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Background: Head elevation is recommended as a tier zero measure to decrease high intracranial pressure (ICP) in neurocritical patients. However, its quantitative effects on cerebral perfusion pressure (CPP), jugular bulb oxygen saturation (SjvO2), brain tissue partial pressure of oxygen (PbtO2), and arteriovenous difference of oxygen (AVDO2) are uncertain. Our objective was to evaluate the effects of head elevation on ICP, CPP, SjvO2, PbtO2, and AVDO2 among patients with acute brain injury. Methods: We conducted a systematic review and meta-analysis on PubMed, Scopus, and Cochrane Library of studies comparing the effects of different degrees of head elevation on ICP, CPP, SjvO2, PbtO2, and AVDO2. Results: A total of 25 articles were included in the systematic review. Of these, 16 provided quantitative data regarding outcomes of interest and underwent meta-analyses. The mean ICP of patients with acute brain injury was lower in group with 30° of head elevation than in the supine position group (mean difference [MD] − 5.58 mm Hg; 95% confidence interval [CI] − 6.74 to − 4.41 mm Hg; p < 0.00001). The only comparison in which a greater degree of head elevation did not significantly reduce the ICP was 45° vs. 30°. The mean CPP remained similar between 30° of head elevation and supine position (MD − 2.48 mm Hg; 95% CI − 5.69 to 0.73 mm Hg; p = 0.13). Similar findings were observed in all other comparisons. The mean SjvO2 was similar between the 30° of head elevation and supine position groups (MD 0.32%; 95% CI − 1.67% to 2.32%; p = 0.75), as was the mean PbtO2 (MD − 1.50 mm Hg; 95% CI − 4.62 to 1.62 mm Hg; p = 0.36), and the mean AVDO2 (MD 0.06 µmol/L; 95% CI − 0.20 to 0.32 µmol/L; p = 0.65).The mean ICP of patients with traumatic brain injury was also lower with 30° of head elevation when compared to the supine position. There was no difference in the mean values of mean arterial pressure, CPP, SjvO2, and PbtO2 between these groups. Conclusions: Increasing degrees of head elevation were associated, in general, with a lower ICP, whereas CPP and brain oxygenation parameters remained unchanged. The severe traumatic brain injury subanalysis found similar results. [ABSTRACT FROM AUTHOR]

Neurocritical patients frequently exhibit abnormalities in cerebral hemodynamics (CH) and/or intracranial compliance (ICC), all of which significantly impact their clinical outcomes. Transcranial Doppler (TCD) and the cranial micro-deformation sensor (B4C) are valuable techniques for assessing CH and ICC, respectively. However, there is a scarcity of data regarding the predictive value of these techniques in determining patient outcomes. We prospectively included neurocritical patients undergoing intracranial pressure (ICP) monitoring within the first 5 days of hospital admission for TCD and B4C assessments. Comprehensive clinical data were collected alongside parameters obtained from TCD (including the estimated ICP [eICP] and estimated cerebral perfusion pressure [eCPP]) and B4C (measured as the P2/P1 ratio). These parameters were evaluated individually as well as in combination. The short-term outcomes (STO) of interest were the therapy intensity levels (TIL) for ICP management recommended by the Seattle International Brain Injury Consensus Conference, as TIL 0 (STO 1), TIL 1–3 (STO 2) and death (STO 3), at the seventh day after last data collection. The dataset was randomly separated in test and training samples, area under the curve (AUC) was used to represent the noninvasive techniques ability on the STO prediction and association with ICP. A total of 98 patients were included, with 67% having experienced severe traumatic brain injury and 15% subarachnoid hemorrhage, whilst the remaining patients had ischemic or hemorrhagic stroke. ICP, P2/P1, and eCPP demonstrated the highest ability to predict early mortality (p = 0.02, p = 0.02, and p = 0.006, respectively). P2/P1 was the only parameter significant for the prediction of STO 1 (p = 0.03). Combining B4C and TCD parameters, the highest AUC was 0.85 to predict death (STO 3), using P2/P1 + eCPP, whereas AUC was 0.72 to identify ICP > 20 mmHg using P2/P1 + eICP. The combined noninvasive neuromonitoring approach using eCPP and P2/P1 ratio demonstrated improved performance in predicting outcomes during the early phase after acute brain injury. The correlation with intracranial hypertension was moderate, by means of eICP and P2/P1 ratio. These results support the need for interpretation of this information in the ICU and warrant further investigations for the definition of therapy strategies using ancillary tests. Trial registration: NCT03144219, Registered 01 May 2017, https://www.clinicaltrials.gov/ct2/show/NCT03144219. Highlights: Noninvasive methods as transcranial Doppler and a cranial pulsation sensor provided pathophysiological parameters which may be associated with poorer outcomes in acute brain injury. P2/P1 ratio, eICP and eCPP demonstrated high negative predictive values for ruling out either intracranial hypertension or imminence of death. The combination of these techniques was important to improve their predictive value, rather than using them separately. The strong correlation of these parameters with outcomes but only moderate correlation with intracranial pressure values seems to reinforce the need for a physiological and dynamic reasoning when dealing with neurocritical patients and monitoring ICP. [ABSTRACT FROM AUTHOR]

The time constant of the cerebral arterial bed (τ) represents an estimation of the transit time of flow from the point of insonation at the level of the middle cerebral artery to the arteriolar-capillary boundary, during a cardiac cycle. This study assessed differences in τ among healthy volunteers across different age groups. Simultaneous recordings of transcranial Doppler cerebral blood flow velocity (CBFV) and arterial blood pressure (ABP) were performed on two groups: young volunteers (below 30 years of age), and older volunteers (above 40 years of age). τ was estimated using mathematical transformation of ABP and CBFV pulse waveforms. 77 healthy volunteers [52 in the young group, and 25 in the old group] were included. Pulse amplitude of ABP was higher [16.7 (14.6–19.4) mmHg] in older volunteers as compared to younger ones [12.5 (10.9–14.4) mm Hg; p < 0.001]. CBFV was lower in older volunteers [59 (50–66) cm/s] as compared to younger ones [72 (63–78) cm/s p < 0.001]. τ was longer in the younger volunteers [217 (168–237) ms] as compared to the older volunteers [183 (149–211) ms; p = 0.004]. τ significantly decreased with age (rS = − 0.27; p = 0.018). τ is potentially an integrative marker of the changes occurring in cerebral vasculature, as it encompasses the interplay between changes in compliance and resistance that occur with age. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to investigate whether the spatial coefficient of variation of arterial spin labeling (ASL-CoV) acquired in clinical settings can be used to estimate decreased cerebrovascular reactivity (CVR) measured with single-photon emission computed tomography (SPECT) and acetazolamide challenge in patients with atherosclerotic stenosis of intra- or extracranial arteries. Methods: We evaluated the data of 27 atherosclerotic stenosis patients who underwent pseudocontinuous ASL and SPECT. After spatial normalization, regional values were measured using the distributed middle cerebral artery territorial atlas of each patient. We performed comparisons, correlations, and receiver operating characteristic (ROC) curve analyses between ASL-cerebral blood blow (CBF), ASL-CoV, SPECT-CBF and SPECT-CVR. Results: Although the ASL-CBF values were positively correlated with SPECT-CBF values (r = 0.48, 95% confidence interval (CI) = 0.28–0.64), no significant difference in ASL-CBF values was detected between regions with and without decreased CVR. However, regions with decreased CVR had significantly greater ASL-CoV values than regions without decreased CVR. SPECT-CVR was negatively correlated with ASL-CoV (ρ = -0.29, 95% CI = -0.49 - -0.06). The area under the ROC curve of ASL-CoV in predicting decreased CVR (0.66, 95% CI = 0.51–0.81) was greater than that of ASL-CBF (0.51, 95% CI = 0.34–0.68). An ASL-CoV threshold value of 42% achieved a high specificity of 0.93 (sensitivity = 0.42, positive predictive value = 0.77, and negative predictive value = 0.75). Conclusion: ASL-CoV acquired by single postlabeling delay without an acetazolamide challenge may aid in the identification of patients with decreased CVR on SPECT. [ABSTRACT FROM AUTHOR]

