Trial of Thrombectomy for Stroke with a Large Infarct of Unrestricted Size.

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.).

Intravenous Thrombolysis before Complete Angiographic Reperfusion: Beyond Angiographic Assessment to Target Microvascular Obstruction?

OBJECTIVE: Recent data have suggested that ineffective tissue reperfusion despite successful angiographic reperfusion was partly responsible for unfavorable outcomes after endovascular therapy (EVT) and might be modulated by intravenous thrombolysis (IVT) use before EVT. To specifically decipher the effect played by IVT before EVT, we compared the clinical and safety outcomes of patients who experienced a complete reperfusion at the end of EVT according to IVT use before EVT. METHODS: The Endovascular Treatment in Ischemic Stroke (ETIS) registry is an ongoing, prospective, observational study at 21 centers that perform EVT in France. Patients were included if they had an anterior large vessel occlusion of the intracranial internal carotid artery or middle cerebral artery (M1/M2 segments) and complete reperfusion (expanded Thrombolysis in Cerebral Infarction score = 3) with EVT within 6 hours, between January 2015 and December 2021. The cohort was divided into two groups according to IVT use before EVT, and propensity score matching (PSM) was used to balance the two groups. Primary outcome was the shift in the degree of disability as measured by the modified Rankin Scale (mRS) at 90 days. Secondary outcomes included favorable outcome (mRS 0-2) at 90 days. Safety outcomes included symptomatic intracranial hemorrhage and 90-day mortality. Outcomes were estimated with multivariate logistic models adjusted for age, National Institutes of Health Stroke Scale, Alberta Stroke Program Early CT Score, and time from symptom onset to puncture. RESULTS: Among 5,429 patients included in the ETIS registry, 1,093 were included in the study, including 651 patients with complete recanalization treated with IVT before EVT. After PSM, 488 patients treated with IVT before EVT were compared to 337 patients without IVT. In the matched cohort analysis, the IVT+EVT group had a favorable shift in the overall mRS score distribution (adjusted odds ratio [aOR] = 1.41, 95% confidence interval [CI] = 1.04-1.91, p = 0.023) and higher rates of favorable outcome (61.1% vs 48.7%, aOR = 1.49, 95% CI = 1.02-2.20, p = 0.041) at 90 days compared with the EVT alone group. Rates of symptomatic intracerebral hemorrhage were comparable between both groups (6.0% vs 4.3%, aOR = 1.16, 95% CI = 0.53-2.54, p = 0.709). INTERPRETATION: In clinical practice, even after complete angiographic reperfusion by EVT, prior IVT use improves clinical outcomes of patients without increasing bleeding risk. ANN NEUROL 2024;95:762-773.

Mode of Onset Modifies the Effect of Time to Endovascular Reperfusion on Clinical Outcomes after Acute Ischemic Stroke: An Analysis of the DAWN Trial.

OBJECTIVE: We aimed to assess the impact of time to endovascular thrombectomy (EVT) on clinical outcomes in the DAWN trial, while also exploring the potential effect modification of mode of stroke onset on this relationship. METHODS: The association between every 1-h treatment delay with 90-day functional independence (modified Rankin Scale [mRS] score 0-2), symptomatic intracranial hemorrhage, and 90-day mortality was explored in the overall population and in three modes of onset subgroups (wake-up vs. witnessed vs. unwitnessed). RESULTS: Out of the 205 patients, 98 (47.8%) and 107 (52.2%) presented in the 6 to 12 hours and 12 to 24 hours time window, respectively. Considering all three modes of onset together, there was no statistically significant association between time last seen well to randomization with either functional independence or mortality at 90 days in either the endovascular thrombectomy (mRS 0-2 1-hour delay OR 1.07; 95% CI 0.93-1.24; mRS 6 OR 0.84; 95% CI 0.65-1.03) or medical management (mRS 0-2 1-hour delay OR 0.98; 95% CI 0.80-1.14; mRS 6 1-hour delay OR 0.94; 95% CI 0.79-1.09) groups. Moreover, there was no significant interaction between treatment effect and time (p = 0.439 and p = 0.421 for mRS 0-2 and 6, respectively). However, within the thrombectomy group, the models that tested the association between time last seen well to successful reperfusion (modified Treatment in Cerebral Infarction ≥2b) and 90-day functional independence showed a significant interaction with mode of presentation (p = 0.013). This appeared to be driven by a nominally positive slope for both witnessed and unwitnessed strokes versus a significantly (p = 0.018) negative slope in wake-up patients. There was no association between treatment times and symptomatic intracranial hemorrhage. INTERPRETATION: Mode of onset modifies the effect of time to reperfusion on thrombectomy outcomes, and should be considered when exploring different treatment paradigms in the extended window. ANN NEUROL 2024.

