Hematoma volume is a predictive factor of disturbed autoregulation after spontaneous intracerebral hemorrhage

Monitoring of cerebral blood flow autoregulation: physiologic basis, measurement, and clinical implications

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.

A Multi-Parametric Approach for Characterising Cerebral Haemodynamics in Acute Ischaemic and Haemorrhagic Stroke

BACKGROUND AND PURPOSE

Early differentiation between acute ischaemic (AIS) and haemorrhagic stroke (ICH), based on cerebral and peripheral hemodynamic parameters, would be advantageous to allow for pre-hospital interventions. In this preliminary study, we explored the potential of multiple parameters, including dynamic cerebral autoregulation, for phenotyping and differentiating each stroke sub-type.

METHODS

Eighty patients were included with clinical stroke syndromes confirmed by computed tomography within 48 h of symptom onset. Continuous recordings of bilateral cerebral blood velocity (transcranial Doppler ultrasound), end-tidal CO2 (capnography), electrocardiogram (ECG), and arterial blood pressure (ABP, Finometer) were used to derive 67 cerebral and peripheral parameters.

RESULTS

A total of 68 patients with AIS (mean age 66.8 ± SD 12.4 years) and 12 patients with ICH (67.8 ± 16.2 years) were included. The median ± SD NIHSS of the cohort was 5 ± 4.6. Statistically significant differences between AIS and ICH were observed for (i) an autoregulation index (ARI) that was higher in the unaffected hemisphere (UH) for ICH compared to AIS (5.9 ± 1.7 vs. 4.9 ± 1.8 p = 0.07); (ii) coherence function for both hemispheres in different frequency bands (AH, p < 0.01; UH p < 0.02); (iii) a baroreceptor sensitivity (BRS) for the low-frequency (LF) bands that was higher for AIS (6.7 ± 4.2 vs. 4.10 ± 2.13 ms/mmHg, p = 0.04) compared to ICH, and that the mean gain of the BRS in the LF range was higher in the AIS than in the ICH (5.8 ± 5.3 vs. 2.7 ± 1.8 ms/mmHg, p = 0.0005); (iv) Systolic and diastolic velocities of the affected hemisphere (AH) that were significantly higher in ICH than in AIS (82.5 ± 28.09 vs. 61.9 ± 18.9 cm/s), systolic velocity (p = 0.002), and diastolic velocity (p = 0.05).

CONCLUSION

Further multivariate modelling might improve the ability of multiple parameters to discriminate between AIS and ICH and warrants future prospective studies of ultra-early classification (<4 h post symptom onset) of stroke sub-types.

Hypothermia and temperature modulation for intracerebral hemorrhage (ICH): pathophysiology and translational applications

Background

Intracerebral hemorrhage (ICH) still poses a substantial challenge in clinical medicine because of the high morbidity and mortality rate that characterizes it. This review article expands into the complex pathophysiological processes underlying primary and secondary neuronal death following ICH. It explores the potential of therapeutic hypothermia as an intervention to mitigate these devastating effects.

Methods

A comprehensive literature review to gather relevant studies published between 2000 and 2023.

Discussion

Primary brain injury results from mechanical damage caused by the hematoma, leading to increased intracranial pressure and subsequent structural disruption. Secondary brain injury encompasses a cascade of events, including inflammation, oxidative stress, blood-brain barrier breakdown, cytotoxicity, and neuronal death. Initial surgical trials failed to demonstrate significant benefits, prompting a shift toward molecular mechanisms driving secondary brain injury as potential therapeutic targets. With promising preclinical outcomes, hypothermia has garnered attention, but clinical trials have yet to establish its definitive effectiveness. Localized hypothermia strategies are gaining interest due to their potential to minimize systemic complications and improve outcomes. Ongoing and forthcoming clinical trials seek to clarify the role of hypothermia in ICH management.

Conclusion

Therapeutic hypothermia offers a potential avenue for intervention by targeting the secondary injury mechanisms. The ongoing pursuit of optimized cooling protocols, localized cooling strategies, and rigorous clinical trials is crucial to unlocking the potential of hypothermia as a therapeutic tool for managing ICH and improving patient outcomes.