SignificanceStudying cerebral hemodynamics may provide diagnostic information on neurological conditions. Wide-field imaging techniques, such as laser speckle imaging (LSI) and optical intrinsic signal imaging, are commonly used to study cerebral hemodynamics. However, they often do not account appropriately for the optical properties of the brain that can vary among subjects and even during a single measurement. Here, we describe the combination of LSI and spatial-frequency domain imaging (SFDI) into a wide-field quantitative hemodynamic imaging (QHI) system that can correct the effects of optical properties on LSI measurements to achieve a quantitative measurement of cerebral blood flow (CBF).AimWe describe the design, fabrication, and testing of QHI.ApproachThe QHI hardware combines LSI and SFDI with spatial and temporal synchronization. We characterized system sensitivity, accuracy, and precision with tissue-mimicking phantoms. With SFDI optical property measurements, we describe a method derived from dynamic light scattering to obtain absolute CBF values from LSI and SFDI measurements. We illustrate the potential benefits of absolute CBF measurements in resting-state and dynamic experiments.ResultsQHI achieved a 50-Hz raw acquisition frame rate with a 10×10  mm field of view and flow sensitivity up to ∼4  mm/s. The extracted SFDI optical properties agreed well with a commercial system (R2≥0.98). The system showed high stability with low coefficients of variations over multiple sessions within the same day (

We assessed the feasibility of concurrent monitoring of cerebral hemodynamics in adult, comatose out-of-hospital cardiac arrest (OHCA) patients admitted to the National University Heart Centre Singapore from October 2021 to August 2023. Patients underwent continuous near-infrared spectroscopy (NIRS) monitoring in the first 72 h after return of spontaneous circulation (ROSC) and 30-min transcranial Doppler ultrasound (TCD) monitoring at least once. With constant mechanical ventilatory settings and continuous electrocardiographic, pulse oximeter and end-tidal carbon dioxide monitoring, blood pressure was manipulated via vasopressors and cerebral autoregulation assessed by measuring changes in regional cerebral oxygenation (NIRS) and cerebral blood flow velocities (TCD) in response to changes in mean arterial pressure. The primary outcome was neurological recovery at hospital discharge. Amongst the first 16 patients (median age 61, 94% males), we observed four unique patterns: preserved cerebral autoregulation, loss of cerebral autoregulation, cardio-cerebral asynchrony and cerebral circulatory arrest. Patients with preserved cerebral autoregulation had lower levels of neuro-injury biomarkers (neurofilaments light and heavy) and the majority (86%) were discharged with good neurological recovery. Multi-modal assessment of cerebral hemodynamics after OHCA is feasible and derived patterns correlated with neurological outcomes. The between- and within-patient heterogeneity in cerebral hemodynamics calls for more research on individualized treatment strategies. [ABSTRACT FROM AUTHOR]

Background: Nursing interventions in the care of pediatric patients with severe traumatic brain injury (TBI) can have a direct effect on intracranial pressure (ICP), yet they have been largely underexplored. Early evidence is therefore needed to describe these relationships and to determine intervention that promotes neuroprotection and recovery. Objectives: The aim of this study was to examine nursing interventions within the first 72 hours of pediatric severe TBI and their effects on ICP. Method: This is a retrospective review of pediatric patients admitted for severe TBI using a quasiexperimental approach to assess nursing interventions and their association with the patients' ICP values prior to and after each intervention. Results: Of the 56 patients who met the inclusion criteria, 3392 intervention events (range, 31-138 events per patient) were reported. Paired t tests conducted for each intervention type found a statistically significant relationship with suctioning and percent change in ICP values (P = .045). All other interventions showed no significant differences. Discussion: Standard nursing interventions, specifically suctioning, in pediatric severe TBI may affect ICP and therefore neuroprotection. Further work is needed to better understand the role and timing of nursing interventions and their influence on cerebral hemodynamics so that future TBI guidelines consider nursing care and their impact on brain injury recovery. [ABSTRACT FROM AUTHOR]

Purpose: Cerebral hemodynamics are important for the management of intracranial atherosclerotic stenosis (ICAS). The quantitative flow ratio (QFR) is a novel angiography-derived index for assessing the functional relevance of ICAS without pressure wires and adenosine. Good diagnostic yield with the hyperemic fractional flow reserve (FFR) have been reported, while data on the comparison of QFR to FFR are scarce. Methods: In this prospective study 56 patients with anterior circulation symptomatic ICAS who received endovascular treatment were included. The new method of computing QFR from a single angiographic view, i.e., the Murray law-based QFR (μQFR), was applied to the examined vessels. An artificial intelligence algorithm was developed to realize the automatic delineation of vascular contour. Pressure gradients were measured before and after treatment within the lesion vessel using a pressure guidewire and the FFR was calculated. Results: There was a good correlation between μQFR and FFR. Preoperative FFR predicted DWI watershed infarction (FFR optimal cut-off level: 0.755). Preoperative μQFR predicted DWI watershed infarction (μQFR optimal cut-off level: 0.51). Preoperative FFR predicted CTP hypoperfusion (FFR best predictive value: 0.62). Preoperative μQFR predicted CTP hypoperfusion (μQFR best predictive value: 0.375). Conclusion: The μQFR based on DSA images can be used as an indicator to assess the functional status of the lesion in patients with ICAS. [ABSTRACT FROM AUTHOR]

Objective: To observe the effect of electromyographic biofeedback therapy combined with Wenyang tongluo acupuncture on cerebral hemodynamics and serum nerve factors in children with spastic cerebral palsy. Methods: 135 children with spastic cerebral palsy admitted to Xi’an TCM Hospital of Encephalopathy from April 2021 to May 2023 were divided into control group and combined group according to the random number table method, 67 cases and 68 cases respectively. Control group received electromyographic biofeedback therapy, and combined group received Wenyang tongluo acupuncture on the basis of control group. The spasm, movement, balance function, lower limb muscle strength, cerebral hemodynamics and serum nerve factors were compared between two groups. Results: The improvement of spasm condition in combined group was better than that in control group 3 months after treatment (P＜0.05). The scores of Gross Motor Function Measure (GMFM) and Berg Balance Scale (BBS) in combined group were higher than those in control group 3 months after treatment (P＜0.05). The abductor strength of hip joint, flexor strength of knee joint and extensor strength of knee joint in combined group were higher than those in control group 3 months after treatment (P＜0.05). The arterial systolic peak flow velocity and mean blood flow velocity in combined group were higher than those in control group, and the vascular pulsatility index and vascular resistance index were lower than those in control group 3 months after treatment (P＜0.05). The nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) in combined group were higher than those in control group 3 months after treatment (P＜0.05). Conclusion: The combination of wenyang tongluo acupuncture and electromyographic biofeedback therapy in the treatment of children with spastic cerebral palsy, which can effectively improve the spasm, improve the muscle strength and balance function of lower limbs, and improve the cerebral hemodynamics and serum nerve factor levels of the body. [ABSTRACT FROM AUTHOR]

