Conj Assoc Prof Carlos Garcia Esperon

Background: Posterior circulation infarction (POCI) is common. Imaging techniques such as non-contrast-CT (NCCT) and diffusion-weighted-magnetic-resonance-imaging commonly fail to detect hyperacute POCI. Studies suggest expert inspection of Computed Tomography Perfusion (CTP) improves diagnosis of POCI. In many settings, there is limited access to specialist expertise. Deep-learning has been successfully applied to automate imaging interpretation. This study aimed to develop and validate a deep-learning approach for the classification of POCI using CTP. Methods: Data were analysed from 3541-patients from the International-stroke-perfusion-registry (INSPIRE). All patients with baseline multimodal-CT and follow-up imaging performed at 24¿48 h were identified. A cohort of 541-patients was constructed on a 1:3 POCI-to -reference-ratio for model analysis. A 3D-Dense-Convolutional-Network (DenseNet) was trained to classify patients into POCI or non-POCI using CTP-deconvolved-maps. Six-stroke-experts also independently classified patients based upon stepwise access to multimodal CT (mCT) data. DenseNet results were compared against expert clinician results. Model and clinician performance was evaluated using area-under-the-receiver-operating-curve, sensitivity, specificity, accuracy and precision. Clinician agreement was measured with the Fleiss-Kappa-statistic. Results: Best mean clinician diagnostic accuracy, sensitivity and agreement was demonstrated after review of all mCT data (AUC: 0.81, Sensitivity: 0.65, Fleiss-Kappa-statistic: 0.73). There was a spectrum of individual clinician results with an AUC-range of 0.73¿0.86. Best DenseNet performance was recorded with an input combination of NCCT and delay-time maps. The DenseNet model was superior to the best mean clinician performance (AUC: 0.87) and was due to enhanced sensitivity (DenseNET: 0.77, Clinician: 0.65). The degree to which the DenseNet model outperformed each clinician ranged and was clinician specific (AUC improvement 0.01¿0.14). Conclusion: Comprehensive review of CTP improves diagnostic performance and agreement amongst clinicians. A DenseNet model was superior to best mean clinician performance. The degree of improvement varied by specific clinician. Development of a clinician-DenseNet approach may improve inter-clinician agreement and diagnostic accuracy. This approach may alleviate limited specialist services in resource constrained settings.

Objectives: This study sought to establish the cost-effectiveness of endovascular thrombectomy (EVT) in M2 occlusions compared with patients who did not have EVT using both real-world and clinical trial evidence. Methods: The effectiveness of EVT in M2 occlusions was informed by the International Stroke Perfusion Imaging Registry (INSPIRE, real-world data for a wide range of strokes) and HERMES collaboration, trial data. Patients who received EVT and non-EVT treatment from INSPIRE were matched according to baseline characteristics. A Markov model with 7 health states defined by the 3-month modified Rankin scale (mRS) was constructed. Endovascular thrombectomy and non-EVT-treated patients in real-world, and clinical trials were run through the Markov model separately to generate the results from a limited societal perspective. National statistics and published literature informed the long-term probability of recurrent stroke, mortality, costs of management post-stroke, non-medical care, and nursing home care. Results: A total of 83 (42 EVT and 41 non-EVT) patients were matched of 278 (45 EVT and 233 non-EVT) patients in INSPIRE who had M2 occlusion stroke at presentation. The long-term simulation estimated that offering EVT to M2 occlusion stroke patients was associated with greater benefits (5.48 EVT vs 5.24 non-EVT quality-adjusted life year [QALY]) and higher costs (A$133 457 EVT vs A$126 127 non-EVT) compared with non-EVT treatment in real-world from a limited societal perspective. The incremental cost-effectiveness ratio (ICER) of EVT in real-world was A$29 981 (¿19 488)/QALY. The analysis using the data from HERMES collaboration yielded consistent results for the EVT patients. Comparison with real-world cost-effectiveness analyses of EVT in internal carotid artery/middle cerebral artery-M1 (ICA/MCA-M1) occlusion suggested a potential reduced QALY gains and increased ICER in M2 occlusions. Conclusions: Our study suggested that the benefits gained from EVT in M2 occlusion stroke in the real-world were similar to that derived from the clinical trials. The clinical and cost benefits from EVT appeared to be reduced in M2 compared with that from the ICA/MCA-M1 occlusions. Clinical Impact: Our study has provided valuable insights into the clinical significance of endovascular therapy (EVT) in the context of M2 occlusion stroke within a real-world setting. It is noteworthy that our findings indicate that the benefits obtained from EVT in M2 occlusion stroke closely align with those observed in controlled clinical trials. However, it is essential to recognize that there is a reduction in the clinical and cost-related advantages when comparing M2 occlusions to more proximal ICA/MCA-M1 occlusions.

Background: No treatment is available to prevent brain oedema, which can occur after a large hemispheric infarction. Glibenclamide has previously been shown to improve functional outcome and reduce neurological or oedema-related death in patients younger than 70 years who were at risk of brain oedema after an acute ischaemic stroke. We aimed to assess whether intravenous glibenclamide could improve functional outcome at 90 days in patients with large hemispheric infarction. Methods: CHARM was a phase 3, double-blind, placebo-controlled, randomised trial conducted across 143 acute stroke centres in 21 countries. We included patients aged 18¿85 years with a large stroke, defined either by an Alberta Stroke Program Early CT Score (ASPECTS) of 1¿5 or by an ischaemic core lesion volume of 80¿300 mL on CT perfusion or MRI diffusion-weighted imaging. Patients were randomly assigned in a 1:1 ratio to either intravenous glibenclamide (8·6 mg over 72 h) or placebo. The study drug was started within 10 h of stroke onset. The primary efficacy outcome was the shift in the distribution of scores on the modified Rankin Scale at day 90, as a measure of functional outcome. The primary efficacy outcome was analysed in a modified intention-to-treat population, which included all randomly assigned patients aged 18¿70 years. The safety population comprised all randomly assigned patients who received a dose. This trial is registered with ClinicalTrials.gov (NCT02864953). The trial was stopped early by the sponsor for strategic and operational reasons (slow enrolment because of COVID-19), before any unblinding or knowledge of the trial results. Findings: Between Aug 29, 2018, and May 23, 2023, 535 patients were enrolled and randomly assigned, of whom 518 received a dose (safety population) and 431 were aged 18¿70 years and comprised the modified intention-to-treat population (217 were assigned glibenclamide and 214 placebo). The mean age of patients was 58·7 (SD 9·0) years in the placebo group and 58·0 (9·5) years in the glibenclamide group; the median US National Institutes of Health Stroke Scale (NIHSS) score was 19 (IQR 16¿23) in the placebo group and 19 (IQR 16¿22) in the glibenclamide group; and the mean time from stroke onset to study drug start was 8·9 h (SD 2·1) in the placebo group and 9·2 h (2·1) in the glibenclamide group. Intravenous glibenclamide was not associated with a favourable shift in the modified Rankin scale at 90 days (common odds ratio [OR] 1·17 [95% CI 0·80¿1·71], p=0·42). 90-day mortality was 29% (61 of 214) in the placebo group and 32% (70 of 217) in the glibenclamide group (hazard ratio 1·20 [0·85¿1·70]; p=0·30). Serious adverse events in the prespecified safety population were consistent with the known safety profile of glibenclamide and included hypoglycaemia in 15 (6%) of 259 patients in the glibenclamide group and in four (2%) of 259 patients in the placebo group, leading to dose interruption or reduction in seven (3%) patients in the glibenclamide group and in one (<1%) in the placebo group. Interpretation: Intravenous glibenclamide did not improve functional outcome in patients aged 18¿70 years after large hemispheric infarction, although the trial was underpowered to make definitive conclusions because it was stopped early. Future prospective evaluation could be warranted to identify a possible benefit of intravenous glibenclamide in specific subgroups. Funding: Biogen.

Importance: One of 10 patients develop epilepsy in the late phase after cerebral venous thrombosis (CVT) diagnosis but predicting the individual risk is difficult. Objective: To develop and externally validate a prognostic score to estimate the individual risk of post-CVT epilepsy. Design, Setting, and Participants: This observational cohort study included both retrospective and prospective patients enrolled from 1994 through 2022. For development of the DIAS3 score, data from the International CVT Consortium (n = 1128), a large international hospital-based multicenter CVT cohort, were used. For validation, data from 2 independent multicenter cohorts, the ACTION-CVT (n = 543) and the Israel CVT study (n = 556), were used. Of 2937 eligible, consecutively enrolled adult patients with radiologically verified CVT, 710 patients with a history of epilepsy prior to CVT, follow-up less than 8 days, and missing late seizure status were excluded. Exposure: The prediction score (DIAS3) was developed based on available literature and clinical plausibility and consisted of 6 readily available clinical variables collected during the acute phase: decompressive hemicraniectomy, intracerebral hemorrhage at presentation, age, seizure(s) in the acute phase (excluding status epilepticus), status epilepticus in the acute phase, and subdural hematoma at presentation. Main Outcome and Measure: Time to a first late seizure, defined as occurring more than 7 days after diagnosis of CVT. Results: Of 1128 patients included in the derivation cohort (median age, 41 [IQR, 30-53] years; 805 women [71%]), 128 (11%) developed post-CVT epilepsy during a median follow-up of 12 (IQR, 3-26) months. According to the DIAS3 score, the predicted 1-year and 3-year risk of epilepsy in individual patients ranged from 7% to 68% and 10% to 83%, respectively. Internal and external validation showed adequate discrimination in the derivation cohort (1 year and 3 years: C statistic, 0.74; 95% CI, 0.70-0.79) and the 2 independent validation cohorts, (ACTION-CVT) 1 year: C statistic, 0.76; 95% CI, 0.67-0.84; 3 years: C statistic, 0.77; 95% CI, 0.66-0.84; and Israel CVT study 1 year: C statistic, 0.80; 95% CI, 0.75-0.86. Calibration plots indicated adequate agreement between predicted and observed risks. Conclusions and Relevance: The DIAS3 score (freely available online) is a simple tool that can help predict the risk of post-CVT epilepsy in individual patients. The model can improve opportunities for personalized medicine and may aid in decision-making regarding antiseizure medication, patient counseling, and facilitation of research on epileptogenesis in CVT.