Value of intravenous thrombolysis in endovascular treatment for large-vessel anterior circulation stroke: individual participant data meta-analysis of six randomised trials.

BACKGROUND: Intravenous thrombolysis is recommended before endovascular treatment, but its value has been questioned in patients who are admitted directly to centres capable of endovascular treatment. Existing randomised controlled trials have indicated non-inferiority of endovascular treatment alone or have been statistically inconclusive. We formed the Improving Reperfusion Strategies in Acute Ischaemic Stroke collaboration to assess non-inferiority of endovascular treatment alone versus intravenous thrombolysis plus endovascular treatment. METHODS: We conducted a systematic review and individual participant data meta-analysis to establish non-inferiority of endovascular treatment alone versus intravenous thrombolysis plus endovascular treatment. We searched PubMed and MEDLINE with the terms "stroke", "endovascular treatment", "intravenous thrombolysis", and synonyms for articles published from database inception to March 9, 2023. We included randomised controlled trials on the topic of interest, without language restrictions. Authors of the identified trials agreed to take part, and individual participant data were provided by the principal investigators of the respective trials and collated centrally by the collaborators. Our primary outcome was the 90-day modified Rankin Scale (mRS) score. Non-inferiority of endovascular treatment alone was assessed using a lower boundary of 0·82 for the 95% CI around the adjusted common odds ratio (acOR) for shift towards improved outcome (analogous to 5% absolute difference in functional independence) with ordinal regression. We used mixed-effects models for all analyses. This study is registered with PROSPERO, CRD42023411986. FINDINGS: We identified 1081 studies, and six studies (n=2313; 1153 participants randomly assigned to receive endovascular treatment alone and 1160 randomly assigned to receive intravenous thrombolysis and endovascular treatment) were eligible for analysis. The risk of bias of the included studies was low to moderate. Variability between studies was small, and mainly related to the choice and dose of the thrombolytic drug and country of execution. The median mRS score at 90 days was 3 (IQR 1-5) for participants who received endovascular treatment alone and 2 (1-4) for participants who received intravenous thrombolysis plus endovascular treatment (acOR 0·89, 95% CI 0·76-1·04). Any intracranial haemorrhage (0·82, 0·68-0·99) occurred less frequently with endovascular treatment alone than with intravenous thrombolysis plus endovascular treatment. Symptomatic intracranial haemorrhage and mortality rates did not differ significantly. INTERPRETATION: We did not establish non-inferiority of endovascular treatment alone compared with intravenous thrombolysis plus endovascular treatment in patients presenting directly at endovascular treatment centres. Further research could focus on cost-effectiveness analysis and on individualised decisions when patient characteristics, medication shortages, or delays are expected to offset a potential benefit of administering intravenous thrombolysis before endovascular treatment. FUNDING: Stryker and Amsterdam University Medical Centers, University of Amsterdam.

The Benefit of a Complete over a Successful Reperfusion Decreases with Time.

OBJECTIVE: Time from stroke onset to reperfusion (TSOR) is strongly associated with outcomes after endovascular treatment. A near-to-complete or complete reperfusion (modified Treatment in Cerebral Ischemia [mTICI] 2c-3) is associated with improved outcomes compared with a successful reperfusion (mTICI 2b). However, it is unknown whether this association remains stable as TSOR increases. Therefore, we sought to investigate the association between TSOR and outcomes according to the reperfusion status. METHODS: We analyzed data from the Endovascular Treatment in Ischemic Stroke registry, a prospective, observational, multicentric study of acute ischemic stroke patients treated with endovascular treatment in 21 centers in France. We included patients with anterior occlusions (M1, internal carotid artery, tandem), with a known time of symptom onset. Outcomes were early neurological improvement at 24 hours and favorable outcome (modified Rankin Scale between 0 and 2) at 90 days. RESULTS: Overall, 4,444 patients were analyzed. Compared with a mTICI 2b, a mTICI 2c-3 at 1 hour was associated with higher mean marginal probabilities of early neurological improvement (25.6%, 95% CI 11.7-39.5, p = 0.0003) and favorable outcome (15.2%, 95% CI 3.0-27.4, p = 0.0143), and progressively declined with TSOR. The benefit of a mTICI 2c-3 over a mTICI 2b was no longer significant regarding the rates of early neurological improvement and favorable outcome after a TSOR of 414 and 344 minutes, respectively. INTERPRETATION: The prognostic value of a complete over a successful reperfusion progressively declined with time, and no difference regarding the rates of favorable outcome was observed between a complete and successful reperfusion beyond 5.7 hours. ANN NEUROL 2023;93:934-941.

