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Background and purposeCerebral vasomotor reactivity (VMR) is vital for regulating brain blood flow and maintaining neurological function. Impaired cerebral VMR is linked to a higher risk of stroke and poor post-stroke outcomes. This study explores the relationship between statin treatment intensity and VMR in patients with ischemic stroke.MethodsSeventy-four consecutive patients (mean age 69.3 years, 59.4% male) with recent ischemic stroke were included. VMR levels were assessed 4 weeks after the index stroke using transcranial Doppler, measuring the breath-holding index (BHI) as an indicator of the percentage increase in middle cerebral artery blood flow (higher BHI signifies higher VMR). Multistep multivariable regression models, adjusted for demographic and cerebrovascular risk factors, were employed to examine the association between statin intensity treatment and BHI levels.ResultsForty-one patients (55%) received high-intensity statins. Patients receiving high-intensity statins exhibited a mean BHI of 0.85, whereas those on low-intensity statins had a mean BHI of 0.67 (mean difference 0.18, 95% confidence interval: 0.13-0.22, p-value.05). Furthermore, no significant association was found between baseline low-density lipoprotein (LDL) levels and BHI.ConclusionsHigh-intensity statin treatment post-ischemic stroke is linked to elevated VMR independent of demographic and clinical characteristics, including baseline LDL level. Further research is needed to explore statin therapy's impact on preserving brain vascular function beyond lipid-lowering effects.

Purpose: After a traumatic brain injury (TBI), monitoring of both macrovascular and microvascular blood circulation can potentially yield a better understanding of pathophysiology of potential secondary brain lesions. We investigated the changes in phase shift (PS) between cardiac-induced oscillations of cerebral blood flow (CBF) measured at macro (ultrasound Doppler) and microvascular (laser Doppler) level. Further we assessed the impact of intracranial pressure (ICP) on PS in TBI patients. A secondary aim was to compare PS to TCD-derived cerebral arterial time constant (τ), a parameter that reflects the circulatory transit time. Methods: TCD blood flow velocities (FV) in the middle cerebral artery, laser Doppler blood microcirculation flux (LDF), arterial blood pressure (ABP), and ICP were monitored in 29 consecutive patients with TBI. Eight patients were excluded because of poor-quality signals. For the remaining 21 patients (median age = 23 (Q1: 20–Q3: 33); men:16,) data were retrospectively analysed. PS between the fundamental harmonics of FV and LDF signals was determined using spectral analysis. τ was estimated as a product of cerebrovascular resistance and compliance, based on the mathematical transformation of FV and ABP, ICP pulse waveforms. Results: PS was negative (median: −26 (Q1: −38–Q3: −15) degrees) indicating that pulse LDF at a heart rate frequency lagged behind TCD pulse. With rising mean ICP, PS became more negative (R = −0.51, p < 0.019) indicating that delay of LDF pulse increases. There was a significant correlation between PS and cerebrovascular time constant (R = −0.47, p = 0.03). Conclusions: Pulse divergence between FV and LDF became greater with elevated ICP, likely reflecting prolonged circulatory travel time. [ABSTRACT FROM AUTHOR]

Intracranial hypertension (IH) is a life-threating condition especially for the brain injured patient. In such cases, an external ventricular drain (EVD) or an intraparenchymal bolt are the conventional gold standard for intracranial pressure (ICPi) monitoring. However, these techniques have several limitations. Therefore, identifying an ideal screening method for IH is important to avoid the unnecessary placement of ICPi and expedite its introduction in patients who require it. A potential screening tool is the ICP wave morphology (ICPW) which changes according to the intracranial volume-pressure curve. Specifically, the P2/P1 ratio of the ICPW has shown promise as a triage test to indicate normal ICP. In this study, we propose evaluating the noninvasive ICPW (nICPW—B4C sensor) as a screening method for ICPi monitoring in patients with moderate to high probability of IH. This is a retrospective analysis of a prospective, multicenter study that recruited adult patients requiring ICPi monitoring from both Federal University of São Paulo and University of São Paulo Medical School Hospitals. ICPi values and the nICPW parameters were obtained from both the invasive and the noninvasive methods simultaneously 5 min after the closure of the EVD drainage. ICP assessment was performed using a catheter inserted into the ventricle and connected to a pressure transducer and a drainage system. The B4C sensor was positioned on the patient's scalp without the need for trichotomy, surgical incision or trepanation, and the morphology of the ICP waves acquired through a strain sensor that can detect and monitor skull bone deformations caused by changes in ICP. All patients were monitored using this noninvasive system for at least 10 min per session. The area under the curve (AUC) was used to describe discriminatory power of the P2/P1 ratio for IH, with emphasis in the Negative Predictive value (NPV), based on the Youden index, and the negative likelihood ratio [LR-]. Recruitment occurred from August 2017 to March 2020. A total of 69 patients fulfilled inclusion and exclusion criteria in the two centers and a total of 111 monitorizations were performed. The mean P2/P1 ratio value in the sample was 1.12. The mean P2/P1 value in the no IH population was 1.01 meanwhile in the IH population was 1.32 (p < 0.01). The best Youden index for the mean P2/P1 ratio was with a cut-off value of 1.13 showing a sensitivity of 93%, specificity of 60%, and a NPV of 97%, as well as an AUC of 0.83 to predict IH. With the 1.13 cut-off value for P2/P1 ratio, the LR- for IH was 0.11, corresponding to a strong performance in ruling out the condition (IH), with an approximate 45% reduction in condition probability after a negative test (ICPW). To conclude, the P2/P1 ratio of the noninvasive ICP waveform showed in this study a high Negative Predictive Value and Likelihood Ratio in different acute neurological conditions to rule out IH. As a result, this parameter may be beneficial in situations where invasive methods are not feasible or unavailable and to screen high-risk patients for potential invasive ICP monitoring. Trial registration: At clinicaltrials.gov under numbers NCT05121155 (Registered 16 November 2021—retrospectively registered) and NCT03144219 (Registered 30 September 2022—retrospectively registered). [ABSTRACT FROM AUTHOR]

Psoriasis induces systemic atherosclerosis, but its impact on cerebrovascular function remains unclear. However, stroke prevention must be considered in psoriasis, as it is commonly comorbid with classic cardiovascular risk factors. Thus, the aim of the study is to assess cerebral microvasculature function and its confounders in patients with psoriasis. The study protocol included cerebral autoregulation assessment with measurements of vasomotor reactivity reserve (VMRr) on the middle cerebral arteries with the use of a Transcranial Doppler (TCD) in 50 patients with psoriasis without cerebrovascular events (46; 21–74 years) and 26 healthy controls (41; 29–58 years). Analyses of VMRr relationships with the psoriasis course, comorbidities, inflammatory markers and intima–media thickness (IMT) were performed. The study showed that VMRr was lower (64% vs. 76%, p = 0.001), and the IMT was higher (0.65 vs. 0.52 mm, p = 0.001) in patients compared to controls. The patients were also characterized by a higher body mass index (BMI) and a higher level of Il-6 than the controls (29.14 vs. 25.76 kg/m2, p = 0.004 and 585 vs. 204 pg/mL, p < 0.001, respectively), but only BMI was independently impacting VMRr reduction (p = 0.02). In conclusion, early cerebral microvasculature dysfunction may occur in patients with psoriasis, and its extent is associated with an increase in BMI. Thus, body mass reduction should be strongly recommended for stroke prophylaxis in patients with psoriasis. [ABSTRACT FROM AUTHOR]

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. [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]