(Figure presented.)

Background: Individuals with minor ischaemic stroke and intracranial occlusion are at increased risk of poor outcomes. Intravenous thrombolysis with tenecteplase might improve outcomes in this population. We aimed to test the superiority of intravenous tenecteplase over non-thrombolytic standard of care in patients with minor ischaemic stroke and intracranial occlusion or focal perfusion abnormality. Methods: In this multicentre, prospective, parallel group, open label with blinded outcome assessment, randomised controlled trial, adult patients (aged =18 years) were included at 48 hospitals in Australia, Austria, Brazil, Canada, Finland, Ireland, New Zealand, Singapore, Spain, and the UK. Eligible patients with minor acute ischaemic stroke (National Institutes of Health Stroke Scale score 0¿5) and intracranial occlusion or focal perfusion abnormality were enrolled within 12 h from stroke onset. Participants were randomly assigned (1:1), using a minimal sufficient balance algorithm to intravenous tenecteplase (0·25 mg/kg) or non-thrombolytic standard of care (control). Primary outcome was a return to baseline functioning on pre-morbid modified Rankin Scale score in the intention-to-treat (ITT) population (all patients randomly assigned to a treatment group and who did not withdraw consent to participate) assessed at 90 days. Safety outcomes were reported in the ITT population and included symptomatic intracranial haemorrhage and death. This trial is registered with ClinicalTrials.gov, NCT02398656, and is closed to accrual. Findings: The trial was stopped early for futility. Between April 27, 2015, and Jan 19, 2024, 886 patients were enrolled; 369 (42%) were female and 517 (58%) were male. 454 (51%) were assigned to control and 432 (49%) to intravenous tenecteplase. The primary outcome occurred in 338 (75%) of 452 patients in the control group and 309 (72%) of 432 in the tenecteplase group (risk ratio [RR] 0·96, 95% CI 0·88¿1·04, p=0·29). More patients died in the tenecteplase group (20 deaths [5%]) than in the control group (five deaths [1%]; adjusted hazard ratio 3·8; 95% CI 1·4¿10·2, p=0·0085). There were eight (2%) symptomatic intracranial haemorrhages in the tenecteplase group versus two (<1%) in the control group (RR 4·2; 95% CI 0·9¿19·7, p=0·059). Interpretation: There was no benefit and possible harm from treatment with intravenous tenecteplase. Patients with minor stroke and intracranial occlusion should not be routinely treated with intravenous thrombolysis. Funding: Heart and Stroke Foundation of Canada, Canadian Institutes of Health Research, and the British Heart Foundation.

Introduction: Evidence-based blood pressure (BP) targets in acute ischaemic stroke are lacking. Previous observational studies have focused on single baseline BP and clinical outcomes, without consideration for dynamic changes. We aim to determine the association between BP parameters including variability, peak, nadir, median and mean during stroke and infarct growth (primary outcome), risk of haemorrhagic transformation, and functional outcome (secondary outcomes). Methods: Suspected stroke patients were prospectively recruited from a single comprehensive stroke centre. Multimodal computed tomography imaging was used to define infarct core. BP was recorded as per national stroke guidelines during the initial 24 h. Infarct growth and evidence of parenchymal haemorrhage were determined by follow-upmagnetic resonance imaging at 24 h. Functional outcome at 3 months was assessed using the modified Rankin Scale. Subgroup analysis was performed according to stroke aetiology and treatment for the association between BP, infarct volume growth, and risk of haemorrhagic transformation. The association between BP parameters and outcomes were determined using regression modelling. Results: A total of 229 patients were included in this study. Themedian agewas 67.4, 64.4%weremale, and the baseline National Institutes of Health Stroke Scale was 8. BP variability (BPV) was independently associated with increased infarct growth (multivariate coefficient 1.60, 95%CI: 0.27-2.94, p = 0.19) and an increased odds of parenchymal haemorrhage (adjusted OR 1.21, 95% CI: 1.02-1.44, p = 0.028). The odds of a favourable outcome at 90 days were inversely associated with BPV on simple, but not adjusted logistic regression. On subgroup analysis, only in patients with large vessel occlusions, undergoing endovascular clot retrieval, was BPV associated with infarct growth (multivariate-adjusted coefficient 2.62, 95% CI: 0.53-4.70, p = 0.014) and an increased odds of haemorrhagic transformation (adjusted OR 1.26, 95% CI: 1.01-1.57, p = 0.045). Conclusion: An increase in BPV was associated with infarct expansion, increased risk of haemorrhagic transformation and was negatively associated with favourable functional outcomes at 3 months.

Background: Incorporating cardiac CT with hyperacute stroke imaging may increase the yield for cardioembolic sources. It is not clarified whether stroke severity influences on rates of intracardiac thrombus. We aimed to investigate a National Institutes of Health Stroke Scale (NIHSS) threshold below which acute cardiac CT was unnecessary. Methods: Consecutive patients with suspected stroke who underwent multimodal brain imaging and concurrent non-gated cardiac CT with delayed timing were prospectively recruited from 1st December 2020 to 30th November 2021. We performed receiver operating characteristics analysis of the NIHSS and intracardiac thrombus on hyperacute cardiac CT. Results: A total of 314 patients were assessed (median age 69 years, 61% male). Final diagnoses were ischemic stroke (n=205; 132 etiology-confirmed stroke, independent of cardiac CT and 73 cryptogenic), transient ischemic attack (TIA) (n=21) and stroke-mimic syndromes (n=88). The total yield of cardiac CT was 8 intracardiac thrombus and 1 dissection. Cardiac CT identified an intracardiac thrombus in 6 (4.5%) with etiology-confirmed stroke, 2 (2.7%) with cryptogenic stroke, and none in patients with TIA or stroke-mimic. All of those with intracardiac thrombus had NIHSS =4 and this was the threshold below which hyperacute cardiac CT was not justified (sensitivity 100%, specificity 38%, positive predictive value 4.0%, negative predictive value 100%). Conclusions: A cutoff NIHSS =4 may be useful to stratify patients for cardiac CT in the hyperacute stroke setting to optimize its diagnostic yield and reduce additional radiation exposure.

Background: Telestroke networks aim to address variability in both quality and access to stroke care in rural areas, by providing remote access to expert stroke neurologists. Implementation of telestroke requires adaptation of workflow processes and education. We previously developed virtual reality (VR) workflow training and documented acceptability, utility and feasibility. The effects on acute stroke treatment metrics have not been previously described. Aims: The overall aim was to improve hyperacute stroke metrics and shorten the time-to-reperfusion therapy administration in rural settings. Methods: This study applies a natural experiment approach, collecting stroke metric data during transition from a pre-existing pilot to a statewide telestroke service at five rural hospitals. Pre- and post-intervention data included baseline patient demographics and assessment, diagnosis, and treatment delivery metrics. The primary study outcome was door-to-decision time (thrombolysis and endovascular thrombectomy). Secondary outcomes included door-to-computerized tomography time, door-to-thrombolysis time and proportion of patients receiving thrombolysis or thrombectomy treatment. Usage data relating to the VR stroke workflow training of interprofessional healthcare professionals was automatically captured via Wi-Fi. Statistical comparisons of clinical metrics between the pre- and post-intervention time periods, defined as the timeframes before and after VR deployment, were performed. Results: A total of 2,683 patients were included (April 2013¿December 2022); 1910 pre- and 773 post-intervention. All acute stroke time metrics significantly improved post-intervention. The primary outcome, door-to-decision time, decreased from 80 min [56¿118] to 54 min [40¿76; P < 0.001]. Secondary outcomes also improved, including door-to-thrombolysis time (90 min [68¿114] vs. 68.5 min [54¿90]; P < 0.001) and proportion of patients thrombolysed (11 vs. 16%; P < 0.001). The proportion of patients transferred for thrombectomy was unchanged (6 vs. 7%; P = 0.69). Seventy VR sessions totaling 15 h 39 min of training time were logged. VR training usage varied across sites (3¿31 sessions per site). Conclusions: Delivery of a multi-factorial intervention including infrastructure, funding, education and training (with VR workflow training) as part of a state-wide telestroke rollout was associated with improved acute stroke treatment metrics. Additional work is required to identify the contribution of each intervention component on clinical outcomes and to increase training uptake and sustainment.

After stroke onset, ischemic brain tissue will progress to infarction unless blood flow is restored. Core growth rate measures the infarction speed from stroke onset. This multicenter cohort study aimed to explore whether core growth rate influences benefit from the reperfusion treatment of endovascular thrombectomy in large ischemic core stroke patients. It identified 134 patients with large core volume >70 mL assessed on brain perfusion image within 9 hours of stroke onset. Of 134 patients, 71 received endovascular thrombectomy and 63 did not receive the treatment. Overall, poor outcomes were frequent, with 3-month severed disability or death rate at 56% in treatment group and 68% in no treatment group (p = 0.156). Patients were then stratified by core growth rate. For patients with 'ultrafast core growth' of >70 mL/hour, rates of poor outcome were especially high in patients without endovascular thrombectomy (n = 13/14, 93%) and relatively lower in patients received the treatment (n = 12/20, 60%, p = 0.033). In contrast, for patients with core growth rate <70 mL/hour, there was not a large difference in poor outcomes between patients with and without the treatment (55% vs. 61%, p = 0.522). Therefore, patients with 'ultrafast core growth' might stand to benefit the most from endovascular treatment.

