reproducibility reported by previous studies may be mainly due to the inherent physiological variability of cerebral blood flow regulatory mechanisms rather than related to (stationary) random noise and the signal analysis methods.
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Affiliation(s)
- Marit L Sanders
- Department of Geriatric Medicine, Radboudumc Alzheimer Centre and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
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14
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Chen DW, Zheng J, Shi J, Yin YW, Song C, Yang F, Zhang YQ, Ma LN. Assessment of the Cerebral Hemodynamic Benefits of Carotid Artery Stenting for Patients with Preoperative Hemodynamic Impairment Using Cerebral Single Photon Emission Computed Tomography (SPECT) and Carbon Dioxide Inhalation. Med Sci Monit 2018; 24:5398-5404. [PMID: 30074982 PMCID: PMC6087634 DOI: 10.12659/msm.909401] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND The aim of this study was to evaluate the effects of carotid artery angioplasty and carotid artery stenting (CAS) on cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) in patients with preoperative cerebrovascular hemodynamic impairment. MATERIAL AND METHODS Seventeen patients with unilateral severe internal carotid artery (ICA) stenosis and ipsilateral CVR impairment underwent CAS. CBF and CVR were measured by single photon emission computed tomography (SPECT) with inhalation of carbon dioxide (CO2) one week before and three months after CAS. Sixty-eight ROIs in the middle cerebral artery (MCA) territory were analyzed in 17 patients. RESULTS Before CAS, CVR was impaired in all ROIs. CBF was impaired in 16 ROIs (23.5%). The percentage of ROIs with impaired CBF was significantly increased in patients with ≥90% carotid artery stenosis (p=0.047) without collateral flow through the circle of Willis (p=0.005). CAS significantly increased CVR in ROIs with a normal preoperative CBF and impaired CVR, indicating mild hemodynamic impairment (0.9±6.7% vs. 4.9±8.6%) (p=0.014). CAS significantly increased CBF in ROIs with preoperative impaired CBF and impaired CVR, indicating severe hemodynamic impairment (79.1±7.5% vs. 86.7±10.0%) (p<0.001). Following CAS, ROIs with normal CBF and impaired CVR had a significantly increased percentage of improved CVR (p=0.047); ROIs with impaired CBF and impaired CVR had a significantly increased percentage of improved CBF (p=0.027). CONCLUSIONS The severity of preoperative hemodynamic impairment, which is related to the degree of carotid artery stenosis and cerebral collateral flow, may influence hemodynamic benefits by CAS.
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Affiliation(s)
- Da-Wei Chen
- Department of Neurology, Air Force General Hospital of the Chinese Peoples' Liberation Army, Beijing, China (mainland)
| | - Jin Zheng
- Department of Neurology, Tongde Hospital of Zhejiang Province, Hangzhou, Zhejiang, China (mainland)
| | - Jin Shi
- Department of Neurology, Air Force General Hospital of the Chinese Peoples' Liberation Army, Beijing, China (mainland)
| | - Yang-Wei Yin
- Department of Neurology, Air Force General Hospital of the Chinese Peoples' Liberation Army, Beijing, China (mainland)
| | - Chen Song
- Department of Neurology, Air Force General Hospital of the Chinese Peoples' Liberation Army, Beijing, China (mainland)
| | - Fen Yang
- Department of Neurology, Air Force General Hospital of the Chinese Peoples' Liberation Army, Beijing, China (mainland)
| | - Ying-Qian Zhang
- Department of Neurology, Air Force General Hospital of the Chinese Peoples' Liberation Army, Beijing, China (mainland)
| | - Lu-Na Ma
- Positron Emission Tomography (PET) Center, Air Force General Hospital of the Chinese Peoples' Liberation Army, Beijing, China (mainland)
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15
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Guo ZN, Sun X, Liu J, Sun H, Zhao Y, Ma H, Xu B, Wang Z, Li C, Yan X, Zhou H, Zhang P, Jin H, Yang Y. The Impact of Variational Primary Collaterals on Cerebral Autoregulation. Front Physiol 2018; 9:759. [PMID: 29971018 PMCID: PMC6018219 DOI: 10.3389/fphys.2018.00759] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Accepted: 05/30/2018] [Indexed: 11/13/2022] Open
Abstract
The influence of the anterior and posterior communicating artery (ACoA and PCoA) on dynamic cerebral autoregulation (dCA) is largely unknown. In this study, we aimed to test whether substantial differences in collateral anatomy were associated with differences in dCA in two common types of stenosis according to digital subtraction angiography (DSA): either isolated basal artery and/or bilateral vertebral arteries severe stenosis/occlusion (group 1; group 1A: with bilateral PCoAs; and group 1B: without bilateral PCoAs), or isolated unilateral internal carotid artery severe stenosis/occlusion (group 2; group 2A: without ACoA and with PCoA; group 2B: with ACoA and without PCoAs; and group 2C: without both ACoA and PCoA). The dCA was calculated by transfer function analysis (a mathematical model), and was evaluated in middle cerebral artery (MCA) and/or posterior cerebral artery (PCA). Of a total of 231 non-acute phase ischemic stroke patients who received both dCA assessment and DSA in our lab between 2014 and 2017, 51 patients met inclusion criteria based on the presence or absence of ACoA or PCoA, including 21 patients in the group 1, and 30 patients in the group 2. There were no significant differences in gender, age, and mean blood pressure between group 1A and group 1B, and among group 2A, group 2B, and group 2C. In group 1, the PCA phase difference values (autoregulatory parameter) were significantly higher in the subgroup with patent PCoAs, compared to those without. In group 2, the MCA phase difference values were higher in the subgroup with patent ACoA, compared to those without. This pilot study found that the cross-flow of the ACoA/PCoA to the affected area compensates for compromised dCA in the affected area, which suggests an important role of the ACoA/PCoA in stabilizing cerebral blood flow.
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Affiliation(s)
- Zhen-Ni Guo
- Department of Neurology, The First Hospital of Jilin University, Changchun, China.,Department of Neurology, Clinical Trial and Research Center for Stroke, The First Hospital of Jilin University, Changchun, China
| | - Xin Sun
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Jia Liu
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, University Town of Shenzhen, Shenzhen, 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
| | - Hongyin Ma
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Baofeng Xu
- Department of Neurosurgery, The First Hospital of Jilin University, Changchun, China
| | - Zhongxiu Wang
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Chao Li
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Xiuli Yan
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Hongwei Zhou
- Department of Radiology, The First Hospital of Jilin University, Changchun, China
| | - Peng Zhang
- Department of Neurology, Clinical Trial and Research Center for Stroke, The First Hospital of Jilin University, Changchun, China
| | - Hang Jin
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Yi Yang
- Department of Neurology, The First Hospital of Jilin University, Changchun, China.,Department of Neurology, Clinical Trial and Research Center for Stroke, The First Hospital of Jilin University, Changchun, China
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16
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Abstract
PURPOSE OF REVIEW Cerebral autoregulation (CA) is a mechanism that maintains cerebral blood flow constant despite fluctuations in systemic arterial blood pressure. This review will focus on recent studies that measured CA non-invasively in acute cerebrovascular events, a feature unique to the transcranial Doppler ultrasound. We will summarize the rationale for CA assessment in acute cerebrovascular disorders and specifically evaluate the existing data on the value of CA measures in relation to clinical severity, guiding management decisions, and prognostication. RECENT FINDINGS Existing data suggest that CA is generally impaired in various cerebrovascular disorders. In patients with small vessel ischemic stroke, CA has been shown to be impaired in both hemispheres, whereas in large territorial strokes, CA impairment has been limited to the affected hemisphere. In these latter patients, impaired CA is also predictive of secondary complications such as hemorrhagic transformation and cerebral edema, hence worse functional outcome. In patients with carotid stenosis, impaired CA may also be associated with a higher ipsilateral hemispheric stroke risk. CA is also strongly linked to outcome in patients with intracranial hemorrhage. In patients with intraparenchymal hemorrhage, CA impairment correlated with clinical and imaging severity, whereas in those with subarachnoid hemorrhage, CA measures have a predictive value for development of delayed cerebral ischemia and radiographic vasospasm. Assessment of CA is increasingly more accessible in acute cerebrovascular disorders and promises to be a valuable measure in guiding hemodynamic management and predicting secondary complication, thus enhancing the care of these patients in the acute setting.
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Affiliation(s)
- Pedro Castro
- Department of Neurology, São João Hospital Center, Porto, Portugal.,Department of Clinical Neurosciences and Mental Health, Faculty of Medicine of University of Porto, Porto, Portugal
| | - Elsa Azevedo
- Department of Neurology, São João Hospital Center, Porto, Portugal.,Department of Clinical Neurosciences and Mental Health, Faculty of Medicine of University of Porto, Porto, Portugal
| | - Farzaneh Sorond
- Department of Neurology, Division of Stroke and Neurocritical, Northwestern University Feinberg School of Medicine, 303 East Chicago Avenue, Ward 12-140, Chicago, IL, 60611, USA.
