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Background: The use of thrombectomy in patients with acute stroke and a large infarct of unrestricted size has not been well studied., Methods: We assigned, in a 1:1 ratio, patients with proximal cerebral vessel occlusion in the anterior circulation and a large infarct (as defined by an Alberta Stroke Program Early Computed Tomographic Score of ≤5; values range from 0 to 10) detected on magnetic resonance imaging or computed tomography within 6.5 hours after symptom onset to undergo endovascular thrombectomy and receive medical care (thrombectomy group) or to receive medical care alone (control group). The primary outcome was the score on the modified Rankin scale at 90 days (scores range from 0 to 6, with higher scores indicating greater disability). The primary safety outcome was death from any cause at 90 days, and an ancillary safety outcome was symptomatic intracerebral hemorrhage., Results: A total of 333 patients were assigned to either the thrombectomy group (166 patients) or the control group (167 patients); 9 were excluded from the analysis because of consent withdrawal or legal reasons. The trial was stopped early because results of similar trials favored thrombectomy. Approximately 35% of the patients received thrombolysis therapy. The median modified Rankin scale score at 90 days was 4 in the thrombectomy group and 6 in the control group (generalized odds ratio, 1.63; 95% confidence interval [CI], 1.29 to 2.06; P<0.001). Death from any cause at 90 days occurred in 36.1% of the patients in the thrombectomy group and in 55.5% of those in the control group (adjusted relative risk, 0.65; 95% CI, 0.50 to 0.84), and the percentage of patients with symptomatic intracerebral hemorrhage was 9.6% and 5.7%, respectively (adjusted relative risk, 1.73; 95% CI, 0.78 to 4.68). Eleven procedure-related complications occurred in the thrombectomy group., Conclusions: In patients with acute stroke and a large infarct of unrestricted size, thrombectomy plus medical care resulted in better functional outcomes and lower mortality than medical care alone but led to a higher incidence of symptomatic intracerebral hemorrhage. (Funded by Montpellier University Hospital; LASTE ClinicalTrials.gov number, NCT03811769.)., (Copyright © 2024 Massachusetts Medical Society.)

Background: The clinical benefit of mechanical thrombectomy(MT) for stroke patients with tandem occlusion is similar to that of isolated intracranial occlusions. However, the management of cervical internal carotid artery(ICA) occlusion during the MT, particularly in the setting of carotid dissection, remains controversial. We aimed to investigate the clinical impact of cervical ICA patency at day 1 on 3-month functional outcome., Methods: We collected data from the Endovascular Treatment in Ischemic Stroke, a prospective national registry in 30 French centers performing MT between January 2015 and January 2022. Inclusion criteria were consecutive tandem occlusions related to cervical ICA dissection treated with MT. Tandem occlusions of other etiology, isolated cervical ICA occlusions without intracranial thrombus and patients without day-1 ICA imaging were excluded. Primary endpoint was the 3-month functional outcome. Secondary endpoints included intracranial hemorrhage(ICH), excellent outcome, mortality and early neurological improvement. A sensitivity analysis was performed in patients with intracranial favorable recanalization after MT., Results: During the study period, 137 patients were included of which 89(65%) presented ICA patency at day 1. The odds of favorable outcome did not significantly differ between patients with patent and occluded ICA at day 1(68.7 vs 59.1%;aOR=1.30;95%CI 0.56-3.00,p=0.54). Excellent outcome, early neurological improvement, mortality and ICH were also comparable between groups. Sensitivity analysis showed similar results., Conclusion: ICA patency at day 1 in patients with tandem occlusions related to dissection did not seem to influence functional outcome. Endovascular recanalization of the cervical ICA including stenting might not be systematically required in this setting., Competing Interests: Declaration of competing interest The authors have no disclosure related to the present publication., (Copyright © 2024 The Author(s). Published by Elsevier Masson SAS.. All rights reserved.)

Rationale: Mechanical thrombectomy (MT) has become the standard of care for patients with acute ischemic stroke secondary to large vessel occlusion (LVO) of the anterior circulation. Conversely, its benefit in patients with National Institutes of Health Stroke Scale (NIHSS) score ⩽ 5 is unproven., Aim: To demonstrate the superiority of immediate MT plus best medical treatment (BMT) compared to BMT (with secondary MT in case of deterioration) for increasing the rate of modified Rankin Scale (mRS) score ⩽ 1 at 90 days after minor stroke (NIHSS score ⩽ 5) and anterior circulation LVO., Sample Size Estimates: To detect an absolute increase of 10% (80% power) in the 90-day mRS score = 0-1 rate in the MT + BMT group, by assuming an mRS score = 0-1 rate of 60% in the BMT group and by considering two interim efficacy/futility analyses (after study completion by 274 and 548 patients), 824 patients must be included by 36 centers in France, Spain, and the USA., Methods and Design: MOSTE is an international, multicenter, prospectively randomized into two parallel (1:1) arms, open-label, with blinded endpoint trial. Eligibility criteria are diagnosis of acute ischemic stroke within 23 h of last-seen-well, NIHSS score ⩽ 5, and LVO in the anterior circulation (intracranial internal carotid artery, M1 or M1-M2 segment of the middle cerebral artery)., Study Outcomes: The primary endpoint is the rate of excellent outcome at day 90 (mRS score = 0-1). Secondary endpoints include the rates of 90-day mRS score = 0-2 and score = 0, NIHSS score change, secondary MT, revascularization and infarct volume growth at 24 h, and quality of life and cognitive function at day 90. Safety outcomes (90-day all-cause mortality, procedural complications, symptomatic intracerebral hemorrhage, and rapid NIHSS score worsening) are recorded., Discussion: The MOSTE trial will determine MT efficacy and safety in patients with minor stroke and LVO in the anterior circulation., Trial Registration: MOSTE Trial. NCT03796468., Competing Interests: Declaration of conflicting interestsThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: CA, JL, HH, JFA, SR, NN, ON, GT, FD, AD declare no conflict of interest.BL received a research grant from Microvention, Balt, Phenox.BG received consultation fees from MIVI, Medtronic, Microvention, and Penumbra.IS received consultation fees from Medtronic.CC received consultation fees as Consultant for Medtronic, Microvention, Stryker, MIVI, Cerenovus.GM received consultation fees from Microvention, Stryker, Balt; paid lectures from Medtronic, Johnson & Johnson, Phenox.TGJ is advisor and investor for Anaconda, Route92, Viz.AI, FreeOx, Kandu and Methinks. He received personal fees in his role on Cerenovus DSMB and steering committee and Contego Medical screening committee. He received grant support from Medtronic and Stryker Neurovascular.VC received educational grant, consultation fees, and research grant from Medtronic, Stryker, Microvention, Cerenovus, Balt; educational grant and consultation fees from Phenox.

Background: Intravenous thrombolysis (IVT) for patients treated with mechanical thrombectomy (MT) for proximal occlusions has recently been questioned through randomized trials. However, few patients with M2 occlusions were included. We investigated the influence of prior IVT for patients presenting M2 occlusions treated with MT in comparison with MT alone., Methods: We conducted a retrospective analysis of the Endovascular Treatment in Ischemic Stroke (ETIS) registry, a multicenter observational study. Data from consecutive patients treated with MT for M2 occlusions between January 2015 and January 2022 at 26 comprehensive stroke centers were analyzed. The primary endpoint was 90-day modified Rankin Scale score of 0-2. Outcomes were compared using propensity score approaches. We also performed sensitivity analysis in relevant subgroups of patients., Results: Among 1132 patients with M2 occlusions treated with MT, 570 received prior IVT. The two groups were comparable after propensity analysis. The rate of favorable functional outcome was significantly higher in the IVT+MT group compared with the MT alone group (59.8% vs 44.7%; adjusted OR 1.38, 95% CI 1.10 to 1.75, P=0.008). Hemorrhagic and procedural complications were similar in both groups. In sensitivity analysis excluding patients with anticoagulation treatment, favorable recanalization was more frequent in the IVT+MT group (OR 1.37, 95% CI 1.11 to 1.70, P=0.004)., Conclusions: In cases of M2 occlusions, prior IVT combined with MT resulted in better functional outcome than MT alone, without increasing the rate of hemorrhagic or procedural complications. These results suggest the benefit of IVT in patients undergoing MT for M2 occlusions., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Patients treated with acute carotid stenting (CAS) may have higher odds of a favorable outcome than those treated without CAS during thrombectomy in tandem occlusions. Antiplatelet therapy is associated with CAS to avoid stent thrombosis, which occurs in around 20% of patients and negatively impacts outcomes. In this study we compared two antiplatelet strategies in tandem occlusion strokes treated with CAS and intracranial thrombectomy in clinical practice., Methods: The Endovascular Treatment in Ischemic Stroke Registry is an ongoing prospective observational study involving 21 comprehensive stroke centers performing thrombectomy in France. We analyzed patients with atherosclerotic tandem occlusions treated with acute CAS and intracranial thrombectomy who received at least one antiplatelet agent. Aggressive antiplatelet therapy included oral or intravenous glycoprotein (GP) IIb/IIIa or P2Y12 inhibitors. The primary outcome was cervical carotid artery patency at day 1 imaging follow-up., Results: Among the 187 included patients, 124 (66.3%) received aspirin alone and 63 (33.7%) received aggressive antiplatelet therapy. There was no significant difference regarding safety outcomes, especially in symptomatic intracerebral hemorrhage, parenchymal hematoma, and procedural complications. There was a significantly higher rate of carotid stent patency at day 1 in the aggressive antiplatelet therapy group (81.7% vs 97.1%, aOR 17.49, 95% CI 1.10 to 277.2, p=0.042). Odds of favorable functional outcome (90-day modified Rankin Scale score 0-2) were similar between the groups (OR 3.04, 95% CI 0.64 to 14.25, p=0.158)., Conclusions: In tandem occlusions treated with CAS plus thrombectomy, an aggressive antiplatelet regimen was associated with an increased rate of carotid stent patency at day 1 without safety concerns. Randomized trials are warranted to confirm these findings., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Weather conditions have been shown to influence the occurrence of cardiovascular events. We tested the hypothesis that weather parameters may be associated with variations of case volume of endovascular treatment (EVT) for acute ischemic stroke., Methods: Individual data from the ETIS (Endovascular Treatment in Ischemic Stroke) French national registry were matched to local weather stations. Meteorological parameters (rainfall, humidity, atmospheric pressure, air temperature) were gathered from national online resources. Weather readings and EVT case volumes were annually standardized per weather station and EVT center, and their associations tested with non-parametric univariable and generalized linear statistical models., Results: Between 2015 and 2021, 9913 EVT procedures addressed by 135 primary stroke units were matched to weather conditions. The mean daily case volume per center was 0.41 [StDev 0.33], and there was a median of 0.84 procedures daily linked to a weather station [StDev 0.47]. We found lower atmospheric pressure (β estimate -0.04; 95%CI[-0.07;-0.03], p<0.001), higher humidity (β estimate 0.07; 95%CI [0.05;0.09], p<0.001) and lower temperatures (β estimate -0.08; 95%CI[-0.10;-0.06], p<0.001) to be associated with higher standardized EVT daily case volumes. These associations were stable when testing them across strata of binned EVT standardized case volumes., Conclusions: Our study suggests that lower ambient temperature, lower atmospheric pressure, and higher air humidity are associated with significantly more daily EVT cases in a European temperate country. These results may provide insight into both system of care optimization at times of climate change and intracranial LVO pathophysiology. REGISTRATION-URL: https://clinicaltrials.gov/ct2/show/NCT03776877., Competing Interests: Declaration of Competing Interest There are no conflict of interest., (Copyright © 2023. Published by Elsevier Masson SAS.)

