Fixed Compared With Autoregulation-Oriented Blood Pressure Thresholds After Mechanical Thrombectomy for Ischemic Stroke

Exploring the optimal lower blood pressure boundary during endovascular thrombectomy in patients with large vessel occlusion

BACKGROUND

Current guidelines advocate for maintaining BP level below 180/105 mmHg during EVT, determining the safe lower boundary remains primarily consensus-driven by experts. This study aims to delve into the correlation between various targets of lower boundary for systolic and diastolic BP (SBP and DBP) during EVT and 3-month functional outcomes.

METHODS

A cohort study was conducted across two EVT-capable centers, enrolling patients with large artery occlusion undergoing EVT within 8 h of stroke onset. Mean BP values during EVT were meticulously recorded, and logistic regression models were utilized to evaluate the correlation between outcomes and diverse lower boundary targets for SBP and DBP. Additionally, logistic regression models investigated the relationship between periprocedural BP variability and subsequent outcomes.

RESULTS

Among the 201 patients included, having a SBP higher than 130 or 140 mmHg showed an independent association with increased good functional outcomes at 3 months (adjusted odds ratio, aOR 2.80, 95% Cis, 1.26-6.39 for 140 mmHg; aOR 2.34, 95% Cis, 1.03-5.56 for 130 mmHg). Additionally, an SBP exceeding 130 mmHg was correlated with decreased 3-month mortality (aOR, 0.24, 95% CI 0.07-0.74). No significant relationship was observed between DBP and functional outcomes. Patients with higher periprocedural SBP coefficient variance exhibited a decreased rate of good functional outcomes at 3 months (aOR, 0.42, 95% CI, 0.18-0.96).

CONCLUSION

A SBP range above 130-140 mmHg could potentially serve as a safe lower boundary during EVT, while minimizing BP fluctuations may correlate with improved post-EVT functional outcomes.

Modeling the Mechanisms of Non-Neurogenic Dynamic Cerebral Autoregulation

OBJECTIVE

Dynamic cerebral autoregulation (dCA) refers to a collection of mechanisms that act to maintain steady state cerebral blood flow (CBF) near constant despite changes in arterial blood pressure (ABP), but which is known to become impaired in various cerebrovascular diseases. Currently, the mechanisms of dCA and how they are affected in different physiological conditions are poorly understood. The objective of this study was to disentangle the magnitudes and time scales of the myogenic and metabolic responses of dCA, in order to investigate how each mechanism is affected in impaired dCA.

METHODS

A physiological model of dCA was developed, where both the myogenic and metabolic responses were represented by a gain and time constant. Model parameters were optimized with pressure-flow impulse responses under normocapnic, thigh cuff, and hypercapnic conditions. The impulse responses were derived by applying transfer function analysis (TFA) to experimental recordings of ABP (Finapres), end-tidal CO2 (capnograph), and CBF velocity (transcranial doppler ultrasound in bilateral middle cerebral arteries).

RESULTS

The myogenic gain to time constant ratio was significantly smaller (p-values < 0.001 using both univariate and multivariate TFA), and the metabolic time constant was significantly larger (p-values < 0.001 using both univariate and multivariate TFA) in hypercapnia compared to normocapnia.

CONCLUSION

Both the myogenic and metabolic responses were shown to be affected in impaired dCA, and the metabolic response was shown to be slowed down.

SIGNIFICANCE

This study contributes to the understanding of the complexities of dCA and how it is affected in different physiological conditions.

Association of blood pressure and outcomes differs upon cerebral perfusion post-thrombectomy in patients with acute ischemic stroke

BACKGROUND

The relationship between post-endovascular thrombectomy (EVT) blood pressure (BP) and outcomes in patients with acute ischemic stroke (AIS) remains contentious. We aimed to explore whether this association differs with different cerebral perfusion statuses post-EVT.

METHODS

In a multicenter observational study of patients with AIS with large vessel occlusion who underwent EVT, we enrolled those who accepted CT perfusion (CTP) imaging within 24 hours post-EVT. We recorded post-EVT systolic (SBP) and diastolic BP. Patients were stratified into favorable perfusion and unfavorable perfusion groups based on the hypoperfusion intensity ratio (HIR) on CTP. The primary outcome was good functional outcome (90-day modified Rankin Scale score of ≤3). Secondary outcomes included early neurological deterioration, infarct size growth, and symptomatic intracranial hemorrhage.

RESULTS

Of the 415 patients studied (mean age 62 years, 75% male), 233 (56%) achieved good functional outcomes. Logistic regression showed that post-EVT HIR and 24-hour mean SBP were significantly associated with functional outcomes. Among the 326 (79%) patients with favorable perfusion, SBP <140 mmHg was associated with a higher percentage of good functional outcomes compared with SBP ≥140 mmHg (68% vs 52%; aOR 1.70 (95% CI 1.00 to 2.89), P=0.04). However, no significant difference was observed between SBP and functional outcomes in the unfavorable perfusion group. There was also no discernible difference between SBP and secondary outcomes across the different perfusion groups.

CONCLUSIONS

In patients with favorable perfusion post-EVT, SBP <140 mmHg was associated with good functional outcomes, which underscores the need for further investigations with larger sample sizes or a more individualized BP management strategy.

CLINICAL TRIAL REGISTRATION

ChiCTR1900022154.

Intensive Versus Standard Blood Pressure Management after Endovascular Therapy for Acute Ischemic Stroke: A Systematic Review and Meta-analysis

Prospective clinical studies on blood pressure (BP) management targets after endovascular therapy (EVT) for acute ischemic stroke (AIS) have recently been published. Our objective was to assess the impact on clinical outcomes of BP management guided by established systolic BP (SBP) targets within the first 24 hours after successful EVT. Four randomized controlled trials (RCTs) including 1556 participants across 5 SBP target settings identified from 5 databases up to September 6, 2023 were included in this systematic review and meta-analysis. All the intensive SBP target groups in these RCTs were combined to facilitate head-to-head comparisons. Patients receiving intensive SBP management had lower risk of 90-day functional independence as assessed by the modified Rankin scale score (relative risk [RR], 0.81; 95% confidence interval [CI], 0.72 to 0.91; I2 , 12%), excellent outcomes (RR,0.86; 95% CI, 0.75 to 0.99; I2 , 7%), favorable outcomes (RR, 0.85; 95% CI, 0.78 to 0.92; I2 , 0%), and quality of life (standardized mean difference, -0.22; 95% CI, -0.35 to -0.10; I 2 ,0%). There were no differences in the probability of any intracerebral hemorrhage (RR, 1.04; 95% CI, 0.92 to 1.19; I2 ,0%), symptomatic intracerebral hemorrhage (RR, 1.10; 95% CI, 0.76 to 1.60; I2 , 0%), stroke-related death (RR, 1.16; 95% CI, 0.80 to 1.68; I2 , 0%), or parenchymal hematoma (RR, 1.71; 95% CI, 0.74 to 3.98; I2 , 47%) between SBP targets. This meta-analysis provides evidence from RCTs suggesting that intensive SBP control (target<160 mm Hg) may be detrimental to clinical outcomes in AIS patients with successful reperfusion after EVT.

Individualized autoregulation-guided arterial blood pressure management in neurocritical care

Cerebral autoregulation (CA) is the physiological process by which cerebral blood flow is maintained during fluctuations in arterial blood pressure (ABP). There are various validated methods to measure CA, either invasively, with intracranial pressure or brain tissue oxygenation monitors, or noninvasively, with transcranial Doppler ultrasound or near-infrared spectroscopy. Utilizing these monitors, researchers have been able to discern CA patterns in several pathological states, such as but not limited to acute ischemic stroke, spontaneous intracranial hemorrhage, aneurysmal subarachnoid hemorrhage, sepsis, and post-cardiac arrest, and they have found CA to be altered in these patients. CA disturbances predispose patients suffering from these ailments to worse outcomes. Much focus has been placed on CA monitoring in these populations, with an emphasis on arterial blood pressure optimization. Many guidelines recommend universal static ABP targets; however, in patients with altered CA, these targets may make them susceptible to hypoperfusion and further neurological injury. Based on this observation, there has been much investigation on individualized ABP goals and their effect on clinical outcomes. The scope of this review includes (1) a summary of the physiology of CA in healthy adults; (2) a review of the evidence on CA monitoring in healthy individuals; (3) a summary of CA changes and its effect on outcomes in various diseased states including acute ischemic stroke, spontaneous intracranial hemorrhage, aneurysmal subarachnoid hemorrhage, sepsis and meningitis, post-cardiac arrest, hypoxic-ischemic encephalopathy, surgery, and moyamoya disease; and (4) a review of the current evidence on individualized ABP changes in various patient populations.

