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Kells AM, Moir ME, Coombs GB, D'Souza AW, Klassen SA, Al-Khazraji BK, Shoemaker JK. No influence of steady-state postural changes on cerebrovascular compliance in humans. Appl Physiol Nutr Metab 2024; 49:1210-1216. [PMID: 38776557 DOI: 10.1139/apnm-2023-0447] [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] [Indexed: 05/25/2024]
Abstract
The aim of this study was to determine the effect of posture changes on vascular compliance in intracranial (brain) versus extracranial vascular beds (forearm). Eighteen young adults (nine females) performed a supine-to-seated-to-standing protocol involving 5 min of rest in each position. Continuous blood pressure, middle cerebral artery (MCA) blood velocity, and brachial artery blood velocity were recorded at each posture. Three to five consecutive steady-state cardiac cycles at each posture were analyzed by a four-element lumped parameter modified Windkessel model to calculate vascular compliance. Mean arterial pressure (MAP) increased from supine to seated (76(9) vs. 81(12) mmHg; P = 0.006) and from supine to standing (76(9) vs. 82(13) mmHg; P = 0.034). Mean blood flow was greater in the MCA relative to the forearm (forearm: 40(5) mL·min-1, MCA: 224(17) mL·min-1; main effect P < 0.001). Conversely, vascular resistance (forearm: 3.25(0.50) mmHg-1·mL·min-1, brain: 0.36(0.04) mmHg-1·mL·min-1; main effect P < 0.001) and compliance (forearm: 0.010(0.001) mL·min-1·mmHg-1, brain: 0.005(0.001) mL·min-1·mmHg-1; main effect P = 0.001) were greater in the forearm compared to the brain. Significant main effects of posture were observed with decreasing values in upright positions for mean blood flow (P = 0.001) in both vascular beds, but not for resistance (P = 0.163) or compliance (P = 0.385). There were no significant interaction effects between vascular bed and posture for mean flow (P = 0.057), resistance (P = 0.258), or compliance (P = 0.329). This study provides evidence that under steady-state conditions, posture does not affect cerebrovascular compliance.
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Affiliation(s)
- Alicia M Kells
- School of Kinesiology, Western University, London, ON, Canada
| | - M Erin Moir
- School of Kinesiology, Western University, London, ON, Canada
| | - Geoff B Coombs
- School of Kinesiology, Western University, London, ON, Canada
- Department of Kinesiology, McMaster University, Hamilton, ON, Canada
| | | | - Stephen A Klassen
- School of Kinesiology, Western University, London, ON, Canada
- Department of Kinesiology, Brock University, St. Catharines, ON, Canada
| | - Baraa K Al-Khazraji
- School of Kinesiology, Western University, London, ON, Canada
- Department of Kinesiology, McMaster University, Hamilton, ON, Canada
| | - J Kevin Shoemaker
- School of Kinesiology, Western University, London, ON, Canada
- Department of Physiology and Pharmacology, Western University, London, ON, Canada
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Sparks S, Hayes G, Pinto J, Bulte D. Characterising cerebrovascular reactivity and the pupillary light response-a comparative study. Front Physiol 2024; 15:1384113. [PMID: 39175613 PMCID: PMC11338921 DOI: 10.3389/fphys.2024.1384113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Accepted: 07/29/2024] [Indexed: 08/24/2024] Open
Abstract
Introduction Smooth muscle is integral to multiple autonomic systems, including cerebrovascular dynamics through vascular smooth muscle cells and in ocular muscle dynamics, by regulating pupil size. In the brain, smooth muscle function plays a role in cerebrovascular reactivity (CVR) that describes changes in blood vessel calibre in response to vasoactive stimuli. Similarly, pupil size regulation can be measured using the pupillary light response (PLR), the pupil's reaction to changes in light levels. The primary aim of this study was to explore the interplay between cerebral blood flow and pupil dynamics, evaluated using CVR and PLR, respectively. Methods A total of 20 healthy adults took part in a CVR gas stimulus protocol and a light and dark flash PLR protocol. CVR was calculated as the blood flow velocity change in the middle cerebral artery, measured using transcranial Doppler ultrasound in response to a 5% increase in CO2. Multiple PLR metrics were evaluated with a clinical pupillometer. Results CVR and PLR metrics were all within the expected physiological ranges for healthy adults. Nine different PLR metrics, assessed through the light and dark flash protocols, were compared against CVR. A significant negative relationship was observed between the latency of the PLR in the dark flash protocol and CVR. No statistically significant relationships were found between CVR and other PLR metrics. Conclusion This is the first study to investigate the relationship between cerebral blood flow and pupil dynamics. A significant relationship between dark flash latency and CVR was observed. Future work includes evaluating these relationships using more robust CVR and PLR measurement techniques in a larger, more diverse cohort. Notably, more research is warranted into the PLR using a dark flash protocol and its connection to cerebrovascular function.
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Affiliation(s)
| | | | | | - Daniel Bulte
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, United Kingdom
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Davies A, Gurung D, Ladthavorlaphatt K, Mankoo A, Panerai RB, Robinson TG, Minhas JS, Beishon LC. The effect of CO 2 on the age dependence of neurovascular coupling. J Appl Physiol (1985) 2024; 137:445-459. [PMID: 38961823 DOI: 10.1152/japplphysiol.00695.2023] [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: 09/29/2023] [Revised: 06/27/2024] [Accepted: 06/27/2024] [Indexed: 07/05/2024] Open
Abstract
Prior studies have identified variable effects of aging on neurovascular coupling (NVC). Carbon dioxide (CO2) affects both cerebral blood velocity (CBv) and NVC, but the effects of age on NVC under different CO2 conditions are unknown. Therefore, we investigated the effects of aging on NVC in different CO2 states during cognitive paradigms. Seventy-eight participants (18-78 yr), with well-controlled comorbidities, underwent continuous recordings of CBv by bilateral insonation of middle (MCA) and posterior (PCA) cerebral arteries (transcranial Doppler), blood pressure, end-tidal CO2, and heart rate during poikilocapnia, hypercapnia (5% CO2 inhalation), and hypocapnia (paced hyperventilation). Neuroactivation via visuospatial (VS) and attention tasks (AT) was used to stimulate NVC. Peak percentage and absolute change in MCAv/PCAv, were compared between CO2 conditions and age groups (≤30, 31-60, and >60 yr). For the VS task, in poikilocapnia, younger adults had a lower NVC response compared with older adults [mean difference (MD): -7.92% (standard deviation (SD): 2.37), P = 0.004], but comparable between younger and middle-aged groups. In hypercapnia, both younger [MD: -4.75% (SD: 1.56), P = 0.009] and middle [MD: -4.58% (SD: 1.69), P = 0.023] age groups had lower NVC responses compared with older adults. Finally, in hypocapnia, both older [MD: 5.92% (SD: 2.21), P = 0.025] and middle [MD: 5.44% (SD: 2.27), P = 0.049] age groups had greater NVC responses, compared with younger adults. In conclusion, the magnitude of NVC response suppression from baseline during hyper- and hypocapnia, did not differ significantly between age groups. However, the middle age group demonstrated a different NVC response while under hypercapnic conditions, compared with hypocapnia.NEW & NOTEWORTHY This study describes the effects of age on neurovascular coupling under altered CO2 conditions. We demonstrated that both hypercapnia and hypocapnia suppress neurovascular coupling (NVC) responses. Furthermore, that middle age exhibits an NVC response comparable with younger adults under hypercapnia, and older adults under hypocapnia.
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Affiliation(s)
- Aaron Davies
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
| | - Dewarkar Gurung
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
| | - Kannaphob Ladthavorlaphatt
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
| | - Alex Mankoo
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
| | - Ronney B Panerai
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- NIHR Leicester Biomedical Research Centre, Glenfield Research Centre, British Heart Foundation Cardiovascular Centre, Leicester, United Kingdom
| | - Thompson G Robinson
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- NIHR Leicester Biomedical Research Centre, Glenfield Research Centre, British Heart Foundation Cardiovascular Centre, Leicester, United Kingdom
| | - Jatinder S Minhas
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- NIHR Leicester Biomedical Research Centre, Glenfield Research Centre, British Heart Foundation Cardiovascular Centre, Leicester, United Kingdom
| | - Lucy C Beishon
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- NIHR Leicester Biomedical Research Centre, Glenfield Research Centre, British Heart Foundation Cardiovascular Centre, Leicester, United Kingdom
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Carvalho LB, Kaffenberger T, Chambers B, Borschmann K, Levi C, Churilov L, Thijs V, Bernhardt J. Cerebral hemodynamic response to upright position in acute ischemic stroke. Front Neurol 2024; 15:1392773. [PMID: 39055319 PMCID: PMC11269199 DOI: 10.3389/fneur.2024.1392773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 06/24/2024] [Indexed: 07/27/2024] Open
Abstract
Introduction Concerns exist that a potential mechanism for harm from upright activity (sitting, standing, and walking) early after an acute ischaemic stroke could be the reduction of cerebral perfusion during this critical phase. We aimed to estimate the effects of upright positions (sitting and standing) on cerebral hemodynamics within 48 h and later, 3-7 days post-stroke, in patients with strokes with and without occlusive disease and in controls. Methods We investigated MCAv using transcranial Doppler in 0° head position, then at 30°, 70°, 90° sitting, and 90° standing, at <48 h post-stroke, and later at 3-7 days post-stroke. Mixed-effect linear regression modeling was used to estimate differences in MCAv between the 0° and other positions and to compare MCAv changes across groups. Results A total of 42 stroke participants (anterior and posterior circulation) (13 with occlusive disease, 29 without) and 22 controls were recruited. Affected hemisphere MCAv decreased in strokes with occlusive disease (<48 h post-stroke): from 0° to 90° sitting (-9.9 cm/s, 95% CI[-16.4, -3.4]) and from 0° to 90° standing (-7.1 cm/s, 95%CI[-14.3, -0.01]). Affected hemisphere MCAv also decreased in strokes without occlusive disease: from 0° to 90° sitting (-3.3 cm/s, 95%CI[-5.6, -1.1]) and from 0° to 90° standing (-3.6 cm/s, 95%CI [-5.9, -1.3]) (p-value interaction stroke with vs. without occlusive disease = 0.07). A decrease in MCAv when upright was also observed in controls: from 0° to 90° sitting (-3.8 cm/s, 95%CI[-6.0, -1.63]) and from 0° to 90° standing (-3 cm/s, 95%CI[-5.2, -0.81]) (p-value interaction stroke vs. controls = 0.85). Subgroup analysis of anterior circulation stroke showed similar patterns of change in MCAv in the affected hemisphere, with a significant interaction between those with occlusive disease (n = 11) and those without (n = 26) (p = 0.02). Changes in MCAv from 0° to upright at <48 h post-stroke were similar to 3-7 days. No association between changes in MCAv at <48 h and the 30-day modified Rankin Scale was found. Discussion Moving to more upright positions <2 days post-stroke does reduce MCAv in the affected hemisphere; however, these changes were not significantly different for stroke participants (anterior and posterior circulation) with and without occlusive disease, nor for controls. The decrease in MCAv in anterior circulation stroke with occlusive disease significantly differed from without occlusive disease. However, the sample size was small, and more research is warranted to confirm these findings.
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Affiliation(s)
- Lilian B. Carvalho
- Stroke Theme, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Heidelberg, VIC, Australia
| | - Tina Kaffenberger
- Stroke Theme, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Heidelberg, VIC, Australia
| | - Brian Chambers
- Neurology Department, Austin Health, Melbourne, VIC, Australia
| | - Karen Borschmann
- Stroke Theme, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Heidelberg, VIC, Australia
- Allied Health, St Vincent's Hospital, Melbourne, VIC, Australia
| | - Christopher Levi
- John Hunter Hospital, University of Newcastle, Newcastle, NSW, Australia
| | - Leonid Churilov
- Department of Medicine (Austin Health) and Melbourne Brain Centre at Royal Melbourne Hospital, Melbourne Medical School, University of Melbourne, Melbourne, VIC, Australia
| | - Vincent Thijs
- Stroke Theme, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Heidelberg, VIC, Australia
- Neurology Department, Austin Health, Melbourne, VIC, Australia
| | - Julie Bernhardt
- Stroke Theme, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Heidelberg, VIC, Australia
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Coelho FMS, de Carvalho Cremaschi RM, Novak P. Cerebral blood flow and end-tidal CO 2 predict lightheadedness during head-up tilt in patients with orthostatic intolerance. Neurol Sci 2024:10.1007/s10072-024-07673-8. [PMID: 38980457 DOI: 10.1007/s10072-024-07673-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Accepted: 06/20/2024] [Indexed: 07/10/2024]
Abstract
Orthostatic intolerance (OI) is a common problem. Reliable markers of OI are missing, as orthostatic blood pressure and heart rate poorly correlate with orthostatic symptoms. The objective of this study was to assess the relationship between orthostatic lightheadedness and cerebral blood flow. In this retrospective study patients with OI were evaluated at the Autonomic Laboratory of the Department of Neurology, Brigham and Women's Faulkner Hospital, Boston. The 10-minute head-up tilt test was performed as a part of autonomic testing. Orthostatic lightheadedness was evaluated at every minute of the head-up tilt. Heart rate, blood pressure, capnography, and cerebral blood flow velocity (CBFv) in the middle cerebral artery using transcranial Doppler were measured. Repeated-measures design with a linear mixed-effects model was used to evaluate the relationship between orthostatic lightheadedness and hemodynamic variables. Correlation analyses were done by calculating Pearson's coefficient. Twenty-two patients with OI were compared to nineteen controls. Orthostatic CBFv and end-tidal CO2 decreased in OI patients compared to controls (p < 0.001) and predicted orthostatic lightheadedness. Orthostatic heart rate and blood pressure failed to predict orthostatic lightheadedness. The lightheadedness threshold, which marked the onset of lightheadedness, was equal to an average systolic CBFv decrease of 18.92% and end-tidal CO2 of 12.82%. The intensity of lightheadedness was proportional to the CBFv and end-tidal CO2 decline. Orthostatic lightheadedness correlated with systolic CBFv (r=-0.6, p < 0.001) and end-tidal CO2 (r=-0.33, p < 0.001) decline. In conclusion, orthostatic CBFv and end-tidal CO2 changes predict orthostatic lightheadedness and can be used as objective markers of OI.
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Affiliation(s)
- Fernando Morgadinho Santos Coelho
- Department of Neurology, Brigham and Women's Faulkner Hospital, 1153 Centre Street, Boston, MA, USA
- Departamento de Neurologia e Neurocirurgia, Universidade Federal de São Paulo, São Paulo, SP, Brazil
| | - Renata Maria de Carvalho Cremaschi
- Department of Neurology, Brigham and Women's Faulkner Hospital, 1153 Centre Street, Boston, MA, USA
- Departamento de Neurologia e Neurocirurgia, Universidade Federal de São Paulo, São Paulo, SP, Brazil
| | - Peter Novak
- Department of Neurology, Brigham and Women's Faulkner Hospital, 1153 Centre Street, Boston, MA, USA.
- Harvard Medical School, Boston, MA, USA.
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Ladthavorlaphatt K, Surti FBS, Beishon LC, Robinson TG, Panerai RB. Depression of dynamic cerebral autoregulation during neural activation: The role of responders and non-responders. J Cereb Blood Flow Metab 2024; 44:1231-1245. [PMID: 38301726 PMCID: PMC11179612 DOI: 10.1177/0271678x241229908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 12/15/2023] [Accepted: 12/28/2023] [Indexed: 02/03/2024]
Abstract
Neurovascular coupling (NVC) interaction with dynamic cerebral autoregulation (dCA) remains unclear. We investigated the effect of task complexity and duration on the interaction with dCA. Sixteen healthy participants (31.6 ± 11.6 years) performed verbal fluency (naming-words (NW)) and serial subtraction (SS) paradigms, of varying complexity, at durations of 05, 30 and 60 s. The autoregulation index (ARI), was estimated from the bilateral middle cerebral artery blood velocity (MCAv) step response, calculated by transfer function analysis (TFA), for each paradigm during unstimulated (2 min) and neuroactivated (1 min) segments. Intraclass correlation (ICC) and coefficient of variation (CV) determined reproducibility for two visits and objective criteria were applied to classify responders (R) and non-responders (NoR) to task-induced MCAv increase. ICC values demonstrated fair reproducibility in all tasks. ARI decreased in right (RH) and left (LH) hemispheres, irrespective of paradigm complexity and duration (p < 0.0001). Bilateral ARI estimates were significantly decreased during NW for the R group only (p < 0.0001) but were reduced in both R (p < 0.0001) and NoR (p = 0.03) groups for SS tasks compared with baseline. The reproducible attenuation of dCA efficiency due to paradigm-induced NVC response, its interaction, and different behaviour in R and NoR, warrant further research in different physiological and clinical conditions.
