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Cerebrovascular reactivity

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https://www.readbyqxmd.com/read/28931072/high-prevalence-of-non-dipping-blood-pressure-and-vascular-stiffness-in-hiv-infected-south-africans-on-antiretrovirals
#1
M S Borkum, J M Heckmann, K Manning, J A Dave, N S Levitt, B L Rayner, N Wearne
BACKGROUND: HIV-infected individuals are at increased risk of tissue inflammation and accelerated vascular aging ('inflamm-aging'). Abnormal diurnal blood pressure (BP) rhythms such as non-dipping may contribute to an increased risk of cardiovascular and cerebrovascular events in HIV infected individuals. However, little data exists on ambulatory blood pressure (ABP) and measures of vascular stiffness in the black African HIV infected population. METHODS: This is a cross-sectional analysis of otherwise well, HIV infected outpatients on ART for >5 years...
2017: PloS One
https://www.readbyqxmd.com/read/28924565/nirs-based-cerebrovascular-regulation-assessment-exercise-and-cerebrovascular-reactivity
#2
Stephanie Miller, Kunal Mitra
Alterations to cerebral blood flow (CBF) have been implicated in diverse neurological conditions. Near-infrared spectroscopy (NIRS)-measured regional cerebral tissue oxygen saturation ([Formula: see text]) provides an estimate of oxygenation of interrogated cerebral volume useful in identifying variations in oxygen supply to cerebral tissue and in monitoring cerebrovascular function. [Formula: see text]-inhalation-based hypercapnic breathing challenges were used to simulate CBF dysregulation, utilizing NIRS to monitor the CBF autoregulatory response...
October 2017: Neurophotonics
https://www.readbyqxmd.com/read/28918088/evaluation-of-cerebrovascular-reactivity-in-subjects-with-and-without-obstructive-sleep-apnea
#3
Clodagh M Ryan, Anne Battisti-Charbonney, Olivia Sobczyk, David J Mikulis, James Duffin, Joseph A Fisher, Lashmi Venkatraghavan
BACKGROUND: Both obstructive sleep apnea (OSA) and altered cerebrovascular reactivity (CVR) are associated with increased stroke risk. Nevertheless, the incidence of abnormal CVR in patients with OSA is uncertain due to the high variability in the way CVR is measured both within and between studies. We hypothesized that a standardized CVR with a consistent vasoactive stimulus and cerebral blood flow (CBF) measure would be reduced in patients with severe OSA compared with healthy controls...
September 13, 2017: Journal of Stroke and Cerebrovascular Diseases: the Official Journal of National Stroke Association
https://www.readbyqxmd.com/read/28912128/aging-modifies-the-effect-of-cardiac-output-on-middle-cerebral-artery-blood-flow-velocity
#4
Anne-Sophie G T Bronzwaer, Jasper Verbree, Wim J Stok, Mat J A P Daemen, Mark A van Buchem, Matthias J P van Osch, Johannes J van Lieshout
An association between cerebral blood flow (CBF) and cardiac output (CO) has been established in young healthy subjects. As of yet it is unclear how this association evolves over the life span. To that purpose, we continuously recorded mean arterial pressure (MAP; finger plethysmography), CO (pulse contour; CO-trek), mean blood flow velocity in the middle cerebral artery (MCAV; transcranial Doppler ultrasonography), and end-tidal CO2 partial pressure (PetCO2) in healthy young (19-27 years), middle-aged (51-61 years), and elderly subjects (70-79 years)...
September 2017: Physiological Reports
https://www.readbyqxmd.com/read/28906205/preventing-cognitive-decline-and-dementia-from-cerebral-small-vessel-disease-the-laci-1-trial-protocol-and-statistical-analysis-plan-of-a-phase-iia-dose-escalation-trial-testing-tolerability-safety-and-effect-on-intermediary-endpoints-of-isosorbide-mononitrate
#5
Gordon W Blair, Jason P Appleton, Zhe Kang Law, Fergus Doubal, Katie Flaherty, Richard Dooley, Kirsten Shuler, Carla Richardson, Iona Hamilton, Yulu Shi, Michael Stringer, Julia Boyd, Michael J Thrippleton, Nikola Sprigg, Philip M Bath, Joanna M Wardlaw
Rationale The pathophysiology of most lacunar stroke, a form of small vessel disease, is thought to differ from large artery atherothrombo- or cardio-embolic stroke. Licensed drugs, isosorbide mononitrate and cilostazol, have promising mechanisms of action to support their testing to prevent stroke recurrence, cognitive impairment, or radiological progression after lacunar stroke. Aim LACI-1 will assess the tolerability, safety, and efficacy, by dose, of isosorbide mononitrate and cilostazol, alone and in combination, in patients with ischemic lacunar stroke...