Safety and Efficacy of Intensive Blood Pressure-Lowering After Successful Endovascular Therapy in AIS: A Meta-Analysis

OBJECTIVES

Higher blood pressure has been proven to be associated with poorer functional outcomes after successful reperfusion by EVT. However, the effect of intensive blood pressure-lowering regimens in these patients remains controversial and ambiguous in clinical practice. We propose further analysis aimed at determining the effect of an intensive blood pressure-lowering regimen after EVT in AIS.

METHODS

The protocol registered in PROSPERO CRD42023360989. We performed a systematic search that was comprehensively executed in online databases for studies published up to June 2022. Eligibility criteria were established based on the PICOS model. The Cochrane risk of bias algorithm was used to evaluate the risk of bias. The effect models were applied to calculate the pooled ORs and CIs via Review Manager 5.4 software.

RESULTS

A total of 1582 citations were identified, 3 randomized clinical trials and 2 retrospective cohort studies were included. Data from 3211 patients were analyzed. We revealed that intensive blood pressure-lowering interventions could significantly reduce symptomatic intraparenchymal hemorrhage compared with standard blood pressure lowering. Nevertheless, favorable functional outcome, poor outcome, all-cause mortality within 3 months and intraparenchymal hemorrhage in 24 hours showed no significant differences. Subgroup analysis revealed the variability of systolic blood pressure within 24 hours after EVT was not associated with odds of poor outcome and intraparenchymal hemorrhage.

CONCLUSIONS

Based on the current evidence, intensive blood pressure-lowering regimen was superior to standard blood pressure-lowering regimen for a reduced risk of symptomatic intraparenchymal hemorrhage in AIS patients treated with EVT, but there was no statistically significant difference found between the 2 regimens for the other outcomes.

Factors Influencing Nerinetide Effect on Infarct Volume in Patients Without Alteplase in the Randomized ESCAPE-NA1 Trial

BACKGROUND

In the ESCAPE-NA1 trial (Efficacy and Safety of Nerinetide for the Treatment of Acute Ischemic Stroke), treatment with nerinetide was associated with a smaller infarct volume among patients who did not receive intravenous alteplase. We assessed the effect of nerinetide on the surrogate imaging outcome of final infarct volume in patients who did not receive intravenous alteplase and explored predictors of outcome and modifiers of nerinetide's effect on infarct volume.

METHODS

ESCAPE-NA1 was a multicenter, randomized trial in which patients with acute stroke with a baseline Alberta Stroke Program Early CT Score >4, undergoing endovascular thrombectomy, were randomized to receive intravenous nerinetide or placebo. Patients not receiving intravenous alteplase were included in this post hoc secondary analysis of the trial data. Final infarct volume was manually segmented on 24-hour noncontrast computed tomography or diffusion-weighted magnetic resonance imaging. Predictors of final infarct volume were identified using multivariable linear regression with cubic-root-transformed infarct volume as the dependent variable. Evidence of treatment-by-predictor interaction was tested by including interaction terms in the model.

RESULTS

Four hundred forty-six patients (219 who received nerinetide and 227 who received a placebo) out of a total of 1105 enrolled patients were included in this secondary post hoc analysis of the randomized ESCAPE-NA1 trial. Nerinetide was a strong predictor of smaller infarct volume (adjusted β coefficient, -0.35 [95% CI, -0.67 to -0.02]). Other predictors of smaller infarct volume were history of hypertension, good pial collateral filling on multiphase computed tomography angiography, a middle cerebral artery occlusion compared with an internal carotid artery occlusion, lower baseline National Institutes of Health Stroke Scale score, lower baseline systolic blood pressure, lower baseline serum glucose, shorter onset-to-randomization time, and higher Alberta Stroke Program Early CT Score. There was evidence of a treatment-by-systolic blood pressure and treatment-by-anesthesia interaction: nerinetide attenuated the negative effects of elevated baseline (Pinteraction=0.02) and postdose (Pinteraction=0.04) systolic blood pressure and use of general anesthesia (Pinteraction=0.06) on final infarct volume. We observed a marginally significant interaction with reperfusion status, such that nerinetide may attenuate the harmful effect of poor reperfusion status on infarct volume (Pinteraction=0.08).

CONCLUSIONS

Nerinetide treatment was strongly associated with smaller final infarct volumes among patients not cotreated with alteplase. The reduction in infarct volume was greater among patients with poor prognostic factors.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02930018.

Regional dynamic cerebral autoregulation across anterior and posterior circulatory territories: A detailed exploration and its clinical implications

Cerebral autoregulation (CA) is the mechanism that maintains stable cerebral blood flow (CBF) despite fluctuations in systemic blood pressure, crucial for brain homeostasis. Recent evidence highlights distinct regional variations in CA between the anterior (carotid) and posterior (vertebrobasilar) circulations. Non-invasive neuromonitoring techniques, such as transcranial Doppler, transfer function analysis, and near-infrared spectroscopy, facilitate the dynamic assessment of CBF and autoregulation. Studies indicate a robust autoregulatory capacity in the anterior circulation, characterized by rapid adjustments in vascular resistance. On the contrary, the posterior circulation, mainly supplied by the vertebral arteries, may have a lower autoregulatory capacity. in acute brain injuries such as intracerebral and subarachnoid hemorrhage, and traumatic brain injuries, dynamic CA can be significantly altered in the posterior circulation. Proposed physiological mechanisms of impaired CA in the posterior circulation include: (1) Decreased sympathetic innervation of the vasculature impairing compensatory vasoreactivity; (2) Endothelial dysfunction; (3) Increased cerebral metabolic rate of oxygen consumption within the visual cortex causing CBF-metabolism (i.e., neurovascular) uncoupling; and (4) Impaired blood-brain barrier integrity leading to impaired astrocytic mediated release of vasoactive substances (e.g. nitric oxide, potassium, and calcium ions). Furthermore, more research is needed on the effects of collateral circulation, as well as the circle of Willis variants, such as the fetal-type posterior cerebral artery, on dynamic CA. Improving our understanding of these mechanisms is crucial to improving the diagnosis, prognosis, and management of various cerebrovascular disorders.

Cerebral autoregulation in pediatric and neonatal intensive care: A scoping review

Deranged cerebral autoregulation (CA) is associated with worse outcome in adult brain injury. Strategies for monitoring CA and maintaining the brain at its 'best CA status' have been implemented, however, this approach has not yet developed for the paediatric population. This scoping review aims to find up-to-date evidence on CA assessment in children and neonates with a view to identify patient categories in which CA has been measured so far, CA monitoring methods and its relationship with clinical outcome if any. A literature search was conducted for studies published within 31st December 2022 in 3 bibliographic databases. Out of 494 papers screened, this review includes 135 studies. Our literature search reveals evidence for CA measurement in the paediatric population across different diagnostic categories and age groups. The techniques adopted, indices and thresholds used to assess and define CA are heterogeneous. We discuss the relevance of available evidence for CA assessment in the paediatric population. However, due to small number of studies and heterogeneity of methods used, there is no conclusive evidence to support universal adoption of CA monitoring, technique, and methodology. This calls for further work to understand the clinical impact of CA monitoring in paediatric and neonatal intensive care.

Guideline-recommended basic parameter adherence in neurocritical care stroke patients: Observational multicenter individual participant data analysis

INTRODUCTION

Neurocritical care patients with neurovascular disease often face poor long-term outcomes, highlighting the pivotal role of evidence-based interventions. Although International Guidelines emphasize managing basic physiological parameters like temperature, blood glucose, blood pressure, and oxygen levels, physician adherence to these targets remains uncertain. This study aimed to assess adherence to guideline-based treatment targets for basic physiological parameters in neurocritical care.

PATIENTS AND METHODS

This multicenter observational study was conducted across eight tertiary University Hospitals in Germany analyzed 474 patients requiring mechanical ventilation (between January 1st and December 31st, 2021). Adherence was defined as the rate of measurements within therapeutic ranges for systolic blood pressure (situation-adapted), mean blood pressure (MAP, 60-90 mmHg), glucose levels (80-180 mg/dl), body temperature (<37.5°C), partial arterial pressure of oxygen (PaO2) 80-120 mmHg und partial arterial pressure of carbon dioxide (PaCO2) 35-45 mmHg during the initial 96 h of hospitalization in 4 hour-intervals.

RESULTS

Overall, 70.7% of all measurements were within the predetermined therapeutic ranges including SBP (71.3%), temperature (68.3%), MAP (71.4%), PaO2 (65.2%), PaCO2 (75.0%) and blood glucose (80.7%).

DISCUSSION AND CONCLUSION

This multicenter study demonstrates adherence to guideline-based treatment targets, underscoring the high standards maintained by neurological intensive care units. Our study offers valuable insights into adherence to guideline-based treatment targets for neurocritical care patients in Germany. To improve patient care and optimize therapeutic strategies in neurovascular diseases, further research is needed to examine the impact of these adherence parameters on long-term outcomes.