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Affiliation(s)
- Kannaphob Ladthavorlaphatt
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
- Medical Diagnostics Unit, Thammasat University Hospital, Thammasat University, Pathum Thani, Thailand
- Thammasat University Centre of Excellence in Computational Mechanics and Medical Engineering, Thammasat University, Pathum Thani, Thailand
| | - Farhaana BS Surti
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
| | - Lucy C Beishon
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
- NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, UK
| | - Thompson G Robinson
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
- NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, UK
| | - Ronney B Panerai
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
- NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, UK
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Medow MS, Stewart JM. Phenylephrine alters phase synchronization between cerebral blood velocity and blood pressure in ME/CFS with orthostatic intolerance. Am J Physiol Regul Integr Comp Physiol 2024; 326:R599-R608. [PMID: 38682242 PMCID: PMC11381003 DOI: 10.1152/ajpregu.00071.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 04/16/2024] [Accepted: 04/19/2024] [Indexed: 05/01/2024]
Abstract
Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) with orthostatic intolerance (OI) is characterized by neurocognitive deficits perhaps related to upright hypocapnia and loss of cerebral autoregulation (CA). We performed N-back neurocognition testing and calculated the phase synchronization index (PhSI) between arterial pressure (AP) and cerebral blood velocity (CBV) as a time-dependent measurement of cerebral autoregulation in 11 control (mean age = 24.1 yr) and 15 patients with ME/CFS (mean age = 21.8 yr). All patients with ME/CFS had postural tachycardia syndrome (POTS). A 10-min 60° head-up tilt (HUT) significantly increased heart rate (109.4 ± 3.9 vs. 77.2 ± 1.6 beats/min, P < 0.05) and respiratory rate (20.9 ± 1.7 vs. 14.2 ± 1.2 breaths/min, P < 0.05) and decreased end-tidal CO2 (ETCO2; 33.9 ± 1.1 vs. 42.8 ± 1.2 Torr, P < 0.05) in ME/CFS versus control. In ME/CFS, HUT significantly decreased CBV compared with control (-22.5% vs. -8.7%, P < 0.005). To mitigate the orthostatic CBV reduction, we administered supplemental CO2, phenylephrine, and acetazolamide and performed N-back testing supine and during HUT. Only phenylephrine corrected the orthostatic decrease in neurocognition by reverting % correct n = 4 N-back during HUT in ME/CFS similar to control (ME/CFS = 38.5 ± 5.5 vs. ME/CFS + PE= 65.6 ± 5.7 vs. Control 56.9 ± 7.5). HUT in ME/CFS resulted in increased PhSI values indicating decreased CA. Although CO2 and acetazolamide had no effect on PhSI in ME/CFS, phenylephrine caused a significant reduction in PhSI (ME/CFS = 0.80 ± 0.03 vs. ME/CFS + PE= 0.69 ± 0.04, P < 0.05) and improved cerebral autoregulation. Thus, PE improved neurocognitive function in patients with ME/CFS, perhaps related to improved neurovascular coupling, cerebral autoregulation, and maintenance of CBV.NEW & NOTEWORTHY We evaluated cognitive function before and after CO2, acetazolamide, and phenylephrine, which mitigate orthostatic reductions in cerebral blood velocity. Neither CO2 nor acetazolamide affected N-back testing (% correct answers) during an orthostatic challenge. Only phenylephrine improved upright N-back performance in ME/CFS, as it both blocked hyperventilation and increased CO2 significantly compared with those untreated. And only phenylephrine resulted in improved PSI values in both ME/CFS and control while upright, suggesting improved cerebral autoregulation.
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Affiliation(s)
- Marvin S Medow
- Department of Pediatrics, New York Medical College, Valhalla, New York, United States
- Department of Physiology, New York Medical College, Valhalla, New York, United States
| | - Julian M Stewart
- Department of Pediatrics, New York Medical College, Valhalla, New York, United States
- Department of Physiology, New York Medical College, Valhalla, New York, United States
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Monteiro A, Castro P, Pereira G, Ferreira C, Polonia J, Lobo M, Azevedo E. Cerebral blood flow regulation and cognitive performance in hypertension. J Cereb Blood Flow Metab 2024:271678X241254680. [PMID: 38738526 DOI: 10.1177/0271678x241254680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/14/2024]
Abstract
We examined the relation between transcranial Doppler (TCD) markers of cerebral blood flow regulation and cognitive performance in hypertension (HT) patients to evaluate the predictive value of these markers for cognitive decline. We assessed dynamic cerebral autoregulation (dCA), vasoreactivity to carbon dioxide, and neurovascular coupling (NVC) in the middle (MCA) and posterior (PCA) cerebral arteries of 52 patients. Neuropsychological evaluation included the Montreal Cognitive Assessment and tests covering attention, executive function, processing speed, and memory. Notably, reduced rate time in the PCA significantly predicted better processing speed (p = 0.003). Furthermore, reduced overshoot systolic cerebral blood velocity in the PCA and reduced phase in the VLF range in the MCA (p = 0.021 and p = 0.017, respectively) significantly predicted better memory. Intriguingly, enhanced dCA in the MCA predicted poorer memory performance, while reduced NVC in the PCA predicted both superior processing speed and memory performance. These findings suggest that HT-induced changes in cerebral hemodynamics impact cognitive performance. Further research should verify these observations and elucidate whether these changes represent adaptive responses or neurovascular inefficiency. TCD markers might provide insights into HT-related cognitive decline.
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Affiliation(s)
- Ana Monteiro
- UnIC@RISE, Department of Clinical Neurosciences and Mental Health, Faculty of Medicine of University of Porto, Porto, Portugal
- Department of Neurology, Unidade Local de Saúde Alto Ave - Hospital de Guimarães, E.P.E., Guimarães, Portugal
| | - Pedro Castro
- UnIC@RISE, Department of Clinical Neurosciences and Mental Health, Faculty of Medicine of University of Porto, Porto, Portugal
- Department of Neurology, Centro Hospitalar Universitário de São João, E.P.E., Porto, Portugal
| | - Gilberto Pereira
- Department of Neurology, Centro Hospitalar Universitário de São João, E.P.E., Porto, Portugal
| | - Carmen Ferreira
- Department of Neurology, Centro Hospitalar Universitário de São João, E.P.E., Porto, Portugal
| | - Jorge Polonia
- CINTESIS@RISE, Department of Medicine, Faculty of Medicine of University of Porto, Porto, Portugal
- Hypertension and Cardiovascular Risk Unit, Unidade Local de Saúde de Matosinhos, Matosinhos, Portugal
| | - Mariana Lobo
- CINTESIS@RISE, MEDCIDS Department, Faculty of Medicine of University of Porto, Porto, Portugal
| | - Elsa Azevedo
- UnIC@RISE, Department of Clinical Neurosciences and Mental Health, Faculty of Medicine of University of Porto, Porto, Portugal
- Department of Neurology, Centro Hospitalar Universitário de São João, E.P.E., Porto, Portugal
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Crippa IA, Vincent JL, Zama Cavicchi F, Pozzebon S, Gaspard N, Maenhout C, Creteur J, Taccone FS. Estimated Cerebral Perfusion Pressure and Intracranial Pressure in Septic Patients. Neurocrit Care 2024; 40:577-586. [PMID: 37420137 DOI: 10.1007/s12028-023-01783-5] [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: 02/02/2023] [Accepted: 06/09/2023] [Indexed: 07/09/2023]
Abstract
BACKGROUND Sepsis-associated brain dysfunction (SABD) is frequent and is associated with poor outcome. Changes in brain hemodynamics remain poorly described in this setting. The aim of this study was to investigate the alterations of cerebral perfusion pressure and intracranial pressure in a cohort of septic patients. METHODS We conducted a retrospective analysis of prospectively collected data in septic adults admitted to our intensive care unit (ICU). We included patients in whom transcranial Doppler recording performed within 48 h from diagnosis of sepsis was available. Exclusion criteria were intracranial disease, known vascular stenosis, cardiac arrhythmias, pacemaker, mechanical cardiac support, severe hypotension, and severe hypocapnia or hypercapnia. SABD was clinically diagnosed by the attending physician, anytime during the ICU stay. Estimated cerebral perfusion pressure (eCPP) and estimated intracranial pressure (eICP) were calculated from the blood flow velocity of the middle cerebral artery and invasive arterial pressure using a previously validated formula. Normal eCPP was defined as eCPP ≥ 60 mm Hg, low eCPP was defined as eCPP < 60 mm Hg; normal eICP was defined as eICP ≤ 20 mm Hg, and high eICP was defined as eICP > 20 mm Hg. RESULTS A total of 132 patients were included in the final analysis (71% male, median [interquartile range (IQR)] age was 64 [52-71] years, median [IQR] Acute Physiology and Chronic Health Evaluation II score on admission was 21 [15-28]). Sixty-nine (49%) patients developed SABD during the ICU stay, and 38 (29%) were dead at hospital discharge. Transcranial Doppler recording lasted 9 (IQR 7-12) min. Median (IQR) eCPP was 63 (58-71) mm Hg in the cohort; 44 of 132 (33%) patients had low eCPP. Median (IQR) eICP was 8 (4-13) mm Hg; five (4%) patients had high eICP. SABD occurrence and in-hospital mortality did not differ between patients with normal eCPP and patients with low eCPP or between patients with normal eICP and patients with high eICP. Eighty-six (65%) patients had normal eCPP and normal eICP, 41 (31%) patients had low eCPP and normal eICP, three (2%) patients had low eCPP and high eICP, and two (2%) patients had normal eCPP and high eICP; however, SABD occurrence and in-hospital mortality were not significantly different among these subgroups. CONCLUSIONS Brain hemodynamics, in particular CPP, were altered in one third of critically ill septic patients at a steady state of monitoring performed early during the course of sepsis. However, these alterations were equally common in patients who developed or did not develop SABD during the ICU stay and in patients with favorable or unfavorable outcome.
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Affiliation(s)
- Ilaria Alice Crippa
- Department of Intensive Care, Erasme Hospital, Université Libre de Bruxelles (ULB), Route de Lennik 808, 1070, Brussels, Belgium.
- Department of Anesthesiology and Intensive Care, Policlinico San Marco, Gruppo San Donato, Corso Europa 7, 24046, Zingonia, Italy.
| | - Jean-Louis Vincent
- Department of Intensive Care, Erasme Hospital, Université Libre de Bruxelles (ULB), Route de Lennik 808, 1070, Brussels, Belgium
| | - Federica Zama Cavicchi
- Department of Intensive Care, Erasme Hospital, Université Libre de Bruxelles (ULB), Route de Lennik 808, 1070, Brussels, Belgium
| | - Selene Pozzebon
- Department of Intensive Care, Erasme Hospital, Université Libre de Bruxelles (ULB), Route de Lennik 808, 1070, Brussels, Belgium
| | - Nicolas Gaspard
- Department of Neurology, Erasme Hospital, Université Libre de Bruxelles (ULB), Route de Lennik 808, 1070, Brussels, Belgium
| | - Christelle Maenhout
- Department of Neurology, Erasme Hospital, Université Libre de Bruxelles (ULB), Route de Lennik 808, 1070, Brussels, Belgium
| | - Jacques Creteur
- Department of Intensive Care, Erasme Hospital, Université Libre de Bruxelles (ULB), Route de Lennik 808, 1070, Brussels, Belgium
| | - Fabio Silvio Taccone
- Department of Intensive Care, Erasme Hospital, Université Libre de Bruxelles (ULB), Route de Lennik 808, 1070, Brussels, Belgium
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10
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Worley ML, Reed EL, Klaes N, Schlader ZJ, Johnson BD. Cool head-out water immersion does not alter cerebrovascular reactivity to hypercapnia despite elevated middle cerebral artery blood velocity: A pilot study. PLoS One 2024; 19:e0298587. [PMID: 38478550 PMCID: PMC10936844 DOI: 10.1371/journal.pone.0298587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 01/28/2024] [Indexed: 03/24/2024] Open
Abstract
Episodic increases in cerebral blood flow (CBF) are thought to contribute to improved cerebrovascular function and health. Head-out water immersion (HOWI) may be a useful modality to increase CBF secondary to the hydrostatic pressure placed on the body. However, it is unclear whether water temperatures common to the general public elicit similar cerebrovascular responses. We tested the hypothesis that mean middle cerebral artery blood velocity (MCAvmean) and cerebrovascular reactivity to CO2 (CVRCO2) would be higher during an acute bout of thermoneutral (TN; 35°C) vs. cool (COOL; 25°C) HOWI. Ten healthy participants (age: 23±3 y; 4 women) completed two randomized HOWI visits. Right MCAvmean, end-tidal CO2 (PETCO2) mean arterial pressure (MAP), and MCA conductance (MCAvmean/MAP) were continuously recorded. CVRCO2 was assessed using a stepped hypercapnia protocol before (PRE), at 30 minutes of HOWI (HOWI), immediately after HOWI (POST-1), and 45 minutes after HOWI (POST-2). Absolute values are reported as mean ± SD. MCAvmean, PETCO2, MAP, and CVRCO2 were not different between conditions at any timepoint (all P≥0.17). In COOL, MCAvmean increased from PRE (61±9 cm/s) during HOWI (68±11 cm/s), at POST-1 (69±11 cm/s), and POST-2 (72±8 cm/s) (all P<0.01), and in TN from PRE to POST-1 (66±13 vs. 71±14 cm/s; P = 0.05). PETCO2 did not change over time in either condition. In COOL, MAP increased from PRE (85±5 mmHg) during HOWI (101±4 mmHg), at POST-1 (97±7 mmHg), and POST-2 (96±9 mmHg), and in TN from PRE (88±5 mmHg) at HOWI (98±7 mmHg) and POST-1 (99±8 mmHg) (all P<0.01). In COOL, CVRCO2 increased from PRE to HOWI (1.66±0.55 vs. 1.92±0.52 cm/s/mmHg; P = 0.04). MCA conductance was not different between or within conditions. These data indicate that 30 minutes of cool HOWI augments MCAvmean and that the increase in MCAvmean persists beyond cool HOWI. However, cool HOWI does not alter CVRCO2 in healthy young adults.
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Affiliation(s)
- Morgan L. Worley
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, School of Public Health and Health Professions, University at Buffalo, Buffalo, NY, United States of America
| | - Emma L. Reed
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, School of Public Health and Health Professions, University at Buffalo, Buffalo, NY, United States of America
- Department of Human Physiology, College of Arts and Sciences, University of Oregon, Eugene, OR, United States of America
| | - Nathan Klaes
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, School of Public Health and Health Professions, University at Buffalo, Buffalo, NY, United States of America
| | - Zachary J. Schlader
- Department of Kinesiology, School of Public Health-Bloomington, Indiana University, Bloomington, IN, United States of America
| | - Blair D. Johnson
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, School of Public Health and Health Professions, University at Buffalo, Buffalo, NY, United States of America
- Department of Kinesiology, School of Public Health-Bloomington, Indiana University, Bloomington, IN, United States of America
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11
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Caddy HT, Thomas HJ, Kelsey LJ, Smith KJ, Doyle BJ, Green DJ. Comparison of computational fluid dynamics with transcranial Doppler ultrasound in response to physiological stimuli. Biomech Model Mechanobiol 2024; 23:255-269. [PMID: 37805938 PMCID: PMC10902019 DOI: 10.1007/s10237-023-01772-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 09/05/2023] [Indexed: 10/10/2023]
Abstract
Cerebrovascular haemodynamics are sensitive to multiple physiological stimuli that require synergistic response to maintain adequate perfusion. Understanding haemodynamic changes within cerebral arteries is important to inform how the brain regulates perfusion; however, methods for direct measurement of cerebral haemodynamics in these environments are challenging. The aim of this study was to assess velocity waveform metrics obtained using transcranial Doppler (TCD) with flow-conserving subject-specific three-dimensional (3D) simulations using computational fluid dynamics (CFD). Twelve healthy participants underwent head and neck imaging with 3 T magnetic resonance angiography. Velocity waveforms in the middle cerebral artery were measured with TCD ultrasound, while diameter and velocity were measured using duplex ultrasound in the internal carotid and vertebral arteries to calculate incoming cerebral flow at rest, during hypercapnia and exercise. CFD simulations were developed for each condition, with velocity waveform metrics extracted in the same insonation region as TCD. Exposure to stimuli induced significant changes in cardiorespiratory measures across all participants. Measured absolute TCD velocities were significantly higher than those calculated from CFD (P range < 0.001-0.004), and these data were not correlated across conditions (r range 0.030-0.377, P range 0.227-0.925). However, relative changes in systolic and time-averaged velocity from resting levels exhibited significant positive correlations when the distinct techniques were compared (r range 0.577-0.770, P range 0.003-0.049). Our data indicate that while absolute measures of cerebral velocity differ between TCD and 3D CFD simulation, physiological changes from resting levels in systolic and time-averaged velocity are significantly correlated between techniques.