Perfusion Computed Tomography (PCT) is an alternative tool to assess cerebral hemodynamics during trauma. As acute traumatic subdural hematomas (ASH) is a severe primary injury associated with poor outcomes, the aim of this study was to evaluate the cerebral hemodynamics in this context. Five adult patients with moderate and severe traumatic brain injury (TBI) and ASH were included. All individuals were indicated for surgical evacuation. Before and after surgery, PCT was performed and cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) were evaluated. These parameters were associated with the outcome at 6 months post-trauma with the extended Glasgow Outcome Scale (GOSE). Mean age of population was 46 years (SD: 8.1). Mean post-resuscitation Glasgow coma scale (GCS) was 10 (SD: 3.4). Mean preoperative midline brain shift was 10.1 mm (SD: 1.8). Preoperative CBF and MTT were 23.9 ml/100 g/min (SD: 6.1) and 7.3 s (1.3) respectively. After surgery, CBF increase to 30.7 ml/100 g/min (SD: 5.1), and MTT decrease to 5.8s (SD:1.0), however, both changes don't achieve statistically significance (p = 0.06). Additionally, CBV increase after surgery, from 2.34 (SD: 0.67) to 2.63 ml/100 g (SD: 1.10), (p = 0.31). Spearman correlation test of postoperative and preoperative CBF ratio with outcome at 6 months was 0.94 (p = 0.054). One patient died with the highest preoperative MTT (9.97 s) and CBV (4.51 ml/100 g). CBF seems to increase after surgery, especially when evaluated together with the MTT values. It is suggested that the improvement in postoperative brain hemodynamics correlates to favorable outcome. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the effect of intravenous MgSO4 on maternal cerebral hemodynamics as well as the association between altered Doppler indices of the ophthalmic arteries and ocular lesions in patients with preeclampsia. Methods: After each of the 15 included patients was diagnosed with preeclampsia, MgSO4 was infused followed by transcranial Doppler tests of the indices of the ophthalmic, anterior, middle, posterior cerebral, vertebral, and basilar arteries, followed by a second MgSO4 infusion. The peak, mean, diastolic velocity, and pulsatile and resistance indices of each artery were automatically measured during testing. Based on the emergent data, the cerebral perfusion pressure, resistance-area product, and cerebral flow index were calculated. Results: The cerebral perfusion pressure of the posterior cerebral arteries significantly decreased following the infusion of MgSO4 (p < 0.05). Before the infusion of MgSO4, cerebral perfusion pressure and cerebral flow index of the ophthalmic arteries were significantly increased (p < 0.05) in the preeclamptic pregnant patients with ocular lesions compared those without ocular lesions. After the infusion of MgSO4, the cerebral perfusion pressure and cerebral flow index of both ophthalmic arteries were slightly decreased, but the difference was not significant. Conclusions: Altered Doppler indices following the infusion of MgSO4 suggest significant changes in the hemodynamics of the posterior cerebral and ophthalmic arteries that are particularly related to the neurological signs and symptoms of women with preeclampsia. These findings may improve the understanding of the mechanism of the cerebral complications of preeclampsia. Advancing comprehension of these underlying mechanisms is postulated to play a pivotal role in the mitigation of hypertensive encephalopathy associated with preeclampsia. [ABSTRACT FROM AUTHOR]

Insomnia, affecting the quality of life of millions globally, necessitates urgent and effective treatment strategies. This study conducted a randomized controlled trial to compare traditional and novel treatment methods in a cohort of 60 insomnia patients. Sleep quality and symptoms were assessed using the Pittsburgh Sleep Quality Index (PSQI), Insomnia Severity Index (ISI), and Dysfunctional Beliefs and Attitudes about Sleep Scale (DBAS). Additionally, transcranial Doppler (TCD) technology was employed to measure cerebral hemodynamic parameters. We divided the patients into two groups for insomnia treatment: (1) Control group: oral administration of zopiclone tablets; (2) Treatment group: oral administration of WuMei Decoction. The findings revealed that novel treatment approaches significantly improved sleep quality, disturbances, daytime functionality, and cerebral hemodynamic indicators. Furthermore, identifying 220 potential target genes through systems biology approaches offers new insights into the molecular mechanisms of insomnia and opportunities for drug development.

A recent publication in JCBFM, "Static autoregulation in humans" gives rise to critical comments. Autoregulation of cerebral blood flow implies that flow is rather constant within a certain blood pressure (BP) range with a lower and an upper pressure limit. The physiology at the two limits is very different, making comparison of the brain's vulnerability at the limits questionable. The recent publication in JCBFM claims a narrow autoregulatory range based on pooling of data from several studies. However, we argue that such pooling blurs the autoregulatory limits. We summarize the classical literature, therefrom we argue for a broad autoregulatory range. [ABSTRACT FROM AUTHOR]

"Objective To investigate the correlation between cerebral hemodynamics, serum indoleamine 2,3-dioxygenase (IDO) and post-stroke cognitive impairment (PSCI), and to explore the predictive value of IOD for PSCI. Methods A total of 50 patients with acute ischemic stroke who were diagnosed and the onset being not more than 7 days in the Department of Neurology of the 900th Hospital of PLA Joint logistics Support Force from July 2020 to June 2021 were selected as the case group. According to the presence or absence of PSCI, the patients were divided into PSCI group (n=30) and non-PSCI (PSNCI) group (n=20), and 50 healthy individuals during the same period were selected as the control group (n=50). ELISA was used to detect the serum IDO levels of the enrolled population. Transcranial color Doppler ultrasound (TCCD) breath-holding test was performed and relevant data was recorded, breath holding index (BHI) was calculated as an evaluation index of cerebral hemodynamics. ROC curve was used to analyze the predictive efficacy of IDO level on PSCI. Results There were statistically significant differences in serum levels of D-dimer and N-terminal pro-brain natriuretic peptide (NT-proBNP) among the three groups (P＜0.05). The serum IDO levels in the control group, PSNCI group, and PSCI group were (0.23±0.05), (0.25±0.02), and (0.31±0.03) ng/mL, respectively, with statistically significant differences among the three groups (F=41.092, P＜0.01). Compared with the PSNCI group, the PSCI group showed an increase in IDO levels (P＜0.05), while there was no statistically significant difference in D-dimer and NT-proBNP levels (P＞0.05). There was no significant difference in BHI among the three groups (P＞0.05). No significant difference was found in lesion location between the PSCI group and the PSNCI group (χ2=15.478, P=0.113). The predictive efficacy was highest when the IDO level cutoff value was 0.277 ng/mL, with a area under the ROC curve (AUC) of 0.938, sensitivity of 83.3%, and specificity of 95.0%. Conclusion There is a significant correlation between serum IDO levels and PSCI, but the relationship between hemodynamic indicators and the occurrence of PSCI is still unclear. Early detection of IDO levels after acute ischemic stroke is helpful for the early identification and diagnosis of PSCI."

To study the effects of ginkgolide injection combined with citicoline sodium tablets on cerebral hemodynamics, oxidative stress and serum monocyte chemoattractant protein-1 (MCP-1) and lipoprotein-associated phospholipase A2 (Lp-PLA2) in patients with cerebral infarction convalescence. According to the random number table method, 146 patients with cerebral infarction convalescence in The First Affiliated Hospital of Anhui University of Traditional Chinese Medicine were divided into control group (n=73, treated with conventional therapy and citicoline sodium tablets) and study group (n=73, combined with ginkgolide injection on the basis of the control group). The clinical efficacy, Barthel index (BI) score, National Institutes of Health Stroke Scale (NIHSS) score, cerebral hemodynamics indicators, serum oxidative stress indicators, MCP-1, Lp-PLA2 and medication safety were compared between two groups. Compared with the 82.19% clinical total effective rate in control group, the 97.26% in study group was higher (P<0.05). After treatment, BI score, mean blood flow velocity (Vm), serum superoxide dismutase (SOD) and catalase (CAT) in study group were higher than those in control group, and NIHSS score, pulsatility index (PI), resistance index (RI), serum reactive oxygen species (ROS), serum MCP-1 and Lp-PLA2 were lower than those in control group (P<0.05). There was no difference in the incidence of adverse reactions between two groups(P>0.05). Ginkolide injection combined with citicoline sodium tablets can reduce neurological function damage in patients with cerebral infarction convalescence, improve cerebral hemodynamics, reduce oxidative stress, regulate serum MCP-1 and Lp-PLA2 levels, and have good drug safety [ABSTRACT FROM AUTHOR]