Premorbid Blood Pressure Control Modifies Risk of DWI Lesions With Acute Blood Pressure Reduction in Intracerebral Hemorrhage

BACKGROUND

Hypoperfusion due to blood pressure (BP) reduction is a potential mechanism of cerebral ischemia after intracerebral hemorrhage. However, prior evaluations of the relationship between BP reduction and ischemia have been conflicting. Untreated chronic hypertension is common in intracerebral hemorrhage and alters cerebral autoregulation. We hypothesized that the risk of diffusion-weighted imaging (DWI) hyperintensities from acute BP reduction is modified by premorbid BP control.

METHODS

Individuals enrolled in the ERICH study (Ethnic/Racial Variations of Intracerebral Hemorrhage) from 2010 to 2015 were categorized as untreated, treated, or nonhypertensive based on preintracerebral hemorrhage diagnosis and antihypertensive medication use. The percent reduction of systolic BP (SBP) was calculated between presentation and 24 hours from admission. The primary outcome was the presence of DWI lesions. Using logistic regression, we tested the association between chronic hypertension status, SBP reduction, and their interaction with DWI lesion presence.

RESULTS

From 3000 participants, 877 with available magnetic resonance imaging met inclusion (mean age, 60.5±13.3 years; 42.5% women). DWI lesions were detected in 25.9%. Untreated, treated, and no hypertension accounted for 32.6%, 47.9%, and 19.5% of cases, respectively. SBP reduction was not directly associated with DWI lesions; however, an interaction effect was observed between SBP reduction and chronic hypertension status (P=0.036). Nonhypertensive subjects demonstrated a linear risk of DWI lesion presence with greater SBP reduction, whereas untreated hypertension demonstrated a stable risk across a wide range of SBP reduction (P=0.023).

CONCLUSIONS

Premorbid BP control, especially untreated hypertension, may influence the relationship between DWI lesions and acute BP reduction after intracerebral hemorrhage.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT01202864.

Impact of Therapeutic Interventions on Cerebral Autoregulatory Function Following Severe Traumatic Brain Injury: A Secondary Analysis of the BOOST-II Study

BACKGROUND

The Brain Oxygen Optimization in Severe Traumatic Brain Injury Phase II randomized controlled trial used a tier-based management protocol based on brain tissue oxygen (PbtO2) and intracranial pressure (ICP) monitoring to reduce brain tissue hypoxia after severe traumatic brain injury. We performed a secondary analysis to explore the relationship between brain tissue hypoxia, blood pressure (BP), and interventions to improve cerebral perfusion pressure (CPP). We hypothesized that BP management below the lower limit of autoregulation would lead to cerebral hypoperfusion and brain tissue hypoxia that could be improved with hemodynamic augmentation.

METHODS

Of the 119 patients enrolled in the Brain Oxygen Optimization in Severe Traumatic Brain Injury Phase II trial, 55 patients had simultaneous recordings of arterial BP, ICP, and PbtO2. Autoregulatory function was measured by interrogating changes in ICP and PbtO2 in response to fluctuations in CPP using time-correlation analysis. The resulting autoregulatory indices (pressure reactivity index and oxygen reactivity index) were used to identify the "optimal" CPP and limits of autoregulation for each patient. Autoregulatory function and percent time with CPP outside personalized limits of autoregulation were calculated before, during, and after all interventions directed to optimize CPP.

RESULTS

Individualized limits of autoregulation were computed in 55 patients (mean age 38 years, mean monitoring time 92 h). We identified 35 episodes of brain tissue hypoxia (PbtO2 < 20 mm Hg) treated with CPP augmentation. Following each intervention, mean CPP increased from 73 ± 14 mm Hg to 79 ± 17 mm Hg (p = 0.15), and mean PbtO2 improved from 18.4 ± 5.6 mm Hg to 21.9 ± 5.6 mm Hg (p = 0.01), whereas autoregulatory function trended toward improvement (oxygen reactivity index 0.42 vs. 0.37, p = 0.14; pressure reactivity index 0.25 vs. 0.21, p = 0.2). Although optimal CPP and limits remained relatively unchanged, there was a significant decrease in the percent time with CPP below the lower limit of autoregulation in the 60 min after compared with before an intervention (11% vs. 23%, p = 0.05).

CONCLUSIONS

Our analysis suggests that brain tissue hypoxia is associated with cerebral hypoperfusion characterized by increased time with CPP below the lower limit of autoregulation. Interventions to increase CPP appear to improve autoregulation. Further studies are needed to validate the importance of autoregulation as a modifiable variable with the potential to improve outcomes.

Blood pressure management after endovascular thrombectomy: Insights of recent randomized controlled trials

BACKGROUND

The ideal blood pressure (BP) target in patients who undergo endovascular thrombectomy (EVT) with successful reperfusion is uncertain. Observational studies show that elevated BP during this period is associated with a higher risk of intracranial hemorrhage (ICH) and worse clinical outcomes. Several randomized controlled trials (RCTs) have explored whether intensive BP lowering improves clinical outcomes in these patients.

AIMS

This review aims to summarize the recent RCTs that compare intensive and conventional BP management strategies following EVT and discuss the innovative directions to improve.

RESULT

The recently published RCTs failed to demonstrate the benefit of intensive BP control on the functional outcome and decreasing the risk of ICH. The complex mechanism in cerebral blood flow regulation and the inappropriate BP range chosen in RCTs may be the reasons behind the inconsistent results between observational studies and RCTs. Individualized BP management, reducing BP variability, and multi-stage BP management should be paid more attention in future exploration.

CONCLUSION

Intensive BP target did not improve clinical outcomes after successful EVT as compared with a conventional BP target. Further research is required to identify the optimal BP management strategy after reperfusion.

Acute Ischemic Stroke in the Clinic and the Laboratory: Targets for Translational Research

Ischemic stroke research has enabled significant advancements in diagnosis, treatment, and management of this debilitating disease, yet challenges remain standing in the way of better patient prognoses. In this narrative review, a fictional case illustrates challenges and uncertainties that medical professionals still face - penumbra identification, lack of neuroprotective agents, side-effects of tissue plasminogen activator, dearth of molecular biomarkers, incomplete microvascular reperfusion or no-reflow, post-recanalization hyperperfusion, blood pressure management and procedural anesthetic effects. The current state of the field is broadly reviewed per topic, with the aim to introduce a broad audience (scientist and clinician alike) to recent successes in translational stroke research and pending scientific queries that are tractable for preclinical assessment. Opportunities for co-operation between clinical and experimental stroke experts are highlighted to increase the size and frequency of strides the field makes to improve our understanding of this disease and ways of treating it.

Temperature Control in the Era of Personalized Medicine: Knowledge Gaps, Research Priorities, and Future Directions

Hypoxic-ischemic brain injury (HIBI) is the leading cause of death and disability after cardiac arrest. To date, temperature control is the only intervention shown to improve neurologic outcomes in patients with HIBI. Despite robust preclinical evidence supporting hypothermia as neuroprotective therapy after cardiac arrest, there remains clinical equipoise regarding optimal core temperature, therapeutic window, and duration of therapy. Current guidelines recommend continuous temperature monitoring and active fever prevention for at least 72 h and additionally note insufficient evidence regarding temperature control targeting 32 °C-36 °C. However, population-based thresholds may be inadequate to support the metabolic demands of ischemic, reperfused, and dysregulated tissue. Promoting a more personalized approach with individualized targets has the potential to further improve outcomes. This review will analyze current knowledge and evidence, address research priorities, explore the components of high-quality temperature control, and define critical future steps that are needed to advance patient-centered care for cardiac arrest survivors.

Individual Patient Data Meta-Analysis of Dynamic Cerebral Autoregulation and Functional Outcome After Ischemic Stroke

BACKGROUND

The relationship between dynamic cerebral autoregulation (dCA) and functional outcome after acute ischemic stroke (AIS) is unclear. Previous studies are limited by small sample sizes and heterogeneity.

METHODS

We performed a 1-stage individual patient data meta-analysis to investigate associations between dCA and functional outcome after AIS. Participating centers were identified through a systematic search of the literature and direct invitation. We included centers with dCA data within 1 year of AIS in adults aged over 18 years, excluding intracerebral or subarachnoid hemorrhage. Data were obtained on phase, gain, coherence, and autoregulation index derived from transfer function analysis at low-frequency and very low-frequency bands. Cerebral blood velocity, arterial pressure, end-tidal carbon dioxide, heart rate, stroke severity and sub-type, and comorbidities were collected where available. Data were grouped into 4 time points after AIS: <24 hours, 24 to 72 hours, 4 to 7 days, and >3 months. The modified Rankin Scale assessed functional outcome at 3 months. Modified Rankin Scale was analyzed as both dichotomized (0 to 2 versus 3 to 6) and ordinal (modified Rankin Scale scores, 0-6) outcomes. Univariable and multivariable analyses were conducted to identify significant relationships between dCA parameters, comorbidities, and outcomes, for each time point using generalized linear (dichotomized outcome), or cumulative link (ordinal outcome) mixed models. The participating center was modeled as a random intercept to generate odds ratios with 95% CIs.

