Early Neurological Change After Ischemic Stroke Is Associated With 90-Day Outcome

Identifying the predictors of ultra early neurological improvement and its role in functional outcome after endovascular thrombectomy in acute ischemic stroke

Background and purpose

Using post-treatment methods to predict functional outcomes of acute ischemic stroke (AIS) patients undergoing endovascular thrombectomy (EVT) is crucial in stroke medicine. The National Institute of Health Stroke Scale (NIHSS) score at 24 h has been widely used; however, there is a paucity of data on using earlier NIHSS scores and their association with outcome. In this study, we aimed to investigate the usage of NIHSS at 1-h time window -ultra-early neurological improvement (UENI)- as a surrogate marker associated with the functional outcomes of AIS patients treated with EVT.

Methods

We included 485 adults (≥18 years old) who underwent emergency EVT at four academic comprehensive stroke centers between 2020 and 2021. Patients with pre-EVT Alberta Stroke Program Early CT Score (ASPECTS) < 6, missing follow-up data, and missing data of the first hour NIHSS were excluded (n = 20). UENI was defined as post-EVT NIHSS reduction of 4 points or more or NIHSS as 0-1 within 1-h post-EVT. An mRS score of 0-2 after three months was defined as favorable outcome, and independent walking independence was defined as mRS of 3.

Results

A total of 465 patients were included in our final analysis. We identified 122 (26.2%) patients with UENI. While 82.79% of the patients with UENI achieved favorable functional outcomes at 3-months, only 32.36% of patients without UENI had favorable functional outcome (p < 0.0001). In addition, lower hospitalization costs were associated with patients who had UENI, compared to No-UENI (p = 0.003). A multivariate logistic regression analysis revealed that younger age (p < 0.0001), shorter last know normal to puncture time (LKNPT) (p = 0.013), higher pre-treatment ASPECTS (p = 0.039), final modified thrombolysis in cerebral infarction (mTICI) ≥2b (p = 0.002), and fewer number of EVT attempts (p = 0.002) were variables independently associated with UENI. The presence of UENI was independently associated with a better outcome OR: 7.999 (95% C.I. 4.415-14.495).

Conclusion

UENI was observed in about a quarter of patients with AIS undergoing EVT. Younger age, shorter LKNPT, higher pre-treatment ASPECTS, final mTICI≥2b, and fewer number of EVT attempts, were independently associated with UENI. The presence of UENI was independently associated with better functional outcome at 3 months.

Analyzing the serum biochemical factors that influence early neurological deterioration in ischemic Stroke patients and developing a nomogram prediction model

Background

To investigate the risk factors associated with early neurological deterioration (END) in ischemic stroke (IS) patients and develop a predictive nomogram model.

Methods

General clinical data from 220 IS patients treated between December 2022 and November 2023 were collected for observation. The study's inclusion and exclusion criteria select patients aged 18+ with a first-time diagnosis of IS who undergo lab tests within 24 hours of admission while excluding those with multiple organ dysfunction, sensory impairments, coagulation disorders, or other serious medical conditions. Based on the National Institutes of Health Stroke Scale (NIHSS) in the United States, patients were categorized into two groups: END (n=69) and non-END (n=151). Both groups' basic demographics, medical history, and biochemical test results were compared. Influencing factors were identified using the least absolute shrinkage and selection operator (LASSO) method, and these variables were included in a multivariate logistic regression analysis to construct a nomogram for predicting END in IS patients. Model performance was evaluated using internal validation with the Bootstrap method, assessing discrimination, calibration, and clinical validity.

Results

Factors such as history of diabetes, fasting plasma glucose (FBG), triglyceride (TG), homocysteine (Hcy), and C-reactive protein (CRP) were identified as single factors for early functional deterioration in IS patients (P<0.05). A logistic regression model was established with END as the dependent variable and significant single factors (P<0.05) as independent variables. The results indicated that diabetes history (OR=1.398, P=0.301), TG (OR= 6.149, P<0.05), ASPECT score (OR=7.641, P<0.05), FBG (OR=2.172, P<0.05), CRP (OR=1.706, P<0.05), NIHSS score 7 days post-admission (OR=1.336, P<0.05), and Hcy (OR=1.425, P<0.05) were independent risk factors for END in IS patients (P<0.05). ROC analysis showed an ASPECT area under the curve of 0.910 (95% CI:0.864 to 0.944), with 84.06% sensitivity and 86.09% specificity. Hcy had an area under the curve of 0.808 (95% CI:0.750 to 0.858), with 79.71% sensitivity and 70.20% specificity. FBG had an area under the curve of 0.847 (95% CI:0.793 to 0.892), with 69.57% sensitivity and 95.36% specificity. TG had an area under the curve of 0.937 (95% CI: 0.896-0.965), with 91.30% sensitivity and 82.78% specificity. NIHSS had an area under the curve of 0.857 (95% CI: 0.803-0.900), with 89.86% sensitivity and 70.20% specificity. A nomogram model for END risk prediction was constructed based on the logistic regression analysis results, assigning preliminary scores for each of the 9 predictive factors. The total score, ranging from 0-100 points, was used to predict END risk in patients (0-100%). The constructed nomogram model showed that ASPECT was 59.2, Hcy was 84.0, FBG was 61.4, TG7.0 mmol/L was 39.4, and NIHSS was 98.1 with a total score of 345.7 which predicted the risk of END at 68.9%.

Conclusions

ASPECT, Hcy, FBG, TG, and NIHSS are independent factors influencing END after IS. On this basis, a visual predictive nomogram model is constructed to predict the risk of END in patients accurately.

Clinical outcomes of patients with unsuccessful mechanical thrombectomy versus best medical management of medium vessel occlusion stroke in the middle cerebral artery territory

BACKGROUND

Current randomized controlled trials are investigating the efficacy and safety of mechanical thrombectomy (MT) in patients with medium vessel occlusion (MeVO) stroke. Whether best medical management (MM) is more efficient than unsuccessful vessel recanalization during MT remains unknown.

METHODS

This was a retrospective cohort study using data from 37 academic centers across North America, Asia, and Europe between September 2017 and July 2021. Only patients with occlusion of the distal branches (M2 and M3) of the middle cerebral artery territory were included. Unsuccessful MT was defined as a modified Thrombolysis in Cerebral Infarction score of 0-2a. Propensity score matching was used to control for confounders. The primary outcome was functional independence, defined as a modified Rankin Scale (mRS) score of 0-2 at 90 days after treatment. Multivariable regression analysis was used to assess factors associated with the primary outcome.

RESULTS

Of 2903 patients screened for eligibility, 532 patients were analyzed (266 per group) after propensity score matching. The MM group had superior functional outcomes, with 32% achieving mRS 0-1 at 90 days compared with 21% in the MT group (P=0.011). Patients in the MM group also had significantly lower rates of symptomatic intracranial hemorrhage (sICH) (3.4% vs 16%, P<0.001) and any hemorrhage (18% vs 48%, P<0.001). On multivariable regression, unsuccessful MT was associated with reduced odds of functional independence (OR 0.50, 95% CI 0.29 to 0.85, P=0.011) and increased odds of sICH (OR 4.32, 95% CI 1.84 to 10.10, P<0.001). Mortality rates were similar between groups (27% in MM vs 29% in MT, P=0.73).

CONCLUSION

Unsuccessful MT for MeVO was linked to worse outcomes than best MM. These findings highlight the risks of prolonged attempts and emphasize the importance of efficient procedural decision-making to reduce complications and improve patient outcomes.

Sex-Stratified Genome-Wide Association Study in the Spanish Population Identifies a Novel Locus for Lacunar Stroke

BACKGROUND

Ischemic stroke (IS) represents a significant health burden globally, necessitating a better understanding of its genetic underpinnings to improve prevention and treatment strategies. Despite advances in IS genetics, studies focusing on the Spanish population and sex-stratified analyses are lacking.

METHODS

A case-control genome-wide association study was conducted with 9081 individuals (3493 IS cases and 5588 healthy controls). IS subtypes using Trial of ORG 10172 in Acute Stroke Treatment criteria were explored in a sex-stratified approach. Replication efforts involved the MEGASTROKE, GIGASTROKE, and the UK Biobank international cohorts. Post-genome-wide association study analysis included: in silico proteomic analysis, gene-based analysis, quantitative trait loci annotation, transcriptome-wide association analysis, and bioinformatic analysis using chromatin accessibility data.

RESULTS

Identified as associated with IS and its subtypes were 4 significant and independent loci. Replication confirmed 5p15.2 as a new locus associated with small-vessel occlusion stroke, with rs59970332-T as the lead variant (beta [SE], 0.13 [0.02]; P=4.34×10-8). Functional analyses revealed CTNND2 given proximity and its implication in pathways involved in vascular integrity and angiogenesis. Integration of Hi-C data identified additional potentially modulated genes, and in silico proteomic analysis suggested a distinctive blood proteome profile associated with the lead variant. Gene-set enrichment analyses highlighted pathways consistent with small-vessel disease pathogenesis. Gene-based associations with known stroke-related genes such as F2 and FGG were also observed, reinforcing the relevance of our findings.