Objective To explore the efficacy of probucol combined with edaravone in patients with cerebral ischemic stroke ( CIS), and the influence on their hemodynamics and neurological function. Methods We retrospectively selected 82 CIS patients as research subjects; they were divided into control group and observation group according to different therapeutic regimens, each with 41 cases. The control group was treated with edaravone while the observation group was treated with edaravone plus probucol. Patients of the two groups were continuously reated for 14 days. The clinical efficacy, National Institute of Health stroke scale (NIHSS) score, modified Barthel index (mBI), mini-mental state examination (MMSE) score, the average velocity (Vm), difference in symmetry of peak flow velocity (DVp), difference in symmetry of average flow velocity (DVm) and peak flow rate (Vp) of the middle cerebral artery, serum Occludin, high sensitivity C reactive protein (hs-CRP), matrix metalloproteinase (MMP)-9 and omentin-1, and the occurrence of adverse reactions were compared between the two groups. Results The total effective rate of the observation group was higher than that of the control group after treatment (92. 68% vs. 75. 61%,P<0. 05). The mBI and MMSE scores of the observation group were higher than those of the control group after treatment while NIHSS score was lower ( P < 0. 01); the Vm and Vp of the middle cerebral artery, and omentin-1 level were all higher than those of the control group while DVp, DVm, and serum Occludin, hs-CRP and MMP-9 levels were all lower than those of the control group (P<0. 05). The incidence of adverse reactions did not vary significantly between the two groups ( P > 0. 05). Conclusion Probucol combined with edaravone shows definite efficacy on CIS, which improves patients􀆳 cerebral hemodynamics, inhibits inflammatory reaction, and relieves neural dysfunction with high safety. [ABSTRACT FROM AUTHOR]

Introduction: Calcitonin gene-related peptide (CGRP) plays an important role in cerebral vasodilation, so here we aim to quantify the impact of CGRP monoclonal antibody (mAb) therapy on cerebral hemodynamics. Methods: In 23 patients with chronic and episodic migraine, cerebral hemodynamic monitoring was performed (1) prior to and (2) 3-months into CGRP-mAb therapy. Transcranial Doppler monitored cerebral blood flow velocity (CBFv) in the middle cerebral artery (MCA) and posterior cerebral artery (PCA), from which cerebrovascular reactivity (CVR) and cerebral autoregulation (CA; Mx-index) were calculated. Results: CA was similar off and on treatment, in the MCA (p = 0.42) and PCA (p = 0.72). CVR was also unaffected by treatment, in the MCA (p = 0.38) and PCA (p = 0.92). CBFv and blood pressure were also unaffected. The subgroup of clinical responders (>50% reduction in migraine frequency) exhibited a small reduction in MCA-CBFv (6.0cm/s; IQR: 1.1-12.4; p = 0.007) and PCA-CBFv (8.9 cm/s; IQR: 6.9-10.3; p = 0.04). Discussion: Dynamic measures of cerebrovascular physiology were preserved after 3 months of CGRP-mAb therapy, but a small reduction in CBFv was observed in patients who responded to treatment. Subgroup findings should be interpreted cautiously, but further investigation may clarify if CBFv is dependent on the degree of CGRP inhibition or may serve as a biomarker of drug sensitivity. [ABSTRACT FROM AUTHOR]

Objective To explore the efficacy of combination therapy of Ginkgo biloba injection and donepezil in the treatment of Alzheimer's disease (AD) based on cerebral hemodynamics and inflammatory factors. Methods A total of 90 patients with AD in Zhangjiakou Shalingzi Hospital from March 2020 to January 2022 were randomly divided into a control group ( 45 cases) and a study group (45 cases) . Both groups received the conventional symptomatic treatment. On this basis, the control group was given donepezil treatment, and the study group was given ginkgo leaf injection combined with donepezil treatment. The therapeutic effects, cerebral hemodynamic parameters [mean flow velocity (MFV) and pulsatility index (PI) of bilateral middle cerebral arteries (bilateral MCA) and basilar arteries (BA)], inflammatory factors [interleukin-6 (IL-6), tumor necrosis factorα (TNF-α), IL-1β], s100β protein, Aβ-amyloid 1-42 ( Aβ1-42), bradykinin (BK), cognitive function, activities of daily living, and adverse reactions were compared between the two groups. Results Compared with the control group (77.78%), the total effective rate of the study group (93.33%) was significantly improved (P < 0.05); 1, 3, and 6 months after the treatment, the MFV of BA and bilateral MCA in the study group was higher than that in the control group, while the PI of BA and bilateral MCA was lower than that in the control group (P < 0.05); The levels of serum TNF-α, IL-6, and IL-1β in the study group were lower than those in the control group 1, 3, and 6 months after the treatment (P < 0.05); 1, 3, and 6 months after the treatment, the levels of serum s100β protein, Aβ1-42, and BK in the study group were lower than those in the control group（P< 0.05); 1, 3, and 6 months after the treatment, the score of the mini-mental state examination scale (MMSE) in the study group was higher than that in the control group, while the scores of the AD assessment subscale cognitive scale (ADAS-cog) and activities of daily living scale (ADL) were lower than those in the control group (P < 0.05); The incidence of adverse reactions in the study group (13.33%) was not significantly different from that in the control group (8.89%) (P > 0.05). Conclusion The efficacy of ginkgo biloba injection combined with donepezil in the treatment of AD is significant, which may be achieved by improving cerebral hemodynamics, downregulating inflammatory factors, and regulating the levels of serum s100β protein, Aβ1-42, and BK. [ABSTRACT FROM AUTHOR]

The association between cerebral hemodynamics and cognitive impairment has been reported in neurodegenerative and cerebrovascular disorders (CVD). However, it is still unclear whether changes occur in the acute phase of CVD. Here we investigated cognitive and hemodynamic parameters and their association in patients with CVD during the acute and subacute phases. Seventy-three patients with mild stroke, not undergoing endovascular treatment, were recruited. All subjects were devoid of intracranial or external carotid stenosis, significant chronic cerebrovascular pathology, dementia or non-compensated cardiovascular diseases. Patients were evaluated within 7 days from symptoms onset (T1) and after 3 months (T2). Clinical and demographic data were collected. NIHSS, MoCA, FAB, and Word-Color Stroop test (WCST) were used to evaluate disease severity and cognitive functions. Basal hemodynamic parameters in the middle cerebral artery were measured with transcranial Doppler. Differences between T2 and T1, correlations between cognitive and hemodynamic variables at T1 and T2, as well as correlations between the T2-T1 variation in cognitive and hemodynamic parameters were assessed. At T1, cognitive performance of MoCA, FAB, and WCST was lower compared with T2; and pulsatility index, a parameter reflecting distal vascular resistance, was higher. However, no correlations between the changes in cognitive and hemodynamic variables were found; therefore, the two seems to be independent phenomena. In the acute phase, the linear association between cerebral blood flow and cognitive performances was lost, probably due to a differential effect of microenvironment changes and vascular-specific phenomena on cognition and cerebral hemodynamics. This relationship was partially restored in the subacute phase. [ABSTRACT FROM AUTHOR]