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Affiliation(s)
- Harrison T Caddy
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, Queen Elizabeth II Medical Centre, Nedlands, Australia and the UWA Centre for Medical Research, The University of Western Australia, Perth, Australia
- School of Human Sciences (Exercise and Sport Sciences), The University of Western Australia, Perth, Australia
| | - Hannah J Thomas
- School of Human Sciences (Exercise and Sport Sciences), The University of Western Australia, Perth, Australia
| | - Lachlan J Kelsey
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, Queen Elizabeth II Medical Centre, Nedlands, Australia and the UWA Centre for Medical Research, The University of Western Australia, Perth, Australia
- School of Engineering, The University of Western Australia, Perth, Australia
| | - Kurt J Smith
- School of Human Sciences (Exercise and Sport Sciences), The University of Western Australia, Perth, Australia
- Cerebrovascular Health, Exercise, and Environmental Research Sciences Laboratory, University of Victoria, Victoria, Canada
| | - Barry J Doyle
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, Queen Elizabeth II Medical Centre, Nedlands, Australia and the UWA Centre for Medical Research, The University of Western Australia, Perth, Australia.
- School of Engineering, The University of Western Australia, Perth, Australia.
| | - Daniel J Green
- School of Human Sciences (Exercise and Sport Sciences), The University of Western Australia, Perth, Australia
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12
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Goldstein DS. Linking the Extended Autonomic System with the Homeostat Theory: New Perspectives about Dysautonomias. J Pers Med 2024; 14:123. [PMID: 38276245 PMCID: PMC10817591 DOI: 10.3390/jpm14010123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 01/14/2024] [Accepted: 01/20/2024] [Indexed: 01/27/2024] Open
Abstract
Dysautonomias are conditions in which altered functions of one or more components of the autonomic nervous system (ANS) adversely affect health. This essay is about how elucidating mechanisms of dysautonomias may rationalize personalized treatments. Emphasized here are two relatively new ideas-the "extended" autonomic system (EAS) and the "homeostat" theory as applied to the pathophysiology and potential treatments of dysautonomias. The recently promulgated concept of the EAS updates Langley's ANS to include neuroendocrine, immune/inflammatory, and central components. The homeostat theory builds on Cannon's theory of homeostasis by proposing the existence of comparators (e.g., a thermostat, glucostat, carbistat, barostat) that receive information about regulated variables (e.g., core temperature, blood glucose, blood gases, delivery of blood to the brain). Homeostats sense discrepancies between the information and response algorithms. The presentation links the EAS with the homeostat theory to understand pathophysiological mechanisms of dysautonomias. Feed-forward anticipatory processes shift input-output curves and maintain plateau levels of regulated variables within different bounds of values-"allostasis". Sustained allostatic processes increase long-term wear-and-tear on effectors and organs-allostatic load. They decreaseing thresholds for destabilizing and potentially fatal positive feedback loops. The homeostat theory enables mathematical models that define stress, allostasis, and allostatic load. The present discussion applies the EAS and homeostat concepts to specific examples of pediatric, adolescent/adult, and geriatric dysautonomias-familial dysautonomia, chronic orthostatic intolerance, and Lewy body diseases. Computer modeling has the potential to take into account the complexity and dynamics of allostatic processes and may yield testable predictions about individualized treatments and outcomes.
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Affiliation(s)
- David S Goldstein
- Autonomic Medicine Section, Clinical Neurosciences Program, Division of Intramural Research, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
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13
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Samaras A, Papazoglou AS, Balomenakis C, Bekiaridou A, Moysidis DV, Patsiou V, Orfanidis A, Giannakoulas G, Kassimis G, Fragakis N, Saw J, Landmesser U, Alkhouli MA, Tzikas A. Residual leaks following percutaneous left atrial appendage occlusion and outcomes: a meta-analysis. Eur Heart J 2024; 45:214-229. [PMID: 38088437 DOI: 10.1093/eurheartj/ehad828] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 10/02/2023] [Accepted: 10/19/2023] [Indexed: 01/15/2024] Open
Abstract
BACKGROUND AND AIMS Residual leaks are not infrequent after left atrial appendage occlusion. However, there is still uncertainty regarding their prognostic implications. The aim of this study is to evaluate the impact of residual leaks after left atrial appendage occlusion. METHODS A literature search was conducted until 19 February 2023. Residual leaks comprised peri-device leaks (PDLs) on transoesophageal echocardiography (TEE) or computed tomography (CT), as well as left atrial appendage patency on CT. Random-effects meta-analyses were performed to assess the clinical impact of residual leaks. RESULTS Overall 48 eligible studies (44 non-randomized/observational and 4 randomized studies) including 61 666 patients with atrial fibrillation who underwent left atrial appendage occlusion were analysed. Peri-device leak by TEE was present in 26.1% of patients. Computed tomography-based left atrial appendage patency and PDL were present in 54.9% and 57.3% of patients, respectively. Transoesophageal echocardiography-based PDL (i.e. any reported PDL regardless of its size) was significantly associated with a higher risk of thromboembolism [pooled odds ratio (pOR) 2.04, 95% confidence interval (CI): 1.52-2.74], all-cause mortality (pOR 1.16, 95% CI: 1.08-1.24), and major bleeding (pOR 1.12, 95% CI: 1.03-1.22), compared with no reported PDL. A positive graded association between PDL size and risk of thromboembolism was noted across TEE cut-offs. For any PDL of >0, >1, >3, and >5 mm, the pORs for thromboembolism were 1.82 (95% CI: 1.35-2.47), 2.13 (95% CI: 1.04-4.35), 4.14 (95% CI: 2.07-8.27), and 4.44 (95% CI: 2.09-9.43), respectively, compared with either no PDL or PDL smaller than each cut-off. Neither left atrial appendage patency, nor PDL by CT was associated with thromboembolism (pOR 1.45 and 1.04, 95% CI: 0.84-2.50 and 0.52-2.07, respectively). CONCLUSIONS Peri-device leak detected by TEE was associated with adverse events, primarily thromboembolism. Residual leaks detected by CT were more frequent but lacked prognostic significance.
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Affiliation(s)
- Athanasios Samaras
- Second Department of Cardiology, Faculty of Health Sciences, School of Medicine, General Hospital 'Hippokration', Aristotle University of Thessaloniki, Konstantinoupoleos 49, Thessaloniki 54642, Greece
| | - Andreas S Papazoglou
- Faculty of Health Sciences, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Charalampos Balomenakis
- Faculty of Health Sciences, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Alexandra Bekiaridou
- Faculty of Health Sciences, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | - Dimitrios V Moysidis
- Second Department of Cardiology, Faculty of Health Sciences, School of Medicine, General Hospital 'Hippokration', Aristotle University of Thessaloniki, Konstantinoupoleos 49, Thessaloniki 54642, Greece
- Faculty of Health Sciences, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Vasiliki Patsiou
- Faculty of Health Sciences, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
- First Department of Cardiology, Faculty of Health Sciences, School of Medicine, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Antonios Orfanidis
- Faculty of Health Sciences, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - George Giannakoulas
- First Department of Cardiology, Faculty of Health Sciences, School of Medicine, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - George Kassimis
- Second Department of Cardiology, Faculty of Health Sciences, School of Medicine, General Hospital 'Hippokration', Aristotle University of Thessaloniki, Konstantinoupoleos 49, Thessaloniki 54642, Greece
| | - Nikolaos Fragakis
- Second Department of Cardiology, Faculty of Health Sciences, School of Medicine, General Hospital 'Hippokration', Aristotle University of Thessaloniki, Konstantinoupoleos 49, Thessaloniki 54642, Greece
| | - Jacqueline Saw
- Division of Cardiology, Vancouver General Hospital, University of British Columbia, Vancouver, Canada
| | - Ulf Landmesser
- Department of Cardiology, Charité Universitätsmedizin, Berlin, Germany
| | | | - Apostolos Tzikas
- Second Department of Cardiology, Faculty of Health Sciences, School of Medicine, General Hospital 'Hippokration', Aristotle University of Thessaloniki, Konstantinoupoleos 49, Thessaloniki 54642, Greece
- European Interbalkan Medical Center, Department of Cardiology, Asklipiou 10, Pylaia, Thessaloniki 57001, Greece
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14
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Li N, Zhou F, Lu X, Chen H, Liu R, Chen S, Xing Y. Impaired Dynamic Cerebral Autoregulation as a Predictor for Cerebral Hyperperfusion After Carotid Endarterectomy: A Prospective Observational Study. World Neurosurg 2024; 181:e312-e321. [PMID: 37838165 DOI: 10.1016/j.wneu.2023.10.046] [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: 08/20/2023] [Revised: 10/08/2023] [Accepted: 10/08/2023] [Indexed: 10/16/2023]
Abstract
OBJECTIVE Cerebral hyperperfusion syndrome (CHS) is a severe complication of carotid endarterectomy (CEA). Because cerebral hyperperfusion (CH) reduces the benefits of CEA, it is important to identify patients at high risk of developing CH. We investigated dynamic cerebral autoregulation (dCA) as a potential predictor of CH after CEA. METHODS In a prospective observational study of 90 patients, we defined CH as a ≥100% increase in the transcranial Doppler ultrasound-derived mean flow velocity of the middle cerebral artery compared to baseline, with or without clinical manifestations. We examined dCA in the supine position and during squat-stand maneuvers using the transfer function, analyzing phase, gain, and coherence. Logistic regression analysis and receiver operating characteristic (ROC) curves were used to assess the relationships between variables and outcomes. RESULTS Cerebral hyperperfusion (CH) occurred in 18 patients after CEA. The CH group had a lower ipsilateral phase for both body postures than the non-CH group at very low and low frequencies, respectively (both P < 0.01). Postoperative CH was independently associated with the preoperative peak systolic velocity (PSV)sten/PSVdis ratio and the ipsilateral phase in both body postures at a very low frequency. Receiver operating characteristic (ROC) curve analysis showed that the ipsilateral phase had excellent CH predictive accuracy in the supine position and squat-stand maneuvers at a very low frequency (areas under the curve: 0.809 and 0.839, respectively, both P < 0.001; cutoff values: 24.7 and 11.7, respectively). CONCLUSIONS The lower ipsilateral phase may serve as a predictor of CH after CEA.
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Affiliation(s)
- Na Li
- Department of Vascular Ultrasonography, Xuanwu Hospital, Capital Medical University, Beijing, China; Beijing Diagnostic Center of Vascular Ultrasound, Beijing, China; Center of Vascular Ultrasonography, Beijing Institute of Brain Disorders, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
| | - Fubo Zhou
- Department of Vascular Ultrasonography, Xuanwu Hospital, Capital Medical University, Beijing, China; Beijing Diagnostic Center of Vascular Ultrasound, Beijing, China; Center of Vascular Ultrasonography, Beijing Institute of Brain Disorders, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
| | - Xia Lu
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Hongxiu Chen
- Department of Vascular Ultrasonography, Xuanwu Hospital, Capital Medical University, Beijing, China; Beijing Diagnostic Center of Vascular Ultrasound, Beijing, China; Center of Vascular Ultrasonography, Beijing Institute of Brain Disorders, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
| | - Ran Liu
- Department of Vascular Ultrasonography, Xuanwu Hospital, Capital Medical University, Beijing, China; Beijing Diagnostic Center of Vascular Ultrasound, Beijing, China; Center of Vascular Ultrasonography, Beijing Institute of Brain Disorders, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
| | - Songwei Chen
- Department of Vascular Ultrasonography, Xuanwu Hospital, Capital Medical University, Beijing, China; Beijing Diagnostic Center of Vascular Ultrasound, Beijing, China; Center of Vascular Ultrasonography, Beijing Institute of Brain Disorders, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
| | - Yingqi Xing
- Department of Vascular Ultrasonography, Xuanwu Hospital, Capital Medical University, Beijing, China; Beijing Diagnostic Center of Vascular Ultrasound, Beijing, China; Center of Vascular Ultrasonography, Beijing Institute of Brain Disorders, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China.
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15
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Skinner BD, Lucas RAI, Lucas SJE. Exposure to passive heat and cold stress differentially modulates cerebrovascular-CO 2 responsiveness. J Appl Physiol (1985) 2024; 136:23-32. [PMID: 37969086 DOI: 10.1152/japplphysiol.00494.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 10/30/2023] [Accepted: 11/13/2023] [Indexed: 11/17/2023] Open
Abstract
Heat and cold stress influence cerebral blood flow (CBF) regulatory factors (e.g., arterial CO2 partial pressure). However, it is unclear whether the CBF response to a CO2 stimulus (i.e., cerebrovascular-CO2 responsiveness) is maintained under different thermal conditions. This study aimed to compare cerebrovascular-CO2 responsiveness between normothermia, passive heat, and cold stress conditions. Sixteen participants (8 females; 25 ± 7 yr) completed two experimental sessions (randomized) comprising normothermic and either passive heat or cold stress conditions. Middle and posterior cerebral artery velocity (MCAv, PCAv) were measured during rest, hypercapnia (5% CO2 inhalation), and hypocapnia (voluntary hyperventilation to an end-tidal CO2 of 30 mmHg). The linear slope of the cerebral blood velocity (CBv) response to changing end-tidal CO2 was calculated to measure cerebrovascular-CO2 responsiveness, and cerebrovascular conductance (CVC) was used to examine responsiveness independent of blood pressure. CBv-CVC-CO2 responsiveness to hypocapnia was greater during heat stress compared with cold stress (MCA: +0.05 ± 0.08 cm/s/mmHg/mmHg, P = 0.04; PCA: +0.02 ± 0.02 cm/s/mmHg/mmHg, P = 0.002). CBv-CO2 responsiveness to hypercapnia decreased during heat stress (MCA: -0.67 ± 0.89 cm/s/mmHg, P = 0.02; PCA: -0.64 ± 0.62 cm/s/mmHg; P = 0.01) and increased during cold stress (MCA: +0.98 ± 1.33 cm/s/mmHg, P = 0.03; PCA: +1.00 ± 0.82 cm/s/mmHg; P = 0.01) compared with normothermia. However, CBv-CVC-CO2 responsiveness to hypercapnia was not different between thermal conditions (P > 0.08). Overall, passive heat, but not cold, stress challenges the maintenance of cerebral perfusion. A greater cerebrovascular responsiveness to hypocapnia during heat stress likely reduces an already impaired cerebrovascular reserve capacity and may contribute to adverse events (e.g., syncope).NEW & NOTEWORTHY This study demonstrates that thermoregulatory-driven perfusion pressure changes, from either cold or heat stress, impact cerebrovascular responsiveness to hypercapnia. Compared with cold stress, heat stress poses a greater challenge to the maintenance of cerebral perfusion during hypocapnia, challenging cerebrovascular reserve capacity while increasing cerebrovascular-CO2 responsiveness. This likely exacerbates cerebral hypoperfusion during heat stress since hyperthermia-induced hyperventilation results in hypocapnia. No regional differences in middle and posterior cerebral artery responsiveness were found with thermal stress.
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Affiliation(s)
- Bethany D Skinner
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Rebekah A I Lucas
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Samuel J E Lucas
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
- Centre for Human Brain Health, University of Birmingham, Birmingham, United Kingdom
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16
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Brassard P, Roy MA, Burma JS, Labrecque L, Smirl JD. Quantification of dynamic cerebral autoregulation: welcome to the jungle! Clin Auton Res 2023; 33:791-810. [PMID: 37758907 DOI: 10.1007/s10286-023-00986-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 09/11/2023] [Indexed: 09/29/2023]
Abstract
PURPOSE Patients with dysautonomia often experience symptoms such as dizziness, syncope, blurred vision and brain fog. Dynamic cerebral autoregulation, or the ability of the cerebrovasculature to react to transient changes in arterial blood pressure, could be associated with these symptoms. METHODS In this narrative review, we go beyond the classical view of cerebral autoregulation to discuss dynamic cerebral autoregulation, focusing on recent advances pitfalls and future directions. RESULTS Following some historical background, this narrative review provides a brief overview of the concept of cerebral autoregulation, with a focus on the quantification of dynamic cerebral autoregulation. We then discuss the main protocols and analytical approaches to assess dynamic cerebral autoregulation, including recent advances and important issues which need to be tackled. CONCLUSION The researcher or clinician new to this field needs an adequate comprehension of the toolbox they have to adequately assess, and interpret, the complex relationship between arterial blood pressure and cerebral blood flow in healthy individuals and clinical populations, including patients with autonomic disorders.
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Affiliation(s)
- Patrice Brassard
- Department of Kinesiology, Faculty of Medicine, Université Laval, Québec, Canada.