Are We Ready for Clinical Therapy based on Cerebral Autoregulation? A Pro-con Debate

Cerebral autoregulation (CA) is a physiological mechanism that maintains constant cerebral blood flow regardless of changes in cerebral perfusion pressure and prevents brain damage caused by hypoperfusion or hyperperfusion. In recent decades, researchers have investigated the range of systemic blood pressures and clinical management strategies over which cerebral vasculature modifies intracranial hemodynamics to maintain cerebral perfusion. However, proposed clinical interventions to optimize autoregulation status have not demonstrated clear clinical benefit. As future trials are designed, it is crucial to comprehend the underlying cause of our inability to produce robust clinical evidence supporting the concept of CA-targeted management. This article examines the technological advances in monitoring techniques and the accuracy of continuous assessment of autoregulation techniques used in intraoperative and intensive care settings today. It also examines how increasing knowledge of CA from recent clinical trials contributes to a greater understanding of secondary brain injury in many disease processes, despite the fact that the lack of robust evidence influencing outcomes has prevented the translation of CA-guided algorithms into clinical practice.

Predictive value of hyperglycemia on prognosis in spontaneous intracerebral hemorrhage patients

Background

Spontaneous intracerebral hemorrhage (ICH) is the second most common cause of stroke and accounts for approximately 15-20% of all new stroke cases. Hematoma expansion is a potentially important therapeutic target that is amenable to treatment and independently predict outcome. Hyperglycemia is frequent in ICH patients, and affects cerebrovascular function, increasing the risk of cerebral vascular rupture. We recruited 170 ICH patients to explore the high risk factors of mortality and the association between hyperglycemia and early hematoma expansion.

Methods

A retrospective analysis of 170 patients with ICH who were grouped by survival and blood glucose level, death group (35 cases) and survival group (135 cases); 77 cases in the hyperglycemic group and 93 cases in the normoglycemic group. Recorded parameters, such as age, gender, past medical history, blood glucose, serum calcium, hematoma volume, and hematoma expansion. Group comparison used t-test, rank sum test and Fisher exact test. After these, logistic regression analysis and receiver operating characteristic (ROC) curves were performed.

Results

Among 170 ICH subjects(130 males and 40 females)，35 died and 77 exhibited hyperglycaemia. Compared with the survival group, the death group presented with higher Original Intracerebral Hemorrhage Scale (OICH) score, greater blood glucose, larger hemorrhage volume and lower Glasgow Coma Scale (GCS) score. The occurrence of hematoma expansion and massive hemorrhage volume in the hyperglycemic group were higher than in the normoglycemic group(P < 0.05). After adjustment for confounders variables, multivariate logistic analysis showed that blood glucose was an independent predictor of hematoma expansion (adjusted odd ratio:8.04, 95%CI:3.89-16.63, P < 0.01). Fasting blood glucose had better predictive value for hematoma expansion (AUC:0.95, 95%CI:0.92-0.99, P < 0.01).

Conclusion

Hyperglycemia is associated with higher mortality risk and could be a potential marker in the prediction of hematoma expansion.

The utility of therapeutic hypothermia on cerebral autoregulation

Cerebral autoregulation (CA) dysfunction is a strong predictor of clinical outcome in patients with acute brain injury (ABI). CA dysfunction is a potential pathologic defect that may lead to secondary injury and worse functional outcomes. Early therapeutic hypothermia (TH) in patients with ABI is controversial. Many factors, including patient selection, timing, treatment depth, duration, and rewarming strategy, impact its clinical efficacy. Therefore, optimizing the benefit of TH is an important issue. This paper reviews the state of current research on the impact of TH on CA function, which may provide the basis and direction for CA-oriented target temperature management.