High-intensity interval training (HIIE) may present unique challenges to the cerebrovascular system in individuals post-stroke. We hypothesized lower middle cerebral artery blood velocity (MCAv) in individuals post-stroke: 1) during 10 minutes of HIIE, 2) immediately following HIIE, and 3) 30 minutes after HIIE, compared to age- and sex-matched controls (CON). We used a recumbent stepper submaximal exercise test to determine workloads for high-intensity and active recovery. Our low volume HIIE protocol consisted of 1-minute intervals for 10 minutes. During HIIE, we measured MCAv, mean arterial pressure (MAP), heart rate (HR), and end tidal carbon dioxide (PETCO2). We assessed carotid-femoral pulse wave velocity as a measure of arterial stiffness. Fifty participants completed the study (25 post-stroke, 76% ischemic, 32% moderate disability). Individuals post-stroke had lower MCAv during HIIE compared to CON (p = 0.03), which remained 30 minutes after HIIE. Individuals post-stroke had greater arterial stiffness (p = 0.01) which was moderately associated with a smaller MCAv responsiveness during HIIE (r = −0.44). No differences were found for MAP, HR, and PETCO2. This study suggests individuals post-stroke had a lower MCAv during HIIE compared to their peers, which remained during recovery up to 30 minutes. Arterial stiffness may contribute to the lower cerebrovascular responsiveness post-stroke. [ABSTRACT FROM AUTHOR]

Physical exercise (PE) has been proven to be beneficial in patients with cirrhosis; effects in cognitive function and cerebral hemodynamics, are yet to be explored. To evaluate the effects of a PE program (LFN-exercise protocol) in hepatic/cerebral hemodynamics. Randomized open clinical trial in patients with cirrhosis; Control: Diet(n = 13),Intervention: Diet + exercise(n = 14) for 12 weeks. Patients received an educational session, mental exercises (printed book and sudoku), and high-protein diet. Exercise intervention consisted of walking 4 times/week with an intensity rated between 12 and 14 on the Borg scale, monitored through bracelet accelerometers. Patients received weekly text messages to encourage adherence and had monthly in-person visits. Patients were mainly Child-Pugh A(88.9 %), median MELD 8(8–10), mean age 53±8 years. In the exercise group the number of steps increased from 9667±3008 to 11,931±4463 (p = 0.002), vs 8004±3224 to 8903±3504 (p = 0.053) in controls. Exercise decreased HVPG from 11(8–14) to 8(6–11)mmHg (p = 0.032) vs no change in the control group from 14(12–16) to 15(11–17)mmHg (p = 0.959). Intervention group showed better cerebral hemodynamics, cognitive function, nutritional status and quality of life after the intervention. Adherence was >90 %, with no adverse events. The LFN-exercise protocol improves portal hypertension, cerebral hemodynamics and cognitive function, as well as nutritional status and quality of life. NCT03932552. [ABSTRACT FROM AUTHOR]

Objective: The role of cerebral microvasculature in cognitive dysfunction can be investigated by identifying the impact of blood flow on cortical tissue oxygenation. In this paper, the impact of capillary stalls on microcirculatory characteristics such as flow and hematocrit (Ht) in the cortical angioarchitecture is studied. Methods: Using a deterministic mathematical model to simulate blood flow in a realistic mouse cortex, hemodynamics parameters, including pressure, flow, vessel diameter‐adjustable hematocrit, and transit time are calculated as a function of stalling events. Results: Using a non‐linear plasma skimming model, it is observed that Ht increases in the penetrating arteries from the pial vessels as a function of cortical depth. The incidence of stalling on Ht distribution along the blood network vessels shows reduction of RBCs around the tissue near occlusion sites and decreased Ht concentration downstream from the blockage points. Moreover, upstream of the occlusion, there is a noticeable increase of the Ht, leading to larger flow resistance due to higher blood viscosity. We predicted marked changes in transit time behavior due to stalls which match trends observed in mice in vivo. Conclusions: These changes to blood cell quantity and quality may be implicated in the development of Alzheimer's disease and contribute to the course of the illness. [ABSTRACT FROM AUTHOR]

Background and purpose: White matter lesions (WMLs) are frequent in sickle cell disease (SCD), with a prevalence described to be as high as 53% by age 30. Cerebrovascular regulation and cardiovascular autonomic regulation, more specifically the sympatho‐vagal balance, can be altered in SCD. In this study the association between WMLs, cerebrovascular regulation and sympatho‐vagal balance was assessed in SCD patients. Methods and results: Sickle cell disease patients with no history of stroke were prospectively evaluated for cerebrovascular reactivity using the breath‐holding test (BHT), the sympatho‐vagal balance (ratio low frequency/high frequency [HF]) using heart rate variability parameters and cerebral autoregulation in the time domain using correlation index Mx, and arterial cerebral compliance based on continuous assessment of cerebral blood flow velocities using transcranial Doppler ultrasound and arterial blood pressure with photo‐plethysmography. WMLs were assessed with magnetic resonance imaging using Fazekas score grading and the presence of lacunes. Forty‐one patients (F/M 25/16) were included. Median age was 37.5 years (19–65). Twenty‐nine (70.7%) patients had SS genotype. Eleven patients had WMLs (26.8%). Patients with WMLs were significantly older (p < 0.001), had a lower HF (p < 0.005) and an impaired cerebral arterial compliance (p < 0.014). The receiver operating curve for the regression model including age and HF showed a higher area under the curve compared to age alone (0.946 vs. 0.876). BHT and Mx did not significantly differ between the two groups. Conclusions: Lower parasympathetic activity and impaired cerebral arterial compliance were associated with WMLs in adults with SCD. This could potentially yield to a better understanding of pathophysiological parameters leading to premature cerebrovascular ageing in SCD. [ABSTRACT FROM AUTHOR]

There may be different mechanisms underlying internal (IBZ) and cortical (CBZ) borderzone infarcts in intracranial atherosclerotic stenosis. In 84 patients with symptomatic, 50-99% atherosclerotic stenosis of M1 middle cerebral artery (MCA-M1) with acute borderzone infarcts in diffusion-weighted imaging, we classified the infarct patterns as isolated IBZ (n = 37), isolated CBZ (n = 31), and IBZ+CBZ (n = 16) infarcts. CT angiography-based computational fluid dynamics models were constructed to quantify translesional, post-stenotic to pre-stenotic pressure ratio (PR) in the MCA-M1 lesion. Those with IBZ infarcts were more likely to have a low PR (indicating impaired antegrade flow across the lesion) than those without (p = 0.012), and those with CBZ infarcts were more likely to have coexisting small cortical infarcts (indicating possible embolism) than those without (p = 0.004). In those with isolated IBZ or CBZ infarcts, low PR was independently associated with isolated IBZ infarcts (adjusted odds ratio = 4.223; p = 0.026). These two groups may also have different trajectories in the stroke risks under current medical treatment regimen, with a higher risk of same-territory ischemic stroke recurrence within 3 months in patients with isolated IBZ infarcts than isolated CBZ infarcts (17.9% versus 0.0%; log-rank p = 0.023), but similar risks later in 1 year. [ABSTRACT FROM AUTHOR]

Fluctuating arterial blood pressure during high-intensity interval exercise (HIIE) may challenge dynamic cerebral autoregulation (dCA), specifically after stroke after an injury to the cerebrovasculature. We hypothesized that dCA would be attenuated at rest and during a sit-to-stand transition immediately after and 30 min after HIIE in individuals poststroke compared with age- and sex-matched control subjects (CON). HIIE switched every minute between 70% and 10% estimated maximal watts for 10 min. Mean arterial pressure (MAP) and middle cerebral artery blood velocity (MCAv) were recorded. dCA was quantified during spontaneous fluctuations in MAP and MCAv via transfer function analysis. For sit-to-stand, time delay before an increase in cerebrovascular conductance index (CVCi = MCAv/MAP), rate of regulation, and % change in MCAv and MAP were measured. Twenty-two individuals poststroke (age 60 ± 12 yr, 31 ± 16 mo) and twenty-four CON (age 60 ± 13 yr) completed the study. Very low frequency (VLF) gain (P = 0.02, η2 = 0.18) and normalized gain (P = 0.01, η2 = 0.43) had a group × time interaction, with CON improving after HIIE whereas individuals poststroke did not. Individuals poststroke had lower VLF phase (P = 0.03, η2 = 0.22) after HIIE compared with CON. We found no differences in the sit-to-stand measurement of dCA. Our study showed lower dCA during spontaneous fluctuations in MCAv and MAP following HIIE in individuals poststroke compared with CON, whereas the sit-to-stand response was maintained. NEW & NOTEWORTHY: This study provides novel insights into poststroke dynamic cerebral autoregulation (dCA) following an acute bout of high-intensity interval exercise (HIIE). In people after stroke, dCA appears attenuated during spontaneous fluctuations in mean arterial pressure (MAP) and middle cerebral artery blood velocity (MCAv) following HIIE. However, the dCA response during a single sit-to-stand transition after HIIE showed no significant difference from controls. These findings suggest that HIIE may temporarily challenge dCA after exercise in individuals with stroke. [ABSTRACT FROM AUTHOR]

