Intravenous Glibenclamide Reduces Lesional Water Uptake in Large Hemispheric Infarction

Association of Serum Macrophage Migration Inhibitory Factor with 3-Month Poor Outcome and Malignant Cerebral Edema in Patients with Large Hemispheric Infarction

BACKGROUND

We aimed to investigate the associations of macrophage migration inhibitory factor (MIF), toll-like receptors 2 and 4 (TLR2/4), and matrix metalloproteinase 9 (MMP9) with 3-month poor outcome, death, and malignant cerebral edema (MCE) in patients with large hemispheric infarction (LHI).

METHODS

Patients with LHI within 24 h of onset were enrolled consecutively. Serum MIF, TLR2/4, and MMP9 concentrations on admission were measured. Poor outcome was defined as a modified Rankin Scale score of ≥ 3 at 3 months. MCE was defined as a decreased level of consciousness, anisocoria and midline shift > 5 mm or basal cistern effacement, or indications for decompressive craniectomy during hospitalization. The cutoff values for MIF/MMP9 were obtained from the receiver operating characteristic curve.

RESULTS

Of the 130 patients with LHI enrolled, 90 patients (69.2%) had 3-month poor outcome, and MCE occurred in 55 patients (42.3%). Patients with serum MIF concentrations ≤ 7.82 ng/mL for predicting 3-month poor outcome [adjusted odds ratio (OR) 2.827, 95% confidence interval (CI) 1.144-6.990, p = 0.024] also distinguished death (adjusted OR 4.329, 95% CI 1.841-10.178, p = 0.001). Similarly, MMP9 concentrations ≤ 46.56 ng/mL for predicting 3-month poor outcome (adjusted OR 2.814, 95% CI 1.236-6.406, p = 0.014) also distinguished 3-month death (adjusted OR 3.845, 95% CI 1.534-9.637, p = 0.004).

CONCLUSIONS

Lower serum MIF and MMP9 concentrations at an early stage were independently associated with 3-month poor outcomes and death in patients with LHI. These findings need further confirmation in larger sample studies.

Prognostic Significance of Plasma VEGFA and VEGFR2 in Acute Ischemic Stroke-a Prospective Cohort Study

Enhancement of vascular remodeling in affected brain tissue is a novel therapy for acute ischemic stroke (AIS). However, conclusions regarding angiogenesis after AIS remain ambiguous. Vascular endothelial growth factor A (VEGFA) and VEGF receptor 2 (VEGFR2) are potent regulators of angiogenesis and vascular permeability. We aimed to investigate the association between VEGFA/VEGFR2 expression in the acute stage of stroke and prognosis of patients with AIS. We enrolled 120 patients with AIS within 24 h of stroke onset and 26 healthy controls. Plasma levels of VEGFA and VEGFR2 were measured by enzyme-linked immunosorbent assay (ELISA). The primary endpoint was an unfavorable outcome defined as a modified Rankin Scale (mRS) score > 2 at 3 months after AIS. Univariate and multivariate logistic regression analyses were used to identify risk factors affecting prognosis. Plasma VEGFA and VEGFR2 were significantly higher in patients with AIS than in health controls, and also significantly higher in patients with unfavorable than those with favorable outcomes. Moreover, both VEGFA and VEGFR2 showed a significantly positive correlation with mRS at 3 months. Univariate and multivariate analyses showed VEGFA and VEGFR2 remained associated with unfavorable outcomes, and adding VEGFA and VEGFR2 to the clinical model significantly improved risk reclassification (continuous net reclassification improvement, 105.71%; integrated discrimination improvement, 23.45%). The new risk model curve exhibited a good fit with an area under the receiver operating characteristic curve (ROC) curve of 0.9166 (0.8658-0.9674). Plasma VEGFA and VEGFR2 are potential markers for predicting prognosis; thus these two plasma biomarkers may improve risk stratification in patients with AIS.

Efficacy and Safety of Early Treatment with Glibenclamide in Patients with Aneurysmal Subarachnoid Hemorrhage: A Randomized Controlled Trial

BACKGROUND

This study aims to investigate the efficacy and safety of glibenclamide treatment in patients with acute aneurysmal subarachnoid hemorrhage (aSAH).

METHODS

The randomized controlled trial was conducted from October 2021 to May 2023 at two university-affiliated hospitals in Beijing, China. The study included patients with aSAH within 48 h of onset, of whom were divided into the intervention group and the control group according to the random number table method. Patients in the intervention group received glibenclamide tablet 3.75 mg/day for 7 days. The primary end points were the levels of serum neuron-specific enolase (NSE) and soluble protein 100B (S100B) between the two groups. Secondary end points included evaluating changes in the midline shift and the gray matter-white matter ratio, as well as assessing the modified Rankin Scale scores during follow-up. The trial was registered at ClinicalTrials.gov (identifier NCT05137678).

RESULTS

A total of 111 study participants completed the study. The median age was 55 years, and 52% were women. The mean admission Glasgow Coma Scale was 10, and 58% of the Hunt-Hess grades were no less than grade III. The baseline characteristics of the two groups were similar. On days 3 and 7, there were no statistically significant differences observed in serum NSE and S100B levels between the two groups (P > 0.05). The computer tomography (CT) values of gray matter and white matter in the basal ganglia were low on admission, indicating early brain edema. However, there were no significant differences found in midline shift and gray matter-white matter ratio (P > 0.05) between the two groups. More than half of the patients had a beneficial outcome (modified Rankin Scale scores 0-2), and there were no statistically significant differences between the two groups. The incidence of hypoglycemia in the two groups were 4% and 9%, respectively (P = 0.439).

CONCLUSIONS

Treating patients with early aSAH with oral glibenclamide did not decrease levels of serum NSE and S100B and did not improve the poor 90-day neurological outcome. In the intervention group, there was a visible decreasing trend in cases of delayed cerebral ischemia, but no statistically significant difference was observed. The incidence of hypoglycemia did not differ significantly between the two groups.

Enhanced Prediction of Malignant Cerebral Edema in Large Vessel Occlusion with Successful Recanalization Through Automated Weighted Net Water Uptake

BACKGROUND

Malignant cerebral edema (MCE) is associated with both net water uptake (NWU) and infarct volume. We hypothesized that NWU weighted by the affected Alberta Stroke Program Early Computed Tomography Score (ASPECTS) regions could serve as a quantitative imaging biomarker of aggravated edema development in acute ischemic stroke with large vessel occlusion (LVO). The aim of this study was to evaluate the performance of weighted NWU (wNWU) to predict MCE in patients with mechanical thrombectomy (MT).

METHODS

We retrospectively analyzed consecutive patients who underwent MT due to LVO. NWU was computed from nonenhanced computed tomography scans upon admission using automated ASPECTS software. wNWU was derived by multiplying NWU with the number of affected ASPECTS regions in the ischemic hemisphere. Predictors of MCE were assessed through multivariate logistic regression analysis and receiver operating characteristic curves.

RESULTS

NWU and wNWU were significantly higher in MCE patients than in non-MCE patients. Vessel recanalization status influenced the performance of wNWU in predicting MCE. In patients with successful recanalization, wNWU was an independent predictor of MCE (adjusted odds ratio 1.61; 95% confidence interval [CI] 1.24-2.09; P < 0.001). The model integrating wNWU, National Institutes of Health Stroke Scale, and collateral score exhibited an excellent performance in predicting MCE (area under the curve 0.80; 95% CI 0.75-0.84). Among patients with unsuccessful recanalization, wNWU did not influence the development of MCE (adjusted odds ratio 0.99; 95% CI 0.60-1.62; P = 0.953).

CONCLUSIONS

This study revealed that wNWU at admission can serve as a quantitative predictor of MCE in LVO with successful recanalization after MT and may contribute to the decision for early intervention.

Net water uptake as a predictive neuroimaging marker for acute ischemic stroke outcomes: a meta-analysis

OBJECTIVE

To assess the role of net water uptake (NWU) in predicting outcomes in acute ischemic stroke (AIS) patients.

METHODS

A systematic review and meta-analysis were performed, adhering to established guidelines. The search covered PubMed, Scopus, Web of Science, and Embase databases until July 1, 2023. Eligible studies reporting quantitative ischemic lesion NWU in admission CT scans of AIS patients, stratified based on outcomes, were included. Data analysis was performed using R software version 4.2.1.

RESULTS

Incorporating 17 original studies with 2217 AIS patients, NWU was significantly higher in patients with poor outcomes compared to those with good outcomes (difference of medians: 5.06, 95% CI: 3.00-7.13, p < 0.001). Despite excluding one outlier study, considerable heterogeneity persisted among the included studies (I2 = 90.8%). The meta-regression and subgroup meta-analyses demonstrated significantly higher NWU in patients with poor functional outcome, as assessed by modified Rankin Scale (difference of medians: 3.83, 95% CI: 1.98-5.68, p < 0.001, I2 = 72.9%), malignant edema/infarct (difference of medians: 8.30, 95% CI: 4.01-12.58, p < 0.001, I2 = 95.6%), and intracranial hemorrhage (difference of medians: 5.43, 95% CI: 0.44-10.43, p = 0.03, I2 = 91.1%).

CONCLUSION

NWU on admission CT scans shows promise as a predictive marker for outcomes in AIS patients. Prospective, multicenter trials with standardized, automated NWU measurement are crucial for robustly predicting diverse clinical outcomes.

CLINICAL RELEVANCE STATEMENT

The potential of net water uptake as a biomarker for predicting outcomes in acute ischemic stroke patients holds significant promise. Further validation through additional research could lead to its integration into clinical practice, potentially improving the accuracy of clinical decision-making and allowing for the development of more precise patient care strategies.

KEY POINTS

• Net water uptake, a CT-based biomarker, quantifies early brain edema after acute ischemic stroke. • Net water uptake is significantly higher in poor outcome acute ischemic stroke patients. • Net water uptake on CT scans holds promise in predicting diverse acute ischemic stroke outcomes.