CONCLUSIONS

We found CTNND2 as a potential key molecule in small-vessel occlusion stroke risk, and predominantly in males. This study sheds light on the genetic architecture of IS in the Spanish population, providing novel insights into sex-specific associations and potential molecular mechanisms. Further research, including replication in larger cohorts, is essential for a comprehensive understanding of these findings and for their translation to clinical practice.

Comparison of predictors of failure of early neurological improvement after successful endovascular treatment for posterior and anterior circulation large vessel occlusion: Data from ANGEL-ACT registry

PURPOSE

To identify and compare the predictors of failure of early neurological improvement (fENI)after successful EVT for anterior circulation large vessel occlusion (ACLVO) and posterior circulation LVO (PCLVO).

METHODS

Subjects were selected from the ANGEL-ACT registry. fENI was defined as unchanged or worsened in National Institutes of Health Stroke Scale score (NIHSS) between admission and 24 h after EVT. Predictors of fENI after successful EVT (mTICI 2b-3) were determined via center-adjusted analyses. Univariable and multivariable comparisons between ACLVO and PCLVO were performed.

RESULTS

A total of 1447 patients, 1128 were with ACLVO, and 319 were with PCLVO. Among the patients with ACLVO, there were 409 patients (36.3%) with fENI and 719 patients (63.7%) with ENI. We observed that pre-stroke mRS scale score of 2 (odd ratio[OR] 95% confidence interval[CI], 6.93[1.99-24.10], P = 0.002), initial NIHSS score (OR per point[95%CI], 0.97[0.95-0.99], P = 0.012), diabetes (OR[95%CI], 1.56[1.08-2.25], P = 0.017), previous ICH (OR[95%CI] 9.21[1.76-48.15], P = 0.008), local anesthesia (OR[95%CI] 1.63[1.10-2.42], P = 0.014), onset-to-puncture time (OR[95%CI], 1.001[1.000-1.001], P = 0.009), symptomatic ICH (OR[95%CI] 3.90[2.27-6.69], P < 0.001), and continued use of tirofiban within 2 h after EVT (OR[95%CI], 0.69[0.51-0.93], P = 0.014) were independent predictors of fENI of ACLVO after EVT. Among the patients with PCLVO, there were 112 patients (35.1%) with fENI and 207 patients (64.9%) with ENI. In contrast, admission SBP (OR[95%CI], 0.98[0.97-0.99], P = 0.012), and vascular dissection within 2 h after EVT (OR[95%CI], 7.23[1.33-39.13], P = 0.022) were independent predictors of fENI of PCLVO after EVT.

CONCLUSION

In selected patients, successful EVT can lead to similar outcomes in PCLVO and ACLVO. Some predictors of fENI in both anterior circulation and posterior circulation were identified in our study, which should be highly considered in the clinical practice in LVO patients undergoing EVT.

Evaluating the interaction between hemorrhagic transformation and cerebral edema on functional outcome after ischemic stroke

BACKGROUND

Hemorrhagic transformation (HT) and cerebral edema (CED) are both major complications following ischemic stroke, but few studies have evaluated their overlap. We evaluated the frequency and predictors of CED/HT overlap and whether their co-occurrence impacts functional outcome more than each in isolation.

METHODS

892 stroke patients enrolled in a prospective study had follow-up CT imaging evaluated for HT and CED; the latter was quantified using the ratio of hemispheric CSF volumes (with hemispheric CSF ratio < 0.90 used as the CED threshold). The interaction between HT and CED on functional outcome (using modified Rankin Scale at 3 months) was compared to that for each condition separately.

RESULTS

Among the 275 (31%) who developed HT, 233 (85%) manifested hemispheric CSF ratio < 0.9 (CED/HT), with this overlap group representing half of the 475 with measurable CED. Higher baseline NIHSS scores and larger infarct volumes were observed in the CED/HT group compared with those with CED or HT alone. Functional outcome was worse in those with CED/HT [median mRS 3 (IQR 2-5)] than those with CED [median 2 (IQR 1-4)] or HT alone [median 1 (IQR 0-2), p < 0.0001]. Overlap of CED/HT independently predicted worse outcome [OR 1.89 (95% CI: 1.12-3.18), p = 0.02] while HT did not; however, CED/HT was no longer associated with worse outcome after adjusting for severity of CED [adjusted OR 0.35 (95% CI: 0.23, 0.51) per 0.21 lower hemispheric CSF ratio, p < 0.001].

CONCLUSIONS

Most stroke patients with HT also have measurable CED. The co-occurrence of CED and HT occurs in larger and more severe strokes and is associated with worse functional outcome, although this is driven by greater severity of stroke-related edema in those with HT.

Twenty-Four-Hour Post-Thrombolysis NIHSS Score As the Strongest Prognostic Predictor After Acute Ischemic Stroke: ENCHANTED Study

BACKGROUND

This study was conducted to determine optimal predictive ability of National Institutes of Health Stroke Scale (NIHSS) measurements at baseline, 24 hours, and change from baseline to 24 hours after thrombolysis on functional recovery in patients with acute ischemic stroke who participated in the ENCHANTED (Enhanced Control of Hypertension and Thrombolysis Stroke Study).

METHODS AND RESULTS

ENCHANTED was an international, multicenter, 2×2 quasifactorial, prospective, randomized open trial of low-dose versus standard-dose intravenous alteplase and intensive versus guideline-recommended blood pressure lowering in thrombolysis-eligible patients with acute ischemic stroke. Absolute (baseline minus 24 hours) and percentage (absolute change/baseline × 100) changes in NIHSS scores were calculated. Receiver operating characteristic curve analyses assessed performance of different NIHSS measurements on 90-day favorable functional recovery (modified Rankin Scale [mRS] score 0-2) and excellent functional recovery (mRS score 0-1). Youden index was used to identify optimal predictor cutoff points. A total of 4410 patients in the ENCHANTED trial were enrolled. The 24-hour NIHSS score had the highest discriminative ability for predicting favorable 90-day functional recovery (mRS score 0-2; area under the curve 0.866 versus 0.755, 0.689, 0.764; P<0.001) than baseline, absolute, and percentage change of NIHSS score, respectively. The optimal cutoff point of 24-hour NIHSS score for predicting favorable functional recovery was ≤4 (sensitivity 66.5%, specificity 87.1%, adjusted odds ratio, 9.44 [95% CI, 7.77-11.48]). The 24-hour NIHSS score (≤3) was the best predictor of 90-day excellent functional recovery (mRS score 0-1). Findings were consistent across subgroups, including sex, race, baseline NIHSS score, stroke subtype, and age.

CONCLUSIONS

In thrombolysis-eligible patients with acute ischemic stroke, 24-hour NIHSS score (optimal cutpoint of 4) is the strongest predictor of 90-day functional recovery over baseline and early change of NIHSS score.

REGISTRATION

URL: https://clinicaltrials.gov. Unique Identifier: NCT01422616.

Adaptive Metabolic Responses Facilitate Blood-Brain Barrier Repair in Ischemic Stroke via BHB-Mediated Epigenetic Modification of ZO-1 Expression

Adaptive metabolic responses and innate metabolites hold promising therapeutic potential for stroke, while targeted interventions require a thorough understanding of underlying mechanisms. Adiposity is a noted modifiable metabolic risk factor for stroke, and recent research suggests that it benefits neurological rehabilitation. During the early phase of experimental stroke, the lipidomic results showed that fat depots underwent pronounced lipolysis and released fatty acids (FAs) that feed into consequent hepatic FA oxidation and ketogenesis. Systemic supplementation with the predominant ketone beta-hydroxybutyrate (BHB) is found to exert discernible effects on preserving blood-brain barrier (BBB) integrity and facilitating neuroinflammation resolution. Meanwhile, blocking FAO-ketogenesis processes by administration of CPT1α antagonist or shRNA targeting HMGCS2 exacerbated endothelial damage and aggravated stroke severity, whereas BHB supplementation blunted these injuries. Mechanistically, it is unveiled that BHB infusion is taken up by monocarboxylic acid transporter 1 (MCT1) specifically expressed in cerebral endothelium and upregulated the expression of tight junction protein ZO-1 by enhancing local β-hydroxybutyrylation of H3K9 at the promoter of TJP1 gene. Conclusively, an adaptive metabolic mechanism is elucidated by which acute lipolysis stimulates FAO-ketogenesis processes to restore BBB integrity after stroke. Ketogenesis functions as an early metabolic responder to restrain stroke progression, providing novel prospectives for clinical translation.