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17
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Tanaka H, Watanabe Y, Nakamura H, Takahashi H, Arisawa A, Fujiwara T, Matsuo C, Tomiyama N. Multiple blood flow measurements before and after carotid artery stenting via phase-contrast magnetic resonance imaging: An observational study. PLoS One 2018; 13:e0195099. [PMID: 29641548 PMCID: PMC5895018 DOI: 10.1371/journal.pone.0195099] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2017] [Accepted: 03/18/2018] [Indexed: 11/19/2022] Open
Abstract
After carotid artery stenting, the procurement of information about blood flow redistribution among brain-feeding arteries and its time trend is essential to understanding a patient’s physiological background and to determine their care regimen. Cerebral blood flow has been measured twice following carotid artery stenting in few previous studies, with some discrepancies in the results. The purpose of this study was to measure cerebral blood flow at multiple time points after carotid artery stenting, and to elucidate the time trend of cerebral blood flow and redistribution among arteries. Blood flow rates in 11 subjects were measured preoperatively, at one day, one week, and about three months, respectively after carotid artery stenting by using phase-contrast magnetic resonance imaging. The target vessels were the bilateral internal carotid arteries, the basilar artery, and the bilateral middle cerebral arteries. Lumen was semi-automatically defined using an algorithm utilizing pulsatility. The results showed that blood flow rates in the stented internal carotid artery and the ipsilateral middle cerebral artery increased following carotid artery stenting. Blood flow rates in the contralateral internal carotid artery and the basilar artery gradually declined, and they were lower than the preoperative values at three months after stenting. The sum of blood flow rates of the bilateral internal carotid arteries and the basilar artery increased after carotid artery stenting, and then decreased over the next three months. There was no significant change in the blood flow rate in the contralateral middle cerebral artery. From these results, it was concluded that redistribution among the bilateral internal carotid arteries and the basilar artery occurs after carotid artery stenting, and that it takes months thereafter to reach another equilibrium.
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Affiliation(s)
- Hisashi Tanaka
- Department of Radiology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
- * E-mail:
| | - Yoshiyuki Watanabe
- Department of Radiology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Hajime Nakamura
- Department of Neurosurgery, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Hiroto Takahashi
- Department of Radiology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Atsuko Arisawa
- Department of Radiology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Takuya Fujiwara
- Department of Radiology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Chisato Matsuo
- Department of Radiology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Noriyuki Tomiyama
- Department of Radiology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
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18
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Hansen AB, Hoiland RL, Lewis NCS, Tymko MM, Tremblay JC, Stembridge M, Nowak-Flück D, Carter HH, Bailey DM, Ainslie PN. UBC-Nepal expedition: The use of oral antioxidants does not alter cerebrovascular function at sea level or high altitude. Exp Physiol 2018; 103:523-534. [DOI: 10.1113/ep086887] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 02/05/2018] [Indexed: 12/19/2022]
Affiliation(s)
- Alexander B. Hansen
- Centre for Heart, Lung & Vascular Health, School of Health and Exercise Sciences; University of British Columbia, Okanagan Campus; Kelowna BC Canada
| | - Ryan L. Hoiland
- Centre for Heart, Lung & Vascular Health, School of Health and Exercise Sciences; University of British Columbia, Okanagan Campus; Kelowna BC Canada
| | - Nia C. S. Lewis
- Centre for Heart, Lung & Vascular Health, School of Health and Exercise Sciences; University of British Columbia, Okanagan Campus; Kelowna BC Canada
| | - Michael M. Tymko
- Centre for Heart, Lung & Vascular Health, School of Health and Exercise Sciences; University of British Columbia, Okanagan Campus; Kelowna BC Canada
| | - Joshua C. Tremblay
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies; Queen's University; Kingston ON Canada
| | - Michael Stembridge
- Cardiff Centre for Exercise and Health; Cardiff Metropolitan University; Cardiff UK
| | - Daniela Nowak-Flück
- Centre for Heart, Lung & Vascular Health, School of Health and Exercise Sciences; University of British Columbia, Okanagan Campus; Kelowna BC Canada
| | - Howard H. Carter
- Department of Nutrition, Exercise and Sports; University of Copenhagen; Copenhagen Denmark
| | - Damian M. Bailey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education; University of South Wales; Newport UK
| | - Philip N. Ainslie
- Centre for Heart, Lung & Vascular Health, School of Health and Exercise Sciences; University of British Columbia, Okanagan Campus; Kelowna BC Canada
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Semenyutin VB, Asaturyan GA, Nikiforova AA, Aliev VA, Panuntsev GK, Iblyaminov VB, Savello AV, Patzak A. Predictive Value of Dynamic Cerebral Autoregulation Assessment in Surgical Management of Patients with High-Grade Carotid Artery Stenosis. Front Physiol 2017; 8:872. [PMID: 29163214 PMCID: PMC5673646 DOI: 10.3389/fphys.2017.00872] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Accepted: 10/17/2017] [Indexed: 01/20/2023] Open
Abstract
Dynamic cerebral autoregulation (DCA) capacity along with the degree of internal carotid artery (ICA) stenosis and characteristics of the plaque can also play an important role in selection of appropriate treatment strategy. This study aims to classify the patients with severe ICA stenosis according to preoperative state of DCA and to assess its dynamics after surgery. Thirty-five patients with severe ICA stenosis having different clinical type of disease underwent reconstructive surgery. DCA was assessed with transfer function analysis (TFA) by calculating phase shift (PS) between Mayer waves of blood flow velocity (BFV) and blood pressure (BP) before and after operation. In 18 cases, regardless of clinical type, preoperative PS on ipsilateral side was within the normal range and did not change considerably after surgery. In other 17 cases preoperative PS was reliably lower both in patients with symptomatic and asymptomatic stenosis. Surgical reconstruction led to restoration of impaired DCA evidenced by significant increase of PS in postoperative period. Our data suggest that regardless clinical type of disease various state of DCA may be present in patients with severe ICA stenosis. This finding can contribute to establishing the optimal treatment strategy, and first of all for asymptomatic patients. Patients with compromised DCA should be considered as ones with higher risk of stroke and first candidates for reconstructive surgery.
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Affiliation(s)
- Vladimir B Semenyutin
- Laboratory of Brain Circulation Pathology, Federal Almazov Medical Research Center, Saint-Petersburg, Russia
| | - Gregory A Asaturyan
- Laboratory of Brain Circulation Pathology, Federal Almazov Medical Research Center, Saint-Petersburg, Russia
| | - Anna A Nikiforova
- Laboratory of Brain Circulation Pathology, Federal Almazov Medical Research Center, Saint-Petersburg, Russia
| | - Vugar A Aliev
- Laboratory of Brain Circulation Pathology, Federal Almazov Medical Research Center, Saint-Petersburg, Russia.,Department of Neurosurgery, Municipal Hospital of Saint Martyr Elizabeth, Saint-Petersburg, Russia
| | - Grigory K Panuntsev
- Laboratory of Brain Circulation Pathology, Federal Almazov Medical Research Center, Saint-Petersburg, Russia
| | - Vadim B Iblyaminov
- Laboratory of Brain Circulation Pathology, Federal Almazov Medical Research Center, Saint-Petersburg, Russia
| | - Alexander V Savello
- Laboratory of Brain Circulation Pathology, Federal Almazov Medical Research Center, Saint-Petersburg, Russia
| | - Andreas Patzak
- Johannes-Mueller Institute of Physiology University Hospital Charite, Humboldt University of Berlin, Berlin, Germany
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20
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Semenyutin VB, Asaturyan GА, Nikiforova АА, Panuntsev GК, Aliev VA, Iblyaminov VB, Savello AV, Patzak А, Laptev KV, Dudanov IP, Pavlov ОА. [Severe carotid stenosis: cerebral autoregulation in the ipsilateral region]. Zh Nevrol Psikhiatr Im S S Korsakova 2017; 117:76-84. [PMID: 28884722 DOI: 10.17116/jnevro20171178176-84] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
AIM To study cerebral autoregulation (CA) in region of the stenotic carotid artery. MATERIAL AND METHODS The study involved 35 patients with critical stenosis of the carotid arteries, including 24 patients were asymptomatic and 11 patients with symptomatic course. Blood flow velocity in middle cerebral arteries was monitored using Multi Dop X (DWL, Germany) with simultaneous noninvasive systemic blood pressure registration (CNAP, Austria). CA was assessed by calculating the phase shift (PS) between spontaneous oscillations of blood flow velocity and blood pressure within the range of systemic Mayer waves (80-120 mHz). RESULTS In 18 patients, the CA indicators were in the normal range (PS 1.2±0.3 rad). Seventeen patients, including asymptomatic as well as symptomatic types, had impaired CA (PS 0.2±0.2 rad and 0.3±0.2 rad, respectively). Reconstructive surgery, irrespective of clinical manifestations, led to the significant increase in PS (p<0.001) in the early postoperative period (0.9±0.5 and 0.9±0.3 rad, respectively). CONCLUSION A significant variability in the cerebrovascular reserve capacity in symptomatic and asymptomatic types of carotid artery stenosis was found. CA can be used in determining the indications for surgical treatment and evaluation of its effectiveness in patients with stenosis of carotid arteries.