- Research center of the Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Canada.
| | - Marc-Antoine Roy
- Department of Kinesiology, Faculty of Medicine, Université Laval, Québec, Canada
- Research center of the Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Canada
| | - Joel S Burma
- Cerebrovascular Concussion Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
- Sport Injury Prevention Research Centre, Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
- Integrated Concussion Research Program, University of Calgary, Calgary, AB, Canada
- Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
| | - Lawrence Labrecque
- Department of Kinesiology, Faculty of Medicine, Université Laval, Québec, Canada
- Research center of the Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Canada
| | - Jonathan D Smirl
- Cerebrovascular Concussion Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
- Sport Injury Prevention Research Centre, Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
- Integrated Concussion Research Program, University of Calgary, Calgary, AB, Canada
- Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
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17
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Abdali K, Chen X, Ross S, Davis S, Zhou Z, Mallet RT, Shi X. Mechanisms maintaining cerebral perfusion during systemic hypotension are impaired in elderly adults. Exp Biol Med (Maywood) 2023; 248:2464-2472. [PMID: 38057956 PMCID: PMC10903242 DOI: 10.1177/15353702231209416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 09/11/2023] [Indexed: 12/08/2023] Open
Abstract
Postural hypotension abruptly lowers cerebral perfusion, producing unsteadiness which worsens with aging. This study addressed the hypothesis that maintenance of cerebral perfusion weakens in the elderly due to less effective cerebrovascular autoregulation and systemic cardiovascular responses to hypotension. In healthy elderly (n = 13, 68 ± 1 years) and young (n = 13, 26 ± 1 years) adults, systemic hypotension was induced by rapid deflation of bilateral thigh cuffs after 3-min suprasystolic occlusion, while heart rate (HR), mean arterial pressure (MAP), and blood flow velocity of the middle cerebral artery (VMCA) were recorded. VMCA/MAP indexed cerebrovascular conductance (CVC). Durations and rates of recovery of MAP and VMCA from their respective postdeflation nadirs were compared between the groups. Thigh-cuff deflation elicited similar hypotension and cerebral hypoperfusion in the elderly and young adults. However, the time elapsed (TΔ) from cuff deflation to the nadirs of MAP and VMCA, and the time for full recovery (TR) from nadirs to baselines were significantly prolonged in the elderly subjects. The response rates of HR (ΔHR, i.e. cardiac factor), MAP (ΔMAP, i.e. vasomotor factor), and CVC following cuff deflation were significantly slower in the elderly. Collectively, the response rates of the cardiac, vasomotor, and CVC factors largely explained TRVMCA. However, the TRVMCA/ΔMAP slope (-3.0 ± 0.9) was steeper (P = 0.046) than the TRVMCA/ΔHR slope (-1.1 ± 0.4). The TRVMCA/ΔCVC slope (-2.4 ± 0.6) was greater (P = 0.072) than the TRVMCA/ΔHR slope, but did not differ from the TRVMCA/ΔMAP slope (P = 0.52). Both cerebrovascular autoregulatory and systemic mechanisms contributed to cerebral perfusion recovery during systemic hypotension, and the vasomotor factor was predominant over the cardiac factor. Recovery from cerebral hypoperfusion was slower in the elderly adults because of the age-diminished rates of the CVC response and cardiovascular reflex regulation. Systemic vasoconstriction predominated over increased HR for restoring cerebral perfusion after abrupt onset of systemic hypotension.
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Affiliation(s)
- Kulsum Abdali
- Departments of Pharmacology and Neuroscience, The University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Xiaoan Chen
- Departments of Pharmacology and Neuroscience, The University of North Texas Health Science Center, Fort Worth, TX 76107, USA
- Jishou University, Jishou 416000, China
| | - Sarah Ross
- Departments of Internal Medicine, The University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Sandra Davis
- Departments of Internal Medicine, The University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Zhengyang Zhou
- Departments of Biostatistics & Epidemiology, The University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Robert T Mallet
- Departments of Physiology and Anatomy, The University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Xiangrong Shi
- Departments of Pharmacology and Neuroscience, The University of North Texas Health Science Center, Fort Worth, TX 76107, USA
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18
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Zhang A, Mandeville ET, Xu L, Stary CM, Lo EH, Lieber CM. Ultraflexible endovascular probes for brain recording through micrometer-scale vasculature. Science 2023; 381:306-312. [PMID: 37471542 PMCID: PMC11412271 DOI: 10.1126/science.adh3916] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 05/19/2023] [Indexed: 07/22/2023]
Abstract
Implantable neuroelectronic interfaces have enabled advances in both fundamental research and treatment of neurological diseases but traditional intracranial depth electrodes require invasive surgery to place and can disrupt neural networks during implantation. We developed an ultrasmall and flexible endovascular neural probe that can be implanted into sub-100-micrometer-scale blood vessels in the brains of rodents without damaging the brain or vasculature. In vivo electrophysiology recording of local field potentials and single-unit spikes have been selectively achieved in the cortex and olfactory bulb. Histology analysis of the tissue interface showed minimal immune response and long-term stability. This platform technology can be readily extended as both research tools and medical devices for the detection and intervention of neurological diseases.
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Affiliation(s)
- Anqi Zhang
- Department of Chemical Engineering and Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Emiri T Mandeville
- Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Boston, MA 02129, USA
| | - Lijun Xu
- Department of Anesthesiology, Perioperative & Pain Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Creed M Stary
- Department of Anesthesiology, Perioperative & Pain Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Eng H Lo
- Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Boston, MA 02129, USA
| | - Charles M Lieber
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
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19
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Stewart JM, Medow MS. Anticipatory central command on standing decreases cerebral blood velocity causing hypocapnia in hyperpneic postural tachycardia syndrome. J Appl Physiol (1985) 2023; 135:26-34. [PMID: 37227184 PMCID: PMC10281786 DOI: 10.1152/japplphysiol.00016.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 05/16/2023] [Accepted: 05/18/2023] [Indexed: 05/26/2023] Open
Abstract
Fifty percent of patients with postural tachycardia syndrome (POTS) are hypocapnic during orthostasis related to initial orthostatic hypotension (iOH). We determined whether iOH drives hypocapnia in POTS by low BP or decreased cerebral blood velocity (CBv). We studied three groups; healthy volunteers (n = 32, 18 ± 3 yr) were compared with POTS, grouped by presence [POTS-low end-tidal CO2 (↓ETCO2), n = 26, 19 ± 2 yr] or absence [POTS-normal upright end-tidal carbon dioxide (nlCO2), n = 28, 19 ± 3 yr] of standing hypocapnia defined by end-tidal CO2 (ETCO2) ≤ 30 mmHg at steady-state, measuring middle cerebral artery CBv, heart rate (HR), and beat-to-beat blood pressure (BP). After 30 min supine, subjects stood for 5 min. Quantities were measured prestanding, at minimum CBv, minimum BP, peak HR, CBv recovery, BP recovery, minimum HR, steady-state, and 5 min. Baroreflex gain was estimated by α index. iOH occurred with similar frequency and minimum BP in POTS-↓ETCO2 and POTS-nlCO2. Minimum CBv was reduced significantly (P < 0.05) in POTS-↓ETCO2 (48 ± 3 cm/s) preceding hypocapnia compared with POTS-nlCO2 (61 ± 3 cm/s) or Control (60 ± 2 cm/s). The anticipatory increased BP was significantly larger (P < 0.05) in POTS (8 ± 1 mmHg vs. 2 ± 1) and began ∼8 s prestanding. HR increased in all subjects, CBv increased significantly (P < 0.05) in both POTS-nlCO2 (76 ± 2 to 85 ± 2 cm/s) and Control (75 ± 2 to 80 ± 2 cm/s) consistent with central command. CBv decreased in POTS-↓ETCO2 (76 ± 3 to 64 ± 3 cm/s) correlating with decreased baroreflex gain. Cerebral conductance [meanCBv/mean arterial blood pressure (MAP)] was reduced in POTS-↓ETCO2 throughout. Data support the hypothesis that excessively reduced CBv during iOH may intermittently reduce carotid body blood flow, sensitizing that organ and producing postural hyperventilation in POTS-↓ETCO2. Excessive fall in CBv occurs in part during prestanding central command and is a facet of defective parasympathetic regulation in POTS.NEW & NOTEWORTHY Dyspnea is frequent in postural tachycardia syndrome (POTS) and is associated with upright hyperpnea and hypocapnia that drives sinus tachycardia. It is initiated by an exaggerated reduction in cerebral conductance and decreased cerebral blood flow (CBF) that precedes the act of standing. This is a form of autonomically mediated "central command." Cerebral blood flow is further reduced by initial orthostatic hypotension common in POTS. Hypocapnia is maintained during the standing response and might account for persistent postural tachycardia.
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Affiliation(s)
- Julian M Stewart
- Department of Pediatrics, New York Medical College, Valhalla, New York, United States
- Department of Physiology, New York Medical College, Valhalla, New York, United States
| | - Marvin S Medow
- Department of Pediatrics, New York Medical College, Valhalla, New York, United States
- Department of Physiology, New York Medical College, Valhalla, New York, United States
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20
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Nzulumike ANO, Thormann E. Fibrin Adsorption on Cardiovascular Biomaterials and Medical Devices. ACS APPLIED BIO MATERIALS 2023. [PMID: 37368548 DOI: 10.1021/acsabm.2c01057] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/29/2023]
Abstract
Medical devices that are inserted in blood vessels always risk eliciting thrombosis, and the surface properties of such devices are thus of major importance. The initiating step for surface-induced pathological coagulation has been associated with adsorption of fibrinogen protein on biomaterial surfaces and subsequent polymerization into an insoluble fibrin clot. This issue gives rise to an inherent challenge in biomaterial design as varied surface materials must fulfill specialized roles while also minimizing thrombotic complications from spontaneous fibrin(ogen) recruitment. We have aimed to characterize the thrombogenic properties of state-of-the-art cardiovascular biomaterials and medical devices by quantifying the relative surface-dependent adsorption and formation of fibrin followed by analysis of the resulting morphologies. We identified stainless steel and amorphous fluoropolymer as comparatively preferable biomaterials based on their low fibrin(ogen) recruitment, in comparison to other metallic and polymeric biomaterials, respectively. In addition, we observed a morphological trend that fibrin forms fiber structures on metallic surfaces and fractal branched structures on polymeric surfaces. Finally, we used vascular guidewires as clotting substrates and found that fibrin adsorption depends on parts of the guidewire that are exposed, and we correlated the morphologies on uncoated guidewires with those formed on raw stainless-steel biomaterials.
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Affiliation(s)
- Achebe N O Nzulumike
- Department of Chemistry, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
- Department of Civil and Mechanical Engineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Esben Thormann
- Department of Chemistry, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
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21
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Urvi S, Suman V, Subathra A. Assessment of morphometric parameters of middle cerebral artery using CT angiography in a tertiary care hospital. Surg Radiol Anat 2023:10.1007/s00276-023-03148-1. [PMID: 37269412 DOI: 10.1007/s00276-023-03148-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Accepted: 04/12/2023] [Indexed: 06/05/2023]
Abstract
PURPOSE Middle cerebral artery (MCA) favors secondaries and emboli deposition. Also, with an increase in incidence of MCA aneurysms, majorly at the M1 division point, actual standardized measurement of MCA is necessary. Thus, main aim of the study is assessment of the MCA morphometry using CT Angiography in Indian population. METHODS CT cerebral Angiography datasets of 289 patients (180 males and 109 females) were assessed for the MCA morphometry (Average age - 49.29 ± 16.16 years, Range- 11 to 85 years). The cases involving aneurysms and infarcts were excluded. The total length of MCA, length of M1 segment and diameter were measured and the results were statistically analysed. RESULTS The mean total length of MCA, length of M1 segment and diameter were 24.02 ± 1.22 mm, 14.32 ± 1.27 mm, 3.33 ± 0.62 mm, respectively. The mean length of M1 segment on the right and left sides was 14.19 ± 1.39 mm and 14.44 ± 1.12 mm, respectively and the difference was statistically significant (p ≤ 0.05). The mean diameter on the right and left sides was 3.32 ± 0.62 mm and 3.33 ± 0.62 mm, respectively and the difference was not statistically significant (p = 0.832). The M1 segment length was maximum in patients over 60 years and diameter was maximum in young patients (20-40 years). The mean length of M1 segment in early bifurcation (4.4 ± 0.65 mm), bifurcation (14.32 ± 1.27 mm) and trifurcation (14.15 ± 1.43 mm) was also noted. CONCLUSION The MCA measurements will be useful for surgeons to minimize errors in handling cases of intracranial aneurysms or infarcts and provide the best possible outcome to the patients.
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Affiliation(s)
- Sharma Urvi
- Department of Anatomy, AIIMS Raipur, Raipur, Chhattisgarh, India.
| | - Verma Suman
- Department of Anatomy, JIPMER, Puducherry, India
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22
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Washio T, Hissen SL, Takeda R, Manabe K, Akins JD, Sanchez B, D'Souza AW, Nelson DB, Khan S, Tomlinson AR, Babb TG, Fu Q. Effects of posture changes on dynamic cerebral autoregulation during early pregnancy in women with obesity and/or sleep apnea. Clin Auton Res 2023; 33:121-131. [PMID: 37115467 PMCID: PMC11384342 DOI: 10.1007/s10286-023-00939-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 03/28/2023] [Indexed: 04/29/2023]
Abstract
The incidence of syncope during orthostasis increases in early human pregnancy, which may be associated with cerebral blood flow (CBF) dysregulation in the upright posture. In addition, obesity and/or sleep apnea per se may influence CBF regulation due to their detrimental impacts on cerebrovascular function. However, it is unknown whether early pregnant women with obesity and/or sleep apnea could have impaired CBF regulation in the supine position and whether this impairment would be further exacerbated in the upright posture. Dynamic cerebral autoregulation (CA) was evaluated using transfer function analysis in 33 women during early pregnancy (13 with obesity, 8 with sleep apnea, 12 with normal weight) and 15 age-matched nonpregnant women during supine rest. Pregnant women also underwent a graded head-up tilt (30° and 60° for 6 min each). We found that pregnant women with obesity or sleep apnea had a higher transfer function low-frequency gain compared with nonpregnant women in the supine position (P = 0.026 and 0.009, respectively) but not normal-weight pregnant women (P = 0.945). Conversely, the transfer function low-frequency phase in all pregnancy groups decreased during head-up tilt (P = 0.001), but the phase was not different among pregnant groups (P = 0.180). These results suggest that both obesity and sleep apnea may have a detrimental effect on dynamic CA in the supine position during early pregnancy. CBF may be more vulnerable to spontaneous blood pressure fluctuations in early pregnant women during orthostatic stress compared with supine rest due to less efficient dynamic CA, regardless of obesity and/or sleep apnea.
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Affiliation(s)
- Takuro Washio
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, 7232 Greenville Avenue, Dallas, TX, 75231, USA
- The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Sarah L Hissen
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, 7232 Greenville Avenue, Dallas, TX, 75231, USA
- The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Ryosuke Takeda
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, 7232 Greenville Avenue, Dallas, TX, 75231, USA
- The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Kazumasa Manabe
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, 7232 Greenville Avenue, Dallas, TX, 75231, USA
- The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - John D Akins
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, 7232 Greenville Avenue, Dallas, TX, 75231, USA
- The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Belinda Sanchez
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, 7232 Greenville Avenue, Dallas, TX, 75231, USA
| | - Andrew W D'Souza
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, 7232 Greenville Avenue, Dallas, TX, 75231, USA
- The University of Texas Southwestern Medical Center, Dallas, TX, USA
- Neurovascular Research Laboratory, School of Kinesiology, Western University, London, ON, Canada
| | - David B Nelson
- The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Safia Khan
- The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Andrew R Tomlinson
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, 7232 Greenville Avenue, Dallas, TX, 75231, USA
- The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Tony G Babb
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, 7232 Greenville Avenue, Dallas, TX, 75231, USA
- The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Qi Fu
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, 7232 Greenville Avenue, Dallas, TX, 75231, USA.
- The University of Texas Southwestern Medical Center, Dallas, TX, USA.
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23
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Zhang A, Mandeville ET, Xu L, Stary CM, Lo EH, Lieber CM. Ultra-flexible endovascular probes for brain recording through micron-scale vasculature. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.20.533576. [PMID: 36993229 PMCID: PMC10055285 DOI: 10.1101/2023.03.20.533576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Implantable neuroelectronic interfaces have enabled significant advances in both fundamental research and treatment of neurological diseases, yet traditional intracranial depth electrodes require invasive surgery to place and can disrupt the neural networks during implantation. To address these limitations, we have developed an ultra-small and flexible endovascular neural probe that can be implanted into small 100-micron scale blood vessels in the brains of rodents without damaging the brain or vasculature. The structure and mechanical properties of the flexible probes were designed to meet the key constraints for implantation into tortuous blood vessels inaccessible with existing techniques. In vivo electrophysiology recording of local field potentials and single-unit spikes has been selectively achieved in the cortex and the olfactory bulb. Histology analysis of the tissue interface showed minimal immune response and long-term stability. This platform technology can be readily extended as both research tools and medical devices for the detection and intervention of neurological diseases.
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24
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Ogoh S, Watanabe H, Saito S, Fisher JP, Iwamoto E. Can Alterations in Cerebrovascular CO 2 Reactivity Be Identified Using Transfer Function Analysis without the Requirement for Carbon Dioxide Inhalation? J Clin Med 2023; 12:jcm12062441. [PMID: 36983441 PMCID: PMC10051076 DOI: 10.3390/jcm12062441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 03/09/2023] [Accepted: 03/21/2023] [Indexed: 03/30/2023] Open
Abstract
The present study aimed to examine the validity of a novel method to assess cerebrovascular carbon dioxide (CO2) reactivity (CVR) that does not require a CO2 inhalation challenge, e.g., for use in patients with respiratory disease or the elderly, etc. In twenty-one healthy participants, CVR responses to orthostatic stress (50° head-up tilt, HUT) were assessed using two methods: (1) the traditional CO2 inhalation method, and (2) transfer function analysis (TFA) between middle cerebral artery blood velocity (MCA V) and predicted arterial partial pressure of CO2 (PaCO2) during spontaneous respiration. During HUT, MCA V steady-state (i.e., magnitude) and MCA V onset (i.e., time constant) responses to CO2 inhalation were decreased (p < 0.001) and increased (p = 0.001), respectively, indicative of attenuated CVR. In contrast, TFA gain in the very low-frequency range (VLF, 0.005-0.024 Hz) was unchanged, while the TFA phase in the VLF approached zero during HUT (-0.38 ± 0.59 vs. 0.31 ± 0.78 radians, supine vs. HUT; p = 0.003), indicative of a shorter time (i.e., improved) response of CVR. These findings indicate that CVR metrics determined by TFA without a CO2 inhalation do not track HUT-evoked reductions in CVR identified using CO2 inhalation, suggesting that enhanced cerebral blood flow response to a change in CO2 using CO2 inhalation is necessary to assess CVR adequately.