RESULTS

The sample included 384 individuals (35% women) from 7 centers, aged 66.3±13.7 years, with predominantly nonlacunar stroke (n=348, 69%). In the affected hemisphere, higher phase at very low-frequency predicted better outcome (dichotomized modified Rankin Scale) at <24 (crude odds ratios, 2.17 [95% CI, 1.47-3.19]; P<0.001) hours, 24-72 (crude odds ratios, 1.95 [95% CI, 1.21-3.13]; P=0.006) hours, and phase at low-frequency predicted outcome at 3 (crude odds ratios, 3.03 [95% CI, 1.10-8.33]; P=0.032) months. These results remained after covariate adjustment.

CONCLUSIONS

Greater transfer function analysis-derived phase was associated with improved functional outcome at 3 months after AIS. dCA parameters in the early phase of AIS may help to predict functional outcome.

Deviation From Personalized Blood Pressure Targets Correlates With Worse Outcome After Successful Recanalization

BACKGROUND

Personalized blood pressure (BP) management for patients with acute ischemic stroke after successful endovascular thrombectomy lacks evidence. We aimed to investigate whether the deviation of BP from cerebral autoregulation limits is associated with worse outcomes.

METHODS AND RESULTS

We determined autoregulation by measuring mean velocity index and calculated the percentage of time and the burden (defined as the time-BP area) with BP outside the autoregulatory limits of each subject within 48 hours after endovascular thrombectomy. In total, 91 patients with large vessel occlusion stroke who had achieved successful recanalization were prospectively enrolled between May 2020 and February 2022. The burden with BP outside the autoregulatory limits was associated with poor outcome (modified Rankin Scale score 3-6) at 90 days (adjusted odds ratio, 1.28 [95% CI, 1.03-1.59]). The percentage of time with BP out of the autoregulatory limits was correlated with early neurological deterioration (National Institute of Health Stroke Scale scores increased ≥2 at 7 days) (adjusted odds ratio, 1.38 [95% CI, 1.04-1.83]). The burden of BP that decreased below the autoregulatory lower limit was associated with significant infarct growth (volume of infarct growth >11.6 mL) at 7 days (adjusted odds ratio, 1.21 [95% CI, 1.01-1.44]). The percentage of time that BP exceeded the autoregulatory upper limit was associated with symptomatic intracranial hemorrhage within 48 hours (adjusted odds ratio, 1.55 [95% CI, 1.02-2.34]).

CONCLUSIONS

Both the percentage of time and the burden of BP that deviates from the autoregulation-preserved range are associated with unfavorable clinical outcomes. This study highlights the potential benefits of autoregulation-guided BP management strategy after successful recanalization.

Blood Pressure Variability in Acute Stroke: A Narrative Review

The management of blood pressure variability (BPV) in acute stroke presents a complex challenge with profound implications for patient outcomes. This narrative review examines the role of BPV across various stages of acute stroke care, highlighting its impact on treatment strategies and prognostic considerations. In the prehospital setting, while guidelines lack specific recommendations for BP management, emerging evidence suggests a potential link between BPV and outcomes. Among ischaemic stroke patients who are ineligible for reperfusion therapies, BPV independently influences functional outcomes, emphasising the need for individualised approaches to BP control. During intravenous thrombolysis and endovascular therapy, the intricate interplay between BP levels, recanalisation status, and BPV is evident. Striking a balance between aggressive BP lowering and avoiding hypoperfusion-related complications is essential. Intracerebral haemorrhage management is further complicated by BPV, which emerges as a predictor of mortality and disability, necessitating nuanced BP management strategies. Finally, among patients with acute subarachnoid haemorrhage, increased BPV may be correlated with a rebleeding risk and worse outcomes, emphasizing the need for BPV monitoring in this population. Integration of BPV assessment into clinical practice and research protocols is crucial for refining treatment strategies that are tailored to individual patient needs. Future studies should explore novel interventions targeting BPV modulation to optimise stroke care outcomes.

Association between blood pressure variability and outcomes after endovascular thrombectomy for acute ischemic stroke: An individual patient data meta-analysis

INTRODUCTION

Data on the association between blood pressure variability (BPV) after endovascular thrombectomy (EVT) for acute ischemic stroke (AIS) and outcomes are limited. We sought to identify whether BPV within the first 24 hours post EVT was associated with key stroke outcomes.

METHODS

We combined individual patient-data from five studies among AIS-patients who underwent EVT, that provided individual BP measurements after the end of the procedure. BPV was estimated as either systolic-BP (SBP) standard deviation (SD) or coefficient of variation (CV) over 24 h post-EVT. We used a logistic mixed-effects model to estimate the association [expressed as adjusted odds ratios (aOR)] between tertiles of BPV and outcomes of 90-day mortality, 90-day death or disability [modified Rankin Scale-score (mRS) > 2], 90-day functional impairment (⩾1-point increase across all mRS-scores), and symptomatic intracranial hemorrhage (sICH), adjusting for age, sex, stroke severity, co-morbidities, pretreatment with intravenous thrombolysis, successful recanalization, and mean SBP and diastolic-BP levels within the first 24 hours post EVT.

RESULTS

There were 2640 AIS-patients included in the analysis. The highest tertile of SBP-SD was associated with higher 90-day mortality (aOR:1.44;95% CI:1.08-1.92), 90-day death or disability (aOR:1.49;95% CI:1.18-1.89), and 90-day functional impairment (adjusted common OR:1.42;95% CI:1.18-1.72), but not with sICH (aOR:1.22;95% CI:0.76-1.98). Similarly, the highest tertile of SBP-CV was associated with higher 90-day mortality (aOR:1.33;95% CI:1.01-1.74), 90-day death or disability (aOR:1.50;95% CI:1.19-1.89), and 90-day functional impairment (adjusted common OR:1.38;95% CI:1.15-1.65), but not with sICH (aOR:1.33;95% CI:0.83-2.14).

CONCLUSIONS

BPV after EVT appears to be associated with higher mortality and disability, independently of mean BP levels within the first 24 h post EVT. BPV in the first 24 h may be a novel target to improve outcomes after EVT for AIS.

Association between impaired dynamic cerebral autoregulation and BBB disruption in reversible cerebral vasoconstriction syndrome

BACKGROUND

Half of the sufferers of reversible cerebral vasoconstriction syndrome (RCVS) exhibit imaging-proven blood-brain barrier disruption. The pathogenesis of blood-brain barrier disruption in RCVS remains unclear and mechanism-specific intervention is lacking. We speculated that cerebrovascular dysregulation might be associated with blood-brain barrier disruption in RCVS. Hence, we aimed to evaluate whether the dynamic cerebral autoregulation is altered in patients with RCVS and could be associated with blood-brain barrier disruption.

METHODS

A cross-sectional study was conducted from 2019 to 2021 at headache clinics of a national tertiary medical center. Dynamic cerebral autoregulation was evaluated in all participants. The capacity of the dynamic cerebral autoregulation to damp the systemic hemodynamic changes, i.e., phase shift and gain between the cerebral blood flow and blood pressure waveforms in the very-low- and low-frequency bands were calculated by transfer function analysis. The mean flow correlation index was also calculated. Patients with RCVS received 3-dimensional isotropic contrast-enhanced T2 fluid-attenuated inversion recovery imaging to visualize blood-brain barrier disruption.

RESULTS

Forty-five patients with RCVS (41.9 ± 9.8 years old, 29 females) and 45 matched healthy controls (41.4 ± 12.5 years old, 29 females) completed the study. Nineteen of the patients had blood-brain barrier disruption. Compared to healthy controls, patients with RCVS had poorer dynamic cerebral autoregulation, indicated by higher gain in very-low-frequency band (left: 1.6 ± 0.7, p = 0.001; right: 1.5 ± 0.7, p = 0.003; healthy controls: 1.1 ± 0.4) and higher mean flow correlation index (left: 0.39 ± 0.20, p = 0.040; right: 0.40 ± 0.18, p = 0.017; healthy controls: 0.31 ± 0.17). Moreover, patients with RCVS with blood-brain barrier disruption had worse dynamic cerebral autoregulation, as compared to those without blood-brain barrier disruption, by having less phase shift in very-low- and low-frequency bands, and higher mean flow correlation index.

CONCLUSIONS

Dysfunctional dynamic cerebral autoregulation was observed in patients with RCVS, particularly in those with blood-brain barrier disruption. These findings suggest that impaired cerebral autoregulation plays a pivotal role in RCVS pathophysiology and may be relevant to complications associated with blood-brain barrier disruption by impaired capacity of maintaining stable cerebral blood flow under fluctuating blood pressure.