Background and Purpose: Transcranial Doppler (TCD) identifies acute stroke patients with arterial occlusion where treatment may not effectively open the blocked vessel. This study aimed to examine the clinical utility and prognostic value of TCD flow findings in patients enrolled in a multicenter prospective study (CLOTBUST‐PRO). Methods: Patients enrolled with intracranial occlusion on computed tomography angiography (CTA) who underwent urgent TCD evaluation before intravenous thrombolysis was included in this analysis. TCD findings were assessed using the mean flow velocity (MFV) ratio, comparing the reciprocal ratios of the middle cerebral artery (MCA) depths bilaterally (affected MCA‐to‐contralateral MCA MFV [aMCA/cMCA MFV ratio]). Results: A total of 222 patients with intracranial occlusion on CTA were included in the study (mean age: 64 ± 14 years, 62% men). Eighty‐eight patients had M1 MCA occlusions; baseline mean National Institutes of Health Stroke Scale (NIHSS) score was 16, and a 24‐hour mean NIHSS score was 10 points. An aMCA/cMCA MFV ratio of <.6 had a sensitivity of 99%, specificity of 16%, positive predictive value (PV) of 60%, and negative PV of 94% for identifying large vessel occlusion (LVO) including M1 MCA, terminal internal carotid artery, or tandem ICA/MCA. Thrombolysis in Brain Ischemia scale, with (grade ≥1) compared to without flow (grade 0), showed a sensitivity of 17.1%, specificity of 86.9%, positive PV of 62%, and negative PV of 46% for identifying LVO. Conclusions: TCD is a valuable modality for evaluating arterial circulation in acute ischemic stroke patients, demonstrating significant potential as a screening tool for intravenous/intra‐arterial lysis protocols. [ABSTRACT FROM AUTHOR]

Time constant of the cerebral arterial bed (τ) is a transcranial Doppler (TCD) based metric that is expected to quantify the transit time of red blood cells from the insonation point to the arteriole-capillary boundary during a cardiac cycle. This study aims to assess the potential of τ as an early predictor of delayed cerebral ischemia (DCI). Consecutive patients (56 ± 15 years) treated for aneurysmal subarachnoid haemorrhage were included in the study. τ was assessed through a modelling approach that involved simultaneous recordings of arterial blood pressure and cerebral blood flow velocity (CBFV) from TCD's first recordings. 71 patients were included. 17 patients experienced DCI. τ was significantly shorter in patients who later developed DCI: 187 ± 64 ms vs. 249 ± 184 ms; p = 0.040 with moderate effect size (rG = 0.24). Logistic regression showed that there was a significant association between increased CBFV, shortened τ, and the development of DCI (χ2 = 11.54; p = 0.003) with AUC for the model 0.75. Patients who had both shortened τ and increased CBFV were 20 times more likely to develop DCI (OR = 20.4 (2.2–187.7)). Our results suggest that early alterations in τ are associated with DCI after aSAH. The highest performance of the model including both CBFV and τ may suggest the importance of both macrovascular and microvascular changes assessment. [ABSTRACT FROM AUTHOR]

Background: Volitionally modifying respiration leads to changes in middle cerebral arterial (MCA) blood flow. The effect of changes in breath rate on MCA blood flow has not been reported. Aims and Objectives: To determine the effect of slow (bumblebee yoga breathing) and fast (high frequency yoga breathing) yoga breathing techniques on MCA blood flow and vagally mediated heart rate variability. Materials and Methods: Thirty participants (mean age ± standard deviation, 27.3 ± 4.2 years) were assessed on 2 separate days practicing either high frequency yoga breathing (HFYB, breath frequency 54.2/min) or slow frequency bumblebee yoga breathing (BBYB, breath frequency 3.8/min) in random order to determine the effects of changes in breath frequency on MCA hemodynamics. Assessments included transcranial Doppler sonography, vagally mediated heart rate variability (VmHRV), and respiration. Results: Both HFYB and BBYB (i) reduced MCA flow velocities, i.e., peak systolic, end diastolic, and mean flow velocities, and (ii) increased MCA pulsatility indices. There was an increase in VmHRV during BBYB based on increased power in high frequency (HF) and low frequency (LF). LF reflects VmHRV for slow breath frequencies. In BBYB the average breath rate was 3.8 breaths/min. In contrast, VmHRV decreased during HFYB (based on reduced HF power; repeated measures analysis of variance, P < 0.05, all cases). Conclusion: Hence, irrespective of the differences in breath frequency, both HFYB and BBYB appear to reduce MCA flow velocities and increase the resistance to blood flow bilaterally, although the VmHRV changed in opposite directions. MCA velocity and pulsatility changes are speculated to be associated with low global neural activity during yoga breathing.

Introduction: Encephalopathy, a common complication in Intensive Care Unit (ICU) patients, is often linked to poor outcomes. Transcranial Doppler (TCD), a non-invasive tool assesses cerebral perfusion via the Pulsatility Index (PI), Resistivity Index (RI), and Time-Averaged Peak (TAP) or Mean Flow Velocity (MFV). These parameters may offer insights into cerebral perfusion and outcomes in encephalopathic patients. Aim: To describe the PI, RI of the Middle Cerebral Artery (MCA), and MFV or TAP measured by TCD in patients admitted to the ICU, comparing those with and without encephalopathy at the time of admission. Materials And Methods: This cross-sectional observational study was conducted from January 2019 to November 2020, in a combined medical-surgical ICU of a tertiary care hospital, involving 45 enrolled patients. Patients were evaluated within 24 hours of admission and subsequently every 24 hours until ICU discharge, death, or discharge against medical advice. Bilateral Middle cerebral artery TCD studies were conducted using a 1-5 MHz phased array probe or TCD mode through the transtemporal window. The PI, RI, and MFV were measured on both sides, with the higher value used for analysis, and all statistical analyses were performed using Statistics and Data 13 software. Results: In the present study, 88% (n=40) of patients had encephalopathy (GCS

Abstract The mean flow index—usually referred to as Mx—has been used for assessing dynamic cerebral autoregulation (dCA) for almost 30 years. However, concerns have arisen regarding methodological consistency, construct and criterion validity, and test–retest reliability. Methodological nuances, such as choice of input (cerebral perfusion pressure, invasive or non‐invasive arterial pressure), pre‐processing approach and artefact handling, significantly influence mean flow index values, and previous studies correlating mean flow index with other established dCA metrics are confounded by inherent methodological flaws like heteroscedasticity, while the mean flow index also fails to discriminate individuals with presumed intact versus impaired dCA (discriminatory validity), and its prognostic performance (predictive validity) across various conditions remains inconsistent. The test–retest reliability, both within and between days, is generally poor. At present, no single approach for data collection or pre‐processing has proven superior for obtaining the mean flow index, and caution is advised in the further use of mean flow index‐based measures for assessing dCA, as current evidence does not support their clinical application.

Abstract Background Subarachnoid hemorrhage (SAH) patients with cerebral autoregulation (CA) impairment at an early post-SAH period are at high risk of unfavorable outcomes due to delayed cerebral ischemia (DCI) or other complications. Limited evidence exists for an association between early-stage CA impairments and SAH patient outcomes. The objective of this prospective study was to explore associations between CA impairments detected in early post-SAH snapshot examinations and patient outcomes. Methods The pilot observational study included 29 SAH patients whose CA status was estimated 2–3 days after spontaneous aneurysm rupture and a control group of 15 healthy volunteers for comparison. Inflatable leg recovery boots (reboots.com, Germany) were used for the safe controlled generation of arterial blood pressure (ABP) changes necessary for reliable CA examination. At least 5 inflation‒deflation cycles of leg recovery boots with a 2–3 min period were used during examinations. CA status was assessed according to the delay time (∆TCBFV) measured between ABP(t) and cerebral blood flow velocity (CBFV(t)) signals during artificially induced ABP changes at boot deflation cycle. CBFV was measured in middle cerebral artery by using transcranial Doppler device. Results Statistically significant differences in ∆TCBFV were found between SAH patients with unfavorable outcomes (∆TCBFV = 1.37 ± 1.23 s) and those with favorable outcomes (∆TCBFV = 2.86 ± 0.99 s) (p