Thrombectomy with or without Intravenous Thrombolytics in Basilar Artery Occlusion.

OBJECTIVE: Two randomized trials demonstrated the benefit of endovascular therapy (EVT) in patients suffering from a stroke due to a basilar artery occlusion (BAO). However, intravenous thrombolytic (IVT) use before EVT was low in these trials, questioning the added value of this treatment in this setting. We sought to investigate the efficacy and safety of EVT alone compared to IVT + EVT in stroke patients with a BAO. METHODS: We analyzed data from the Endovascular Treatment in Ischemic Stroke registry, a prospective, observational, multicenter study of acute ischemic stroke patients treated with EVT in 21 centers in France between 1 January 2015 and 31 December 2021. We included patients with BAO and/or intracranial vertebral artery occlusion and compared patients treated with EVT alone versus IVT + EVT after propensity score (PS) matching. Variables selected for the PS were pre-stroke mRS, dyslipidemia, diabetes, anticoagulation, admission mode, baseline NIHSS and ASPECTS, type of anesthesia, and time from symptom onset to puncture. Efficacy outcomes were good functional outcome (modified Rankin Scale [mRS] 0-3) and functional independence (mRS 0-2) at 90 days. Safety outcomes were symptomatic intracranial hemorrhages and all-cause mortality at 90 days. RESULTS: Among 385 patients, 243 (134 EVT alone and 109 IVT + EVT) were included after PS matching. There was no difference between EVT alone and IVT + EVT regarding good functional outcome (adjusted odd ratio [aOR] labeling = 1.27, 95% confidence interval [CI], 0.68-2.37, p = 0.45) and functional independence (aOR = 1.50, 95% CI, 0.79-2.85, p = 0.21). Symptomatic intracranial hemorrhage and all-cause mortality were also similar between the two groups (aOR = 0.42, 95% CI, 0.10-1.79, p = 0.24 and aOR = 0.56, 95% CI, 0.29-1.10, p = 0.09, respectively). INTERPRETATION: In this PS matching analysis, EVT alone seemed to lead to similar neurological recovery than IVT + EVT, with comparable safety profile. However, given our sample size and the observational nature of this study, further studies are needed to confirm these findings. ANN NEUROL 2023;94:596-604.

Role of Brain Imaging in the Prediction of Intracerebral Hemorrhage Following Endovascular Therapy for Acute Stroke.

Currently most acute ischemic stroke patients presenting with a large vessel occlusion are treated with endovascular therapy (EVT), which results in high rates of successful recanalization. Despite this success, more than half of EVT-treated patients are significantly disabled 3 months later partly due to the occurrence of post-EVT intracerebral hemorrhage. Predicting post-EVT intracerebral hemorrhage is important for individualizing treatment strategies in clinical practice (eg, safe initiation of early antithrombotic therapies), as well as in selecting the optimal candidates for clinical trials that aim to reduce this deleterious outcome. Emerging data suggest that brain and vascular imaging biomarkers may be particularly relevant since they provide insights into the ongoing acute stroke pathophysiology. In this review/perspective, we summarize the accumulating literature on the role of cerebrovascular imaging biomarkers in predicting post-EVT-associated intracerebral hemorrhage. We focus on imaging acquired before EVT, during the EVT procedure, and in the early post-EVT time frames when new therapeutic therapies could be tested. Accounting for the complex pathophysiology of post-EVT-associated intracerebral hemorrhage, this review may provide some guidance for future prospective observational or therapeutic studies.