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Affiliation(s)
- Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, Kawagoe 350-8585, Japan
- Neurovascular Research Laboratory, University of South Wales, Pontypridd CF37 1DL, UK
| | - Hironori Watanabe
- Department of Biomedical Engineering, Toyo University, Kawagoe 350-8585, Japan
| | - Shotaro Saito
- Department of Biomedical Engineering, Toyo University, Kawagoe 350-8585, Japan
| | - James P Fisher
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland 1023, New Zealand
| | - Erika Iwamoto
- School of Health Sciences, Sapporo Medical University, Sapporo 060-8556, Japan
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25
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The benefits of regular aerobic exercise training on cerebrovascular function and cognition in older adults. Eur J Appl Physiol 2023; 123:1323-1342. [PMID: 36801969 PMCID: PMC9938957 DOI: 10.1007/s00421-023-05154-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 02/06/2023] [Indexed: 02/23/2023]
Abstract
We compared the differences in cerebrovascular and cognitive function between 13 aerobic exercise trained, older adults and 13 age-, height- and sex-matched sedentary, untrained controls. We determined whether other measures accounted for differences in cerebrovascular and cognitive function between these groups and examined the associations between these functions. Participants undertook anthropometric, mood, cardiovascular, exercise performance, strength, cerebrovascular, and cognitive measurements, and a blood collection. Transcranial Doppler ultrasonography determined cerebrovascular responsiveness (CVR) to hypercapnia and cognitive stimuli. The trained group had a higher CVR to hypercapnia (80.3 ± 7.2 vs 35.1 ± 6.7%, P < 0.001), CVR to cognitive stimuli (30.1 ± 2.9 vs 17.8 ± 1.4%, P = 0.001) and total composite cognitive score (117 ± 2 vs 98 ± 4, P < 0.001) than the controls. These parameters no longer remained statistically different between the groups following adjustments for covariates. There were positive correlations between the total composite cognitive score and CVR to hypercapnia (r = 0.474, P = 0.014) and CVR to cognitive stimuli (r = 0.685, P < 0.001). We observed a relationship between cerebrovascular and cognitive function in older adults and an interaction between regular lifelong aerobic exercise training and cardiometabolic factors that may directly influence these functions.
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Soejima T, Ueda K, Hasegawa S, Motoe H, Okada K, Ito YM, Hoshino K, Morimoto Y. Change in cerebral circulation during the induction of anesthesia with remimazolam. J Anesth 2023; 37:92-96. [PMID: 36355203 DOI: 10.1007/s00540-022-03135-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Accepted: 10/30/2022] [Indexed: 11/12/2022]
Abstract
PURPOSE Remimazolam is a new ultra-short-acting benzodiazepine with unknown effects on cerebral circulation. We measured total cerebral hemoglobin concentrations, which reflect cerebral blood volume (CBV), and cerebral oxygen saturation, using time-domain near-infrared spectroscopy, which can measure the absolute values of cerebral hemoglobin concentrations. We also measured cerebral blood flow velocity (CBFV) in the middle cerebral artery using transcranial Doppler as an indicator of cerebral blood flow (CBF). We did so to examine the effect of remimazolam on cerebral circulation in humans, as assessed CBV, CBF, and cerebral oxygen saturation. METHODS This was a prospective, observational study. Fifteen patients without serious complications scheduled for general anesthesia were recruited. We measured total cerebral hemoglobin concentrations, CBFV, and cerebral oxygen saturation throughout the anesthetic induction course with remimazolam. RESULTS Total cerebral hemoglobin concentrations did not change during the process (p = 0.51). In contrast, the mean CBFV was reduced by 11% (significant, p = 0.04). The drop in mean blood pressure following the induction of anesthesia was 17%; however, it was within the range of cerebrovascular autoregulation. Moreover, cerebral oxygen saturation increased by 4% (statistically significant, p < 0.01). CONCLUSIONS We found that anesthetic induction with remimazolam did not alter CBV and reduced CBF in uncomplicated patients.
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Affiliation(s)
- Takashi Soejima
- Department of Anesthesiology, Hokkaido University Hospital, N14, W5, Kita-Ku, Sapporo, 060-8648, Japan.
| | - Kentaro Ueda
- Department of Anesthesiology, Hokkaido University Hospital, N14, W5, Kita-Ku, Sapporo, 060-8648, Japan
| | - Sakae Hasegawa
- Department of Anesthesiology, Hokkaido University Hospital, N14, W5, Kita-Ku, Sapporo, 060-8648, Japan
| | - Hiromitsu Motoe
- Department of Anesthesiology, Hokkaido University Hospital, N14, W5, Kita-Ku, Sapporo, 060-8648, Japan
| | - Kazufumi Okada
- Data Science Center, Promotion Unit, Institute of Health Science Innovation for Medical Care, Hokkaido University Hospital, Sapporo, Japan
| | - Yoichi M Ito
- Data Science Center, Promotion Unit, Institute of Health Science Innovation for Medical Care, Hokkaido University Hospital, Sapporo, Japan
| | - Koji Hoshino
- Department of Anesthesiology, Hokkaido University Hospital, N14, W5, Kita-Ku, Sapporo, 060-8648, Japan
| | - Yuji Morimoto
- Department of Anesthesiology, Hokkaido University Hospital, N14, W5, Kita-Ku, Sapporo, 060-8648, Japan
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27
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Skinner BD, Weaver SRC, Lucas SJE, Lucas RAI. Menstrual phase influences cerebrovascular responsiveness in females but may not affect sex differences. Front Physiol 2023; 13:1035452. [PMID: 36685202 PMCID: PMC9846518 DOI: 10.3389/fphys.2022.1035452] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 12/13/2022] [Indexed: 01/06/2023] Open
Abstract
Background and aims: Sex differences in the rate and occurrence of cerebrovascular diseases (e.g., stroke) indicate a role for female sex hormones (i.e., oestrogen and progesterone) in cerebrovascular function and regulation. However, it remains unclear how cerebrovascular function differs between the sexes, and between distinct phases of the menstrual cycle. This study aimed to compare cerebrovascular-CO2 responsiveness in 1) females during the early follicular (EF), ovulatory (O) and mid-luteal (ML) phases of their menstrual cycle; and 2) males compared to females during phases of lower oestrogen (EF) and higher oestrogen (O). Methods: Eleven females (25 ± 5 years) complete experimental sessions in the EF (n = 11), O (n = 9) and ML (n = 11) phases of the menstrual cycle. Nine males (22 ± 3 years) completed two experimental sessions, approximately 2 weeks apart for comparison to females. Middle and posterior cerebral artery velocity (MCAv, PCAv) was measured at rest, during two stages of hypercapnia (2% and 5% CO2 inhalation) and hypocapnia (voluntary hyperventilation to an end-tidal CO2 of 30 and 24 mmHg). The linear slope of the cerebral blood velocity response to changes in end-tidal CO2 was calculated to measure cerebrovascular-CO2 responsiveness.. Results: In females, MCAv-CO2 responsiveness to hypocapnia was lower during EF (-.78 ± .45 cm/s/mmHg) when compared to the O phase (-1.17 ± .52 cm/s/mmHg; p < .05) and the ML phase (-1.30 ± .82; p < .05). MCAv-CO2 responsiveness to hypercapnia and hypo-to-hypercapnia, and PCAv-CO2 responsiveness across the CO2 range were similar between menstrual phases (p ≥ .20). MCAv-CO2 responsiveness to hypo-to hypercapnia was greater in females compared to males (3.12 ± .91 cm/s/mmHg vs. 2.31 ± .46 cm/s/mmHg; p = .03), irrespective of menstrual phase (EF or O). Conclusion: Females during O and ML phases have an enhanced vasoconstrictive capacity of the MCA compared to the EF phase. Additionally, biological sex differences can influence cerebrovascular-CO2 responsiveness, dependent on the insonated vessel.
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Affiliation(s)
- Bethany D. Skinner
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom,Centre for Human Brain Health, University of Birmingham, Edgbaston, Birmingham, United Kingdom,*Correspondence: Bethany D. Skinner,
| | - Samuel R. C. Weaver
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom,Centre for Human Brain Health, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Samuel J. E. Lucas
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom,Centre for Human Brain Health, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Rebekah A. I. Lucas
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
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Williams EL, Hockin BCD, Heeney ND, Elabd K, Chong H, Blaber AP, Robinovitch SN, Parsons IT, Claydon VE. Exaggerated postural sway improves orthostatic cardiovascular and cerebrovascular control. Front Cardiovasc Med 2023; 10:1040036. [PMID: 36873416 PMCID: PMC9978805 DOI: 10.3389/fcvm.2023.1040036] [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: 09/08/2022] [Accepted: 01/23/2023] [Indexed: 02/18/2023] Open
Abstract
Introduction Healthy individuals with poor cardiovascular control, but who do not experience syncope (fainting), adopt an innate strategy of increased leg movement in the form of postural sway that is thought to counter orthostatic (gravitational) stress on the cardiovascular system. However, the direct effect of sway on cardiovascular hemodynamics and cerebral perfusion is unknown. If sway produces meaningful cardiovascular responses, it could be exploited clinically to prevent an imminent faint. Methods Twenty healthy adults were instrumented with cardiovascular (finger plethysmography, echocardiography, electrocardiogram) and cerebrovascular (transcranial Doppler) monitoring. Following supine rest, participants performed a baseline stand (BL) on a force platform, followed by three trials of exaggerated sway (anterior-posterior, AP; mediolateral, ML; square, SQ) in a randomized order. Results All exaggerated postural sway conditions improved systolic arterial pressure (SAP, p = 0.001) responses, while blunting orthostatic reductions in stroke volume (SV, p < 0.01) and cerebral blood flow (CBFv, p < 0.05) compared to BL. Markers of sympathetic activation (power of low-frequency oscillations in SAP, p < 0.001) and maximum transvalvular flow velocity (p < 0.001) were reduced during exaggerated sway conditions. Responses were dose-dependent, with improvements in SAP (p < 0.001), SV (p < 0.001) and CBFv (p = 0.009) all positively correlated with total sway path length. Coherence between postural movements and SAP (p < 0.001), SV (p < 0.001) and CBFv (p = 0.003) also improved during exaggerated sway. Discussion Exaggerated sway improves cardiovascular and cerebrovascular control and may supplement cardiovascular reflex responses to orthostatic stress. This movement provides a simple means to boost orthostatic cardiovascular control for individuals with syncope, or those with occupations that require prolonged motionless standing.
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Affiliation(s)
- Erin L Williams
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Brooke C D Hockin
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Natalie D Heeney
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Karam Elabd
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Helen Chong
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Andrew P Blaber
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Stephen N Robinovitch
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Iain T Parsons
- Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, United Kingdom.,School of Cardiovascular Medicine and Sciences, King's College London, London, United Kingdom
| | - Victoria E Claydon
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
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Deseoe J, Schwarz A, Pipping T, Lehmann A, Veerbeek JM, Luft AR, Wegener S, Globas C, Held JPO. Cerebral blood flow velocity progressively decreases with increasing levels of verticalization in healthy adults. A cross-sectional study with an observational design. Front Neurol 2023; 14:1149673. [PMID: 37139076 PMCID: PMC10149656 DOI: 10.3389/fneur.2023.1149673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Accepted: 03/20/2023] [Indexed: 05/05/2023] Open
Abstract
Background Autoregulation of the cerebral vasculature keeps brain perfusion stable over a range of systemic mean arterial pressures to ensure brain functioning, e.g., in different body positions. Verticalization, i.e., transfer from lying (0°) to upright (70°), which causes systemic blood pressure drop, would otherwise dramatically lower cerebral perfusion pressure inducing fainting. Understanding cerebral autoregulation is therefore a prerequisite to safe mobilization of patients in therapy. Aim We measured the impact of verticalization on cerebral blood flow velocity (CBFV) and systemic blood pressure (BP), heart rate (HR) and oxygen saturation in healthy individuals. Methods We measured CBFV in the middle cerebral artery (MCA) of the dominant hemisphere in 20 subjects using continuous transcranial doppler ultrasound (TCD). Subjects were verticalized at 0°, -5°, 15°, 30°, 45° and 70° for 3-5 min each, using a standardized Sara Combilizer chair. In addition, blood pressure, heart rate and oxygen saturation were continuously monitored. Results We show that CBFV progressively decreases in the MCA with increasing degrees of verticalization. Systolic and diastolic BP, as well as HR, show a compensatory increase during verticalization. Conclusion In healthy adults CBFV changes rapidly with changing levels of verticalization. The changes in the circulatory parameters are similar to results regarding classic orthostasis. Registration ClinicalTrials.gov, identifier: NCT04573114.
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Affiliation(s)
- Julian Deseoe
- Department of Neurology, University Hospital Zurich and University of Zurich, Zurich, Switzerland
| | - Anne Schwarz
- Department of Neurology, University Hospital Zurich and University of Zurich, Zurich, Switzerland
| | - Theodor Pipping
- Department of Neurology, University Hospital Zurich and University of Zurich, Zurich, Switzerland
| | - Aurelia Lehmann
- Department of Neurology, University Hospital Zurich and University of Zurich, Zurich, Switzerland
| | - Janne M. Veerbeek
- Department of Neurology, University Hospital Zurich and University of Zurich, Zurich, Switzerland
- Neurocenter, Luzerner Kantonsspital, Lucerne, Switzerland
| | - Andreas R. Luft
- Department of Neurology, University Hospital Zurich and University of Zurich, Zurich, Switzerland
| | - Susanne Wegener
- Department of Neurology, University Hospital Zurich and University of Zurich, Zurich, Switzerland
| | - Christoph Globas
- Department of Neurology, University Hospital Zurich and University of Zurich, Zurich, Switzerland
- *Correspondence: Christoph Globas
| | - Jeremia P. O. Held
- Department of Neurology, University Hospital Zurich and University of Zurich, Zurich, Switzerland
- Rehabilitation Center Triemli Zurich, Valens Clinics, Zurich, Switzerland
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Validity of transcranial Doppler ultrasonography-determined dynamic cerebral autoregulation estimated using transfer function analysis. J Clin Monit Comput 2022; 36:1711-1721. [PMID: 35075510 DOI: 10.1007/s10877-022-00817-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 01/19/2022] [Indexed: 10/19/2022]
Abstract
Transcranial Doppler ultrasonography (TCD) is used widely to evaluate dynamic cerebral autoregulation (dCA). However, the validity of TCD-determined dCA remains unknown because TCD is only capable of measuring blood velocity and thus only provides an index as opposed to true blood flow. To test the validity of TCD-determined dCA, in nine healthy subjects, dCA was evaluated by transfer function analysis (TFA) using cerebral blood flow (CBF) or TCD-measured cerebral blood velocity during a perturbation that induces reductions in TCD-determined dCA, lower body negative pressure (LBNP) at two different stages: LBNP - 15 mmHg and - 50 mmHg. Internal carotid artery blood flow (ICA Q) was assessed as an index of CBF using duplex Doppler ultrasound. The TFA low frequency (LF) normalized gain (ngain) calculated using ICA Q increased during LBNP at - 50 mmHg (LBNP50) from rest (P = 0.005) and LBNP at - 15 mmHg (LBNP15) (P = 0.015), indicating an impaired dCA. These responses were the same as those obtained using TCD-measured cerebral blood velocity (from rest and LBNP15; P = 0.001 and P = 0.015). In addition, the ICA Q-determined TFA LF ngain from rest to LBNP50 was significantly correlated with TCD-determined TFA LF ngain (r = 0.460, P = 0.016) despite a low intraclass correlation coefficient. Moreover, in the Bland-Altman analysis, the difference in the TFA LF ngains determined by blood flow and velocity was within the margin of error, indicating that the two measurement methods can be interpreted as equivalent. These findings suggest that TCD-determined dCA can be representative of actual dCA evaluated with CBF.