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Affiliation(s)
- V B Semenyutin
- Almazov Northwest Federal Medical Research Centre, St. Petersburg, Russia
| | - G А Asaturyan
- Almazov Northwest Federal Medical Research Centre, St. Petersburg, Russia
| | - А А Nikiforova
- Almazov Northwest Federal Medical Research Centre, St. Petersburg, Russia
| | - G К Panuntsev
- Almazov Northwest Federal Medical Research Centre, St. Petersburg, Russia
| | - V A Aliev
- Almazov Northwest Federal Medical Research Centre, St. Petersburg, Russia
| | - V B Iblyaminov
- Almazov Northwest Federal Medical Research Centre, St. Petersburg, Russia
| | - A V Savello
- Almazov Northwest Federal Medical Research Centre, St. Petersburg, Russia
| | - А Patzak
- Johannes-Mueller Institute of Physiology University Hospital Charite, Humboldt-University of Berlin, Berlin, Germany
| | - K V Laptev
- Municipal Mariinsky Hospital, St. Petersburg, Russia
| | - I P Dudanov
- Municipal Mariinsky Hospital, St. Petersburg, Russia
| | - О А Pavlov
- Municipal Mariinsky Hospital, St. Petersburg, Russia
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Hori D, Nomura Y, Ono M, Joshi B, Mandal K, Cameron D, Kocherginsky M, Hogue CW. Optimal blood pressure during cardiopulmonary bypass defined by cerebral autoregulation monitoring. J Thorac Cardiovasc Surg 2017; 154:1590-1598.e2. [PMID: 29042040 DOI: 10.1016/j.jtcvs.2017.04.091] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 03/29/2017] [Accepted: 04/10/2017] [Indexed: 12/13/2022]
Abstract
OBJECTIVES We sought to define the lower and upper limits of cerebral blood flow autoregulation and the optimal blood pressure during cardiopulmonary bypass. We further sought to identify variables predictive of these autoregulation end points. METHODS Cerebral autoregulation was monitored continuously with transcranial Doppler in 614 patients during cardiopulmonary bypass enrolled in 3 investigations. A moving Pearson's correlation coefficient was calculated between cerebral blood flow velocity and mean arterial pressure to generate the variable mean velocity index. Optimal mean arterial pressure was defined as the mean arterial pressure with the lowest mean velocity index indicating the best autoregulation. The lower and upper limits of cerebral blood flow autoregulation were defined as the mean arterial pressure at which mean velocity index was increasingly pressure passive (ie, mean velocity index ≥0.4) with declining or increasing blood pressure, respectively. RESULTS The mean (± standard deviation) lower and upper limits of cerebral blood flow autoregulation, and optimal mean arterial pressure were 65 ± 12 mm Hg, 84 ± 11 mm Hg, and 78 ± 11 mm Hg, respectively, after adjusting for study enrollment. In 17% of patients, though, the lower limit of cerebral autoregulation was above this optimal mean arterial pressure, whereas in 29% of patients the upper limit of autoregulation was below the population optimal mean arterial pressure. Variables associated with optimal mean arterial pressure based on multivariate regression analysis were nonwhite race (increased 2.7 mm Hg; P = .034), diuretics use (decreased 1.9 mm Hg; P = .049), prior carotid endarterectomy (decreased 5.5 mm Hg; P = .019), and duration of cardiopulmonary bypass (decreased 1.28 per 60 minutes of cardiopulmonary bypass). The product of the duration and magnitude that mean arterial pressure during cardiopulmonary bypass was below the lower limit of cerebral autoregulation was associated with the risk for stroke (P = .02). CONCLUSIONS Real-time monitoring of autoregulation may improve individualizing mean arterial pressure during cardiopulmonary bypass and improving patient outcomes.
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Affiliation(s)
- Daijiro Hori
- Division of Cardiac Surgery, Department of Surgery, The Johns Hopkins University School of Medicine, Baltimore, Md
| | - Yohei Nomura
- Division of Cardiac Surgery, Department of Surgery, The Johns Hopkins University School of Medicine, Baltimore, Md
| | - Masahiro Ono
- Department of Cardiac Surgery, The Texas Heart Institute, Houston, Tex
| | - Brijen Joshi
- Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine, Baltimore, Md
| | - Kaushik Mandal
- Division of Cardiac Surgery, Department of Surgery, The Johns Hopkins University School of Medicine, Baltimore, Md
| | - Duke Cameron
- Division of Cardiac Surgery, Department of Surgery, The Johns Hopkins University School of Medicine, Baltimore, Md
| | - Masha Kocherginsky
- Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, Ill
| | - Charles W Hogue
- Department of Anesthesiology and the Bluhm Cardiovascular Institute, Northwestern University Feinberg School of Medicine, Chicago, Ill.
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Multiple Factors Involved in the Pathogenesis of White Matter Lesions. BIOMED RESEARCH INTERNATIONAL 2017; 2017:9372050. [PMID: 28316994 PMCID: PMC5339523 DOI: 10.1155/2017/9372050] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 01/09/2017] [Accepted: 01/26/2017] [Indexed: 12/19/2022]
Abstract
White matter lesions (WMLs), also known as leukoaraiosis (LA) or white matter hyperintensities (WMHs), are characterized mainly by hyperintensities on T2-weighted or fluid-attenuated inversion recovery (FLAIR) images. With the aging of the population and the development of imaging technology, the morbidity and diagnostic rates of WMLs are increasing annually. WMLs are not a benign process. They clinically manifest as cognitive decline and the subsequent development of dementia. Although WMLs are important, their pathogenesis is still unclear. This review elaborates on the advances in the understanding of the pathogenesis of WMLs, focusing on anatomy, cerebral blood flow autoregulation, venous collagenosis, blood brain barrier disruption, and genetic factors. In particular, the attribution of WMLs to chronic ischemia secondary to venous collagenosis and cerebral blood flow autoregulation disruption seems reasonable. With the development of gene technology, the effect of genetic factors on the pathogenesis of WMLs is gaining gradual attention.
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Haubrich C, Czosnyka M, Diehl R, Smielewski P, Czosnyka Z. Ventricular Volume Load Reveals the Mechanoelastic Impact of Communicating Hydrocephalus on Dynamic Cerebral Autoregulation. PLoS One 2016; 11:e0158506. [PMID: 27415784 PMCID: PMC4944997 DOI: 10.1371/journal.pone.0158506] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 06/16/2016] [Indexed: 11/18/2022] Open
Abstract
Several studies have shown that the progression of communicating hydrocephalus is associated with diminished cerebral perfusion and microangiopathy. If communicating hydrocephalus similarly alters the cerebrospinal fluid circulation and cerebral blood flow, both may be related to intracranial mechanoelastic properties as, for instance, the volume pressure compliance. Twenty-three shunted patients with communicating hydrocephalus underwent intraventricular constant-flow infusion with Hartmann's solution. The monitoring included transcranial Doppler (TCD) flow velocities (FV) in the middle (MCA) and posterior cerebral arteries (PCA), intracranial pressure (ICP), and systemic arterial blood pressure (ABP). The analysis covered cerebral perfusion pressure (CPP), the index of pressure-volume compensatory reserve (RAP), and phase shift angles between Mayer waves (3 to 9 cpm) in ABP and MCA-FV or PCA-FV. Due to intraventricular infusion, the pressure-volume reserve was exhausted (RAP) 0.84+/-0.1 and ICP was increased from baseline 11.5+/-5.6 to plateau levels of 20.7+/-6.4 mmHg. The ratio dRAP/dICP distinguished patients with large 0.1+/-0.01, medium 0.05+/-0.02, and small 0.02+/-0.01 intracranial volume compliances. Both M wave phase shift angles (r = 0.64; p<0.01) and CPP (r = 0.36; p<0.05) displayed a gradual decline with decreasing dRAP/dICP gradients. This study showed that in communicating hydrocephalus, CPP and dynamic cerebral autoregulation in particular, depend on the volume-pressure compliance. The results suggested that the alteration of mechanoelastic characteristics contributes to a reduced cerebral perfusion and a loss of autonomy of cerebral blood flow regulation. Results warrant a prospective TCD follow-up to verify whether the alteration of dynamic cerebral autoregulation may indicate a progression of communicating hydrocephalus.
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Affiliation(s)
- Christina Haubrich
- Department of Academic Neurosurgery, Addenbrooke’s Hospital, Cambridge, United Kingdom
- Department of Neurology, University Hospital Aachen, Aachen, Germany
- * E-mail:
| | - Marek Czosnyka
- Department of Academic Neurosurgery, Addenbrooke’s Hospital, Cambridge, United Kingdom
| | - Rolf Diehl
- Department of Neurology, Alfried-Krupp-Krankenhaus, Essen, Germany
| | - Peter Smielewski
- Department of Academic Neurosurgery, Addenbrooke’s Hospital, Cambridge, United Kingdom
| | - Zofia Czosnyka
- Department of Academic Neurosurgery, Addenbrooke’s Hospital, Cambridge, United Kingdom
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Kuznetsov MP, Fedin AI, Karalkin AV, Frolov KB, Kunitsin NV, Yumin SM, Kholopova EA, Knyazev AV. [The efficacy of pharmacological preconditioning in carotid endarterectomy]. Zh Nevrol Psikhiatr Im S S Korsakova 2016; 116:34-41. [PMID: 27029445 DOI: 10.17116/jnevro20161162134-41] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE To assess the efficacy of pharmacological preconditioning with actovegin in carotid endarterectomy. MATERIAL AND METHODS The study was based on the results of surgical treatment of 80 patients with hemodynamically significant uni- and bilateral lesions of carotid arteries. Half of the patients was operated immediately and others after pharmacological preconditioning with actovegin in dose of 1200 mg/daily during 1,5 months. RESULTS Pharmacological preconditioning with actovegin increased the cerebral perfusion determined with one-photon emission computed tomography that improved significantly results of the surgery. There were significant changes in patient's state 7 days and 6 months after surgery. The improvement was correlated with the less number of asymptotic post-surgery ischemic strokes in different brain areas. CONCLUSION A positive role of pharmacological preconditioning with actovegin in surgical treatment of carotid artery stenosis has been demonstrated.
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Affiliation(s)
- M P Kuznetsov
- Pirogov Russian National Research Medical University, Moscow
| | - A I Fedin
- Pirogov Russian National Research Medical University, Moscow
| | | | | | | | - S M Yumin
- Pirogov Russian National Research Medical University, Moscow
| | - E A Kholopova
- Pirogov Russian National Research Medical University, Moscow
| | - A V Knyazev
- Pirogov Russian National Research Medical University, Moscow, Pirogov City Hospital #1, Moscow
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Zhang Y, Liu X, Steiner L, Smielewski P, Feen E, Pickard JD, Czosnyka M. Correlation Between Cerebral Autoregulation and Carbon Dioxide Reactivity in Patients with Traumatic Brain Injury. ACTA NEUROCHIRURGICA. SUPPLEMENT 2016; 122:205-9. [PMID: 27165907 DOI: 10.1007/978-3-319-22533-3_41] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
OBJECTIVE Cerebral blood flow autoregulation is commonly impaired in patients with traumatic brain injury (TBI). This study was to investigate correlations between cerebral autoregulation and CO2 reactivity in patients with TBI during transient mild hypocapnia. METHODS Patients with TBI who were on mechanical ventilation were hyperventilated for approximately 60 min. Indices of autoregulation, based on a model of the relationship between arterial blood pressure and blood flow velocity (FV) (ARIabp) and, separately, between cerebral perfusion pressure and FV (ARIcpp), were calculated. Mean flow index (Mx) was also calculated. RESULTS We investigated 31 consecutive patients. At baseline, median PaCO2 was 5.09 kPa (range 4.30-5.67 kPa); during hyperventilation, median PaCO2 was 4.38 kPa (range 3.72-4.96 kPa). ARI was associated with Mx (ARIabp vs. Mx: r = -0.39, p = 0.04; ARIcpp vs Mx: r = -0.67, p < 0.001). CO2 reactivity showed significant correlation with ARIcpp (r = 0.41, p = 0.04) and Mx (r = -0.37, p = 0.04). ARI after hyperventilation was significantly higher than ARI at baseline (ARIcpp: p = 0.02; ARIabp: p < 0.001). CONCLUSIONS Cerebral autoregulation seemed to be well linked to CO2 reactivity during transient hyperventilation. ARIcpp had a stronger correlation with CO2 reactivity than ARIabp. ARI indicated improvement of autoregulation during hyperventilation. Cerebral autoregulation indices (ARI, Mx) were associated with each other.