Background: Acute intracranial large vessel occlusion (LVO) is an important cause of morbidity and mortality among children; however, unlike in adults, no clinical trial has investigated the benefit of mechanical thrombectomy (MT) in pediatric LVO. Thus, MT remains an off-label procedure for pediatric stroke., Purpose: To investigate the efficacy and safety of MT in pediatric LVO., Methods: A systematic literature search was conducted in Ovid MEDLINE, Ovid Embase, Scopus, Web of Science, and Cochrane Central Register of Clinical Trials databases. Studies reporting safety and efficacy outcomes for endovascular treatment of pediatric LVO were included. Data regarding recanalization, functional outcome, symptomatic intracranial hemorrhage (sICH), and mortality were extracted from the included studies. Functional outcome was assessed with the modified Rankin scale (mRS). A fixed or random-effects model was used to calculate pooled event rates and 95% confidence intervals (CI)., Results: In this study 11 studies comprising 215 patients were included. The successful recanalization rate was 90.3% (95% CI = 85.77-95.11%), and complete recanalization was achieved in 52.7% (95% CI = 45.09-61.62%) of the cases. The favorable (mRS = 0-2) and excellent (mRS = 0-1) outcome rates were 83.3% (95% CI = 73.54-94.50%) and 59.5% (95% CI = 44.24-80.06%), respectively. The overall sICH prevalence was 0.59% (95% CI = 0-3.30%) and mortality rate was 3.2% (95% CI = 0.55-7.38%)., Conclusion: In our meta-analysis, MT demonstrated a promising safety and efficacy profile for pediatric patients, with consistently high efficacy outcomes and low complication rates. Our results support the utilization of MT in pediatric LVOs; however, prospective studies are still needed to further establish the role of pediatric MT as a first-line treatment strategy., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany.)

Background: Diffusion-weighted imaging lesion reversal (DWIR) is frequently observed after mechanical thrombectomy for acute ischemic stroke, but little is known about age-related differences and impact on outcome. We aimed to compare, in patients <80 versus ≥80 years old, (1) the effect of successful recanalization on DWIR and (2) the impact of DWIR on functional outcome., Methods: We retrospectively analyzed data of patients treated for an anterior circulation acute ischemic stroke with large vessel occlusion in 2 French hospitals, who underwent baseline and 24-hour follow-up magnetic resonance imaging, with baseline DWI lesion volume ≥10 cc. The percentage of DWIR (DWIR%), was calculated as follows: DWIR%=(DWIR volume/baseline DWI volume)×100. Data on demographics, medical history, and baseline clinical and radiological characteristics were collected., Results: Among 433 included patients (median age, 68 years), median DWIR% after mechanical thrombectomy was 22% (6-35) in patients ≥80, and 19% (interquartile range, 10-34) in patients <80 ( P =0.948). In multivariable analyses, successful recanalization after mechanical thrombectomy was associated with higher median DWIR% in both ≥80 ( P =0.004) and <80 ( P =0.002) patients. In subgroup analyses performed on a minority of subjects, collateral vessels status score (n=87) and white matter hyperintensity volume (n=131) were not associated with DWIR% ( P >0.2). In multivariable analyses, DWIR% was associated with increased rates of favorable 3-month outcomes in both ≥80 ( P =0.003) and <80 ( P =0.013) patients; the effect of DWIR% on outcome was not influenced by the age group ( P interaction=0.185) Conclusions: DWIR might be an important and nonage-dependent effect of arterial recanalization, as it seems to beneficially impact 3-month outcomes of both younger and older subjects treated with mechanical thrombectomy for acute ischemic stroke and large vessel occlusion., Competing Interests: Disclosures Dr Benzakoun reports travel support from Guerbet LLC. Dr Bricout reports compensation from Stryker for consultant services and compensation from Qapel Medical for consultant services. Dr Turc reports compensation from Guerbet France for other services. The other authors report no conflicts.

Background: The number of mechanical thrombectomy (MT) passes is strongly associated with angiographic reperfusion as well as clinical outcomes in patients with anterior circulation ischemic stroke. However, these associations have not been analyzed in patients with basilar artery occlusion (BAO). We investigated the influence of the number of MT passes on the degree of reperfusion and clinical outcomes, and compared outcome after ≤3 passes versus >3 passes., Methods: We used data from the prospective multicentric Endovascular Treatment in Ischemic Stroke (ETIS) Registry at 18 sites in France. Patients with BAO treated with MT were included. The primary outcome was a favorable outcome, defined as a modified Rankin Scale score of 0-3 at 90 days. We fit mixed multiple regression models, with center as a random effect., Results: We included 275 patients. Successful recanalization (modified Thrombolysis In Cerebral Infarction (mTICI) 2b-3) was achieved in 88.4%, and 41.8% had a favorable outcome. The odds ratio for favorable outcome with each pass above 1 was 0.41 (95% CI 0.23 to 0.73) and for recanalization (mTICI 2b-3) it was 0.70 (95% CI 0.57 to 0.87). In patients with ≤3 passes, the rate of favorable outcome in recanalized versus non-recanalized patients was 50.5% versus 10.0% (p=0.001), while in those with >3 passes it was 16.7% versus 15.2% (p=0.901)., Conclusions: We found that BAO patients had a significant relationship between the number of MT passes and both recanalization and favorable functional outcome. We further found that the benefit of recanalization in BAO patients was significant only when recanalization was achieved within three passes, encouraging at least three passes before stopping the procedure., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Endovascular treatment (EVT) for basilar artery occlusions (BAO) is associated with a higher rate of futile recanalization compared with anterior circulation procedures. We aimed to identify the incidence and predictors of poor clinical outcome despite successful reperfusion in current clinical practice., Methods: We used data from the ETIS (Endovascular Treatment in Ischemic Stroke) registry, a prospective multicenter observational registry of stroke treated with EVT in France. Patients undergoing EVT for acute BAO from January 2014 to May 2019 successfully treated within 8 hours from onset were included. Predictors of 90-day poor outcome (modified Rankin Scale (mRS) 4-6) were researched within patients with successful (modified Thrombolysis In Cerebral Infarction (mTICI 2b-3)) and excellent (mTICI 2c-3) reperfusion., Results: Among 242 patients treated within 8 hours, successful reperfusion was achieved in 195 (80.5%) and excellent reperfusion in 120 (49.5%). Poor outcome was observed in 107 (54.8%) and 60 (50%) patients, respectively. In patients with successful early reperfusion, age, higher initial National Institutes of Health Stroke Scale (NIHSS) score, lower posterior circulation Alberta Stroke Programme Early CT Score (pc-ASPECTS), and absence of prior intravenous thrombolysis were independent predictors of poor outcome. The only treatment factor with an independent predictive value was first-pass mTICI 2b-3 reperfusion (adjusted OR 0.13, 95% CI 0.05 to 0.37, p<0.001). In patients with excellent early reperfusion, independent predictors were age, initial NIHSS score, first-pass mTICI 2c-3 reperfusion, and hemorrhagic transformation on post-interventional imaging., Conclusions: Early successful reperfusion with EVT occurred in 80.5% of patients, and the only treatment-related factor predictive of clinical outcome was first pass mTICI 2b-3 reperfusion. Further research is warranted to identify the optimal techniques and devices associated with first pass reperfusion in the posterior circulation., Competing Interests: Competing interests: FC: Consulting fees from Medtronic, Stryker, Balt. Payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Penumbra, Balt, Medtronic. Participation on a Data Safety Monitoring Board or Advisory Board – Clinsearch. J-CG: Consulting fees from Medtronic, Stryker, Balt. Support for attending meetings and/or travel from Balt. Participation on a Data Safety Monitoring Board or Advisory Board – Intradys. AR: Consulting fees from Balt. IS: Consulting fees from Sanofi Synthé-Labo, Servier, Boheringer Ingelheim, Astra-Zeneca, Novonordisk, Medtronic. Payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Sanofi Synthé-Labo, Medtronic, Boheringer Ingelheim, Astra-Zeneca, BMS-Pfizer. GM: Consulting fees from Stryker. Payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Medtronic, Microvention., (© Author(s) (or their employer(s)) 2023. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Early neurological deterioration (END) after endovascular treatment (EVT) in patients with anterior circulation acute ischemic stroke (AIS) is associated with poor outcome. END may remain unexplained by parenchymal hemorrhage (UnEND). We aim to analyze the risk factors of UnEND in the medical management (MM) and EVT arms of the HERMES study., Methods: We conducted a post-hoc analysis of anterior AIS patients who underwent EVT for proximal anterior occlusions. Risk factors of UnEND, defined as a worsening of ≥4 points between baseline National Institutes of Health Stroke Scale (NIHSS) and NIHSS at 24 hours without hemorrhage, were compared between both arms using mixed logistic regression models adjusted for baseline characteristics. An interaction analysis between the EVT and MM arms for risk factors of UnEND was conducted., Results: Among 1723 patients assessable for UnEND, 160 patients experienced an UnEND (9.3%), including 9.1% (78/854) in the EVT arm and 9.4% (82/869) in the MM arm. There was no significant difference in the incidence of UnEND between the two study arms. In the EVT population, independent risk factors of UnEND were lower baseline NIHSS, higher baseline glucose, and lower collateral grade. In the MM population, the only independent predictor of UnEND was higher baseline glucose. However, we did not demonstrate an interaction between EVT and MM for baseline factors as risk factors of UnEND. UnEND was, similarly in both treatment groups, a significant predictor of unfavorable outcome in both the EVT (p<0.001) and MM (p<0.001) arms., Conclusions: UnEND is not an uncommon event, with a similar rate which ever treatment arm is considered. In the clinical scenario of AIS due to large vessel occlusion, no patient-related factor seems to increase the risk for UnEND when treated by EVT compared with MM., Competing Interests: Competing interests: PW is member of the editorial board of the Journal of Neurointerventional Surgery., (© Author(s) (or their employer(s)) 2023. No commercial re-use. See rights and permissions. Published by BMJ.)