Associations between admission levels of multiple biomarkers and subsequent worse outcomes in acute ischemic stroke patients

The modified Rankin Scale change score (ΔmRS) is useful for evaluating acute poststroke functional improvement or deterioration. We investigated the relationship between multiple biomarkers and ΔmRS by analyzing data on 6931 patients with acute ischemic stroke (average age 62.3 ± 11.3 years, 2174 (31.4%) female) enrolled from the Third China National Stroke Registry (CNSR-III) and 15 available biomarkers. Worse outcomes at 3 months were defined as ΔmRS3m-discharge ≥1 (ΔmRS3m-discharge = mRS3m-mRSdischarge). Adjusted odds ratios (aORs) and their 95% confidence intervals (CIs) were calculated from logistic regression models. At 3-months poststroke, 1026 (14.8%) patients experienced worse outcomes. The highest quartiles of white blood cells (WBCs) (aOR [95%CI],1.37 [1.12-1.66]), high-sensitivity C-reactive protein (hs-CRP) (1.37 [1.12-1.67]), interleukin-6 (IL-6) (1.43 [1.16-1.76]), interleukin-1 receptor antagonist (IL-1Ra) (1.46 [1.20-1.78]) and YKL-40 (1.31 [1.06-1.63]) were associated with an increased risk of worse outcomes at 3 months. Results remained stable except for YKL-40 when simultaneously adding multiple biomarkers to the basic traditional-risk-factor model. Similar results were observed at 6 and 12 months after stroke. This study indicated that WBCs, hs-CRP, IL-6, IL-1Ra, and YKL-40 were significantly associated with worse outcomes in acute ischemic stroke patients, and all inflammatory biomarkers except YKL-40 were independent predictors of worse outcomes at 3 months.

Association of the Neutrophil-to-Lymphocyte Ratio with 90-Day Functional Outcomes in Patients with Acute Ischemic Stroke

The neutrophil-to-lymphocyte ratio (NLR), an inflammatory marker, plays an important role in the inflammatory mechanisms of the pathophysiology and progression of acute ischemic stroke (AIS). The aim of this study was to identify the potential factors associated with functional prognosis in AIS. A total of 303 AIS patients were enrolled in this study; baseline information of each participant, including demographic characteristics, medical history, laboratory data, and 90-day functional outcome, was collected. Multivariate logistic regression analysis revealed that NLR, systolic blood pressure (SBP) and National Institutes of Health Stroke Scale (NIHSS) score were found to be independent factors for poor functional outcomes. Receiver operating characteristic (ROC) curve analysis was performed to estimate the predictive value of the NLR for 90-day functional outcome, with the best predictive cutoff value being 3.06. In the multivariate logistic regression analysis, three models were constructed: Model 1, adjusted for age, sex, SBP, and TOAST classification (AUC = 0.694); Model 2, further adjusted for the NIHSS score at admission (AUC = 0.826); and Model 3, additionally adjusted for the NLR (AUC = 0.829). The NLR at admission was an independent predictor of 90-day prognosis in patients with AIS. The risk factors related to poor 90-day functional outcomes were higher SBP, higher NLR, and a greater NIHSS score.

One-Year Disability Trajectories and Long-Term Cardiovascular Events, Recurrent Stroke, and Mortality After Ischemic Stroke

BACKGROUND

Patients with stroke are often affected by varying degrees of functional disability and have different evolution patterns in functional disability. However, little is known about the predictive usefulness of disability changes after stroke. We aimed to describe 1-year disability trajectories and to assess the associations of longitudinal disability trajectories with 24-month clinical outcomes after ischemic stroke.

METHODS AND RESULTS

A total of 3533 patients with ischemic stroke from CATIS (China Antihypertensive Trial in Acute Ischemic Stroke) were studied. Distinct trajectories of disability were identified by the group-based trajectory model, as measured by modified Rankin Scale score within 12 months. Cox proportional hazards regression models were used to examine the associations of disability trajectories with 24-month cardiovascular events and all-cause mortality. We identified 4 distinct disability trajectories: no significant disability (562 participants [15.9%]), slight disability to recovery (1575 participants [44.6%]), severe to moderate disability (1087 participants [30.8%]), and persistent severe disability (309 participants [8.7%]). Compared with no significant disability trajectory, the multivariable adjusted hazard ratios (95% CIs) of patients within the persistent heavy-severe trajectory were 2.63 (1.20-5.76) for cardiovascular events, 2.55 (1.12-5.79) for recurrent stroke, and 6.10 (2.22-16.72) for all-cause mortality; notably, the hazard ratios (95% CIs) for patients within the severe to moderate disability trajectory were 1.99 (1.01-3.94) for cardiovascular events and 1.85 (1.03-3.33) for the composite outcome of cardiovascular events and all-cause mortality.

CONCLUSIONS

Functional disability trajectories within 12 months after stroke onset were associated with the risk of 24-month adverse outcomes. Patients with persistent severe disability or severe to moderate disability had higher risk of cardiovascular events and all-cause mortality.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT01840072.

CSF-Based Volumetric Imaging Biomarkers Highlight Incidence and Risk Factors for Cerebral Edema After Ischemic Stroke

BACKGROUND

Cerebral edema has primarily been studied using midline shift or clinical deterioration as end points, which only captures the severe and delayed manifestations of a process affecting many patients with stroke. Quantitative imaging biomarkers that measure edema severity across the entire spectrum could improve its early detection, as well as identify relevant mediators of this important stroke complication.

METHODS

We applied an automated image analysis pipeline to measure the displacement of cerebrospinal fluid (ΔCSF) and the ratio of lesional versus contralateral hemispheric cerebrospinal fluid (CSF) volume (CSF ratio) in a cohort of 935 patients with hemispheric stroke with follow-up computed tomography scans taken a median of 26 h (interquartile range 24-31) after stroke onset. We determined diagnostic thresholds based on comparison to those without any visible edema. We modeled baseline clinical and radiographic variables against each edema biomarker and assessed how each biomarker was associated with stroke outcome (modified Rankin Scale at 90 days).

RESULTS

The displacement of CSF and CSF ratio were correlated with midline shift (r = 0.52 and - 0.74, p < 0.0001) but exhibited broader ranges. A ΔCSF of greater than 14% or a CSF ratio below 0.90 identified those with visible edema: more than half of the patients with stroke met these criteria, compared with only 14% who had midline shift at 24 h. Predictors of edema across all biomarkers included a higher National Institutes of Health Stroke Scale score, a lower Alberta Stroke Program Early CT score, and lower baseline CSF volume. A history of hypertension and diabetes (but not acute hyperglycemia) predicted greater ΔCSF but not midline shift. Both ΔCSF and a lower CSF ratio were associated with worse outcome, adjusting for age, National Institutes of Health Stroke Scale score, and Alberta Stroke Program Early CT score (odds ratio 1.7, 95% confidence interval 1.3-2.2 per 21% ΔCSF).

CONCLUSIONS

Cerebral edema can be measured in a majority of patients with stroke on follow-up computed tomography using volumetric biomarkers evaluating CSF shifts, including in many without visible midline shift. Edema formation is influenced by clinical and radiographic stroke severity but also by chronic vascular risk factors and contributes to worse stroke outcomes.

Speech-language pathologists' perspectives of dysphagia following reperfusion therapies: An Australian mixed-methods study

PURPOSE

To investigate speech-language pathologists' (SLPs) perceptions and clinical experiences of dysphagia management following reperfusion therapies.

METHOD

A multi-staged mixed approach involving a two-phase cross-sectional design was used. Data generated during phase 1 (a purpose-built, online survey) guided the development of phase 2 (semi-structured interviews). Sixty-two SLPs participated in phase 1 and six SLPs participated in phase 2.

RESULT

SLPs in both phases reported perceived changes in dysphagia presentation according to the success of reperfusion therapy administered and had concerns regarding worsened dysphagia following unsuccessful procedures. Fluctuations in dysphagia were more frequently reported in the acute stage post-stroke. SLPs reported increased workload demands due to increased interhospital transfers between ECR/thrombolysis centres and referring facilities. The optimal timing for swallowing screening and assessment was not identified, with initial SLP involvement ranging from during the administration of thrombolysis to up to 24 hours post-reperfusion therapy.

CONCLUSION

Preliminary evidence suggests that SLPs perceive that the presentation of post-stroke dysphagia is changing, with increasing fluctuations and complexities in the acute stage of post-stroke care, within the context of increasing use of reperfusion therapies. There is a critical need for research investigating the trajectory of dysphagia in the acute stage to inform dysphagia management within this patient population.