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Affiliation(s)
- Yi Zhang
- Department of Neurosurgery, University of Cambridge, Cambridge, UK.
- Department of Neurology, University of Rochester Medical Center, 601 Elmwood Avenue, 673, Rochester, NY, 14642, USA.
- Department of Neurology, Saint Louis University, Saint Louis, MO, USA.
| | - Xiuyun Liu
- Department of Neurosurgery, University of Cambridge, Cambridge, UK
| | - Luzius Steiner
- Department of Neurosurgery, University of Cambridge, Cambridge, UK
- Department of Anesthesiology, University Hospital in Basel, Basel, Switzerland
| | - Peter Smielewski
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Eli Feen
- Department of Neurology, Saint Louis University, Saint Louis, MO, USA
| | - John D Pickard
- Department of Neurosurgery, University of Cambridge, Cambridge, UK
| | - Marek Czosnyka
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
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Małowidzka-Serwińska M, Żabicka M, Witkowski A, Chmielak Z, Deptuch T. Brain perfusion evaluated by perfusion-weighted magnetic resonance imaging before and after stenting internal carotid artery stenosis in asymptomatic and symptomatic patients. Neurol Neurochir Pol 2015; 49:412-20. [PMID: 26652876 DOI: 10.1016/j.pjnns.2015.10.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 07/31/2015] [Accepted: 10/12/2015] [Indexed: 10/22/2022]
Abstract
PURPOSE To evaluate the brain perfusion with MRI perfusion weighted imaging (PWI) before and after ICA stenting in asymptomatic and symptomatic patients. MATERIALS AND METHODS PWI was performed 3-21 days before and 3 days after ICA stenting in 31 asymptomatic patients with ICA >70% stenosis - Group I, and in 14 symptomatic patients with ICA >50% stenosis - Group II. PWI was evaluated qualitatively and quantitatively in 5 cerebral territories with: mean transit time (MTT), cerebral blood volume (CBV) and cerebral blood flow (CBF). Mean values of perfusion parameters were measured before and after stenting ΔMTT, ΔCBV, ΔCBF were calculated as subtraction of after-treatment values from those before treatment. RESULTS In qualitative evaluation after ICA stenting perfusion was normalized in 21 patients (80.8%) in Group I and in 8 patients (80%) in Group II. In quantitative estimation MTT decreased significantly after CAS on stented side vs. non-stented side in all examined patients regardless of the group, p<0.05. MTT decreased more in Group II than in Group I in all territories (p<0.05) with the exception of temporal lobe. CBV and CBF have shown insignificant differences.
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Affiliation(s)
| | - Magdalena Żabicka
- Department of Radiology, Military Institute of Medicine, Warsaw, Poland
| | - Adam Witkowski
- Department of Interventional Cardiology and Angiology, Institute of Cardiology, Warsaw, Poland
| | - Zbigniew Chmielak
- Department of Interventional Cardiology and Angiology, Institute of Cardiology, Warsaw, Poland
| | - Tomasz Deptuch
- Department of Interventional Cardiology and Angiology, Institute of Cardiology, Warsaw, Poland
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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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Donnelly J, Aries MJ, Czosnyka M. Further understanding of cerebral autoregulation at the bedside: possible implications for future therapy. Expert Rev Neurother 2015; 15:169-85. [PMID: 25614952 DOI: 10.1586/14737175.2015.996552] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cerebral autoregulation reflects the ability of the brain to keep the cerebral blood flow (CBF) relatively constant despite changes in cerebral perfusion pressure. It is an intrinsic neuroprotective physiological phenomenon often suggested as part of pathophysiological pathways in brain research. However, despite increasing knowledge of this phenomenon for over 50 years, harnessing cerebral autoregulation as a basis for therapy remains an elegant concept rather than a practical reality. This raises the question is it useful to measure at the bedside or is it merely a scientific curiosity that is too complex and has little pragmatic relevance. In this article, we attempt to answer this question by demonstrating how cerebral autoregulation assessment can have prognostic value, indicate pathological states, and potentially even influence therapy with the use of the 'optimal cerebral perfusion pressure' paradigm. Evidence from the literature is combined with bedside clinical examples to address the following fundamental questions about cerebral autoregulation: What is it? How do we measure it? Why is it important? Can we use it as a basis for therapy?
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Affiliation(s)
- Joseph Donnelly
- Department of Clinical Neurosciences, Division of Neurosurgery, Addenbrooke's Hospital, University of Cambridge, Hills Road, Cambridge, CB2 0QQ, UK
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Müller MWD, Osterreich M. A comparison of dynamic cerebral autoregulation across changes in cerebral blood flow velocity for 200 s. Front Physiol 2014; 5:327. [PMID: 25206340 PMCID: PMC4144203 DOI: 10.3389/fphys.2014.00327] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 08/07/2014] [Indexed: 11/18/2022] Open
Abstract
Objectives: The dynamic interaction between blood pressure (BP) and cerebral blood flow velocity (CBFV) is not fully understood, especially for CBFV changes lasting longer than 50 s. The interaction between BP and CBFV is relatively well characterized for periods <50 s using transfer function (TF) estimations of phase, gain, and coherence. We used TF estimations to compare the phase and gain for periods >50 s with those for periods <50 s. Materials and Methods: BP and CBFV (of the middle cerebral artery) were simultaneously recorded in 23 healthy subjects (10 men, 13 women, mean age 35 ± 10 years) under normo- and hypocapnia (induced by hyperventilation). TF and coherence estimations were based on Welch's periodogram method with a windowing of 200 s (frequency resolution, 0.005 Hz, corresponding to a period of 200 s). Means of the phase, gain, and coherence were calculated over frequency periods of 0.005–0.02 Hz (sVLF), 0.02–0.07 Hz (VLF), 0.07–0.15 Hz (LF), and 0.15–0.40 Hz (HF) and analyzed using the t-test and Pearson correlation. Results: Compared with the VLF range, normo- and hypocapnia phases were slightly but significantly lower in sVLF, while gain and coherence were not different. Hypocapnia induced significant (mostly p < 0.01) phase increases and gain decreases as well as coherence decreases in all frequency ranges. The phase and gain correlated significantly (−0.87 < r > −0.99) (p < 0.001) and inversely in all frequency ranges <0.15 Hz under both respiratory conditions. In some instances, the phase indicated disturbed autoregulation. Conclusion: In the frequency range <0.15 Hz, the phase and gain correlate highly and linearly with high consistency. The phase, gain, and coherence were similar in sVLF and VLF ranges. The phase was slightly lower in the sVLF range than in the VLF range. Notably, the data suggest that autoregulatory failure may occur in healthy persons.
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Affiliation(s)
- Martin W-D Müller
- Neurovascular Lab, Department of Neurology and Neurorehabilitation, Kantonsspital Lucerne Lucerne, Switzerland
| | - Mareike Osterreich
- Neurovascular Lab, Department of Neurology and Neurorehabilitation, Kantonsspital Lucerne Lucerne, Switzerland
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Transfer function analysis for the assessment of cerebral autoregulation using spontaneous oscillations in blood pressure and cerebral blood flow. Med Eng Phys 2014; 36:563-75. [DOI: 10.1016/j.medengphy.2014.02.001] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 01/31/2014] [Accepted: 02/03/2014] [Indexed: 12/21/2022]
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Dynamic cerebral autoregulation is heterogeneous in different subtypes of acute ischemic stroke. PLoS One 2014; 9:e93213. [PMID: 24671155 PMCID: PMC3966889 DOI: 10.1371/journal.pone.0093213] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 03/02/2014] [Indexed: 11/19/2022] Open
Abstract
Background and Purpose Stroke of large-artery atherosclerosis and small-artery occlusion are two main subtypes of stroke according to TOAST classification. The underlying mechanisms of how these two subtypes affect dynamic cerebral autoregulation (dCA) might be heterogeneous, resulting in varied clinical conditions and outcomes. We therefore studied the pattern of dCA in these two subtypes. Methods Forty-one patients with acute unilateral middle cerebral artery (MCA) territory stroke (15 with ipsilateral large-artery atherosclerosis and 26 with small-artery occlusion) and 20 healthy volunteers were enrolled. Non-invasive continuous cerebral blood flow velocity and arterial blood pressure were recorded simultaneously from each subject in supine position using transcranial Doppler on MCA bilaterally and servo-controlled plethysmograph on the middle finger, respectively. Transfer function analysis was applied to derive autoregulatory parameters, gain, phase difference (PD), and slope of step response. Results In the large-artery atherosclerosis group, PD in affected hemisphere was 42.9±18.5 degree, which is significantly lower than the unaffected hemisphere (72.4±29.9 degree, P<0.01), and the healthy group (P<0.01). However, PD is similar in the unaffected hemisphere and healthy group (P>0.1). In the small-artery occlusion group, PD in the affected hemisphere was similar to that in the contralateral hemisphere (33.8±17.9 vs. 32.6±21.1 degree, P>0.1), both sides were significantly lower than the healthy group (all P<0.001).The results of the slope of step response agree with the findings in PD. Conclusions DCA in different subtypes of acute ischemic stroke is heterogeneous, which might be attributed to the varied pathologic changes of cerebral blood vessels.