January 1, 2017: International Journal of Stroke: Official Journal of the International Stroke Society
https://www.readbyqxmd.com/read/28904458/can-transcranial-color-doppler-spectral-signatures-be-a-novel-biomarker-for-monitoring-cerebrovascular-autoregulation-and-intracranial-pressure-a-speculative-synthesis
#6
Sandhya Mangalore, Kotresh, Rakshith Srinivasa, Alangar Sathyaranjandas Hegde, Rangashetty Srinivasa
BACKGROUND: Trans Cranial Colour Doppler (TCCD) has been extensively used in various neurological and neurosurgical conditions causing severe raise in the intracranial pressure (ICP). MATERIAL AND METHOD: Our study explores the sequential evolution of TCCD flow pattern by correlating with pupillary reactivity, Glasgow coma scale (GCS), and imaging. Our cohort consisted of thirty patients with ten patients in each subgroup admitted to the neuro-Intensive Care Unit (NICU) for various neurological and neurosurgical causes...
July 2017: Annals of Indian Academy of Neurology
https://www.readbyqxmd.com/read/28904456/association-of-serum-25-hydroxyvitamin-d-in-carotid-intima-media-thickness-a-study-from-south-india
#7
Jaydip Ray Chauduri, K Rukmini Mridula, Matapathi Umamashesh, Banda Balaraju, V C S Srinivasarao Bandaru
BACKGROUND: Abnormal carotid intima-media thickness (IMT) is a marker of carotid atherosclerosis which is a risk factor for cerebrovascular and cardiovascular diseases. Recent studies have found an association of 25-hydroxyvitamin D deficiency with abnormal carotid IMT. PURPOSE: The purpose of the study was to investigate the association of serum 25-hydroxyvitamin D levels with carotid IMT in Indian participants. MATERIALS AND METHODS: We prospectively recruited 300 participants at Yashoda Hospital, Hyderabad, during the study period between January 2012 and December 2014...
July 2017: Annals of Indian Academy of Neurology
https://www.readbyqxmd.com/read/28871418/time-spent-with-impaired-autoregulation-is-linked-with-outcome-in-severe-infant-paediatric-traumatic-brain-injury
#8
Konstantin Hockel, Jennifer Diedler, Felix Neunhoeffer, Ellen Heimberg, Carmen Nagel, Martin U Schuhmann
BACKGROUND: It could be shown in traumatic brain injury (TBI) in adults that the functional status of cerebrovascular autoregulation (AR), determined by the pressure reactivity index (PRx), correlates to and even predicts outcome. We investigated PRx, cerebral perfusion pressure (CPP) and intracranial pressure (ICP) and their correlation to outcome in severe infant and paediatric TBI. METHODS: Seventeen patients (range, 1 day to 14 years) with severe TBI (median GCS at presentation, 4) underwent long-term computerised ICP and mean arterial pressure (MAP) monitoring using dedicated software to determine CPP and PRx and optimal CPP (CPP level where PRx shows best autoregulation) continuously...
September 4, 2017: Acta Neurochirurgica
https://www.readbyqxmd.com/read/28869425/effects-of-low-oxygen-dead-space-ventilation-and-breath-holding-test-in-evaluating-cerebrovascular-reactivity-a-comparative-observation
#9
Ke-Ju Ju, Ling-Ling Zhong, Xiao-Yu Ni, Lei Xia, Liu-Jun Xue, Guan-Liang Cheng
OBJECTIVE: This study aims to explore the application prospect of low oxygen dead space ventilation (LODSV) in evaluating vasomotor reactivity (VMR) by comparison between LODSV and breath-holding test (BHT). METHODS: Outpatient or inpatient patients who underwent transcranial Doppler sonography (TCD) were enrolled into this study. These patients successively underwent BHT and LODSV. The cooperation degree, tolerance conditions and adverse reactions in patients were recorded, and VMR was calculated, compared and analyzed...
2017: Bio-medical Materials and Engineering
https://www.readbyqxmd.com/read/28860455/age-differences-in-brain-signal-variability-are-robust-to-multiple-vascular-controls
#10
Douglas D Garrett, Ulman Lindenberger, Richard D Hoge, Claudine J Gauthier
A host of studies support that younger, better performing adults express greater moment-to-moment blood oxygen level-dependent (BOLD) signal variability (SDBOLD) in various cortical regions, supporting an emerging view that the aging brain may undergo a generalized reduction in dynamic range. However, the exact physiological nature of age differences in SDBOLD remains understudied. In a sample of 29 younger and 45 older adults, we examined the contribution of vascular factors to age group differences in fixation-based SDBOLD using (1) a dual-echo BOLD/pseudo-continuous arterial spin labeling (pCASL) sequence, and (2) hypercapnia via a computer-controlled gas delivery system...