Abstract Background Syncope is a common condition that increases the risk of injury and reduces the quality of life. Abdominal pain as a precursor to vasovagal syncope (VVS) in adults is rarely reported and is often misdiagnosed.​. Methods We present three adult patients with VVS and presyncopal abdominal pain diagnosed by synchronous multimodal detection (transcranial Doppler [TCD] with head-up tilt [HUT]) and discuss the relevant literature. Results Case 1: A 52-year-old man presented with recurrent decreased consciousness preceded by six months of abdominal pain. Physical examinations were unremarkable. Dynamic electrocardiography, echocardiography, head and neck computed tomography angiography, magnetic resonance imaging (MRI), and video electroencephalogram showed no abnormalities. Case 2: A 57-year-old woman presented with recurrent syncope for 30 + years, accompanied by abdominal pain. Physical examination, electroencephalography, and MRI showed no abnormalities. Echocardiography showed large right-to-left shunts. Case 3: A 30-year-old woman presented with recurrent syncope for 10 + years, with abdominal pain as a precursor. Physical examination, laboratory analysis, head computed tomography, electrocardiography, and echocardiography showed no abnormalities. Syncope secondary to abdominal pain was reproduced during HUT. Further, HUT revealed vasovagal syncope, and synchronous TCD showed decreased cerebral blood flow; the final diagnosis was VVS in all cases. Conclusions Abdominal pain may be a precursor of VVS in adults, and our findings enrich the clinical phenotypic spectrum of VVS. Prompt recognition of syncopal precursors is important to prevent incidents and assist in treatment decision-making. Abdominal pain in VVS may be a sign of sympathetic overdrive. Synchronous multimodal detection can help in diagnosing VVS and understanding hemodynamic mechanisms.

Background: Transcranial Doppler (TCD) is a technique to assess blood flow velocity in the cerebral arteries. TCD is frequently used to monitor aneurysmal subarachnoid hemorrhage (aSAH) patients. This study compares TCD-criteria for vasospasm and its association with Delayed Cerebral Ischemia (DCI). An overall score based on flow velocities of various intracranial arteries was developed and evaluated. Methods: A retrospective diagnostic accuracy study was conducted between 1998 and 2017 with 621 patients included. Mean flow velocity (MFV) of the cerebral artery was measured between 2–5 days and between 6–9 days after ictus. Cutoff values from the literature, new cutoff values, and a new composite score (Combined Severity Score) were used to predict DCI. Sensitivity, specificity, and area under the curve (AUC) were determined, and logistic regression analysis was performed. Results: The Combined Severity Score showed an AUC 0.64 (95%CI 0.56-.71) at days 2–5, with sensitivity 0.53 and specificity 0.74. The Combined Severity Score had an adjusted Odds Ratio of 3.41 (95CI 1.86–6.32) for DCI. MCA-measurements yielded the highest AUC to detect DCI at day 2–5: AUC 0.65 (95%CI 0.58–0.73). Optimal cutoff MFV of 83 cm/s for MCA resulted in sensitivity 0.73 and specificity 0.50 at days 2–5. Conclusion: TCD-monitoring of aSAH patients may be a valuable strategy for DCI risk stratification. Lower cutoff values can be used in the early phase after the ictus (day 2–5) than are commonly used now. The Combined Severity Score incorporating all major cerebral arteries may provide a meaningful contribution to interpreting TCD measurements. [ABSTRACT FROM AUTHOR]

Intracranial pressure (ICP) monitoring is necessary for managing patients with traumatic brain injury (TBI). Although gold-standard methods include intraventricular or intraparenchymal transducers, these systems cannot be used in patients with coagulopathies or in those who are at high risk of catheter-related infections, nor can they be used in resource-constrained settings. Therefore, a non-invasive modality that is more widely available, cost effective, and safe would have tremendous impact. Among such non-invasive choices, transcranial Doppler (TCD) provides indirect ICP estimates through waveform analysis of cerebral hemodynamic changes. The objective of this scoping review is to describe the existing evidence for the use of TCD-derived methods in estimating ICP in adult TBI patients as compared with gold-standard invasive methods. This review was conducted in accordance with the Joanna Briggs Institute methodology for scoping reviews, with a main search of PubMed and Embase. The search was limited to studies conducted in adult TBI patients published in any language between 2012 and 2022. Twenty-two studies were included for analysis, with most being prospective studies conducted in high-income countries. TCD-derived non-invasive ICP (nICP) methods are either mathematical or non-mathematical, with the former having slightly better correlation with invasive methods, especially when using time-trending ICP dynamics over one-time estimated values. Nevertheless, mathematical methods are associated with greater cost and complexity in their application. Formula-based methods showed promise in excluding elevated ICP, exhibiting a high negative predictive value. Therefore, TCD-derived methods could be useful in assessing ICP changes instead of absolute ICP values for high-risk patients, especially in low-resource settings. [ABSTRACT FROM AUTHOR]

Background: Transcranial Doppler (TCD) is a noninvasive bedside tool for cerebral hemodynamic assessments in multiple clinical scenarios. TCD, by means of measuring systolic and diastolic blood velocities, allows the calculation of the pulsatility index (PI), a parameter that is correlated with intracranial pressure (ICP). Nevertheless, the predictive value of the PI for raised ICP appears to be low, as it is subjected to several, often confounding, factors not related to ICP. Recently, the pulsatile apparent resistance (PaR) index was developed as a PI corrected for arterial blood pressure, reducing some of the confounding factors influencing PI. This study compares the predictive value of PaR versus PI for intracranial hypertension (IH) (ICP > 20 mm Hg) in patients with traumatic brain injury. Methods: Patients with traumatic brain injury admitted to the neurocritical care unit who required invasive ICP monitoring were included prospectively within 5 days of admission. TCD measurements were performed in both middle cerebral arteries, allowing calculations of the PI and PaR. The optimal cutoff, discriminative power of these parameters for ICP ≥ 20 mm Hg, was assessed by calculating the area under the receiver operator characteristics curve (AUC). Results: In total, 93 patients were included. A total of 20 (22%) patients experienced IH during the recording sessions. The discriminative power was low for PI (AUC 0.63) but slightly higher for PaR (AUC 0.77). Nonparametric analysis indicated significant difference for PaR when comparing patients with (median 0.169) and without IH (median − 0.052, p = 0.001), whereas PI medians for patients with and without IH were 0.86 and 0.77, respectively (p = 0.041). Regarding subanalyses, the discriminative power of these parameters increased after exclusion of patients who had undergone a neurosurgical procedure. This was especially true for the PaR (AUC 0.89) and PI (AUC 0.72). Among these patients, a PaR cutoff value of − 0.023 had 100% sensitivity and 52.9% specificity. Conclusions: In the present study, discriminative power of the PaR for discriminating IH was superior to the PI. The PaR seems to be a reliable noninvasive parameter for detecting IH. Further studies are warranted to define its clinical application, especially in aiding neurosurgical decision making, following up in intensive care units, and defining its ability to indicate responses according to the therapies administered. [ABSTRACT FROM AUTHOR]