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Heyer EJ, Mergeche JL, Anastasian ZH, Kim M, Mallon KA, Connolly ES. Arterial blood pressure management during carotid endarterectomy and early cognitive dysfunction. Neurosurgery 2014; 74:245-51; discussion 251-3. [PMID: 24335822 PMCID: PMC4038378 DOI: 10.1227/neu.0000000000000256] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND A common practice during cross-clamp of carotid endarterectomy (CEA) is to manage mean arterial pressure (MAP) above baseline to optimize the collateral cerebral blood flow and reduce the risk of ischemic stroke. OBJECTIVE To determine whether MAP management ≥20% above baseline during cross-clamp is associated with lower risk of early cognitive dysfunction, a subtler form of neurological injury than stroke. METHODS One hundred eighty-three patients undergoing CEA were enrolled in this ad hoc study. All patients had radial arterial catheters placed before the induction of general anesthesia. MAP was managed at the discretion of the anesthesiologist. All patients were evaluated with a battery of neuropsychometric tests preoperatively and 24 hours postoperatively. RESULTS Overall, 28.4% of CEA patients exhibited early cognitive dysfunction (eCD). Significantly fewer patients with MAP ≥20% above baseline during cross-clamp exhibited eCD than those managed <20% above (11.6% vs 38.6%, P < .001). In a multivariate logistic regression model, MAP ≥20% above baseline during the cross-clamp period was associated with significantly lower risk of eCD (odds ratio [OR], 0.18 [0.07-0.40], P < .001), whereas diabetes mellitus (OR, 2.73 [1.14-6.61], P = .03) and each additional year of education (OR, 1.19 [1.06-1.34], P = .003) were associated with significantly higher risk of eCD. CONCLUSION The observations of this study suggest that MAP management ≥20% above baseline during cross-clamp of the carotid artery may be associated with lower risk of eCD after CEA. More prospective work is necessary to determine whether MAP ≥20% above baseline during cross-clamp can improve the safety of this commonly performed procedure.
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Affiliation(s)
- Eric J. Heyer
- Department of Anesthesiology, Columbia University, New York, NY
- Department of Neurology, Columbia University, New York, NY
| | | | | | - Minjae Kim
- Department of Anesthesiology, Columbia University, New York, NY
| | | | - E. Sander Connolly
- Department of Neurology, Columbia University, New York, NY
- Department of Neurological Surgery, Columbia University, New York, NY
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Impaired dynamic cerebral autoregulation and cerebrovascular reactivity in middle cerebral artery stenosis. PLoS One 2014; 9:e88232. [PMID: 24505442 PMCID: PMC3913771 DOI: 10.1371/journal.pone.0088232] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2013] [Accepted: 01/04/2014] [Indexed: 11/24/2022] Open
Abstract
Purpose We sought to investigate the capacity of cerebral autoregulation and cerebrovascular reactivity (CVR) in patients with middle cerebral artery (MCA) stenosis. Methods Twenty-one patients with MCA stenosis diagnosed by magnetic resonance angiography and 15 healthy controls were enrolled. Cerebral autoregulation was assessed by autoregulatory parameters (rate of recovery/phase/gain) derived from transfer function from spontaneous oscillations of cerebral blood flow velocity and blood pressure. CVR was tested by a rebreathing maneuver. Results Rate of recovery, phase and CVR estimated from moderate MCA stenosis (rate of recovery = 17.76±8.21%/s, phase = 26.93±15.67°, and CVR = 1.53±0.84%/mmHg, respectively) were significantly different (p<0.05) from controls (rate of recovery = 39.62±27.99%/s, phase = 55.66±22.10°, and CVR = 2.18±0.80%/mmHg, respectively). Rate of recovery (r = −0.698, p<0.001), phase (r = −0.738, p<0.001)) and CVR (r = −0.690, p<0.001) were all significantly correlated with the degree of stenosis. Conclusion Cerebral autoregulation and CVR were impaired in patients with ≥ 50% MCA stenosis. The measures of both hemodynamic properties were inversely correlated with the stenotic degree.
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Cross TJ, Kavanagh JJ, Breskovic T, Johnson BD, Dujic Z. Dynamic cerebral autoregulation is acutely impaired during maximal apnoea in trained divers. PLoS One 2014; 9:e87598. [PMID: 24498340 PMCID: PMC3911978 DOI: 10.1371/journal.pone.0087598] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 12/21/2013] [Indexed: 11/22/2022] Open
Abstract
Aims To examine whether dynamic cerebral autoregulation is acutely impaired during maximal voluntary apnoea in trained divers. Methods Mean arterial pressure (MAP), cerebral blood flow-velocity (CBFV) and end-tidal partial pressures of O2 and CO2 (PETO2 and PETCO2) were measured in eleven trained, male apnoea divers (28±2 yr; 182±2 cm, 76±7 kg) during maximal “dry” breath holding. Dynamic cerebral autoregulation was assessed by determining the strength of phase synchronisation between MAP and CBFV during maximal apnoea. Results The strength of phase synchronisation between MAP and CBFV increased from rest until the end of maximal voluntary apnoea (P<0.05), suggesting that dynamic cerebral autoregulation had weakened by the apnoea breakpoint. The magnitude of impairment in dynamic cerebral autoregulation was strongly, and positively related to the rise in PETCO2 observed during maximal breath holding (R2 = 0.67, P<0.05). Interestingly, the impairment in dynamic cerebral autoregulation was not related to the fall in PETO2 induced by apnoea (R2 = 0.01, P = 0.75). Conclusions This study is the first to report that dynamic cerebral autoregulation is acutely impaired in trained divers performing maximal voluntary apnoea. Furthermore, our data suggest that the impaired autoregulatory response is related to the change in PETCO2, but not PETO2, during maximal apnoea in trained divers.
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Affiliation(s)
- Troy J. Cross
- Griffith Health Institute and Heart Foundation Research Centre, Griffith University, Gold Coast Campus, Queensland, Australia
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
- * E-mail:
| | - Justin J. Kavanagh
- Griffith Health Institute and Heart Foundation Research Centre, Griffith University, Gold Coast Campus, Queensland, Australia
| | - Toni Breskovic
- Department of Physiology, University of Split School of Medicine, Split, Croatia
| | - Bruce D. Johnson
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Zeljko Dujic
- Department of Physiology, University of Split School of Medicine, Split, Croatia
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Xu G, Liu X, Meyer JS, Yin Q, Zhang R. Cognitive performance after carotid angioplasty and stenting with brain protection devices. Neurol Res 2013; 29:251-5. [PMID: 17178010 DOI: 10.1179/016164107x159216] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
OBJECTIVE Neuropsychological outcomes after carotid endarterectomy (CEA) have been investigated extensively. However, cognitive impacts of carotid angioplasty and stenting (CAS), an emerging alternative to CEA, have not been studied. This study is aimed at investigating pattern and degree of cognitive changes after CAS among patients with high-grade carotid stenosis. PATIENTS AND METHODS Fifty-four patients with high-grade carotid artery stenosis and received elective CAS were followed. Sixty-six patients with similar medical conditions requiring carotid angiography (CAG) were enrolled as controls. Cognitive functions among patients in both groups were evaluated at baseline and follow-ups utilizing a battery of neuropsychometric tests. Results were analysed by inter-group and within-group comparisons. RESULTS There were no statistically significant differences between CAS and CAG patients regarding demographic characteristics, risk factors for stroke and baseline cognitive performance (p>0.05). CAS patients performed significantly better than CAG patients in Rey auditory verbal learning tests (RAVLT) at week 1 (41.2 +/- 5.2 versus 37.4 +/- 4.0, p<0.001) and week 12 follow-ups (43.3 +/- 7.7 versus 37.3 +/- 4.5, p<0.001). Comparison of z score also indicated CAS patients improved significantly more than CAG patients in RAVLT at both weeks 1 (1.08 +/- 1.29 versus 0.25 +/- 0.99, p<0.001) and 12 follow-ups (1.62 +/- 1.95 versus 0.05 +/- 1.02, p<0.001). CONCLUSION CAS patients demonstrated improvement in verbal memory after procedures. Correction of cerebral hypoperfusion and reduction of artery-to-artery embolization after CAS are postulated responsible for the cognitive improvement.
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Affiliation(s)
- Gelin Xu
- Department of Neurology, Jinling Hospital, Nanjing University School of Medicine, Nanjing, Jiangsu, China.
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Variability of the autoregulation index decreases after removing the effect of the very low frequency band. Med Eng Phys 2013; 36:601-6. [PMID: 24238618 DOI: 10.1016/j.medengphy.2013.10.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 10/02/2013] [Accepted: 10/13/2013] [Indexed: 11/20/2022]
Abstract
Dynamic cerebral autoregulation (dCA) estimates show large between and within subject variability. Sources of variability include low coherence and influence of CO2 in the very low frequency (VLF) band, where dCA is active. This may lead to unreliable transfer function and autoregulation index (ARI) estimates. We tested whether variability of the ARI could be decreased by suppressing the effect of the VLF band through filtering. We also evaluated whether filtering had any effect on mean group differences between healthy subjects and acute stroke patients. Data from a recent mobilization stroke study were re-analyzed. Middle cerebral artery cerebral blood flow velocity (MCA-CBFV), mean arterial blood pressure (MABP) and end tidal PCO2 (PetCO2) were obtained in 16 healthy subjects and 27 acute ischemic stroke patients in the supine position. The ARI index was calculated from the transfer function (TF) by using spontaneous BP fluctuations. Three different filtering strategies were compared; no filtering (NF), a high pass filter at 0.04 Hz (Time Domain Filtering: TDF) and a high pass Transfer Function Filter (TFF) at 0.04 Hz. In addition, a simulation study was done to obtain further insight into the effects of the applied filters. The variability of the ARI index decreased significantly only with TFF in healthy subjects (standard deviation (left vs. right) after NF 2.28 vs. 2.36, after TDF 2.13 vs. 2.31 after TFF 1.09 vs. 1.19, p<0.001). Variability was not significantly reduced in stroke patients. The mean ARI was significantly lower in stroke patients compared to healthy subjects after TFF (affected hemisphere 5.85±1.96 vs. 7.13±1.09, non-affected hemisphere 5.96±1.64 vs. 7.31±1.19, p<0.01 for both hemispheres), but not after NF or TDF. The simulation study showed that TFF results in an overestimation of the ARI index at low ARI levels (0-3), but in correct estimates at higher ARI levels. Removing the effect of the VLF band with TFF results in less ARI variability in healthy subjects, and in more pronounced group differences between stroke patients and healthy subjects. This will improve diagnostic properties when using TFA for ARI calculation.