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Aaron SE, Tomoto T, Zhang R, Thyfault JP, Vidoni ED, Montgomery RN, Burns JM, Billinger SA. Statin contribution to middle cerebral artery blood flow velocity in older adults at risk for dementia. Eur J Appl Physiol 2022; 122:2417-2426. [PMID: 35960268 PMCID: PMC9830632 DOI: 10.1007/s00421-022-05022-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 08/02/2022] [Indexed: 01/12/2023]
Abstract
PURPOSE It is plausible that statins could improve cerebral blood flow through pleiotropic mechanisms. The purpose of this investigation was to assess the contribution of statins to cerebrovascular variables in older adults with dyslipidemia and familial history of dementia. Furthermore, we explored the interaction between statin use and sex due to prevalent bias in statin trials. METHODS Middle cerebral artery blood flow velocity (MCAv) was measured using transcranial Doppler ultrasound. Continuous supine rest recordings lasted 8 min. Participants included in analyses were statin (n = 100) or non-statin users (n = 112). RESULTS MCAv and cerebrovascular conductance were significantly higher in statin users (p = 0.047; p = 0.04), and pulsatility index (PI) was significantly lower in statin users (p < 0.01). An interaction effect between statin use and sex was present for PI (p = 0.02); female statin users had significantly lower cerebrovascular resistance than the other three groups. CONCLUSION In this cross-sectional analysis, statin use was positively associated with cerebrovascular variables in older adults at risk for dementia. Female statin users had significantly higher resting MCAv and cerebrovascular conductance than female non-statin users. The greatest contribution of statin use was the association with reduced cerebrovascular resistance. Given that cerebrovascular dysregulation is one of the earliest changes in Alzheimer's disease and related dementia pathology, targeting the cerebrovasculature with statins may be a promising prevention strategy.
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Affiliation(s)
- Stacey E Aaron
- Department of Neurology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Tsubasa Tomoto
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX, USA
- Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and Technology, Ibaraki, Japan
| | - Rong Zhang
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX, USA
- Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and Technology, Ibaraki, Japan
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - John P Thyfault
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, USA
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Kansas Medical Center, Kansas City, KS, USA
- Research Service, Kansas City Veterans Affairs Medical Center, Kansas City, KS, USA
- Center for Children's Healthy Lifestyles and Nutrition, Kansas City, MO, USA
- University of Kansas Alzheimer's Research Disease Center, Fairway, KS, USA
| | - Eric D Vidoni
- Department of Neurology, University of Kansas Medical Center, Kansas City, KS, USA
- University of Kansas Alzheimer's Research Disease Center, Fairway, KS, USA
| | - Robert N Montgomery
- Department of Biostatistics and Data Science, University of Kansas Medical Center, Kansas City, KS, USA
| | - Jeffrey M Burns
- University of Kansas Alzheimer's Research Disease Center, Fairway, KS, USA
| | - Sandra A Billinger
- Department of Neurology, University of Kansas Medical Center, Kansas City, KS, USA.
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, USA.
- University of Kansas Alzheimer's Research Disease Center, Fairway, KS, USA.
- Department of Physical Medicine and Rehabilitation, University of Kansas Medical Center, Kansas City, KS, USA.
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Gerlach DA, Maier A, Manuel J, Bach A, Hoff A, Hönemann J, Heusser K, Voit D, Frahm J, Jordan J, Tank J. Real‐Time Magnetic Resonance Imaging to Study Orthostatic Intolerance Mechanisms in Human Beings: Proof of Concept. J Am Heart Assoc 2022; 11:e026437. [PMID: 36300662 PMCID: PMC9673621 DOI: 10.1161/jaha.122.026437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Background Discerning the mechanisms driving orthostatic symptoms in human beings remains challenging. Therefore, we developed a novel approach combining cardiac and cerebral real‐time magnetic resonance imaging, beat‐to‐beat physiological monitoring, and orthostatic stress testing through lower‐body negative pressure (LBNP). We conducted a proof‐of‐concept study in a patient with severe orthostatic hypotension. Methods and Results We included a 46‐year‐old man with pure autonomic failure. Without and during −30 mmHg LBNP, we obtained 3T real‐time magnetic resonance imaging of the cardiac short axis and quantitative flow measurements in the pulmonary trunk and middle cerebral artery. Blood pressure was 118/74 mmHg during supine rest and 58/35 mmHg with LBNP. With LBNP, left ventricular stroke volume decreased by 44.6%, absolute middle cerebral artery flow by 37.6%, and pulmonary trunk flow by 40%. Conclusions Combination of real‐time magnetic resonance imaging, LBNP, and continuous blood pressure monitoring provides a promising new approach to study orthostatic intolerance mechanisms in human beings.
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Affiliation(s)
- Darius A. Gerlach
- Institute of Aerospace Medicine German Aerospace Center (DLR) Cologne Germany
| | - Andrea Maier
- Department of Neurology University Hospital Aachen Aachen Germany
| | - Jorge Manuel
- Institute of Aerospace Medicine German Aerospace Center (DLR) Cologne Germany
- Institute for Neuroradiology Hannover Medical School Hannover Germany
| | - Anja Bach
- Institute of Aerospace Medicine German Aerospace Center (DLR) Cologne Germany
| | - Alex Hoff
- Institute of Aerospace Medicine German Aerospace Center (DLR) Cologne Germany
| | - Jan‐Niklas Hönemann
- Institute of Aerospace Medicine German Aerospace Center (DLR) Cologne Germany
- Department of Internal Medicine III, Division of Cardiology, Pneumology, Angiology, and Intensive Care University of Cologne Germany
| | - Karsten Heusser
- Institute of Aerospace Medicine German Aerospace Center (DLR) Cologne Germany
| | - Dirk Voit
- Biomedical NMR Max Planck Institute for Multidisciplinary Sciences Göttingen Germany
| | - Jens Frahm
- Biomedical NMR Max Planck Institute for Multidisciplinary Sciences Göttingen Germany
| | - Jens Jordan
- Institute of Aerospace Medicine German Aerospace Center (DLR) Cologne Germany
- Medical Faculty University of Cologne Germany
| | - Jens Tank
- Institute of Aerospace Medicine German Aerospace Center (DLR) Cologne Germany
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Williams EL, Khan FM, Claydon VE. Counter pressure maneuvers for syncope prevention: A semi-systematic review and meta-analysis. Front Cardiovasc Med 2022; 9:1016420. [PMID: 36312294 PMCID: PMC9606335 DOI: 10.3389/fcvm.2022.1016420] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 09/20/2022] [Indexed: 11/24/2022] Open
Abstract
Physical counter pressure maneuvers (CPM) are movements that are recommended to delay or prevent syncope (fainting) by recruiting the skeletal muscle pump to augment cardiovascular control. However, these recommendations are largely based on theoretical benefit, with limited data evaluating the efficacy of CPM to prevent syncope in the real-world setting. We conducted a semi-systematic literature review and meta-analysis to assess CPM efficacy, identify literature gaps, and highlight future research needs. Articles were identified through a literature search (PubMed, April 2022) of peer-reviewed publications evaluating the use of counter pressure or other lower body maneuvers to prevent syncope. Two team members independently screened records for inclusion and extracted data. From 476 unique records identified by the search, 45 met inclusion criteria. Articles considered various syncopal conditions (vasovagal = 12, orthostatic hypotension = 8, postural orthostatic tachycardia syndrome = 1, familial dysautonomia = 2, spinal cord injury = 1, blood donation = 10, healthy controls = 11). Maneuvers assessed included hand gripping, leg fidgeting, stepping, tiptoeing, marching, calf raises, postural sway, tensing (upper, lower, whole body), leg crossing, squatting, “crash” position, and bending foreword. CPM were assessed in laboratory-based studies (N = 28), the community setting (N = 4), both laboratory and community settings (N = 3), and during blood donation (N = 10). CPM improved standing systolic blood pressure (+ 14.8 ± 0.6 mmHg, p < 0.001) and heart rate (+ 1.4 ± 0.5 bpm, p = 0.006), however, responses of total peripheral resistance, stroke volume, or cerebral blood flow were not widely documented. Most patients experienced symptom improvement following CPM use (laboratory: 60 ± 4%, community: 72 ± 9%). The most prominent barrier to employing CPM in daily living was the inability to recognize an impending faint. Patterns of postural sway may also recruit the skeletal muscle pump to enhance cardiovascular control, and its potential as a discrete, proactive CPM needs further evaluation. Physical CPM were successful in improving syncopal symptoms and producing cardiovascular responses that may bolster against syncope; however, practical limitations may restrict applicability for use in daily living.
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Zhang K, Ren W, Li TX, Wang ZL, Gao BL, Xia JC, Gao HL, Wang YF, Gu JJ. Sub-satisfactory recanalization of severe middle cerebral artery stenoses can significantly improve hemodynamics. Front Cardiovasc Med 2022; 9:922616. [PMID: 36247480 PMCID: PMC9558820 DOI: 10.3389/fcvm.2022.922616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 09/07/2022] [Indexed: 11/13/2022] Open
Abstract
PurposeTo investigate the effect of sub-satisfactory stent recanalization on hemodynamic stresses for severe stenoses of the middle cerebral artery (MCA) M 1 segment.Materials and methodsPatients with severe stenoses of the MCA M1 segment treated with endovascular stent angioplasty were retrospectively enrolled. Three-dimensional digital subtraction angiography before and after stenting was performed; the computational fluid dynamics (CFD) analysis of hemodynamic stresses at the stenosis and normal segments proximal and distal to the stenoses was analyzed.ResultsFifty-one patients with severe stenosis at the MCA M1 segment were enrolled, with the stenosis length ranging from 5.1 to 12.8 mm (mean 9 ± 3.3 mm). Stent angioplasty was successful in all (100%) the patients. The angiography immediately after stenting demonstrated a significant (P < 0.05) decrease in MCA stenosis after comparison with before stenting (31.4 ±12.5% vs. 87.5 ± 9.6%), with residual stenosis of 15–30% (mean 22.4 ± 3.5%). Before stenting, the total pressure was significantly higher (P < 0.0001), while the WSS, velocity, and vorticity were all significantly decreased (P < 0.0001) at the normal arterial segment proximal to the stenosis, and the total pressure, WSS, velocity, and vorticity were all significantly decreased (P < 0.0001) at the normal arterial segment distal to the stenosis compared with those at the stenosis. After sub-satisfactory stenting recanalization, all the hemodynamic stresses proximal or distal to the stenosis and at the perforator root were improved compared with those before stenting and were similar to those after virtual stenosis removal.ConclusionSub-satisfactory recanalization of severe MCA stenoses can significantly improve the hemodynamic status for cerebral perfusion at the stenoses.
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Taylor JM, Chang M, Vaughan J, Horn PS, Zhang B, Leach JL, Vadivelu S, Abruzzo T. Cerebral Arterial Growth in Childhood. Pediatr Neurol 2022; 134:59-66. [PMID: 35839526 DOI: 10.1016/j.pediatrneurol.2022.06.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 05/22/2022] [Accepted: 06/19/2022] [Indexed: 10/17/2022]
Abstract
BACKGROUND Improved understanding of cerebral arterial growth in children may lead to advances in the diagnosis and treatment of pediatric cerebrovascular disease. We correlated cross-sectional diameters of major cerebral arterial structures with age, sex, head circumference, weight, and height in children without cerebrovascular disease. METHODS Children with normal brain magnetic resonance imaging (MRI) were retrospectively identified and stratified into 23 age cohorts from birth to age 18 years. Absence of vascular disease was verified by medical record review. Demographic and biometric data were obtained from medical records. Intracranial arterial diameter (IAD) was measured on T2-weighted fast spin echo brain MRI of vertebral, basilar, internal carotid artery, and circle of Willis arterial segments. RESULTS A total of 307 subjects are included in the analysis, including 5833 vessel segments (mean age 8.4 years, 53% female). Indications for imaging were headache (73%), seizure (26%) and concussion (1%). IAD rapidly increased during the first year of life (mean growth velocity 0.064 to 0.213 mm/month) and then plateaued or slightly decreased between age one and 18 years (mean growth velocity -0.002 to 0.003 mm/month). Multivariable analysis shows strongest correlation with head circumference as a predictor of IAD. Weaker correlations are associated with weight and age. Height and sex are not well correlated with IAD. CONCLUSIONS Intracranial arteries grow rapidly during the first year of life and then sharply plateau or slightly decrease in luminal diameter between infancy and early adulthood. IAD is more closely correlated with head circumference than age.
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Affiliation(s)
- J Michael Taylor
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; University of Cincinnati, College of Medicine, Cincinnati, Ohio.
| | - Michael Chang
- Division of Ophthalmology, West Virginia University, School of Medicine, Morgantown, West Virginia
| | - Jessica Vaughan
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Paul S Horn
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; University of Cincinnati, College of Medicine, Cincinnati, Ohio; Division of Biostatistics and Epidemiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Bin Zhang
- University of Cincinnati, College of Medicine, Cincinnati, Ohio; Division of Biostatistics and Epidemiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - James L Leach
- University of Cincinnati, College of Medicine, Cincinnati, Ohio; Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Sudhakar Vadivelu
- University of Cincinnati, College of Medicine, Cincinnati, Ohio; Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Division of Neurosurgery, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Todd Abruzzo
- Department of Radiology, Phoenix Children's Medical Group, Phoenix, Arizona; Mayo Clinic College of Medicine, Phoenix, Arizona; University of Arizona, College of Medicine, Phoenix, Arizona
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Cilhoroz BT, DeBlois JP, Lefferts WK, Keller AP, Pagan Lassalle P, Meyer ML, Stoner L, Heffernan KS. Exploration of cerebral hemodynamic pathways through which large artery function affects neurovascular coupling in young women. Front Cardiovasc Med 2022; 9:914439. [PMID: 36035945 PMCID: PMC9411931 DOI: 10.3389/fcvm.2022.914439] [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: 04/06/2022] [Accepted: 07/25/2022] [Indexed: 11/13/2022] Open
Abstract
BackgroundThe interactions between large artery function and neurovascular coupling (NVC) are emerging as important contributors to cognitive health. Women are disproportionally affected by Alzheimer's disease and related dementia later in life. Understanding large artery correlates of NVC in young women may help with preservation of cognitive health with advancing age.PurposeTo explore the association between large artery function, NVC and cognitive performance in young women.MethodsVascular measurements were made in 61 women (21 ± 4 yrs) at rest and during a cognitive challenge (Stroop task). Transcranial Doppler was used to measure left middle cerebral artery (MCA) maximum velocity (Vmax), mean velocity (Vmean), and pulsatility index (PI). NVC was determined as MCA blood velocity reactivity to the Stroop task. Large artery function was determined using carotid-femoral pulse wave velocity (cfPWV) as a proxy measure of aortic stiffness and carotid ultrasound-derived measures of compliance and reactivity (diameter change to the Stroop task). Cognitive function was assessed separately using a computerized neurocognitive battery that included appraisal of response speed, executive function, information processing efficiency, memory, attention/concentration, and impulsivity.ResultsMCA Vmax reactivity was positively associated with executive function (β = 0.26, 95% CI 0.01–0.10); MCA Vmean reactivity was negatively associated with response speed (β = −0.33, 95% CI −0.19 to −0.02) and positively with memory score (β = 0.28, 95% CI 0.01–0.19). MCA PI reactivity was negatively associated with attention performance (β = −0.29, 95% CI −14.9 to −1.0). Path analyses identified significant paths (p < 0.05) between carotid compliance and carotid diameter reactivity to select domains of cognitive function through MCA reactivity.ConclusionsNVC was associated with cognitive function in young women. Carotid artery function assessed as carotid compliance and carotid reactivity may contribute to optimal NVC in young women through increased blood flow delivery and reduced blood flow pulsatility.
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Affiliation(s)
- Burak T. Cilhoroz
- Department of Exercise Science, Syracuse University, Syracuse, NY, United States
| | - Jacob P. DeBlois
- Department of Exercise Science, Syracuse University, Syracuse, NY, United States
| | - Wesley K. Lefferts
- Department of Kinesiology, Iowa State University, Ames, IA, United States
| | - Allison P. Keller
- Department of Exercise Science, Syracuse University, Syracuse, NY, United States
| | - Patricia Pagan Lassalle
- Department of Exercise and Sport Science, University of North Carolina, Chapel Hill, NC, United States
| | - Michelle L. Meyer
- Department of Epidemiology, Gilling's School of Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- Department of Emergency Medicine, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Lee Stoner
- Department of Exercise and Sport Science, University of North Carolina, Chapel Hill, NC, United States
- Department of Epidemiology, Gilling's School of Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Kevin S. Heffernan
- Department of Exercise Science, Syracuse University, Syracuse, NY, United States
- *Correspondence: Kevin S. Heffernan
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Skow RJ, Brothers RM, Claassen JAHR, Day TA, Rickards CA, Smirl JD, Brassard P. On the use and misuse of cerebral hemodynamics terminology using Transcranial Doppler ultrasound: a call for standardization. Am J Physiol Heart Circ Physiol 2022; 323:H350-H357. [PMID: 35839156 DOI: 10.1152/ajpheart.00107.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cerebral hemodynamics (e.g., cerebral blood flow) can be measured and quantified using many different methods, with Transcranial Doppler ultrasound (TCD) being one of the most commonly utilized approaches. In human physiology, the terminology used to describe metrics of cerebral hemodynamics are inconsistent, and in some instances technically inaccurate; this is especially true when evaluating, reporting, and interpreting measures from TCD. Therefore, this perspectives article presents recommended terminology when reporting cerebral hemodynamic data. We discuss the current use and misuse of the terminology in the context of using TCD to measure and quantify cerebral hemodynamics and present our rationale and consensus on the terminology that we recommend moving forward. For example, one recommendation is to discontinue use of the term "cerebral blood flow velocity" in favor of "cerebral blood velocity" with precise indication of the vessel of interest. We also recommend clarity when differentiating between discrete cerebrovascular regulatory mechanisms, namely cerebral autoregulation, neurovascular coupling, and cerebrovascular reactivity. This will be a useful guide for investigators in the field of cerebral hemodynamics research.