A systematic review on the assessment of cerebral autoregulation in patients with Large Vessel Occlusion

As the majority of large vessel occlusion (LVO) patients are not treated with revascularization therapies or efficiently revascularized, complementary management strategies are needed. In this article we explore the importance of cerebral autoregulation (CA) assessment in the prediction and/or modification of infarct growth and hemorrhagic transformation. In patients with LVO, these are important factors that affect prognosis. A systematic search of the PubMed, EMBASE databases and a targeted Google search was conducted, resulting in the inclusion of 34 relevant articles. There is an agreement that CA is impaired in patients with LVO; several factors have been identified such as time course, revascularization status, laterality, disease subtype and location, some of which may be potentially modifiable and affect outcomes. The personalized CA assessment of these patients suggests potential for better understanding of the inter-individual variability. Further research is needed for the development of more accurate, noninvasive techniques for continuous monitoring and personalized thresholds for CA.

Reperfusion status and postoperative blood pressure in acute stroke patients after endovascular treatment

Background and purpose

An aggressive lowering of blood pressure (BP) could lead to neurological worsening, particularly of the area that has not been reperfused in acute stroke patients with large vessel occlusion (LVO). We sought to investigate the association of reperfusion status and BP course following mechanical thrombectomy (MT) with outcomes in LVO.

Materials and methods

Consecutive patients with LVO treated with MT between Jan 2020 to Jun 2021 were enrolled in a retrospective cohort study. Hourly systolic BP (SBP) and diastolic BP (DBP) were recorded for 72 h following MT and maximum SBP and DBP levels were identified. The Extended Thrombolysis in Cerebral Infarction (eTICI) scale was used to assess reperfusion extent. LVO patients were stratified in 2 groups based on reperfusion status: complete reperfusion (eTICI 3) and incomplete reperfusion (eTICI 2b/c). Three-month functional independence was defined as a modified Rankin Scale score of 0-2.

Results

A total of 263 acute ischemic stroke patients with LVO were retrospectively evaluated. Complete reperfusion was achieved in 210 patients (79.8%). Post-MT maximum SBP over 160 mmHg was significantly related to worse functional outcome (38.1% vs. 55.7%, p = 0.006), higher likelihood of in-hospital mortality and 3-month mortality (19.0% vs. 6.9%, p = 0.004, 27.4% vs. 14.3%, p = 0.012). No statistical correlation was found between reperfusion status and blood pressure level (p > 0.05). In patients with complete reperfusion, patients with an average BP 120-140 mmHg tends to have worse functional outcome compared with 100-120 mmHg (OR = 1.77, 95%CI: 0.97-3.23, p = 0.061).

Conclusion

High maximum SBP levels following MT are associated with an increased likelihood of 3-month functional dependence and mortality. An average BP of 100-120 mmHg tends to have better functional independence in completely reperfused patients. The effect of intensive BP control on incomplete reperfusion still warrants further investigations.

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.

Blood pressure variability and short-term outcomes after mechanical thrombectomy in patients with acute ischemic stroke

OBJECTIVES

There is limited data evaluating effects of post-mechanical thrombectomy (MT) blood pressure (BP) control on short-term clinical outcomes in acute ischemic stroke (AIS) patients with large vessel occlusion (LVO). We aim to investigate the association of BP variations, after MT, with stroke early outcomes.

MATERIALS AND METHODS

A retrospective study was conducted on AIS patients with LVO undergoing MT at a tertiary center over 3.5 years. Hourly BP data was recorded within the first 24- and 48-hours post-MT. BP variability was expressed as the interquartile range (IQR) of BP distribution. Short-term favorable outcome was defined as modified Rankin scale (mRS) 0-3, discharge to home or inpatient rehabilitation facility (IRF).

RESULTS

Of the 95 enrolled subjects, 37(38.9%) had favorable outcomes at discharge and 8 (8.4%) died. After adjustment for confounders, an increase in IQR of systolic blood pressure (SBP) within the first 24 hours after MT revealed a significant inverse association with favorable outcomes (OR 0.43, 95% CI [0.19, 0.96], p = 0.039). Increased median MAP within the first 24 hours after MT correlated with favorable outcomes (OR 1.75, 95% CI [1.09, 2.83], p = 0.021). Subgroup analysis redemonstrated significant inverse association between increased SBP IQR and favorable outcomes (OR 0.48, 95% CI [0.21, 0.97], p = 0.042) among patients with successful revascularization.

CONCLUSIONS

Post-MT high SBP variability was associated with worse short-term outcomes in AIS patients with LVO regardless of recanalization status. MAP values may be used as indicators for functional prognosis.

Post-ischemic hyperemia following endovascular therapy for acute stroke is associated with lesion growth

A substantial proportion of acute stroke patients fail to recover following successful endovascular therapy (EVT) and injury to the brain and vasculature secondary to reperfusion may be a contributor. Acute stroke patients were included with: i) large vessel occlusion of the anterior circulation, ii) successful recanalization, and iii) evaluable MRI early after EVT. Presence of hyperemia on MRI perfusion was assessed by consensus using a modified ASPECTS. Three different approaches were used to quantify relative cerebral blood flow (rCBF). Sixty-seven patients with median age of 66 [59-76], 57% female, met inclusion criteria. Hyperemia was present in 35/67 (52%) patients early post-EVT, in 32/65 (49%) patients at 24 hours, and in 19/48 (40%) patients at 5 days. There were no differences in incomplete reperfusion, HT, PH-2, HARM, severe HARM or symptomatic ICH rates between those with and without early post-EVT hyperemia. A strong association (R2 = 0.81, p < 0.001) was found between early post-EVT hyperemia (p = 0.027) and DWI volume at 24 hours after adjusting for DWI volume at 2 hours (p < 0.001) and incomplete reperfusion at 24 hours (p = 0.001). Early hyperemia is a potential marker for cerebrovascular injury and may help select patients for adjunctive therapy to prevent edema, reperfusion injury, and lesion growth.

Assessment of Cerebral Autoregulation Using Invasive and Noninvasive Methods of Intracranial Pressure Monitoring

BACKGROUND

Pulse amplitude index (PAx), a descriptor of cerebrovascular reactivity, correlates the changes of the pulse amplitude of the intracranial pressure (ICP) waveform (AMP) with changes in mean arterial pressure (MAP). AMP relies on cerebrovascular compliance, which is modulated by the state of the cerebrovascular reactivity. PAx can aid in prognostication after acute brain injuries as a tool for the assessment of cerebral autoregulation and could potentially tailor individual management; however, invasive measurements are required for its calculation. Our aim was to evaluate the relationship between noninvasive PAx (nPAx) derived from a novel noninvasive device for ICP monitoring and PAx derived from gold standard invasive methods.

METHODS

We retrospectively analyzed invasive ICP (external ventricular drain) and non-invasive ICP (nICP), via mechanical extensometer (Brain4Care Corp.). Invasive and non-invasive ICP waveform morphology data was collected in adult patients with brain injury with arterial blood pressure monitoring. The time series from all signals were first treated to remove movement artifacts. PAx and nPAx were calculated as the moving correlation coefficients of 10-s averages of AMP or non-invasive AMP (nAMP) and MAP. AMP/nAMP was determined by calculating the fundamental frequency amplitude of the ICP/nICP signal over a 10-s window, updated every 10-s. We then evaluated the relationship between invasive PAx and noninvasive nPAx using the methods of repeated-measures analysis to generate an estimate of the correlation coefficient and its 95% confidence interval (CI). The agreement between the two methods was assessed using the Bland-Altman test.

RESULTS

Twenty-four patients were identified. The median age was 53.5 years (interquartile range 40-70), and intracranial hemorrhage (84%) was the most common etiology. Twenty-one (87.5%) patients underwent mechanical ventilation, and 60% were sedated with a median Glasgow Coma Scale score of 8 (7-15). Mean PAx was 0.0296 ± 0.331, and nPAx was 0.0171 ± 0.332. The correlation between PAx and nPAx was strong (R = 0.70, p < 0.0005, 95% CI 0.687-0.717). Bland-Altman analysis showed excellent agreement, with a bias of - 0.018 (95% CI - 0.026 to - 0.01) and a localized regression trend line that did not deviate from 0.

CONCLUSIONS

PAx can be calculated by conventional and noninvasive ICP monitoring in a statistically significant evaluation with strong agreement. Further study of the applications of this clinical tool is warranted, with the goal of early therapeutic intervention to improve neurologic outcomes following acute brain injuries.