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Blaine Easley R, Kibler KK, Brady KM, Joshi B, Ono M, Brown C, Hogue CW. Continuous cerebrovascular reactivity monitoring and autoregulation monitoring identify similar lower limits of autoregulation in patients undergoing cardiopulmonary bypass. Neurol Res 2013; 35:344-54. [PMID: 23540403 DOI: 10.1179/1743132812y.0000000145] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
OBJECTIVES Cerebrovascular autoregulation can be monitored with a moving linear correlation of blood pressure to cerebral blood flow velocity (mean velocity index, Mx) during cardiopulmonary bypass (CPB). Vascular reactivity can be monitored with a moving linear correlation of blood pressure to cerebral blood volume trended with near-infrared spectroscopy (hemoglobin volume index, HVx). We hypothesized that the lower limits of autoregulation (LLA) and the optimal blood pressure (ABPopt) associated with the most active autoregulation could be determined by HVx in patients undergoing CPB. METHODS Adult patients (n = 109) who underwent CPB for cardiac surgery had monitoring of both autoregulation (Mx) and vascular reactivity (HVx). Individual curves of Mx and HVx were constructed by placing each in 5 mmHg bins. The LLA and ABPopt for each subject were then identified by both methods and compared for agreement by correlation analysis and Bland-Altman. RESULTS The average LLA defined by Mx compared to HVx were comparable (66±13 and 66±12 mmHg). Correlation between the LLA defined by Mx and HVx was significant (Pearson r = 0.2867; P = 0.0068). The average ABPopt with the most robust autoregulation by Mx was comparable to HVx (75±11 and 74±13 mmHg) with significant correlation (Pearson r = 0.5915; P < or =0.0001). DISCUSSION Autoregulation and vascular reactivity monitoring are expected to be distinct, as flow and volume have different phasic relationships to pressure when cerebrovascular autoregulation is active. However, the two metrics have good agreement when identifying the LLA and optimal blood pressure in patients during CPB.
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Affiliation(s)
- R Blaine Easley
- Baylor College of Medicine, Texas Children's Hospital, Houston, TX 77030, USA.
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Heyer EJ, Mergeche JL, Connolly ES. Middle cerebral artery pulsatility index and cognitive improvement after carotid endarterectomy for symptomatic stenosis. J Neurosurg 2013; 120:126-31. [PMID: 24010976 DOI: 10.3171/2013.8.jns13931] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT Transcranial Doppler (TCD) is frequently used to evaluate peripheral cerebral resistance and cerebral blood flow (CBF) in the middle cerebral artery prior to and during carotid endarterectomy (CEA). Patients with symptomatic carotid artery stenosis may have reduced peripheral cerebral resistance to compensate for inadequate CBF. The authors aim to determine whether symptomatic patients with reduced peripheral cerebral resistance prior to CEA demonstrate increased CBF and cognitive improvement as early as 1 day after CEA. METHODS Fifty-three patients with symptomatic CEA were included in this observational study. All patients underwent neuropsychometric evaluation 24 hours or less preoperatively and 1 day postoperatively. The MCA was evaluated using TCD for CBF mean velocity (MV) and pulsatility index (PI). Pulsatility index ≤ 0.80 was used as a cutoff for reduced peripheral cerebral resistance. RESULTS Significantly more patients with baseline PI ≤ 0.80 exhibited cognitive improvement 1 day after CEA than those with PI > 0.80 (35.0% vs 6.1%, p = 0.007). Patients with cognitive improvement had a significantly greater increase in CBF MV than patients without cognitive improvement (13.4 ± 17.1 cm/sec vs 4.3 ± 9.9 cm/sec, p = 0.03). In multivariate regression model, a baseline PI ≤ 0.80 was significantly associated with increased odds of cognitive improvement (OR 7.32 [1.40-59.49], p = 0.02). CONCLUSIONS Symptomatic CEA patients with reduced peripheral cerebral resistance, measured as PI ≤ 0.80, are likely to have increased CBF and improved cognitive performance as early as 1 day after CEA for symptomatic carotid artery stenosis. Revascularization in this cohort may afford benefits beyond prevention of future stroke. Clinical trial registration no: NCT00597883 ( ClinicalTrials.gov ).
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Gong XP, Li Y, Jiang WJ, Wang Y. Impaired dynamic cerebral autoregulation in middle cerebral artery stenosis. Neurol Res 2013; 28:76-81. [PMID: 16464367 DOI: 10.1179/016164106x91915] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
BACKGROUND AND PURPOSE Analysis of dynamic cerebral autoregulation during transient falls in blood pressure is considered a sensitive and convenient method for evaluating patients with carotid artery stenosis. To this point, there have been few reports on the efficacy of using the thigh cuffs technique to analyse middle cerebral artery (MCA) stenosis. If it could be determined whether cerebral blood flow can be maintained (autoregulated) during sudden falls in arterial blood pressure (ABP), then it might be possible to identify patients with MCA stenosis who are at risk of stroke. METHODS We used the thigh cuff technique to estimate dynamic cerebral autoregulation in 57 patients with MCA stenosis and 72 normal controls. After a stepwise fall in arterial blood pressure, we determined the rate of the rise of MCA blood velocity and compared it with the rate of the rise of arterial blood pressure. In this manner, the dynamic cerebral autoregulation of 11 patients undergoing MCA M1 stent angioplasty was estimated both pre- and post-operation. RESULTS The autoregulatory index (ARI) was significantly reduced in patients with stenosed/occluded MCA (3.24 +/- 1.52), as compared with normal controls (5.25 +/- 1.39; p<0.001) (results reported as mean +/- SD). Poor ARI values are usually observed in patients with a higher degree of stenosis and particularly in patients with insufficient collateral compensation. ARI was significantly reduced in severe stroke patients (modified ranking scale>or=1), as compared with asymptomatic or TIA patients (p<0.05). After MCA stent angioplasty was performed, there was a significant improvement in ARI in 11 subjects, which caused a mean increase in ARI from 2.08 +/- 1.10 to 3.80 +/- 1.36 (p=0.008). CONCLUSIONS Dynamic cerebral autoregulation is impaired in patients with middle cerebral artery stenosis. Assessing dynamic cerebral autoregulation may allow a subgroup of patients with MCA stenosis who are at risk of hemodynamic stroke to be identified. Dynamic cerebral disautoregulation in patients with severe MCA stenosis is mostly remedied by stent angioplasty.
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Affiliation(s)
- Xi-ping Gong
- Department of Neurology, Beijing Tiantan Hospital, Capital University of Medical Sciences, Beijing, China
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Youn SW, Kim HK, Do YR, Do JK, Kwon OC, Lee N, Lee HJ, Lee J. Haemodynamic alterations in cerebral blood vessels after carotid artery revascularisation: quantitative analysis using 2D phase-contrast MRI. Eur Radiol 2013; 23:2880-90. [PMID: 23732686 DOI: 10.1007/s00330-013-2899-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2013] [Revised: 04/03/2013] [Accepted: 04/09/2013] [Indexed: 11/25/2022]
Abstract
OBJECTIVES This study was conducted to evaluate the effect of revascularisation, whether revascularisation improves total cerebral blood flow volume (FVTCBF), and how cerebral veins would respond to altered FVTCBF. METHODS The 39 carotid artery stenoses in 37 patients who underwent revascularisation including 32 stentings and 7 endarterectomies were included in this prospective study. From the two-dimensional phase-contrast (2D-PC) MRI acquired before and after revascularisation, the flow volumes (FVs) of the arteries and veins were compared using paired t-test. The relationships between these parameters were correlated using Pearson's correlation coefficient. RESULTS The mean FV in the treated carotid artery (proportion of treated artery among total FV) increased from 162.06 ml/min (25.80 %) to 267.71 ml/min (37.21 %; P < 0.001). Revascularisation increased the FVTCBF of patients from 638.66 ml/min to 716.72 ml/min (P < 0.001). The FV of the internal jugular veins, superior sagittal and straight sinuses (FVSS + SSS), and transverse sinuses increased after revascularisation (P < 0.05). Positive relationships were shown between the FVTCBF and the FVSS + SSS (r = 0.584-0.741, P < 0.001). CONCLUSIONS Revascularisation improves the FVTCBF by increasing the FV in the treated carotid artery. The venous drainages are closely linked to FVTCBF. 2D-PC-MRI is a feasible method for evaluating comprehensively the haemodynamic improvement after revascularisation. KEY POINTS • Revascularisation may be beneficial in ischaemic strokes due to carotid artery stenosis. • Revascularisation of the affected artery increases total cerebral blood flow volume ( FV TCBF). • Cerebral venous drainage, closely linked to FV TCBF, is also improved. • Two-dimensional phase-contrast MRI can comprehensively assess these haemodynamic improvements after carotid revascularisation.