Objectives: Emergency Medicine (EM) provider experiences consulting telestroke (TS) are poorly studied. In this qualitative study, we aimed to determine how TS changes patient management and to measure TS effects on EM provider confidence with acute ischemic stroke (AIS) treatment. Materials and methods: We designed a survey for EM providers querying perceptions of TS value, confidence with treating AIS, and counterfactuals regarding what EM providers would have done without TS. Eligible EM providers participated in an audio-visual TS consult within a 6-state TS network between 11/2016¿11/2017. Results: We received 48 surveys (response rate 43%). The most common reason (71%) for using TS was tPA eligibility expert opinion. Most EM providers (94%) thought the patient/family were satisfied with TS and none felt their medical knowledge was doubted because of using TS. EM providers had high confidence in diagnosing AIS (95%) and tPA decision-making (86%), but not in determining thrombectomy eligibility (10%). Among EM providers who administered tPA, 85% said tPA would not have been given without TS consultation. TS consultation changed patient diagnosis in 60% of all patients and treatment plans in 56% of non-stroke patients. Most EM providers (86%) had increased confidence in their knowledge of future stroke patient management. Nearly all TS consults (93%) resulted in EM providers being more likely to use TS again. Conclusions: TS consult frequently results in both patient management change and increased EM knowledge of stroke management with increased likelihood of repeat usage. Discomfort in determining eligibility for thrombectomy points to educational opportunities.

Introduction: The management of epilepsy during pregnancy requires optimal seizure control, avoiding the potential teratogenic effects of antiepileptic drugs. Objectives: This study aims to describe the clinical characteristics and perinatal outcomes of pregnant patients with epilepsy; to analyse the factors associated with seizures during pregnancy; to describe the most commonly used antiepileptic drugs in these patients; and to analyse changes in treatment regimens in 2 periods, 2000-2010 and 2011-2018. Methods: We conducted a prospective observational study of patients with epilepsy who reported their pregnancy between 2000 and 2018. Patients were evaluated in the first and second trimesters of pregnancy, after delivery, and at one year. Data were collected on demographic variables, epilepsy, and perinatal and obstetric variables. Results: A total of 101 pregnancies were included. Patients' mean age was 32.6 years; 55.4% had focal epilepsy, 38.6% had generalised epilepsy, and 5.9% had undetermined epilepsy. We recorded 90 live births, 9 miscarriages, and 5 cases of congenital malformations, 4 of which were born to women who received valproate monotherapy. Forty patients (39.6%) presented seizures, with 16 (40%) presenting generalised tonic-clonic seizures. The variables associated with seizures during pregnancy were poor seizure control in the year prior to pregnancy (66.7% vs. 15.1%; P <.001), treatment with 2 or more antiepileptic drugs (30% vs. 14.8%; P <.001), and untreated epilepsy (25% vs. 0%; P <.001). The antiepileptic drugs most widely used in monotherapy were lamotrigine (n = 19; 27.1%), valproate (n = 17; 24.2%), and levetiracetam (n = 12; 17.1%). In the most recent period (2011-2018), we observed a greater proportion patients receiving monotherapy (81.5%, vs. 55.3%), as well as a decrease in the use of carbamazepine (2.3%, vs. 23.1%) and valproate (20.5%, vs. 30.8%); and a marked increase in the use of levetiracetam (27.3%, vs. 0%). Conclusions: The factors associated with the presence of seizures during pregnancy were previous poor seizure control, treatment with 2 or more antiepileptic drugs, and lack of treatment during pregnancy. The most commonly used drugs were lamotrigine, valproate, and levetiracetam, with an increase in levetiracetam use and a decrease in valproate use being observed in the later period (2011-2018).

Importance: International guidelines recommend avoiding intravenous thrombolysis (IVT) in patients with ischemic stroke who have a recent intake of a direct oral anticoagulant (DOAC). Objective: To determine the risk of symptomatic intracranial hemorrhage (sICH) associated with use of IVT in patients with recent DOAC ingestion. Design, Setting, and Participants: This international, multicenter, retrospective cohort study included 64 primary and comprehensive stroke centers across Europe, Asia, Australia, and New Zealand. Consecutive adult patients with ischemic stroke who received IVT (both with and without thrombectomy) were included. Patients whose last known DOAC ingestion was more than 48 hours before stroke onset were excluded. A total of 832 patients with recent DOAC use were compared with 32375 controls without recent DOAC use. Data were collected from January 2008 to December 2021. Exposures: Prior DOAC therapy (confirmed last ingestion within 48 hours prior to IVT) compared with no prior oral anticoagulation. Main Outcomes and Measures: The main outcome was sICH within 36 hours after IVT, defined as worsening of at least 4 points on the National Institutes of Health Stroke Scale and attributed to radiologically evident intracranial hemorrhage. Outcomes were compared according to different selection strategies (DOAC-level measurements, DOAC reversal treatment, IVT with neither DOAC-level measurement nor idarucizumab). The association of sICH with DOAC plasma levels and very recent ingestions was explored in sensitivity analyses. Results: Of 33207 included patients, 14458 (43.5%) were female, and the median (IQR) age was 73 (62-80) years. The median (IQR) National Institutes of Health Stroke Scale score was 9 (5-16). Of the 832 patients taking DOAC, 252 (30.3%) received DOAC reversal before IVT (all idarucizumab), 225 (27.0%) had DOAC-level measurements, and 355 (42.7%) received IVT without measuring DOAC plasma levels or reversal treatment. The unadjusted rate of sICH was 2.5% (95% CI, 1.6-3.8) in patients taking DOACs compared with 4.1% (95% CI, 3.9-4.4) in control patients using no anticoagulants. Recent DOAC ingestion was associated with lower odds of sICH after IVT compared with no anticoagulation (adjusted odds ratio, 0.57; 95% CI, 0.36-0.92). This finding was consistent among the different selection strategies and in sensitivity analyses of patients with detectable plasma levels or very recent ingestion. Conclusions and Relevance: In this study, there was insufficient evidence of excess harm associated with off-label IVT in selected patients after ischemic stroke with recent DOAC ingestion..

Background: Failure to reperfuse a¿cerebral occlusion resulting in a¿persistent penumbral pattern has not been fully described. Methods: We retrospectively reviewed patients with anterior large vessel occlusion who did not receive reperfusion, and underwent repeated perfusion imaging, with baseline imaging <¿6¿h after onset and follow-up scans from 16¿168¿h. A¿persistent target mismatch (PTM) was defined as core volume of <¿100¿mL, mismatch ratio >¿1.2, and mismatch volume >¿10¿mL on follow-up imaging. Patients were divided into PTM or non-PTM groups. Ischemic core and penumbral volumes were compared between baseline and follow-up imaging between the two groups, and collateral flow status assessed using CT perfusion collateral index. Results: A total of 25 patients (14¿PTM and 11¿non-PTM) were enrolled in the study. Median core volumes increased slightly in the PTM group, from 22 to 36¿ml. There was a¿much greater increase in the non-PTM group, from 57 to 190¿ml. Penumbral volumes were stable in the PTM group from a¿median of 79¿ml at baseline to 88¿ml at follow-up, whereas penumbra was reduced in the non-PTM group, from 120 to 0¿ml. Collateral flow status was also better in the PTM group and the median collateral index was 33% compared with 44% in the non-PTM group (p¿= 0.043). Conclusion: Multiple patients were identified with limited core growth and large penumbra (persistent target mismatch) >¿16¿h after stroke onset, likely due to more favorable collateral flow.

Background: At least 20% of strokes involve the posterior circulation (PC). Compared to the anterior circulation, posterior circulation infarction (POCI) are frequently misdiagnosed. CT perfusion (CTP) has advanced stroke care by improving diagnostic accuracy and expanding eligibility for acute therapies. Clinical decisions are predicated upon precise estimates of the ischaemic penumbra and infarct core. Current thresholds for defining core and penumbra are based upon studies of anterior circulation stroke. We aimed to define the optimal CTP thresholds for core and penumbra in POCI. Methods: Data were analyzed from 331-patients diagnosed with acute POCI enrolled in the International-stroke-perfusion-registry (INSPIRE). Thirty-nine patients with baseline multimodal-CT with occlusion of a large PC-artery and follow up diffusion weighted MRI at 24¿48 h were included. Patients were divided into two-groups based on artery-recanalization on follow-up imaging. Patients with no or complete recanalisation were used for penumbral and infarct-core analysis, respectively. A Receiver operating curve (ROC) analysis was used for voxel-based analysis. Optimality was defined as the CTP parameter and threshold which maximized the area-under-the-curve. Linear regression was used for volume based analysis determining the CTP threshold which resulted in the smallest mean volume difference between the acute perfusion lesion and follow up MRI. Subanalysis of PC-regions was performed. Results: Mean transit time (MTT) and delay time (DT) were the best CTP parameters to characterize ischaemic penumbra (AUC = 0.73). Optimal thresholds for penumbra were a DT >1 s and MTT>145%. Delay time (DT) best estimated the infarct core (AUC = 0.74). The optimal core threshold was a DT >1.5 s. The voxel-based analyses indicated CTP was most accurate in the calcarine (Penumbra-AUC = 0.75, Core-AUC = 0.79) and cerebellar regions (Penumbra-AUC = 0.65, Core-AUC = 0.79). For the volume-based analyses, MTT >160% demonstrated best correlation and smallest mean-volume difference between the penumbral estimate and follow-up MRI (R2 = 0.71). MTT >170% resulted in the smallest mean-volume difference between the core estimate and follow-up MRI, but with poor correlation (R2 = 0.11). Conclusion: CTP has promising diagnostic utility in POCI. Accuracy of CTP varies by brain region. Optimal thresholds to define penumbra were DT >1 s and MTT >145%. The optimal threshold for core was a DT >1.5 s. However, CTP core volume estimates should be interpreted with caution.