Impact of Cerebral Autoregulation Monitoring in Cerebrovascular Disease: A Systematic Review

Cerebral autoregulation (CA) prevents brain injury by maintaining a relatively constant cerebral blood flow despite fluctuations in cerebral perfusion pressure. This process is disrupted consequent to various neurologic pathologic processes, which may result in worsening neurologic outcomes. Herein, we aim to highlight evidence describing CA changes and the impact of CA monitoring in patients with cerebrovascular disease, including ischemic stroke, intracerebral hemorrhage (ICH), and aneurysmal subarachnoid hemorrhage (aSAH). The study was preformed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. English language publications were identified through a systematic literature conducted in Ovid Medline, PubMed, and Embase databases. The search spanned the dates of each database's inception through January 2021. We selected case-control studies, cohort observational studies, and randomized clinical trials for adult patients (≥ 18 years) who were monitored with continuous metrics using transcranial Doppler, near-infrared spectroscopy, and intracranial pressure monitors. Of 2799 records screened, 48 studies met the inclusion criteria. There were 23 studies on ischemic stroke, 18 studies on aSAH, 5 studies on ICH, and 2 studies on systemic hypertension. CA impairment was reported after ischemic stroke but generally improved after tissue plasminogen activator administration and successful mechanical thrombectomy. Persistent impairment in CA was associated with hemorrhagic transformation, malignant cerebral edema, and need for hemicraniectomy. Studies that investigated large ICHs described bilateral CA impairment up to 12 days from the ictus, especially in the presence of small vessel disease. In aSAH, impairment of CA was associated with angiographic vasospasm, delayed cerebral ischemia, and poor functional outcomes at 6 months. This systematic review highlights the available evidence for CA disruption during cerebrovascular diseases and its possible association with long-term neurological outcome. CA may be disrupted even before acute stroke in patients with untreated chronic hypertension. Monitoring CA may help in establishing individualized management targets in patients with cerebrovascular disease.

Regulation of cerebral blood flow in humans: physiology and clinical implications of autoregulation

Brain function critically depends on a close matching between metabolic demands, appropriate delivery of oxygen and nutrients, and removal of cellular waste. This matching requires continuous regulation of cerebral blood flow (CBF), which can be categorized into four broad topics: 1) autoregulation, which describes the response of the cerebrovasculature to changes in perfusion pressure; 2) vascular reactivity to vasoactive stimuli [including carbon dioxide (CO2)]; 3) neurovascular coupling (NVC), i.e., the CBF response to local changes in neural activity (often standardized cognitive stimuli in humans); and 4) endothelium-dependent responses. This review focuses primarily on autoregulation and its clinical implications. To place autoregulation in a more precise context, and to better understand integrated approaches in the cerebral circulation, we also briefly address reactivity to CO2 and NVC. In addition to our focus on effects of perfusion pressure (or blood pressure), we describe the impact of select stimuli on regulation of CBF (i.e., arterial blood gases, cerebral metabolism, neural mechanisms, and specific vascular cells), the interrelationships between these stimuli, and implications for regulation of CBF at the level of large arteries and the microcirculation. We review clinical implications of autoregulation in aging, hypertension, stroke, mild cognitive impairment, anesthesia, and dementias. Finally, we discuss autoregulation in the context of common daily physiological challenges, including changes in posture (e.g., orthostatic hypotension, syncope) and physical activity.

Cerebrovascular tone and resistance measures differ between healthy control and patients with acute intracerebral haemorrhage: exploratory analyses from the BREATHE-ICH study

Objective.Cerebral autoregulation impairment in acute neurovascular disease is well described. The recent BREATHE-ICH study demonstrated improvements in dynamic cerebral autoregulation, by hypocapnia generated by hyperventilation, in the acute period following intracranial haemorrhage (ICH). This exploratory analysis of the BREATHE-ICH dataset aims to examine the differences in hypocapnic responses between healthy controls and patients with ICH, and determine whether haemodynamic indices differ between baseline and hypocapnic states.Approach.Acute ICH patients were recruited within 48 h of onset and healthy volunteers were recruited from a university setting. Transcranial Doppler measurements of the middle cerebral artery were obtained at baseline and then a hyperventilation intervention was used to induce hypocapnia. Patients with ICH were then followed up at 10-14 D post-event for repeated measurements.Main results.Data from 43 healthy controls and 12 patients with acute ICH met the criteria for statistical analysis. In both normocapnic and hypocapnic conditions, significantly higher critical closing pressure and resistance area product were observed in patients with ICH. Furthermore, critical closing pressure changes were observed to be sustained at 10-14 D follow up. During both the normocapnic and hypocapnic states, reduced autoregulation index was observed bilaterally in patients with ICH, compared to healthy controls.Significance.Whilst this exploratory analysis was limited by a small, non-age matched sample, significant differences between ICH patients and healthy controls were observed in factors associated with cerebrovascular tone and resistance. These differences suggest underlying cerebral autoregulation changes in ICH, which may play a pivotal role in the morbidity and mortality associated with ICH.