Analyzing the value of quantitative transcranial doppler hemodynamic parameters in predicting prognosis in young stroke patients. Cases were included from April 2018 to December 2022, originating from the First Hospital of Qinhuangdao City, and the study population consisted of 349 young stroke patients, which were treated as a case group, according to disease, they were divided into mild, moderate and severe groups, with the numbers of cases being 97, 196, and 56, and according to the prognosis, they were divided into poor prognosis and good prognosis groups, with the numbers of cases being 27 and 322. 358 healthy young people as the control. The hemodynamic quantitative parameters were compared between the case and control group, patients with different severity of disease and different prognosis. The correlation and predictive value between hemodynamic quantitative parameters and the severity of disease and prognosis of patients were analyzed. Compared to the control, PI of middle cerebral artery in case group was higher, Vm, Vs, Vd, BHI and rCBFLI were lower (P<0.05). PI in the severe was higher than moderate and mild group (P<0.05), moderate was higher than mild group (P<0.05). Vm, Vs, Vd, BHI, rCBFLI of the severe were lower than moderate and mild group (P<0.05), moderate were lower than mild group (P<0.05). PI of MCA in the poor prognosis was higher than good prognosis group (P<0.05), BHI and rCBFLI of MCA in the poor prognosis were lower than good prognosis group (P<0.05). PI was positively correlated with the severity and prognosis of patients (P<0.05). Vm, Vs, Vd, BHI, rCBFLI of MCA were negatively correlated with the severity of patients (P<0.05). BHI and rCBFLI of middle cerebral artery were negatively correlated with the prognosis of patients (P<0.05). The AUC value of combined detection of PI, BHI and rCBFLI in predicting the prognosis of young stroke patients was 0.864, higher than PI, BHI and rCBFLI alone (0.698, 0.737, 0.782, P<0.05). The sensitivity of middle cerebral artery BHI and combined detection were 85.19% and 81.48% respectively, which were higher than that of middle cerebral artery PI and rCBFLI alone (66.67% and 62.96%, P<0.05). The specificity of rCBFLI and combined detection of MCA was 81.68% and 78.26% respectively, which was higher than that of PI and BHI alone (64.29% and 67.08%, P<0.05). PI was higher and Vm, Vs, Vd, BHI, rCBFLI were lower in young patients with stroke, and PI increased with the aggravation of the patient's condition, while Vm, Vs, Vd, BHI, rCBFLI decreased with the aggravation of the patient's condition. PI, BHI, rCBFLI could be used to evaluate the prognosis of the patients, and the combined detection of the three had higher predictive value. [ABSTRACT FROM AUTHOR]

Cerebral blood flow (CBF) autoregulation is the physiologic process whereby blood supply to the brain is kept constant over a range of cerebral perfusion pressures ensuring a constant supply of metabolic substrate. Clinical methods for monitoring CBF autoregulation were first developed for neurocritically ill patients and have been extended to surgical patients. These methods are based on measuring the relationship between cerebral perfusion pressure and surrogates of CBF or cerebral blood volume (CBV) at low frequencies (<0.05 Hz) of autoregulation using time or frequency domain analyses. Initially intracranial pressure monitoring or transcranial Doppler assessment of CBF velocity was utilised relative to changes in cerebral perfusion pressure or mean arterial pressure. A more clinically practical approach utilising filtered signals from near infrared spectroscopy monitors as an estimate of CBF has been validated. In contrast to the traditional teaching that 50 mm Hg is the autoregulation threshold, these investigations have found wide interindividual variability of the lower limit of autoregulation ranging from 40 to 90 mm Hg in adults and 20–55 mm Hg in children. Observational data have linked impaired CBF autoregulation metrics to adverse outcomes in patients with traumatic brain injury, ischaemic stroke, subarachnoid haemorrhage, intracerebral haemorrhage, and in surgical patients. CBF autoregulation monitoring has been described in both cardiac and noncardiac surgery. Data from a single-centre randomised study in adults found that targeting arterial pressure during cardiopulmonary bypass to above the lower limit of autoregulation led to a reduction of postoperative delirium and improved memory 1 month after surgery compared with usual care. Together, the growing body of evidence suggests that monitoring CBF autoregulation provides prognostic information on eventual patient outcomes and offers potential for therapeutic intervention. For surgical patients, personalised blood pressure management based on CBF autoregulation data holds promise as a strategy to improve patient neurocognitive outcomes. [ABSTRACT FROM AUTHOR]

The treatment of acute ischemic stroke has improved in last few decades. While meta-analyses of several trials have established the safety and efficacy of Intravenous (IV) Tenecteplase thrombolysis, concomitant continuous transcranial doppler (TCD) ultrasound administration has not been assessed in any clinical trial. The aim of this study was to determine the effects of continuous 2 MHz TCD ultrasound during IV Tenecteplase thrombolysis for Middle cerebral artery (MCA) stroke. A total of 19 patients were included, 13 received TCD ultrasound and 6 sham TCD with IV Tenecteplase. TCD spectrum and difference in Pre and post TCD parameters were measured. Asymptomatic hemorrhagic transformation of infarct was seen in two patients. There was no mortality or clinical worsening in the sonothrombolysis group as against sham sonothrombolysis group. Median of peak systolic velocity was increased in both the sonothrombolysis (P = 0.0002) and sham sonothrombolysis group (P-value = 0.001). The difference in change in mean flow velocity between two groups, sonothrombolysis (11 cm/sec) and sham sonothrombolysis (3.5 cm/sec) were also significantly different (P = 0.014). This pilot work has established safety of continuous 30 min TCD application along with IV Tenecteplase thrombolysis and it concludes that concomitant 2 MHz TCD ultrasound administration significantly increased the MCA blood flow compared to chemothrombolysis alone. CTRI Registered Number: CTRI/2021/02/031418. Highlights: The study demonstrates that chemothrombolysis with Tenecteplase in anterior circulation ischemic strokes augments cerebral blood flow velocity evident from TCD spectral parameters of peak systolic velocity and mean flow velocity. Further it showed when IV thrombolysis is combined with continuous 30 min transcranial ultrasound, the increase in cerebral blood flow is significantly augmented, suggesting an independent effect of simultaneous ultrasound exposure. The combination of continuous TCD with IV Tenecteplase did not enhance the hemorrhagic complications or mortality confirming the safety of the procedure in acute ischemic stroke. Whether the mechanism of augmentation of flow velocities is due to clot lysis or acceleration of fluid movement due to ultrasound energised fluid particles remains yet to be determined, but it has beneficial effects without compromising safety. [ABSTRACT FROM AUTHOR]

Background and Purpose: Thresholds for abnormal transcranial Doppler cerebrovascular reactivity (CVR) studies are poorly understood, especially for patients with cerebrovascular disease. Using a real‐world cohort with cerebral arterial stenosis, we sought to describe a clinically significant threshold for carbon dioxide reactivity (CO2R) and vasomotor range (VMR). Methods: CVR studies were performed during conditions of breathing room air normally, breathing 8% carbon dioxide air mixture, and hyperventilation. The mean and standard deviation (SD) of CO2R and VMR were calculated for the unaffected side in patients with unilateral stenosis; a deviation of 2 SDs below the mean was chosen as the threshold for abnormal. Receiver operating characteristic (ROC) curves for both sides for patients with unilateral and bilateral stenosis were evaluated for sensitivity (Sn) and specificity (Sp). Results: A total of 133 consecutive CVR studies were performed on 62 patients with stenosis with mean±SD age 55±16 years. Comorbidities included hypertension (60%), diabetes (15%), stroke (40%), and smoking (35%). In patients with unilateral stenosis, mean±SD CO2R for the unaffected side was 1.86±0.53%, defining abnormal CO2R as <0.80%. Mean±SD CO2R for the affected side was 1.27±0.90%. The CO2R threshold predicted abnormal acetazolamide single‐photon emission computed tomography (SPECT) (Sn =.73, Sp =.79), CT/MRI perfusion abnormality (Sn =.42, Sp =.77), infarction on MRI (Sn =.45, Sp =.76), and pressure‐dependent exam (Sn =.50, Sp =.76). For the unaffected side, mean±SD VMR was 39.5±15.8%, defining abnormal VMR as <7.9%. For the affected side, mean±SD VMR was 26.5±17.8%. The VMR threshold predicted abnormal acetazolamide SPECT (Sn =.46, Sp =.94), infarction on MRI (Sn =.27, Sp =.94), and pressure‐dependent exam (Sn =.31, Sp =.90). Conclusions: In patients with multiple vascular risk factors, a reasonable threshold for clinically significant abnormal CO2R is <0.80% and VMR is <7.9%. Noninvasive CVR may aid in diagnosing and risk stratifying patients with stenosis. [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]