Purpose: To provide recommendations for the anaesthetic and peri-operative management for thrombectomy procedure in stroke patients DESIGN: A consensus committee of 15 experts issued from the French Society of Anaesthesia and Intensive Care Medicine (Société Française d'Anesthésie et Réanimation, SFAR), the Association of French-language Neuro-Anaesthetists (Association des Neuro-Anesthésistes Réanimateurs de Langue Francaise, ANARLF), the French Neuro-Vascular Society (Société Francaise de Neuro-Vasculaire, SFNV), the French Neuro-Radiology Society (Société Francaise de Neuro-Radiologie, SFNR) and the French Study Group on Haemostasis and Thrombosis (Groupe Français d'Études sur l'Hémostase et la Thrombose, GFHT) was convened, under the supervision of two expert coordinators from the SFAR and the ANARLF. A formal conflict-of-interest policy was developed at the outset of the process and enforced throughout. The entire guideline elaboration process was conducted independently of any industry funding. The authors were required to follow the principles of the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system to guide their assessment of quality of evidence., Methods: Four fields were defined prior to the literature search: (1) Peri-procedural management, (2) Prevention and management of secondary brain injuries, (3) Management of antiplatelet and anticoagulant treatments, (4) Post-procedural management and orientation of the patient. Questions were formulated using the PICO format (Population, Intervention, Comparison, and Outcomes) and updated as needed. Analysis of the literature was then conducted and the recommendations were formulated according to the GRADE methodology., Results: The SFAR/ANARLF/SFNV/SFNR/GFHT guideline panel drew up 18 recommendations regarding anaesthetic management of mechanical thrombectomy procedures. Due to a lack of data in the literature allowing to conclude with high certainty on relevant clinical outcomes, the experts decided to formulate these guidelines as "Professional Practice Recommendations" (PPR) rather than "Formalized Expert Recommendations". After two rounds of rating and several amendments, a strong agreement was reached on 100% of the recommendations. No recommendation could be formulated for two questions., Conclusions: Strong agreement among experts was reached to provide a sizable number of recommendations aimed at optimising anaesthetic management for thrombectomy in patients suffering from stroke., (Copyright © 2022 The Author(s). Published by Elsevier Masson SAS.. All rights reserved.)

Background and Purpose: FLAIR vascular hyperintensities are thought to represent leptomeningeal collaterals in acute ischemic stroke. However, whether all-FLAIR vascular hyperintensities or FLAIR vascular hyperintensities-DWI mismatch, ie, FLAIR vascular hyperintensities beyond the DWI lesion, best reflects collaterals remains debated. We aimed to compare the value of FLAIR vascular hyperintensities-DWI mismatch versus all-FLAIR vascular hyperintensities for collateral assessment using PWI-derived collateral flow maps as a reference., Materials and Methods: We retrospectively reviewed the registries of 6 large stroke centers and included all patients with acute stroke with anterior circulation large-vessel occlusion who underwent MR imaging with PWI before thrombectomy. Collateral status was graded from 1 to 4 on PWI-derived collateral flow maps and dichotomized into good (grades 3-4) and poor (grades 1-2). The extent of all-FLAIR vascular hyperintensities and FLAIR vascular hyperintensities-DWI mismatch was assessed on the 7 cortical ASPECTS regions, ranging from 0 (absence) to 7 (extensive), and associations with good collaterals were compared using receiver operating characteristic curves., Results: Of the 209 included patients, 133 (64%) and 76 (36%) had good and poor collaterals, respectively. All-FLAIR vascular hyperintensity extent was similar between collateral groups ( P = .76). Conversely, FLAIR vascular hyperintensities-DWI mismatch extent was significantly higher in patients with good compared with poor collaterals ( P  < .001). The area under the curve was 0.80 (95% CI, 0.74-0.87) for FLAIR vascular hyperintensities-DWI mismatch and 0.52 (95% CI, 0.44-0.60) for all-FLAIR vascular hyperintensities ( P  < .001 for the comparison), to predict good collaterals. Variables independently associated with good collaterals were smaller DWI lesion volume ( P  < .001) and larger FLAIR vascular hyperintensities-DWI mismatch ( P = .02)., Conclusions: In acute ischemic stroke with large-vessel occlusion, the extent of FLAIR vascular hyperintensities does not reliably reflect collateral status unless one accounts for DWI., (© 2023 by American Journal of Neuroradiology.)

Background: Recent studies in the general stroke population treated with endovascular treatment (EVT) reported that higher pre-treatment lesional volumes were independently associated with poor neurological outcome and functional dependence after stroke. However, it has been not evaluated in older patients., Aim: We test the association between the pre-treatment lesional volume on diffusion-weighted magnetic resonance imaging and relevant outcome measures in older adults with stroke treated with EVT., Methods: We included consecutive older adults with stroke (⩾80 years old) treated with EVT in two academic comprehensive stroke centers. The association between pre-treatment lesional volume and relevant outcome measures (poor outcome (modified Rankin scale 4-6), 3-month mortality and symptomatic intracerebral hemorrhage (sICH)) was evaluated using univariate and multivariable models., Results: Five hundred seventy-nine patients were included (mean age: 85.6 ± 4.1, median lesional volume was 10 ml; interquartile range: 3-30 ml). Pre-treatment lesional volume was associated with poor functional outcome (adjusted odds ratio (aOR): 1.87, 95% confidence interval (CI): 1.60-2.20, for +1 logarithmic increase of lesional volume), 3-month mortality (aOR: 1.50, CI: 1.28-1.76), and sICH (aOR: 1.67, CI: 1.27-2.20). A threshold lesional volume >35 ml predicted 90% of patients with poor functional outcome and a cut-off >51 ml predicted 90% of patients dead at 3 months., Conclusions: Pre-treatment lesional volume might contribute, in association with other relevant clinical features, to the selection of older stroke patients who will benefit from EVT.

Purpose: To determine whether reversal of DWI lesions (DWIr) on the DWI-ASPECTS (diffusion weighted imaging Alberta Stroke Program CT Score) template should serve as a predictor of 90-day clinical outcome in acute ischemic stroke (AIS) patients with pretreatment diffusion-weighted imaging (DWI)-ASPECTS 0-5 treated with thrombectomy, and to determine its predictors in current practice., Methods: We analyzed data of all consecutive patients included in the prospective multicenter national Endovascular Treatment in Ischemic Stroke Registry between 1 January 2015 and 31 December 2020 with a premorbid mRS ≤ 2, who presented with a pretreatment DWI-ASPECTS 0-5 score, underwent thrombectomy and had an available 24 h post-interventional MRI follow-up. Multivariable analyses were performed to evaluate the clinical impact of DWIr on early neurological improvement (ENI), 3‑month modified Rankin scale (mRS) score distribution (shift analysis) and to define independent predictors of DWIr., Results: Early neurological improvement was detected in 82/211 (41.7%) of patients while 3‑month functional independence was achieved by 75 (35.5%) patients. The DWI reversal (39/211, 18.9%) resulted an independent predictor of both ENI (aOR 3.6, 95% CI 1.2-7.7; p 0.018) and 3‑month clinical outcome (aOR for mRS shift: 2.2, 95% CI 1-4.6; p 0.030). Only successful recanalization (mTICI 2c-3) independently predicted DWIr in the studied population (aOR 3.3, 95% CI 1.3-7.9; p 0.009)., Conclusion: The DWI reversal occurs in a non-negligible proportion of DWI-ASPECTS 0-5 patients subjected to thrombectomy and significantly influences clinical outcome. The mTICI 2c-3 recanalization emerged as an independent DWIr predictor., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany.)

Background and Purpose: Despite continuous improvement and growing knowledge in the endovascular therapy of large vessel occlusion stroke (LVOS), mechanical thrombectomy (MT) still fails to obtain satisfying intracranial recanalization in 10% to 15% of cases. However, little is known regarding clinical and radiological outcomes among this singularly underexplored subpopulation undergoing failed MT. We aimed to investigate the outcome after failed MT and identify predictive factors of favorable outcome despite recanalization failure., Methods: We conducted a retrospective analysis of consecutive patients prospectively included in the ongoing observational multicenter Endovascular Treatment in Ischemic Stroke registry from January 2015 to September 2020. Patients presenting with anterior circulation LVOS treated with MT but experiencing failed intracranial recanalization defined as final modified Thrombolysis In Cerebral Infarction (mTICI) score of 0, 1 and 2a were included. Clinical and radiological outcomes were assessed along with the exploration of predictive factors of Day-90 favorable outcome., Results: The study population comprised 533 patients. Mean age was 68.8 ± 16 years, and median admission National Institutes of Health Stroke Scale (NIHSS) and Alberta Stroke Program Early Computed Tomography Score (ASPECTS) were 17 (IQR 12-21) and 7 (IQR 5-8), respectively. Favorable outcomes were observed in 85 patients (18.2%) and 186 died (39.0%). The rate of symptomatic intracranial hemorrhage was 14.1%. In multivariable analysis, younger age (odds ratio [OR] 0.96, 95% CI 0.94-0.98, p &lt; 0.001), a lower admission NIHSS (OR 0.87, 95% CI 0.83-0.91, p &lt; 0.001), a lower number of MT passes (OR 0.77, 95% CI 0.77-0.87, p &lt; 0.001), a lower delta ASPECTS between initial and Day-1 imaging (OR 0.83, 95% CI 0.71-0.98, p = 0.026) and stroke etiology [significant difference among etiological subtypes (p = 0.024) with a tendency toward more favorable outcomes for dissection (OR 2.01, 95% CI 0.71-5.67)] were significantly associated with a 90-day favorable outcome., Conclusions: In this large retrospective analysis of a multicenter registry, we quantified the poor outcome after MT failure. We also identified factors associated with favorable outcome despite recanalization failure that might influence therapeutic management., (© 2022 The Authors. European Journal of Neurology published by John Wiley & Sons Ltd on behalf of European Academy of Neurology.)

Importance: There is to date limited evidence that revascularization strategies are associated with improved functional outcome in children with acute ischemic stroke (AIS)., Objectives: To report clinical outcomes and provide estimates of revascularization strategy safety and efficacy profiles of intravenous thrombolysis (IVT) and/or endovascular treatment (EVT) in children with AIS., Design, Setting, and Participants: The KidClot multicenter nationwide cohort study retrospectively collected data of children (neonates excluded) with AIS and recanalization treatment between January 1, 2015, and May 31, 2018. Data analysis was performed from January 1, 2015, to May 31, 2019., Exposure: IVT and/or EVT., Main Outcomes and Measures: Primary outcome was day 90 favorable outcome (modified Rankin Scale [mRs] 0-2, with 0 indicating no symptoms and 6 indicating death). Secondary end points included 1-year favorable outcome (mRs, 0-2), mortality, and symptomatic intracerebral hemorrhage. Other measures included the Pediatric National Institutes of Health Stroke Scale (pedNIHSS), with pedNIHSS 0 indicating no symptoms, 1 to 4 corresponding to a minor stroke, 5 to 15 corresponding to a mild stroke, greater than 15 to 20: severe stroke, and the adult Alberta Stroke Program Early CT Score (ASPECTS), which provides segmental assessment of the vascular territory, with 1 point deducted from the initial score of 10 for every region involved (from 10 [no lesion] to 0 [maximum lesions])., Results: Overall, 68 children were included in 30 centers (IVT [n = 44]; EVT [n = 40]; 44 boys [64.7%]; median [IQR] age, 11 [4-16] years; anterior circulation involvement, 57 [83.8%]). Median (IQR) pedNIHSS score at admission was 13 (7-19), higher in the EVT group at 16 (IQR, 10-20) vs 9 (6-17) in the IVT only group (P < .01). Median time from stroke onset to imaging was higher in the EVT group at 3 hours and 7 minutes (IQR, 2 hours and 3 minutes to 6 hours and 24 minutes) vs 2 hours and 39 minutes (IQR, 1 hour and 51 minutes to 4 hours and 13 minutes) (P = .04). Median admission ASPECTS score was 8 (IQR, 6-9). The main stroke etiologies were cardioembolic (21 [30.9%]) and focal cerebral arteriopathy (17 [25.0%]). Median (IQR) time from stroke onset to IVT was 3 hours and 30 minutes (IQR, 2 hours and 33 minutes to 4 hours and 28 minutes). In the EVT group, the rate of postprocedure successful reperfusion (≥modified Treatment in Cerebral Infarction 2b) was 80.0% (32 of 40). Persistent proximal arterial stenosis was more frequent in focal cerebral arteriopathy (P < .01). Death occurred in 3 patients (4.4%). Median pedNIHSS reduction at 24 hours was 4 (IQR, 0-9) points. Intracerebral hemorrhage occurred in 4 patients and symptomatic intracerebral hemorrhage occurred in 1 patient, all in the EVT group. The median mRS was 2 (IQR, 0-3) at day 90 and 1 (IQR, 0-2) at 1 year, which was not significantly different between EVT and IVT only groups, although different in initial severity., Conclusions and Relevance: The findings of this cohort study suggest that use of EVT and/or IVT is safe in children with AIS.