Background: Adenovirus-based COVID-19 vaccines are extensively used in low- and middle-income countries (LMICs). Remarkably, cases of cerebral venous sinus thrombosis due to vaccine-induced immune thrombotic thrombocytopenia (CVST-VITT) have rarely been reported from LMICs. Aims: We studied the frequency, manifestations, treatment, and outcomes of CVST-VITT in LMICs. Methods: We report data from an international registry on CVST after COVID-19 vaccination. VITT was classified according to the Pavord criteria. We compared CVST-VITT cases from LMICs to cases from high-income countries (HICs). Results: Until August 2022, 228 CVST cases were reported, of which 63 were from LMICs (all middle-income countries [MICs]: Brazil, China, India, Iran, Mexico, Pakistan, Turkey). Of these 63, 32 (51%) met the VITT criteria, compared to 103 of 165 (62%) from HICs. Only 5 of the 32 (16%) CVST-VITT cases from MICs had definite VITT, mostly because anti-platelet factor 4 antibodies were often not tested. The median age was 26 (interquartile range [IQR] 20¿37) versus 47 (IQR 32¿58) years, and the proportion of women was 25 of 32 (78%) versus 77 of 103 (75%) in MICs versus HICs, respectively. Patients from MICs were diagnosed later than patients from HICs (1/32 [3%] vs. 65/103 [63%] diagnosed before May 2021). Clinical manifestations, including intracranial hemorrhage, were largely similar as was intravenous immunoglobulin use. In-hospital mortality was lower in MICs (7/31 [23%, 95% confidence interval (CI) 11¿40]) than in HICs (44/102 [43%, 95% CI 34¿53], p = 0.039). Conclusions: The number of CVST-VITT cases reported from LMICs was small despite the widespread use of adenoviral vaccines. Clinical manifestations and treatment of CVST-VITT cases were largely similar in MICs and HICs, while mortality was lower in patients from MICs.

Background and purpose: A prognostic score was developed to predict dependency and death after cerebral venous thrombosis (CVT) to identify patients for targeted therapy in future clinical trials. Methods: Data from the International CVT Consortium were used. Patients with pre-existent functional dependency were excluded. Logistic regression was used to predict poor outcome (modified Rankin Scale score 3¿6) at 6 months and Cox regression to predict 30-day and 1-year all-cause mortality. Potential predictors derived from previous studies were selected with backward stepwise selection. Coefficients were shrunk using ridge regression to adjust for optimism in internal validation. Results: Of 1454 patients with CVT, the cumulative number of deaths was 44 (3%) and 70 (5%) for 30 days and 1 year, respectively. Of 1126 patients evaluated regarding functional outcome, 137 (12%) were dependent or dead at 6 months. From the retained predictors for both models, the SI2NCAL2C score was derived utilizing the following components: absence of female-sex-specific risk factor, intracerebral hemorrhage, infection of the central nervous system, neurological focal deficits, coma, age, lower level of hemoglobin (g/l), higher level of glucose (mmol/l) at admission, and cancer. C-statistics were 0.80 (95% confidence interval [CI] 0.75¿0.84), 0.84 (95% CI 0.80¿0.88) and 0.84 (95% CI 0.80¿0.88) for the poor outcome, 30-day and 1-year mortality model, respectively. Calibration plots indicated a good model fit between predicted and observed values. The SI2NCAL2C score calculator is freely available at www.cerebralvenousthrombosis.com. Conclusions: The SI2NCAL2C score shows adequate performance for estimating individual risk of mortality and dependency after CVT but external validation of the score is warranted.

Introduction: Cerebral venous sinus thrombosis associated with vaccine-induced immune thrombotic thrombocytopenia (CVST-VITT) is a severe disease with high mortality. There are few data on sex differences in CVST-VITT. The aim of our study was to investigate the differences in presentation, treatment, clinical course, complications, and outcome of CVST-VITT between women and men. Patients and methods: We used data from an ongoing international registry on CVST-VITT. VITT was diagnosed according to the Pavord criteria. We compared the characteristics of CVST-VITT in women and men. Results: Of 133 patients with possible, probable, or definite CVST-VITT, 102 (77%) were women. Women were slightly younger [median age 42 (IQR 28¿54) vs 45 (28¿56)], presented more often with coma (26% vs 10%) and had a lower platelet count at presentation [median (IQR) 50x109/L (28¿79) vs 68 (30¿125)] than men. The nadir platelet count was lower in women [median (IQR) 34 (19¿62) vs 53 (20¿92)]. More women received endovascular treatment than men (15% vs 6%). Rates of treatment with intravenous immunoglobulins were similar (63% vs 66%), as were new venous thromboembolic events (14% vs 14%) and major bleeding complications (30% vs 20%). Rates of good functional outcome (modified Rankin Scale 0-2, 42% vs 45%) and in-hospital death (39% vs 41%) did not differ. Discussion and conclusions: Three quarters of CVST-VITT patients in this study were women. Women were more severely affected at presentation, but clinical course and outcome did not differ between women and men. VITT-specific treatments were overall similar, but more women received endovascular treatment.

Background and Purpose: The National Institutes of Health Stroke Scale (NIHSS) underestimates clinical severity in posterior circulation stroke and patients presenting with low NIHSS may be considered ineligible for reperfusion therapies. This study aimed to develop a modified version of the NIHSS, the Posterior NIHSS (POST-NIHSS), to improve NIHSS prognostic accuracy for posterior circulation stroke patients with mild-moderate symptoms. Methods: Clinical data of consecutive posterior circulation stroke patients with mild-moderate symptoms (NIHSS <10), who were conservatively managed, were retrospectively analyzed from the Basilar Artery Treatment and Management registry. Clinical features were assessed within 24 hours of symptom onset; dysphagia was assessed by a speech therapist within 48 hours of symptom onset. Random forest classification algorithm and constrained optimization were used to develop the POST-NIHSS in the derivation cohort. The POST-NIHSS was then validated in a prospective cohort. Poor outcome was defined as modified Rankin Scale score =3 at 3 months. Results: We included 202 patients (mean [SD] age 63 [14] years, median NIHSS 3 [interquartile range, 1-5]) in the derivation cohort and 65 patients (mean [SD] age 63 [16] years, median NIHSS 2 [interquartile range, 1-4]) in the validation cohort. In the derivation cohort, age, NIHSS, abnormal cough, dysphagia and gait/truncal ataxia were ranked as the most important predictors of functional outcome. POST-NIHSS was calculated by adding 5 points for abnormal cough, 4 points for dysphagia, and 3 points for gait/truncal ataxia to the baseline NIHSS. In receiver operating characteristic analysis adjusted for age, POST-NIHSS area under receiver operating characteristic curve was 0.80 (95% CI, 0.73-0.87) versus NIHSS area under receiver operating characteristic curve, 0.73 (95% CI, 0.64-0.83), P=0.03. In the validation cohort, POST-NIHSS area under receiver operating characteristic curve was 0.82 (95% CI, 0.69-0.94) versus NIHSS area under receiver operating characteristic curve 0.73 (95% CI, 0.58-0.87), P=0.04. Conclusions: POST-NIHSS showed higher prognostic accuracy than NIHSS and may be useful to identify posterior circulation stroke patients with NIHSS <10 at higher risk of poor outcome.

Objectives: There are several reports of the association between SARS-CoV-2 infection (COVID-19) and cerebral venous sinus thrombosis (CVST). In this study, we aimed to compare the hospitalization rate of CVST before and during the COVID-19 pandemic (before vaccination program). Materials and methods: In this retrospective cohort study, the hospitalization rate of adult CVST patients in Namazi hospital, a tertiary referral center in the south of Iran, was compared in two periods of time. We defined March 2018 to March 2019 as the pre-COVID-19 period and March 2020 to March 2021 as the COVID-19 period. Results: 50 and 77 adult CVST patients were hospitalized in the pre-COVID-19 and COVID-19 periods, respectively. The crude CVST hospitalization rate increased from 14.33 in the pre-COVID-19 period to 21.7 per million in the COVID-19 era (P = 0.021). However, after age and sex adjustment, the incremental trend in hospitalization rate was not significant (95% CrI: -2.2, 5.14). Patients > 50-year-old were more often hospitalized in the COVID-19 period (P = 0.042). SARS-CoV-2 PCR test was done in 49.3% out of all COVID-19 period patients, which were positive in 6.5%. Modified Rankin Scale (mRS) score =3 at three-month follow-up was associated with age (P = 0.015) and malignancy (P = 0.014) in pre-COVID period; and was associated with age (P = 0.025), altered mental status on admission time (P<0.001), malignancy (P = 0.041) and COVID-19 infection (P = 0.008) in COVID-19 period. Conclusion: Since there was a more dismal outcome in COVID-19 associated CVST, a high index of suspicion for CVST among COVID-19 positive is recommended.