Updates in Management of Large Hemispheric Infarct

This review delves into updates in management of large hemispheric infarction (LHI), a condition affecting up to 10% of patients with supratentorial strokes. While traditional management paradigms have endured, recent strides in research have revolutionized the approach to acute therapies, monitoring, and treatment. Notably, advancements in triage methodologies and the application of both pharmacological and mechanical abortive procedures have reshaped the acute care trajectory for patients with LHI. Moreover, ongoing endeavors have sought to refine strategies for the optimal surveillance and mitigation of complications, notably space-occupying mass effect, which can ensue in the aftermath of LHI. By amalgamating contemporary guidelines with cutting-edge clinical trial findings, this review offers a comprehensive exploration of the current landscape of acute and ongoing patient care for LHI, illuminating the evolving strategies that underpin effective management in this critical clinical domain.

Effect of short- versus long-term serum glucose levels on early ischemic water homeostasis and functional outcome in patients with large vessel occlusion stroke

BACKGROUND AND PURPOSE

In ischemic stroke, the impact of short- versus long-term blood glucose level (BGL) on early lesion pathophysiology and functional outcome has not been assessed. The purpose of this study was to directly compare the effect of long-term blood glucose (glycated hemoglobin [HbA1c]) versus serum BGL on early edema formation and functional outcome.

METHODS

Anterior circulation ischemic stroke patients who underwent mechanical thrombectomy after multimodal computed tomography (CT) on admission were analyzed. Endpoints were early ischemic cerebral edema, measured by quantitative net water uptake (NWU) on initial CT and functional independence at Day 90.

RESULTS

A total of 345 patients were included. Patients with functional independence had significantly lower baseline NWU (3.1% vs. 8.3%; p < 0.001) and lower BGL (113 vs. 123 mg/dL; p < 0.001) than those without functional independence, while HbA1c levels did not differ significantly (5.7% vs. 5.8%; p = 0.15). A significant association was found for NWU and BGL (ß = 0.02, 95% confidence interval [CI] 0.006-0.03; p = 0.002), but not for HbA1c and NWU (ß = -0.16, 95% CI -0.53-0.21; p = 0.39). Mediation analysis showed that 67% of the effect of BGL on functional outcome was mediated by early edema formation.

CONCLUSION

Aggravated early edema and worse functional outcome was associated with elevated short-term serum BGL, but not with HbA1c levels. Hence, the link between short-term BGL and early edema development might be used as a target for adjuvant therapy in patients with ischemic stroke.

Analysis of brain edema in RHAPSODY

BACKGROUND

Cerebral edema is a secondary complication of acute ischemic stroke, but its time course and imaging markers are not fully understood. Recently, net water uptake (NWU) has been proposed as a novel marker of edema.

AIMS

Studying the RHAPSODY trial cohort, we sought to characterize the time course of edema and test the hypothesis that NWU provides distinct information when added to traditional markers of cerebral edema after stroke by examining its association with other markers.

METHODS

A total of 65 patients had measurable supratentorial ischemic lesions. Patients underwent head computed tomography (CT), brain magnetic resonance imaging (MRI) scans, or both at the baseline visit and after 2, 7, 30, and 90 days following enrollment. CT and MRI scans were used to measure four imaging markers of edema: midline shift (MLS), hemisphere volume ratio (HVR), cerebrospinal fluid (CSF) volume, and NWU using semi-quantitative threshold analysis. Trajectories of the markers were summarized, as available. Correlations of the markers of edema were computed and the markers compared by clinical outcome. Regression models were used to examine the effect of 3K3A-activated protein C (APC) treatment.

RESULTS

Two measures of mass effect, MLS and HVR, could be measured on all imaging modalities, and had values available across all time points. Accordingly, mass effect reached a maximum level by day 7, normalized by day 30, and then reversed by day 90 for both measures. In the first 2 days after stroke, the change in CSF volume was associated with MLS (ρ = -0.57, p = 0.0001) and HVR (ρ = -0.66, p < 0.0001). In contrast, the change in NWU was not associated with the other imaging markers (all p ⩾ 0.49). While being directionally consistent, we did not observe a difference in the edema markers by clinical outcome. In addition, baseline stroke volume was associated with all markers (MLS (p < 0.001), HVR (p < 0.001), change in CSF volume (p = 0.003)) with the exception of NWU (p = 0.5). Exploratory analysis did not reveal a difference in cerebral edema markers by treatment arm.

CONCLUSIONS

Existing cerebral edema imaging markers potentially describe two distinct processes, including lesional water concentration (i.e. NWU) and mass effect (MLS, HVR, and CSF volume). These two types of imaging markers may represent distinct aspects of cerebral edema, which could be useful for future trials targeting this process.

Imaging biomarkers of cerebral edema automatically extracted from routine CT scans of large vessel occlusion strokes

BACKGROUND AND PURPOSE

Volumetric and densitometric biomarkers have been proposed to better quantify cerebral edema after stroke, but their relative performance has not been rigorously evaluated.

METHODS

Patients with large vessel occlusion stroke from three institutions were analyzed. An automated pipeline extracted brain, cerebrospinal fluid (CSF), and infarct volumes from serial CTs. Several biomarkers were measured: change in global CSF volume from baseline (ΔCSF); ratio of CSF volumes between hemispheres (CSF ratio); and relative density of infarct region compared with mirrored contralateral region (net water uptake [NWU]). These were compared to radiographic standards, midline shift and relative hemispheric volume (RHV) and malignant edema, defined as deterioration resulting in need for osmotic therapy, decompressive surgery, or death.

RESULTS

We analyzed 255 patients with 210 baseline CTs, 255 24-hour CTs, and 81 72-hour CTs. Of these, 35 (14%) developed malignant edema and 63 (27%) midline shift. CSF metrics could be calculated for 310 (92%), while NWU could only be obtained from 193 (57%). Peak midline shift was correlated with baseline CSF ratio (ρ = -.22) and with CSF ratio and ΔCSF at 24 hours (ρ = -.55/.63) and 72 hours (ρ = -.66/.69), but not with NWU (ρ = .15/.25). Similarly, CSF ratio was correlated with RHV (ρ = -.69/-.78), while NWU was not. Adjusting for age, National Institutes of Health Stroke Scale, tissue plasminogen activator treatment, and Alberta Stroke Program Early CT Score, CSF ratio (odds ratio [OR]: 1.95 per 0.1, 95% confidence interval [CI]: 1.52-2.59) and ΔCSF at 24 hours (OR: 1.87 per 10%, 95% CI: 1.47-2.49) were associated with malignant edema.

CONCLUSION

CSF volumetric biomarkers can be automatically measured from almost all routine CTs and correlate better with standard edema endpoints than net water uptake.

Cation flux through SUR1-TRPM4 and NCX1 in astrocyte endfeet induces water influx through AQP4 and brain swelling after ischemic stroke

Brain swelling causes morbidity and mortality in various brain injuries and diseases but lacks effective treatments. Brain swelling is linked to the influx of water into perivascular astrocytes through channels called aquaporins. Water accumulation in astrocytes increases their volume, which contributes to brain swelling. Using a mouse model of severe ischemic stroke, we identified a potentially targetable mechanism that promoted the cell surface localization of aquaporin 4 (AQP4) in perivascular astrocytic endfeet, which completely ensheathe the brain's capillaries. Cerebral ischemia increased the abundance of the heteromeric cation channel SUR1-TRPM4 and of the Na⁺/Ca²⁺ exchanger NCX1 in the endfeet of perivascular astrocytes. The influx of Na⁺ through SUR1-TRPM4 induced Ca²⁺ transport into cells through NCX1 operating in reverse mode, thus raising the intra-endfoot concentration of Ca²⁺. This increase in Ca²⁺ stimulated calmodulin-dependent translocation of AQP4 to the plasma membrane and water influx, which led to cellular edema and brain swelling. Pharmacological inhibition or astrocyte-specific deletion of SUR1-TRPM4 or NCX1 reduced brain swelling and improved neurological function in mice to a similar extent as an AQP4 inhibitor and was independent of infarct size. Thus, channels in astrocyte endfeet could be targeted to reduce postischemic brain swelling in stroke patients.

Diabetic vascular diseases: molecular mechanisms and therapeutic strategies

Vascular complications of diabetes pose a severe threat to human health. Prevention and treatment protocols based on a single vascular complication are no longer suitable for the long-term management of patients with diabetes. Diabetic panvascular disease (DPD) is a clinical syndrome in which vessels of various sizes, including macrovessels and microvessels in the cardiac, cerebral, renal, ophthalmic, and peripheral systems of patients with diabetes, develop atherosclerosis as a common pathology. Pathological manifestations of DPDs usually manifest macrovascular atherosclerosis, as well as microvascular endothelial function impairment, basement membrane thickening, and microthrombosis. Cardiac, cerebral, and peripheral microangiopathy coexist with microangiopathy, while renal and retinal are predominantly microangiopathic. The following associations exist between DPDs: numerous similar molecular mechanisms, and risk-predictive relationships between diseases. Aggressive glycemic control combined with early comprehensive vascular intervention is the key to prevention and treatment. In addition to the widely recommended metformin, glucagon-like peptide-1 agonist, and sodium-glucose cotransporter-2 inhibitors, for the latest molecular mechanisms, aldose reductase inhibitors, peroxisome proliferator-activated receptor-γ agonizts, glucokinases agonizts, mitochondrial energy modulators, etc. are under active development. DPDs are proposed for patients to obtain more systematic clinical care requires a comprehensive diabetes care center focusing on panvascular diseases. This would leverage the advantages of a cross-disciplinary approach to achieve better integration of the pathogenesis and therapeutic evidence. Such a strategy would confer more clinical benefits to patients and promote the comprehensive development of DPD as a discipline.