Effects of early mobilization on short-term blood pressure variability in acute intracerebral hemorrhage patients: A protocol for randomized controlled non-inferiority trial

BACKGROUND

Early out-of-bed mobilization may improve acute post-intracerebral hemorrhage (ICH) outcomes, but hemodynamic instability may be a concern. Some recent studies have showed that an increase in mean systolic blood pressure (SBP) and high blood pressure variability (BPV), high standard deviation of SBP, may lead to negative ICH outcomes. Therefore, we investigated the impact of an early mobilization (EM) protocol on mean SBP and BPV during the acute phase.

METHODS

The study was an assessor-blinded, randomized controlled non-inferiority study. The participants were in An Early Mobilization for Acute Cerebral Hemorrhage trial and were randomly assigned to undergo EM or a standard early rehabilitation (SER) protocol within 24 to 72 hour after ICH onset at the stroke center. The EM and SER groups each had 30 patients. 24-measurement SBP were recorded on days 2 and 3 after onset, and SBP were recorded three times daily and during rehabilitation on days 4 through 7. The two groups' mean SBP and BPV under three different time frames (days 2 and 3 during the acute phase, and days 4 through 7 during the late acute phase) were calculated and compared.

RESULTS

At baseline, the two groups' results were similar, with the exception being that the mean time to first out-of-bed mobilization after symptom onset was 51.60 hours (SD 14.15) and 135.02 hours (SD 33.05) for the EM group and SER group, respectively (P < .001). There were no significant differences in mean SBP and BPV during the acute and late acute phase between the two groups for the three analyses (days 2, 3, and 4 through 7) (P > .05).

CONCLUSIONS

It is safe to implement the EM protocol within 24 to 72 hour of onset for mild-moderate ICH patients during the acute phase.

Diffuse Cerebral Edema After Moyamoya Disease-Related Intracerebral Hemorrhage: A Case Report

Moyamoya disease (MMD) is a rare, progressive occlusive disease characterized by bilateral internal carotid artery hypoplasia that often presents with ischemic stroke and intracerebral hemorrhage (ICH). Although MMD-related ICH is generally managed similarly to spontaneous ICH, we present a case in which standard management strategies may have led to an unprecedented devastating outcome. A 37-year-old female without any previous medical history presented with headache and right-sided weakness. A computed tomography (CT) scan revealed a large left basal ganglia ICH. Vessel imaging revealed diffuse narrowing of the entire anterior circulation with prominent leptomeningeal collaterals consistent with MMD. The patient's systolic blood pressure was kept under 140 mmHg. During the hospitalization, she became hypocarbic while being trialed on pressure support ventilation. Several hours later, she developed fixed and dilated pupils. Repeat CT head showed new diffuse cerebral edema with tonsillar herniation. Despite hyperosmolar therapy, paralytics, pentobarbital, and cerebrospinal fluid diversion, no improvement was noted. Unfortunately, brain MRI revealed multifocal brainstem infarcts with superimposed Duret hemorrhages. Herein, we report diffuse cerebral edema as a complication of MMD-related ICH. We hypothesize that disruptions of delicate cerebral autoregulatory mechanisms led to extensive hypoxic-ischemic injury. In the setting of ICH, aggressive blood pressure management coupled with relative hypocapnia may have likely caused vasoconstriction of poorly compliant arteries leading to worsened cerebral blood flow and ischemia. Therefore, because of its complex pathophysiology, strict adherence to eucapnia should be maintained in MMD-related ICH.