Background and Purpose: To determine the influence of the cerebral small vessel disease (SVD) burden on collateral recruitment in patients treated with mechanical thrombectomy (MT) for anterior circulation acute ischemic stroke (AIS)., Methods: Patients with AIS due to large vessel occlusion (LVO) from the Thrombectomie des Artères Cérébrales (THRACE) trial and prospective cohorts from 2 academic comprehensive stroke centers treated with MT were pooled and retrospectively analyzed. Collaterals' adequacy was assessed using the American Society of Interventional and Therapeutic Radiology/Society of Interventional Radiology (ASITN/SIR) score on initial digital subtraction angiography and dichotomized as good (3,4) versus poor (0-2) collaterals. The SVD burden was rated with the global SVD score on MRI. Multivariable logistic regression analyses were used to determine relationships between SVD and ASITN/SIR scores., Results: A total of 312 participants were included (53.2% males, mean age 67.8 ± 14.9 years). Two hundred and seven patients had poor collaterals (66.4%), and 133 (42.6%) presented with any SVD signature. In multivariable analysis, patients demonstrated worse leptomeningeal collaterality with increasing SVD burden before and after adjustment for SVD risk factors (adjusted odds ratio [aOR] 0.69; 95%CI [0.52-0.89] and aOR 0.66; 95%CI [0.5-0.88], respectively). Using individual SVD markers, poor collaterals were significantly associated with the presence of lacunes (aOR 0.40, 95% CI [0.20-0.79])., Conclusion: Our study provides evidence that in patients with AIS due to LVO treated with MT, the burden of SVD assessed by pre-treatment MRI is associated with poorer recruitment of leptomeningeal collaterals., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany.)

Background: Despite constant improvements in recent years, sufficient reperfusion after mechanical thrombectomy (MT) is not reached in up to 15% of patients with large vessel occlusion stroke (LVOS). The outcome of patients with unsuccessful reperfusion after MT especially after intravenous thrombolysis (IVT) use is not known. We investigated the influence of initial IVT in this particular group of patients with failed intracranial recanalization., Methods: We conducted a retrospective analysis of the Endovascular Treatment in Ischemic Stroke (ETIS) registry from January 2015 to December 2019. Patients presenting with LVOS of the anterior circulation and final modified Thrombolysis in Cerebral Infarction score (mTICI) of 0, 1 or 2a were included. Posterior circulation, isolated cervical carotid occlusions and successful reperfusions (mTICI 2b, 2c or 3) were excluded. The primary endpoint was favorable outcome (modified Rankin Scale score of 0-2) after 3 months. Secondary endpoints were safety outcomes including mortality, any intracranial hemorrhage (ICH), parenchymal hematoma (PH) and symptomatic intracranial hemorrhage (sICH) rates., Results: Among 5076 patients with LVOS treated with MT, 524 patients with insufficient recanalization met inclusion criteria, of which 242 received IVT and 282 did not. Functional outcome was improved in the MT+IVT group compared with the MT alone group, although the difference did not reach statistical significance (23.0% vs 12.9%; adjusted OR=1.82; 95% CI 0.98 to 3.38; p=0.058). However, 3 month mRS shift analysis showed a significant benefit of IVT (adjusted OR=1.68; 95% CI 1.56 to 6.54). ICH and sICH rates were similar in both groups, although PH rate was higher in the MT+IVT group (adjusted OR=3.20; 95% CI 1.56 to 6.54)., Conclusions: Among patients with LVOS in the anterior circulation and unsuccessful MT, IVT was associated with improved functional outcome even after unsuccessful MT. Despite recent trials questioning the place of IVT in the LVOS reperfusion strategy, these findings emphasize a subgroup of patients still benefiting from IVT., Competing Interests: Competing interests: Outside this work: JL reports grants from Stryker, Penumbra and Microvention. MM reports personal fees from Acticor Biotech, Air liquide, Amgen and Boerhinger., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Studies have suggested that collateral status modifies the effect of successful reperfusion on functional outcome after endovascular therapy (EVT). We aimed to assess the association between collateral status and EVT outcomes and to investigate whether collateral status modified the effect of successful reperfusion on EVT outcomes., Methods: We used data from the ongoing, prospective, multicenter Endovascular Treatment in Ischemic Stroke (ETIS) Registry. Collaterals were graded according to the American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN/SIR) guidelines. Patients were divided into two groups based on angiographic collateral status: poor (grade 0-2) versus good (grade 3-4) collaterals., Results: Among 2020 patients included in the study, 959 (47%) had good collaterals. Good collaterals were associated with favorable outcome (90-day modified Rankin Scale (mRS) 0-2) (OR 1.5, 95% CI 1.19 to 1.88). Probability of good outcome decreased with increased time from onset to reperfusion in both good and poor collateral groups. Successful reperfusion was associated with higher odds of favorable outcome in good collaterals (OR 6.01, 95% CI 3.27 to 11.04) and poor collaterals (OR 5.65, 95% CI 3.32 to 9.63) with no significant interaction. Similarly, successful reperfusion was associated with higher odds of excellent outcome (90-day mRS 0-1) and lower odds of mortality in both groups with no significant interaction. The benefit of successful reperfusion decreased with time from onset in both groups, but the curve was steeper in the poor collateral group., Conclusions: Collateral status predicted functional outcome after EVT. However, collateral status on the pretreatment angiogram did not decrease the clinical benefit of successful reperfusion., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: The predictors of successful reperfusion and the effect of reperfusion after endovascular treatment (EVT) for M2 occlusions have not been well studied. We aimed to identify predictors of successful reperfusion and the effect of reperfusion on outcomes of EVT for M2 occlusions in current practice., Methods: Patients with acute ischemic stroke due to isolated M2 occlusions who were enrolled in the prospective multicenter Endovascular Treatment in Ischemic Stroke (ETIS) Registry in France between January 2015 and March 2020 were included. The primary outcome was a favorable outcome, defined as modified Rankin Scale (mRS) score of 0-2 at 90 days. Successful reperfusion was defined as an improvement of ≥1 points in the modified Thrombolysis In Cerebral Infarction score between the first and the last intracranial angiogram., Results: A total of 458 patients were included (median National Institutes of Health Stroke Scale (NIHSS) score 14; 61.4% received prior intravenous thrombolysis). Compared with the non-reperfused patients, reperfused patients had an increased rate of excellent outcome (OR 2.3, 95% CI 0.98 to 5.36; p=0.053), favorable outcome (OR 2.79, 95% CI 1.31 to 5.93; p=0.007), and reduced 90-day mortality (OR 0.39, 95% CI 0.19 to 0.79; p<0.01). Admission NIHSS score was the only predictor of successful reperfusion. First-line strategy was not a predictor of successful reperfusion or favorable outcome, but the use of a stent retriever, alone or with an aspiration catheter, was associated with higher rates of procedural complications and 90-day mortality., Conclusions: Successful reperfusion of M2 occlusions reduced disability and mortality. However, safety is a concern, especially if the procedure failed., Competing Interests: Competing interests: BL reports grants from Stryker, Penumbra, and Microvention., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: The best recanalization strategy for mechanical thrombectomy (MT) remains unknown as no randomized controlled trial has simultaneously evaluated first-line stent retriever (SR) versus contact aspiration (CA) versus the combined approach (SR+CA)., Objective: To compare the efficacy and safety profiles of SR, CA, and SR+CA in patients with acute ischemic stroke (AIS) treated by MT., Methods: We analyzed data of the Endovascular Treatment in Ischemic Stroke (ETIS) Registry, a prospective, multicenter, observational study of patients with AIS treated by MT. Patients with M1 and intracranial internal carotid artery (ICA) occlusions between January 2015 and March 2020 in 15 comprehensive stroke centers were included. We assessed the association of first-line strategy with favorable outcomes at 3 months (modified Rankin Scale score 0-2), successful recanalization rates (modified Thrombolysis In Cerebral Infarction (mTICI) 2b/3), and safety outcomes., Results: We included 2643 patients, 406 treated with SR, 1126 with CA, and 1111 with SR+CA. CA or SR+CA achieved more successful recanalization than SR for M1 occlusions (aOR=2.09, (95% CI 1.39 to 3.13) and aOR=1.69 (95% CI 1.12 to 2.53), respectively). For intracranial ICA, SR+CA achieved more recanalization than SR (aOR=2.52 (95% CI 1.32 to 4.81)), no differences were observed between CA and SR+CA. SR+CA was associated with lower odds of favorable outcomes compared with SR (aOR=0.63 (95% CI 0.44 to 0.90)) and CA (aOR=0.71 (95% CI 0.55 to 0.92)), higher odds of mortality at 3 months (aOR=1.56 (95% CI 1.22 to 2.0)) compared with CA, and higher odds of symptomatic intracranial hemorrhage (aOR=1.59 (95% CI 1.1 to 2.3)) compared with CA., Conclusions: Despite high recanalization rates, our results question the safety of the combined approach, which was associated with disability and mortality. Randomized controlled trials are needed to evaluate the efficacy and safety of these techniques., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Background In acute ischemic stroke (AIS), fluid-attenuated inversion recovery (FLAIR) is used for treatment decisions when onset time is unknown. Synthetic FLAIR could be generated with deep learning from information embedded in diffusion-weighted imaging (DWI) and could replace acquired FLAIR sequence (real FLAIR) and shorten MRI duration. Purpose To compare performance of synthetic and real FLAIR for DWI-FLAIR mismatch estimation and identification of patients presenting within 4.5 hours from symptom onset. Materials and Methods In this retrospective study, all pretreatment and early follow-up (<48 hours after symptom onset) MRI data sets including DWI ( b = 0-1000 sec/mm 2 ) and FLAIR sequences obtained in consecutive patients with AIS referred for reperfusion therapies between January 2002 and May 2019 were included. On the training set (80%), a generative adversarial network was trained to produce synthetic FLAIR with DWI as input. On the test set (20%), synthetic FLAIR was computed without real FLAIR knowledge. The DWI-FLAIR mismatch was evaluated on both FLAIR data sets by four independent readers. Interobserver reproducibility and DWI-FLAIR mismatch concordance between synthetic and real FLAIR were evaluated with κ statistics. Sensitivity and specificity for identification of AIS within 4.5 hours were compared in patients with known onset time by using McNemar test. Results The study included 1416 MRI scans (861 patients; median age, 71 years [interquartile range, 57-81 years]; 375 men), yielding 1134 and 282 scans for training and test sets, respectively. Regarding DWI-FLAIR mismatch, interobserver reproducibility was substantial for real and synthetic FLAIR (κ = 0.80 [95% CI: 0.74, 0.87] and 0.80 [95% CI: 0.74, 0.87], respectively). After consensus, concordance between real and synthetic FLAIR was almost perfect (κ = 0.88; 95% CI: 0.82, 0.93). Diagnostic value for identifying AIS within 4.5 hours did not differ between real and synthetic FLAIR (sensitivity: 107 of 131 [82%] vs 111 of 131 [85%], P = .2; specificity: 96 of 104 [92%] vs 96 of 104 [92%], respectively, P > .99). Conclusion Synthetic fluid-attenuated inversion recovery (FLAIR) had diagnostic performances similar to real FLAIR in depicting diffusion-weighted imaging-FLAIR mismatch and in helping to identify early acute ischemic stroke, and it may accelerate MRI protocols. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Carroll and Hurley in this issue.