Introduction: Encephalopathy, a common complication in Intensive Care Unit (ICU) patients, is often linked to poor outcomes. Transcranial Doppler (TCD), a non-invasive tool assesses cerebral perfusion via the Pulsatility Index (PI), Resistivity Index (RI), and Time-Averaged Peak (TAP) or Mean Flow Velocity (MFV). These parameters may offer insights into cerebral perfusion and outcomes in encephalopathic patients. Aim: To describe the PI, RI of the Middle Cerebral Artery (MCA), and MFV or TAP measured by TCD in patients admitted to the ICU, comparing those with and without encephalopathy at the time of admission. Materials and Methods: This cross-sectional observational study was conducted from January 2019 to November 2020, in a combined medical-surgical ICU of a tertiary care hospital, involving 45 enrolled patients. Patients were evaluated within 24 hours of admission and subsequently every 24 hours until ICU discharge, death, or discharge against medical advice. Bilateral Middle cerebral artery TCD studies were conducted using a 1-5 MHz phased array probe or TCD mode through the transtemporal window. The PI, RI, and MFV were measured on both sides, with the higher value used for analysis, and all statistical analyses were performed using Statistics and Data 13 software. Results: In the present study, 88% (n=40) of patients had encephalopathy (GCS<15 and RAAS less than or more than 0). The mean APACHE II score was 19 (14-25), indicating severe illness with a predicted mortality of 30-40%. Patients with encephalopathy had significantly higher APACHE II scores compared to those without (19.5 (16-25) vs 10 (4-19)). Although there was a trend towards a higher Pulsatility Index in encephalopathic patients at admission (1.11±0.378 vs 1.07±0.12, p=0.81), PI, RI, and TAP values did not significantly differ in non-survivors (1.12±0.49 vs 1.11±0.33, p=0.750). Persistent encephalopathy was associated with a trend towards higher PI at admission (1.05±0.24 vs 1.16±0.46; p=0.756), and a moderate correlation was found between decreasing PI and improvement in GCS (rho=-0.489, p=0.001). Conclusions: PI, RI, and TAP at the time of admission were not found to be associated with occurrence and recovery of encephalopathy as well as mortality. The trend of change in PI moderately correlated with improvement in GCS suggesting the importance of trends rather than absolute values. [ABSTRACT FROM AUTHOR]

Neurovascular coupling (NVC) represents the increase in regional blood flow associated with neural activity. The aim here was to describe a new approach to non-invasive measurement of NVC by spectral analysis of the cerebral blood flow velocity (CBFV) with transcranial Doppler. In a sample of 20 healthy participants, we monitored systolic CBFV in the left posterior cerebral artery (PCA) during off (eyes closed) and on (flickering checkerboard) periods. The contralateral middle cerebral artery was simultaneously monitored as a control. Each participant was submitted to three experiments, each having five cycles, with increasing duration of the cycles, from 10 s (0.1 Hz) to 20 s (0.05 Hz) and lastly 40 s (0.025 Hz), half the time for on and for off periods, constituting a total of 6 min. The successive cycles were expected to cause oscillation in CBFV in a sinusoidal pattern that could be characterized by spectral analysis. We also measured the classic CBFV overshoot as the relative increase in percentage of systolic CBFV from baseline. The relationship and agreement between the two methods were analyzed by linear regression and Bland–Altman plots. In every participant, a clear peak of amplitude in the PCA CBFV spectrum was discernible at 0.1, 0.05 and 0.025 Hz of visual stimulation. On average, this amplitude was 7.1 ± 2.3%, 10.9 ± 3.5% and 17.3 ± 6.5%, respectively. This response contrasted significantly with an absent peak in middle cerebral artery monitoring (p < 0.0001). The spectral amplitude and classic overshoot were highly correlated and linearly related (p < 0.0001). NVC can be quantified by the spectral amplitude of PCA CBFV at slower and higher frequencies of visual stimulation. This method represents an alternative to classic overshoot without the need for stimulus marking or synchronization. [ABSTRACT FROM AUTHOR]

Objective Transcranial Doppler (TCD) and brain MRI may be useful in evaluating patients with APS, helping to stratify the risk of cerebrovascular ischaemic events in this population. This study aimed to assess the frequency of brain MRI abnormalities in patients with primary antiphospholipid syndrome, secondary antiphospholipid syndrome and SLE and correlate to TCD findings. Methods The study, conducted over four years at two autoimmune disease referral centres, included 22 primary antiphospholipid syndrome patients, 24 secondary antiphospholipid syndrome patients, 27 SLE patients without APS and 21 healthy controls. All participants underwent TCD to assess cerebral haemodynamics, detect microembolic signals and evaluate right-to-left shunts, followed by brain MRI and magnetic resonance angiography. MRI scans were reviewed for acute microembolism, localized cortical infarctions, border infarctions, lacunar infarctions, ischaemic lesions, white matter hyperintensity, micro and macro haemorrhages and arterial stenosis ≥50% of the cervical carotid artery, by two neuroradiologists blinded to the clinical data. Results Brain MRI findings were similar between the groups, except for lacunar infarction, more frequent in patients with secondary antiphospholipid syndrome (P  = 0.022). Patients with intracranial stenosis detected by TCD had a higher frequency of territorial infarction (40% vs 7.5%, P  = 0.02), lacunar (40% vs 11.3%, P  = 0.075) and border zone infarcts (20% vs 1.9%, P  = 0.034). Conclusions Patients with intracranial stenosis presented a higher frequency of territorial, lacunar and border zone infarcts, suggesting that evaluating the intracranial vasculature should not be neglected in patients with APS and stroke. [ABSTRACT FROM AUTHOR]

Transcranial Doppler (TCD) is a repeatable, at‐the‐bedside, helpful tool for confirming cerebral circulatory arrest (CCA). Despite its variable accuracy, TCD is increasingly used during brain death determination, and it is considered among the optional ancillary tests in several countries. Among its limitations, the need for skilled operators with appropriate knowledge of typical CCA patterns and the lack of adequate acoustic bone windows for intracranial arteries assessment are critical. The purpose of this review is to describe how to evaluate cerebral circulatory arrest in the intensive care unit with TCD and transcranial duplex color‐coded doppler (TCCD). [ABSTRACT FROM AUTHOR]

Background: Subarachnoid hemorrhage (SAH) patients with cerebral autoregulation (CA) impairment at an early post-SAH period are at high risk of unfavorable outcomes due to delayed cerebral ischemia (DCI) or other complications. Limited evidence exists for an association between early-stage CA impairments and SAH patient outcomes. The objective of this prospective study was to explore associations between CA impairments detected in early post-SAH snapshot examinations and patient outcomes. Methods: The pilot observational study included 29 SAH patients whose CA status was estimated 2–3 days after spontaneous aneurysm rupture and a control group of 15 healthy volunteers for comparison. Inflatable leg recovery boots (reboots.com, Germany) were used for the safe controlled generation of arterial blood pressure (ABP) changes necessary for reliable CA examination. At least 5 inflation‒deflation cycles of leg recovery boots with a 2–3 min period were used during examinations. CA status was assessed according to the delay time (∆TCBFV) measured between ABP(t) and cerebral blood flow velocity (CBFV(t)) signals during artificially induced ABP changes at boot deflation cycle. CBFV was measured in middle cerebral artery by using transcranial Doppler device. Results: Statistically significant differences in ∆TCBFV were found between SAH patients with unfavorable outcomes (∆TCBFV = 1.37 ± 1.23 s) and those with favorable outcomes (∆TCBFV = 2.86 ± 0.99 s) (p < 0.001). Early assessment of baroreflex sensitivity (BRS) during the deflation cycle showed statistically significant differences between the DCI and non-DCI patient groups (p = 0.039). Conclusions: A relatively small delay of ∆TCBFV <1.6 s between CBFV(t) and ABP(t) waves could be an early warning sign associated with unfavorable outcomes in SAH patients. The BRS during boot deflation can be used as a biomarker for the prediction of DCI. Trial registration: ClinicalTrials.gov Identifier: NCT06028906. Registered 31 August 2023 - Retrospectively registered, https://www.clinicaltrials.gov/study/NCT06028906. [ABSTRACT FROM AUTHOR]