Impact of serum omentin-1 concentrations on functional outcome among acute intracerebral hemorrhage patients

BACKGROUND

Reduced serum omentin-1 concentrations might be related to an increased risk for poor functional outcome after acute ischemic stroke. We intended to explore whether serum omentin-1 could be a promising prognostic biomarker for acute intracerebral hemorrhage.

METHODS

A total of 104 consecutive patients with hemorrhagic stroke underwent 90-day follow-up. The modified Rankin scale score >2 was evaluated as worse prognosis. A multivariable logistic model was conFig.d for assessing the relationship between serum omentin-1 concentrations and functional outcome.

RESULTS

Serum omentin-1 concentrations, with the median value of 147.9 ng/ml (interquartile range, 114.7-199.8 ng/ml), were substantially declined with rising modified Rankin scale scores (P < 0.001). Serum omentin-1 concentrations <147.9 ng/ml was independently related to higher risk of 90-day worse prognosis (odds ratio, 3.789; 95% confidence interval, 1.819-8.608; P = 0.018). Under receiver operating characteristic curve, an optimal value of serum omentin-1 concentrations was selected as 179.7 ng/ml, which yielded 0.88 sensitivity value and 0.70 specificity value for discriminating patients at risk of 90-day worse prognosis (area under curve, 0.82; 95% confidence interval, 0.73-0.89).

CONCLUSIONS

Lower serum omentin-1 concentrations are closely associated with poor functional outcome after hemorrhagic stroke, substantializing serum omentin-1 as a potential prognostic biomarker for acute intracerebral hemorrhage.

Can we assess dynamic cerebral autoregulation in stroke patients with high rates of cardiac ectopicity?

It is unclear whether physiological recordings containing high numbers of ectopic heartbeats can be used to measure the cerebral autoregulation (CA) of blood flow. This study evaluated the utility of such data for assessing dynamic CA capacity. Physiological recordings of cerebral blood flow velocity, heart rate, end-tidal CO₂ and beat-to-beat blood pressure from acute ischaemic stroke (AIS) patients (n = 46) containing ectopic heartbeats of varying number (0.2 to 25 occurrences per minute) were analysed. Dynamic CA was determined using the autoregulation index (ARI) and the normalised mean square error (NMSE) was used to evaluate the fitting of the step response between BP and CBFV to Tiecks' model. We fitted linear mixed models on the CA variables incorporating ectopic burden, age, sex and hemisphere as predictor variables. Ectopic activity demonstrated an association with mean coherence (p = 0.006) but not with ARI (p = 0.162), impaired CA based on dichotomised ARI (p = 0.859) or NMSE (p = 0.671). Dynamic CA could be reliably assessed in AIS patients using physiological recordings with high rates of cardiac ectopic activity. This provides supportive data for future studies evaluating CA capability in AIS patients, with the potential to develop more individualised treatment strategies. Graphical Abstract.

Assessment of cerebral autoregulation in stroke: A systematic review and meta-analysis of studies at rest

Dynamic cerebral autoregulation (dCA) has been shown to be impaired in cerebrovascular diseases, but there is a lack of consistency across different studies and the different metrics that have been proposed for assessment. We performed a systematic review and meta-analyses involving assessment of dCA in ischemic and hemorrhagic stroke. Thirty-three articles describing assessment of dCA with transfer function analysis (TFA) were included, with meta-analyses performed for derived parameters of gain, phase and autoregulation index (ARI). A total of 1233 patients were pooled from 12 studies on acute ischemic stroke (AIS) and two studies on intracerebral hemorrhage (ICH). In comparison with controls, TFA phase of AIS was significantly reduced (nine studies), in both hemispheres (P < 0.0001). TFA gain provided inconsistent results, with reduced values in relation to controls, for both hemispheres. The ARI (six studies) was reduced compared to controls, in both hemispheres (P < 0.005). In ICH, gain showed higher values compared to controls for the unaffected (P = 0.01), but not for the affected hemisphere. Meta-analyses in AIS have demonstrated that phase and the ARI index can show highly significant differences in comparison with healthy controls, while ICH have been limited by the scarcity of studies and the diversity of units adopted for gain.