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

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

Parenchymal Hemorrhage Rate Is Associated with Time to Reperfusion and Outcome.

OBJECTIVE: Despite a 90% reperfusion rate, only 50% of patients with anterior circulation large vessel occlusion-related acute ischemic stroke (LVO-AIS) have a functional recovery at 3 months. Parenchymal hematoma (PH) is a predictor of poor outcome after endovascular treatment (EVT). We aim to investigate the relationship between the delay from onset to reperfusion, the occurrence of PH, and functional outcome. METHODS: The Endovascular Treatment in Ischemic Stroke (ETIS) registry is an ongoing prospective observational study. Data were analyzed from the subgroup of patients who underwent a successful EVT defined by a modified Thrombolysis in Cerebral Infarction (mTICI) score 2b-3. We assessed the factors associated with PH, (ie, PH1 or PH2 grade according to the European Collaborative Acute Stroke Study 2 (ECASS) classification of hemorrhagic transformation), then evaluated the relationships between PH, delay from onset to reperfusion, and functional recovery defined by a modified Rankin Scale (mRS) of 0-2. RESULTS: We analyzed 2,919 patients with an LVO-related AIS who underwent a successful EVT. Overall, 13.3% of the participant experienced a PH. The rate of PH increased by 2.5% (95% CI 1.5%-3.6%, p < 0.001) for every additional hour of onset to reperfusion delay and was, by comparison with the other study patients, consistently associated with a lower rate of functional recovery 19.7% (95% CI 11.6%-27.7%, p < 0.001) irrespective of time from onset to reperfusion. INTERPRETATION: Our results demonstrate that PH rate is associated with the delay from onset to reperfusion and participates in the relationship between time to reperfusion and outcome. Time is Bleeding. ANN NEUROL 2022;92:882-887.

Dual-layer carotid stenting for symptomatic carotid web: Results from the Caroweb study.

BACKGROUND & PURPOSE: Carotid Web (CaW) is a growingly recognized cause of ischemic stroke, associated with a high recurrence risk. Several therapeutic strategies have been proposed as a tertiary prevention including carotid stenting, endarterectomy and antithrombotic medications. Among these, carotid stenting with dual-layer stent may be promising to adequately cover the focal arterial dysplasia. Our aim was to investigate the safety and efficacy of the Casper stent in the treatment of symptomatic CaW. METHODS: We conducted a retrospective analysis of consecutive patients presenting with a symptomatic CaW and included in the ongoing prospective observational multicenter CAROWEB registry. The study period was January 2015 to December 2021. Inclusion criteria were CaW treated with dual-layer Casper stent. Patients treated with other types of carotid stent, endarterectomy or antithrombotic medication were excluded. Clinical and radiological initial data and outcomes were recorded. RESULTS: twenty-seven patients (with 28 caw) were included. median age was 52 (iqr: 46-68). median delay between index cerebrovascular event and cervical stenting was 9 days (IQR: 6-101). In all cases, the cervical carotid stenting was successfully performed. No major perioperative complication was recorded. No recurrent stroke or transient ischemic attack was observed during a median follow-up time of 272 days (IQR: 114-635). Long-term imaging follow-up was available in 25/28 (89.3%) stented CaW with a median imaging follow-up of 183 days (IQR: 107-676; range: 90-1542). No in-stent occlusion or stenosis was detected. CONCLUSION: In this study, carotid stenting with dual-layer Casper stent in the treatment of symptomatic CaW was effective regarding stroke recurrence prevention and safe, without procedural nor delayed detected adverse event. However, the optimal therapeutic approach of symptomatic CaW still needs to be explored through randomized trials.

Clinical Results of the Advanced Neurovascular Access Catheter System Combined With a Stent Retriever in Acute Ischemic Stroke (SOLONDA).