Ischemic brain edema: Emerging cellular mechanisms and therapeutic approaches

Brain edema is one of the most devastating consequences of ischemic stroke. Malignant cerebral edema is the main reason accounting for the high mortality rate of large hemispheric strokes. Despite decades of tremendous efforts to elucidate mechanisms underlying the formation of ischemic brain edema and search for therapeutic targets, current treatments for ischemic brain edema remain largely symptom-relieving rather than aiming to stop the formation and progression of edema. Recent preclinical research reveals novel cellular mechanisms underlying edema formation after brain ischemia and reperfusion. Advancement in neuroimaging techniques also offers opportunities for early diagnosis and prediction of malignant brain edema in stroke patients to rapidly adopt life-saving surgical interventions. As reperfusion therapies become increasingly used in clinical practice, understanding how therapeutic reperfusion influences the formation of cerebral edema after ischemic stroke is critical for decision-making and post-reperfusion management. In this review, we summarize these research advances in the past decade on the cellular mechanisms, and evaluation, prediction, and intervention of ischemic brain edema in clinical settings, aiming to provide insight into future preclinical and clinical research on the diagnosis and treatment of brain edema after stroke.

Association Between Net Water Uptake and Functional Outcome in Patients With Low ASPECTS Brain Lesions: Results From the I-LAST Study

BACKGROUND AND OBJECTIVES

The effect of mechanical thrombectomy (MT) on functional outcome in patients with ischemic stroke with low ASPECTS is still uncertain. ASPECTS rating is based on the presence of ischemic hypoattenuation relative to normal; however, the degree of hypoattenuation, which directly reflects net uptake of water, is currently not considered an imaging biomarker in stroke triage. We hypothesized that the effect of thrombectomy on functional outcome in low ASPECTS patients depends on early lesion water uptake.

METHODS

For this multicenter observational study, patients with anterior circulation stroke with ASPECTS ≤5 were consecutively analyzed. Net water uptake (NWU) was assessed as a quantitative imaging biomarker in admission CT. The primary end point was the rate of favorable functional outcome defined as modified Rankin Scale score 0-3 at day 90. The effect of recanalization on functional outcome was analyzed according to the degree of NWU within the early infarct lesion.

RESULTS

A total of 254 patients were included, of which 148 (58%) underwent MT. The median ASPECTS was 4 (interquartile range [IQR] 3-5), and the median NWU was 11.4% (IQR 8.9%-15.1%). The rate of favorable outcome was 27.6% in patients with low NWU (<11.4%) vs 6.3% in patients with high NWU (≥11.4%; p < 0.0001). In multivariable logistic regression analysis, NWU was an independent predictor of outcome, whereas vessel recanalization (modified thrombolysis in cerebral infarction ≥2b) was only significantly associated with better outcomes if NWU was lower than 12.6%. In inverse-probability weighting analysis, recanalization was associated with 20.7% (p = 0.01) increase in favorable outcome in patients with low NWU compared with 9.1% (p = 0.06) in patients with high NWU.

DISCUSSION

Early NWU was independently associated with clinical outcome and might serve as an indicator of futile MT in low ASPECTS patients. NWU could be tested as a tool to select low ASPECTS patients for MT.

TRIAL REGISTRATION INFORMATION

The study is registered within the ClinicalTrials.gov Protocol Registration and Results System (NCT04862507).

Medical management of cerebral edema in large hemispheric infarcts

Acute ischemic stroke confers a high burden of morbidity and mortality globally. Occlusion of large vessels of the anterior circulation, namely the intracranial carotid artery and middle cerebral artery, can result in large hemispheric stroke in ~8% of these patients. Edema from stroke can result in a cascade effect leading to local compression of capillary perfusion, increased stroke burden, elevated intracranial pressure, herniation and death. Mortality from large hemispheric stroke is generally high and surgical intervention may reduce mortality and improve good outcomes in select patients. For those patients who are not eligible candidates for surgical decompression either due timing, medical co-morbidities, or patient and family preferences, the mainstay of medical management for cerebral edema is hyperosmolar therapy. Other neuroprotectants for cerebral edema such as glibenclamide are under investigation. This review will discuss current guidelines and evidence for medical management of cerebral edema in large hemispheric stroke as well as discuss important neuromonitoring and critical care management targeted at reducing morbidity and mortality for these patients.

Cerebral edema after ischemic stroke: Pathophysiology and underlying mechanisms

Ischemic stroke is associated with increasing morbidity and has become the main cause of death and disability worldwide. Cerebral edema is a serious complication arising from ischemic stroke. It causes an increase in intracranial pressure, rapid deterioration of neurological symptoms, and formation of cerebral hernia, and is an important risk factor for adverse outcomes after stroke. To date, the detailed mechanism of cerebral edema after stroke remains unclear. This limits advances in prevention and treatment strategies as well as drug development. This review discusses the classification and pathological characteristics of cerebral edema, the possible relationship of the development of cerebral edema after ischemic stroke with aquaporin 4, the SUR1-TRPM4 channel, matrix metalloproteinase 9, microRNA, cerebral venous reflux, inflammatory reactions, and cerebral ischemia/reperfusion injury. It also summarizes research on new therapeutic drugs for post-stroke cerebral edema. Thus, this review provides a reference for further studies and for clinical treatment of cerebral edema after ischemic stroke.

Automated Measurement of Net Water Uptake From Baseline and Follow-Up CTs in Patients With Large Vessel Occlusion Stroke

Quantifying the extent and evolution of cerebral edema developing after stroke is an important but challenging goal. Lesional net water uptake (NWU) is a promising CT-based biomarker of edema, but its measurement requires manually delineating infarcted tissue and mirrored regions in the contralateral hemisphere. We implement an imaging pipeline capable of automatically segmenting the infarct region and calculating NWU from both baseline and follow-up CTs of large-vessel occlusion (LVO) patients. Infarct core is extracted from CT perfusion images using a deconvolution algorithm while infarcts on follow-up CTs were segmented from non-contrast CT (NCCT) using a deep-learning algorithm. These infarct masks were flipped along the brain midline to generate mirrored regions in the contralateral hemisphere of NCCT; NWU was calculated as one minus the ratio of densities between regions, removing voxels segmented as CSF and with HU outside thresholds of 20-80 (normal hemisphere and baseline CT) and 0-40 (infarct region on follow-up). Automated results were compared with those obtained using manually-drawn infarcts and an ASPECTS region-of-interest based method that samples densities within the infarct and normal hemisphere, using intraclass correlation coefficient (ρ). This was tested on serial CTs from 55 patients with anterior circulation LVO (including 66 follow-up CTs). Baseline NWU using automated core was 4.3% (IQR 2.6-7.3) and correlated with manual measurement (ρ = 0.80, p < 0.0001) and ASPECTS (r = -0.60, p = 0.0001). Automatically segmented infarct volumes (median 110-ml) correlated to manually-drawn volumes (ρ = 0.96, p < 0.0001) with median Dice similarity coefficient of 0.83 (IQR 0.72-0.90). Automated NWU was 24.6% (IQR 20-27) and highly correlated to NWU from manually-drawn infarcts (ρ = 0.98) and the sampling-based method (ρ = 0.68, both p < 0.0001). We conclude that this automated imaging pipeline is able to accurately quantify region of infarction and NWU from serial CTs and could be leveraged to study the evolution and impact of edema in large cohorts of stroke patients.

Hypoxanthine is a pharmacodynamic marker of ischemic brain edema modified by glibenclamide

Brain edema after a large stroke causes significant morbidity and mortality. Here, we seek to identify pharmacodynamic markers of edema that are modified by intravenous (i.v.) glibenclamide (glyburide; BIIB093) treatment. Using metabolomic profiling of 399 plasma samples from patients enrolled in the phase 2 Glyburide Advantage in Malignant Edema and Stroke (GAMES)-RP trial, 152 analytes are measured using liquid chromatography-tandem mass spectrometry. Associations with midline shift (MLS) and the matrix metalloproteinase-9 (MMP-9) level that are further modified by glibenclamide treatment are compared with placebo. Hypoxanthine is the only measured metabolite that associates with MLS and MMP-9. In sensitivity analyses, greater hypoxanthine levels also associate with increased net water uptake (NWU), as measured on serial head computed tomography (CT) scans. Finally, we find that treatment with i.v. glibenclamide reduces plasma hypoxanthine levels across all post-treatment time points. Hypoxanthine, which has been previously linked to inflammation, is a biomarker of brain edema and a treatment response marker of i.v. glibenclamide treatment.

Correlation Between Computed Tomography-Based Tissue Net Water Uptake and Volumetric Measures of Cerebral Edema After Reperfusion Therapy

BACKGROUND

Cerebral edema after large hemispheric infarction is associated with poor functional outcome and mortality. Net water uptake (NWU) quantifies the degree of hypoattenuation on unenhanced-computed tomography (CT) and is increasingly used to measure cerebral edema in stroke research. Hemorrhagic transformation and parenchymal contrast staining after thrombectomy may confound NWU measurements. We investigated the correlation of NWU measured postthrombectomy with volumetric markers of cerebral edema and association with functional outcomes.

METHODS

In a pooled individual patient level analysis of patients presenting with anterior circulation large hemispheric infarction (core 80-300 mL or Alberta Stroke Program Early CT Score ≤5) in the HERMES (Highly Effective Reperfusion Evaluated in Multiple Endovascular Stroke trials) data set, cerebral edema was defined as the volumetric expansion of the ischemic hemisphere expressed as a ratio to the contralateral hemisphere(rHV). NWU and midline-shift were compared with rHV as the reference standard on 24-hour follow-up CT, adjusted for hemorrhagic transformation and the use of thrombectomy. Association between edema markers and day 90 functional outcomes (modified Rankin Scale) was assessed using ordinal logistic regression.

RESULTS

Overall (n=144), there was no correlation between NWU and rHV (r_s=0.055, P=0.51). In sub-group analyses, a weak correlation between NWU with rHV was observed after excluding patients with any degree of hemorrhagic transformation (r_s=0.211, P=0.015), which further improved after excluding thrombectomy patients (r_s=0.453, P=0.001). Midline-shift correlated strongly with rHV in all sub-group analyses (r_s>0.753, P=0.001). Functional outcome at 90 days was negatively associated with rHV (adjusted common odds ratio, 0.46 [95% CI, 0.32-0.65]; P<0.001) and midline-shift (adjusted common odds ratio, 0.85 [95% CI, 0.78-0.92]; P<0.001) but not NWU (adjusted common odds ratio, 1.00 [95% CI, 0.97-1.03]; P=0.84), adjusted for age, baseline National Institutes of Health Stroke Scale, and thrombectomy. Prognostic performance of NWU improved after excluding patients with hemorrhagic transformation and thrombectomy (adjusted odds ratio, 0.90 [95% CI, 0.80-1.02]; P=0.10).