Feasibility of improving cerebral autoregulation in acute intracerebral hemorrhage (BREATHE-ICH) study: Results from an experimental interventional study

Background

Cerebral autoregulation is impaired in a multitude of neurological conditions. Increasingly, clinical studies are correlating the nature of this impairment with prognostic markers. In acute intracerebral hemorrhage, impairment of cerebral autoregulation has been associated with worsening clinical outcomes including poorer Glasgow Coma Score and larger hematoma volume. Hypocapnia has been shown to improve cerebral autoregulation despite concerns over hypoperfusion and consequent ischemic risks, and it is therefore hypothesized that hypocapnia (via hyperventilation) in acute intracerebral hemorrhage may improve cerebral autoregulation and consequently clinical outcome.

Aims

To assess the feasibility and acceptability of the first cerebral autoregulation-targeted intervention in acute intracerebral hemorrhage utilizing a simple bed-side hyperventilatory maneuver.

Methods

Twelve patients with acute intracerebral hemorrhage within 48 h of onset were enrolled. The experimental setup measured cerebral blood flow velocity (transcranial Doppler), blood pressure (Finometer), and end-tidal CO2 (EtCO2, capnography) at baseline, and in response to hypocapnia (−5 mmHg below baseline) achieved via a 90-s hyperventilatory maneuver. Cerebral autoregulation was evaluated with transfer function analysis and autoregulatory index calculations.

Results

We observed tolerance to the protocol in a cohort of mild (National Institutes of Health Scale 4) supratentorial intracerebral hemorrhage patients with small volume hematomas without intraventricular extension. Importantly, a significant difference was noted between ipsilateral autoregulatory index at baseline 4.8 (1.7) and autoregulatory index during hypocapnic intervention 7.0 (0.8) (p = 0.0004), reflecting improved cerebral autoregulation, though a dose-dependent effect of EtCO2 on autoregulatory index was not observed.

Conclusions

In this small study, there was no observed effect on 14-day death and disability in recruited participants. This is the first report of improvement in cerebral autoregulation in acute intracerebral hemorrhage using a non-invasive interventional maneuver, through induction of hypocapnia via hyperventilation. ClinicalTrials.gov Identifier: NCT03324321 URL: https://clinicaltrials.gov/ct2/show/NCT03324321

Serum lipoprotein-associated phospholipase A2 as a promising prognostic biomarker in association with 90-day outcome of acute intracerebral hemorrhage

BACKGROUND

Lipoprotein-associated phospholipase A2 (Lp-PLA2) is reflective of vascular inflammation and plays a role in the pathophysiology of cerebrovascular disease. We determine usefulness of serum Lp-PLA2 as a prognostic biomarker for intracerebral hemorrhage (ICH).

METHODS

In this prospective, observational study, serum Lp-PLA2 concentrations were detected among 164 patients with acute spontaneous basal ganglia hemorrhage and 164 healthy controls. Using multivariate analysis, we analyzed its association with poor outcome (modified Rankin Scale >2) at poststroke 90 days and hemorrhagic severity indicated by National Institutes of Health Stroke Scale (NIHSS) score and hematoma volume.

RESULTS

Serum Lp-PLA2 concentrations were remarkably higher in patients than in controls. Lp-PLA2 concentrations were independently correlated with NIHSS score (t = 5.095, P < .001) and hematoma volume (t = 2.850, P = .005). At 90-day follow-up, 85 patients (51.8%) had poor outcome. Under receiver operating characteristic curve, serum Lp-PLA2 showed a significant prognostic discriminatory capability (AUC, 0.813; 95% CI, 0.744-0.869). Serum Lp-PLA2 concentrations ≥304 ng/ml was an independent predictor associated with poor outcome (OR 7.052; 95% CI 1.971-25.228).

CONCLUSIONS

Rising serum Lp-PLA2 concentrations are closely hemorrhagic severity and clinical outcomes after ICH, substantializing serum Lp-PLA2 as a potential prognostic biomarker of ICH.