Background and Purpose: We aimed to evaluate among trained interventional neuroradiologist, whether increasing individual experience was associated with an improvement in mechanical thrombectomy (MT) procedural performance metrics., Methods: Individual MT procedural data from 5 centers of the Endovascular Treatment in Ischemic Stroke registry and 2 additional high-volume stroke centers were pooled. Operator experience was defined for each operator as a continuous variable, cumulating the number of MT procedures performed since January 2015, as MT became standard of care or, if later than this date, since the operator started performing mechanical thrombectomies in autonomy. We tested the associations between operator's experience and procedural metrics., Results: A total of 4516 procedures were included, performed by 36 operators at 7 distinct centers, with a median of 97.5 endovascular treatment procedures per operator (interquartile range, 57-170.2) over the study period. Higher operator's experience, analyzed as a continuous variable, was associated with a significantly shorter procedural duration (β estimate, -3.98 [95% CI, -5.1 to -2.8]; P <0.001), along with local anesthesia and M1 occlusion location in multivariable models. Increasing experience was associated with better Thrombolysis in Cerebral Infarction scores (estimate, 1.02 [1-1.04]; P =0.013)., Conclusions: In trained interventional neuroradiologists, increasing experience in MT is associated with significantly shorter procedural duration and better reperfusion rates, with a theoretical ceiling effect observed after around 100 procedures. These results may inform future training and practice guidelines to set minimal experience standards before autonomization, and to set-up operators' recertification processes tailored to individual case volume and prior experience.

Despite early thrombectomy, a sizeable fraction of acute stroke patients with large vessel occlusion have poor outcome. The no-reflow phenomenon, i.e. impaired microvascular reperfusion despite complete recanalization, may contribute to such "futile recanalizations". Although well reported in animal models, no-reflow is still poorly characterized in man. From a large prospective thrombectomy database, we included all patients with intracranial proximal occlusion, complete recanalization (modified thrombolysis in cerebral infarction score 2c-3), and availability of both baseline and 24 h follow-up MRI including arterial spin labeling perfusion mapping. No-reflow was operationally defined as i) hypoperfusion ≥40% relative to contralateral homologous region, assessed with both visual (two independent investigators) and automatic image analysis, and ii) infarction on follow-up MRI. Thirty-three patients were eligible (median age: 70 years, NIHSS: 18, and stroke onset-to-recanalization delay: 208 min). The operational criteria were met in one patient only, consistently with the visual and automatic analyses. This patient recanalized 160 min after stroke onset and had excellent functional outcome. In our cohort of patients with complete and stable recanalization following thrombectomy for intracranial proximal occlusion, severe ipsilateral hypoperfusion on follow-up imaging associated with newly developed infarction was a rare occurrence. Thus, no-reflow may be infrequent in human stroke and may not substantially contribute to futile recanalizations.

Background and Purpose: The number of clot retrieval attempts required to achieve complete reperfusion by mechanical thrombectomy impacts functional outcome in acute ischaemic stroke (AIS). Complete reperfusion [expanded Treatment In Cerebral Infarction (eTICI) score = 3] at first pass (FP), is associated with the highest rates of favorable outcome compared to complete reperfusion by multiple passes. The aim of the present study was to investigate the relationship between FP complete reperfusion and infarct growth (IG)., Methods: Anterior AIS patients with baseline and 24-h diffusion-weighted magnetic resonance imaging were included from two prospective registries. IG was measured by voxel-based segmentation of initial and 24-h diffusion-weighted imaging lesions. IG and favorable 3-month modified Rankin Scale (mRS) score (≤ 2) were compared between patients in whom complete reperfusion (eTICI 3) was achieved with a single pass (FP group) and those for whom multiple passes were required (MP group), after matching for confounding factors. Mediation analysis was performed to examine the association between FP and 3-month mRS score, with IG as mediating variable., Results: A total of 200 patients were included, of whom 118 (28.9%) had FP complete reperfusion. In case-control analysis, the FP group had lower IG than the MP group [8.7 (5.4-12.9) ml vs. 15.2 (11-22.6) ml, respectively; P = 0.03). Favorable outcome was higher in the FP population compared to a matched MP population (70.9% vs. 53.2%, respectively; P = 0.04). FP compete reperfusion (eTICI 3) was independently associated with favorable outcome in multivariable regression analysis [odds ratio 1.86, 95% confidence interval (CI) 1.01-4.39; P = 0.04]. The effect of complete reperfusion at FP on functional outcome was explained by limited IG in mediation analysis [indirect effect: -0.32 (95% CI -0.47 to -0.09)]., Conclusion: Complete reperfusion at FP is independently associated with significant decrease in IG compared to complete reperfusion by multiple attempts, explaining better functional outcomes., (© 2020 European Acadamy of Neurology.)

No controlled pharmacological studies are available in the field of pediatric stroke, except for sickle cell disease. Therefore, while pharmacological and mechanical recanalization treatments have repeatedly shown clinical benefit in adults with arterial ischemic stroke, pediatric strokologists still cannot base their therapeutic management (including hyperacute strategies) on high-level evidence. Once again, pediatricians face the same dichotomic choice: adapting adult procedures now versus waiting-for a long time-for the corresponding pediatric trials. One way out is building a compromise based on observational studies with large, longitudinal, comprehensive, real-life, and multisource dataset. Two recent high-quality observational studies have delivered promising conclusions on recanalization treatments in pediatric arterial ischemic stroke. TIPSTER (Thrombolysis in Pediatric Stroke Extended Results) showed that the risk of severe intracranial hemorrhage after intravenous thrombolysis is low; the Save Childs Study reported encouraging data about pediatric thrombectomy. Beyond the conclusion of a satisfactory global safety profile, a thorough analysis of the methods, populations, results, and therapeutic complications of these studies helps us to refine indications/contraindications and highlights the safeguards we need to rely on when discussing thrombolysis and thrombectomy in children. In conclusion, pediatric strokologists should not refrain from using clot lysis/retrieval tools in selected children with arterial ischemic stroke. But the implementation of hyperacute care is only feasible if the right candidate is identified through the sharing of common adult/pediatric protocols and ward collaboration, formalized well before the child's arrival. These anticipated protocols should never undervalue contraindications from adult guidelines and must involve the necessary pediatric expertise when facing specific causes of stroke, such as focal cerebral arteriopathy of childhood.

During the coronavirus disease 2019 (COVID-19) pandemic, the World Health Organization recommended measures to mitigate the outbreak such as social distancing and confinement. Since these measures have been put in place, anecdotal reports describe a decrease in the number of endovascular therapy (EVT) treatments for acute ischemic stroke due to large vessel occlusion. The purpose of our study was to determine the effect on EVT for patients with acute ischemic stroke during the COVID-19 confinement. In this retrospective, observational study, data were collected from November 1, 2019, to April 15, 2020, at 17 stroke centers in countries where confinement measures have been in place since March 2020 for the COVID-19 pandemic (Switzerland, Italy, France, Spain, Portugal, Germany, Canada, and United States). This study included 1600 patients treated by EVT for acute ischemic stroke. Date of EVT and symptom onset-to-groin puncture time were collected. Mean number of EVTs performed per hospital per 2-week interval and mean stroke onset-to-groin puncture time were calculated before confinement measures and after confinement measures. Distributions (non-normal) between the 2 groups (before COVID-19 confinement versus after COVID-19 confinement) were compared using 2-sample Wilcoxon rank-sum test. The results show a significant decrease in mean number of EVTs performed per hospital per 2-week interval between before COVID-19 confinement (9.0 [95% CI, 7.8-10.1]) and after COVID-19 confinement (6.1 [95% CI, 4.5-7.7]), ( P <0.001). In addition, there is a significant increase in mean stroke onset-to-groin puncture time ( P <0.001), between before COVID-19 confinement (300.3 minutes [95% CI, 285.3-315.4]) and after COVID-19 confinement (354.5 minutes [95% CI, 316.2-392.7]). Our preliminary analysis indicates a 32% reduction in EVT procedures and an estimated 54-minute increase in symptom onset-to-groin puncture time after confinement measures for COVID-19 pandemic were put into place.