CONCLUSIONS

NWU correlated poorly with conventional markers of cerebral edema and was not associated with clinical outcome in the presence of hemorrhagic transformation and thrombectomy. Measuring NWU postthrombectomy requires validation before implementation into clinical research. At present, the use of NWU should be limited to baseline CT, or follow-up CT only in patients without hemorrhagic transformation or treatment with thrombectomy.

Midline Shift Greater than 3 mm Independently Predicts Outcome After Ischemic Stroke

BACKGROUND

Cerebral edema is associated with worse outcome after acute stroke; however, the minimum clinically relevant threshold remains unknown. This study aimed to identify the minimal degree of midline shift (MLS) that predicts outcome in a cohort encompassing a broad range of patients with acute stroke.

METHODS

Patient-level data from six acute stroke clinical trials were combined with endovascular thrombectomy registries from two academic referral centers, generating a combined cohort of 1977 patients. MLS was extracted from the original trial data or measured on computed tomography or magnetic resonance imaging that was obtained a median of 47.0 h (interquartile range 27.0-75.1 h) after stroke onset. Logistic regression was performed to identify predictors of poor outcome and the minimal clinically relevant MLS threshold.

RESULTS

The presence of MLS was a predictor of poor outcome, independent of baseline clinical and demographic factors (adjusted odds ratio 4.46, 95% confidence interval 3.56-5.59, p < 0.001). Examining the full range of MLS values identified, a value of greater than 3 mm was the critical threshold that significantly predicted poor outcome (adjusted odds ratio 3.20 [1.31-7.82], p = 0.011).

CONCLUSIONS

These results show that the presence of MLS predicts poor outcome and, specifically, MLS value greater than 3 mm is an important threshold across a variety of clinical settings. These findings may have relevance for the design and interpretation of future trials for antiedema therapies.

Type 2 Diabetes Increases Risk of Unfavorable Survival Outcome for Postoperative Ischemic Stroke in Patients Who Underwent Non-cardiac Surgery: A Retrospective Cohort Study

Objective: Diabetes mellitus (DM) has been critically associated with unfavorable outcomes in the general population. We aimed to investigate the association between type 2 DM and long-term survival outcomes for postoperative ischemic stroke in patients who underwent non-cardiac surgery. Research Design and Methods: This was a retrospective cohort study of patients with non-cardiac surgery who had suffered from postoperative ischemic stroke between January 2008 and August 2019. Diabetic individuals were included in postoperative ischemic stroke patients with the DM group. The outcome of interest was long-term overall survival (OS). We conducted propensity score matching (PSM) and inverse probability treatment weighting (IPTW) to adjust for baseline characteristic differences between groups. Multivariate Cox regression analysis with stepwise selection was used to calculate the adjusted hazard ratio (HR) of OS and type 2 DM. Results: During a median follow-up of 46.2 month [interquartile range (IQR), 21.1, 84.2], 200 of 408 patients (49.0%) died. The OS rates at 3, 5, and 10 years were significantly lower for postoperative ischemic stroke patients with DM than those without DM (3 years OS: 52.2 vs. 69.5%, p < 0.001; 5 years OS: 41.6 vs. 62.4%, p < 0.001; 10 years OS: 37.2 vs. 56.6%, p < 0.001). All covariates were between-group balanced after using PSM or IPTW. The postoperative ischemic stroke patients with type 2 DM had a shortened OS in primary analysis (HR: 1.947; 95% CI: 1.397-2.713; p < 0.001), PSM analysis (HR: 2.190; 95% CI: 1.354-3.540; p = 0.001), and IPTW analysis (HR: 2.551; 95% CI: 1.769-3.679; p < 0.001). Conclusion: Type 2 DM was associated with an unfavorable survival outcome for postoperative ischemic stroke in patients who underwent non-cardiac surgery. When postoperative ischemic stroke co-occurred with type 2 DM, the potential synergies would have multiplicative mortality risk. Further research to assess the adverse effects of type 2 DM on long-term survival may be warranted.

Automated quantitative lesion water uptake in acute stroke is a predictor of malignant cerebral edema

OBJECTIVES

Net water uptake (NWU) has been shown to have a linear relationship with brain edema. Based on an automated-Alberta Stroke Program Early Computed Tomography Score (ASPECTS) technique, we automatically derived NWU from baseline multimodal computed tomography (CT), namely ASPECTS-NWU. We aimed to determine if ASPECTS-NWU can predict the development of malignant cerebral edema (MCE).

METHODS

One hundred and forty-six patients with large-vessel occlusion were retrospectively enrolled. Quantitative NWU based on automated-ASPECTS was measured both on nonenhanced CT (NECT) and CT angiography (CTA), namely NECT-ASPECT-NWU and CTA-ASPECTS-NWU. The correlation between ASPECTS-NWU and cerebral edema (CED) grades was calculated using Spearman rank correlation. Univariate logistic regression was used to assess the effect of radiological and clinical features on MCE, and a multivariable model with significant factors from the univariate regression analysis was built. Receiver operating characteristic (ROC) was obtained and area under curve (AUC) was compared.

RESULTS

CTA-ASPECTS-NWU had a moderate positive correlation with CED grades (r = 0.62; 95% confidence interval [CI], 0.51-0.71; p < 0.001). The CTA-ASPECTS-NWU performed better than the NECT-ASPECTS-NWU with AUC: 0.88 vs. 0.71 (p < 0.001). Multivariable logistic regression model integrating CTA-ASPECTS-NWU, collateral score, and age showed the CTA-ASPECTS-NWU was an independent predictor of MCE with an AUC of 0.94 (95% CI: 0.90-0.98; p < 0.001).

CONCLUSIONS

This study demonstrates that ASPECTS-NWU is a quantitative predictor of MCE after large-vessel occlusion of the middle cerebral artery territory. The multivariable logistic regression model may enhance the identification of patients with MCE needing anti-edematous treatment.

KEY POINTS

• The automated-ASPECTS technique can automatically detect the affected regions with early ischemic changes and NWU could be manually calculated. • The CTA-ASPECTS-NWU performs better than the NECT-ASPECTS-NWU on predicting the development of MCE. • The multivariable logistic regression model may enhance the identification of patients with MCE needing anti-edematous treatment.

Corrigendum: Type 2 diabetes increases risk of unfavorable survival outcome for postoperative ischemic stroke in patients who underwent non-cardiac surgery: A retrospective cohort study

[This corrects the article DOI: 10.3389/fnagi.2021.810050.].

Emerging therapeutic targets for cerebral edema

INTRODUCTION

Cerebral edema is a key contributor to death and disability in several forms of brain injury. Current treatment options are limited, reactive, and associated with significant morbidity. Targeted therapies are emerging based on a growing understanding of the molecular underpinnings of cerebral edema.

AREAS COVERED

We review the pathophysiology and relationships between different cerebral edema subtypes to provide a foundation for emerging therapies. Mechanisms for promising molecular targets are discussed, with an emphasis on those advancing in clinical trials, including ion and water channels (AQP4, SUR1-TRPM4) and other proteins/lipids involved in edema signaling pathways (AVP, COX2, VEGF, and S1P). Research on novel treatment modalities for cerebral edema [including recombinant proteins and gene therapies] is presented and finally, insights on reducing secondary injury and improving clinical outcome are offered.

EXPERT OPINION

Targeted molecular strategies to minimize or prevent cerebral edema are promising. Inhibition of SUR1-TRPM4 (glyburide/glibenclamide) and VEGF (bevacizumab) are currently closest to translation based on advances in clinical trials. However, the latter, tested in glioblastoma multiforme, has not demonstrated survival benefit. Research on recombinant proteins and gene therapies for cerebral edema is in its infancy, but early results are encouraging. These newer modalities may facilitate our understanding of the pathobiology underlying cerebral edema.

Hemispheric CSF volume ratio quantifies progression and severity of cerebral edema after acute hemispheric stroke

As swelling occurs, CSF is preferentially displaced from the ischemic hemisphere. The ratio of CSF volume in the stroke-affected hemisphere to that in the contralateral hemisphere may quantify the progression of cerebral edema. We automatically segmented CSF from 1,875 routine CTs performed within 96 hours of stroke onset in 924 participants of a stroke cohort study. In 737 subjects with follow-up imaging beyond 24-hours, edema severity was classified as affecting less than one-third of the hemisphere (CED-1), large hemispheric infarction (LHI, over one-third the hemisphere), without midline shift (CED-2) or with midline shift (CED-3). Malignant edema was LHI resulting in deterioration, requiring osmotic therapy, surgery, or resulting in death. Hemispheric CSF ratio was lower on baseline CT in those with LHI (0.91 vs. 0.97, p < 0.0001) and decreased more rapidly in those with LHI who developed midline shift (0.01 per hour for CED-3 vs. 0.004/hour CED-2). The ratio at 24-hours was lower in those with midline shift (0.41, IQR 0.30-0.57 vs. 0.66, 0.56-0.81 for CED-2). A ratio below 0.50 provided 90% sensitivity, 82% specificity for predicting malignant edema among those with LHI (AUC 0.91, 0.85-0.96). This suggests that the hemispheric CSF ratio may provide an accessible early biomarker of edema severity.

Emerging agents for the treatment and prevention of stroke: progress in clinical trials

INTRODUCTION

Recent years have witnessed unprecedented progress in stroke care, but unmet needs persist regarding the efficacy of acute treatment and secondary prevention. Novel approaches are being tested to enhance the efficacy of thrombolysis or provide neuroprotection in non-thrombolized patients.