Background: Syncope is a common condition that increases the risk of injury and reduces the quality of life. Abdominal pain as a precursor to vasovagal syncope (VVS) in adults is rarely reported and is often misdiagnosed.​. Methods: We present three adult patients with VVS and presyncopal abdominal pain diagnosed by synchronous multimodal detection (transcranial Doppler [TCD] with head-up tilt [HUT]) and discuss the relevant literature. Results: Case 1: A 52-year-old man presented with recurrent decreased consciousness preceded by six months of abdominal pain. Physical examinations were unremarkable. Dynamic electrocardiography, echocardiography, head and neck computed tomography angiography, magnetic resonance imaging (MRI), and video electroencephalogram showed no abnormalities. Case 2: A 57-year-old woman presented with recurrent syncope for 30 + years, accompanied by abdominal pain. Physical examination, electroencephalography, and MRI showed no abnormalities. Echocardiography showed large right-to-left shunts. Case 3: A 30-year-old woman presented with recurrent syncope for 10 + years, with abdominal pain as a precursor. Physical examination, laboratory analysis, head computed tomography, electrocardiography, and echocardiography showed no abnormalities. Syncope secondary to abdominal pain was reproduced during HUT. Further, HUT revealed vasovagal syncope, and synchronous TCD showed decreased cerebral blood flow; the final diagnosis was VVS in all cases. Conclusions: Abdominal pain may be a precursor of VVS in adults, and our findings enrich the clinical phenotypic spectrum of VVS. Prompt recognition of syncopal precursors is important to prevent incidents and assist in treatment decision-making. Abdominal pain in VVS may be a sign of sympathetic overdrive. Synchronous multimodal detection can help in diagnosing VVS and understanding hemodynamic mechanisms. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The mean flow index—usually referred to as Mx—has been used for assessing dynamic cerebral autoregulation (dCA) for almost 30 years. However, concerns have arisen regarding methodological consistency, construct and criterion validity, and test–retest reliability. Methodological nuances, such as choice of input (cerebral perfusion pressure, invasive or non‐invasive arterial pressure), pre‐processing approach and artefact handling, significantly influence mean flow index values, and previous studies correlating mean flow index with other established dCA metrics are confounded by inherent methodological flaws like heteroscedasticity, while the mean flow index also fails to discriminate individuals with presumed intact versus impaired dCA (discriminatory validity), and its prognostic performance (predictive validity) across various conditions remains inconsistent. The test–retest reliability, both within and between days, is generally poor. At present, no single approach for data collection or pre‐processing has proven superior for obtaining the mean flow index, and caution is advised in the further use of mean flow index‐based measures for assessing dCA, as current evidence does not support their clinical application. What is the topic of this review?The validity and reliability of mean flow index‐based measures for assessing dynamic cerebral autoregulation (dCA) in humans.What advances does it highlight?Current evidence does not support the clinical application of mean flow index‐based measures, warranting caution in their further use for dCA assessment. [ABSTRACT FROM AUTHOR]

Background This study aimed to clarify the characteristics and survival prediction value of transcranial Doppler microembolic signals (MES) in patients with acute cerebral infarction and active cancer. Methods and Results Between 2017 and 2022, 1089 cases of acute cerebral infarction were recorded within 7 days of disease onset. Among them, transcranial Doppler was successful in 33 patients who had active cancer, and these data were analyzed in this study. The primary outcomes were stroke recurrence and mortality at 3 months. The study population had the following characteristics [median (interquartile range)]: age, 70 years (63–78); body mass index, 21.6 (20–24), National Institutes of Health Stroke Scale 3 (1–6), and modified Rankin Scale score at discharge 1 (1–4). The most common cancer types were lung (24%), pancreatic (24%), and intestinal (18%). MES was present in 16 of 33 patients (48.5%). The presence and number of MES were significantly associated with the levels of D‐dimer (P

Background: Orthostatic intolerance (OI) is the inability to tolerate orthostatic stress during any postural change. The etiology of OI varies, and methods to obtain a specific diagnosis and plan appropriate treatment are important. The tools available within the Chinese context to swiftly identify orthostatic intolerance syndrome (OIS) are currently limited. Methods: Patients with OI symptoms were included in this study and categorized into two groups based on the results of the supine-to-stand test. Those with abnormal test results were assigned to the OIS group, while those with normal test results were placed in the non-OIS group. We evaluated the internal consistency and predictive value of the Chinese Orthostatic Discriminant and Severity Scale (ODSS) by comparing patients’ scores with their physiological measurements collected during orthostatic stress tests and the results of other available questionnaires, including the orthostatic Symptom Questionnaire and Orthostatic Grading Scale (OGS). Results: Patients with OIS scored significantly higher on all three questionnaires and showed significant differences in autonomic responses during orthostatic stress tests compared with non-OIS patients. Receiver operating characteristic curve analysis showed that the orthostatic score from the ODSS had moderate predictive value for the supine test (area under the curve [AUC] = 0.754). Further subgroup analysis revealed that the orthostatic score from the ODSS had uniquely high specificity and sensitivity for identifying patients with orthostatic hypotension with abnormal cerebral blood flow (OH–U, AUC = 0.919). Conclusions: We conclude that the Chinese version of the ODSS has sufficient reliability and validity to distinguish patients with OIS and could possibly be used as a diagnostic tool for OH–U patients. Thus, the Chinese ODSS offers a beneficial screening tool for quickly assessing whether patients have OIS that requires further clinical assessment.

IntroductionConcerns 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.MethodsWe investigated MCAv using transcranial Doppler in 0° head position, then at 30°, 70°, 90° sitting, and 90° standing, at

超声由于其独特的优势已逐渐应用于脑小血管病领域。本文汇总了超声在脑小血管病中应用的相关研究，概述了脑小血管病与血管超声各类评估指标之间的关系，并描述了超声在与脑小血管病并存的心、脑、肾等多系统疾病中的评估、诊断作用，为应用超声对脑小血管病进行全面有效评估提供了理论依据。 Abstract: Ultrasound has been gradually applied to the field of cerebral small vessel disease (CSVD) due to its unique advantages. This paper summarized the studies related to ultrasound in CSVD, and summarized the relationship between CSVD and various evaluation indicators of vascular ultrasound. What’s more, this paper described the role of ultrasound in the evaluation and diagnosis of multi-system diseases such as heart, brain, and kidney coexisting with CSVD, and provided a theoretical basis for comprehensive and effective evaluation of CSVD by ultrasound.

Abstract Background During cardiac surgery, transcranial Doppler (TCD) represents a non-invasive modality that allows measurement of red blood cell flow velocities in the cerebral arteries. TCD can also be used to detect and monitor embolic material in the cerebral circulation. Detection of microemboli is reported as a high intensity transient signal (HITS). The importance of cerebral microemboli during cardiac surgery has been linked to the increased incidence of postoperative renal failure, right ventricular dysfunction, and hemodynamic instability. The objective of this study is to determine whether the embolic load is associated with hemodynamic instability during cardiopulmonary bypass (CPB) separation and postoperative complications. Methods A retrospective single-centre cohort study of 354 patients undergoing cardiac surgery between December 2015 and March 2020 was conducted. Patients were divided in tertiles, where 117 patients had a low quantity of embolic material (LEM), 119 patients have a medium quantity of microemboli (MEM) and 118 patients who have a high quantity of embolic material (HEM). The primary endpoint was a difficult CPB separation. Multivariate logistic regression was used to determine the potential association between a difficult CPB separation and the number of embolic materials. Results Patients who had a difficult CPB separation had more HITS compared to patients who had a successful CPB separation (p