August 31, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28835309/impaired-cerebral-autoregulation-and-elevation-in-plasma-glial-fibrillary-acidic-protein-level-during-cardiopulmonary-bypass-surgery-for-chd
#11
Ronald B Easley, Bradley S Marino, Jacky Jennings, Amy E Cassedy, Kathleen K Kibler, Ken M Brady, Dean B Andropoulos, Marissa Brunetti, Charles W Hogue, Eugenie S Heitmiller, Jennifer K Lee, James Spaeth, Allen D Everett
BACKGROUND: Cerebrovascular reactivity monitoring has been used to identify the lower limit of pressure autoregulation in adult patients with brain injury. We hypothesise that impaired cerebrovascular reactivity and time spent below the lower limit of autoregulation during cardiopulmonary bypass will result in hypoperfusion injuries to the brain detectable by elevation in serum glial fibrillary acidic protein level. METHODS: We designed a multicentre observational pilot study combining concurrent cerebrovascular reactivity and biomarker monitoring during cardiopulmonary bypass...
August 24, 2017: Cardiology in the Young
https://www.readbyqxmd.com/read/28819737/further-controversies-about-brain-tissue-oxygenation-pressure-reactivity-after-traumatic-brain-injury
#12
Morten Andresen, Joseph Donnelly, Marcel Aries, Marianne Juhler, David Menon, Pja Hutchinson, Peter Smielewski
BACKGROUND: Continuous monitoring of cerebral autoregulation is considered clinically useful due to its ability to warn against brain ischemic insults, which may translate to a relationship with adverse outcome. It is typically performed using the pressure reactivity index (PRx) based on mean arterial pressure and intracranial pressure. A new ORx index based on brain tissue oxygenation and cerebral perfusion pressure (CPP) has been proposed that similarly allows for evaluation of cerebrovascular reactivity...
August 17, 2017: Neurocritical Care
https://www.readbyqxmd.com/read/28816837/individualizing-thresholds-of-cerebral-perfusion-pressure-using-estimated-limits-of-autoregulation
#13
Joseph Donnelly, Marek Czosnyka, Hadie Adams, Chiara Robba, Luzius A Steiner, Danilo Cardim, Brenno Cabella, Xiuyun Liu, Ari Ercole, Peter John Hutchinson, David Krishna Menon, Marcel J H Aries, Peter Smielewski
OBJECTIVES: In severe traumatic brain injury, cerebral perfusion pressure management based on cerebrovascular pressure reactivity index has the potential to provide a personalized treatment target to improve patient outcomes. So far, the methods have focused on identifying "one" autoregulation-guided cerebral perfusion pressure target-called "cerebral perfusion pressure optimal". We investigated whether a cerebral perfusion pressure autoregulation range-which uses a continuous estimation of the "lower" and "upper" cerebral perfusion pressure limits of cerebrovascular pressure autoregulation (assessed with pressure reactivity index)-has prognostic value...
September 2017: Critical Care Medicine
https://www.readbyqxmd.com/read/28804779/language-mapping-using-t2-prepared-bold-functional-mri-in-the-presence-of-large-susceptibility-artifacts-initial-results-in-patients-with-brain-tumor-and-epilepsy
#14
Jun Hua, Xinyuan Miao, Shruti Agarwal, Chetan Bettegowda, Alfredo Quiñones-Hinojosa, John Laterra, Peter C M Van Zijl, James J Pekar, Jay J Pillai
At present, presurgical functional mapping is the most prevalent clinical application of functional magnetic resonance imaging (fMRI). Signal dropouts and distortions caused by susceptibility effects in the current standard echo planar imaging (EPI)-based fMRI images are well-known problems and pose a major hurdle for the application of fMRI in several brain regions, many of which are related to language mapping in presurgical planning. Such artifacts are particularly problematic in patients with previous surgical resection cavities, craniotomy hardware, hemorrhage, and vascular malformation...
June 2017: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/28778000/non-proinflammatory-and-responsive-nanoplatforms-for-targeted-treatment-of-atherosclerosis
#15
Yin Dou, Yue Chen, Xiangjun Zhang, Xiaoqiu Xu, Yidan Chen, Jiawei Guo, Dinglin Zhang, Ruibing Wang, Xiaohui Li, Jianxiang Zhang
Atherosclerosis is the leading cause of many fatal cardiovascular and cerebrovascular diseases. Whereas nanomedicines are promising for targeted therapy of atherosclerosis, great challenges remain in development of effective, safe, and translational nanotherapies for its treatment. Herein we hypothesize that non-proinflammatory nanomaterials sensitive to low pH or high reactive oxygen species (ROS) may serve as effective platforms for triggerable delivery of anti-atherosclerotic therapeutics in cellular and tissue microenvironments of inflammation...