BACKGROUND: The Advanced Neurovascular Access (ANA) thrombectomy system is a novel stroke thrombectomy device comprising a self-expanding funnel designed to reduce clot fragmentation by locally restricting flow while becoming as wide as the lodging artery. Once deployed, the ANA device allows distal aspiration combined with a stent retriever to mobilize the clot into the funnel where it remains copped during extraction. We investigated the safety and efficacy of ANA catheter system. METHODS: SOLONDA (Solitaire in Combination With the ANA Catheter System as Manufactured by Anaconda) was a prospective, open, single-arm, multicenter trial with blinded assessment of the primary outcome by an independent core lab. Patients with anterior circulation vessel occlusion admitted within 8 hours from symptom onset were eligible. The primary end point was successful reperfusion (modified Thrombolysis in Cerebral Infarction score 2b-3) with ≤3 passes of the ANA device in combination with stent retriever, before the use of rescue therapy in the intention to treat population. Primary predefined analysis was noninferiority as compared to the performance end point observed in HERMES (High Effective Reperfusion Using Multiple Endovascular Devices). RESULTS: After enrollment of 74 patients, an interim analysis was conducted, and the trial Steering Committee decided to terminate recruitment due to safety and performance objectives were reached. Mean age was 71.6 (SD 8.9) years, 46.6% women and median National Institutes of Health Stroke Scale on admission 14 (interquartile range, 10-19). Successful reperfusion within 3 passes before rescue therapy was achieved in 60/72 (83.3% [95% CI, 74.7%-91.9%]) with a rate of complete reperfusion (modified Thrombolysis in Cerebral Infarction score 2c-3) of 60% (95% CI, 48.4%-71.1%; 43/72 patients). After noninferiority was confirmed (P<0.01), the ANA device also showed superiority in the rate of successful reperfusion with ≤3 passes (P=0.02). First-pass successful recanalization rate was 55.6% (95% CI, 44.1%-67.0%), with a first-pass complete recanalization rate of 38.9% (95% CI, 27.6%-50.1%). Rescue therapy to obtain a modified Thrombolysis in Cerebral Infarction score 2b-3 was needed in 12/72 (17%) patients. At 90 days, the rate of favorable functional outcome (modified Rankin Scale score 0-2) was 57.5% (95% CI, 46.2%-68.9%), and the rate of excellent functional outcome (modified Rankin Scale score 0-1) was 45.2% (95% CI, 33.8%-56.6%). The rate of severe adverse device related was 1.4%. CONCLUSIONS: In this clinical experience, the ANA device achieved a high rate of complete recanalization with a preliminary good safety profile and favorable 90 days clinical outcomes. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT04095767.

Collateral Circulation in Thrombectomy for Stroke After 6 to 24 Hours in the DAWN Trial.

BACKGROUND AND PURPOSE: Collaterals govern the pace and severity of cerebral ischemia, distinguishing fast or slow progressors and corresponding therapeutic opportunities. The fate of sustained collateral perfusion or collateral failure is poorly characterized. We evaluated the nature and impact of collaterals on outcomes in the late time window DAWN trial (Diffusion-Weighted Imaging or Computed Tomography Perfusion Assessment With Clinical Mismatch in the Triage of Wake-Up and Late Presenting Strokes Undergoing Neurointervention With Trevo). METHODS: The DAWN Imaging Core Lab prospectively scored collateral grade on baseline computed tomography angiography (CTA; endovascular and control arms) and digital subtraction angiography (DSA; endovascular arm only), blinded to all other data. CTA collaterals were graded with the Tan scale and DSA collaterals were scored by ASITN grade (American Society of Interventional and Therapeutic Neuroradiology collateral score). Descriptive statistics characterized CTA collateral grade in all DAWN subjects and DSA collaterals in the endovascular arm. The relationship between collateral grade and day 90 outcomes were separately analyzed for each treatment arm. RESULTS: Collateral circulation to the ischemic territory was evaluated on CTA (n=144; median 2, 0-3) and DSA (n=57; median 2, 1-4) before thrombectomy in 161 DAWN subjects (mean age 69.8±13.6 years; 55.3% women; 91 endovascular therapy, 70 control). CTA revealed a broad range of collaterals (Tan grade 3, n=64 [44%]; 2, n=45 [31%]; 1, n=31 [22%]; 0, n=4 [3%]). DSA also showed a diverse range of collateral grades (ASITN grade 4, n=4; 3, n=22; 2, n=27; 1, n=4). Across treatment arms, baseline demographics, clinical variables except atrial fibrillation (41.6% endovascular versus 25.0% controls, P=0.04), and CTA collateral grades were balanced. Differences were seen across the 3 levels of collateral flow (good, fair, poor) for baseline National Institutes of Health Stroke Scale, blood glucose <150, diabetes, previous ischemic stroke, baseline and 24-hour core infarct volume, baseline and 24-hour Alberta Stroke Program Early CT Score, dramatic infarct progression, final Thrombolysis in Cerebral Infarction 2b+, and death. Collateral flow was a significant predictor of 90-day modified Rankin Scale score of 0 to 2 in the endovascular arm, with 43.7% (31/71) of subjects with good collaterals, 30.8% (16/52) of subjects with fair collaterals, and 17.7% (6/34) of subjects with poor collaterals reaching modified Rankin Scale score of 0 to 2 at 90 days (P=0.026). CONCLUSIONS: DAWN subjects enrolled at 6 to 24 hours after onset with limited infarct cores had a wide range of collateral grades on both CTA and DSA. Even in this late time window, better collaterals lead to slower stroke progression and better functional outcomes. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02142283.