Background: The benefit of combined treatment with intravenous thrombolysis before endovascular thrombectomy in patients with acute ischaemic stroke caused by large vessel occlusion remains unclear. We hypothesised that the clinical outcomes of patients with stroke with large vessel occlusion treated with direct endovascular thrombectomy within 4·5 h would be non-inferior compared with the outcomes of those treated with standard bridging therapy (intravenous thrombolysis before endovascular thrombectomy). Methods: DIRECT-SAFE was an international, multicentre, prospective, randomised, open-label, blinded-endpoint trial. Adult patients with stroke and large vessel occlusion in the intracranial internal carotid artery, middle cerebral artery (M1 or M2), or basilar artery, confirmed by non-contrast CT and vascular imaging, and who presented within 4·5 h of stroke onset were recruited from 25 acute-care hospitals in Australia, New Zealand, China, and Vietnam. Eligible patients were randomly assigned (1:1) via a web-based, computer-generated randomisation procedure stratified by site of baseline arterial occlusion and by geographic region to direct endovascular thrombectomy or bridging therapy. Patients assigned to bridging therapy received intravenous thrombolytic (alteplase or tenecteplase) as per standard care at each site; endovascular thrombectomy was also per standard of care, using the Trevo device (Stryker Neurovascular, Fremont, CA, USA) as first-line intervention. Personnel assessing outcomes were masked to group allocation; patients and treating physicians were not. The primary efficacy endpoint was functional independence defined as modified Rankin Scale score 0¿2 or return to baseline at 90 days, with a non-inferiority margin of ¿0·1, analysed by intention to treat (including all randomly assigned and consenting patients) and per protocol. The intention-to-treat population was included in the safety analyses. The trial is registered with ClinicalTrials.gov, NCT03494920, and is closed to new participants. Findings: Between June 2, 2018, and July 8, 2021, 295 patients were randomly assigned to direct endovascular thrombectomy (n=148) or bridging therapy (n=147). Functional independence occurred in 80 (55%) of 146 patients in the direct thrombectomy group and 89 (61%) of 147 patients in the bridging therapy group (intention-to-treat risk difference ¿0·051, two-sided 95% CI ¿0·160 to 0·059; per-protocol risk difference ¿0·062, two-sided 95% CI ¿0·173 to 0·049). Safety outcomes were similar between groups, with symptomatic intracerebral haemorrhage occurring in two (1%) of 146 patients in the direct group and one (1%) of 147 patients in the bridging group (adjusted odds ratio 1·70, 95% CI 0·22¿13·04) and death in 22 (15%) of 146 patients in the direct group and 24 (16%) of 147 patients in the bridging group (adjusted odds ratio 0·92, 95% CI 0·46¿1·84). Interpretation: We did not show non-inferiority of direct endovascular thrombectomy compared with bridging therapy. The additional information from our study should inform guidelines to recommend bridging therapy as standard treatment. Funding: Australian National Health and Medical Research Council and Stryker USA.

Aims: Hunter-8 and ACT-FAST are two stroke scales used in Australia for the pre-hospital identification of large vessel occlusion (LVO) stroke, but they have not previously been compared. Moreover, their use in identifying distal arterial occlusions has not previously been assessed. We therefore aimed to describe the area under the receiver operating curve (AUC) of Hunter-8 versus ACT-FAST for the detection of LVO stroke. Methods: Both scales were performed on consecutive patients presenting with stroke-like symptoms within 24 hours of symptom onset presenting to the emergency department at a tertiary referral hospital between June 2018 and January 2019. The AUC of Hunter-8 and ACT-FAST was calculated for the detection of LVO using different definitions (classic LVO ¿ proximal segment of the middle cerebral artery (MCA-M1), terminal internal carotid artery (T-ICA) or tandem occlusions ¿ and extended LVO ¿ classic LVO plus proximal MCA-M2 and basilar occlusions). Results: Of 126 suspected stroke patients, there were 24 classic LVO and 34 extended LVO. For detection of classic LVO, Hunter-8 had an AUC of 0.79 and ACT-FAST had an AUC of 0.77. For extended LVO, the AUC was 0.71 and 0.70 respectively. The AUC for the subgroup of patients with MCA-M2 and basilar occlusions was 0.42 and 0.43 respectively. Conclusion: Both scales represent a significant opportunity to identify patients with proven potential benefit from thrombectomy (classic LVO), however M2 and basilar occlusions may be more challenging to identify with these scales.

Objective: Cerebral venous thrombosis (CVT) caused by vaccine-induced immune thrombotic thrombocytopenia (VITT) is a rare adverse effect of adenovirus-based severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) vaccines. In March 2021, after autoimmune pathogenesis of VITT was discovered, treatment recommendations were developed. These comprised immunomodulation, non-heparin anticoagulants, and avoidance of platelet transfusion. The aim of this study was to evaluate adherence to these recommendations and its association with mortality. Methods: We used data from an international prospective registry of patients with CVT after the adenovirus-based SARS-CoV-2 vaccination. We analyzed possible, probable, or definite VITT-CVT cases included until January 18, 2022. Immunomodulation entailed administration of intravenous immunoglobulins and/or plasmapheresis. Results: Ninety-nine patients with VITT-CVT from 71 hospitals in 17 countries were analyzed. Five of 38 (13%), 11 of 24 (46%), and 28 of 37 (76%) of the patients diagnosed in March, April, and from May onward, respectively, were treated in-line with VITT recommendations (p < 0.001). Overall, treatment according to recommendations had no statistically significant influence on mortality (14/44 [32%] vs 29/55 [52%], adjusted odds ratio [OR]¿=¿0.43, 95% confidence interval [CI]¿=¿0.16¿1.19). However, patients who received immunomodulation had lower mortality (19/65 [29%] vs 24/34 [70%], adjusted OR¿=¿0.19, 95% CI¿=¿0.06¿0.58). Treatment with non-heparin anticoagulants instead of heparins was not associated with lower mortality (17/51 [33%] vs 13/35 [37%], adjusted OR¿=¿0.70, 95% CI¿=¿0.24¿2.04). Mortality was also not significantly influenced by platelet transfusion (17/27 [63%] vs 26/72 [36%], adjusted OR¿=¿2.19, 95% CI¿=¿0.74¿6.54). Conclusions: In patients with VITT-CVT, adherence to VITT treatment recommendations improved over time. Immunomodulation seems crucial for reducing mortality of VITT-CVT. ANN NEUROL 2022;92:562¿573.

Background and purpose: To explore the prevalence, risk factors, time correlation, characteristics and clinical outcome of dural arteriovenous fistulas (dAVFs) in a cerebral venous thrombosis (CVT) population. Methods: We included patients from the International CVT Consortium registries. Diagnosis of dAVF was confirmed centrally. We assessed the prevalence and risk factors for dAVF among consecutive CVT patients and investigated its impact on clinical outcome using logistic regression analysis. We defined poor outcome as modified Rankin Scale score 3¿6 at last follow-up. Results: dAVF was confirmed in 29/1218 (2.4%) consecutive CVT patients. The median (interquartile range [IQR]) follow-up time was 8¿(5¿23) months. Patients with dAVF were older (median [IQR] 53¿[44¿61] vs. 41¿[29¿53] years; p¿<¿0.001), more frequently male (69% vs. 33%; p¿<¿0.001), more often had chronic clinical CVT onset (>30 days: 39% vs. 7%; p¿<¿0.001) and sigmoid sinus thrombosis (86% vs. 51%; p¿<¿0.001), and less frequently had parenchymal lesions (31% vs. 55%; p¿=¿0.013) at baseline imaging. Clinical outcome at last follow-up did not differ between patients with and without dAVF. Additionally, five patients were confirmed with dAVF from non-consecutive CVT cohorts. Among all patients with CVT and dAVF, 17/34 (50%) had multiple fistulas and 23/34 (68%) had cortical venous drainage. Of 34 patients with dAVF with 36 separate CVT events, 3/36 fistulas (8%) were diagnosed prior to, 20/36 (56%) simultaneously and 13/36 after (36%, median 115 [IQR 38¿337] days) diagnosis of CVT. Conclusions: Dural arteriovenous fistulas occur in at least 2% of CVT patients and are associated with chronic CVT onset, older age and male sex. Most CVT-related dAVFs are detected simultaneously or subsequently to diagnosis of CVT.

Whole blood viscosity (WBV) is the intrinsic resistance to flow developed due to the frictional force between adjacent layers of flowing blood. Elevated WBV is an independent risk factor for stroke. Poor microcirculation due to elevated WBV can prevent adequate perfusion of the brain and might act as an important secondary factor for hypoperfusion in acute ischaemic stroke. In the present study, we examined the association of WBV with basal cerebral perfusion assessed by CT perfusion in acute ischaemic stroke. Confirmed acute ischemic stroke patients (n = 82) presenting in hours were recruited from the single centre. Patients underwent baseline multimodal CT (non-contrast CT, CT angiography and CT perfusion). Where clinically warranted, patients also underwent follow-up DWI. WBV was measured in duplicate within 2¿h after sampling from 5-mL EDTA blood sample. WBV was significantly correlated with CT perfusion parameters such as perfusion lesion volume, ischemic core volume and mismatch ratio; DWI volume and baseline NIHSS. In a multivariate linear regression model, WBV significantly predicted acute perfusion lesion volume, core volume and mismatch ratio after adjusting for the effect of occlusion site and collateral status. Association of WBV with hypoperfusion (increased perfusion lesion volume, ischaemic core volume and mismatch ratio) suggest the role of erythrocyte rheology in cerebral haemodynamic of acute ischemic stroke. The present findings open new possibilities for therapeutic strategies targeting erythrocyte rheology to improve cerebral microcirculation in stroke.