Background and aims: Myeloproliferative neoplasms (MPN) are rare hematologic diseases that require early diagnosis to prevent thrombotic events. Only a few studies have investigated transcranial Doppler (TCD) ultrasonography among these population groups. Following the PRISMA Guidelines, we reviewed the utility of TCD in Polycythemia vera (PV) and Essential Thrombocytosis (ET) patients in the context of cerebral blood flow and detection of microembolic signals (MES). Methods: This systematic review focuses on the application of TCD in MPN. By incorporating findings from one observational study, one prospective study, and three case reports, the review establishes that while TCD is not a primary tool for diagnosing PV and ET, it plays a crucial role in monitoring cerebrovascular complications, assessing thrombotic risk, evaluating treatment responses, and facilitating research related to these conditions. Results: This review incorporates findings from a total of 63 patients. 3.2% had ischemic stroke and 1.6% had transient ischemic attack with a total of 4.8% stroke risk. Highintensity transient signals (HITS) were common in 22% of patients wherein they had elevated hemoglobin, hematocrit, and platelet values. Following treatment and normalization of blood panels, 31.7% had improved cerebral perfusion with normal flow velocities. 3.2% had elevated flow velocities linked to blood flow obstruction. There was significant clinical improvement among the study population, with 17.5% becoming asymptomatic with the disappearance of MES. Conclusions: The judicious use of TCD can enhance a comprehensive diagnostic and monitoring strategy, complementing traditional clinical and laboratory assessments in the management of MPN specifically PV and ET. [ABSTRACT FROM AUTHOR]

To investigate the effects of tianma gouteng decoction on cerebral hemodynamics, oxidative stress and nerve cell factors in patients with cerebral infarction convalescence. 108 patients with cerebral infarction convalescence who were treated in The Second Affiliated Hospital of Tianjin University of Traditional Chinese Medicine from April 2020 to December 2022were selected, and divided into control group and combined group according to random number table method, with 54 cases in each group. Patients in control group received routine treatment, and patients in combined group received tianma gouteng decoction on the basis of control group. The chinese medicine syndrome scores, cerebral hemodynamics, Barthel index score, oxidative stress index, national institutes of health stroke scale (NIHSS) score and nerve cell factor were compared between two groups. Compared with control group 2 months after treatment, the chinese medicine syndrome scores such as hemianesthesia, hemiplegia, strong tongue, dizziness and headache, red face and red eyes and bitter and dry mouth in combined group were lower (P<0.05). Compared with control group 2months after treatment, the NIHSS score in combined group was lower and the Barthel index score was higher (P<0.05). Compared with control group 2 months after treatment, combined group had lower pulsatility index (PI), higher mean blood flow velocity (Vm) and peak systolic blood flow velocity (Vs) (P<0.05). Compared with control group 2 months after treatment, combined group had lower malondialdehyde (MDA) and higher superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) (P<0.05). Compared with control group2 months after treatment, combined group had lower myelin basic protein (MBP), higher nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) (P<0.05). Modified tianma gouteng decoction can promote the improvement of clinical symptoms, reduce neurological impairment, improve cerebral hemodynamics, reduce oxidative stress, improve the secretion of nerve cell factors and improve self-care ability in patients with cerebral infarction convalescence. [ABSTRACT FROM AUTHOR]

Cerebral hemodynamics describes an important physiological system affected by components such as blood pressure, CO2 levels, and endothelial factors. Recently, novel techniques have emerged to analyse cerebral hemodynamics based on the calculation of entropies, which quantifies or describes changes in the complexity of this system when it is affected by a pathological or physiological influence. One recently described measure is transfer entropy, which allows for the determination of causality between the various components of a system in terms of their flow of information, and has shown positive results in the multivariate analysis of physiological signals. This study aims to determine whether conditional transfer entropy reflects the causality in terms of entropy generated by hypocapnia on cerebral hemodynamics. To achieve this, non-invasive signals from 28 healthy individuals who undertook a hyperventilation maneuver were analyzed using conditional transfer entropy to assess the variation in the relevance of CO2 levels on cerebral blood velocity. By employing a specific method to discretize the signals, it was possible to differentiate the influence of CO2 levels during the hyperventilation phase (22.0% and 20.3% increase for the left and right hemispheres, respectively) compared to normal breathing, which remained higher during the recovery phase (15.3% and 15.2% increase, respectively). [ABSTRACT FROM AUTHOR]

Purpose: Bacterial meningitis remains a global threat due to its high mortality. It is estimated that >1.2 million cases of bacterial meningitis are reported annually. Intracranial vasculopathy is an important, under‐documented complication, easily detected by transcranial Doppler (TCD) ultrasonography. Following the PRISMA Guidelines, we reviewed the utility of TCD in bacterial meningitis. Methods: This is a systematic review of observational studies on the use of TCD in patients with CSF‐proven bacterial meningitis. Characteristic changes in TCD parameters along the course of the disease, correlation of TCD findings with neuroimaging, and functional outcomes were evaluated. Results: Nine studies were included with a total of 492 participants (mean age of 42). The most common TCD finding was intracranial arterial stenosis of the MCA (50%–82%) and ischemia (33%) was the predominant neuroimaging finding. The presence of an abnormal TCD finding increased the risk of poor outcomes as high as 70%. Conclusions: Patients diagnosed with bacterial meningitis who underwent TCD show alterations in cerebral blood flow, correlating with imaging findings and poor outcomes. It aids in the diagnosis of its sequelae and can predict the prognosis of its outcome. TCD is a cost‐effective, reliable modality for diagnosing vasculopathy associated with bacterial meningitis. It may prove useful in our armamentarium of management. Large prospective studies with long‐term follow‐up data may help establish the use of TCD in bacterial meningitis. [ABSTRACT FROM AUTHOR]

Background: Cranioplasty has been useful in treating the symptoms associated with the "Sunken skin flap syndrome" post decompressive craniectomy, for which various mechanisms have been proposed. In this study, we aim to assess the changes in the cerebral blood flow and intracranial cerebrospinal fluid (CSF) dynamics post cranioplasty and correlate with the improvement in the neurocognitive status. Methods: Computed tomography perfusion and cine magnetic resonance imaging studies were done to study the changes in cerebral perfusion and CSF flow dynamics postcranioplasty. The cognitive status was assessed using Montreal cognitive assessment, mini-mental state examination, and frontal assessment battery scores in the preoperative period and at 1 and 6 months follow-up. Results: There was a significant change in cognitive status postcranioplasty, both at 1 and 6 months follow-up, which was associated with a significant improvement in cerebral blood flow, decreased mean transit time, and improvement in the mean and peak CSF flow velocities at the foramen of Magendie and aqueduct of Sylvius. Conclusion: Cranioplasty leads to a marked improvement in cerebral hemodynamics, which is more significant on the ipsilateral side. It also leads to increased CSF turnover and improved CSF circulation. Improved cerebral perfusion and, more importantly, CSF dynamics may be responsible for the demonstrable improvement in the neurocognition in the postcranioplasty period. [ABSTRACT FROM AUTHOR]

