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Purpose: Our purpose was to assess the efficacy and safety of the pRESET LITE stent retriever (Phenox, Bochum, Germany), designed for medium vessel occlusion (MeVO) in acute ischemic stroke (AIS) patients with a primary MeVO., Methods: We performed a retrospective analysis of the MAD MT Consortium, an integration of prospectively maintained databases at 37 academic institutions in Europe, North America, and Asia, of AIS patients who underwent mechanical thrombectomy with the pRESET LITE stent retriever for a primary MeVO. We subcategorized occlusions into proximal MeVOs (segments A1, M2, and P1) vs. distal MeVOs/DMVO (segments A2, M3-M4, and P2). We reviewed patient and procedural characteristics, as well as angiographic and clinical outcomes., Results: Between September 2016 and December 2021, 227 patients were included (50% female, median age 78 [65-84] years), of whom 161 (71%) suffered proximal MeVO and 66 (29%) distal MeVO. Using a combined approach in 96% of cases, successful reperfusion of the target vessel (mTICI 2b/2c/3) was attained in 85% of proximal MeVO and 97% of DMVO, with a median of 2 passes (IQR: 1-3) overall. Periprocedural complications rate was 7%. Control CT at day 1 post-MT revealed a hemorrhagic transformation in 63 (39%) patients with proximal MeVO and 24 (36%) patients with DMVO, with ECASS-PH type hemorrhagic transformations occurring in 3 (1%) patients. After 3 months, 58% of all MeVO and 63% of DMVO patients demonstrated a favorable outcome (mRS 0-2)., Conclusion: Mechanical thrombectomy using the pRESET LITE in a combined approach with an aspiration catheter appears effective for primary medium vessel occlusions across several centers and physicians., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Although pretreatment radiographic biomarkers are well established for hemorrhagic transformation (HT) following successful mechanical thrombectomy (MT) in large vessel occlusion (LVO) strokes, they are yet to be explored for medium vessel occlusion (MeVO) acute ischemic strokes. We aim to investigate pretreatment imaging biomarkers representative of collateral status, namely the hypoperfusion intensity ratio (HIR) and cerebral blood volume (CBV) index, and their association with HT in successfully recanalized MeVOs. A prospectively collected registry of acute ischemic stroke patients with MeVOs successfully recanalized with MT between 2019 and 2023 was retrospectively reviewed. A multivariate logistic regression for HT of any subtype was derived by combining significant univariate predictors into a forward stepwise regression with minimization of Akaike information criterion. Of 60 MeVO patients successfully recanalized with MT, HT occurred in 28.3% of patients. Independent factors for HT included: diabetes mellitus history (p = 0.0005), CBV index (p = 0.0071), and proximal versus distal occlusion location (p = 0.0062). A multivariate model with these factors had strong diagnostic performance for predicting HT (area under curve [AUC] 0.93, p < 0.001). Lower CBV indexes, distal occlusion location, and diabetes history are significantly associated with HT in MeVOs successfully recanalized with MT. Of note, HIR was not found to be significantly associated with HT., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany.)

Background and Purpose: In large vessel occlusion (LVO) stroke patients, relative cerebral blood flow (rCBF)<30% volume thresholds are commonly used in treatment decisions. In the early time window, nearly infarcted but salvageable tissue volumes may lead to pretreatment overestimates of infarct volume, and thus potentially exclude patients who may otherwise benefit from intervention. Our multisite analysis aims to explore the strength of relationships between widely used pretreatment CT parameters and clinical outcomes for early window stroke patients., Methods: Patients from two sites in a prospective registry were analyzed. Patients with LVOs, presenting within 3 hours of last known well, and who were successfully reperfused were included. Primary short-term neurological outcome was percent National Institutes of Health Stroke Scale (NIHSS) change from admission to discharge. Secondary long-term outcome was 90-day modified Rankin score. Spearman's correlations were performed. Significance was attributed to p-value ≤.05., Results: Among 73 patients, median age was 66 (interquartile range 54-76) years. Among all pretreatment imaging parameters, rCBF<30%, rCBF<34%, and rCBF<38% volumes were significantly, inversely correlated with percentage NIHSS change (p<.048). No other parameters significantly correlated with outcomes., Conclusions: Our multisite analysis shows that favorable short-term neurological recovery was significantly correlated with rCBF volumes in the early time window. However, modest strength of correlations provides supportive evidence that the applicability of general ischemic core estimate thresholds in this subpopulation is limited. Our results support future larger-scale efforts to liberalize or reevaluate current rCBF parameter thresholds guiding treatment decisions for early time window stroke patients., (© 2023 American Society of Neuroimaging.)