Introduction: Continuous surveillance of stroke admissions has been conducted in the Hunter region, Australia, over the past two decades. We aimed to describe the trends in incidence rates of hospitalised stroke and case-fatality rates in this region, 2001-2019. Methods: From a hospital-based stroke registry, data for admitted adult stroke patients residing in the Hunter region were collected using ICD-10 codes for ischemic and haemorrhagic stroke. Negative binomial regression and logistic regression analysis were used to analyse trends for age-standardised and age-specific incidence rates of hospitalised stroke and 28-day case-fatality rates. Results: A total of 14,662 hospitalisations for stroke in 13,242 individuals were registered. The age-standardised incidence rate declined from 123 per 100,000 population in the 2001-2005 epoch to 96 in the 2016-2019 epoch (mean annual change -2.0%, incidence rate ratio (IRR) = 0.980 [95%CI: 0.976-0.984]). Age-specific analyses identified significant reduction in the group aged 75-84 (1039 per 100,000 population in 2001-2005 to 633 in 2016-2019, annual change -3.5%, IRR= 0.965 [95%CI: 0.960-0.970]). The 28-day case-fatality rates fluctuated over time (18.5% in 2001-2005, 20.8% in 2010-2015, and 17.8% in 2016-2019). Projected population aging suggests annual volume of patients with new stroke will increase by 77% by 2041 if incidence rates remain unchanged at the 2016-2019 level. Conclusion: Although age-standardised hospitalised stroke incidence rates have declined in the Hunter region, the health system will face an increase in stroke hospitalisations related to the aging population.

Importance: Thrombosis with thrombocytopenia syndrome (TTS) has been reported after vaccination with the SARS-CoV-2 vaccines ChAdOx1 nCov-19 (Oxford-AstraZeneca) and Ad26.COV2.S (Janssen/Johnson & Johnson). Objective: To describe the clinical characteristics and outcome of patients with cerebral venous sinus thrombosis (CVST) after SARS-CoV-2 vaccination with and without TTS. Design, Setting, and Participants: This cohort study used data from an international registry of consecutive patients with CVST within 28 days of SARS-CoV-2 vaccination included between March 29 and June 18, 2021, from 81 hospitals in 19 countries. For reference, data from patients with CVST between 2015 and 2018 were derived from an existing international registry. Clinical characteristics and mortality rate were described for adults with (1) CVST in the setting of SARS-CoV-2 vaccine-induced immune thrombotic thrombocytopenia, (2) CVST after SARS-CoV-2 vaccination not fulling criteria for TTS, and (3) CVST unrelated to SARS-CoV-2 vaccination. Exposures: Patients were classified as having TTS if they had new-onset thrombocytopenia without recent exposure to heparin, in accordance with the Brighton Collaboration interim criteria. Main Outcomes and Measures: Clinical characteristics and mortality rate. Results: Of 116 patients with postvaccination CVST, 78 (67.2%) had TTS, of whom 76 had been vaccinated with ChAdOx1 nCov-19; 38 (32.8%) had no indication of TTS. The control group included 207 patients with CVST before the COVID-19 pandemic. A total of 63 of 78 (81%), 30 of 38 (79%), and 145 of 207 (70.0%) patients, respectively, were female, and the mean (SD) age was 45 (14), 55 (20), and 42 (16) years, respectively. Concomitant thromboembolism occurred in 25 of 70 patients (36%) in the TTS group, 2 of 35 (6%) in the no TTS group, and 10 of 206 (4.9%) in the control group, and in-hospital mortality rates were 47% (36 of 76; 95% CI, 37-58), 5% (2 of 37; 95% CI, 1-18), and 3.9% (8 of 207; 95% CI, 2.0-7.4), respectively. The mortality rate was 61% (14 of 23) among patients in the TTS group diagnosed before the condition garnered attention in the scientific community and 42% (22 of 53) among patients diagnosed later. Conclusions and Relevance: In this cohort study of patients with CVST, a distinct clinical profile and high mortality rate was observed in patients meeting criteria for TTS after SARS-CoV-2 vaccination..

This review paper summarises the yield of the different imaging modalities in the evaluation of patients for IV thrombolysis. Non-contrast CT and CTA or brain MRI combined with MRA are the recommended sequences for the evaluation of patients within the 4.5 hours time window. Multimodal MRI (DWI/PWI), and more recently, CT perfusion, offer reliable surrogate of salvageable penumbra, the target mismatch, which is now currently used as selection criteria for revascularisation treatment in an extended time window. Those sequences may also help the physician for the management of other limited cases when the diagnosis of acute ischemic stroke is difficult. Another approach the DWI/FLAIR mismatch has been proposed to identify among wake-up stroke patients those who have been experiencing an acute ischemic stroke evolving from less than 4.5 hrs. Other biomarkers, such as the clot imaging on MRI and CT, help to predict the recanalisation rate after IVT, while the impact of the presence microbleeds on MRI remains to be determined.

Background: Cerebral venous thrombosis (CVT) is associated with intracranial hemorrhage. Aim: To identify clinical and imaging features of CVT-associated intracranial hemorrhage. We hypothesized that higher clot burden would be associated with a higher risk of intracranial hemorrhage. Methods: We performed a retrospective analysis of an international, multicenter cohort of patients with confirmed cerebral venous thrombosis who underwent computed tomography within 2¿weeks of symptom onset. Clinical and imaging features were compared between patients with and without intracranial hemorrhage. Clot burden was assessed by counting the number of thrombosed venous sinuses and veins on confirmatory imaging. Results: We enrolled 260 patients from 10 institutions in Europe and Mexico. The mean age was 42¿years and 74% were female. Intracranial hemorrhage was found in 102 (39%). Among them parenchymal hemorrhage occurred in 64 (63%), in addition, small juxta-cortical hemorrhage was found in 30 (29%), subarachnoid hemorrhage in 24 (24%) and subdural hemorrhage in 11 (11%). Multiple concomitant types of hemorrhage occurred in 23 (23%). Older age and superior sagittal thrombosis involvement were associated with presence of hemorrhage. The number of thrombosed venous sinuses was not associated with intracranial hemorrhage (median number IQRInterquartile ratio] of sinuses/veins involved with hemorrhage 2 (1¿3) vs. 2 (1¿3) without hemorrhage, p = 0.4). Conclusion: The high rate of intracranial hemorrhage in cerebral venous thrombosis is not explained by widespread involvement of the venous sinuses. Superior sagittal sinus involvement is associated with higher bleeding risk.

Background: Patients who have had a stroke with unknown time of onset have been previously excluded from thrombolysis. We aimed to establish whether intravenous alteplase is safe and effective in such patients when salvageable tissue has been identified with imaging biomarkers. Methods: We did a systematic review and meta-analysis of individual patient data for trials published before Sept 21, 2020. Randomised trials of intravenous alteplase versus standard of care or placebo in adults with stroke with unknown time of onset with perfusion-diffusion MRI, perfusion CT, or MRI with diffusion weighted imaging-fluid attenuated inversion recovery (DWI-FLAIR) mismatch were eligible. The primary outcome was favourable functional outcome (score of 0¿1 on the modified Rankin Scale [mRS]) at 90 days indicating no disability using an unconditional mixed-effect logistic-regression model fitted to estimate the treatment effect. Secondary outcomes were mRS shift towards a better functional outcome and independent outcome (mRS 0¿2) at 90 days. Safety outcomes included death, severe disability or death (mRS score 4¿6), and symptomatic intracranial haemorrhage. This study is registered with PROSPERO, CRD42020166903. Findings: Of 249 identified abstracts, four trials met our eligibility criteria for inclusion: WAKE-UP, EXTEND, THAWS, and ECASS-4. The four trials provided individual patient data for 843 individuals, of whom 429 (51%) were assigned to alteplase and 414 (49%) to placebo or standard care. A favourable outcome occurred in 199 (47%) of 420 patients with alteplase and in 160 (39%) of 409 patients among controls (adjusted odds ratio [OR] 1·49 [95% CI 1·10¿2·03]; p=0·011), with low heterogeneity across studies (I2=27%). Alteplase was associated with a significant shift towards better functional outcome (adjusted common OR 1·38 [95% CI 1·05¿1·80]; p=0·019), and a higher odds of independent outcome (adjusted OR 1·50 [1·06¿2·12]; p=0·022). In the alteplase group, 90 (21%) patients were severely disabled or died (mRS score 4¿6), compared with 102 (25%) patients in the control group (adjusted OR 0·76 [0·52¿1·11]; p=0·15). 27 (6%) patients died in the alteplase group and 14 (3%) patients died among controls (adjusted OR 2·06 [1·03¿4·09]; p=0·040). The prevalence of symptomatic intracranial haemorrhage was higher in the alteplase group than among controls (11 [3%] vs two [<1%], adjusted OR 5·58 [1·22¿25·50]; p=0·024). Interpretation: In patients who have had a stroke with unknown time of onset with a DWI-FLAIR or perfusion mismatch, intravenous alteplase resulted in better functional outcome at 90 days than placebo or standard care. A net benefit was observed for all functional outcomes despite an increased risk of symptomatic intracranial haemorrhage. Although there were more deaths with alteplase than placebo, there were fewer cases of severe disability or death. Funding: None.