Precision Medicine in Neurocritical Care for Cerebrovascular Disease Cases

Scientific advances have informed many aspects of acute stroke care but have also highlighted the complexity and heterogeneity of cerebrovascular diseases. While practice guidelines are essential in supporting the clinical decision-making process, they may not capture the nuances of individual cases. Personalized stroke care in ICU has traditionally relied on integrating clinical examinations, neuroimaging studies, and physiologic monitoring to develop a treatment plan tailored to the individual patient. However, to realize the potential of precision medicine in stroke, we need advances and evidence in several critical areas, including data capture, clinical phenotyping, serum biomarker development, neuromonitoring, and physiology-based treatment targets. Mathematical tools are being developed to analyze the multitude of data and provide clinicians with real-time information and personalized treatment targets for the critical care management of patients with cerebrovascular diseases. This review summarizes research advances in these areas and outlines principles for translating precision medicine into clinical practice.

Evaluation of extent vs velocity of cortical venous filing in stroke outcome after endovascular thrombectomy

PURPOSE

Abnormal venous drainage may affect the prognosis of patients undergoing endovascular reperfusion therapy (ERT). Herein, time-resolved dynamic computed tomography arteriography (dCTA) was applied to evaluate the relationship between the velocity and extent of cortical venous filling (CVF), collateral status and outcomes.

METHODS

Thirty-five consecutive patients with acute anterior circulation occlusion who underwent ERT within 24 h of onset and successfully recanalized were enrolled. All patients underwent dCTA before ERT. Slow first or end of CVF was considered to occur when the time point of CVF appearance or disappearance on the affected side occurred after than that on the healthy side, whereas an equal CVF, a CVF reduced by ≤ 50%, or by > 50% on the affected side, were considered good, intermediate, and poor CVF extent, respectively.

RESULTS

Slow first CVF (29 patients, 82.8%), slow end of CVF (29, 85.7%), and intermediate extent of CVF (7, 20.0%) were not associated with collateral status or outcomes. Poor extent of CVF (6, 17.1%) was associated with poor collateral status, higher proportion of midline shift, larger final infarct volume, higher modified Rankin Scale (mRS) score at discharge, and higher proportion of in-hospital mortality. All patients with transtentorial herniation had poor extent of CVF, and those with poor CVF extent had an mRS score ≥ 3 at discharge.

CONCLUSION

Poor CVF extent, as assessed by dCTA, is a more accurate and specific marker than slow CVF to identify patients at high risk for poor outcomes after ERT.

Hemorrhagic Conversion of Acute Ischemic Stroke

Stroke is a leading cause of morbidity and mortality worldwide; a serious complication of ischemic stroke is hemorrhagic transformation. Current treatment of acute ischemic stroke includes endovascular thrombectomy and thrombolytic therapy. Both of these treatment options are linked with increased risks of hemorrhagic conversion. The diagnosis and timely management of patients with hemorrhagic conversion is critically important to patient outcomes. This review aims to discuss hemorrhagic conversion of acute ischemic stroke including discussion of the pathophysiology, review of risk factors, imaging considerations, and treatment of patients with hemorrhagic conversion.

Neuromonitoring in Children with Cerebrovascular Disorders

BACKGROUND

Cerebrovascular disorders are an important cause of morbidity and mortality in children. The acute care of a child with an ischemic or hemorrhagic stroke or cerebral sinus venous thrombosis focuses on stabilizing the patient, determining the cause of the insult, and preventing secondary injury. Here, we review the use of both invasive and noninvasive neuromonitoring modalities in the care of pediatric patients with arterial ischemic stroke, nontraumatic intracranial hemorrhage, and cerebral sinus venous thrombosis.

METHODS

Narrative review of the literature on neuromonitoring in children with cerebrovascular disorders.

RESULTS

Neuroimaging, near-infrared spectroscopy, transcranial Doppler ultrasonography, continuous and quantitative electroencephalography, invasive intracranial pressure monitoring, and multimodal neuromonitoring may augment the acute care of children with cerebrovascular disorders. Neuromonitoring can play an essential role in the early identification of evolving injury in the aftermath of arterial ischemic stroke, intracranial hemorrhage, or sinus venous thrombosis, including recurrent infarction or infarct expansion, new or recurrent hemorrhage, vasospasm and delayed cerebral ischemia, status epilepticus, and intracranial hypertension, among others, and this, is turn, can facilitate real-time adjustments to treatment plans.

CONCLUSIONS

Our understanding of pediatric cerebrovascular disorders has increased dramatically over the past several years, in part due to advances in the neuromonitoring modalities that allow us to better understand these conditions. We are now poised, as a field, to take advantage of advances in neuromonitoring capabilities to determine how best to manage and treat acute cerebrovascular disorders in children.

Contribution of intracranial pressure to human dynamic cerebral autoregulation after acute brain injury

Cerebral perfusion pressure (CPP) is normally expressed by the difference between mean arterial blood pressure (MAP) and intracranial pressure (ICP) but comparison of the separate contributions of MAP and ICP to human cerebral blood flow autoregulation has not been reported. In patients with acute brain injury (ABI), internal jugular vein compression (IJVC) was performed for 60 s. Dynamic cerebral autoregulation (dCA) was assessed in recordings of middle cerebral artery blood velocity (MCAv, transcranial Doppler), and invasive measurements of MAP and ICP. Patients were separated according to injury severity as having whole/undamaged skull, large fractures, or craniotomies, or following decompressive craniectomy. Glasgow coma score was not different for the three groups. IJVC induced changes in MCAv, MAP, ICP, and CPP in all three groups. The MCAv response to step changes in MAP and ICP expressed the dCA response to these two inputs and was quantified with the autoregulation index (ARI). In 85 patients, ARI was lower for the ICP input as compared with the MAP input (2.25 ± 2.46 vs. 3.39 ± 2.28; P < 0.0001), and particularly depressed in the decompressive craniectomy (DC) group (n = 24, 0.35 ± 0.62 vs. 2.21 ± 1.96; P < 0.0005). In patients with ABI, the dCA response to changes in ICP is less efficient than corresponding responses to MAP changes. These results should be taken into consideration in studies aimed to optimize dCA by manipulation of CPP in neurocritical patients.

The 2020 Taiwan Stroke Society guidelines for blood pressure control at the acute stage of ischemic stroke

The 2020 Taiwan Stroke Society (TSS) guidelines for blood pressure (BP) control related to ischemic stroke update the 2015 TSS BP guidelines. The early management of acute ischemic stroke has evolved rapidly in the previous two decades. Since the publication of the previous version of the TSS BP guidelines, many studies have addressed BP management in ischemic stroke. Particularly, several successful endovascular thrombectomy (EVT) trials published in 2015 led to a new era of acute treatment for ischemic stroke. With the ever-increasing use of EVT, evidence-based guidelines for ideal BP management during and after EVT are urgently needed. Consequently, the 2020 guidelines are updating and providing recommendations on BP control for the treatment and prevention of ischemic stroke based on new evidence. The present study encompasses the most important chapter of the 2020 Taiwan BP guidelines: BP control at the acute stage of ischemic stroke. We incorporated the most updated evidence regarding BP control at the acute stage of ischemic stroke in patients receiving or not receiving acute reperfusion therapy and provided specific recommendations for different treatment subgroups accordingly.

Neurofilament light is associated with clinical outcome and hemorrhagic transformation in moderate to severe ischemic stroke

Background

Ischemic stroke is a leading cause of morbidity and mortality worldwide. One possible predictor is the use of biomarkers especially neurofilament light chain (NFL).

Objectives

To explore whether NFL could predict clinical outcome and hemorrhagic transformation in moderate to severe stroke.

Design

Single center prospective cohort study.

Methods

Fifty-one moderate to severe ischemic stroke patients were recruited. Blood NFL was obtained from patients at admission (First sample) and 24-96 hours later (Second sample). NFL was analyzed with the ultrasensitive single molecule array (Simoa). Later, we calculated incremental rate NFL (IRN) by changes in NFL per day from baseline. We evaluated National Institute of Health stroke scale (NIHSS), modified Rankins score (mRs), and the presence of hemorrhagic transformation (HT).

Results

IRN was found to be higher in patients with unfavorable outcome (7.12 vs 24.07, P = .04) as well as Second sample (49.06 vs 71.41, P = .011), while NFL First sample was not significant. IRN had a great correlation with mRS (r = .552, P < .001). Univariate logistic regression model showed OR of IRN and Second sample to be 1.081 (95% CI 1.016-1.149, P = .013) and 1.019 (1.002-1.037, P = .03), respectively. Multiple logistic regression model has shown to be significant. In receiver operating analysis, IRN, Second sample, combined IRN with NIHSS and combined Second sample with NIHSS showed AUC (.744, P = .004; 0.713, P = .01; 0.805, P < .001; 0.803, P < .001, respectively). For HT, First sample and Second sample had significant difference with HT (Z = 2.13, P = .033; Z = 2.487, P = .013, respectively).