Objectives: The MRI-DRAGON score includes clinical and MRI parameters and demonstrates a high specificity in predicting 3 month outcome in patients with acute ischemic stroke (AIS) treated with intravenous tissue plasminogen activator (IV tPA). The aim of this study was to adapt this score to mechanical thrombectomy (MT) in a large multicenter cohort., Methods: Consecutive cases of AIS treated by MT between January 2015 and December 2017 from three stroke centers were reviewed (n=1077). We derived the MT-DRAGON score by keeping all variables of the MRI-DRAGON score (age, initial National Institutes of Health Stroke Scale score, glucose level, pre-stroke modified Rankin Scale (mRS) score, diffusion weighted imaging-Alberta Stroke Program Early CT score ≤5) and considering the following variables: time to groin puncture instead of onset to IV tPA time and occlusion site. Unfavorable 3 month outcome was defined as a mRS score >2. Score performance was evaluated by c statistics and an external validation was performed., Results: Among 679 included patients (derivation and validation cohorts, n=431 and 248, respectively), an unfavorable outcome was similar between the derivation (51.5%) and validation (58.1%, P=0.7) cohorts, and was significantly associated with all MT-DRAGON parameters in the multivariable analysis. The c statistics for unfavorable outcome prediction was 0.83 (95%CI 0.79 to 0.88) in the derivation and 0.8 (95%CI 0.75 to 0.86) in the validation cohort. All patients (n=55) with an MT-DRAGONscore ≥11 had an unfavorable outcome and 60/63 (95%) patients with an MT-DRAGON score ≤2 points had a favorable outcome., Conclusion: The MT-DRAGON score is a simple tool, combining admission clinical and radiological parameters that can reliably predict 3 month outcome after MT., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

In large vessel occlusion (LVO) stroke, it is unclear whether severity of ischemia is involved in early post-thrombolysis recanalization over and above thrombus site and length. Here we assessed the relationships between perfusion parameters and early recanalization following intravenous thrombolysis administration in LVO patients. From a multicenter registry, we identified 218 thrombolysed LVO patients referred for thrombectomy with both (i) pre-thrombolysis MRI, including diffusion-weighted imaging (DWI), T2*-imaging, MR-angiography and dynamic susceptibility-contrast perfusion-weighted imaging (PWI); and (ii) evaluation of recanalization on first angiographic run or non-invasive imaging ≤ 3 h from thrombolysis start. Infarct core volume on DWI, PWI-DWI mismatch volume and hypoperfusion intensity ratio (HIR; defined as Tmax ≥ 10 s volume/ Tmax ≥ 6 s volume, low HIR indicating milder hypoperfusion) were determined using a commercially available software. Early recanalization occurred in 34 (16%) patients, and multivariable analysis was associated with lower HIR ( P  = 0.006), shorter thrombus on T2*-imaging ( P  < 0.001) and more distal occlusion ( P  = 0.006). However, the relationship between HIR and early recanalization was robust only for thrombus length <14 mm. In summary, the present study disclosed an association between lower HIR and early post-thrombolysis recanalization. Early post-thrombolysis recanalization is therefore determined not only by thrombus site and length but also by severity of ischemia.

Purpose: The susceptibility vessel sign (SVS) has been described on gradient echo (GRE) magnetic resonance imaging (MRI) in acute ischemic stroke patients by large vessel occlusion. The presence of SVS (SVS+) was associated with treatment outcome and stroke etiology with conflicting results. Based on multicenter data from the THRombectomie des Artères CErebrales (THRACE) study, we aimed to determine if the association between SVS and cardioembolic etiology (CE) was independent of GRE sequence parameters., Material and Methods: Patients with a pretreatment brain GRE sequence were identified. Logistic regression tested the association between SVS+, CE, time from onset to imaging and GRE sequence parameters (e.g. echo time, voxel size, field strength). We calculated the sensitivity, specificity, positive and negative predictive values (PPV and NPV) for the SVS to predict a stroke from a CE., Results: An SVS+ was observed in 237 out of 287 (83%) patients. In the univariate analysis, there was a significant association between SVS+ and a CE with an odds ratio (OR) and 95% confidence interval (95% CI) of 2.10 (1.02-4.29), respectively (p = 0.04) but not with GRE sequence parameters. In multivariate analysis, there was an independent relationship between SVS+ and CE (OR [95% CI]: 2.14 [1.02-4.45], p = 0.04). Sensitivity and specificity of SVS+ to predict CE were 0.89 and 0.21, respectively. The PPV and NPV of SVS+ were 0.44 and 0.78, respectively., Conclusion: The presence of SVS is associated to CE, independent of GRE sequence parameters. While the specificity and the PPV of the sign were low, CE seems less likely in the absence of an SVS.

Introduction: To determine the influence of white matter hyperintensity (WMH) burden on functional outcome, rate of symptomatic intracerebral hemorrhage (sICH), and procedural success in patients with acute ischemic stroke (AIS) treated by mechanical thrombectomy (MT) with current stentriever/aspiration devices., Methods: Patients with AIS due to large vessel occlusion (LVO) from the Thrombectomie des Artères Cérébrales (THRACE) trial and prospective cohorts from 2 academic comprehensive stroke centers treated with MT were pooled and retrospectively analyzed. WMH volumes were obtained by semiautomated planimetric segmentation and tested in association with the rate of favorable outcome (90-day functional independence), substantial recanalization after MT, and sICH., Results: A total of 496 participants were included between 2015 and 2018 (50% female, mean age 68.1 ± 15.0 years). Overall, 434 (88%) patients presented with detectable WMH (mean ± SD 4.93 ± 7.7). Patients demonstrated increasingly worse outcomes with increasing WMH volumes (odds ratio [aOR]1.05 per 1-cm 3 increase for unfavorable outcome, 95% confidence interval [CI] 1.01-1.06, p = 0.014). Fifty-seven percent of patients in the first quartile of WMH volume vs 28% in the fourth quartile demonstrated favorable outcome ( p < 0.001). WMH severity was not associated with sICH rate (aOR 0.99, 95% CI 0.93-1.04, p = 0.66), nor did it influence recanalization success (aOR 0.99, 95% CI 0.96-1.02, p = 0.84)., Conclusion: Our study provides evidence that in patients with AIS due to LVO and high burden of WMH as assessed by pretreatment MRI, the safety and efficacy profiles of MT are similar to those in patients with lower WMH burden and confirms that they are at higher risk of unfavorable outcome. Because more than a quarter of patients in the highest WMH quartile experienced favorable 3 months outcome, WMH burden may not be a good argument to deny MT., Clinicaltrialsgov Identifier: NCT01062698., (© 2019 American Academy of Neurology.)

Objectives: We tested whether FLAIR vascular hyperintensities (FVH)-DWI mismatch could identify candidates for thrombectomy most likely to benefit from revascularization., Methods: We retrospectively reviewed 100 patients with proximal MCA occlusion from 18 stroke centers randomized in the IV-thrombolysis plus mechanical thrombectomy arm of the THRACE trial (2010-2015). We tested the associations between successful revascularization on digital subtraction angiography (modified Thrombolysis in Cerebral Infarction 2b/3) and 3-month favorable outcome (modified Rankin Scale score ≤ 2), stratified on FVH-DWI mismatch status, with secondary analyses adjusted on National Institutes of Health Stroke Scale (NIHSS) and DWI lesion volume., Results: FVH-DWI mismatch was present in 79% of patients, with a similar prevalence at 1.5 T (80%) and 3 T (78%). Successful revascularization (74%) was more frequent in patients with FVH-DWI mismatch (63/79, 80%) than in patients without (11/21, 52%), p = 0.01. The OR of favorable outcome for revascularization were 15.05 (95% CI 3.12-72.61, p < 0.001) in patients with FVH-DWI mismatch and 0.83 (95% CI 0.15-4.64, p = 0.84) in patients without FVH-DWI mismatch (p = 0.011 for interaction). Similar results were observed after adjustment for NIHSS (OR = 12.73 [95% CI 2.69-60.41, p = 0.001] and 0.96 [95% CI 0.15-6.30, p = 0.96]) or for DWI volume (OR = 12.37 [95% CI 2.76-55.44, p = 0.001] and 0.91 [95% CI 0.16-5.33, p = 0.92]) in patients with and without FVH-DWI mismatch, respectively., Conclusions: The FVH-DWI mismatch identifies patients likeliest to benefit from revascularization, irrespective of initial DWI lesion volume and clinical stroke severity, and could serve as a useful surrogate marker for penumbral evaluation., Key Points: • The FVH-DWI mismatch, defined by FLAIR vascular hyperintensities (FVH) located beyond the boundaries of the DWI lesion, is associated with large penumbra. • Among stroke patients with proximal middle cerebral artery occlusion referred for thrombectomy, those with FVH-DWI mismatch are most likely to benefit from revascularization. • FVH-DWI mismatch provides an alternative to PWI-DWI mismatch in order to select patients who are candidates for thrombectomy.

Background: Susceptibility vessel sign (SVS) can be a useful MRI biomarker of an occlusion but its relationship with clinical outcomes of acute ischemic stroke (AIS) is yet to be fully elucidated., Objective: To investigate SVS in relation to the clinical outcomes after mechanical thrombectomy using a stent retriever (SR) as first-line approach in patients with AIS., Material and Methods: We included patients with a first-line SR approach for anterior AIS from the the Contact Aspiration vs Stent Retriever for Successful Revascularization (ASTER) and THRombectomie des Artères CErebrales (THRACE) trials when both baseline imaging of SVS and 90-day modified Rankin Scale (mRS) scores were available. Patients were assigned to two groups based on the presence of an SVS (independent core laboratory), and the overall distributions of the mRS score at 90 days (shift analysis) and clinical independence (mRS score ≤2) were compared., Results: 217 patients were included and SVS was diagnosed in 76.0% of cases (n=165, 95% CI 70.4% to 81.7%). After adjustment for potential confounders, SVS+ was significantly associated with 90-day mRS improvement (adjusted common OR=2.75; 95% CI 1.44 to 5.26) and favorable outcome (adjusted common OR=2.76; 95% CI 1.18 to 6.45)., Conclusion: Based on results for patients of the ASTER and THRACE trials receiving first-line SR treatment, SVS was associated with lower disability at 3 months. Large prospective studies using MRI-based thrombus evaluation are warranted., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

Background and Purpose- In acute stroke patients with large vessel occlusion, the goal of intravenous thrombolysis (IVT) is to achieve early recanalization (ER). Apart from occlusion site and thrombus length, predictors of early post-IVT recanalization are poorly known. Better collaterals might also facilitate ER, for instance, by improving delivery of the thrombolytic agent to both ends of the thrombus. In this proof-of-concept study, we tested the hypothesis that good collaterals independently predict post-IVT recanalization before thrombectomy. Methods- Patients from the registries of 6 French stroke centers with the following criteria were included: (1) acute stroke with large vessel occlusion treated with IVT and referred for thrombectomy between May 2015 and March 2017; (2) pre-IVT brain magnetic resonance imaging, including diffusion-weighted imaging, T2*, MR angiography, and dynamic susceptibility contrast perfusion-weighted imaging; and (3) ER evaluated ≤3 hours from IVT start on either first angiographic run or noninvasive imaging. A collateral flow map derived from perfusion-weighted imaging source data was automatically generated, replicating a previously validated method. Thrombus length was measured on T2*-based susceptibility vessel sign. Results- Of 224 eligible patients, 37 (16%) experienced ER. ER occurred in 10 of 83 (12%), 17 of 116 (15%), and 10 of 25 (40%) patients with poor/moderate, good, and excellent collaterals, respectively. In multivariable analysis, better collaterals were independently associated with ER ( P=0.029), together with shorter thrombus ( P<0.001) and more distal occlusion site ( P=0.010). Conclusions- In our sample of patients with stroke imaged with perfusion-weighted imaging before IVT and intended for thrombectomy, better collaterals were independently associated with post-IVT recanalization, supporting our hypothesis. These findings strengthen the idea that advanced imaging may play a key role for personalized medicine in identifying patients with large vessel occlusion most likely to benefit from IVT in the thrombectomy era.