Aims: Penumbral selection is best-evidence practice for thrombectomy in the 6-24¿hour window. Moreover, it helps to identify the best responders to thrombolysis. Multimodal computed tomography (mCT) at the primary centre¿including noncontrast CT, CT perfusion, and CT angiography¿may enhance reperfusion therapy decision-making. We developed a network with five spoke primary stroke sites and assessed safety, feasibility, and influence of mCT in rural hospitals on decision-making for thrombolysis. Methods: Consecutive patients assessed via telemedicine from April 2013 to June 2018. Clinical outcomes were measured, and decision-making compared using theoretical models for reperfusion therapy applied without mCT guidance. Symptomatic intracranial hemorrhage (sICH) was assessed according to Safe Implementation of Treatments in Stroke Thrombolysis Registry criteria. Results: A total of 334 patients were assessed, 240 received mCT, 58 were thrombolysed (24.2%). The mean age of thrombolysed patients was 70¿years, median baseline National Institutes of Health Stroke Scale was 10 (IQR 7-18) and 23 (39.7%) had a large vessel occlusion. 1.7% had sICH and 3.5% parenchymal hematoma. Three months poststroke, 55% were independent, compared with 70% in the non-thrombolysed group. Conclusion: Implementation of CTP in rural centers was feasible and led to high thrombolysis rates with low rates of sICH.

Background: Transient ischemic attacks are common and place patients at risk of subsequent stroke. The 2007 EXPRESS and SOS-TIA studies demonstrated the efficacy of rapid treatment initiation. We hypothesized that with these findings having informed subsequent transient ischemic attacks management protocols, transient ischemic attacks prognosis in contemporary (2008 and later) patient cohorts would be more favorable than in historical cohorts. Methods: A systematic review and meta-analysis of cohort studies and randomized control trial placebo-arms of transient ischemic attack (published 2008¿2015). The primary outcome was stroke. Secondary outcomes were mortality, transient ischemic attack, and myocardial infarction. Studies were excluded if the outcome of transient ischemic attack patients was not reported separately. The systematic review included all studies of transient ischemic attack. The meta-analysis excluded studies of restricted transient ischemic attack patient types (e.g. only patients with atrial fibrillation). The pooled cumulative risks of stroke recurrence were estimated from study-specific estimates at 2, 7, 30, and 90 days post-transient ischemic attack, using a multivariate Bayesian model. Results: We included 47 studies in the systematic review and 40 studies in the meta-analysis. In the systematic review (191,202 patients), stroke at 2 days was reported in 13/47 (27.7%) of studies, at 7 days in 20/47 (42.6%), at 30 days in 12/47 (25.5%), and at 90 days in 33/47 (70.2%). Studies included in the meta-analysis recruited 68,563 patients. The cumulative risk of stroke was 1.2% (95% credible interval (CI) 0.6¿2.2), 3.4% (95% CI 2.0¿5.5), 5.0% (95% CI 2.9¿8.9), and 7.4% (95% CI 4.3¿12.4) at 2, 7, 30, and 90 days post-transient ischemic attack, respectively. Conclusion: In contemporary settings, transient ischemic attack prognosis is more favorable than reported in historical cohorts where a meta-analysis suggests stroke risk of 3.1% at two days.

BACKGROUND The time to initiate intravenous thrombolysis for acute ischemic stroke is generally limited to within 4.5 hours after the onset of symptoms. Some trials have suggested that the treatment window may be extended in patients who are shown to have ischemic but not yet infarcted brain tissue on imaging. METHODS We conducted a multicenter, randomized, placebo-controlled trial involving patients with ischemic stroke who had hypoperfused but salvageable regions of brain detected on automated perfusion imaging. The patients were randomly assigned to receive intravenous alteplase or placebo between 4.5 and 9.0 hours after the onset of stroke or on awakening with stroke (if within 9 hours from the midpoint of sleep). The primary outcome was a score of 0 or 1 on the modified Rankin scale, on which scores range from 0 (no symptoms) to 6 (death), at 90 days. The risk ratio for the primary outcome was adjusted for age and clinical severity at baseline. RESULTS After 225 of the planned 310 patients had been enrolled, the trial was terminated because of a loss of equipoise after the publication of positive results from a previous trial. A total of 113 patients were randomly assigned to the alteplase group and 112 to the placebo group. The primary outcome occurred in 40 patients (35.4%) in the alteplase group and in 33 patients (29.5%) in the placebo group (adjusted risk ratio, 1.44; 95% confidence interval [CI], 1.01 to 2.06; P = 0.04). Symptomatic intracerebral hemorrhage occurred in 7 patients (6.2%) in the alteplase group and in 1 patient (0.9%) in the placebo group (adjusted risk ratio, 7.22; 95% CI, 0.97 to 53.5; P = 0.05). A secondary ordinal analysis of the distribution of scores on the modified Rankin scale did not show a significant between-group difference in functional improvement at 90 days. CONCLUSIONS Among the patients in this trial who had ischemic stroke and salvageable brain tissue, the use of alteplase between 4.5 and 9.0 hours after stroke onset or at the time the patient awoke with stroke symptoms resulted in a higher percentage of patients with no or minor neurologic deficits than the use of placebo. There were more cases of symptomatic cerebral hemorrhage in the alteplase group than in the placebo group..

ObjectiveTo assess the added diagnostic value of semiquantitative imaging markers on noncontrast CT scans in cerebral venous thrombosis (CVT).MethodsIn a retrospective, multicenter, blinded, case-control study of patients with recent onset (<2 weeks) CVT, 3 readers assessed (1) the accuracy of the visual impression of CVT based on a combination of direct and indirect signs, (2) the accuracy of attenuation values of the venous sinuses in Hounsfield units (with adjustment for hematocrit levels), and (3) the accuracy of attenuation ratios of affected vs unaffected sinuses in comparison with reference standard MRI or CT angiography. Controls were age-matched patients with (sub)acute neurologic presentations.ResultsWe enrolled 285 patients with CVT and 303 controls from 10 international centers. Sensitivity of visual impression of thrombosis ranged from 41% to 73% and specificity ranged from 97% to 100%. Attenuation measurement had an area under the curve (AUC) of 0.78 (95% confidence interval [CI] 0.74-0.81). After adjustment for hematocrit, the AUC remained 0.78 (95% CI 0.74-0.81). The analysis of attenuation ratios of affected vs unaffected sinuses had AUC of 0.83 (95% CI 0.8-0.86). Adding this imaging marker significantly improved discrimination, but sensitivity when tolerating a false-positive rate of 20% was not higher than 76% (95% CI 0.70-0.81).ConclusionSemiquantitative analysis of attenuation values for diagnosis of CVT increased sensitivity but still failed to identify 1 out of 4 CVT.Classification of evidenceThis study provides Class II evidence that visual analysis of plain CT with or without attenuation measurements has high specificity but only moderate sensitivity for CVT.

Background: Stroke thrombolysis with alteplase is currently recommended 0¿4·5 h after stroke onset. We aimed to determine whether perfusion imaging can identify patients with salvageable brain tissue with symptoms 4·5 h or more from stroke onset or with symptoms on waking who might benefit from thrombolysis. Methods: In this systematic review and meta-analysis of individual patient data, we searched PubMed for randomised trials published in English between Jan 1, 2006, and March 1, 2019. We also reviewed the reference list of a previous systematic review of thrombolysis and searched ClinicalTrials.gov for interventional studies of ischaemic stroke. Studies of alteplase versus placebo in patients (aged =18 years) with ischaemic stroke treated more than 4·5 h after onset, or with wake-up stroke, who were imaged with perfusion-diffusion MRI or CT perfusion were eligible for inclusion. The primary outcome was excellent functional outcome (modified Rankin Scale [mRS] score 0¿1) at 3 months, adjusted for baseline age and clinical severity. Safety outcomes were death and symptomatic intracerebral haemorrhage. We calculated odds ratios, adjusted for baseline age and National Institutes of Health Stroke Scale score, using mixed-effects logistic regression models. This study is registered with PROSPERO, number CRD42019128036. Findings: We identified three trials that met eligibility criteria: EXTEND, ECASS4-EXTEND, and EPITHET. Of the 414 patients included in the three trials, 213 (51%) were assigned to receive alteplase and 201 (49%) were assigned to receive placebo. Overall, 211 patients in the alteplase group and 199 patients in the placebo group had mRS assessment data at 3 months and thus were included in the analysis of the primary outcome. 76 (36%) of 211 patients in the alteplase group and 58 (29%) of 199 patients in the placebo group had achieved excellent functional outcome at 3 months (adjusted odds ratio [OR] 1·86, 95% CI 1·15¿2·99, p=0·011). Symptomatic intracerebral haemorrhage was more common in the alteplase group than the placebo group (ten [5%] of 213 patients vs one [<1%] of 201 patients in the placebo group; adjusted OR 9·7, 95% CI 1·23¿76·55, p=0·031). 29 (14%) of 213 patients in the alteplase group and 18 (9%) of 201 patients in the placebo group died (adjusted OR 1·55, 0·81¿2·96, p=0·66). Interpretation: Patients with ischaemic stroke 4·5¿9 h from stroke onset or wake-up stroke with salvageable brain tissue who were treated with alteplase achieved better functional outcomes than did patients given placebo. The rate of symptomatic intracerebral haemorrhage was higher with alteplase, but this increase did not negate the overall net benefit of thrombolysis. Funding: None.