Conclusion

NFL was found to correlate and predict clinical outcome. In addition, it was found to correlate with HT.

Periprocedure Management of Blood Pressure After Acute Ischemic Stroke

The management of acute ischemic stroke primarily revolves around the timely restoration of blood flow (recanalization/reperfusion) in the occluded vessel and maintenance of cerebral perfusion through collaterals before reperfusion. Mechanical thrombectomy is the most effective treatment for acute ischemic stroke due to large vessel occlusions in appropriately selected patients. Judicious management of blood pressure before, during, and after mechanical thrombectomy is critical to ensure good outcomes by preventing progression of cerebral ischemia as well hemorrhagic conversion, in addition to optimizing systemic perfusion. While direct evidence to support specific hemodynamic targets around mechanical thrombectomy is limited, there is increasing interest in this area. Newer approaches to blood pressure management utilizing individualized cerebral autoregulation-based targets are being explored. Early efforts at utilizing machine learning to predict blood pressure treatment thresholds and therapies also seem promising; this focused review aims to provide an update on recent evidence around periprocedural blood pressure management after acute ischemic stroke, highlighting its implications for clinical practice while identifying gaps in current literature.

Poor Internal Jugular Venous Outflow Is Associated with Poor Cortical Venous Outflow and Outcomes after Successful Endovascular Reperfusion Therapy

Many patients show poor outcomes following endovascular reperfusion therapy (ERT), and poor cortical venous outflow is a risk factor for these poor outcomes. We investigated the association between the outflow of the internal jugular vein (IJV) and baseline cortical venous outflow and the outcomes after ERT. We retrospectively enrolled 78 patients diagnosed with an acute anterior circulation stroke and successful ERT. Poor IJV outflow on the affected side was defined as stenosis ≥50% or occlusion of ipsilateral IJV, and poor outflow of bilateral IJVs was defined as stenosis ≥50% or occlusion of both IJVs. Poor cortical venous outflow was defined as a cortical vein opacification score (COVES) of 0 on admission. Multivariate analysis showed that poor outflow of IJV on the affected side was an independent predictor for hemorrhagic transformation. The poor outflow of bilateral IJVs was an independent risk factor for poor clinical outcomes. These patients also had numerical trends of a higher incidence of symptomatic intracranial hemorrhage, midline shift >10 mm, and in-hospital mortality; however, statistical significance was not observed. Additionally, poor IJV outflow was an independent determinant of poor cortical venous outflow. For acute large vessel occlusion patients, poor IJV outflow is associated with poor baseline cortical venous outflow and outcomes after successful ERT.

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.

A Standardized Multimodal Neurological Monitoring Protocol-Guided Cerebral Protection Therapy for Venoarterial Extracorporeal Membrane Oxygenation Supported Patients

Background

The main objective of this study was to investigate the role of a multimodal neurological monitoring (MNM)-guided protocol in the precision identification of neural impairment and long-term neurological outcomes in venoarterial extracorporeal membrane oxygenation (VA-ECMO) supported patients.

Methods

We performed a cohort study that examined adult patients who underwent VA-ECMO support in our center between February 2010 and April 2021. These patients were retrospectively assigned to the “with MNM group” and the “without MNM group” based on the presence or absence of MNM-guided precision management. The differences in ECMO-related characteristics, evaluation indicators (precision, sensitivity, and specificity) of the MNM-guided protocol, and the long-term outcomes of the surviving patients were measured and compared between the two groups.

Results

A total of 63 patients with VA-ECMO support were retrospectively assigned to the without MNM group (n = 35) and the with MNM group (n = 28). The incidence of neural impairment in the without MNM group was significantly higher than that in the with MNM group (82.1 vs. 54.3%, P = 0.020). The MNM group exhibited older median ages [52.5 (39.5, 65.3) vs. 31 (26.5, 48.0), P = 0.008], a higher success rate of ECMO weaning (92.8 vs. 71.4%, P = 0.047), and a lower median duration of building ECMO [40.0 (35.0, 52.0) vs. 58.0 (48.0, 76.0), P = 0.025] and median ECMO duration days [5.0 (4.0, 6.2) vs. 7.0 (5.0, 10.5), P = 0.018] than the group without MNM. The MNM-guided protocol exhibited a higher precision rate (82.1 vs. 60.0%), sensitivity (95.7 vs. 78.9%), and specificity (83.3 vs. 37.5%) in identifying neural impairment in VA-ECMO support patients. There were significant differences in the long-term outcomes of survivors at 1, 3 and 6 months after discharge between the two groups (P < 0.05). However, the results showed no significant differences in ICU length of stay (LOS), hospital LOS, survival to discharge, or 28-day mortality between the two groups (P > 0.05).

Conclusion

The MNM-guided protocol is conducive to guiding intensivists in the improvement of cerebral protection therapy for ECMO-supported patients to detect and treat potential neurologic impairment promptly, and then improving long-term neurological outcomes after discharge.

Association of Blood Pressure Within 6 h After Endovascular Thrombectomy and Functional Outcomes in Ischemic Stroke Patients With Successful Recanalization

Background and Purpose

Blood pressure in the days following endovascular thrombectomy (EVT) can influence functional outcomes of patients who have suffered an acute ischemic stroke, but whether the same is true of blood pressure during the first few hours after EVT is unclear.

Methods

Several blood pressure parameters were retrospectively analyzed in acute ischemic stroke patients who underwent EVT at West China Hospital from March 2016 to December 2019. Baseline blood pressure, speed of blood pressure reduction, postoperative blood pressure, degree of blood pressure reduction, and quality of blood pressure management were evaluated during the first 24 h after EVT. We explored whether these parameters during different time windows correlated significantly with patients' modified Rankin Scale (mRS) score at 90 days.

Results

Analysis of 163 patients showed that poor functional outcome (mRS scores 3–6) correlated significantly with higher postoperative blood pressure and worse blood pressure management during the first 6 h after EVT. Postoperative systolic blood pressure at 37 min after EVT was significantly higher in patients with poor outcome (141 mmHg) than in those with good outcome (mRS scores 0–2; 122 mmHg, p = 0.006), and systolic pressure >136 mmHg at this time point was associated with a significantly higher risk of poor outcome, before and after adjusting for other risk factors (adjusted OR 0.395, 95% CI 0.20–0.79).

Conclusions

Among acute ischemic patients who successfully undergo recanalization, adequate blood pressure management during the first 30–40 min after EVT may be important for ensuring good 90-day functional outcomes.

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.

Blood Pressure Trajectory Groups and Outcome After Endovascular Thrombectomy: A Multicenter Study

BACKGROUND

Elevated blood pressure after endovascular thrombectomy (EVT) has been associated with an increased risk of hemorrhagic transformation and poor functional outcomes. However, the optimal hemodynamic management after EVT remains unknown, and the blood pressure course in the acute phase of ischemic stroke has not been well characterized. This study aimed to identify patient subgroups with distinct blood pressure trajectories after EVT and study their association with radiographic and functional outcomes.

METHODS

This multicenter retrospective cohort study included consecutive patients with anterior circulation large-vessel occlusion ischemic stroke who underwent EVT. Repeated time-stamped blood pressure data were recorded for the first 72 hours after thrombectomy. Latent variable mixture modeling was used to separate subjects into five groups with distinct postprocedural systolic blood pressure (SBP) trajectories. The primary outcome was functional status, measured on the modified Rankin Scale 90 days after stroke. Secondary outcomes included hemorrhagic transformation, symptomatic intracranial hemorrhage, and death.

RESULTS

Two thousand two hundred sixty-eight patients (mean age [±SD] 69±15, mean National Institutes of Health Stroke Scale 15±7) were included in the analysis. Five distinct SBP trajectories were observed: low (18%), moderate (37%), moderate-to-high (20%), high-to-moderate (18%), and high (6%). SBP trajectory group was independently associated with functional outcome at 90 days (P<0.0001) after adjusting for potential confounders. Patients with high and high-to-moderate SBP trajectories had significantly greater odds of an unfavorable outcome (adjusted odds ratio, 3.5 [95% CI, 1.8-6.7], P=0.0003 and adjusted odds ratio, 2.2 [95% CI, 1.5-3.2], P<0.0001, respectively). Subjects in the high-to-moderate group had an increased risk of symptomatic intracranial hemorrhage (adjusted odds ratio, 1.82 [95% CI, 1-3.2]; P=0.04). No significant association was found between trajectory group and hemorrhagic transformation.

CONCLUSIONS

Patients with acute ischemic stroke demonstrate distinct SBP trajectories during the first 72 hours after EVT that have differing associations with functional outcome. These findings may help identify potential candidates for future blood pressure modulation trials.

The intensive care management of acute ischaemic stroke

PURPOSE OF REVIEW

To discuss recent advances in the critical care management of acute ischaemic stroke patients and highlight controversies and consensus.