Repeat Flow Diversion for Cerebral Aneurysms Failing Prior Flow Diversion: Safety and Feasibility From Multicenter Experience.

BACKGROUND: Aneurysmal persistence after flow diversion (FD) occurs in 5% to 25% of aneurysms, which may necessitate retreatment. There are limited data on safety/efficacy of repeat FD-a frequently utilized strategy in such cases. METHODS: A series of consecutive patients undergoing FD retreatment from 15 centers were reviewed (2011-2019), with inclusion criteria of repeat FD for the same aneurysm at least 6 months after initial treatment, with minimum of 6 months post-retreatment imaging. The primary outcome was aneurysmal occlusion, and secondary outcome was safety. A multivariable logistic regression model was constructed to identify predictors of incomplete occlusion (90%-99% and <90% occlusion) versus complete occlusion (100%) after retreatment. RESULTS: Ninety-five patients (median age, 57 years; 81% women) harboring 95 aneurysms underwent 198 treatment procedures. Majority of aneurysms were unruptured (87.4%), saccular (74.7%), and located in the internal carotid artery (79%; median size, 9 mm). Median elapsed time between the first and second treatment was 12.2 months. Last available follow-up was at median 12.8 months after retreatment, and median 30.6 months after the initial treatment, showing complete occlusion in 46.2% and near-complete occlusion (90%-99%) in 20.4% of aneurysms. There was no difference in ischemic complications following initial treatment and retreatment (4.2% versus 4.2%; P>0.99). On multivariable regression, fusiform morphology had higher nonocclusion odds after retreatment (odds ratio [OR], 7.2 [95% CI, 1.97-20.8]). Family history of aneurysms was associated with lower odds of nonocclusion (OR, 0.18 [95% CI, 0.04-0.78]). Likewise, positive smoking history was associated with lower odds of nonocclusion (OR, 0.29 [95% CI, 0.1-0.86]). History of hypertension trended toward incomplete occlusion (OR, 3.10 [95% CI, 0.98-6.3]), similar to incorporated branch into aneurysms (OR, 2.78 [95% CI, 0.98-6.8]). CONCLUSIONS: Repeat FD for persistent aneurysms carries a reasonable success/safety profile. Satisfactory occlusion (100% and 90%-99% occlusion) was encountered in two-thirds of patients, with similar complications between the initial and subsequent retreatments. Fusiform morphology was the strongest predictor of retreatment failure.

Perfusion Imaging and Clinical Outcome in Acute Ischemic Stroke with Large Core.

OBJECTIVE: Mechanical thrombectomy (MT) is not recommended for acute stroke with large vessel occlusion (LVO) and a large volume of irreversibly injured tissue ("core"). Perfusion imaging may identify a subset of patients with large core who benefit from MT. METHODS: We compared two cohorts of LVO-related patients with large core (>50 ml on diffusion-weighted-imaging or CT-perfusion using RAPID), available perfusion imaging, and treated within 6 hours from onset by either MT + Best Medical Management (BMM) in one prospective study, or BMM alone in the pre-MT era from a prospective registry. Primary outcome was 90-day modified Rankin Scale ≤2. We searched for an interaction between treatment group and amount of penumbra as estimated by the mismatch ratio (MMRatio = critical hypoperfusion/core volume). RESULTS: Overall, 107 patients were included (56 MT + BMM and 51 BMM): Mean age was 68 ± 15 years, median core volume 99 ml (IQR: 72-131) and MMRatio 1.4 (IQR: 1.0-1.9). Baseline clinical and radiological variables were similar between the two groups, except for a higher intravenous thrombolysis rate in the BMM group. The MMRatio strongly modified the clinical outcome following MT (pinteraction < 0.001 for continuous MMRatio); MT was associated with a higher rate of good outcome in patients with, but not in those without, MMRatio>1.2 (adjusted OR [95% CI] = 6.8 [1.7-27.0] vs 0.7 [0.1-6.2], respectively). Similar findings were present for MMRatio ≥1.8 in the subgroup with core ≥70 ml. Parenchymal hemorrhage on follow-up imaging was more frequent in the MT + BMM group regardless of the MMRatio. INTERPRETATION: Perfusion imaging may help select which patients with large core should be considered for MT. Randomized studies are warranted. ANN NEUROL 2021;90:417-427.