The relationship between neurological function trajectory, assessed by repeated NIHSS measurement, and long-term cardiovascular events, recurrent stroke, and mortality after ischemic stroke

BACKGROUND

Clinically significant changes in neurological deficits frequently occur after stroke onset, reflecting further neurological injury or neurological improvement. However, the National Institutes of Health Stroke Scale (NIHSS) score is only evaluated once in most studies, usually at stroke onset. Utilizing repeated measures of NIHSS scores to identify different trajectories of neurological function may be more informative and provide more useful predictive information. We determined the association of neurological function trajectories with long-term clinical outcomes after ischemic stroke.

METHODS

A total of 4025 participants with ischemic stroke from the China Antihypertensive Trial in Acute Ischemic Stroke were included. Patients were recruited from 26 hospitals across China between August 2009 and May 2013. A group-based trajectory model was used to identify distinct neurological function trajectories, as measured by NIHSS at admission, 14 days or hospital discharge, and 3 months. Study outcomes were cardiovascular events, recurrent stroke, and all-cause mortality during 3-24 months after ischemic stroke onset. Cox proportional hazards models were used to examine the associations of neurological function trajectories with outcomes.

RESULTS

We identified three distinct subgroups of NIHSS trajectories: persistent severe (persistent high NIHSS scores during the 3-month follow-up), moderate (NIHSS scores started at around 5 and gradually reduced), and mild (NIHSS scores always below 2). The three trajectory groups had different clinical profiles and different risk of stroke outcomes at 24-month follow-up. Compared to the mild trajectory group, patients in the persistent severe trajectory group had a higher risk of cardiovascular events (multivariable-adjusted hazard ratios (95% confidence intervals) = 1.77 (1.10-2.86)), recurrent stroke (1.82 (1.10-3.00)), and all-cause mortality (5.64 (3.37-9.43)). Those with moderate trajectory had an intermediate risk: 1.45 (1.03-2.04) for cardiovascular events and 1.52 (1.06-2.19) for recurrent stroke.

CONCLUSION

Longitudinal neurological function trajectories derived from repeated NIHSS measurements during the first 3 months after stroke provide additional predictive information and are associated with long-term clinical outcomes. The trajectories characterized by persistent severe and moderate neurological impairment were associated with increased risk of subsequent cardiovascular events.

Post-thrombolysis early neurological deterioration occurs with or without hemorrhagic transformation in acute cerebral infarction: risk factors, prediction model and prognosis

Objectives

Early neurological deterioration (END) after ischemic stroke is a severe clinical event and can be caused by hemorrhagic and ischemic injury. We studied the difference between the risk factors of END occurs with or without hemorrhagic transformation after intravenous thrombolysis.

Materials and methods

Consecutive cerebral infarction patients who underwent intravenous thrombolysis from 2017 to 2020 in our hospital were retrospectively recruited. END was defined as a ≥2 points increase on 24-h National Institutes of Health Stroke Scale (NIHSS) score after therapy compared with the best neurological status after thrombolysis and divided into two types based on the computed tomography (CT): symptomatic intracranial hemorrhage (ENDh) and non-hemorrhagic factors (ENDn). Potential risk factors of ENDh and ENDn were assessed by multiple logistic regression and applied to establish the prediction model.

Results

A total of 195 patients were included. In multivariate analysis, the previous history of cerebral infarction (odds ratio [OR],15.19; 95% confidence interval [CI],1.43-161.17; P = 0.025), previous history of atrial fibrillation (OR,8.43; 95%CI,1.09-65.44; P = 0.043), higher baseline NIHSS score (OR,1.19; 95%CI,1.03-1.39; P = 0.022) and higher alanine transferase level (OR,1.05; 95%CI, 1.01-1.10; P = 0.016) were independently associated with ENDh. While higher systolic blood pressure (OR,1.03; 95%CI,1.01-1.05; P = 0.004), higher baseline NIHSS score (OR,1.13; 95%CI,2.86-27.43; P < 0.000) and large artery occlusion (OR,8.85, 95%CI,2.86-27.43; P < 0.000) were independent risk factors of ENDn. The prediction model showed good specificity and sensitivity in predicting the risk of ENDn.

Conclusions

There are differences between the major contributors to ENDh and ENDn, while a severe stroke can increase the occurrence of both sides.

TICI-RANKIN mismatch: Poor clinical outcome despite complete endovascular reperfusion in the ETIS Registry

INTRODUCTION

Endovascular treatment (EVT) is a well-established technic for acute ischemic stroke, but despite a high recanalization rate of near 80%, at 3 months roughly 50% of patients have a poor functional outcome with a modified Rankin score (mRS) ≥3. The aim of this study was to determine predictive factors of poor functional outcomes in patients with complete recanalization after EVT, defined as modified thrombolysis in cerebral infarction (mTICI) 3.

PATIENTS AND METHODS

This retrospective analysis based on the prospective multicenter ETIS registry (endovascular treatment in ischemic stroke) in France included 795 patients from January 2015 and November 2019 with acute ischemic stroke due to anterior circulation occlusion and prestroke mRS 0-1, treated with EVT and who achieved complete recanalization. Univariate and multivariate logistic regression models were used to identify predictive factors of poor functional outcome.

RESULTS

365 patients (46%) showed a poor functional outcome (mRS>2). In backward-stepwise logistic regression analysis, poor functional outcome was independently associated with older age (OR per 10-year increase, 1.51; 95%CI, 1.30 to 1.75), higher admission NIHSS (OR per 1 point increase, 1.28; 95%CI, 1.21 to 1.34), absence of prior intravenous thrombolysis (OR, 0.59; 95%CI, 0.39 to 0.90), and an unfavorable 24-hour NIHSS change (24h-baseline) (OR, 0.82; 95%CI, 0.79 to 0.87). We calculated that patients whose 24h NIHSS decreased by less than 5 points are more at risk of a poor outcome, with a sensitivity and a specificity of 65.0%.

CONCLUSION

Despite complete reperfusion after EVT, half of patients had a poor clinical outcome. These patients, who were mainly older with a high initial NIHSS and an unfavorable post-EVT 24h NIHSS change, could represent a target population for early neurorepair and neurorestorative strategies.

Can chronic kidney disease staging early predict outcome of large-artery ischemic stroke with impaired renal function?

Background

Ischemic stroke poses a major threat to human beings, and a prompt intravenous thrombolytic management remains the gold standard protocol for stroke sufferers. Although the role of thrombolytic therapy (r-tPA) for ischemic stroke patients and those with underlying impaired renal function has been advocated as effective treating strategy, there is still a lack of investigation as to finding out baseline important variables that are capable of early outcome prediction.

Objectives

In this project, we hypothesize that the change of clinical chronic kidney disease (CKD) staging (delta stage = CKD stage after 3-month follow-up - CKD stage at admission) could serve as a crucial predictor of the prognosis of patients.

Design

This is a cohort longitudinal retrospective study.

Sources and Methods

A total of 765 cerebral artery ischemic stroke patients with impaired renal function were recruited and followed up for 1 year. Among them, 116 had received the thrombolytic treatment (r-tPA) after being evaluated at the triage in the emergency department and the rest had not (non-r-tPA). Propensity-matching was applied to compare the mortality between the r-tPA and non-r-tPA groups. Multiple logistic regression (LR) and decision tree (DT) algorithm were used to identify important prediction factors for mortality as well as the improvement in neurological function.

Results

The 1-year mortality rates for r-tPA and non-r-tPA groups were 32.8% and 44.4%, respectively. The propensity-matched odds ratio of mortality for the r-tPA group compared with the non-r-tPA group is 0.469, with p = 0.003. Logistic regressions suggest that age, Hct, diabetes mellitus type 2, coronary artery disease, and delta stage are important factors for mortality for the non-r-tPA group, whereas age, diabetes mellitus type 2, chronic heart failure, hospital day, and delta stage are important factors for the r-tPA group. On the usage of antihypertensive drugs, ACEI/ARB was not associated with mortality (p = 0.198), whereas the diuretic was, with odds ratio at 1.619 (p = 0.025), indicating higher mortality after administration. Both LR and DT analyses indicate that delta stage is the most important predictor. For the r-tPA group, patients with delta stage ⩽0 had a 24% mortality, while that for delta stage >0 the mortality is 75%. For non-r-tPA patients, the corresponding mortalities were 30.9 and 66.3, respectively. Delta stage is also useful for predicting patients' improvement of neurological function, assessed by NIHSS, mRS, and Barthel Index. The areas under the curve for the three assessments are 0.83, 0.835, and 0.663, respectively.

Conclusion

Large-artery ischemic stroke patients who received thrombolytic treatment had significantly lower mortality, even when presenting underlying impaired renal function. The change of CKD staging (delta stage) is capable of acting as a powerful clinical baseline surrogate for both r-tPA and non-r-tPA patients in terms of early outcome prediction. Long-term use of diuretics could be potentially harmful to this group of patients. Moreover, delta stage correlates well with clinical long-term neurological functionality assessment (NIHSS, mRS, and Barthel index), which is helpful in aiding urgent clinical decision-making.