Importance: Reperfusion is a key factor for clinical outcome in patients with acute ischemic stroke (AIS) treated with endovascular thrombectomy (EVT) for large-vessel intracranial occlusion. However, data are scarce on the association between the time from onset and reperfusion results., Objective: To analyze the rate of reperfusion after EVT started at different intervals after symptom onset in patients with AIS., Design, Setting, and Participants: We conducted a meta-analysis of individual patient data from 7 randomized trials of the Highly Effective Reperfusion Using Multiple Endovascular Devices (HERMES) group. This is a multicenter cohort study of the intervention arm of randomized clinical trials included in the HERMES group. Patients with anterior circulation AIS who underwent EVT for M1/M2 or intracranial carotid artery occlusion were included. Each trial enrolled patients according to its specific inclusion and exclusion criteria. Data on patients eligible but not enrolled (eg, refusals or exclusions) were not available. All analyses were performed by the HERMES biostatistical core laboratory using the pooled database. Data were analyzed between December 2010 and April 2015., Main Outcomes and Measures: Successful reperfusion was defined as a modified thrombolysis in cerebral infarction score of 2b/3 at the end of the EVT procedure adjusted for age, occlusion location, pretreatment intravenous thrombolysis, and clot burden score and was analyzed in relation to different intervals (onset, emergency department arrival, imaging, and puncture) using mixed-methods logistic regression., Results: Among the 728 included patients, with a mean (SD) age of 65.4 (13.5) years and of whom 345 were female (47.4%), decreases in rates of successful reperfusion defined as a thrombolysis in cerebral infarction score of 2b/3 were observed with increasing time from admission or first imaging to groin puncture. The magnitude of effect was a 22% relative reduction (odds ratio, 0.78; 95% CI, 0.64-0.95) per additional hour between admission and puncture and a 26% relative reduction (odds ratio, 0.74; 95% CI, 0.59-0.93) per additional hour between imaging and puncture., Conclusions and Relevance: Because the probability of reperfusion declined significantly with time between hospital arrival and groin puncture, we provide additional arguments for minimizing the intervals after symptom onset in anterior circulation acute ischemic stroke.

Background and Purpose- Whether bridging therapy, that is, intravenous thrombolysis [IVT] followed by mechanical thrombectomy, is beneficial as compared with IVT alone in minor stroke (National Institutes of Health Stroke Scale ≤5) with large vessel occlusion is unknown and should be tested in randomized trials. To help select the most appropriate candidates for such trials, we aimed to identify strong predictors of lack of post-IVT early recanalization (ER)-a surrogate marker of poor outcome. Methods- From a large multicenter French registry of patients with large vessel occlusion referred for thrombectomy immediately after IVT start between 2015 and 2017, we extracted 97 minor strokes with ER evaluated on first angiographic run or noninvasive imaging ≤3 hours from IVT start. Thrombus length was measured using the susceptibility vessel sign on T2* imaging. Results- Median National Institutes of Health Stroke Scale was 3 (interquartile range, 2-4), and occlusion sites were proximal (intracranial carotid or M1) and distal (M2) in 50% and 50% of patients, respectively. On pre-IVT MRI, median length of susceptibility vessel sign (visible in 90%) was 9.2 mm (interquartile range, 7.4-13.3). ER was present in 34% of patients, and susceptibility vessel sign length was the only clinical or radiological variable associated with no-ER after stepwise variable selection into a multivariable model (odds ratio, 1.53 per 1-mm increase; 95% CI, 1.21-1.92; P<0.001). The C statistic of susceptibility vessel sign length for no-ER prediction was 0.82 (95% CI, 0.73-0.92), and the optimal cutoff (Youden) was 9 mm. Sensitivity and specificity of this cutoff for no-ER were 67.8% (95% CI, 55.9-79.7) and 84.6% (95% CI, 70.7-98.5), respectively. Conclusions- ER was frequent in this cohort of IVT-treated minor stroke patients with large vessel occlusion considered for thrombectomy, and thrombus length was a powerful independent predictor of no-ER. These findings may help design randomized trials aiming to test bridging therapy versus IVT alone in this population.

Background and Purpose- The acute management of stroke patients requires a fast and efficient screening imaging modality. We compared workflow and functional outcome in acute ischemic stroke patients screened by magnetic resonance imaging (MRI) or computed tomography (CT) before treatment in the THRACE trial (Thrombectomie des Artères Cérébrales), with the emphasis on the duration of the imaging step. Methods- The THRACE randomized trial (June 2010 to February 2015) evaluated the efficacy of mechanical thrombectomy after intravenous tPA (tissue-type plasminogen activator) in ischemic stroke patients with proximal occlusion. The choice of screening imaging modality was left to each enrolling center. Differences between MRI and CT groups were assessed using univariable analysis and the impact of imaging modality on favorable 3-month functional outcome (modified Rankin Scale score of ≤2) was tested using multivariable logistic regression. Results- Four hundred one patients were included (25 centers), comprising 299 MRI-selected and 102 CT-selected patients. Median baseline National Institutes of Health Stroke Scale score was 18 in both groups. MRI scan duration (median [interquartile range]) was longer than CT (MRI: 13 minutes [10-16]; CT: 9 minutes [7-12]; P<0.001). Stroke-onset-to-imaging time (MRI: median 114 minutes [interquartile range, 89-138]; CT: 107 minutes [88-139]; P=0.19), onset-to-intravenous tPA time (MRI: 150 minutes [124-179]; CT: 150 minutes [123-180]; P=0.38) and onset-to-angiography-suite time (MRI: 200 minutes [170-250]; CT: 213 minutes [180-246]; P=0.57) did not differ between groups. Imaging modality was not significantly associated with functional outcome in the multivariable analysis. Conclusions- Although MRI scan duration is slightly longer than CT, MRI-based selection for acute ischemic stroke patients is accomplished within a timeframe similar to CT-based selection, without delaying treatment or impacting functional outcome. This should help to promote wider use of MRI, which has inherent imaging advantages over CT. Clinical Trial Registration- URL: https://www.clinicaltrials.gov . Unique identifier: NCT01062698.

In a prospective study among patients in the THRombectomie des Artères Cerebrales trial, we analyzed the diagnostic accuracy of 2 imaging biomarkers, the 2-layered susceptibility vessel sign and a high overestimation ratio, obtained on pretreatment brain T2* sequences, to identify cardioembolic stroke etiology (107/260 patients). In combination, these 2 biomarkers, on 1.5T or 3T systems (159 and 101 patients, respectively), demonstrated high specificity (0.77 at 1.5T and 1 at 3T) and their simultaneous presence is highly associated with cardioembolism., (© 2019 by American Journal of Neuroradiology.)

Background and Purpose—Whether all acute stroke patients with large vessel occlusion need to undergo intravenous thrombolysis before mechanical thrombectomy (MT) is debated as (1) the incidence of post-thrombolysis early recanalization (ER) is still unclear; (2) thrombolysis may be harmful in patients unlikely to recanalize; and, conversely, (3) transfer for MT may be unnecessary in patients highly likely to recanalize. Here, we determined the incidence and predictors of post-thrombolysis ER in patients referred for MT and derive ER prediction scores for trial design. Methods—Registries from 4 MT-capable centers gathering patients referred for MT and thrombolyzed either on site (mothership) or in a non MT-capable center (drip-and-ship) after magnetic resonance– or computed tomography–based imaging between 2015 and 2017. ER was identified on either first angiographic run or noninvasive imaging. In the magnetic resonance imaging subsample, thrombus length was determined on T2*-based susceptibility vessel sign. Independent predictors of no- ER were identified using multivariable logistic regression models, and scores were developed according to the magnitude of regression coefficients. Similar registries from 4 additional MT-capable centers were used as validation cohort. Results—In the derivation cohort (N=633), ER incidence was ≈20%. In patients with susceptibility vessel sign (n=498), no-ER was independently predicted by long thrombus, proximal occlusion, and mothership paradigm. A 6-point score derived from these variables showed strong discriminative power for no-ER (C statistic, 0.854) and was replicated in the validation cohort (n=353; C statistic, 0.888). A second score derived from the whole sample (including negative T2* or computed tomography–based imaging) also showed good discriminative power and was similarly validated. Highest grades on both scores predicted no-ER with >90% specificity, whereas low grades did not reliably predict ER. Conclusions—The substantial ER rate underlines the benefits derived from thrombolysis in bridging populations. Both prediction scores afforded high specificity for no-ER, but not for ER, which has implications for trial design.

Background and Purpose: Efficacy of endovascular treatment (EVT) for ischemic stroke because of large vessel occlusion may depend on patients' age and stroke severity; we, therefore, developed a prognosis score based on these variables and examined whether EVT efficacy differs between patients with good, intermediate, or poor prognostic score., Methods: A total of 4079 patients with an acute ischemic stroke were identified from the Paris Stroke Consortium registry. We developed the stroke checkerboard (SC) score (SC score=1 point per decade ≥50 years of age and 2 points per 5 points on the National Institutes of Health Stroke Scale) to predict spontaneous outcome. The primary outcome was the adjusted common odds ratio for an improvement in the modified Rankin Scale at 90 days after EVT, in patients with low, intermediate, or high SC scores. To rule out potential selection biases, a nested case-control analysis, with individual matching for all major prognostic factors, was also performed, to compare patients with large vessel occlusion in the anterior circulation treated or not with EVT., Results: In patients untreated with EVT, SC scores <8 were predictive of good outcomes (modified Rankin Scale score, 0-2; area under the curve, 0.87), whereas SC scores >12 were predictive of poor outcomes (modified Rankin Scale score, 4-6; area under the curve, 0.88). In the overall population, there was an interaction between EVT and prognosis group ( P <0.001). EVT was associated with improved outcome in patients with SC scores >12 (common odds ratio, 1.70; 95% confidence interval, 1.13-2.56) and SC scores 8 to 12 (odds ratio, 1.37; 95% confidence interval, 1.11-1.69) but not in patients with SC scores <8 (odds ratio, 0.72; 95% confidence interval, 0.56-0.93). Similar results were obtained in the case-control analysis among 449 patients treated with EVT and 449 matched patients untreated with EVT., Conclusions: In patients stratified with the SC score, EVT was associated with improved functional outcome in older and more severe patients but not in younger and less severe patients., (© 2018 American Heart Association, Inc.)

Background and Purpose: Stroke patients with large diffusion-weighted imaging (DWI) volumes are often excluded from reperfusion because of reckoned futility. In those with DWI volume >70 mL, included in the THRACE trial (Mechanical Thrombectomy After Intravenous Alteplase Versus Alteplase Alone After Stroke), we report the associations between baseline parameters and outcome., Methods: We examined 304 patients with anterior circulation stroke and pretreatment magnetic resonance imaging. Variables were extracted from the THRACE database, and DWI volumes were measured semiautomatically., Results: Among 53 patients with DWI volume >70 mL, 12 had favorable outcome (modified Rankin Scale score, ≤2) at 3 months; they had less coronary disease (0/12 versus 12/38; P =0.046) and less history of smoking (1/10 versus 12/31; P =0.013) than patients with modified Rankin Scale score >2. None of the 8 patients >75 years of age reached modified Rankin Scale score ≤2. Favorable outcome occurred in 12 of 37 M1-occluded patients but in 0 of 16 internal carotid-T/L-occluded patients ( P =0.010). Favorable outcome was more frequent (6/13) when DWI lesion was limited to the superficial middle cerebral artery territory than when it extended to the deep middle cerebral artery territory (6/40; P =0.050)., Conclusions: Stroke patients with DWI lesion >70 mL may benefit from reperfusion therapy, especially those with isolated M1 occlusion or ischemia restricted to the superficial middle cerebral artery territory. The benefit of treatment seems questionable for patients with carotid occlusion or lesion extending to the deep middle cerebral artery territory., (© 2018 American Heart Association, Inc.)