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Affiliation(s)
- Sung Won Youn
- Department of Radiology, Catholic University of Daegu School of Medicine, 3056-6 Daemyung-4 Dong, Nam-Gu, Daegu, 705-718, Korea,
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Shin JW, Jeong HS, Song HJ, Lee JH, Choi SW, Lee SH, Shin J, Kim J. Intracranial Hemodynamic Stabilization Patterns After Stenting of Severe Stenosis in the Proximal Internal Carotid Artery. J Endovasc Ther 2013; 20:398-405. [DOI: 10.1583/12-4172mr.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Neurocognitive changes after eversion carotid endarterectomy under local anesthesia. Ann Vasc Surg 2013; 27:727-35. [PMID: 23706182 DOI: 10.1016/j.avsg.2012.06.029] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Revised: 05/07/2012] [Accepted: 06/12/2012] [Indexed: 11/20/2022]
Abstract
BACKGROUND The effects of carotid endarterectomy (CEA) on cognitive function have yet to be fully elucidated. The aim of our study was to administer a battery of cognitive tests to identify any cognitive changes occurring in a consecutive series of patients who underwent CEA using the eversion technique under local anesthesia. METHODS This prospective study was designed to analyze a consecutive series of patients undergoing eversion CEA under local anesthesia for significant carotid stenosis at our vascular surgery unit over a period of 6 months. Patients underwent tests to rule-out those who already had cognitive impairments or states of depression/anxiety capable of interfering with cognitive testing outcomes. Patients then completed a battery of 10 neurocognitive tests preoperatively and again 30 days and 4 months after surgery to assess the functions of both cerebral hemispheres as thoroughly as possible. RESULTS Of the 48 patients initially considered for our study, 39 completed the follow-up. They were 71.4 ± 8.2 (mean ± SD) years of age; 30 were men and 9 were women. Six were symptomatic for carotid stenosis and 33 were asymptomatic. All patients were examined by a neurologist and underwent pre- and postoperative nuclear MRI or CT scan of the brain to identify any cerebral ischemia potentially correlated with the surgical procedure. In all cases, the cognitive test findings tended to improve postoperatively; this improvement was statistically significant in 7 tests. Post-hoc analysis confirmed an improvement between the pre- and postoperative test results. Among the different variables considered, only age <75 years seems to have influenced cognitive improvement. CONCLUSIONS The effects on cognitive function of carotid stenosis, particularly CEA, is still a much debated issue. The data reported in the literature vary considerably, preventing any final conclusions from being drawn. The mechanisms capable of inducing changes in cognitive status after CEA have yet to be precisely clarified. In our study, a suitable battery of tests were used to analyze the trend of cognitive function correlating with eversion CEA under local anesthesia. Our results demonstrate substantially improved cognitive function after CEA, which was statistically significant in 7 of 10 tests. We surmise that the CEA procedure, per se, can help to protect patients against cognitive deterioration, especially in those <75 years of age.
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Budohoski KP, Reinhard M, Aries MJH, Czosnyka Z, Smielewski P, Pickard JD, Kirkpatrick PJ, Czosnyka M. Monitoring cerebral autoregulation after head injury. Which component of transcranial Doppler flow velocity is optimal? Neurocrit Care 2013; 17:211-8. [PMID: 21691895 DOI: 10.1007/s12028-011-9572-1] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Cerebral autoregulation assessed using transcranial Doppler (TCD) mean flow velocity (FV) in response to various physiological challenges is predictive of outcome after traumatic brain injury (TBI). Systolic and diastolic FV have been explored in other diseases. This study aims to evaluate the systolic, mean and diastolic FV for monitoring autoregulation and predicting outcome after TBI. METHODS 300 head-injured patients with blood pressure (ABP), intracranial pressure (ICP), cerebral perfusion pressure (CPP), and FV recordings were studied. Autoregulation was calculated as a correlation of slow changes in diastolic, mean and systolic components of FV with CPP (Dx, Mx, Sx, respectively) and ABP (Dxa, Mxa, Sxa, respectively) from 30 consecutive 10 s averaged values. The relationship with age, severity of injury, and dichotomized 6 months outcome was examined. RESULTS Association with outcome was significant for Mx and Sx. For favorable/unfavorable and death/survival outcomes Sx showed the strongest association (F = 20.11; P = 0.00001 and F = 13.10; P = 0.0003, respectively). Similarly, indices derived from ABP demonstrated the highest discriminatory value when systolic FV was used (F = 12.49; P = 0.0005 and F = 5.32; P = 0.02, respectively). Indices derived from diastolic FV demonstrated significant differences (when calculated using CPP) only when comparing between fatal and non-fatal outcome. CONCLUSIONS Systolic flow indices (Sx and Sxa) demonstrated a stronger association with outcome than the mean flow indices (Mx and Mxa), irrespective of whether CPP or ABP was used for calculation.
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Affiliation(s)
- Karol P Budohoski
- Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Hills Road, Cambridge CB2 0QQ, UK.
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Ono M, Zheng Y, Joshi B, Sigl JC, Hogue CW. Validation of a stand-alone near-infrared spectroscopy system for monitoring cerebral autoregulation during cardiac surgery. Anesth Analg 2012; 116:198-204. [PMID: 23223100 DOI: 10.1213/ane.0b013e318271fb10] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Individualizing arterial blood pressure (ABP) targets during cardiopulmonary bypass (CPB) based on cerebral blood flow (CBF) autoregulation monitoring may provide a more effective means for preventing cerebral hypoperfusion than the current standard of care. Autoregulation can be monitored in real time with transcranial Doppler (TCD). We have previously demonstrated that near-infrared spectroscopy (NIRS)-derived regional cerebral oxygen saturation (rS(c)O(2)) provides a clinically suitable surrogate of CBF for autoregulation monitoring. The purpose of this study was to determine the accuracy of a stand-alone "plug-and-play" investigational system for autoregulation monitoring that uses a commercially available NIRS monitor with TCD methods. METHODS TCD monitoring of middle cerebral artery CBF velocity and NIRS monitoring were performed in 70 patients during CPB. Indices of autoregulation were computed by both a personal computer-based system and an investigational prototype NIRS-based monitor. A moving linear correlation coefficient between slow waves of ABP and CBF velocity (mean velocity index [Mx]) and between ABP and rS(c)O(2) (cerebral oximetry index [COx]) were calculated. When CBF is autoregulated, there is no correlation between CBF and ABP; when CBF is dysregulated, Mx and COx approach 1 (i.e., CBF and ABP are correlated). Linear regression and bias analysis were performed between time-averaged values of Mx and COx derived from the personal computer-based system and from COx measured with the prototype monitor. Values for Mx and COx were categorized in 5 mm Hg bins of ABP for each patient. The lower limit of CBF autoregulation was defined as the ABP where Mx incrementally increased to ≥0.4. RESULTS There was correlation and good agreement between COx derived from the prototype monitor and Mx (r = 0.510; 95% confidence interval, 0.414-0.595; P < 0.001; bias, -0.07 ± 0.19). The correlation and bias between the personal computer-based COx and the COx from the prototype NIRS monitor were r = 0.957 (95% confidence interval, 0.945-0.966; P < 0.001 and 0.06 ± 0.06, respectively). The average ABP at the lower limit of autoregulation was 63 ± 11 mm Hg (95% prediction interval, 52-74 mm Hg). Although the mean ABP at the COx-determined lower limit of autoregulation determined with the prototype monitor was statistically different from that determined by Mx (59 ± 9 mm Hg; 95% prediction interval, 50-68 mm Hg; P = 0.026), the difference was not likely clinically meaningful. CONCLUSIONS Monitoring CBF autoregulation with an investigational stand-alone NIRS monitor is correlated and in good agreement with TCD-based methods. The availability of such a device would allow widespread autoregulation monitoring as a means of individualizing ABP targets during CPB.
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Affiliation(s)
- Masahiro Ono
- Division of Cardiac Surgery, Department of Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
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Cardiovascular risk factors promote brain hypoperfusion leading to cognitive decline and dementia. Cardiovasc Psychiatry Neurol 2012; 2012:367516. [PMID: 23243502 PMCID: PMC3518077 DOI: 10.1155/2012/367516] [Citation(s) in RCA: 270] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Accepted: 10/30/2012] [Indexed: 11/18/2022] Open
Abstract
Heart disease is the major leading cause of death and disability in the world. Mainly affecting the elderly population, heart disease and its main outcome, cardiovascular disease, have become an important risk factor in the development of cognitive decline and Alzheimer's disease (AD). This paper examines the evidence linking chronic brain hypoperfusion induced by a variety of cardiovascular deficits in the development of cognitive impairment preceding AD. The evidence indicates a strong association between AD and cardiovascular risk factors, including ApoE(4), atrial fibrillation, thrombotic events, hypertension, hypotension, heart failure, high serum markers of inflammation, coronary artery disease, low cardiac index, and valvular pathology. In elderly people whose cerebral perfusion is already diminished by their advanced age, additional reduction of cerebral blood flow stemming from abnormalities in the heart-brain vascular loop ostensibly increases the probability of developing AD. Evidence also suggests that a neuronal energy crisis brought on by relentless brain hypoperfusion may be responsible for protein synthesis abnormalities that later result in the classic neurodegenerative lesions involving the formation of amyloid-beta plaques and neurofibrillary tangles. Insight into how cardiovascular risk factors can induce progressive cognitive impairment offers an enhanced understanding of the multifactorial pathophysiology characterizing AD and ways at preventing or managing the cardiovascular precursors of this dementia.