Radiomics Analysis of Diffusion-Weighted Imaging and Long-Term Unfavorable Outcomes Risk for Acute Stroke

BACKGROUND

Diffusion-weighted imaging radiomics could be used as prognostic biomarkers in acute ischemic stroke. We aimed to identify a clinical and diffusion-weighted imaging radiomics model for individual unfavorable outcomes risk assessment in acute ischemic stroke.

METHODS

A total of 1716 patients with acute ischemic stroke from 2 centers were divided into a training cohort and a validation cohort. Patient outcomes were measured with the modified Rankin Scale score. An unfavorable outcome was defined as a modified Rankin Scale score greater than 2. The primary end point was all-cause mortality or outcomes 1 year after stroke. The MRI-DRAGON score was calculated based on previous publications. We extracted and selected the infarct features on diffusion-weighted imaging to construct a radiomic signature. The clinic-radiomics signature was built by measuring the Cox proportional risk regression score (CrrScore) and compared with the MRI-DRAGON score and the ClinicScore. CrrScore model performance was estimated by 1-year unfavorable outcomes prediction.

RESULTS

A high radiomic signature predicted a higher probability of unfavorable outcomes than a low radiomic signature in the training (hazard ratio, 3.19 [95% CI, 2.51-4.05]; P<0.0001) and validation (hazard ratio, 3.25 [95% CI, 2.20-4.80]; P<0.0001) cohorts. The diffusion-weighted imaging Alberta Stroke Program Early CT Score, age, glucose level before therapy, National Institutes of Health Stroke Scale score on admission, glycated hemoglobin' radiomic signature, hemorrhagic infarction, and malignant cerebral edema were associated with an unfavorable outcomes risk after multivariable adjustment. A CrrScore nomogram was developed to predict outcomes and had the best performance in the training (area under the curve, 0.862) and validation cohorts (area under the curve, 0.858). The CrrScore model time-dependent areas under the curve of the probability of unfavorable outcomes at 1 year in the training and validation cohorts were 0.811 and 0.801, respectively.

CONCLUSIONS

The CrrScore model allows the accurate prediction of patients with acute ischemic stroke outcomes and can potentially guide rehabilitation therapies for patients with different risks of unfavorable outcomes.

Location-weighted versus Volume-weighted Mismatch at MRI for Response to Mechanical Thrombectomy in Acute Stroke

Background A target mismatch profile can identify good clinical response to recanalization after acute ischemic stroke, but does not consider region specificities. Purpose To test whether location-weighted infarction core and mismatch, determined from diffusion and perfusion MRI performed in patients with acute stroke, could improve prediction of good clinical response to mechanical thrombectomy compared with a target mismatch profile. Materials and Methods In this secondary analysis, two prospectively collected independent stroke data sets (2012-2015 and 2017-2019) were analyzed. From the brain before stroke (BBS) study data (data set 1), an eloquent map was computed through voxel-wise associations between the infarction core (based on diffusion MRI on days 1-3 following stroke) and National Institutes of Health Stroke Scale (NIHSS) score. The French acute multimodal imaging to select patients for mechanical thrombectomy (FRAME) data (data set 2) consisted of large vessel occlusion-related acute ischemic stroke successfully recanalized. From acute MRI studies (performed on arrival, prior to thrombectomy) in data set 2, target mismatch and eloquent (vs noneloquent) infarction core and mismatch were computed from the intersection of diffusion- and perfusion-detected lesions with the coregistered eloquent map. Associations of these imaging metrics with early neurologic improvement were tested in multivariable regression models, and areas under the receiver operating characteristic curve (AUCs) were compared. Results Data sets 1 and 2 included 321 (median age, 69 years [IQR, 58-80 years]; 207 men) and 173 (median age, 74 years [IQR, 65-82 years]; 90 women) patients, respectively. Eloquent mismatch was positively and independently associated with good clinical response (odds ratio [OR], 1.14; 95% CI: 1.02, 1.27; P = .02) and eloquent infarction core was negatively associated with good response (OR, 0.85; 95% CI: 0.77, 0.95; P = .004), while noneloquent mismatch was not associated with good response (OR, 1.03; 95% CI: 0.98, 1.07; P = .20). Moreover, adding eloquent metrics improved the prediction accuracy (AUC, 0.73; 95% CI: 0.65, 0.81) compared with clinical variables alone (AUC, 0.65; 95% CI: 0.56, 0.73; P = .01) or a target mismatch profile (AUC, 0.67; 95% CI: 0.59, 0.76; P = .03). Conclusion Location-weighted infarction core and mismatch on diffusion and perfusion MRI scans improved the identification of patients with acute stroke who would benefit from mechanical thrombectomy compared with the volume-based target mismatch profile. Clinical trial registration no. NCT03045146 © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Nael in this issue.

7-Day National Institutes of Health Stroke Scale as a surrogate marker predicting ischemic stroke patients' outcome following endovascular therapy

Background

Early neurological deterioration after endovascular thrombectomy (EVT) is associated with poor prognosis. National Institutes of Health Stroke Scale (NIHSS) score measured at 24 h after EVT may be a better outcome predictor than other methods that focus on changes in NIHSS. Nevertheless, clinical fluctuations in ischemic stroke patients during the immediate phase after symptoms onset are well recognized. Therefore, a delayed NIHSS evaluation may improve prognostic accuracy. We evaluate the 7-day NIHSS in predicting long-term patient outcomes after EVT.

Methods

This was a multi-center retrospective cohort study of 300 consecutive ischemic stroke patients with large vessel occlusion who underwent EVT at three-stroke centers in China from August 2018 to March 2022. NIHSS was recorded on admission, pre-EVT, 24 h, and 7 days after EVT.

Results

A total of 236 eligible patients were subdivided into two groups: 7-day NIHSS ≤6 and NIHSS >6 post-EVT. 88.29% achieved a favorable outcome (modified Rankin Scale 0-2) in the NIHSS ≤6 group compared to 15.20% in the NIHSS >6 group at 90 days, and an improved favorable outcome in the former group was observed after adjusting for potential confounding factors (adjusted odds ratio 39.7, 95% confidence interval, 17.5-89.7, p < 0.001).

Conclusion

The 7-day NIHSS score may be a reliable predictor of 90-day stroke patient outcome after EVT.

Arrival time at a referral hospital and functional disability of people with stroke: a cohort study

BACKGROUND

Stroke is a major cause of death and functional disability worldwide. Knowledge of the associated factors is essential for defining education, management, and healthcare strategies.

OBJECTIVE

To analyze the association between arrival time at a neurology referral hospital (ATRH) and functional disability in patients with ischemic stroke 90 days after the event.

DESIGN AND SETTING

Prospective cohort study conducted at a public institution of higher education in Brazil.

METHODS

This study included 241 people aged ≥ 18 years who presented ischemic stroke. The exclusion criteria were death, inability to communicate without companions who could answer the research questions, and > 10 days since ictus. Disability was assessed using the Rankin score (mR). Variables for which associations showed a P value ≤ 0.20 in bivariate analysis were tested as modifiers between ATRH and disability. Significant interaction terms were used for multivariate analysis. Multivariate logistic regression analysis was performed with all variables, arriving at the complete model and adjusted beta measures. The confounding variables were included in the robust logistic regression model, and Akaike's Information Criterion was adopted to choose the final model. The Poisson model assumes a statistical significance of 5% and risk correction.

RESULTS

Most participants (56.0%) arrived at the hospital within 4.5 hours of symptom onset, and 51.7% presented with mRs of 3 to 5 after 90 days of ictus. In the multivariate model, ATRH ≥ 4.5 hours and females were associated with more significant disability.

CONCLUSIONS

Arrival at the referral hospital 4.5 hours after the onset of symptoms or wake-up stroke was an independent predictor of a high degree of functional disability.

Study protocol of Branch Atheromatous Disease-related stroke (BAD-study): a multicenter prospective cohort study

BACKGROUND

As a meaningful subtype of ischemic stroke in Asians, Branch atheromatous disease (BAD)-related stroke is associated with high early neurological deterioration (END) and disability, but is understudied and without recommended therapy. The mechanism of END still remains unclear. Branch atheromatous disease-related stroke study (BAD-study) therefore aims to investigate demographic, clinical and radiological features, and prognosis of BAD-related stroke in Chinese patients.