Abstract Background Children with sickle cell anemia (SCA) are at high risk for stroke. Protocols for stroke prevention including blood transfusions, screening for abnormal non-imaging transcranial Doppler (TCD) measurements, and hydroxyurea therapy are difficult to implement in low-resource environments like Nigeria. This study aimed to examine the contextual factors around TCD screening in a community hospital in Nigeria using qualitative interviews and focus groups. Methods We conducted a descriptive qualitative study in a community hospital in Kaduna, Nigeria, using focus groups and interviews. Interview guides and analysis were informed by the Consolidated Framework for Implementation Research (CFIR) framework and the Theory of Planned Behavior. Transcripts were coded and analyzed using an iterative deductive (CFIR)/Inductive (transcribed quotes) qualitative methodology. Results We conducted two focus groups and five interviews with health care workers (nurses and doctors) and hospital administrators, respectively. Themes identified key elements of the inner setting (clinic characteristics, resource availability, implementation climate, and tension for change), characteristics of individuals (normative, control, and behavioral beliefs), and the implementation process (engage, implement, and adopt), as well as factors that were influenced by external context, caregiver needs, team function, and intervention characteristics. Task shifting, which is already being used, was viewed by providers and administrators as a necessary strategy to implement TCD screening in a clinic environment that is overstressed and under-resourced, a community stressed by poverty, and a nation with an underperforming health system. Conclusion Task shifting provides a viable option to improve health care by making more efficient use of already available human resources while rapidly expanding the human resource pool and building capacity for TCD screening of children with SCD that is more sustainable. Trial registration NCT05434000.

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]

Point-of-care brain ultrasound and transcranial doppler or color-coded doppler is being increasingly used as an essential diagnostic and monitoring tool at the bedside of critically ill neonates and children. Brain ultrasound has already established as a cornerstone of daily practice in the management of the critically ill newborn for diagnosis and follow-up of the most common brain diseases, considering the easiness to insonate the brain through transfontanellar window. In critically ill children, doppler based techniques are used to assess cerebral hemodynamics in acute brain injury and recommended for screening patients suffering from sickle cell disease at risk for stroke. However, more evidence is needed regarding the accuracy of doppler based techniques for non-invasive estimation of cerebral perfusion pressure and intracranial pressure, as well as regarding the accuracy of brain ultrasound for diagnosis and monitoring of acute brain parenchyma alterations in children. This review is aimed at providing a comprehensive overview for clinicians of the technical, anatomical, and physiological basics for brain ultrasonography and transcranial doppler or color-coded doppler, and of the current status and future perspectives of their clinical applications in critically ill neonates and children. Conclusion: In critically ill neonates, brain ultrasound for diagnosis and follow-up of the most common cerebral pathologies of the neonatal period may be considered the standard of care. Data are needed about the possible role of doppler techniques for the assessment of cerebral perfusion and vasoreactivity of the critically ill neonate with open fontanelles. In pediatric critical care, doppler based techniques should be routinely adopted to assess and monitor cerebral hemodynamics. New technologies and more evidence are needed to improve the accuracy of brain ultrasound for the assessment of brain parenchyma of critically ill children with fibrous fontanelles. What is Known: • In critically ill neonates, brain ultrasound for early diagnosis and follow-up of the most common cerebral and neurovascular pathologies of the neonatal period is a cornerstone of daily practice. In critically ill children, doppler-based techniques are more routinely used to assess cerebral hemodynamics and autoregulation after acute brain injury and to screen patients at risk for vasospasm or stroke (e.g., sickle cell diseases, right-to-left shunts). What is New: • In critically ill neonates, research is currently focusing on the use of novel high frequency probes, even higher than 10 MHz, especially for extremely preterm babies. Furthermore, data are needed about the role of doppler based techniques for the assessment of cerebral perfusion and vasoreactivity of the critically ill neonate with open fontanelles, also integrated with a non-invasive assessment of brain oxygenation. In pediatric critical care, new technologies should be developed to improve the accuracy of brain ultrasound for the assessment of brain parenchyma of critically ill children with fibrous fontanelles. Furthermore, large multicenter studies are needed to clarify role and accuracy of doppler-based techniques to assess cerebral perfusion pressure and its changes after treatment interventions. [ABSTRACT FROM AUTHOR]

Objective: To discuss the association between hemodynamic patterns and the risk of ischemic stroke in the people with chronic orthostatic intolerance (OI), and to provide the basis for the early assessment of the onset of ischemic stroke. Methods: A total of 638 residents aged ≥40 years from three streets/townships in Changchun City of Jilin Province were selected as the subjects by multistage random sampling method. Transcranial Doppler (TCD) combined with head-up tilt test (HUTT) were used to evaluate the hemodynamic patterns of the people with OI, and the OI research cohort was established. The patients were divided into orthostatic hypotension (OH) group, orthostatic hypertension (OHT) group, postural tachycardia syndrome (POTS) group, and orthostatic cerebral hypoperfusion syndrome (OCHOs) group according to the changes of hemodynamics. The subjects were followed up once every six months for two years, and the first incidence of ischemic stroke of the subjects was regarded as the observation endpoint; the baseline data and incidence of ischemic stroke of the subjects during the follow-up period were collected; Cox proportional hazards model was used to analyze the association factors with the risk of ischemic stroke. Results: A total of 121 subjects were diagnosed with OI, including 80 subjects (66.12%) in OH group, 35 subjects (28.93%) in OHT group, 5 (4.13%) subjects in POTS group, and 1 subject (0.82%) in OCHOs group. During the follow-up period, the overall people had 43 confirmed new cases of ischemic stroke. After controlling the related confounding factors, compared with non-OI individuals, the risk of ischemic stroke in the entire OI people, as well as in the OH and OHT patients, was increased by 1.527 times [hazard ratio (HR) =2.527, 95% confidence interval (CI) : 1.269－5.032, P<0.01)], 2.268 times (HR=3.268, 95% CI: 1.603－6.663, P=0.001), and 2.153 times (HR=3.153, 95% CI: 1.213－8.916, P=0.008), respectively. Conclusion: OI is associated with the increased risk of ischemic stroke, particularly in the patients in OH and OHT groups. [ABSTRACT FROM AUTHOR]

BACKGROUND: Strokes are the most common cause of death and the leading cause of acquired disability in adults worldwide. OBJECTIVE: The present study aimed to investigate the value of transcranial Doppler ultrasound (TCD) in the diagnosis of intracranial vascular stenosis in patients with a history of stroke. METHODS: This is a meta-analysis study of diagnostic tests. PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure, Wanfang, and VIP databases were systematically searched. Diagnostic tests using TCD or transcranial colour Doppler ultrasound (TCCD) for detecting intracranial arterial stenosis in patients with a history of stroke were included, with reference standards of intracranial angiography, computed tomography angiography (CTA), or magnetic resonance angiography. The risk bias map was drawn by Revman v5.3, the sensitivity and specificity forest plot was drawn by Stata v16.0, the receiver operating characteristic curve was drawn, and the area under the curve (AUC) was calculated. RESULTS: A total of 812 patients with stroke in 12 studies were included in the meta-analysis. The estimated sensitivity of TCD or TCCD for the detection of intracranial vascular stenosis was 0.77–1.00, and the combined sensitivity was 0.96 (95% confidence interval [CI]: 0.88–0.99); the estimated specificity was 0.32–1.00, and the combined specificity was 0.94 (95% CI: 0.82–0.98); the positive likelihood ratio was 15.8 (95% CI: 5.1–48.6); and the negative likelihood ratio was 0.04 (95% CI: 0.01–0.14). The AUC was 0.99 (95% CI: 0.97–0.99). CONCLUSION: Doppler ultrasound has good consistency with conventional methods for the diagnosis of intracranial artery stenosis in patients with a history of stroke. Different reference standards may affect sensitivity and specificity; when CTA was used as the reference standard, the consistency of the TCD in the diagnosis of intracranial artery stenosis in stroke patients was relatively good. [ABSTRACT FROM AUTHOR]