AREAS COVERED

The current review highlights pharmaceutical agents under evaluation in clinical trials concerning the acute, subacute, and chronic phase post-stroke. We examine the evidence in favor of tenecteplase as an alternative thrombolytic drug to alteplase, nerinetide as a promising neuroprotective agent, and glibenclamide for reducing edema in malignant hemispheric infarction. We discuss the use of ticagrelor and the promising novel category of factor XI inhibitors in the subacute phase after stroke. We offer our insights on combined rivaroxaban and antiplatelet therapy, PCSK-9 inhibitors, and other non-statin hypolipidemic agents, as well as novel antidiabetic agents that have been shown to reduce cardiovascular events in the long-term.

EXPERT OPINION

Current approaches in stroke treatment and stroke prevention have already transformed stroke care from a linear one-for-all treatment paradigm to a more individualized approach that targets specific patient subgroups with novel pharmaceutical agents. This tendency enriches the therapeutic armamentarium with novel agents developed for specific stroke subgroups.

ABBREVIATIONS

IVT: intravenous thrombolysis; RCTs: randomized-controlled clinical trials; TNK: Tenecteplase; COVID-19: Coronavirus 2019 Disease; EXTEND-IA TNK: The Tenecteplase versus Alteplase Before Endovascular Therapy for Ischemic Stroke trial; AIS: acute ischemic stroke; NNT: number needed to treat; MT: mechanical thrombectomy; sICH: symptomatic intracranial hemorrhage; mRS: modified Rankin Scale; AHA/ASA: American Heart Association/American Stroke Association; ESO: European Stroke Organization; NA-1: Nerinetide; ENACT: Evaluating Neuroprotection in Aneurysm Coiling Therapy; CTA: CT angiography; TIA: transient ischemic attack; CHANCE: Clopidogrel in High-risk patients with Acute Non-disabling Cerebrovascular Events; LOF: loss-of-function; PRINCE: Platelet Reactivity in Acute Nondisabling Cerebrovascular Events; THALES: Acute Stroke or Transient Ischemic Attack Treated with Ticagrelor and ASA [acetylsalicylic acid] for Prevention of Stroke and Death; CHANCE-2: Clopidogrel With Aspirin in High-risk Patients With Acute Non-disabling Cerebrovascular Events II; FXI: Factor XI; PACIFIC-STROKE: Program of Anticoagulation via Inhibition of FXIa by the Oral Compound BAY 2433334-NonCardioembolic Stroke study; COMPASS: Cardiovascular Outcomes for People Using Anticoagulation Strategies; CANTOS-ICAD: Combination Antithrombotic Treatment for Prevention of Recurrent Ischemic Stroke in Intracranial Atherosclerotic Disease; SAMMPRIS: Stenting and Aggressive Medical Therapy for Preventing Recurrent Stroke in Intracranial Stenosis; WASID: Warfarin-Aspirin Symptomatic Intracranial Disease; SPARCL: Stroke Prevention by Aggressive Reduction in Cholesterol Levels; LDL-C: low-density lipoprotein cholesterol; TST: Treat Stroke to Target; IMPROVE-IT: Improved Reduction of Outcomes: Vytorin Efficacy International Trial; PCSK9: proprotein convertase subtilisin-kexin type 9; FOURIER: Further Cardiovascular Outcomes Research with PCSK9 Inhibition in Subjects with Elevated Risk; CLEAR: Cholesterol Lowering via Bempedoic acid, an ACL-inhibiting Regimen; REDUCE-IT: Reduction of Cardiovascular Events With EPA Intervention Trial; STRENGTH: Outcomes Study to Assess STatin Residual Risk Reduction With EpaNova in HiGh CV Risk PatienTs With Hypertriglyceridemia; ACCORD: Action to Control Cardiovascular Risk in Diabetes; ADVANCE: Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation; VADT: Veterans Affairs Diabetes Trial; GLP-1R: Glucagon-like peptide-1 receptor; SGLT2: sodium-glucose cotransporter 2; CONVINCE: COlchicine for preventioN of Vascular Inflammation in Non-CardioEmbolic stroke; PROBE: Prospective Randomized Open-label Blinded Endpoint assessment.

Advances in TRP channel drug discovery: from target validation to clinical studies

Transient receptor potential (TRP) channels are multifunctional signalling molecules with many roles in sensory perception and cellular physiology. Therefore, it is not surprising that TRP channels have been implicated in numerous diseases, including hereditary disorders caused by defects in genes encoding TRP channels (TRP channelopathies). Most TRP channels are located at the cell surface, which makes them generally accessible drug targets. Early drug discovery efforts to target TRP channels focused on pain, but as our knowledge of TRP channels and their role in health and disease has grown, these efforts have expanded into new clinical indications, ranging from respiratory disorders through neurological and psychiatric diseases to diabetes and cancer. In this Review, we discuss recent findings in TRP channel structural biology that can affect both drug development and clinical indications. We also discuss the clinical promise of novel TRP channel modulators, aimed at both established and emerging targets. Last, we address the challenges that these compounds may face in clinical practice, including the need for carefully targeted approaches to minimize potential side-effects due to the multifunctional roles of TRP channels.

Glibenclamide Attenuates Neuroinflammation and Promotes Neurological Recovery After Intracerebral Hemorrhage in Aged Rats

Intracerebral hemorrhage (ICH) is a common disease in the elderly population. Inflammation following ICH plays a detrimental role in secondary brain injury, which is associated with a poor prognosis of patients with ICH, and no efficient pharmacological preventions are available. Here, we investigated the effects of glibenclamide (GLC) on neuroinflammation in an autoblood-induced aged rat (18 months old) model of ICH. Rats were randomized into the sham, vehicle, and GLC groups. First, we investigated the expression level of sulfonylurea receptor 1 (Sur1) surrounding the hematoma after ICH. Then, neurological scores were calculated, and water maze tests, brain water content analysis, western blotting, and immunofluorescence assays were implemented to detect the neuroprotective effect of GLC. The expression of the Sur1-Trpm4 channel was significantly increased in the perihematomal tissue following ICH in aged rats. The GLC administration effectively reduced brain edema and improved neurofunction deficits following ICH. In addition, GLC increased the expression of brain-derived neurotrophic factors and decreased the expression of proinflammatory factors [tumor necrosis factor (TNF)-α,interleukin (IL)-1, and IL-6]. Moreover, GLC markedly reduced Ikappa-B (IκB) kinase (IKK) expression in microglia and nuclear factor (NF)-κB-P65 levels in perihematomal tissue. GLC ameliorated ICH-induced neuroinflammation and improved neurological outcomes in aged rats. In part, GLC may exert these effects by regulating the NF-κB signaling pathway through the Sur1-Trpm4 channel.

Glymphatic System in the Central Nervous System, a Novel Therapeutic Direction Against Brain Edema After Stroke

Stroke is the destruction of brain function and structure, and is caused by either cerebrovascular obstruction or rupture. It is a disease associated with high mortality and disability worldwide. Brain edema after stroke is an important factor affecting neurologic function recovery. The glymphatic system is a recently discovered cerebrospinal fluid (CSF) transport system. Through the perivascular space and aquaporin 4 (AQP4) on astrocytes, it promotes the exchange of CSF and interstitial fluid (ISF), clears brain metabolic waste, and maintains the stability of the internal environment within the brain. Excessive accumulation of fluid in the brain tissue causes cerebral edema, but the glymphatic system plays an important role in the process of both intake and removal of fluid within the brain. The changes in the glymphatic system after stroke may be an important contributor to brain edema. Understanding and targeting the molecular mechanisms and the role of the glymphatic system in the formation and regression of brain edema after stroke could promote the exclusion of fluids in the brain tissue and promote the recovery of neurological function in stroke patients. In this review, we will discuss the physiology of the glymphatic system, as well as the related mechanisms and therapeutic targets involved in the formation of brain edema after stroke, which could provide a new direction for research against brain edema after stroke.

Cerebral Edema in Patients With Large Hemispheric Infarct Undergoing Reperfusion Treatment: A HERMES Meta-Analysis

BACKGROUND AND PURPOSE

Whether reperfusion into infarcted tissue exacerbates cerebral edema has treatment implications in patients presenting with extensive irreversible injury. We investigated the effects of endovascular thrombectomy and reperfusion on cerebral edema in patients presenting with radiological evidence of large hemispheric infarction at baseline.

METHODS

In a systematic review and individual patient-level meta-analysis of 7 randomized controlled trials comparing thrombectomy versus medical therapy in anterior circulation ischemic stroke published between January 1, 2010, and May 31, 2017 (Highly Effective Reperfusion Using Multiple Endovascular Devices collaboration), we analyzed the association between thrombectomy and reperfusion with maximal midline shift (MLS) on follow-up imaging as a measure of the space-occupying effect of cerebral edema in patients with large hemispheric infarction on pretreatment imaging, defined as diffusion-magnetic resonance imaging or computed tomography (CT)-perfusion ischemic core 80 to 300 mL or noncontrast CT-Alberta Stroke Program Early CT Score ≤5. Risk of bias was assessed using the Cochrane tool.

RESULTS

Among 1764 patients, 177 presented with large hemispheric infarction. Thrombectomy and reperfusion were associated with functional improvement (thrombectomy common odds ratio =2.30 [95% CI, 1.32-4.00]; reperfusion common odds ratio =4.73 [95% CI, 1.66-13.52]) but not MLS (thrombectomy β=-0.27 [95% CI, -1.52 to 0.98]; reperfusion β=-0.78 [95% CI, -3.07 to 1.50]) when adjusting for age, National Institutes of Health Stroke Score, glucose, and time-to-follow-up imaging. In an exploratory analysis of patients presenting with core volume >130 mL or CT-Alberta Stroke Program Early CT Score ≤3 (n=76), thrombectomy was associated with greater MLS after adjusting for age and National Institutes of Health Stroke Score (β=2.76 [95% CI, 0.33-5.20]) but not functional improvement (odds ratio, 1.71 [95% CI, 0.24-12.08]).