This document provides brief biographical information about two individuals, Wesley B. Baker and Soren Konecky. Wesley B. Baker is an assistant professor at the University of Pennsylvania and Children's Hospital of Philadelphia, specializing in biomedical optical devices to monitor cerebral health. Soren Konecky is the chief technology officer for Openwater, with expertise in optical imaging and algorithm development. Both individuals have extensive experience in their respective fields and have made significant contributions to research and academia. [Extracted from the article]

This research paper discusses the development of a spiral laser scanning photoacoustic microscopy (sLS-PAM) system for functional brain imaging in rats. The aim of the study was to create a high-resolution, fast frame-rate, and wide field-of-view (FOV) PAM system that can capture hemodynamic changes in the brain. The sLS-PAM system was able to image cerebral hemodynamics in response to whisker and electrical stimulation, as well as vascular imaging of a modeled brain injury. The researchers believe that this simple-to-implement PAM system could become an affordable functional neuroimaging tool for researchers. [Extracted from the article]

This research paper explores the use of diffuse correlation spectroscopy (DCS) to measure changes in cerebral blood flow (CBF) in patients with Chiari malformation (CM) compared to healthy controls. The study finds that the augmentation index (AIx) is significantly lower in CM patients, indicating decreased vascular compliance. Age is also found to have a significant impact on AIx, with older individuals having higher values. The study suggests that changes in extravascular compliance may contribute to alterations in the pulsatile waveforms. The findings highlight the importance of considering both vascular and extravascular factors in understanding changes in cerebral blood flow waveforms. [Extracted from the article]

IntroductionCalcitonin gene-related peptide (CGRP) plays an important role in cerebral vasodilation, so here we aim to quantify the impact of CGRP monoclonal antibody (mAb) therapy on cerebral hemodynamics.MethodsIn 23 patients with chronic and episodic migraine, cerebral hemodynamic monitoring was performed (1) prior to and (2) 3-months into CGRP-mAb therapy. Transcranial Doppler monitored cerebral blood flow velocity (CBFv) in the middle cerebral artery (MCA) and posterior cerebral artery (PCA), from which cerebrovascular reactivity (CVR) and cerebral autoregulation (CA; Mx-index) were calculated.ResultsCA was similar off and on treatment, in the MCA (p = 0.42) and PCA (p = 0.72). CVR was also unaffected by treatment, in the MCA (p = 0.38) and PCA (p = 0.92). CBFv and blood pressure were also unaffected. The subgroup of clinical responders (>50% reduction in migraine frequency) exhibited a small reduction in MCA-CBFv (6.0 cm/s; IQR: 1.1–12.4; p = 0.007) and PCA-CBFv (8.9 cm/s; IQR: 6.9–10.3; p = 0.04).DiscussionDynamic measures of cerebrovascular physiology were preserved after 3 months of CGRP-mAb therapy, but a small reduction in CBFv was observed in patients who responded to treatment. Subgroup findings should be interpreted cautiously, but further investigation may clarify if CBFv is dependent on the degree of CGRP inhibition or may serve as a biomarker of drug sensitivity.

BackgroundSpreading depolarizations (SDs) are self-propagating waves of neuronal and glial depolarizations often seen in neurological conditions in both humans and animal models. Because SD is thought to worsen neurological injury, the role of SD in a variety of cerebral insults has garnered significant investigation. Anoxic SD is a type of SD that occurs because of anoxia or asphyxia. Although asphyxia leading to a severe drop in blood pressure may affect cerebral hemodynamics and is widely known to cause anoxic SD, the effect of anoxic SD on peripheral blood pressure in the extremities has not been investigated. This relationship is especially important to understand for conditions such as circulatory shock and cardiac arrest that directly affect both peripheral and cerebral perfusion in addition to producing anoxic SD in the brain.MethodsIn this study, we used a rat model of asphyxial cardiac arrest to investigate the role of anoxic SD on cerebral hemodynamics and metabolism, peripheral blood pressure, and the relationship between these variables in 8- to 12-week-old male rats. We incorporated a multimodal monitoring platform measuring cortical direct current simultaneously with optical imaging.ResultsWe found that during anoxic SD, there is decoupling of peripheral blood pressure from cerebral blood flow and metabolism. We also observed that anoxic SD may modify cerebrovascular resistance. Furthermore, shorter time difference between anoxic SDs measured at different locations in the same rat was associated with better neurological outcome on the basis of the recovery of electrocorticography activity (bursting) immediately post resuscitation and the neurological deficit scale score 24 h post resuscitation.ConclusionsTo our knowledge, this is the first study to quantify the relationship between peripheral blood pressure, cerebral hemodynamics and metabolism, and neurological outcome in anoxic SD. These results indicate that the characteristics of SD may not be limited to cerebral hemodynamics and metabolism but rather may also encompass changes in peripheral blood flow, possibly through a brain-heart connection, providing new insights into the role of anoxic SD in global ischemia and recovery.

Objective: The objective of this retrospective review was to evaluate whether or not pulsatile flow improves cerebral hemodynamics and clinical outcomes in pediatric congenital cardiac surgery patients. Methods: This retrospective study included 284 pediatric patients undergoing congenital cardiac surgery with cardiopulmonary bypass support utilizing nonpulsatile (n = 152) or pulsatile (n = 132) flow. Intraoperative cerebral gaseous microemboli counts, pulsatility index, and mean blood flow velocity at the right middle cerebral artery were assessed using transcranial Doppler ultrasound. Clinical outcomes were compared between groups. Results: Patient demographics and cardiopulmonary bypass characteristics between groups were similar. Although the pulsatility index during aortic crossclamping was consistently higher in the pulsatile group (P

IntroductionSuccessful treatment of intracranial aneurysms after flow diversion (FD) is dependent on the flow modulating effect of the device. We aimed to investigate the intra-aneurysmal and parent vessel hemodynamic changes, as well as the incidence of silent emboli following treatment with various FD devices.MethodsWe evaluated the appearance of the eclipse sign in nine distinct phases of cerebral angiography before and immediately after FD placement in correlation with aneurysm occlusion. Angiographic and clinical data of consecutive procedures were analyzed retrospectively. Patients who had successful FD procedure without adjunctive coiling, visible eclipse sign on post embolization angiography, and reliable follow-up angiographic data were included in the analysis. Detailed analysis of hemodynamic data from transcranial doppler after FD was performed in selected patients, such as monitoring for silent emboli.ResultsAmong all patients (N = 65) who met inclusion criteria, complete aneurysm occlusion at 12 months was achieved in 89% (58/65). Eclipse sign prior to FD was observed in 42% (27/65) with unchanged appearance in 4.6% (3/65) of the treated patients. None of these three patients achieved complete aneurysm occlusion. Among all analyzed variables, such as aneurysm size, device type used, age, and appearance of the eclipse sign pre- and post-FD, the most reliable predictor of permanent aneurysm occlusion at 12 months was earlier, prolonged, and sustained eclipse sign visibility in more than three angiographic phases in comparison to the baseline (p < 0.001). Elevation in flow velocities within the ipsilateral vascular territory was noted in 70% (9/13), and bilaterally in 54% (7/13) of the treated patients. None of the patients had silent emboli.ConclusionsIntra-aneurysmal and parent vessel hemodynamic changes after FD can be reliably assessed by the cerebral angiography and transcranial doppler with important implications for the prediction of successful treatment.