METHODS/DESIGN

BAD-study is a nationwide, multicenter, consecutive, prospective, observational cohort study enrolling patients aged 18-80 years with BAD-related stroke within 72 h after symptom onset. Initial clinical data, laboratory tests, and imaging data are collected via structured case report form, and follow-ups will be performed at 7 days, 30 days, 90 days, 6 months and 12 months after enrollment. The primary outcome is the score on modified Rankin Scale at 90-day follow-up with single-blinded assessment. Secondary outcomes include END within 7 days, and National institute of health stroke scale score, Barthel index, cerebrovascular events, major bleeding complications, and all-cause mortality during 90-day follow-up. Characteristics of penetrating and parent artery will be assessed by high-resolution magnetic resonance imaging combined with other imaging techniques.

DISCUSSION

BAD-study can provide demographic, clinical, radiological, and prognostic characteristics of BAD-related stroke, and thereby potentially figure out the vascular mechanism of early neurological deterioration and optimize therapy strategy with the aid of advanced imaging technique. Baseline data and evidence will also be generated for randomized controlled trials on BAD-related stroke in the future.

Quantitative collateral score for the prediction of clinical outcomes in stroke patients: Better than visual grading

Objectives

To identify preoperative prognostic factors for acute ischemic stroke (AIS) patients receiving mechanical thrombectomy (MT) and compare the performance of quantitative collateral score (qCS) and visual collateral score (vCS) in outcome prediction.

Methods

Fifty-five patients with AIS receiving MT were retrospectively enrolled. qCS was defined as the percentage of the volume of collaterals of both hemispheres. Based on the dichotomous outcome assessed using a 90-day modified Rankin Scale (mRS), we compared qCS, vCS, age, sex, National Institute of Health stroke scale score, etiological subtype, platelet count, international normalized ratio, glucose levels, and low-density lipoprotein cholesterol (LDL-C) levels between favorable and unfavorable outcome groups. Logistic regression analysis was performed to determine the effect on the clinical outcome. The discriminatory power of qCS, vCS, and their combination with cofounders for determining favorable outcomes was tested with the area under the receiver-operating characteristic curve (AUC).

Results

vCS, qCS, LDL-C, and age could all predict clinical outcomes. qCS is superior over vCS in predicting favorable outcomes with a relatively higher AUC value (qCS vs. vCS: 0.81 vs. 0.74) and a higher sensitivity rate (qCS vs. vCS: 72.7% vs. 40.9%). The prediction power of qCS + LDL-C + age was best with an AUC value of 0.91, but the accuracy was just increased slightly compared to that of qCS alone.

Conclusion

Collateral scores, LDL-C and age were independent prognostic predictors for patients with AIS receiving MT; qCS was a better predictor than vCS. Furthermore, qCS + LDL-C + age offers a strong prognostic prediction power and qCS alone was another good choice for predicting clinical outcome.

Altered methylation pattern in EXOC4 is associated with stroke outcome: an epigenome-wide association study

BACKGROUND AND PURPOSE

The neurological course after stroke is highly variable and is determined by demographic, clinical and genetic factors. However, other heritable factors such as epigenetic DNA methylation could play a role in neurological changes after stroke.

METHODS

We performed a three-stage epigenome-wide association study to evaluate DNA methylation associated with the difference between the National Institutes of Health Stroke Scale (NIHSS) at baseline and at discharge (ΔNIHSS) in ischaemic stroke patients. DNA methylation data in the Discovery (n = 643) and Replication (n = 62) Cohorts were interrogated with the 450 K and EPIC BeadChip. Nominal CpG sites from the Discovery (p value < 10-06) were also evaluated in a meta-analysis of the Discovery and Replication cohorts, using a random-fixed effect model. Metabolic pathway enrichment was calculated with methylGSA. We integrated the methylation data with 1305 plasma protein expression levels measured by SOMAscan in 46 subjects and measured RNA expression with RT-PCR in a subgroup of 13 subjects. Specific cell-type methylation was assessed using EpiDISH.

RESULTS

The meta-analysis revealed an epigenome-wide significant association in EXOC4 (p value = 8.4 × 10-08) and in MERTK (p value = 1.56 × 10-07). Only the methylation in EXOC4 was also associated in the Discovery and in the Replication Cohorts (p value = 1.14 × 10-06 and p value = 1.3 × 10-02, respectively). EXOC4 methylation negatively correlated with the long-term outcome (coefficient = - 4.91) and showed a tendency towards a decrease in EXOC4 expression (rho = - 0.469, p value = 0.091). Pathway enrichment from the meta-analysis revealed significant associations related to the endocytosis and deubiquitination processes. Seventy-nine plasma proteins were differentially expressed in association with EXOC4 methylation. Pathway analysis of these proteins showed an enrichment in natural killer (NK) cell activation. The cell-type methylation analysis in blood also revealed a differential methylation in NK cells.

CONCLUSIONS

DNA methylation of EXOC4 is associated with a worse neurological course after stroke. The results indicate a potential modulation of pathways involving endocytosis and NK cells regulation.

Genome-Wide Studies in Ischaemic Stroke: Are Genetics Only Useful for Finding Genes?

Ischaemic stroke is a complex disease with some degree of heritability. This means that heritability factors, such as genetics, could be risk factors for ischaemic stroke. The era of genome-wide studies has revealed some of these heritable risk factors, although the data generated by these studies may also be useful in other disciplines. Analysis of these data can be used to understand the biological mechanisms associated with stroke risk and stroke outcome, to determine the causality between stroke and other diseases without the need for expensive clinical trials, or to find potential drug targets with higher success rates than other strategies. In this review we will discuss several of the most relevant studies regarding the genetics of ischaemic stroke and the potential use of the data generated.

Stroke recovery phenotyping through network trajectory approaches and graph neural networks

Stroke is a leading cause of neurological injury characterized by impairments in multiple neurological domains including cognition, language, sensory and motor functions. Clinical recovery in these domains is tracked using a wide range of measures that may be continuous, ordinal, interval or categorical in nature, which can present challenges for multivariate regression approaches. This has hindered stroke researchers’ ability to achieve an integrated picture of the complex time-evolving interactions among symptoms. Here, we use tools from network science and machine learning that are particularly well-suited to extracting underlying patterns in such data, and may assist in prediction of recovery patterns. To demonstrate the utility of this approach, we analyzed data from the NINDS tPA trial using the Trajectory Profile Clustering (TPC) method to identify distinct stroke recovery patterns for 11 different neurological domains at 5 discrete time points. Our analysis identified 3 distinct stroke trajectory profiles that align with clinically relevant stroke syndromes, characterized both by distinct clusters of symptoms, as well as differing degrees of symptom severity. We then validated our approach using graph neural networks to determine how well our model performed predictively for stratifying patients into these trajectory profiles at early vs. later time points post-stroke. We demonstrate that trajectory profile clustering is an effective method for identifying clinically relevant recovery subtypes in multidimensional longitudinal datasets, and for early prediction of symptom progression subtypes in individual patients. This paper is the first work introducing network trajectory approaches for stroke recovery phenotyping, and is aimed at enhancing the translation of such novel computational approaches for practical clinical application.

Use of Machine Learning Algorithms to Predict the Outcomes of Mechanical Thrombectomy in Acute Ischemic Stroke Patients With an Extended Therapeutic Time Window

OBJECTIVE

The aim of this study was to evaluate the performance of machine learning (ML) algorithms in predicting the functional outcome of mechanical thrombectomy (MT) outside the 6-hour therapeutic time window in patients with acute ischemic stroke (AIS).

METHODS

One hundred seventy-seven consecutive AIS patients with large-vessel occlusion in the anterior circulation who underwent MT in the extended time window were enrolled. Clinical, neuroimaging, and treatment variables that could be obtained quickly in the real-world emergency settings were collected. Four machine learning algorithms (random forests, regularized logistic regression, support vector machine, and naive Bayes) were used to predict good outcomes (modified Rankin Scale scores of 0-2) at 90 days by using (1) only variables at admission and (2) both baseline and treatment variables. The performance of each model was evaluated using receiver operating characteristic (ROC) curve analysis. Feature importance was ranked using random forest algorithms.

RESULTS

Eighty patients (45.2%) had a favorable 90-day outcome. Machine learning models including baseline clinical and neuroimaging characteristics predicted 90-day modified Rankin Scale with an area under the ROC curve of 0.80-0.81, sensitivity of 0.60-0.71 and specificity of 0.71-0.76. Further inclusion the treatment variables significantly improved the predictive performance (mean area under the ROC curve, 0.89-0.90; sensitivity, 0.77-0.85; specificity, 0.75-0.87). The most important characteristics for predicting 90-day outcomes were age, hypoperfusion intensity ratio at admission, and National Institutes of Health Stroke Scale score at 24 hours after MT.

CONCLUSIONS

Machine learning algorithms may facilitate prediction of 90-day functional outcomes in AIS patients with an extended therapeutic time window.