Cerebral autoregulation in hemorrhagic stroke: A systematic review and meta-analysis of transcranial Doppler ultrasonography studies

PURPOSE

International guidelines advocate intensive blood pressure (BP) lowering within 6 hours of acute intracerebral hemorrhage (ICH) to a target systolic BP of 130-140 mm Hg, though more intensive lowering may be associated with adverse outcome. Observational studies suggest impaired cerebral autoregulation (CA) following ICH. Transcranial Doppler ultrasonography (TCD), alongside continuous BP monitoring, provides a noninvasive bedside investigation that offers detailed perspectives on physiological perturbations post-acute ICH. This systematic review and meta-analysis focuses on all TCD studies of CA in ICH.

METHODS

MEDLINE, EMBASE, and CENTRAL were searched for studies of hemorrhagic stroke and blood flow measurement.

RESULTS

Eight studies met inclusion criteria (293 ICH patients); CA was impaired up to 12-days post-acute ICH. Impaired CA was evidenced by reduced transfer function analysis phase and higher mean flow correlation values: these were associated with worsened clinical parameters including ICH-volume and Glasgow Coma Scale. Meta-analysis of CBV demonstrated that, compared to controls, mean CBV was significantly lower in the ipsilateral (49.7 vs 64.8 cm s^-1 , Z = 4.26, P < .0001) and contralateral hemispheres following ICH (51.5 vs 64.8 cm s^-1 , Z = 3.44, P = .0006).

CONCLUSION

Lower mean CBV in combination with impaired CA may have implications for more intensive BP lowering and warrants further studies examining such strategies on cerebral blood flow and its regulatory mechanisms.

Compromised Dynamic Cerebral Autoregulation in Patients With Depression

Background: Patients with depression tend to have various comorbid neurological symptoms, but the mechanisms remain unclear. The purpose of this study was to analyze the characteristics of dynamic cerebral autoregulation in depressed patients. Methods: Patients (aged ≥ 18 years) who were diagnosed with depression [17-item Hamilton Depression Rating Scale (HAMD) > 17] or suspected of depression (HAMD > 7) were enrolled in this study. Medically healthy volunteers were recruited as controls. The subjects also received the 7-item HAMD. We simultaneously recorded noninvasive continuous arterial blood pressure and bilateral middle cerebral artery blood flow velocity from each subject. Cerebral autoregulation was assessed by analyzing the phase difference using transfer function analysis. Results: This study enrolled 54 patients with suspected depression, 45 patients with depression, and 48 healthy volunteers. The mean phase difference values were significantly lower in the patients with depression (F = 9.071, P < 0.001). In the multiple regression analysis, depression was negatively correlated with the phase difference values. Conclusions: Dynamic cerebral autoregulation was compromised in patients with depression and negatively correlated with the depression score. Improving dynamic cerebral autoregulation may be a potential therapeutic method for treating the neurological symptoms of depression.

Cerebral Autoregulation in Stroke

PURPOSE OF REVIEW

Cerebral autoregulation (CA) is a mechanism that maintains cerebral blood flow constant despite fluctuations in systemic arterial blood pressure. This review will focus on recent studies that measured CA non-invasively in acute cerebrovascular events, a feature unique to the transcranial Doppler ultrasound. We will summarize the rationale for CA assessment in acute cerebrovascular disorders and specifically evaluate the existing data on the value of CA measures in relation to clinical severity, guiding management decisions, and prognostication.

RECENT FINDINGS

Existing data suggest that CA is generally impaired in various cerebrovascular disorders. In patients with small vessel ischemic stroke, CA has been shown to be impaired in both hemispheres, whereas in large territorial strokes, CA impairment has been limited to the affected hemisphere. In these latter patients, impaired CA is also predictive of secondary complications such as hemorrhagic transformation and cerebral edema, hence worse functional outcome. In patients with carotid stenosis, impaired CA may also be associated with a higher ipsilateral hemispheric stroke risk. CA is also strongly linked to outcome in patients with intracranial hemorrhage. In patients with intraparenchymal hemorrhage, CA impairment correlated with clinical and imaging severity, whereas in those with subarachnoid hemorrhage, CA measures have a predictive value for development of delayed cerebral ischemia and radiographic vasospasm. Assessment of CA is increasingly more accessible in acute cerebrovascular disorders and promises to be a valuable measure in guiding hemodynamic management and predicting secondary complication, thus enhancing the care of these patients in the acute setting.