CONCLUSIONS

In patients presenting with large hemispheric infarction, thrombectomy and reperfusion were not associated with MLS, except in the subgroup with very large core volume (>130 mL) in whom thrombectomy was associated with increased MLS due to space-occupying ischemic edema. Mitigating cerebral edema-mediated secondary injury in patients with very large infarcts may further improve outcomes after reperfusion therapies.

Aflibercept, a VEGF (Vascular Endothelial Growth Factor)-Trap, Reduces Vascular Permeability and Stroke-Induced Brain Swelling in Obese Mice

Background and Purpose

Brain edema is an important underlying pathology in acute stroke, especially when comorbidities are present. VEGF (Vascular endothelial growth factor) signaling is implicated in edema. This study investigated whether obesity impacts VEGF signaling and brain edema, as well as whether VEGF inhibition alters stroke outcome in obese subjects.

Methods

High-fat diet-induced obese mice were subjected to a transient middle cerebral artery occlusion. VEGF-A and VEGFR2 (receptor) expression, infarct volume, and swelling were measured 3 days post-middle cerebral artery occlusion. To validate the effect of an anti-VEGF strategy, we used aflibercept, a fusion protein that has a VEGF-binding domain and acts as a decoy receptor, in human umbilical vein endothelial cells stimulated with rVEGF (recombinant VEGF; 50 ng/mL) for permeability and tube formation. In vivo, aflibercept (10 mg/kg) or IgG control was administered in obese mice 3 hours after transient 30 minutes middle cerebral artery occlusion. Blood-brain barrier integrity was assessed by IgG staining and dextran extravasation in the postischemic brain. A separate cohort of nonobese (lean) mice was subjected to 40 minutes middle cerebral artery occlusion to test the effect of aflibercept on malignant infarction.

Results

Compared with lean mice, obese mice had increased mortality, infarct volume, swelling, and blood-brain barrier disruption. These outcomes were also associated with increased VEGF-A and VEGFR2 expression. Aflibercept reduced VEGF-A-stimulated permeability and tube formation in human umbilical vein endothelial cells. Compared with the IgG-treated controls, mice treated with aflibercept had reduced mortality rates (40% versus 17%), hemorrhagic transformation (43% versus 27%), and brain swelling (28% versus 18%), although the infarct size was similar. In nonobese mice with large stroke, aflibercept neither improved nor exacerbated stroke outcomes.

Conclusions

The study demonstrates that aflibercept selectively attenuates stroke-induced brain edema and vascular permeability in obese mice. These findings suggest the repurposing of aflibercept to reduce obesity-enhanced brain edema in acute stroke.

The Role of Edema in Subacute Lesion Progression After Treatment of Acute Ischemic Stroke

Background: Ischemic lesions commonly continue to progress even days after treatment, and this lesion growth is associated with unfavorable functional outcome in acute ischemic stroke patients. The aim of this study is to elucidate the role of edema in subacute lesion progression and its influence on unfavorable functional outcome by quantifying net water uptake. Methods: We included all 187 patients from the MR CLEAN trial who had high quality follow-up non-contrast CT at 24 h and 1 week. Using a CT densitometry-based method to calculate the net water uptake, we differentiated total ischemic lesion volume (TILV) into edema volume (EV) and edema-corrected infarct volume (ecIV). We calculated these volumes at 24 h and 1 week after stroke and determined their progression in the subacute period. We assessed the effect of 24-h lesion characteristics on EV and ecIV progression. We evaluated the influence of edema and edema-corrected infarct progression on favorable functional outcome after 90 days (modified Rankin Scale: 0-2) after correcting for potential confounders. Lastly, we compared these volumes between subgroups of patients with and without successful recanalization using the Mann-Whitney U-test. Results: Median TILV increased from 37 (IQR: 18-81) ml to 68 (IQR: 30-130) ml between 24 h and 1 week after stroke, while the net water uptake increased from 22 (IQR: 16-26)% to 27 (IQR: 22-32)%. The TILV progression of 20 (8.8-40) ml was mostly caused by ecIV with a median increase of 12 (2.4-21) ml vs. 6.5 (2.7-15) ml of EV progression. Larger TILV, EV, and ecIV volumes at 24 h were all associated with more edema and lesion progression. Edema progression was associated with unfavorable functional outcome [aOR: 0.53 (0.28-0.94) per 10 ml; p-value: 0.05], while edema-corrected infarct progression showed a similar, non-significant association [aOR: 0.80 (0.62-0.99); p-value: 0.06]. Lastly, edema progression was larger in patients without successful recanalization, whereas ecIV progression was comparable between the subgroups. Conclusion: EV increases in evolving ischemic lesions in the period between 1 day and 1 week after acute ischemic stroke. This progression is larger in patients without successful recanalization and is associated with unfavorable functional outcome. However, the extent of edema cannot explain the total expansion of ischemic lesions since edema-corrected infarct progression is larger than the edema progression.

Reversible Ischemic Lesion Hypodensity in Acute Stroke CT Following Endovascular Reperfusion

BACKGROUND AND OBJECTIVES

In acute stroke, early ischemic lesion hypodensity in computed tomography (CT) is considered the imaging hallmark of brain infarction, representing a state of irreversible tissue damage with a continual increase of net water uptake. This dogma is however challenged by rare cases of apparently reversed early lesion hypodensity following complete reperfusion. The purpose of this study was to investigate the occurrence of reversible ischemic edema after endovascular treatment.

METHODS

184 acute ischemic anterior circulation stroke patients were included after consecutive screening. Ischemic brain edema was determined using quantitative lesion net water uptake (NWU) in admission-CT and follow-up CT based on CT-densitometry and ΔNWU was calculated as the difference. The association of edema progression to imaging and clinical parameters was investigated. Clinical outcome was assessed using modified Ranking Scale (mRS) scores at day 90.

RESULTS

27/184 patients (14.7%) showed edema arrest and 3 patients (1.6%) exhibited significant edema reversibility. Higher degree of recanalization (odds ratio (OR): 2.96, 95%CI: 1.46-6.01, p<0.01) and shorter time from imaging to recanalization (OR/hour: 0.32, 95%CI: 0.18-0.54, p<0.0001) were significantly associated with edema arrest or reversibility. Clinical outcome was significantly better in patients without edema progression (median mRS 2 versus mRS 5, p=0.004).

DISCUSSION

Albeit rare, lesion hypodensity considered to be representative of early infarct in acute stroke CT may be reversible following complete recanalization. Arrest of edema progression of acute brain infarct lesions may occur after successful rapid vessel recanalization, resulting in improved functional outcome. Future research is needed to investigate conditions where early revascularization may halt or even reverse vasogenic edema of ischemic tissue.

Cerebrovascular effects of glibenclamide investigated using high-resolution magnetic resonance imaging in healthy volunteers

Glibenclamide inhibits sulfonylurea receptor (SUR), which regulates several ion channels including SUR1-transient receptor potential melastatin 4 (SUR1-TRPM4) channel and ATP-sensitive potassium (K_ATP) channel. Stroke upregulates SURl-TRPM4 channel, which causes a rapid edema formation and brain swelling. Glibenclamide may antagonize the formation of cerebral edema during stroke. Preclinical studies showed that glibenclamide inhibits K_ATP channel-induced vasodilation without altering the basal vascular tone. The in vivo human cerebrovascular effects of glibenclamide have not previously been investigated.In a randomized, double-blind, placebo-controlled, three-way cross-over study, we used advanced 3 T MRI methods to investigate the effects of glibenclamide and K_ATP channel opener levcromakalim on mean global cerebral blood flow (CBF) and intra- and extracranial artery circumferences in 15 healthy volunteers. Glibenclamide administration did not alter the mean global CBF and the basal vascular tone. Following levcromakalim infusion, we observed a 14% increase of the mean global CBF and an 8% increase of middle cerebral artery (MCA) circumference, and glibenclamide did not attenuate levcromakalim-induced vascular changes. Collectively, the findings demonstrate the vital role of K_ATP channels in cerebrovascular hemodynamic and indicate that glibenclamide does not inhibit the protective effects of K_ATP channel activation during hypoxia and ischemia-induced brain injury.

Absent Cortical Venous Filling Is Associated with Aggravated Brain Edema in Acute Ischemic Stroke

BACKGROUND AND PURPOSE

Predicting malignant cerebral edema can help identify patients who may benefit from appropriate evidence-based interventions. We investigated whether absent cortical venous filling is associated with more pronounced early brain edema, which leads to malignant cerebral edema.

MATERIALS AND METHODS

Patients with acute ischemic stroke caused by large-vessel occlusion in the MCA territory who presented between July 2017 and September 2019 to our hospital were included. Collateral filling was rated using the modified Tan scale on CTA, and good collaterals were defined as a score of 2-3. The Cortical Vein Opacification Score (COVES) was calculated, and absent cortical venous filling was defined as a score of 0. Early brain edema was determined using net water uptake on baseline CT images. Malignant cerebral edema was defined as a midline shift of ≥5 mm on follow-up imaging or a massive cerebral swelling leading to decompressive hemicraniectomy or death. Multivariate linear and logistic regression models were performed to analyze data.

RESULTS

A total of 163 patients were included. Net water uptake was significantly higher in patients with absent than in those with favorable cortical venous filling (8.1% versus 4.2%; P < .001). In the multivariable regression analysis, absent cortical venous filling (β = 2.04; 95% CI, 0.75-3.32; P = .002) was significantly and independently associated with higher net water uptake. Absent cortical venous filling (OR, 14.68; 95% CI, 4.03-53.45; P < .001) and higher net water uptake (OR, 1.29; 95% CI, 1.05-1.58; P = .016) were significantly associated with increased likelihood of malignant cerebral edema.

CONCLUSIONS

Patients with absent cortical venous filling were associated with an increased early brain edema and a higher risk of malignant cerebral edema. These patients may be targeted for optimized adjuvant antiedematous treatment.