Background and Purpose - Poststroke fatigue affects a large proportion of stroke survivors and is associated with a poor quality of life. In a recent trial, modafinil was shown to be an effective agent in reducing poststroke fatigue; however, not all patients reported a significant decrease in fatigue with therapy. We sought to investigate clinical and radiological predictors of fatigue reduction with modafinil therapy in a stroke survivor cohort. Methods - Twenty-six participants with severe fatigue (multidimensional fatigue inventory-20 =60) underwent magnetic resonance imaging at baseline and during the last week of a 6-week treatment period of 200 mg modafinil taken daily. Resting-state functional magnetic resonance imaging and high-resolution structural imaging data were obtained, and functional connectivity and regional brain volumes within the fronto-striato-thalamic network were obtained. Linear regression analysis was used to identify predictors of modafinil-induced fatigue reduction. Results - Multiple regression analysis showed that baseline multidimensional fatigue inventory-20 score (ß=0.576, P=0.006) and functional connectivity between the dorsolateral prefrontal cortex and the caudate nucleus (ß=-0.424, P=0.008) were significant predictors of modafinil-associated decreases in poststroke fatigue (adjusted r2=0.52, area under the receiver operator characteristic curve=0.939). Conclusions - Fronto-striato-thalamic functional connectivity predicted modafinil response for poststroke fatigue. Fatigue in other neurological disease has been attributed to altered function of the fronto-striato-thalamic network and may indicate that poststroke fatigue has a similar mechanism to other neurological injury related fatigue. Self-reported fatigue in patients with normal fronto-striato-thalamic functional connectivity may have a different mechanism and require alternate therapeutic approaches.

Background: Evidence regarding whether imaging can be used effectively to select patients for endovascular thrombectomy (EVT) is scarce. We aimed to investigate the association between baseline imaging features and safety and efficacy of EVT in acute ischaemic stroke caused by anterior large-vessel occlusion. Methods: In this meta-analysis of individual patient-level data, the HERMES collaboration identified in PubMed seven randomised trials in endovascular stroke that compared EVT with standard medical therapy, published between Jan 1, 2010, and Oct 31, 2017. Only trials that required vessel imaging to identify patients with proximal anterior circulation ischaemic stroke and that used predominantly stent retrievers or second-generation neurothrombectomy devices in the EVT group were included. Risk of bias was assessed with the Cochrane handbook methodology. Central investigators, masked to clinical information other than stroke side, categorised baseline imaging features of ischaemic change with the Alberta Stroke Program Early CT Score (ASPECTS) or according to involvement of more than 33% of middle cerebral artery territory, and by thrombus volume, hyperdensity, and collateral status. The primary endpoint was neurological functional disability scored on the modified Rankin Scale (mRS) score at 90 days after randomisation. Safety outcomes included symptomatic intracranial haemorrhage, parenchymal haematoma type 2 within 5 days of randomisation, and mortality within 90 days. For the primary analysis, we used mixed-methods ordinal logistic regression adjusted for age, sex, National Institutes of Health Stroke Scale score at admission, intravenous alteplase, and time from onset to randomisation, and we used interaction terms to test whether imaging categorisation at baseline modifies the association between treatment and outcome. This meta-analysis was prospectively designed by the HERMES executive committee but has not been registered. Findings: Among 1764 pooled patients, 871 were allocated to the EVT group and 893 to the control group. Risk of bias was low except in the THRACE study, which used unblinded assessment of outcomes 90 days after randomisation and MRI predominantly as the primary baseline imaging tool. The overall treatment effect favoured EVT (adjusted common odds ratio [cOR] for a shift towards better outcome on the mRS 2·00, 95% CI 1·69¿2·38; p<0·0001). EVT achieved better outcomes at 90 days than standard medical therapy alone across a broad range of baseline imaging categories. Mortality at 90 days (14·7% vs 17·3%, p=0·15), symptomatic intracranial haemorrhage (3·8% vs 3·5%, p=0·90), and parenchymal haematoma type 2 (5·6% vs 4·8%, p=0·52) did not differ between the EVT and control groups. No treatment effect modification by baseline imaging features was noted for mortality at 90 days and parenchymal haematoma type 2. Among patients with ASPECTS 0¿4, symptomatic intracranial haemorrhage was seen in ten (19%) of 52 patients in the EVT group versus three (5%) of 66 patients in the control group (adjusted cOR 3·94, 95% CI 0·94¿16·49; pinteraction=0·025), and among patients with more than 33% involvement of middle cerebral artery territory, symptomatic intracranial haemorrhage was observed in 15 (14%) of 108 patients in the EVT group versus four (4%) of 113 patients in the control group (4·17, 1·30¿13·44, pinteraction=0·012). Interpretation: EVT achieves better outcomes at 90 days than standard medical therapy across a broad range of baseline imaging categories, including infarcts affecting more than 33% of middle cerebral artery territory or ASPECTS less than 6, although in these patients the risk of symptomatic intracranial haemorrhage was higher in the EVT group than the control group. This analysis provides preliminary evidence for potential use of EVT in patients with large infarcts at baseline. Funding: Medtronic.

Background: Computed tomography perfusion is becoming widely accepted and used in acute stroke treatment. Computed tomography perfusion provides pathophysiological information needed in the acute decision making. Moreover, computed tomography perfusion shows excellent correlation with diffusion-weighted imaging and perfusion-weighted sequences to evaluate core and penumbra volumes. Multimodal computed tomography perfusion has practical advantages over magnetic resonance imaging, including availability, accessibility, and speed. Nevertheless, it bears some limitations, as the limited accuracy for small ischemic lesions or brainstem ischemia. Interpretation of the computed tomography perfusion maps can sometimes be difficult. The stroke neurologist faces complex or atypical cases of cerebral ischemia and stroke mimics, and needs to decide whether the "lesions" on computed tomography perfusion are real or artifact. Aims: The purpose of this review is, based on clinical cases from a comprehensive stroke center, to describe the added value that computed tomography perfusion can provide to the stroke physician in the acute phase before a treatment decision is made.

Telestroke services have been shown to increase stroke therapy access in rural areas. The implementation of advanced CT imaging for patient assessment may improve patient selection and detection of stroke mimics in conjunction with telestroke. We implemented a telestroke service supported by multimodal CT imaging in a rural hospital in Australia. Over 21¿months we conducted an evaluation of service activation, thrombolysis rates and use of multimodal imaging to assess the feasibility of the service. Rates of symptomatic intracranial haemorrhage and 90-day modified Rankin Score were used as safety outcomes. Fifty-eight patients were assessed using telestroke, of which 41 were regarded to be acute ischemic strokes and 17 to be stroke mimics on clinical grounds. Of the 41 acute stroke patients, 22 patients were deemed eligible for thrombolysis. Using multimodal CT imaging, 8 more patients were excluded from treatment because of lack of treatment target. Multimodal imaging failed to be obtained in one patient. For the 14 treated patients, median door-imaging time was 38¿min. Median door-treatment time was 91¿min. A 90-day mRS ¿2 was achieved in 40% of treated patients. We conclude that a telestroke service using advanced CT imaging for therapy decision assistance can be successfully implemented in regional Australia and can be used to guide acute stroke treatment decision-making and improve access to thrombolytic therapy. Efficiency and safety is comparable to established telestroke services.

Objective: To compare the accuracy of Alberta Stroke Program Early Computed Tomography Score (ASPECTS) and CT perfusion to detect established infarction in acute anterior circulation stroke. Methods: We performed an observational study in 59 acute anterior circulation ischemic stroke patients who underwent brain noncontrast CT, CT perfusion, and MRI within 100 minutes from CT imaging. ASPECTS scores were calculated by 4 blinded vascular neurologists. The accuracy of ASPECTS and CT perfusion core volume to detect an acute MRI diffusion lesion of =70 mL was evaluated using receiver operating characteristics analysis and optimum cutoff values were calculated using Youden J. Results: Median ASPECTS score was 8 (interquartile range [IQR] 5-9). Median CT perfusion core volume was 22 mL (IQR 10.4-71.9). Median MRI diffusion lesion volume was 24.5 mL (IQR 10-63.9). No significant difference was found between the accuracy of CT perfusion and ASPECTS (c statistic 0.95 vs 0.87, p value for difference = 0.17). The optimum ASPECTS cutoff score to detect a diffusion-weighted imaging lesion =70 mL was <7 (sensitivity 0.74, specificity 0.86, Youden J = 0.60) and the optimum CT perfusion core volume cutoff was =50 mL (sensitivity 0.86, specificity 0.97, Youden J = 0.84). The CT perfusion core lesion covered a median of 100% (IQR 86%-100%) of the acute MRI lesion volume (Pearson R = 0.88; R 2 = 0.77). Conclusions: We found no significant difference between the accuracy of CT perfusion and ASPECTS to predict hyperacute MRI lesion volume in ischemic stroke.

Background Patients with acute ischemic stroke and large vessel occlusion (LVO) may benefit from prehospital identification and transfer to a center offering endovascular therapy. Aims We aimed to assess the accuracy of an existing 8-item stroke scale (National Institutes of Health Stroke Scale-8 [NIHSS-8]) for identification of patients with acute stroke with LVO. Methods We retrospectively calculated NIHSS-8 scores in a population of consecutive patients with presumed acute stroke assessed by emergency medical services (EMS). LVO was identified on admission computed tomography angiography. Accuracy to identify LVO was calculated using receiver operating characteristics analysis. We used weighted Cohen's kappa statistics to assess inter-rater reliability for the NIHSS-8 score between the EMS and the hospital stroke team on a prospectively evaluated subgroup. Results Of the 551 included patients, 381 had a confirmed ischemic stroke and 136 patients had an LVO. NIHSS scores were significantly higher in patients with LVO (median 18; interquartile range 14-22). The NIHSS-8 score reliably predicted the presence of LVO (area under the receiver operating characteristic curve.82). The optimum NIHSS-8 cutoff of 8 or more had a sensitivity of.81, specificity of.75, and Youden index of.56 for prediction of LVO. The EMS and the stroke team reached substantial agreement (¿ =.69). Conclusions Accuracy of the NIHSS-8 to identify LVO in a population of patients with suspected acute stroke is comparable to existing prehospital stroke scales. The scale can be performed by EMS with reasonable reliability. Further validation in the field is needed to assess accuracy of the scale to identify patients with LVO eligible for endovascular treatment in a prehospital setting.