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Phillip D, Schytz HW, Selb J, Payne S, Iversen HK, Skovgaard LT, Boas DA, Ashina M. Low frequency oscillations in cephalic vessels assessed by near infrared spectroscopy. Eur J Clin Invest 2012; 42:1180-8. [PMID: 22897146 PMCID: PMC3730271 DOI: 10.1111/j.1365-2362.2012.02704.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND AND METHODS Low frequency oscillations (LFO) of cerebral vessels are believed to reflect cerebral autoregulation. We investigated day-to-day and hemispheric variations in 0.1 Hz LFO with near infrared spectroscopy (NIRS) and transcranial Doppler (TCD) to determine phase shift and gain of oxygenated haemoglobin (oxyHb) and the velocity of the middle cerebral artery (Vmca) to the arterial blood pressure (ABP). The direct left-right phase shifts of oxyHb and Vmca were also assessed. We examined 44 healthy volunteers by simultaneous recordings of ABP, oxyHb and Vmca during spontaneous and paced breathing at 6 breaths per minute on two separate days. RESULTS The variation between hemispheres had a prediction interval (PI) of ± 39° for ABP-oxyHb phase shift and ± 69% for gain. ABP-Vmca showed ± 57° PI phase shift and ± 158% PI for gain. The variation from day to day showed ± 61° PI for ABP-oxyHb phase shift and ± 297% PI for gain. ABP-Vmca showed ± 45° PI phase shift and ± 166% PI for gain. We found a linear relation between phase shift of oxyHb and Vmca at paced breathing (P=0.0005), but not at rest (P=0.235). CONCLUSION Our results show that LFO phase shift ABP-oxyHb may be used as a robust measurement of differences in autoregulation between hemispheres and over time. In addition, we found a strong relation between oxyHb and Vmca during paced breathing. Gain showed too large variation for clinical use, as the SD was up to 100-fold of mean values.
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Affiliation(s)
- Dorte Phillip
- Danish Headache Center, Glostrup Hospital, University of Copenhagen, Copenhagen, Denmark
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Haubrich C, Steiner L, Kim DJ, Kasprowicz M, Smielewski P, Diehl RR, Pickard JD, Czosnyka M. How does moderate hypocapnia affect cerebral autoregulation in response to changes in perfusion pressure in TBI patients? ACTA NEUROCHIRURGICA. SUPPLEMENT 2012; 114:153-6. [PMID: 22327682 DOI: 10.1007/978-3-7091-0956-4_28] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
In traumatic brain injury, the hypocapnic effects on blood pressure autoregulation may vary from beneficial to detrimental. The consequences of moderate hypocapnia (HC) on the autoregulation of cerebral perfusion pressure (CPP) have not been monitored so far.Thirty head injured patients requiring sedation and mechanical ventilation were studied during normocapnia (5.1 ± 0.4 kPa) and moderate HC (4.4 ± 3.0 kPa). Transcranial Doppler flow velocity (Fv) of the middle cerebral arteries (MCA), invasive arterial blood pressure, and intracranial pressure were monitored. CPP was calculated. The responsiveness of Fv to slow oscillations in CPP was assessed by means of the moving correlation coefficient, the Mx autoregulatory index. Hypocapnic effects on Mx were increasing with its deviation from normal baseline (left MCA: R (2) = 0.67; right MCA: R (2) = 0.51; p < 0.05). Mx indicating normal autoregulation (left: -0.23 ± 0.23; right: -0.21 ± 0.24) was not significantly changed by moderate HC. Impaired Mx autoregulation, however, (left: 0.37 ± 0.13; right: 0.33 ± 0.26) was improved (left: 0.12 ± 0.25; right: -0.0003 ± 0.19; p < 0.01) during moderate HC. Mx was adjusted to normal despite no significant change in CPP levels. Our study showed that short-term moderate HC may optimize the autoregulatory response to spontaneous CPP fluctuations with only a small CPP increase. Patients with impaired autoregulation seemed to benefit the most.
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Affiliation(s)
- Christina Haubrich
- Department of Academic Neurosurgery, Addenbrooke's Hospital, Cambridge, UK.
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Marmarelis VZ, Shin DC, Zhang R. Linear and Nonlinear Modeling of Cerebral Flow Autoregulation Using Principal Dynamic Modes. Open Biomed Eng J 2012. [DOI: 10.2174/1874120701206010042] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cerebral Flow Autoregulation (CFA) is the dynamic process by which cerebral blood flow is maintained within physiologically acceptable bounds during fluctuations of cerebral perfusion pressure. The distinction is made with “static” flow autoregulation under steady-state conditions of perfusion pressure, described by the celebrated “autoregulatory curve” with a homeostatic plateau. This paper studies the dynamic CFA during changes in perfusion pressure, which attains critical clinical importance in patients with stroke, traumatic brain injury and neurodegenerative disease with a cerebrovascular component. Mathematical and computational models have been used to advance our quantitative understanding of dynamic CFA and to elucidate the underlying physiological mechanisms by analyzing the relation between beat-to-beat data of mean arterial blood pressure (viewed as input) and mean cerebral blood flow velocity(viewed as output) of a putative CFA system. Although previous studies have shown that the dynamic CFA process is nonlinear, most modeling studies to date have been linear. It has also been shown that blood CO2 tension affects the CFA process. This paper presents a nonlinear modeling methodology that includes the dynamic effects of CO2 tension (or its surrogate, end-tidal CO2) as a second input and quantifies CFA from short data-records of healthy human subjects by use of the modeling concept of Principal Dynamic Modes (PDMs). The PDMs improve the robustness of the obtained nonlinear models and facilitate their physiological interpretation. The results demonstrate the importance of including the CO2 input in the dynamic CFA study and the utility of nonlinear models under hypercapnic or hypocapnic conditions.
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49
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Marmarelis V, Shin D, Zhang R. Linear and nonlinear modeling of cerebral flow autoregulation using principal dynamic modes. Open Biomed Eng J 2012; 6:42-55. [PMID: 22723806 PMCID: PMC3377891 DOI: 10.2174/1874230001206010042] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Revised: 02/24/2012] [Accepted: 02/25/2012] [Indexed: 12/02/2022] Open
Abstract
Cerebral Flow Autoregulation (CFA) is the dynamic process by which cerebral blood flow is maintained within physiologically acceptable bounds during fluctuations of cerebral perfusion pressure. The distinction is made with “static” flow autoregulation under steady-state conditions of perfusion pressure, described by the celebrated “autoregulatory curve” with a homeostatic plateau. This paper studies the dynamic CFA during changes in perfusion pressure, which attains critical clinical importance in patients with stroke, traumatic brain injury and neurodegenerative disease with a cerebrovascular component. Mathematical and computational models have been used to advance our quantitative understanding of dynamic CFA and to elucidate the underlying physiological mechanisms by analyzing the relation between beat-to-beat data of mean arterial blood pressure (viewed as input) and mean cerebral blood flow velocity(viewed as output) of a putative CFA system. Although previous studies have shown that the dynamic CFA process is nonlinear, most modeling studies to date have been linear. It has also been shown that blood CO2 tension affects the CFA process. This paper presents a nonlinear modeling methodology that includes the dynamic effects of CO2 tension (or its surrogate, end-tidal CO2) as a second input and quantifies CFA from short data-records of healthy human subjects by use of the modeling concept of Principal Dynamic Modes (PDMs). The PDMs improve the robustness of the obtained nonlinear models and facilitate their physiological interpretation. The results demonstrate the importance of including the CO2 input in the dynamic CFA study and the utility of nonlinear models under hypercapnic or hypocapnic conditions.
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Affiliation(s)
- Vz Marmarelis
- Department of Biomedical Engineering and the Biomedical Simulations Resource (BMSR) at the University of Southern California, Los Angeles, CA 90089, USA
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Liang F, Fukasaku K, Liu H, Takagi S. A computational model study of the influence of the anatomy of the circle of willis on cerebral hyperperfusion following carotid artery surgery. Biomed Eng Online 2011; 10:84. [PMID: 21943370 PMCID: PMC3203260 DOI: 10.1186/1475-925x-10-84] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Accepted: 09/23/2011] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Cerebral hyperperfusion syndrome develops in a small subset of patients following carotid artery surgery (CAS) performed to treat severe carotid artery stenosis. This syndrome has been found to have a close correlation with cerebral hyperperfusion occurring after CAS. The purpose of this study is to investigate whether and how the anatomy of the Circle of Willis (CoW) of the cerebral circulation influences post-CAS cerebral hyperperfusion. METHODS A computational model of the cerebral circulation coupled with the global cardiovascular system has been developed to investigate hemodynamic events associated with CAS. Nine topological structures of the CoW were investigated in combination with various distribution patterns of stenosis in the feeding arteries of the cerebral circulation. RESULTS The occurrence of post-CAS cerebral hyperperfusion was predicted for the CoW structures that have poor collateral pathways between the stenosed cerebral feeding arteries and the remaining normal feeding arteries. The risk and the localization of post-CAS hyperperfusion were determined jointly by the anatomy of the CoW and the distribution pattern of stenosis in the cerebral feeding arteries. The presence of basilar artery stenosis or contralateral ICA stenosis increased the risk of post-CAS hyperperfusion and enlarged the cerebral region affected by hyperperfusion. For a certain CoW structure, the diameters of the cerebral communicating arteries and the severity of carotid artery stenosis both had a significant influence on the computed post-CAS cerebral hyperperfusion rates. Moreover, post-CAS cerebral hyperperfusion was predicted to be accompanied with an excessively high capillary transmural pressure. CONCLUSIONS This study demonstrated the importance of considering the anatomy of the CoW in assessing the risk of post-CAS cerebral hyperperfusion. Particularly, since the anatomy of the CoW and the distribution pattern of stenosis in the cerebral feeding arteries jointly determine the risk and localization of post-CAS cerebral hyperperfusion, a patient-specific hemodynamic analysis aimed to help physicians identify patients at high risk of cerebral hyperperfusion should account for the combined effect of the anatomy of cerebral arteries and cerebral feeding artery stenoses on cerebral hemodynamics.
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Affiliation(s)
- Fuyou Liang
- Computational Science Research Program, RIKEN, Wako, Saitama, Japan
| | | | - Hao Liu
- Graduate School of Engineering, Chiba University, Chiba-Shi, Chiba, Japan
| | - Shu Takagi
- Computational Science Research Program, RIKEN, Wako, Saitama, Japan
- Department of Mechanical Engineering, The University of Tokyo, Tokyo, Japan
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