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Affiliation(s)
- Rachel J Skow
- Department of Kinesiology, The University of Texas at Arlington, Arlington, TX, United States
| | - R Matthew Brothers
- Department of Kinesiology, The University of Texas at Arlington, Arlington, TX, United States
| | - Jurgen A H R Claassen
- Department of Geriatrics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Trevor A Day
- Department of Biology, Faculty of Science and Technology, Mount Royal University, Calgary, Alberta, Canada
| | - Caroline A Rickards
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - Jonathan D Smirl
- Sport Injury Prevention Research Centre, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,Cerebrovascular Concussion Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada.,Integrated Concussion Research Program, University of Calgary, Calgary, Alberta, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada.,Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Patrice Brassard
- Department of Kinesiology, Faculty of Medicine, Université Laval, Québec, Canada.,Research center of the Institut universitaire de cardiologie et de pneumologie de Québec, Canada
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Abbariki F, Roy M, Labrecque L, Drapeau A, Imhoff S, Smirl JD, Brassard P. Influence of high-intensity interval training to exhaustion on the directional sensitivity of the cerebral pressure-flow relationship in young endurance-trained men. Physiol Rep 2022; 10:e15384. [PMID: 35822439 PMCID: PMC9277516 DOI: 10.14814/phy2.15384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 06/23/2022] [Indexed: 06/15/2023] Open
Abstract
We previously reported subtle dynamic cerebral autoregulation (dCA) alterations following 6 weeks of high-intensity interval training (HIIT) to exhaustion using transfer function analysis (TFA) on forced mean arterial pressure (MAP) oscillations in young endurance-trained men. However, accumulating evidence suggests the cerebrovasculature better buffers cerebral blood flow changes when MAP acutely increases compared to when MAP acutely decreases. Whether HIIT affects the directional sensitivity of the cerebral pressure-flow relationship in these athletes is unknown. In 18 endurance-trained men (age: 27 ± 6 years, VO2 max: 55.5 ± 4.7 ml·kg-1 ·min-1 ), we evaluated the impact of 6 weeks of HIIT to exhaustion on dCA directionality using induced MAP oscillations during 5-min 0.05 and 0.10 Hz repeated squat-stands. We calculated time-adjusted changes in middle cerebral artery mean blood velocity (MCAv) per change in MAP (ΔMCAvT /ΔMAPT ) for each squat transition. Then, we compared averaged ΔMCAvT /ΔMAPT during MAP increases and decreases. Before HIIT, ΔMCAvT /ΔMAPT was comparable between MAP increases and decreases during 0.05 Hz repeated squat-stands (p = 0.518). During 0.10 Hz repeated squat-stands, ΔMCAvT /ΔMAPT was lower during MAP increases versus decreases (0.87 ± 0.17 vs. 0.99 ± 0.23 cm·s-1 ·mmHg-1 , p = 0.030). Following HIIT, ΔMCAvT /ΔMAPT was superior during MAP increases over decreases during 0.05 Hz repeated squat-stands (0.97 ± 0.38 vs. 0.77 ± 0.35 cm·s-1 ·mmHg-1 , p = 0.002). During 0.10 Hz repeated squat-stands, dCA directional sensitivity disappeared (p = 0.359). These results suggest the potential for HIIT to influence the directional sensitivity of the cerebral pressure-flow relationship in young endurance-trained men.
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Affiliation(s)
- Faezeh Abbariki
- Department of Kinesiology, Faculty of MedicineUniversité LavalQuébec CityQuébecCanada
- Research Center of the Institut Universitaire de Cardiologie et de Pneumologie de QuébecQuébec CityQuébecCanada
| | - Marc‐Antoine Roy
- Department of Kinesiology, Faculty of MedicineUniversité LavalQuébec CityQuébecCanada
- Research Center of the Institut Universitaire de Cardiologie et de Pneumologie de QuébecQuébec CityQuébecCanada
| | - Lawrence Labrecque
- Department of Kinesiology, Faculty of MedicineUniversité LavalQuébec CityQuébecCanada
- Research Center of the Institut Universitaire de Cardiologie et de Pneumologie de QuébecQuébec CityQuébecCanada
| | - Audrey Drapeau
- Department of Kinesiology, Faculty of MedicineUniversité LavalQuébec CityQuébecCanada
- Research Center of the Institut Universitaire de Cardiologie et de Pneumologie de QuébecQuébec CityQuébecCanada
| | - Sarah Imhoff
- Department of Kinesiology, Faculty of MedicineUniversité LavalQuébec CityQuébecCanada
- Research Center of the Institut Universitaire de Cardiologie et de Pneumologie de QuébecQuébec CityQuébecCanada
| | - Jonathan D. Smirl
- Cerebrovascular Concussion Laboratory, Faculty of KinesiologyUniversity of CalgaryCalgaryAlbertaCanada
- Sport Injury Prevention Research Centre, Faculty of KinesiologyUniversity of CalgaryCalgaryAlbertaCanada
- Human Performance Laboratory, Faculty of KinesiologyUniversity of CalgaryCalgaryAlbertaCanada
- Hotchkiss Brain InstituteUniversity of CalgaryCalgaryAlbertaCanada
- Integrated Concussion Research ProgramUniversity of CalgaryCalgaryAlbertaCanada
- Alberta Children's Hospital Research InstituteUniversity of CalgaryCalgaryAlbertaCanada
- Libin Cardiovascular Institute of AlbertaUniversity of CalgaryAlbertaCanada
- Concussion Research Laboratory, Faculty of Health and Exercise ScienceUniversity of British ColumbiaKelownaBritish ColumbiaCanada
| | - Patrice Brassard
- Department of Kinesiology, Faculty of MedicineUniversité LavalQuébec CityQuébecCanada
- Research Center of the Institut Universitaire de Cardiologie et de Pneumologie de QuébecQuébec CityQuébecCanada
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Kawasaki A, Hayashi N. Playing a musical instrument increases blood flow in the middle cerebral artery. PLoS One 2022; 17:e0269679. [PMID: 35675278 PMCID: PMC9176837 DOI: 10.1371/journal.pone.0269679] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Accepted: 05/25/2022] [Indexed: 11/18/2022] Open
Abstract
Purpose Studies using functional magnetic resonance imaging and positron-emission tomography suggest that many regions of the brain are activated by such complex muscle activity. Although these studies demonstrated relative increases in blood flow in some brain regions with increased neural activity, whether or not the absolute value of cerebral blood flow increases has yet to be elucidated. It also remains unknown whether playing musical instruments affects cerebral blood flow. The aim of this study was to determine the impact of playing a musical instrument on blood flow velocity in the middle cerebral artery (MCAv) by using Doppler ultrasound to measure absolute values of arterial flow velocity. Methods Thirteen musicians performed three pieces of music with different levels of difficulty: play for the first time (FS), music in practice (PR) and already mastered (MS) on either piano or violin. MCAv was recorded continuously from 10 min before until 10 min after playing. Associations between the cerebral blood flow response and blood pressure and gas-exchange variables were examined. Results PR and MS significantly increased the MCAv. The blood pressure increased significantly in performances of all difficulty levels except for MS. There were no significant changes in exhaled gas variables during the performance. Conclusion These findings suggest that playing a musical instrument increases MCAv, and that this change is influenced by the difficulty of the performance.
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Affiliation(s)
- Ai Kawasaki
- Department of Social and Human Sciences, Tokyo Institute of Technology, Tokyo, Japan
| | - Naoyuki Hayashi
- Department of Social and Human Sciences, Tokyo Institute of Technology, Tokyo, Japan.,Faculty of Sport Sciences, Waseda University, Saitama, Japan
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Bliss ES, Wong RHX, Howe PRC, Mills DE. The Effects of Aerobic Exercise Training on Cerebrovascular and Cognitive Function in Sedentary, Obese, Older Adults. Front Aging Neurosci 2022; 14:892343. [PMID: 35663579 PMCID: PMC9158462 DOI: 10.3389/fnagi.2022.892343] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 04/11/2022] [Indexed: 11/15/2022] Open
Abstract
Cerebrovascular function and cognition decline with age and are further exacerbated by obesity and physical inactivity. This decline may be offset by aerobic exercise training (AT). We investigated the effects of 16 weeks AT on cerebrovascular and cognitive function in sedentary, obese, older adults. Twenty-eight participants were randomly allocated to AT or a control group. Before and after the intervention, transcranial Doppler ultrasonography was used to measure the cerebrovascular responsiveness (CVR) to physiological (hypercapnia, 5% carbon dioxide) and cognitive stimuli. AT increased the CVR to hypercapnia (98.5 ± 38.4% vs. 58.0 ± 42.0%, P = 0.021), CVR to cognitive stimuli (25.9 ± 6.1% vs. 16.4 ± 5.4%, P < 0.001) and total composite cognitive score (111 ± 14 vs. 104 ± 14, P = 0.004) compared with the control group. A very strong relationship was observed between the number of exercise sessions completed and CVR to cognitive stimuli (r = 0.878, P < 0.001), but not for CVR to hypercapnia (r = 0.246, P = 0.397) or total composite cognitive score (r = 0.213, P = 0.465). Cerebrovascular function and cognition improved following 16 weeks of AT and a dose-response relationship exists between the amount of exercise sessions performed and CVR to cognitive stimuli.
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Affiliation(s)
- Edward S. Bliss
- Respiratory and Exercise Physiology Research Group, School of Health and Medical Sciences, University of Southern Queensland, Ipswich, QLD, Australia
- *Correspondence: Edward S. Bliss,
| | - Rachel H. X. Wong
- Centre for Health Research, Institute for Resilient Regions, University of Southern Queensland, Ipswich, QLD, Australia
- Clinical Nutrition Research Centre, School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW, Australia
| | - Peter R. C. Howe
- Centre for Health Research, Institute for Resilient Regions, University of Southern Queensland, Ipswich, QLD, Australia
- Clinical Nutrition Research Centre, School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW, Australia
- Allied Health and Human Performance, University of South Australia, Adelaide, SA, Australia
| | - Dean E. Mills
- Respiratory and Exercise Physiology Research Group, School of Health and Medical Sciences, University of Southern Queensland, Ipswich, QLD, Australia
- Centre for Health Research, Institute for Resilient Regions, University of Southern Queensland, Ipswich, QLD, Australia
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41
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Maxwell JD, Bannell DJ, Brislane A, Carter SE, Miller GD, Roberts KA, Hopkins ND, Low DA, Carter HH, Thompson A, Claassen JAHR, Thijssen DHJ, Jones H. The impact of age, sex, cardio-respiratory fitness, and cardiovascular disease risk on dynamic cerebral autoregulation and baroreflex sensitivity. Eur J Appl Physiol 2022; 122:1531-1541. [PMID: 35429292 PMCID: PMC9132800 DOI: 10.1007/s00421-022-04933-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Accepted: 03/08/2022] [Indexed: 11/10/2022]
Abstract
Background Humans display an age-related decline in cerebral blood flow and increase in blood pressure (BP), but changes in the underlying control mechanisms across the lifespan are less well understood. We aimed to; (1) examine the impact of age, sex, cardiovascular disease (CVD) risk, and cardio-respiratory fitness on dynamic cerebral autoregulation and cardiac baroreflex sensitivity, and (2) explore the relationships between dynamic cerebral autoregulation (dCA) and cardiac baroreflex sensitivity (cBRS). Methods 206 participants aged 18–70 years were stratified into age categories. Cerebral blood flow velocity was measured using transcranial Doppler ultrasound. Repeated squat-stand manoeuvres were performed (0.10 Hz), and transfer function analysis was used to assess dCA and cBRS. Multivariable linear regression was used to examine the influence of age, sex, CVD risk, and cardio-respiratory fitness on dCA and cBRS. Linear models determined the relationship between dCA and cBRS. Results Age, sex, CVD risk, and cardio-respiratory fitness did not impact dCA normalised gain, phase, or coherence with minimal change in all models (P > 0.05). cBRS gain was attenuated with age when adjusted for sex and CVD risk (young–older; β = − 2.86 P < 0.001) along with cBRS phase (young–older; β = − 0.44, P < 0.001). There was no correlation between dCA normalised gain and phase with either parameter of cBRS. Conclusion Ageing was associated with a decreased cBRS, but dCA appears to remain unchanged. Additionally, our data suggest that sex, CVD risk, and cardio-respiratory fitness have little effect.
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Kurazumi T, Ogawa Y, Takko C, Kato T, Konishi T, Iwasaki KI. Short-Term Volume Loading Effects on Estimated Intracranial Pressure in Human Volunteers. Aerosp Med Hum Perform 2022; 93:347-353. [PMID: 35354513 DOI: 10.3357/amhp.6004.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
BACKGROUND: Short-term fluid loading is used as part of post-spaceflight medical procedures and clinical treatment in hospitals. Hypervolemia with hemodilution induced by rapid fluid infusion reportedly impaired dynamic cerebral autoregulation. However, the effects on intracranial pressure (ICP) remain unknown. Therefore, we estimated ICP noninvasively (nICP) to examine whether rapid fluid infusion would raise ICP.METHODS: Twelve healthy male volunteers underwent two discrete normal saline (NS) infusions (15 and 30 ml · kg-1 stages, NS-15 and NS-30, respectively) at a rate of 100 ml · min-1. The cerebral blood flow (CBF) velocity (CBFv) waveform from the middle cerebral artery obtained by transcranial Doppler ultrasonography was recorded, as was the arterial blood pressure (ABP) waveform at the radial artery obtained by tonometry. We then used these waveforms to calculate nICP, cerebral artery compliance, and the pulsatility index (PI) in an intracranial hydraulic model.RESULTS: nICP increased significantly in both infusion stages from preinfusion (preinfusion: 7.6 ± 3.4 mmHg; NS-15: 10.9 ± 3.3 mmHg; NS-30: 11.7 ± 4.2 mmHg). No significant changes were observed in cerebral artery compliance or PI. Although ABP did not change in any stage, CBFv increased significantly (preinfusion: 67 ± 10 cm · s-1; NS-15: 72 ± 12 cm · s-1; NS-30: 73 ± 12 cm · s-1).DISCUSSION: Hypervolemia with hemodilution induced by rapid fluid infusion caused increases in nICP and CBFv. No changes were observed in cerebral artery compliance or PI related to cerebrovascular impedance. These findings suggest that rapid fluid infusion may raise ICP with increased CBF.Kurazumi T, Ogawa Y, Takko C, Kato T, Konishi T, Iwasaki K. Short-term volume loading effects on estimated intracranial pressure in human volunteers. Aerosp Med Hum Perform. 2022; 93(4):347-353.
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43
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Intharakham K, Panerai RB, Robinson TG. The scalability of common paradigms for assessment of cognitive function: A functional transcranial Doppler study. PLoS One 2022; 17:e0266048. [PMID: 35344567 PMCID: PMC8959162 DOI: 10.1371/journal.pone.0266048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 03/12/2022] [Indexed: 11/18/2022] Open
Abstract
Cognitive paradigms induce changes in cerebral blood flow (CBF) associated with increased metabolic demand, namely neurovascular coupling (NVC). We tested the hypothesis that the effect of complexity and duration of cognitive paradigms will either enhance or inhibit the NVC response. Bilateral CBF velocity (CBFV) in the middle cerebral arteries (MCAs) via transcranial Doppler ultrasound (TCD), blood pressure (BP), electrocardiogram (ECG) and end-tidal CO2 (EtCO2) of 16 healthy participants (aged 21–71 years) were simultaneously recorded at rest and during randomized paradigms of different complexities (naming words beginning with P-,R-,V- words and serial subtractions of 100–2,100–7,1000–17), and durations (5s, 30s and 60s). CBFV responses were population mean normalized from a 30-s baseline period prior to task initiation. A significant increase in bilateral CBFV response was observed at the start of all paradigms and provided a similar pattern in most responses, irrespective of complexity or duration. Although significant inter-hemispherical differences were found during performance of R-word and all serial subtraction paradigms, no lateralisation was observed in more complex naming word tasks. Also, the effect of duration was manifested at late stages of 100–7, but not for other paradigms. CBFV responses could not distinguish different levels of complexity or duration with a single presentation of the cognitive paradigm. Further studies of the ordinal scalability of the NVC response are needed with more advanced modelling techniques, or different types of neural stimulation.