Favourable arterial, tissue-level and venous collaterals correlate with early neurological improvement after successful thrombectomy treatment of acute ischaemic stroke

BACKGROUND AND PURPOSE

Early neurological improvement (ENI) after thrombectomy is associated with better long-term outcomes in patients with acute ischaemic stroke due to large vessel occlusion (AIS-LVO). Whether cerebral collaterals influence the likelihood of ENI is poorly described. We hypothesised that favourable collateral perfusion at the arterial, tissue-level and venous outflow (VO) levels is associated with ENI after thrombectomy.

MATERIALS AND METHODS

Multicentre retrospective study of patients with AIS-LVO treated by thrombectomy. Tissue-level collaterals (TLC) were measured on cerebral perfusion studies by the hypoperfusion intensity ratio. VO and pial arterial collaterals (PAC) were determined by the Cortical Vein Opacification Score and the modified Tan scale on CT angiography, respectively. ENI was defined as improvement of ≥8 points or a National Institutes of Health Stroke Scale score of 0 hour or 1 24 hours after treatment. Multivariable regression analyses were used to determine the association of collateral biomarkers with ENI and good functional outcomes (modified Rankin Scale 0-2).

RESULTS

646 patients met inclusion criteria. Favourable PAC (OR: 1.9, CI 1.2 to 3.1; p=0.01), favourable VO (OR: 3.3, CI 2.1 to 5.1; p<0.001) and successful reperfusion (OR: 3.1, CI 1.7 to 5.8; p<0.001) were associated with ENI, but favourable TLC were not (p=0.431). Good functional outcomes at 90-days were associated with favourable TLC (OR: 2.2, CI 1.4 to 3.6; p=0.001), VO (OR: 5.7, CI 3.5 to 9.3; p<0.001) and ENI (OR: 5.7, CI 3.3 to 9.8; p<0.001), but not PAC status (p=0.647).

CONCLUSION

Favourable PAC and VO were associated with ENI after thrombectomy. Favourable TLC predicted longer term functional recovery after thrombectomy, but the impact of TLC on ENI is strongly dependent on vessel reperfusion.

External Validation of the Early Prediction of Functional Outcome After Stroke Prediction Model for Independent Gait at 3 Months After Stroke

Introduction

The Early Prediction of Functional Outcome after Stroke (EPOS) model for independent gait is a tool to predict between days 2 and 9 poststroke whether patients will regain independent gait 6 months after stroke. External validation of the model is important to determine its clinical applicability and generalizability by testing its performance in an independent cohort. Therefore, this study aimed to perform a temporal and geographical external validation of the EPOS prediction model for independent gait after stroke but with the endpoint being 3 months instead of the original 6 months poststroke.

Methods

Two prospective longitudinal cohort studies consisting of patients with first-ever stroke admitted to a Swiss hospital stroke unit. Sitting balance and strength of the paretic leg were tested at days 1 and 8 post-stroke in Cohort I and at days 3 and 9 in Cohort II. Independent gait was assessed 3 months after symptom onset. The performance of the model in terms of discrimination (area under the receiver operator characteristic (ROC) curve; AUC), classification, and calibration was assessed.

Results

In Cohort I [N = 39, median age: 74 years, 33% women, median National Institutes of Health Stroke Scale (NIHSS) 9], the AUC (95% confidence interval (CI)] was 0.675 (0.510, 0.841) on day 1 and 0.921 (0.811, 1.000) on day 8. For Cohort II (N = 78, median age: 69 years, 37% women, median NIHSS 8), this was 0.801 (0.684, 0.918) on day 3 and 0.846 (0.741, 0.951) on day 9.

Discussion and Conclusion

External validation of the EPOS prediction model for independent gait 3 months after stroke resulted in an acceptable performance from day 3 onward in mild-to-moderately affected patients with first-ever stroke without severe prestroke disability. The impact of applying this model in clinical practice should be investigated within this subgroup of patients with stroke. To improve the generalizability of patients with recurrent stroke and those with more severe, neurological comorbidities, the performance of the EPOS model within these patients should be determined across different geographical areas.

Inhibition of the enzyme autotaxin reduces cortical excitability and ameliorates the outcome in stroke

Stroke penumbra injury caused by excess glutamate is an important factor in determining stroke outcome; however, several therapeutic approaches aiming to rescue the penumbra have failed, likely due to unspecific targeting and persistent excitotoxicity, which continued far beyond the primary stroke event. Synaptic lipid signaling can modulate glutamatergic transmission via presynaptic lysophosphatidic acid (LPA) 2 receptors modulated by the LPA-synthesizing molecule autotaxin (ATX) present in astrocytic perisynaptic processes. Here, we detected long-lasting increases in brain ATX concentrations after experimental stroke. In humans, cerebrospinal fluid ATX concentration was increased up to 14 days after stroke. Using astrocyte-specific deletion and pharmacological inhibition of ATX at different time points after experimental stroke, we showed that inhibition of LPA-related cortical excitability improved stroke outcome. In transgenic mice and in individuals expressing a single-nucleotide polymorphism that increased LPA-related glutamatergic transmission, we found dysregulated synaptic LPA signaling and subsequent negative stroke outcome. Moreover, ATX inhibition in the animal model ameliorated stroke outcome, suggesting that this approach might have translational potential for improving the outcome after stroke.

National Institutes of Health Stroke Scale as an Outcome in Stroke Research: Value of ANCOVA Over Analyzing Change From Baseline

National Institutes of Health Stroke Scale (NIHSS), measured a few hours to days after stroke onset, is an attractive outcome measure for stroke research. NIHSS at the time of presentation (baseline NIHSS) strongly predicts the follow-up NIHSS. Because of the need to account for the baseline NIHSS in the analysis of follow-up NIHSS as an outcome measure, a common and intuitive approach is to define study outcome as the change in NIHSS from baseline to follow-up (ΔNIHSS). However, this approach has important limitations. Analyzing ΔNIHSS implies a very strong assumption about the relationship between baseline and follow-up NIHSS that is unlikely to be satisfied, drawing into question the validity of the resulting statistical analysis. This reduces the precision of the estimates of treatment effects and the power of clinical trials that use this approach to analysis. ANCOVA allows for the analysis of follow-up NIHSS as the dependent variable while adjusting for baseline NIHSS as a covariate in the model and addresses several challenges of using ΔNIHSS outcome using simple bivariate comparisons (eg, a t test, Wilcoxon rank-sum, linear regression without adjustment for baseline) for stroke research. In this article, we use clinical trial simulations to illustrate that variability in NIHSS outcome is less when follow-up NIHSS is adjusted for baseline compared to ΔNIHSS and how a reduction in this variability improves the power. We outline additional, important clinical and statistical arguments to support the superiority of ANCOVA using the final measurement of the NIHSS adjusted for baseline over, and caution against using, the simple bivariate comparison of absolute NIHSS change (ie, delta).

Multi-ancestry GWAS reveals excitotoxicity associated with outcome after ischaemic stroke

During the first hours after stroke onset, neurological deficits can be highly unstable: some patients rapidly improve, while others deteriorate. This early neurological instability has a major impact on long-term outcome. Here, we aimed to determine the genetic architecture of early neurological instability measured by the difference between the National Institutes of Health Stroke Scale (NIHSS) within 6 h of stroke onset and NIHSS at 24 h. A total of 5876 individuals from seven countries (Spain, Finland, Poland, USA, Costa Rica, Mexico and Korea) were studied using a multi-ancestry meta-analyses. We found that 8.7% of NIHSS at 24 h of variance was explained by common genetic variations, and also that early neurological instability has a different genetic architecture from that of stroke risk. Eight loci (1p21.1, 1q42.2, 2p25.1, 2q31.2, 2q33.3, 5q33.2, 7p21.2 and 13q31.1) were genome-wide significant and explained 1.8% of the variability suggesting that additional variants influence early change in neurological deficits. We used functional genomics and bioinformatic annotation to identify the genes driving the association from each locus. Expression quantitative trait loci mapping and summary data-based Mendelian randomization indicate that ADAM23 (log Bayes factor = 5.41) was driving the association for 2q33.3. Gene-based analyses suggested that GRIA1 (log Bayes factor = 5.19), which is predominantly expressed in the brain, is the gene driving the association for the 5q33.2 locus. These analyses also nominated GNPAT (log Bayes factor = 7.64) ABCB5 (log Bayes factor = 5.97) for the 1p21.1 and 7p21.1 loci. Human brain single-nuclei RNA-sequencing indicates that the gene expression of ADAM23 and GRIA1 is enriched in neurons. ADAM23, a presynaptic protein and GRIA1, a protein subunit of the AMPA receptor, are part of a synaptic protein complex that modulates neuronal excitability. These data provide the first genetic evidence in humans that excitotoxicity may contribute to early neurological instability after acute ischaemic stroke.