Effectiveness and safety of glibenclamide for stroke: protocol for a systematic review and meta-analysis

INTRODUCTION

Despite the continuous improvement in modern medical treatment, stroke is still a leading cause of death and disability worldwide. How to effectively improve the survival rate and reduce disability in patients who had a stroke has become the focus of many investigations. Recent findings concerning the benefits of glibenclamide as a neuroprotective drug have initiated a new area for prospective studies on the effects of sulfonylureas. Given the high mortality and disability associated with stroke, it is essential to weigh the benefits of neuroprotective drugs against their safety. Therefore, the objective of the current study is to conduct a systematic review using meta-analysis to assess the benefits and safety of glibenclamide as a neuroprotective drug.

METHODS AND ANALYSIS

This study will analyse randomised clinical trials (RCTs) and observational studies published up to 31 December 2020 and include direct or indirect evidence. Studies will be retrieved by searching PubMed, EMBASE, Web of Science, the Cochrane Library and China National Knowledge Infrastructure (CNKI) and WanFang Databases. The outcomes of this study will be mortality, scores from the Modified Rankin Scale and the occurrence of hypoglycaemic events. The risk of bias will be assessed using the Cochrane risk of bias assessment instrument for RCTs. A random-effect/fixed-effect model will be used to summarise the estimates of the mean difference/risk ratio using a 95% CI.

ETHICS AND DISSEMINATION

This meta-analysis is a secondary research project, which is based on previously published data. Therefore, ethical approval and informed consent were not required for this meta-analysis. The results of this study will be submitted to a peer-reviewed journal for publication.

PROSPERO REGISTRATION NUMBER

CRD42020144674.

Early Prediction of Malignant Cerebellar Edema in Posterior Circulation Stroke Using Quantitative Lesion Water Uptake

BACKGROUND

Malignant cerebellar edema (MCE) is a life-threatening complication of ischemic posterior circulation stroke that requires timely diagnosis and management. Yet, there is no established imaging biomarker that may serve as predictor of MCE. Early edematous water uptake can be determined using quantitative lesion water uptake, but this biomarker has only been applied in anterior circulation strokes.

OBJECTIVE

To test the hypothesis that lesion water uptake in early posterior circulation stroke predicts MCE.

METHODS

A total 179 patients with posterior circulation stroke and multimodal admission CT were included. A total of 35 (19.5%) patients developed MCE defined by using an established 10-point scale in follow-up CT, of which ≥4 points are considered malignant. Posterior circulation net water uptake (pcNWU) was quantified in admission CT based on CT densitometry and compared with posterior circulation Acute Stroke Prognosis Early CT Score (pc-ASPECTS) as predictor of MCE using receiver operating curve (ROC) analysis and logistic regression analysis.

RESULTS

Acute pcNWU within the early ischemic lesion was 24.6% (±8.4) for malignant and 7.2% (±7.4) for nonmalignant infarctions, respectively (P < .0001). Based on ROC analysis, pcNWU above 14.9% identified MCE with high discriminative power (area under the curve: 0.94; 95% CI: 0.89-0.97). Early pcNWU (odds ratio [OR]: 1.28; 95% CI: 1.15-1.42, P < .0001) and pc-ASPECTS (OR: 0.71, 95% CI: 0.53-0.95, P = .02) were associated with MCE, adjusted for age and recanalization status.

CONCLUSION

Quantitative pcNWU in early posterior circulation stroke is an important marker for MCE. Besides pc-ASPECTS, lesion water uptake measurements may further support identifying patients at risk for MCE at an early stage indicating stricter monitoring and consideration for further therapeutic measures.

Net Water Uptake Calculated in Standardized and Blindly Outlined Regions of the Middle Cerebral Artery Territory Predicts the Development of Malignant Edema in Patients With Acute Large Hemispheric Infarction

Background and purpose: Previous studies have demonstrated that Net Water Uptake (NWU) is associated with the development of malignant edema (ME). The current study aimed to investigate whether NWU calculated in standardized and blindly outlined regions of the middle cerebral artery can predict the development of ME. Methods: We retrospectively included 119 patients suffering from large hemispheric infarction within onset of 24 h. The region of the middle cerebral artery territory was blindly outlined in a standard manner to calculate NWU. Patients were divided into two groups according to the occurrence of ME, which is defined as space-occupying infarct requiring decompressive craniotomy or death due to cerebral hernia in 7 days from onset. The clinical characteristics were analyzed, and the receiver operating characteristic curve (ROC curve) was used to assess the predictive ability of NWU and other factors for ME. Results: Multivariable analysis showed that NWU was an independent predictor of ME (OR 1.168, 95% CI 1.041-1.310). According to the ROC curve, NWU≥8.127% identified ME with good predictive power (AUC 0.734, sensitivity 0.656, specificity 0.862). Conclusions: NWU calculated in standardized and blindly outlined regions of the middle cerebral artery territory is also a good predictor for the development of ME in patients with large hemispheric infarction.

BIIB093 (intravenous glibenclamide) for the prevention of severe cerebral edema

Background:

Vasogenic edema in the setting of acute ischemic stroke can be attributed to the opening of transient receptor potential 4 channels, which are expressed in the setting of injury and regulated by sulfonylurea receptor 1 (SUR1) proteins. Glibenclamide, also known as glyburide, RP-1127, Cirara, and BIIB093, is a second-generation sulfonylurea that binds SUR1 at potassium channels and may significantly reduce cerebral edema following stroke, as evidenced by recent clinical trials. This review provides a comprehensive analysis of clinical considerations of glibenclamide use and current patient outcomes when administered in the setting of acute ischemic stroke to reduce severe edema.

Methods:

National databases (MEDLINE, EMBASE, Cochrane, and Google scholar databases) were searched to identify studies that reported on the clinical outcomes of glibenclamide administered immediately following acute ischemic stroke.

Results:

The pharmacological mechanism of glibenclamide was reviewed in depth as well as the known indications and contraindications to receiving treatment. Eight studies were identified as having meaningful clinical outcome data, finding statistically significant differences in glibenclamide treatment groups ranging from matrix metalloproteinase-9 serum levels, midline shift, modified Rankin Scores, National Institute of Health Stroke Score, and mortality endpoints.

Conclusion:

Studies analyzing the GAMES-Pilot and GAMES-PR trials suggest that glibenclamide has a moderate, however, measurable effect on intermediate biomarkers and clinical endpoints. Meaningful conclusions are limited by the small sample size of patients studied.

Potential Therapies for Cerebral Edema After Ischemic Stroke: A Mini Review

Stroke is the leading cause of global mortality and disability. Cerebral edema and intracranial hypertension are common complications of cerebral infarction and the major causes of mortality. The formation of cerebral edema includes three stages (cytotoxic edema, ionic edema, and vasogenic edema), which involve multiple proteins and ion channels. A range of therapeutic agents that successfully target cerebral edema have been developed in animal studies, some of which have been assessed in clinical trials. Herein, we review the mechanisms of cerebral edema and the research progress of anti-edema therapies for use after ischemic stroke.

Neutrophil-to-Lymphocyte Ratio Predicts Cerebral Edema and Clinical Worsening Early After Reperfusion Therapy in Stroke

BACKGROUND AND PURPOSE

The mechanisms linking systemic inflammation to poor outcome in ischemic stroke are not fully understood. The authors investigated if peripheral inflammation following reperfusion therapy leads to an increase in cerebral edema (CED), thus hindering the clinical recovery.

METHODS

We designed a single-center study conducted at Centro Hospitalar Universitário São João between 2017 and 2019. Inclusion criteria were being adult, having an anterior circulation acute ischemic stroke, and receiving reperfusion therapy. Neutrophil-to-lymphocyte, platelet-to-lymphocyte ratios, and the systemic inflammatory response syndrome criteria were determined. The presence and grade of CED were evaluated on the computed tomography performed 24 hours following event. The clinical outcomes included early neurological deterioration and functional dependence at 90 days. Adjusted odds ratio and 95% CI were obtained by ordinal and logistic regression models. Optimal cutoff values were defined using receiver operating characteristic analysis in the training cohort and validated in an independent data set.

RESULTS

Five hundred fifty-three patients were included. Neutrophil-to-lymphocyte increased with higher degrees of CED at 24 hours (adjusted odds ratio, 1.34 [1.09-1.68], P<0.01) and was associated with early neurological deterioration (adjusted odds ratio, 1.30 [1.04-1.63], P<0.05) and poor functional status at 90 days (adjusted odds ratio, 1.79 [1.28-2.48], P<0.01). Platelet-to-lymphocyte was not associated with the outcomes. Systemic inflammatory response syndrome was related to CED due to altered white blood cell counts. Neutrophil-to-lymphocyte was the best predictor with an area under the curve around 0.7. Neutrophil-to-lymphocyte ≥7 had and accuracy, sensitivity, and specificity around 60%.

CONCLUSIONS

Increased systemic inflammation is linked to the severity of CED early after reperfusion therapy in stroke. Easily obtained inflammatory markers convey early warning alerts for patients at risk of severe neurological complications with an impact on long-term functional outcome. CED quantification should be included as an end point in proof-of-concept trials in immunomodulation in stroke.

Ischemic lesion water homeostasis after thrombectomy for large vessel occlusion stroke within the anterior circulation: The impact of age

The effect of age on lesion pathophysiology in the context of thrombectomy has been poorly investigated. We aimed to investigate the impact of age on ischemic lesion water homeostasis measured with net water uptake (NWU) within a multicenter cohort of patients receiving thrombectomy for anterior circulation large vessel occlusion (LVO) stroke. Lesion-NWU was quantified in multimodal CT on admission and 24 h for calculating Δ-NWU as their difference. The impact of age and procedural parameters on Δ-NWU was analyzed. Multivariable regression analysis was performed to identify significant predictors for Δ-NWU. Two hundred and four patients with anterior circulation stroke were included in the retrospective analysis. Comparison of younger and elderly patients showed no significant differences in NWU on admission but significantly higher Δ-NWU (p = 0.005) on follow-up CT in younger patients. In multivariable regression analysis, higher age was independently associated with lowered Δ-NWU (95% confidence interval: -0.59 to -0.16, p < 0.001). Although successful recanalization (TICI ≥ 2b) significantly reduced Δ-NWU progression by 6.4% (p < 0.001), younger age was still independently associated with higher Δ-NWU (p < 0.001). Younger age is significantly associated with increased brain edema formation after thrombectomy for LVO stroke. Younger patients might be particularly receptive targets for future adjuvant neuroprotective drugs that influence ischemic edema formation.