RECENT FINDINGS

Intravenous thrombolysis and endovascular thrombectomy are standard of care reperfusion therapies that have revolutionized the management of acute ischaemic stroke and transformed outcomes for patients. They can now be delivered in extended time windows and to those previously ineligible for intervention based on advanced neuroimaging criteria. Secondary systemic insults, such as hypo- and hypertension, hyperthermia or hyperglycaemia, which can extend the area of ischaemia must also be prevented or corrected to minimize infarct progression. Meticulous blood pressure management is of central importance, particularly in patients that have undergone reperfusion therapies. Neurological deterioration can occur because of infarct extension, haemorrhagic transformation or worsening cerebral oedema. Transcranial Doppler ultrasonography allows bedside, noninvasive evaluation of cerebral haemodynamics and is increasingly used in acute stroke triage, management and recovery prediction. The management of acute ischaemic stroke raises several ethical issues, and shared decision making is essential to ensure outcomes that are compatible with an individual patient's expectations.

SUMMARY

A bundle of medical, endovascular and surgical strategies implemented by a multidisciplinary team working to locally agreed protocols can improve long-term stroke outcomes.

Review of major trials of acute blood pressure management in stroke

Over the last two decades, there have been a number of major landmark clinical trials, classified as "major" as they sought to address clear clinical practice driven questions, in a pragmatic yet robust trial design, using a large powered sample size (n > 1000), in order to help improve patient outcome through informing guidelines. A commonality across all stroke sub-types included in these trials is the tendency to acute hypertensive crises within the acute stroke period. This phenomenon is associated with greater stroke complications and worsened overall prognosis. Multiple trials have attempted to address the issue of acute blood pressure management during the acute stroke period, with consideration for timing, magnitude of lowering, agent and relationship to other interventions. This review will consider the major clinical trials performed in ischaemic and haemorrhagic stroke that test the hypothesis that acute BP reduction improves clinical outcomes.

Review of studies on dynamic cerebral autoregulation in the acute phase of stroke and the relationship with clinical outcome

Acute stroke is associated with high morbidity and mortality. In the last decades, new therapies have been investigated with the aim of improving clinical outcomes in the acute phase post stroke onset. However, despite such advances, a large number of patients do not demonstrate improvement, furthermore, some unfortunately deteriorate. Thus, there is a need for additional treatments targeted to the individual patient. A potential therapeutic target is interventions to optimize cerebral perfusion guided by cerebral hemodynamic parameters such as dynamic cerebral autoregulation (dCA). This narrative led to the development of the INFOMATAS (Identifying New targets FOr Management And Therapy in Acute Stroke) project, designed to foster interventions directed towards understanding and improving hemodynamic aspects of the cerebral circulation in acute cerebrovascular disease states. This comprehensive review aims to summarize relevant studies on assessing dCA in patients suffering acute ischemic stroke, intracerebral haemorrhage, and subarachnoid haemorrhage. The review will provide to the reader the most consistent findings, the inconsistent findings which still need to be explored further and discuss the main limitations of these studies. This will allow for the creation of a research agenda for the use of bedside dCA information for prognostication and targeted perfusion interventions.

Integrative physiological assessment of cerebral hemodynamics and metabolism in acute ischemic stroke

Restoring perfusion to ischemic tissue is the primary goal of acute ischemic stroke care, yet only a small portion of patients receive reperfusion treatment. Since blood pressure (BP) is an important determinant of cerebral perfusion, effective BP management could facilitate reperfusion. But how BP should be managed in very early phase of ischemic stroke remains a contentious issue, due to the lack of clear evidence. Given the complex relationship between BP and cerebral blood flow (CBF)-termed cerebral autoregulation (CA)-bedside monitoring of cerebral perfusion and oxygenation could help guide BP management, thereby improve stroke patient outcome. The aim of INFOMATAS is to 'identify novel therapeutic targets for treatment and management in acute ischemic stroke'. In this review, we identify novel physiological parameters which could be used to guide BP management in acute stroke, and explore methodologies for monitoring them at the bedside. We outline the challenges in translating these potential prognostic markers into clinical use.

Effect of drug interventions on cerebral hemodynamics in ischemic stroke patients

The ischemic penumbra is sensitive to alterations in cerebral perfusion. A myriad of drugs are used in acute ischemic stroke (AIS) management, yet their impact on cerebral hemodynamics is poorly understood. As part of the Cerebral Autoregulation Network led INFOMATAS project (Identifying New Targets for Management and Therapy in Acute Stroke), this paper reviews some of the most common drugs a patient with AIS will come across and their potential influence on cerebral hemodynamics with a particular focus being on cerebral autoregulation (CA). We first discuss how compounds that promote clot lysis and prevent clot formation could potentially impact cerebral hemodynamics, before focusing on how the different classes of antihypertensive drugs can influence cerebral hemodynamics. We discuss the different properties of each drug and their potential impact on cerebral perfusion and CA. With emerging interest in CA status of AIS patients, either during or soon after treatment when timely reperfusion and salvageable tissue is at its most critical, the properties of these pharmacological agents may be relevant for modelling cerebral perfusion accuracy and for setting individualised treatment strategies.

Association between systolic blood pressure course and outcomes after stroke thrombectomy

Background

Systolic blood pressure (SBP) after endovascular thrombectomy (EVT) for large artery occlusive stroke is dynamic, requiring adaptable early prediction tools for improving outcomes. We investigated if post-EVT SBP course was associated with outcomes.

Methods

EVT-treated patients who had a stroke at Karolinska University Hospital, Stockholm, Sweden, were included in the study during 12 February 2018–11 February 2020. SBP was recorded during the first 24 hours after EVT. Primary outcome was functional independence defined by a Modified Rankin Scale score of 0–2 at 3 months. Secondary outcomes were death by 3 months, symptomatic intracranial haemorrhage and any intracranial haemorrhage. Patients with favourable outcomes were used as a reference SBP course in mixed linear effects models and compared with SBP courses of patients with unfavourable outcomes using the empirical best linear unbiased predictor, measuring deviations from the reference SBP course using the random effects. We tested model predictive stability for SBP measurements of only 18, 12 or 6 hours after EVT.

Results

374 patients were registered, with mean age 71, median NIHSS score of 15, and 53.2% men. Deviating from a linear SBP course starting at 130 mm Hg and decreasing to 123 mm Hg at 24 hours after EVT was associated with lower chances of functional independence (adjusted OR 0.53, 95% CI 0.29 to 0.88, for reaching either 99 or 147 mm Hg at 24 hours after EVT). All SBP course models for the remaining outcomes did not show statistical significance. Functional independence models showed stable predictive values for all time periods.

Conclusion

Deviating from a linear SBP course was associated with lower chances of 3-month functional independence.

Blood Pressure After Endovascular Thrombectomy and Outcomes in Patients With Acute Ischemic Stroke: An Individual Patient Data Meta-analysis

OBJECTIVE

To explore the association between blood pressure (BP) levels after endovascular thrombectomy (EVT) and the clinical outcomes of acute ischemic stroke (AIS) patients with large vessel occlusion (LVO).

METHODS

A study was eligible if it enrolled AIS patients older than 18 years, with an LVO treated with either successful or unsuccessful EVT, and provided either individual or mean 24-hour systolic BP values after the end of the EVT procedure. Individual patient data from all studies were analyzed using a generalized linear mixed-effects model.

RESULTS

A total of 5874 patients (mean age: 69±14 years, 50% women, median NIHSS on admission: 16) from 7 published studies were included. Increasing mean systolic BP levels per 10 mm Hg during the first 24 hours after the end of the EVT were associated with a lower odds of functional improvement (unadjusted common OR=0.82, 95%CI:0.80-0.85; adjusted common OR=0.88, 95%CI:0.84-0.93) and modified Ranking Scale score≤2 (unadjusted OR=0.82, 95%CI:0.79-0.85; adjusted OR=0.87, 95%CI:0.82-0.93), and a higher odds of all-cause mortality (unadjusted OR=1.18, 95%CI:1.13-1.24; adjusted OR=1.15, 95%CI:1.06-1.23) at 3 months. Higher 24-hour mean systolic BP levels were also associated with an increased likelihood of early neurological deterioration (unadjusted OR=1.14, 95%CI:1.07-1.21; adjusted OR=1.14, 95%CI:1.03-1.24) and a higher odds of symptomatic intracranial hemorrhage (unadjusted OR=1.20, 95%CI:1.09-1.29; adjusted OR=1.20, 95%CI:1.03-1.38) after EVT.

CONCLUSION

Increased mean systolic BP levels in the first 24 hours after EVT are independently associated with a higher odds of symptomatic intracranial hemorrhage, early neurological deterioration, three-month mortality, and worse three-month functional outcomes.