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Background: During cardiac surgery, transcranial Doppler (TCD) represents a non-invasive modality that allows measurement of red blood cell flow velocities in the cerebral arteries. TCD can also be used to detect and monitor embolic material in the cerebral circulation. Detection of microemboli is reported as a high intensity transient signal (HITS). The importance of cerebral microemboli during cardiac surgery has been linked to the increased incidence of postoperative renal failure, right ventricular dysfunction, and hemodynamic instability. The objective of this study is to determine whether the embolic load is associated with hemodynamic instability during cardiopulmonary bypass (CPB) separation and postoperative complications. Methods: A retrospective single-centre cohort study of 354 patients undergoing cardiac surgery between December 2015 and March 2020 was conducted. Patients were divided in tertiles, where 117 patients had a low quantity of embolic material (LEM), 119 patients have a medium quantity of microemboli (MEM) and 118 patients who have a high quantity of embolic material (HEM). The primary endpoint was a difficult CPB separation. Multivariate logistic regression was used to determine the potential association between a difficult CPB separation and the number of embolic materials. Results: Patients who had a difficult CPB separation had more HITS compared to patients who had a successful CPB separation (p < 0.001). In the multivariate analysis, patients with MEM decreased their odds of having a difficult CPB weaning compared to patients in the HEM group (OR = 0.253, CI 0.111–0.593; p = 0.001). In the postoperative period patients in the HEM group have a higher Time of Persistent Organ Dysfunction (TPOD), a longer stay in the ICU, a longer duration under vasopressor drugs and a higher mortality rate compared to those in the MEM and LEM groups. Conclusion: The result of this study suggests that a high quantity of cerebral embolic material increases the odds of having a difficult CPB separation. Also, it seems to be associated to more complex surgery, a longer CPB time, a higher TPOD and a longer stay in the ICU. Six out of eight patients who died in this cohort were in the HEM group. [ABSTRACT FROM AUTHOR]

Traumatic brain injury remains a major cause of mortality and morbidity in children across the world. Current management based on international guidelines focuses on a fixed therapeutic target of less than 20 mm Hg for managing intracranial pressure and 40–50 mm Hg for cerebral perfusion pressure across the pediatric age group. To improve outcome from this complex disease, it is essential to understand the pathophysiological mechanisms responsible for disease evolution by using different monitoring tools. In this narrative review, we discuss the neuromonitoring tools available for use to help guide management of severe traumatic brain injury in children and some of the techniques that can in future help with individualizing treatment targets based on advanced cerebral physiology monitoring. [ABSTRACT FROM AUTHOR]

Children with moyamoya are at high risk for incident and recurrent stroke. Transcranial Doppler (TCD) ultrasound is an attractive option to screen high-risk populations for moyamoya and to provide stroke risk stratification information due to its safety and cost-effectiveness. We used TCD to evaluate cerebral blood flow velocities in children with presurgical moyamoya and to determine if velocities differ between children with stable and unstable disease. Fourteen participants aged ≤21 years with a radiographic diagnosis of moyamoya or moyamoya-like arteriopathy underwent a research TCD at a median age of 7.2 years. TCDs were performed outside of the setting of acute stroke and before surgical revascularization. Arteriopathy was classified as unstable if the participant had a stroke or transient ischemic attack within three months preceding the TCD. Middle cerebral artery and internal carotid artery (ICA) blood flow velocities were elevated. The median M1 velocity was 138 cm/s (interquartile range [IQR] 106 to 168). Individual M1 flow velocities were a median of 5.0 S.D.s above age-based normative values. The median distal ICA velocity was 146 cm/s (IQR 124 to 163). Individual ICA flow velocities were a median of 5.9 S.D.s above normative values. Participants with unstable arteriopathy had higher M1 velocities compared with those with stable arteriopathy (170 vs 119 cm/s, P = 0.0003). We did not identify velocity differences based on comorbid conditions or age. These preliminary data suggest that TCD is a promising tool for screening for cerebral arteriopathies in high-risk pediatric populations and assessment for unstable disease. [ABSTRACT FROM AUTHOR]

Aims: Most studies focus on dynamic cerebral autoregulation (dCA) in the middle cerebral artery (MCA), and few studies investigated neurovascular coupling (NVC) and dCA in the posterior cerebral artery (PCA). We investigated NVC and dCA of the PCA in healthy volunteers to identify sex differences. Methods: Thirty men and 30 age‐matched women completed dCA and NCV assessments. The cerebral blood flow velocity (CBFV) and mean arterial pressure were evaluated using transcranial Doppler ultrasound and a servo‐controlled plethysmograph, respectively. The dCA parameters were analyzed using transfer function analysis. The NCV was evaluated by eyes‐open and eyes‐closed (24 s each) periodically based on voice prompts. The eyes‐open visual stimulation comprised silent reading of Beijing‐related tourist information. Results: The PCA gain was lower than that of the MCA in all frequency ranges (all p < 0.05). Phase was consistent across the cerebrovascular territories. The cerebrovascular conductance index (CVCi) and mean CBFV (MV) of the PCA were significantly higher during the eyes‐open than eyes‐closed period (CVCi: 0.50 ± 0.12 vs. 0.38 ± 0.10; MV: 42.89 ± 8.49 vs. 32.98 ± 7.25, both p < 0.001). The PCA dCA and NVC were similar between the sexes. Conclusion: We assessed two major mechanisms that maintain cerebral hemodynamic stability in healthy men and women. The visual stimulation‐evoked CBFV of the PCA was significantly increased compared to that during rest, confirming the activation of NVC. Men and women have similar functions in PCA dCA and NCV. [ABSTRACT FROM AUTHOR]

The central and peripheral nervous systems are the primary target organs during anaesthesia. At the time of the inception of the British Journal of Anaesthesia , monitoring of the central nervous system comprised clinical observation, which provided only limited information. During the 100 yr since then, and particularly in the past few decades, significant progress has been made, providing anaesthetists with tools to obtain real-time assessments of cerebral neurophysiology during surgical procedures. In this narrative review article, we discuss the rationale and uses of electroencephalography, evoked potentials, near-infrared spectroscopy, and transcranial Doppler ultrasonography for intraoperative monitoring of the central and peripheral nervous systems. [ABSTRACT FROM AUTHOR]

Purpose: Aneurysmal subarachnoid hemorrhage (aSAH) is associated with high morbidity and mortality, which is largely attributable to secondary complications such as vasospasm and subsequent delayed cerebral ischemia. Transcranial Doppler (TCD) is recommended for the screening of vasospasm; however, technicians are not always available. We aimed to see how feasible and reliable bedside transcranial point‐of‐care ultrasound (POCUS) color‐coded duplex sonography was compared with formal non‐imaging TCD in measuring velocities and in diagnosing vasospasm. Methods: This was a prospective observational study that took place in the neuroscience intensive care unit at a single academic medical center. Patients with aSAH who were undergoing formal TCDs were scanned on days 2–10 of their admission by physicians of ranging ultrasound experience. Absolute velocities were compared as well as the diagnosis of vasospasm via POCUS and formal TCDs. Results: A total of 226 bedside ultrasound exams were performed and compared with 126 formal TCD studies. Sonographic windows were obtained in 89.4% of patients. Scans took 6.6 minutes to complete on average by the advanced group versus 14.5 minutes in the beginner. Correlation ranged from.52 in the beginner group to.65 in the advanced. When good quality of images obtained at a depth of 4–5 cm were reviewed, correlation of mean velocities increased to.96. Overall sensitivity for diagnosing vasospasm was 75%, with a specificity of 99% and negative predictive value of 99%. Conclusion: Overall, POCUS TCD cannot replace a formal study performed by expert sonographers. An abbreviated POCUS scan can be performed quickly, however, particularly with more experienced operators. POCUS TCD can also feasibly detect vasospasm, and accurate velocities can be obtained by those with all levels of ultrasound experience. Care must be taken on image interpretation that velocities are obtained at an appropriate depth to ensure appropriate insonation of the MCA as well as in optimal alignment with the vessel to obtain the most accurate velocities. [ABSTRACT FROM AUTHOR]