Factors Associated With Remote Diffusion-Weighted Imaging Lesions in Spontaneous Intracerebral Hemorrhage

Background and purpose

Remote diffusion-weighted imaging lesions (R-DWILs) have been detected in patients with spontaneous intracerebral hemorrhage (ICH) and may be correlated with clinical outcome. However, the mechanisms and characteristics of R-DWILs have not been fully elucidated. In this study, we sought to demonstrate the clinical characteristics of R-DWILs in spontaneous ICH.

Methods

We prospectively collected data with spontaneous ICH patients from November 2016 to December 2017. In these patients, cerebral magnetic resonance imaging was performed within 28 days after ICH onset. R-DWIL was defined as a hyperintensity signal in diffusion-weighted imaging with corresponding hypointensity in apparent diffusion coefficient, and at least 20 mm apart from the hematoma. We compared two groups of patients with or without R-DWIL with the demographic and clinical characteristics, laboratory parameters, and imaging characteristics, by using univariate and multivariate analysis.

Results

Of the 222 patients enrolled, a total of 75 R-DWILs were observed in 41 patients (18.5%). Among these lesions, the cortical and subcortical areas were the predominant locations with a proportion of 77.3%. The median diameter of R-DWILs was 7 mm (range 2–20 mm). Twelve patients were found having more than one lesion, with five among which showed R-DWILs in multiple cerebral arterial territories. In multivariate modeling, higher fasting glucose (OR 1.231; 95% CI 1.035–1.465; p = 0.019) and more severe white matter hyperintensity (WMH) (OR 6.589; 95% CI 2.975–14.592; p < 0.001) were independent factors related to the presence of R-DWILs.

Conclusion

In our study, approximately one-fifth of ICH patients showed coexistence of R-DWIL. Higher fasting glucose and more severe WMH were associated with R-DWIL occurrence in spontaneous ICH.

Feasibility of Improving Cerebral Autoregulation in Acute Intracerebral Haemorrhage (BREATHE-ICH) study: a protocol for an experimental interventional study

INTRODUCTION

Cerebral autoregulation (CA) is impaired in a multitude of neurological conditions. Increasingly, clinical studies are correlating the nature of this impairment with prognostic markers. In acute intracerebral haemorrhage (ICH), impairment of CA has been associated with worsening clinical outcomes including poorer Glasgow Coma Score and larger haematoma volume. Hypocapnia has been shown to improve CA despite concerns over hypoperfusion and consequent ischaemic risks, and it is therefore hypothesised that hypocapnia (via hyperventilation) in acute ICH may improve CA and consequently clinical outcome. BREATHE-ICH is a CA-targeted interventional study in acute ICH utilising a simple bedside hyperventilatory manoeuvre.

METHODS AND ANALYSIS

Patients with acute ICH within 48 hours of onset will be included. The experimental set-up measures cerebral blood flow (cerebral blood velocity, transcranial Doppler), blood pressure (Finometer) and end tidal carbon dioxide (capnography) at baseline, and in response to hypocapnia (-5 mm and -10 mm Hg below baseline) achieved via a 90 s hyperventilatory manoeuvre. Autoregulation is evaluated with transfer function analysis and autoregulatory index calculations. Important classical endpoints associated with this before and after interventional study include death and disability at 14 days and the proportion of recruited individuals able to comply with the full measurement protocol.

ETHICS AND DISSEMINATION

A favourable opinion was granted by the East Midlands-Nottingham 1 Research Ethics Committee (17/EM/0283). It is anticipated that the results of this study will be presented at national and international meetings, with reports being published in journals during late 2018.

TRIAL REGISTRATION NUMBER

NCT03324321.