Background: General anaesthesia (GA) during endovascular thrombectomy has been associated with worse patient outcomes in observational studies compared with patients treated without GA. We assessed functional outcome in ischaemic stroke patients with large vessel anterior circulation occlusion undergoing endovascular thrombectomy under GA, versus thrombectomy not under GA (with or without sedation) versus standard care (ie, no thrombectomy), stratified by the use of GA versus standard care., Methods: For this meta-analysis, patient-level data were pooled from all patients included in randomised trials in PuMed published between Jan 1, 2010, and May 31, 2017, that compared endovascular thrombectomy predominantly done with stent retrievers with standard care in anterior circulation ischaemic stroke patients (HERMES Collaboration). The primary outcome was functional outcome assessed by ordinal analysis of the modified Rankin scale (mRS) at 90 days in the GA and non-GA subgroups of patients treated with endovascular therapy versus those patients treated with standard care, adjusted for baseline prognostic variables. To account for between-trial variance we used mixed-effects modelling with a random effect for trials incorporated in all models. Bias was assessed using the Cochrane method. The meta-analysis was prospectively designed, but not registered., Findings: Seven trials were identified by our search; of 1764 patients included in these trials, 871 were allocated to endovascular thrombectomy and 893 were assigned standard care. After exclusion of 74 patients (72 did not undergo the procedure and two had missing data on anaesthetic strategy), 236 (30%) of 797 patients who had endovascular procedures were treated under GA. At baseline, patients receiving GA were younger and had a shorter delay between stroke onset and randomisation but they had similar pre-treatment clinical severity compared with patients who did not have GA. Endovascular thrombectomy improved functional outcome at 3 months both in patients who had GA (adjusted common odds ratio (cOR) 1·52, 95% CI 1·09-2·11, p=0·014) and in those who did not have GA (adjusted cOR 2·33, 95% CI 1·75-3·10, p<0·0001) versus standard care. However, outcomes were significantly better for patients who did not receive GA versus those who received GA (covariate-adjusted cOR 1·53, 95% CI 1·14-2·04, p=0·0044). The risk of bias and variability between studies was assessed to be low., Interpretation: Worse outcomes after endovascular thrombectomy were associated with GA, after adjustment for baseline prognostic variables. These data support avoidance of GA whenever possible. The procedure did, however, remain effective versus standard care in patients treated under GA, indicating that treatment should not be withheld in those who require anaesthesia for medical reasons., Funding: Medtronic., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Background and Purpose: In acute ischemic stroke, whether FLAIR vascular hyperintensities represent good or poor collaterals remains controversial. We hypothesized that extensive FLAIR vascular hyperintensities correspond to good collaterals, as indirectly assessed by the hypoperfusion intensity ratio., Materials and Methods: We included 244 consecutive patients eligible for reperfusion therapy with MCA stroke and pretreatment MR imaging with both FLAIR and PWI. The FLAIR vascular hyperintensity score was based on ASPECTS, ranging from 0 (no FLAIR vascular hyperintensity) to 7 (FLAIR vascular hyperintensities abutting all ASPECTS cortical areas). The hypoperfusion intensity ratio was defined as the ratio of the time-to-maximum >10-second over time-to-maximum >6-second lesion volumes. The median hypoperfusion intensity ratio was used to dichotomize good (low hypoperfusion intensity ratio) versus poor (high hypoperfusion intensity ratio) collaterals. We then studied the association between FLAIR vascular hyperintensity extent and hypoperfusion intensity ratio., Results: Hypoperfusion was present in all patients, with a median hypoperfusion intensity ratio of 0.35 (interquartile range, 0.19-0.48). The median FLAIR vascular hyperintensity score was 4 (interquartile range, 3-5). The FLAIR vascular hyperintensities were more extensive in patients with good collaterals (hypoperfusion intensity ratio ≤0.35) than with poor collaterals (hypoperfusion intensity ratio >0.35; P for Trend = .016). The FLAIR vascular hyperintensity score was independently associated with good collaterals ( P for Trend = .002)., Conclusions: In patients eligible for reperfusion therapy, FLAIR vascular hyperintensity extent was associated with good collaterals, as assessed by the pretreatment hypoperfusion intensity ratio. The ASPECTS assessment of FLAIR vascular hyperintensities could be used to rapidly identify patients more likely to benefit from reperfusion therapy., (© 2018 by American Journal of Neuroradiology.)

Background and Purpose: The susceptibility vessel sign (SVS) on magnetic resonance imaging (MRI) is related to thrombus location, composition, and size in acute stroke. No previous study has determined its inter-MRI scanner variability. We aimed to compare the diagnostic accuracy in-vitro of four different MRI scanners for the characterization of histologic thrombus composition., Methods: Thirty-five manufactured thrombi analogs of different composition that were histologically categorized as fibrin-dominant, mixed, or red blood cell (RBC)-dominant were scanned on four different MRI units with T2* sequence. Nine radiologists, blinded to thrombus composition and MRI scanner model, classified twice, in a 2-week interval, the SVS of each thrombus as absent, questionable, or present. We calculated the weighted kappa with 95% confidence interval (CI), sensitivity, specificity and accuracy of the SVS on each MRI scanner to detect RBC-dominant thrombi., Results: The SVS was present in 42%, absent in 33%, and questionable in 25% of thrombi. The interscanner agreement was moderate to good, ranging from .45 (CI: .37-.52) to .67 (CI: .61-.74). The correlation between the SVS and the thrombus composition was moderate (κ: .50 [CI: .44-.55]) to good κ: .76 ([CI: .72-.80]). Sensitivity, specificity, and accuracy to identify RBC-dominant clots were significantly different between MRI scanners (P < .001)., Conclusion: The diagnostic accuracy of SVS to determine thrombus composition varies significantly among MRI scanners. Normalization of T2*sequences between scanners may be needed to better predict thrombus composition in multicenter studies., (Copyright © 2017 by the American Society of Neuroimaging.)

Background and Purpose: To evaluate hyperacute management of pediatric arterial ischemic stroke, setting up dedicated management pathways is the first recommended step to prove the feasibility and safety of such treatments. A regional pediatric stroke alert protocol including 2 centers in the Paris-Ile-de-France area, France, was established., Methods: Consecutive pediatric patients (28 days-18 years) with confirmed arterial ischemic stroke who had acute recanalization treatment (intravenous r-tPA [recombinant tissue-type plasminogen activator], endovascular procedure, or both) according to the regional pediatric stroke alert were retrospectively reviewed during a 40-month period., Results: Thirteen children, aged 3.7 to 16.6 years, had recanalization treatment. Median time from onset to magnetic resonance imaging was 165 minutes (150-300); 9 out of 13 had large-vessel occlusion. Intravenous r-tPA was used in 11 out of 13 patients, with median time from onset to treatment of 240 minutes (178-270). Endovascular procedure was performed in patients time-out for intravenous r-tPA (n=2) or after intravenous r-tPA inefficiency (n=2). No intracranial or peripheral bleeding was reported. One patient died of malignant stroke; outcome was favorable in 11 out of 12 survivors (modified Rankin Scale score 0-2)., Conclusions: Hyperacute recanalization treatment in pediatric stroke, relying on common protocols and adult/pediatric ward collaboration, is feasible. Larger systematic case collection is encouraged., (© 2017 American Heart Association, Inc.)

Background: In anterior acute ischemic stroke (AAIS) treated with endovascular treatment (EVT), the susceptibility vessel sign (SVS+ or SVS-) is related to recanalization results (TICI 2b/3) and clinical outcome. However, a binary qualitative assessment of thrombus using SVS does not reflect its complex composition. Our aim was to assess whether a quantitative MRI marker, Thrombus-T2* relaxation time, may be assessable in clinical routine and may to predict early successful recanalization after EVT, defined as a TICI 2b/3 recanalization obtained in 2 attempts or less., Material and Methods: Thrombus-T2* relaxation time was prospectively obtained from consecutive AAIS patients treated by EVT (concomitant aspiration and stent retriever). Quantitative values were compared between early recanalization and late or unsuccessful recanalization., Results: Thirty patients with AAIS were included and Thrombus-T2* relaxation time was obtained in all patients. Earlier TICI 2b/3 recanalization were obtained in 22 patients (73%) and was significantly associated with SVS+ (1/8 vs. 16/22, P=0.01) and a shorter Thombus-T2* relaxation time (mean SD, range: 257, 18-50ms vs. 45 9, 35-60ms, P<0.001)., Conclusion: A new quantitative MRI biomarker, the Thrombus-T2* relaxation time is assessable in clinical routine. In a preliminary study of 30 patients, a shorter Thombus-T2* relaxation time is related to earlier recanalization after EVT using combination of stent retriever and aspiration., (Copyright © 2017 Elsevier Masson SAS. All rights reserved.)

Background and Purpose: Triage imaging facilitates the timely recognition of acute stroke with prognostic implications. Improvement in MR acquisition speed is needed given the extreme time constraints before treatment. We compared an ultrafast Echo-Planar FLAIR sequence (EPI-FLAIR) and a conventional FLAIR sequence (cFLAIR) for their diagnostic performances and ability to estimate the age of infarction., Material and Methods: Between June and August 2014, 125 consecutive patients (age 69±18 years, 48% men) admitted for a suspicion of acute (≤48-hrs) stroke were explored by both FLAIR sequences at 1.5-Tesla. EPI-FLAIR (15-sec) and cFLAIR (2-min and 15-sec) were compared by two readers, blinded to clinical data., Results: EPI-FLAIR was less prone to kinetic artefacts than cFLAIR (2-3% vs. 23-49% depending on the reader, P<0.001). Diagnostic concordance was excellent for both readers (к>0.9). Amongst 8 hemorrhages, one subarachnoid hemorrhage presenting as a sudden deficit was missed on EPI-FLAIR sequence. Amongst 60 infarctions, cFLAIR and EPI-FLAIR were concordant in 50 (83%), while signal changes were visible on cFLAIR only in the remaining 10 (17%) cases. Amongst the 43 patients with known onset time (n=17 within 4.5hrs), FLAIR-DWI mismatch identified<4.5-hrs infarction with the same sensitivity (65%) using cFLAIR and EPI-FLAIR, but the positive predictive value (PPV) was higher for cFLAIR than for EPI-FLAIR (73% vs. 50%, P=0.008)., Conclusion: EPI-FLAIR allows a drastic reduction of acquisition time devoted to FLAIR sequence and minimizes motion artifacts. Compared with cFLAIR, it is however associated with increased risk of undiagnosed stroke mimics and lower PPV for identifying<4.5-hrs infarctions., (Copyright © 2017 Elsevier Masson SAS. All rights reserved.)