We assessed the feasibility of concurrent monitoring of cerebral hemodynamics in adult, comatose out-of-hospital cardiac arrest (OHCA) patients admitted to the National University Heart Centre Singapore from October 2021 to August 2023. Patients underwent continuous near-infrared spectroscopy (NIRS) monitoring in the first 72 h after return of spontaneous circulation (ROSC) and 30-min transcranial Doppler ultrasound (TCD) monitoring at least once. With constant mechanical ventilatory settings and continuous electrocardiographic, pulse oximeter and end-tidal carbon dioxide monitoring, blood pressure was manipulated via vasopressors and cerebral autoregulation assessed by measuring changes in regional cerebral oxygenation (NIRS) and cerebral blood flow velocities (TCD) in response to changes in mean arterial pressure. The primary outcome was neurological recovery at hospital discharge. Amongst the first 16 patients (median age 61, 94% males), we observed four unique patterns: preserved cerebral autoregulation, loss of cerebral autoregulation, cardio-cerebral asynchrony and cerebral circulatory arrest. Patients with preserved cerebral autoregulation had lower levels of neuro-injury biomarkers (neurofilaments light and heavy) and the majority (86%) were discharged with good neurological recovery. Multi-modal assessment of cerebral hemodynamics after OHCA is feasible and derived patterns correlated with neurological outcomes. The between- and within-patient heterogeneity in cerebral hemodynamics calls for more research on individualized treatment strategies.

Purpose: To evaluate the phenomenological significance of cerebral blood pulsatility imaging in aging research. Methods: N = 38 subjects from 20 to 72 years of age (24 females) were imaged with ultrafast MRI with a sampling rate of 100 ms and simultaneous acquisition of pulse oximetry data. Of these, 28 subjects had acceptable MRI and pulse data, with 16 subjects between 20 and 28 years of age, and 12 subjects between 61 and 72 years of age. Pulse amplitude in the circle of Willis was assessed with the recently developed method of analytic phase projection to extract blood volume waveforms. Results: Arteries in the circle of Willis showed pulsatility in the MRI for both the young and old age groups. Pulse amplitude in the circle of Willis significantly increased with age (p = 0.01) but was independent of gender, heart rate, and head motion during MRI. Discussion and conclusion: Increased pulse wave amplitude in the circle of Willis in the elderly suggests a phenomenological significance of cerebral blood pulsatility imaging in aging research. The physiologic origin of increased pulse amplitude (increased pulse pressure vs. change in arterial morphology vs. re-shaping of pulse waveforms caused by the heart, and possible interaction with cerebrospinal fluid pulsatility) requires further investigation.

Introduction: Electrical-equivalence mathematical models that integrate vascular and cerebrospinal fluid (CSF) compartments perform well in simulations of dynamic cerebrovascular variations and their transient effects on intracranial pressure (ICP). However, ICP changes due to sustained vascular diameter changes have not been comprehensively examined. We hypothesise that changes in cerebrovascular resistance (CVR) alter the resistance of the bulk flow of interstitial fluid (ISF). Research question: We hypothesise that changes in CVR alter the resistance of the bulk flow of ISF, thus allowing simulations of ICP in response to sustained vascular diameter changes. Material and methods: A lumped parameter model with vascular and CSF compartments was constructed and converted into an electrical analogue. The flow and pressure responses to transient hyperaemic response test (THRT) and CSF infusion test (IT) were observed. Arterial blood pressure (ABP) was manipulated to simulate ICP plateau waves. The experiments were repeated with a modified model that included the ISF compartment. Results: Simulations of the THRT produced identical cerebral blood flow (CBF) responses. ICP generated by the new model reacted in a similar manner as the original model during ITs. Plateau pressure reached during ITs was however higher in the ISF model. Only the latter was successful in simulating the onset of ICP plateau waves in response to selective blood pressure manipulations. Discussion and conclusion: Our simulations highlighted the importance of including the ISF compartment, which provides mechanism explaining sustained haemodynamic influences on ICP. Consideration of such interactions enables accurate simulations of the cerebrovascular effects on ICP.

Background: The direct quantitative measurement of donor and recipient pressures in patients with moyamoya vasculopathy (MMV) during superficial temporal artery-middle cerebral artery (STA-MCA) bypass surgery has yet to be reported in academic literature. Method: Using a wireless pressure wire, we describe our approach to measuring seven pressure parameters in MMV patients step-by-step. Conclusion: Direct intraluminal pressure measurement of donor and recipient arteries provides a practical and accurate means to quantify cerebral hemodynamic parameters in MMV patients, enhancing understanding of individualized hemodynamic changes pre- and post-surgery. [ABSTRACT FROM AUTHOR]

Background: Clinically, there is considerable heterogeneity in the presentation of transthyretin amyloidosis (ATTR), which ranges from primarily cardiac and primarily neurologic to mixed disease, among other manifestations. Because of this complex presentation, the diagnosis and management of patients with ATTR are often challenging and should be performed in interdisciplinary centers specialized in amyloidosis. Here, we aimed to increase awareness of ATTR detection and pathophysiology through a multidimensional multiorgan approach. Case report: We reported on a 60-year-old man with wild-type ATTR who underwent a number of both basic and advanced cardiological and neurological investigations at baseline and after a treatment period with the TTR tetramer stabilizer, tafamidis. Several findings are provided here, some of which might be considered instrumental correlates of the patient's clinical improvement after therapy. Conclusions: Adequate awareness and prompt recognition of ATTR support early diagnosis and faster access to therapies, thereby slowing the progression and improving the prognosis. The need for a multidisciplinary alliance between specialists and the opportunity to perform, at least in selected cases, a set of specific examinations for a detailed assessment of ATTR patients can also provide valuable insights into the physiopathology and response to therapy of a disease as complex and intriguing as ATTR. [ABSTRACT FROM AUTHOR]

Unhealthy vascular aging promotes atherogenesis, which may lead to significant internal carotid artery stenosis (CAS) in 5 to 7.5% of older adults. The pathogenic factors that promote accelerated vascular aging and CAS also affect the downstream portion of the cerebral microcirculation in these patients. Primary treatments of significant CAS are eversion endarterectomy or endarterectomy with patch plasty. Factors that determine adequate hemodynamic compensation and thereby the clinical consequences of CAS as well as medical and surgical complications of carotid reconstruction surgery likely involve the anatomy of the circle of Willis (CoW), the magnitude of compensatory inter-hemispheric blood flow, and the effectiveness of cerebral microcirculatory blood flow autoregulation. This study aimed to test two hypotheses based on this theory. First, we hypothesized that patients with symptomatic and asymptomatic CAS would exhibit differences in autoregulatory function and inter-hemispheric blood flow. Second, we predicted that anatomically compromised CoW would associate with impaired inter-hemispheric blood flow compensation. We enrolled older adults with symptomatic or asymptomatic internal CAS (>70% NASCET criteria; n = 46) and assessed CoW integrity by CT angiography. We evaluated transient hyperemic responses in the middle cerebral arteries (MCA) after common carotid artery compression (CCC; 10 s) by transcranial Doppler sonography (TCD). We compared parameters reflecting autoregulatory function (e.g., transient hyperemic response ratio [THRR], return to baseline time [RTB], changes of vascular resistance) and inter-hemispheric blood flow (residual blood flow velocity). Our findings revealed that CAS was associated with impaired cerebral vascular reactivity. However, we did not observe significant differences in autoregulatory function or inter-hemispheric blood flow between patients with symptomatic and asymptomatic CAS. Moreover, anatomically compromised CoW did not significantly affect these parameters. Notably, we observed an inverse correlation between RTB and THRR, and 49% of CAS patients exhibited a delayed THRR, which associated with decreased inter-hemispheric blood flow. Future studies should investigate how TCD-based evaluation of autoregulatory function and inter-hemispheric blood flow can be used to optimize surgical techniques and patient selection for internal carotid artery revascularization. [ABSTRACT FROM AUTHOR]