Leptomeningeal enhancement on post-contrast FLAIR images for early diagnosis of Susac syndrome.

BACKGROUND: Leptomeningeal enhancement (LME) is a key feature of Susac syndrome (SuS) but is only occasionally depicted on post-contrast T1-weighted images (T1-WI). OBJECTIVE: As post-contrast fluid-attenuated inversion recovery (FLAIR) may be more sensitive, our aim was to assess LME in SuS on this sequence. METHODS: From 2010 to 2020, 20 patients with definite SuS diagnosis were retrospectively enrolled in this multicentre study. Two radiologists independently assessed the number of LME on post-contrast FLAIR and T1-WI acquisitions performed before any treatment. A chi-square test was used to compare both sequences and the interrater agreement was calculated. RESULTS: Thirty-five magnetic resonance imagings (MRIs) were performed before treatment, including 19 post-contrast FLAIR images in 17 patients and 25 post-contrast T1-WI in 19 patients. In terms of patients, LME was observed on all post-contrast FLAIR, contrary to post-contrast T1-WI (17/17 (100%) vs. 15/19 (79%), p < 0.05). In terms of sequences, LME was observed on all post-contrast FLAIR, contrary to post-contrast T1-WI (19/19 (100%) vs. 16/25 (64%), p < 0.005). LME was disseminated at both supratentorial (19/19) and infratentorial (18/19) levels on post-contrast FLAIR, contrary to post-contrast T1-WI (3/25 and 9/25, respectively). Interrater agreement was excellent for post-contrast FLAIR (κ = 0.95) but only moderate for post-contrast T1-WI (κ = 0.61). CONCLUSION: LME was always observed and easily visible on post-contrast FLAIR images prior to SuS treatment. In association with other MRI features, it is highly indicative of SuS.

Dural arteriovenous fistulas in cerebral venous thrombosis: Data from the International Cerebral Venous Thrombosis Consortium: Data from the International Cerebral Venous Thrombosis Consortium.

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

Reproducibility of volume analysis of dynamic susceptibility contrast perfusion-weighted imaging in untreated glioblastomas.

PURPOSE: Despite a high variability, the hotspot method is widely used to calculate the cerebral blood volume (CBV) of glioblastomas on DSC-MRI. Our aim was to investigate inter- and intra-observer reproducibility of parameters calculated with the hotspot or a volume method and that of an original parameter assessing the fraction of pixels in the tumour volume displaying rCBV > 2: %rCBV > 2. METHODS: Twenty-seven consecutive patients with untreated glioblastoma (age: 63, women: 11) were retrospectively included. Three observers calculated the maximum tumour CBV value (rCBVmax) normalized with a reference ROI in the contralateral white matter (CBVWM) with (i) the hotspot method and (ii) with a volume method following tumour segmentation on 3D contrast-enhanced T1-WI. From this volume method, %rCBV > 2 was also assessed. After 8-12 weeks, one observer repeated all delineations. Intraclass (ICC) and Lin's (LCC) correlation coefficients were used to determine reproducibility. RESULTS: Inter-observer reproducibility of rCBVmax was fair with the hotspot and good with the volume method (ICC = 0.46 vs 0.65, p > 0.05). For CBVWM, it was fair with the hotspot and excellent with the volume method (0.53 vs 0.84, p < 0.05). Reproducibility of one pairwise combination of observers was significantly better for both rCBVmax and CBVWM (LCC = 0.33 vs 0.75; 0.52 vs 0.89, p < 0.05). %rCBV > 2 showed excellent inter- and intra-observer reproducibility (ICC = 0.94 and 0.91). CONCLUSION: Calculated in glioblastomas with a volume method, rCBVmax and CBVWM yielded good to excellent reproducibility but only fair with the hotspot method. Overall, the volume analysis offers a highly reproducible parameter, %rCBV > 2, that could be promising during the follow-up of such heterogeneous tumours.