July 29, 2017: Biomaterials
https://www.readbyqxmd.com/read/28776469/relationship-between-haemodynamic-impairment-and-collateral-blood-flow-in-carotid-artery-disease
#16
Nolan S Hartkamp, Esben T Petersen, Michael A Chappell, Thomas W Okell, Maarten Uyttenboogaart, Clark J Zeebregts, Reinoud Ph Bokkers
Collateral blood flow plays a pivotal role in steno-occlusive internal carotid artery (ICA) disease to prevent irreversible ischaemic damage. Our aim was to investigate the effect of carotid artery disease upon cerebral perfusion and cerebrovascular reactivity and whether haemodynamic impairment is influenced at brain tissue level by the existence of primary and/or secondary collateral. Eighty-eight patients with steno-occlusive ICA disease and 29 healthy controls underwent MR examination. The presence of collaterals was determined with time-of-flight, two-dimensional phase contrast MRA and territorial arterial spin labeling (ASL) imaging...
January 1, 2017: Journal of Cerebral Blood Flow and Metabolism
https://www.readbyqxmd.com/read/28769857/hyperventilation-therapy-for-control-of-posttraumatic-intracranial-hypertension
#17
REVIEW
Daniel Agustín Godoy, Ali Seifi, David Garza, Santiago Lubillo-Montenegro, Francisco Murillo-Cabezas
During traumatic brain injury, intracranial hypertension (ICH) can become a life-threatening condition if it is not managed quickly and adequately. Physicians use therapeutic hyperventilation to reduce elevated intracranial pressure (ICP) by manipulating autoregulatory functions connected to cerebrovascular CO2 reactivity. Inducing hypocapnia via hyperventilation reduces the partial pressure of arterial carbon dioxide (PaCO2), which incites vasoconstriction in the cerebral resistance arterioles. This constriction decrease cerebral blood flow, which reduces cerebral blood volume and, ultimately, decreases the patient's ICP...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28756241/rapid-cerebrovascular-reactivity-mapping-enabling-vascular-reactivity-information-to-be-routinely-acquired
#18
Nicholas P Blockley, James W Harkin, Daniel P Bulte
Cerebrovascular reactivity mapping (CVR), using magnetic resonance imaging (MRI) and carbon dioxide as a stimulus, provides useful information on how cerebral blood vessels react under stress. This information has proven to be useful in the study of vascular disorders, dementia and healthy ageing. However, clinical adoption of this form of CVR mapping has been hindered by relatively long scan durations of 7-12 min. By replacing the conventional block presentation of carbon dioxide enriched air with a sinusoidally modulated stimulus, the aim of this study was to investigate whether more clinically acceptable scan durations are possible...
July 26, 2017: NeuroImage
https://www.readbyqxmd.com/read/28753475/presenilin-1-mutation-decreases-both-calcium-and-contractile-responses-in-cerebral-arteries
#19
Xavier Toussay, Jean-Luc Morel, Nathalie Biendon, Lolita Rotureau, François-Pierre Legeron, Marie-Charlotte Boutonnet, Yoon H Cho, Nathalie Macrez
Mutations or upregulation in presenilin 1 (PS1) gene are found in familial early-onset Alzheimer's disease or sporadic late-onset Alzheimer's disease, respectively. PS1 has been essentially studied in neurons and its mutation was shown to alter intracellular calcium (Ca(2+)) signals. Here, we showed that PS1 is expressed in smooth muscle cells (SMCs) of mouse cerebral arteries, and we assessed the effects of the deletion of exon 9 of PS1 (PS1dE9) on Ca(2+) signals and contractile responses of vascular SMC. Agonist-induced contraction of cerebral vessels was significantly decreased in PS1dE9 both in vivo and ex vivo...
June 24, 2017: Neurobiology of Aging
https://www.readbyqxmd.com/read/28742817/temporal-profile-of-intracranial-pressure-and-cerebrovascular-reactivity-in-severe-traumatic-brain-injury-and-association-with-fatal-outcome-an-observational-study
#20
Hadie Adams, Joseph Donnelly, Marek Czosnyka, Angelos G Kolias, Adel Helmy, David K Menon, Peter Smielewski, Peter J Hutchinson
BACKGROUND: Both intracranial pressure (ICP) and the cerebrovascular pressure reactivity represent the dysregulation of pathways directly involved in traumatic brain injury (TBI) pathogenesis and have been used to inform clinical management. However, how these parameters evolve over time following injury and whether this evolution has any prognostic importance have not been studied. METHODS AND FINDINGS: We analysed the temporal profile of ICP and pressure reactivity index (PRx), examined their relation to TBI-specific mortality, and determined if the prognostic relevance of these parameters was affected by their temporal profile using mixed models for repeated measures of ICP and PRx for the first 240 hours from the time of injury...
July 2017: PLoS Medicine
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