Hyperacute stroke thrombolysis via telemedicine: a multicentre study of performance, safety and clinical efficacy

OBJECTIVES

Timely thrombolysis of ischaemic stroke improves functional recovery, yet its delivery nationally is challenging due to shortages in the stroke specialist workforce and large geographical areas. One solution is remote stroke specialist input to regional centres via telemedicine. This study evaluates the usage and key metrics of performance of the East of England Stroke Telemedicine Partnership-the largest telestroke service in the UK-in providing hyperacute stroke care.

DESIGN

Prospective observational study.

SETTING

The East of England Stroke Telemedicine Partnership provides a horizontal 'hubless' model of out-of-hours hyperacute stroke care to a population of 6.2 million across a 7500 square mile semirural region.

PARTICIPANTS

All (2709) telestroke consultations between 1 January 2014 and 31 December 2019.

MAIN OUTCOME MEASURES

Thrombolysis decision, pre-thrombolysis and post-thrombolysis stroke severity (National Institutes of Health Stroke Scale, NIHSS), haemorrhagic complications, and hyperacute pathway timings.

RESULTS

Over the period, 1149 (42.4%) individuals were thrombolysed. Thrombolysis rates increased from 147/379 (38.8%) in 2014 to 225/490 (45.9%) in 2019. Median (IQR) pre-thrombolysis NIHSS was 10 (6-17), reducing to 6 (2-14) 24-hour post-thrombolysis (p<0.001). Post-thrombolysis haemorrhage occurred in 27 cases (2.3%). Over the period, median (IQR) door-to-needle time reduced from 85 (65-108) min to 68 (55-97.5) min (p<0.01), driven by improved imaging-to-needle times from 52.5 (38-72.25) min to 42 (30.5-62.5) min (p<0.01). However, the same period saw an increase in median onset-to-hospital arrival time from 77.5 (60-109.25) min to 95 (70-135) min (p<0.001).

CONCLUSIONS

The results from this large hyperacute telestroke cohort indicate two important points for clinical practice. First, telemedicine via a hubless horizontal model provides a clinically effective and safe method for delivering hyperacute stroke thrombolysis. Second, improved door-to-needle times were offset by a concerning rise in prehospital timings. These findings indicate that although telemedicine may benefit in-hospital hyperacute stroke care, improvements across the whole stroke pathway are essential.

Using Human Genetics to Understand Mechanisms in Ischemic Stroke Outcome: From Early Brain Injury to Long-Term Recovery

There is a critical need to elucidate molecular mechanisms underlying brain injury, repair, and recovery following ischemic stroke-a global health problem with major social and economic impact. Despite 5 decades of intensive research, there are no widely accepted neuroprotective drugs that mitigate ischemic brain injury, or neuroreparative drugs, or personalized approaches that guide therapies to enhance recovery. We here explore novel reverse translational approaches that will complement traditional forward translational methods in identifying mechanisms relevant to human stroke outcome. Although genome-wide association studies have yielded over 30 genetic loci that influence ischemic stroke risk, only a few genome-wide association studies have been performed for stroke outcome. We discuss important considerations for genetic studies of ischemic stroke outcome-including carefully designed phenotypes that capture injury/recovery mechanisms, anchored in time to stroke onset. We also address recent genome-wide association studies that provide insight into mechanisms underlying brain injury and repair. There are several ongoing initiatives exploring genomic associations with novel phenotypes related to stroke outcome. To improve the understanding of the genetic architecture of ischemic stroke outcome, larger studies using standardized phenotypes, preferably embedded in standard-of-care measures, are needed. Novel techniques beyond genome-wide association studies-including exploiting informatics, multi-omics, and novel analytics-promise to uncover genetic and molecular pathways from which drug targets and other new interventions may be identified.

The Stroke Neuro-Imaging Phenotype Repository: An Open Data Science Platform for Stroke Research

Stroke is one of the leading causes of death and disability worldwide. Reducing this disease burden through drug discovery and evaluation of stroke patient outcomes requires broader characterization of stroke pathophysiology, yet the underlying biologic and genetic factors contributing to outcomes are largely unknown. Remedying this critical knowledge gap requires deeper phenotyping, including large-scale integration of demographic, clinical, genomic, and imaging features. Such big data approaches will be facilitated by developing and running processing pipelines to extract stroke-related phenotypes at large scale. Millions of stroke patients undergo routine brain imaging each year, capturing a rich set of data on stroke-related injury and outcomes. The Stroke Neuroimaging Phenotype Repository (SNIPR) was developed as a multi-center centralized imaging repository of clinical computed tomography (CT) and magnetic resonance imaging (MRI) scans from stroke patients worldwide, based on the open source XNAT imaging informatics platform. The aims of this repository are to: (i) store, manage, process, and facilitate sharing of high-value stroke imaging data sets, (ii) implement containerized automated computational methods to extract image characteristics and disease-specific features from contributed images, (iii) facilitate integration of imaging, genomic, and clinical data to perform large-scale analysis of complications after stroke; and (iv) develop SNIPR as a collaborative platform aimed at both data scientists and clinical investigators. Currently, SNIPR hosts research projects encompassing ischemic and hemorrhagic stroke, with data from 2,246 subjects, and 6,149 imaging sessions from Washington University's clinical image archive as well as contributions from collaborators in different countries, including Finland, Poland, and Spain. Moreover, we have extended the XNAT data model to include relevant clinical features, including subject demographics, stroke severity (NIH Stroke Scale), stroke subtype (using TOAST classification), and outcome [modified Rankin Scale (mRS)]. Image processing pipelines are deployed on SNIPR using containerized modules, which facilitate replicability at a large scale. The first such pipeline identifies axial brain CT scans from DICOM header data and image data using a meta deep learning scan classifier, registers serial scans to an atlas, segments tissue compartments, and calculates CSF volume. The resulting volume can be used to quantify the progression of cerebral edema after ischemic stroke. SNIPR thus enables the development and validation of pipelines to automatically extract imaging phenotypes and couple them with clinical data with the overarching aim of enabling a broad understanding of stroke progression and outcomes.

International stroke genetics consortium recommendations for studies of genetics of stroke outcome and recovery

Numerous biological mechanisms contribute to outcome after stroke, including brain injury, inflammation, and repair mechanisms. Clinical genetic studies have the potential to discover biological mechanisms affecting stroke recovery in humans and identify intervention targets. Large sample sizes are needed to detect commonly occurring genetic variations related to stroke brain injury and recovery. However, this usually requires combining data from multiple studies where consistent terminology, methodology, and data collection timelines are essential. Our group of expert stroke and rehabilitation clinicians and researchers with knowledge in genetics of stroke recovery here present recommendations for harmonizing phenotype data with focus on measures suitable for multicenter genetic studies of ischemic stroke brain injury and recovery. Our recommendations have been endorsed by the International Stroke Genetics Consortium.

Stroke care in Italy at the time of the COVID-19 pandemic: a lesson to learn

From March to May 2020, the Italian health care system, as many others, was almost entirely devoted to the fight against the COVID-19 pandemic. In this context, a number of questions arose, from the increased stroke risk due to COVID-19 infection to the quality of stroke patient care. The overwhelming need of COVID-19 patient management made mandatory a complete re-organization of the stroke pathways: many health professionals were reallocated and a number of stroke units was turned into COVID-19 wards. As a result, acute stroke care suffered from a shortage of services and delays in time-dependent treatments and diagnostic work-up. In-patient and out-patient care and rehabilitation facilities for stroke survivors were also reduced or slowed down, to direct resources to COVID-19 patients care and to reduce contagion risks. Overall, this is likely to result in a significant future increased burden of complications and disabilities that will impact the health care systems in the coming months. Thus, while still fighting against COVID-19 disease, authorities need to promptly implement robust action plans, including an increase of workforce, without forgetting the assurance of a high level of stroke care. The medical community and the health care administrators should always keep in mind that stroke was before, and will be after the pandemic, a, sometimes, life-threatening condition, and almost always a disease with a severe impact on the quality of life.

Wake-up stroke: imaging-based diagnosis and recanalization therapy

Wake-up stroke (WUS) is a subgroup of ischemic stroke in which patients show no abnormality before sleep while wake up with neurological deficits. In addition to the uncertain onset, WUS patients have difficulty to receive prompt and effective thrombolytic or reperfusion therapy, leading to relatively poor prognosis. A number of researches have indicated that CT or MRI based thrombolysis and endovascular therapy might have benefits for WUS patients. This review article narratively discusses the pathogenesis, risk factors, imaging-based diagnosis and recanalization treatments of WUS with the purpose of expanding current treatment options for this group of stroke patients and exploring better therapeutic methods. The result showed that multimodal MRI or CT scan might be the best methods for extending the time window of WUS and, therefore, a large proportion of WUS patients could have favorable prognosis.