The Role of Transient Receptor Potential Channels in Blood-Brain Barrier Dysfunction after Ischemic Stroke

Stroke is the leading cause of long-term disability, demanding an ever-increasing need to find treatment. Transient receptor potential (TRP) channels are nonselective Ca²⁺-permeable channels, among which TRPC, TRPM, and TRPV are widely expressed in the brain. Dysfunction of the blood brain barrier (BBB) is a core feature of stroke and is associated with severity of injury. As studies have shown, TRP channels influence various neuronal functions by regulating the BBB. Here, we briefly review the role of TRP channel in the BBB dysfunction after stroke, and explore the therapeutic potential of TRP-targeted therapy.

Quantitative Serial CT Imaging-Derived Features Improve Prediction of Malignant Cerebral Edema after Ischemic Stroke

INTRODUCTION

Malignant cerebral edema develops in a small subset of patients with hemispheric strokes, precipitating deterioration and death if decompressive hemicraniectomy (DHC) is not performed in a timely manner. Predicting which stroke patients will develop malignant edema is imprecise based on clinical data alone. Head computed tomography (CT) imaging is often performed at baseline and 24-h. We determined the incremental value of incorporating imaging-derived features from serial CTs to enhance prediction of malignant edema.

METHODS

We identified hemispheric stroke patients at three sites with NIHSS ≥ 7 who had baseline as well as 24-h clinical and CT imaging data. We extracted quantitative imaging features from baseline and follow-up CTs, including CSF volume, intracranial reserve (CSF/cranial volume), as well as midline shift (MLS) and infarct-related hypodensity volume. Potentially lethal malignant edema was defined as requiring DHC or dying with MLS over 5-mm. We built machine-learning models using logistic regression first with baseline data and then adding 24-h data including reduction in CSF volume (ΔCSF). Model performance was evaluated with cross-validation using metrics of recall (sensitivity), precision (predictive value), as well as area under receiver-operating-characteristic and precision-recall curves (AUROC, AUPRC).

RESULTS

Twenty of 361 patients (6%) died or underwent DHC. Baseline clinical variables alone had recall of 60% with low precision (7%), AUROC 0.59, AUPRC 0.15. Adding baseline intracranial reserve improved recall to 80% and AUROC to 0.82 but precision remained only 16% (AUPRC 0.28). Incorporating ΔCSF improved AUPRC to 0.53 (AUROC 0.91) while all imaging features further improved prediction (recall 90%, precision 38%, AUROC 0.96, AUPRC 0.66).

CONCLUSION

Incorporating quantitative CT-based imaging features from baseline and 24-h CT enhances identification of patients with malignant edema needing DHC. Further refinements and external validation of such imaging-based machine-learning models are required.

Ischemic lesion growth in acute stroke: Water uptake quantification distinguishes between edema and tissue infarct

Infarct growth from the early ischemic core to the total infarct lesion volume (LV) is often used as an outcome variable of treatment effects, but can be overestimated due to vasogenic edema. The purpose of this study was (1) to assess two components of early lesion growth by distinguishing between water uptake and true net infarct growth and (2) to investigate potential treatment effects on edema-corrected net lesion growth. Sixty-two M1-MCA-stroke patients with acute multimodal and follow-up CT (FCT) were included. Ischemic lesion growth was calculated by subtracting the initial CTP-derived ischemic core volume from the LV in the FCT. To determine edema-corrected net lesion growth, net water uptake of the ischemic lesion on FCT was quantified and subtracted from the volume of uncorrected lesion growth. The mean lesion growth without edema correction was 20.4 mL (95% CI: 8.2-32.5 mL). The mean net lesion growth after edema correction was 7.3 mL (95% CI: -2.1-16.7 mL; p < 0.0001). Lesion growth was significantly overestimated due to ischemic edema when determined in early-FCT imaging. In 18 patients, LV was lower than the initial ischemic core volume by CTP. These apparently "reversible" core lesions were more likely in patients with shorter times from symptom onset to imaging and higher recanalization rates.

SUR1-TRPM4 channels, not KATP, mediate brain swelling following cerebral ischemia

BACKGROUND

Preclinical and emerging clinical data show that glibenclamide reduces space occupying edema and brain swelling following cerebral ischemia. Glibenclamide is a potent inhibitor of numerous sulfonylurea receptor (SUR)-regulated channels, including K_ATP (SUR1-KIR6.2, SUR2A-KIR6.2, SUR2B-KIR6.2, SUR2B-KIR6.1) and SUR1-TRPM4. Here, we used molecularly specific oligodeoxynucleotides (ODNs) to investigate the role of various SUR-regulated ion channel subunits in post-ischemic brain swelling.

METHODS

Focal cerebral ischemia was induced in adult male rats by permanent middle cerebral artery occlusion (pMCAo). We used this model to study the effects of antisense-ODNs (AS-ODNs) directed against Abcc8/SUR1, Trpm4/TRPM4, Kcnj8/KIR6.1 and Kcnj11/KIR6.2 on hemispheric swelling, with sense or scrambled ODNs used as controls. We used antibody-based Förster resonance energy transfer (immuno-FRET) and co-immunoprecipitation to study the co-assembly of SUR1-TRPM4 heteromers.

RESULTS

In the combined control groups administered sense or scrambled ODNs, pMCAo resulted in uniformly large infarct volumes (mean ± SD: 57.4 ± 8.8 %; n = 34) at 24 h after onset of ischemia, with no effect of AS-ODNs on infarct size. In controls, hemispheric swelling was 23.9 ± 4.1 % (n = 34), and swelling was linearly related to infarct volume (P < 0.02). In the groups administered anti-Abcc8/SUR1 or anti-Trpm4/TRPM4 AS-ODN, hemispheric swelling was significantly less, 11.6 ± 3.9 % and 12.8 ± 5.8 % respectively (P < 0.0001), and the relationship between infarct volume and swelling was reduced and not significant. AS-ODNs directed against Kcnj8/KIR6.1 and Kcnj11/KIR6.2 had no significant effect on hemispheric swelling (23.3 ± 5.4 % and 22.9 ± 5.8 % respectively). Post-ischemic tissues showed co-assembly of SUR1-TRPM4 heteromers.

CONCLUSIONS

Post-ischemic hemispheric swelling can be decoupled from infarct volume. SUR1-TRPM4 channels, not K_ATP, mediate post-ischemic brain swelling.

Reduction in Cerebrospinal Fluid Volume as an Early Quantitative Biomarker of Cerebral Edema After Ischemic Stroke

Background and Purpose- Cerebral edema (CED) develops in the hours to days after stroke; the resulting increase in brain volume may lead to midline shift (MLS) and neurological deterioration. The time course and implications of edema formation are not well characterized across the spectrum of stroke. We analyzed displacement of cerebrospinal fluid (ΔCSF) as a dynamic quantitative imaging biomarker of edema formation. Methods- We selected subjects enrolled in a stroke cohort study who presented within 6 hours of onset and had baseline and ≥1 follow-up brain computed tomography scans available. We applied a neural network-based algorithm to quantify hemispheric CSF volume at each imaging time point and modeled CSF trajectory over time (using a piecewise linear mixed-effects model). We evaluated ΔCSF within the first 24 hours as an early biomarker of CED (defined as developing MLS on computed tomography beyond 24 hours) and poor outcome (modified Rankin Scale score, 3-6). Results- We had serial imaging in 738 subjects with stroke, of whom 91 (13%) developed CED with MLS. Age did not differ (69 versus 70 years), but baseline National Institutes of Health Stroke Scale was higher (16 versus 7) and baseline CSF volume lower (132 versus 161 mL, both P<0.001) in those with CED. ΔCSF was faster in those developing MLS, with the majority seen by 24 hours (36% versus 11% or 2.4 versus 0.8 mL/h; P<0.0001). Risk of CED almost doubled for every 10% ΔCSF within 24 hours (odds ratio, 1.76 [95% CI, 1.46-2.14]), adjusting for age, glucose, and National Institutes of Health Stroke Scale. Risk of neurological deterioration (1.6-point increase in National Institutes of Health Stroke Scale at 24 hours) and poor outcome (adjusted odds ratio, 1.34 [95% CI, 1.15-1.56]) was also greater for every 10% increase in ΔCSF. Conclusions- CSF volumetrics provides quantitative evaluation of early edema formation. ΔCSF from baseline to 24-hour computed tomography is a promising early biomarker for the development of MLS and worse neurological outcome.

Patients with low Alberta Stroke Program Early CT Score (ASPECTS) but good collaterals benefit from endovascular recanalization

Background

Benefit of thrombectomy in patients with a low initial Alberta Stroke Program Early CT Score (ASPECTS) is still uncertain. We hypothesized that, despite low ASPECTS, patients may benefit from endovascular recanalization if good collaterals are present.

Methods

Ischemic stroke patients with large vessel occlusion in the anterior circulation and an ASPECTS of ≤5 were analyzed. Collateral status (CS) was assessed using a 5-point-scoring system in CT angiography with poor CS defined as CS=0–1. Clinical outcome was determined using the modified Rankin Scale (mRS) score after 90 days. Edema formation was measured in admission and follow-up CT by net water uptake.

Results

27/100 (27%) patients exhibited a CS of 2–4. 50 patients underwent successful vessel recanalization and 50 patients had a persistent vessel occlusion. In multivariable logistic regression analysis, collateral status (OR 3.0; p=0.003) and vessel recanalization (OR 12.2; p=0.009) significantly increased the likelihood of a good outcome (mRS 0–3). A 1-point increase in CS was associated with 1.9% (95% CI 0.2% to 3.7%) lowered lesion water uptake in follow-up CT .

Conclusion

Endovascular recanalization in patients with ASPECTS of ≤5 but good collaterals was linked to improved clinical outcome and attenuated edema formation. Collateral status may serve as selection criterion for thrombectomy in low ASPECTS patients.