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Affiliation(s)
- Kannakorn Intharakham
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- * E-mail:
| | - Ronney B. Panerai
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, United Kingdom
| | - Thompson G. Robinson
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, United Kingdom
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44
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Secondary Analysis of Walking Activities During the Acute Stroke Hospital Stay and Cerebrovascular Health. Cardiopulm Phys Ther J 2022; 33:130-137. [DOI: 10.1097/cpt.0000000000000196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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45
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Fan JL, Nogueira RC, Brassard P, Rickards CA, Page M, Nasr N, Tzeng YC. Integrative physiological assessment of cerebral hemodynamics and metabolism in acute ischemic stroke. J Cereb Blood Flow Metab 2022; 42:454-470. [PMID: 34304623 PMCID: PMC8985442 DOI: 10.1177/0271678x211033732] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Restoring perfusion to ischemic tissue is the primary goal of acute ischemic stroke care, yet only a small portion of patients receive reperfusion treatment. Since blood pressure (BP) is an important determinant of cerebral perfusion, effective BP management could facilitate reperfusion. But how BP should be managed in very early phase of ischemic stroke remains a contentious issue, due to the lack of clear evidence. Given the complex relationship between BP and cerebral blood flow (CBF)-termed cerebral autoregulation (CA)-bedside monitoring of cerebral perfusion and oxygenation could help guide BP management, thereby improve stroke patient outcome. The aim of INFOMATAS is to 'identify novel therapeutic targets for treatment and management in acute ischemic stroke'. In this review, we identify novel physiological parameters which could be used to guide BP management in acute stroke, and explore methodologies for monitoring them at the bedside. We outline the challenges in translating these potential prognostic markers into clinical use.
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Affiliation(s)
- Jui-Lin Fan
- Manaaki Mānawa - The Centre for Heart Research, Department of Physiology, Faculty of Medical & Health Sciences, University of Auckland, Auckland, New Zealand
| | - Ricardo C Nogueira
- Neurology Department, School of Medicine, Hospital das Clinicas, University of São Paulo, São Paulo, Brazil.,Neurology Department, Hospital Nove de Julho, São Paulo, Brazil
| | - Patrice Brassard
- Department of Kinesiology, Faculty of Medicine, Université Laval, Québec, Canada.,Research Center of the Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Canada
| | - Caroline A Rickards
- Department of Physiology & Anatomy, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Matthew Page
- Department of Radiology, Wellington Regional Hospital, Wellington, New Zealand
| | - Nathalie Nasr
- Department of Neurology, Toulouse University Hospital, NSERM UMR 1297, Toulouse, France
| | - Yu-Chieh Tzeng
- Wellington Medical Technology Group, Department of Surgery & Anaesthesia, University of Otago, Wellington, New Zealand.,Centre for Translational Physiology, Department of Surgery & Anaesthesia, University of Otago, Wellington, New Zealand
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Washio T, Watanabe H, Suzuki K, Saito S, Ogoh S. Site-specific different dynamic cerebral autoregulation and cerebrovascular response to carbon dioxide in posterior cerebral circulation during isometric exercise in healthy young men. Auton Neurosci 2022; 238:102943. [PMID: 35086019 DOI: 10.1016/j.autneu.2022.102943] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 11/16/2021] [Accepted: 01/16/2022] [Indexed: 11/23/2022]
Abstract
Different cerebral blood flow (CBF) responses to exercise between the posterior cerebral artery (PCA) and vertebral artery (VA) have been previously observed, though the physiological mechanisms remain unknown. There is regional heterogeneity in sympathetic innervation between the PCA and VA, which may affect CBF regulation, especially during sympathoexcitation. Thus, in the present study, we hypothesized that different CBF regulatory mechanisms between PCA and VA contribute to heterogeneous CBF responses to isometric exercise. To test this hypothesis, in thirteen healthy young men, dynamic cerebral autoregulation (CA) and cerebrovascular CO2 reactivity (CVR), were identified in each artery during a 2-min isometric handgrip (IHG) exercise at 30% of maximum voluntary contraction. Similar to previous data, PCA cerebrovascular conductance (CVC) index was decreased from rest (P < 0.004), but not VA CVC during IHG exercise (P > 0.084). Dynamic CA in both PCA and VA were unaltered during the IHG exercise (P = 0.129). On the other hand, PCA CVR was increased during the IHG exercise (P < 0.001) while VA CVR was unchanged (P = 0.294). In addition, individual exercise-induced changes in end-tidal partial pressure of CO2 was related to the individual change in PCA blood velocity (P < 0.046), but was not observed for VA blood flow (P > 0.420). Therefore, these exercise-induced differences in CVR between PCA and VA may contribute to exercise-induced heterogeneous CBF response in the posterior cerebral circulation. These findings indicate that the site-specific posterior CBF should be considered in further research for assessing posterior cerebral circulation.
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Affiliation(s)
- Takuro Washio
- Department of Biomedical Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan
| | - Hironori Watanabe
- Department of Biomedical Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan
| | - Kazuya Suzuki
- Department of Biomedical Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan
| | - Shotaro Saito
- Department of Biomedical Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan
| | - Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan; Neurovascular Research Laboratory, University of South Wales, UK.
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Rastogi R, Morgan BJ, Badr MS, Chowdhuri S. Hypercapnia-induced vasodilation in the cerebral circulation is reduced in older adults with sleep-disordered breathing. J Appl Physiol (1985) 2022; 132:14-23. [PMID: 34709067 PMCID: PMC8721948 DOI: 10.1152/japplphysiol.00347.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The prevalence of sleep-disordered breathing (SDB) is higher in older adults compared with younger individuals. The increased propensity for ventilatory control instability in older adults may contribute to the increased prevalence of central apneas. Reductions in the cerebral vascular response to CO2 may exacerbate ventilatory overshoots and undershoots during sleep. Thus, we hypothesized that hypercapnia-induced cerebral vasodilation (HCVD) will be reduced in older compared with younger adults. In 11 older and 10 younger adults with SDB, blood flow velocity in the middle cerebral artery (MCAV) was measured using Doppler transcranial ultrasonography during multiple steady-state hyperoxic hypercapnic breathing trials while awake, interspersed with room air breathing. Changes in ventilation, MCAV, and mean arterial pressure (MAP) via finger plethysmography during the trials were compared with baseline eupneic values. For each hyperoxic hypercapnic trial, the change (Δ) in MCAV for a corresponding change in end-tidal CO2 and the HCVD or the change in cerebral vascular conductance (MCAV divided by MAP) for a corresponding change in end-tidal CO2 was determined. The hypercapnic ventilatory response was similar between the age groups, as was ΔMCAV/Δ[Formula: see text]. However, compared with young, older adults had a significantly smaller HCVD (1.3 ± 0.7 vs. 2.1 ± 0.6 units/mmHg, P = 0.004). Multivariable analyses demonstrated that age and nadir oxygen saturation during nocturnal polysomnography were significant predictors of HCVD. Thus, our data indicate that older age and SDB-related hypoxia are associated with diminished HCVD. We hypothesize that this impairment in vascular function may contribute to breathing instability during sleep in these individuals.NEW & NOTEWORTHY This study demonstrates, for the first time, in individuals with sleep-disordered breathing (SDB) that aging is associated with decreased hypercapnia-induced cerebral vasodilation (HCVD). In addition to advanced age, the magnitude of nocturnal oxygen desaturation due to SDB is an equal independent predictor of HCVD.
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Affiliation(s)
- R. Rastogi
- 1Medical Service, Sleep Medicine Section, John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan,2Division of Pulmonary/Critical Care and Sleep Medicine, Department of Medicine, Wayne State University School of Medicine, Detroit, Michigan
| | - B. J. Morgan
- 3Department of Orthopedics and Rehabilitation, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - M. S. Badr
- 1Medical Service, Sleep Medicine Section, John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan,2Division of Pulmonary/Critical Care and Sleep Medicine, Department of Medicine, Wayne State University School of Medicine, Detroit, Michigan
| | - S. Chowdhuri
- 1Medical Service, Sleep Medicine Section, John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan,2Division of Pulmonary/Critical Care and Sleep Medicine, Department of Medicine, Wayne State University School of Medicine, Detroit, Michigan
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Koktzoglou I, Huang R, Edelman RR. Quantitative time-of-flight MR angiography for simultaneous luminal and hemodynamic evaluation of the intracranial arteries. Magn Reson Med 2022; 87:150-162. [PMID: 34374455 PMCID: PMC8616782 DOI: 10.1002/mrm.28969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 07/19/2021] [Accepted: 07/25/2021] [Indexed: 01/03/2023]
Abstract
PURPOSE To report a quantitative time-of-flight (qTOF) MRA technique for simultaneous luminal and hemodynamic evaluation of the intracranial arteries. METHODS Implemented using a thin overlapping slab 3D stack-of-stars based 3-echo FLASH readout, qTOF was tested in a flow phantom and for imaging the intracranial arteries of 10 human subjects at 3 Tesla. Display of the intracranial arteries with qTOF was compared to resolution-matched and scan time-matched standard Cartesian 3D time-of-flight (TOF) MRA, whereas quantification of mean blood flow velocity with qTOF, done using a computer vision-based inter-echo image analysis procedure, was compared to 3D phase contrast MRA. Arterial-to-background contrast-to-noise ratio was measured, and intraclass correlation coefficient was used to evaluate agreement of flow velocities. RESULTS For resolution-matched protocols of similar scan time, qTOF portrayed the intracranial arteries with good morphological correlation with standard Cartesian TOF, and both techniques provided superior contrast-to-noise ratio and arterial delineation compared to phase contrast (20.6 ± 3.0 and 37.8 ± 8.7 vs. 11.5 ± 2.2, P < .001, both comparisons). With respect to phase contrast, qTOF showed excellent agreement for measuring mean flow velocity in the flow phantom (intraclass correlation coefficient = 0.981, P < .001) and good agreement in the intracranial arteries (intraclass correlation coefficient = 0.700, P < .001). Stack-of-stars data sampling used with qTOF eliminated oblique in-plane flow misregistration artifacts that were seen with standard Cartesian TOF. CONCLUSION qTOF is a new 3D MRA technique for simultaneous luminal and hemodynamic evaluation of the intracranial arteries that provides significantly greater contrast-to-noise ratio efficiency than phase contrast and eliminates misregistration artifacts from oblique in-plane blood flow that occur with standard 3D TOF.
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Affiliation(s)
- Ioannis Koktzoglou
- Department of Radiology, NorthShore University HealthSystem, Evanston, IL,Pritzker School of Medicine, University of Chicago, Chicago, IL
| | - Rong Huang
- Department of Radiology, NorthShore University HealthSystem, Evanston, IL
| | - Robert R. Edelman
- Department of Radiology, NorthShore University HealthSystem, Evanston, IL,Northwestern University Feinberg School of Medicine, Chicago, IL
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Novak P, Mukerji SS, Alabsi HS, Systrom D, Marciano SP, Felsenstein D, Mullally WJ, Pilgrim DM. Multisystem Involvement in Post-acute Sequelae of COVID-19 (PASC). Ann Neurol 2021; 91:367-379. [PMID: 34952975 PMCID: PMC9011495 DOI: 10.1002/ana.26286] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 12/15/2021] [Accepted: 12/20/2021] [Indexed: 11/11/2022]
Abstract
OBJECTIVE To describe cerebrovascular, neuropathic and autonomic features of post-acute sequelae of COVID-19 (PASC). METHODS This retrospective study evaluated consecutive patients with chronic fatigue, brain fog and orthostatic intolerance consistent with PASC. Controls included postural tachycardia syndrome patients (POTS) and healthy participants. Analyzed data included surveys and autonomic (Valsalva maneuver, deep breathing, sudomotor and tilt tests), cerebrovascular (cerebral blood flow velocity (CBFv) monitoring in middle cerebral artery), respiratory (capnography monitoring) and neuropathic (skin biopsies for assessment of small fiber neuropathy) testing and inflammatory/autoimmune markers. RESULTS Nine PASC patients were evaluated 0.7±0.3 years after a mild COVID-19 infection, treated as home observations. Autonomic, pain, brain fog, fatigue and dyspnea surveys were abnormal in PASC and POTS (n=10), compared to controls (n=15). Tilt table test reproduced the majority of PASC symptoms. Orthostatic CBFv declined in PASC (-20.0±13.4%) and POTS (-20.3±15.1%), compared to controls (-3.0±7.5%,p=0.001) and was independent of end-tidal carbon dioxide in PASC, but caused by hyperventilation in POTS. Reduced orthostatic CBFv in PASC included both subjects without (n=6) and with (n=3) orthostatic tachycardia. Dysautonomia was frequent (100% in both PASC and POTS) but was milder in PASC (p=0.013). PASC and POTS cohorts diverged in frequency of small fiber neuropathy (89% vs. 60%) but not in inflammatory markers (67% vs. 70%). Supine and orthostatic hypocapnia was observed in PASC. INTERPRETATION PASC following mild COVID-19 infection is associated with multisystem involvement including: 1) cerebrovascular dysregulation with persistent cerebral arteriolar vasoconstriction; 2) small fiber neuropathy and related dysautonomia; 3) respiratory dysregulation; 4) chronic inflammation. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Peter Novak
- Department of Neurology, Brigham and Women's Hospital, Boston, MA.,Harvard Medical School, Boston, MA
| | - Shibani S Mukerji
- Department of Neurology, Massachusetts General Hospital, Boston, MA.,Harvard Medical School, Boston, MA
| | - Haitham S Alabsi
- Department of Neurology, Massachusetts General Hospital, Boston, MA.,Harvard Medical School, Boston, MA
| | - David Systrom
- Department of Medicine, Pulmonary and Critical Care, Brigham and Women's Hospital, Boston, MA.,Harvard Medical School, Boston, MA
| | - Sadie P Marciano
- Department of Neurology, Brigham and Women's Hospital, Boston, MA
| | - Donna Felsenstein
- Department of Infectious Disease and Medicine, Massachusetts General Hospital, Boston, MA.,Harvard Medical School, Boston, MA
| | - William J Mullally
- Department of Neurology, Brigham and Women's Hospital, Boston, MA.,Harvard Medical School, Boston, MA
| | - David M Pilgrim
- Department of Neurology, Brigham and Women's Hospital, Boston, MA.,Harvard Medical School, Boston, MA
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Abdelhaleem NF, Mohamed YE. Effect of sphenopalatine ganglion block on intracranial pressure and cerebral venous outflow oxygenation during craniotomy for supratentorial brain tumours. Anaesth Crit Care Pain Med 2021; 41:101013. [PMID: 34954221 DOI: 10.1016/j.accpm.2021.101013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 10/06/2021] [Accepted: 11/20/2021] [Indexed: 11/29/2022]
Abstract
BACKGROUND Intraoperative intracranial pressure (ICP) control continues to be a challenge for anaesthetists during craniotomies. Although many standard brain-dehydrating protocols are available, they may be ineffective in certain surgical situations and may result in harm either to the systemic or cerebral circulation. Sphenopalatine ganglion block (SPGB) can reverse the vasodilatory effects of anaesthesia during craniotomy. METHODS This prospective randomised study was carried from June 2020 to February 2021. Fifty-two patients were randomly allocated into two groups, the block group (B) and the non-block control group (Non). Twenty-six patients were enrolled in the (B) group and received a bilateral transnasal SPG block with 2% lidocaine using a hallow culture swab prior to anaesthesia induction. Intraoperative monitoring was performed using standard American Society of Anesthesiologists (ASA) monitors in addition to invasive monitoring using intra-arterial cannulas and jugular venous bulb catheters. Subdural ICP monitors were also employed. The arterio-jugular oxygen difference in mmol/l (AjvDO2) was then calculated. Mean flow velocity cm/s (MFV) and pulsatility index (PI) were monitored in both groups using Transcranial Doppler. Haemodynamic data were recorded every 30 min from induction of anaesthesia until the closure of the dura. RESULTS There was a significant difference in ICP prior to the dural opening between the block group (B), mean ± sd 7.58 ± 1.47, and the non-block group (Non), mean ± sd (11.69 ± 1.72), p-value < 0.001. There was no significant difference in MFV between (B) group, mean ± sd 72.65 ± 2.28 and (Non) group, mean ± sd 71.19 ± 3.09 before intubation (baseline values). While there was a significant difference after intubation between block group, mean ± sd 72.12 ± 1.77 and non - block group, mean ± sd 74.62 ± 5.07, p-value = 0.02. There was an insignificant difference between (B) and (Non) groups before intubation regarding PI values, while PI was significantly higher in (B) group than the (Non) group after intubation where mean ± sd was 1.17 ± 0.05 versus 0.96 ± 0.09, respectively, p-value = 0.001. There was no significant difference regarding cerebral oxygenation between the groups. CONCLUSIONS SPGB can control factors that increase CBF during anaesthesia by the block of parasympathetic vasodilatory fibres to the arterial system in the anterior cerebral circulation, while neither hindering cerebral venous drainage nor impairing cerebral oxygenation, as it gives no supply to cerebral veins and does not affect basal CBF. Additionally, it does not affect systemic circulation.
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Affiliation(s)
- Naglaa Fathy Abdelhaleem
- Anaesthesia and Surgical Intensive Care department, Faculty of Human Medicine, Zagazig University, Zagazig 44519, Egypt.
| | - Youssef Essam Mohamed
- Neurosurgery department, Faculty of Human Medicine, Zagazig University, Zagazig 44519, Egypt
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