Interdisciplinary management of acute ischaemic stroke: Current evidence training requirements for endovascular stroke treatment. Position Paper from the ESC Council on Stroke and the European Association for Percutaneous Cardiovascular Interventions with the support of the European Board of Neurointervention.

This ESC Council on Stroke/EAPCI/EBNI position paper summarizes recommendations for training of cardiologists in endovascular treatment of acute ischaemic stroke. Interventional cardiologists adequately trained to perform endovascular stroke interventions could complement stroke teams to provide the 24/7 on call duty and thus to increase timely access of stroke patients to endovascular treatment. The training requirements for interventional cardiologists to perform endovascular therapy are described in details and should be based on two main principles: (i) patient safety cannot be compromised, (ii) proper training of interventional cardiologists should be under supervision of and guaranteed by a qualified neurointerventionist and within the setting of a stroke team. Interdisciplinary cooperation based on common standards and professional consensus is the key to the quality improvement in stroke treatment.

Subarachnoid haemorrhage due to the rupture of a high flow aneurysm developed on an intradural artery feeding a jugulotympanic paraganglioma.

BACKGROUND: Head and neck paragangliomas are extradural masses rarely associated with subarachnoid haemorrhage. CASE: This case, for the first time, reports a fatal subarachnoid haemorrhage due to the rupture of a high-flow aneurysm located on an intradural artery feeding a jugulotympanic paraganglioma. Interestingly, this aneurysm was not present on an angiogram performed 7 years before, during the pre-surgical embolisation of the tumour. CONCLUSIONS: To avoid fatal consequences, a preventive investigation of potential aneurysms located on intradural vessels feeding paragangliomas may be suggested.

Mismatch Profile Influences Outcome After Mechanical Thrombectomy.

BACKGROUND AND PURPOSE: Mechanical thrombectomy (MT) is the recommended treatment for acute ischemic stroke caused by anterior circulation large vessel occlusion. However, despite a high rate of reperfusion, the clinical response to successful MT remains highly variable in the early time window where optimal imaging selection criteria have not been established. We hypothesize that the baseline perfusion imaging profile may help forecast the clinical response to MT in this setting. METHODS: We conducted a prospective multicenter cohort study of patients with large vessel occlusion-related acute ischemic stroke treated by MT within 6 hours. Treatment decisions and the modified Rankin Scale evaluation at 3 months were performed blinded to the results of baseline perfusion imaging. Study groups were defined a posteriori based on predefined imaging profiles: target mismatch (TMM; core volume <70 mL/mismatch ratio >1.2 and mismatch volume >10 mL) versus no TMM or mismatch (MM; mismatch ratio >1.2 and volume >10 mL) versus no MM. Functional recovery (modified Rankin Scale, 0-2) at 3 months was compared based on imaging profile at baseline and whether reperfusion (modified Thrombolysis in Cerebral Infarction 2bc3) was achieved. RESULTS: Two hundred eighteen patients (mean age, 71±15 years; median National Institutes of Health Stroke Scale score, 17 [interquartile range, 12-21]) were enrolled. Perfusion imaging profiles were 71% TMM and 82% MM. The rate of functional recovery was 54% overall. Both TMM and MM profiles were independently associated with a higher rate on functional recovery at 3 months Adjusted odds ratios were 3.3 (95% CI, 1.4-7.9) for TMM and 5.9 (95% CI, 1.8-19.6) for MM. Reperfusion (modified Thrombolysis in Cerebral Infarction 2bc3) was achieved in 86% and was more frequent in TMM and MM patients. Reperfusion was associated with a higher rate of functional recovery in MM and TMM patients but not among those with no MM. CONCLUSIONS: In this cohort study, about 80% of the patients with a large vessel occlusion-related acute ischemic stroke had evidence of penumbra, regardless of infarction volume. Perfusion imaging profiles predict the clinical response to MT.