Introduction: First pass effect (FPE), achievement of complete recanalization (mTICI 2c/3) with a single pass, is a significant predictor of favorable outcomes for endovascular treatment (EVT) in large vessel occlusion stroke (LVO). However, data concerning the impact on functional outcomes and predictors of FPE in medium vessel occlusions (MeVO) are scarce., Patients and Methods: We conducted an international retrospective study on MeVO cases. Multivariable logistic modeling was used to establish independent predictors of FPE. Clinical and safety outcomes were compared between the two study groups (FPE vs non-FPE) using logistic regression models. Good outcome was defined as modified Rankin Scale 0-2 at 3 months., Results: Eight hundred thirty-six patients with a final mTICI ⩾ 2b were included in this analysis. FPE was observed in 302 patients (36.1%). In multivariable analysis, hypertension (aOR 1.55, 95% CI 1.10-2.20) and lower baseline NIHSS score (aOR 0.95, 95% CI 0.93-0.97) were independently associated with an FPE. Good outcomes were more common in the FPE versus non-FPE group (72.8% vs 52.8%), and FPE was independently associated with favorable outcome (aOR 2.20, 95% CI 1.59-3.05). 90-day mortality and intracranial hemorrhage (ICH) were significantly lower in the FPE group, 0.43 (95% CI, 0.25-0.72) and 0.55 (95% CI, 0.39-0.77), respectively., Conclusion: Over 2/3 of patients with MeVOs and FPE in our cohort had a favorable outcome at 90 days. FPE is independently associated with favorable outcomes, it may reduce the risk of any intracranial hemorrhage, and 3-month mortality., 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: Dr. Regenhardt serves on a DSMB for a trial sponsored by Rapid Medical, serves as site PI for studies sponsored by Penumbra and Microvention, and receives stroke research grant funding from the National Institutes of Health, Society of Vascular and Interventional Neurology, and Heitman Stroke Foundation. Dr. Guenego reports consultancy for Rapid Medical and Phenox, not directly related to the present work. Prof. Clarençon reports conflicts of interest with Medtronic, Balt Extrusion (consultant), ClinSearch (core lab), Penumbra, Stryker (payment for reading) and Artedrone (Board); all not directly related to the present work. Dr. Henninger received support from NINDS NS131756, during the conduct of the study. Dr. Liebeskind is consultant as Imaging Core Lab to Cerenovus, Genentech, Medtronic, Stryker, Rapid Medical. Dr. Yeo reports Advisory work for AstraZeneca, Substantial support from NMRC Singapore and is a medical advisor for See-mode, Cortiro and Sunbird Bio, with equity in Ceroflo. All unrelated to the present work. Dr. Griessenauer reports a proctoring agreement with Medtronic and research funding by Penumbra. Dr. Marnat reports conflicts of interest with Microvention Europe, Stryker Neurovascular, Balt (consulting), Medtronic, Johnson & Johnson and Phenox (paid lectures), all not directly related to the present work. Dr. Nguyen reports advisory board with Idorsia and Brainomix. All other others do not report any conflict of interests related to this work.

Background and Purpose: Acute ischemic stroke due to large vessel occlusion (AIS-LVO) is a major cause of functional dependence. Collateral status (CS) is an important determinant of functional outcomes. Pretreatment CT perfusion (CTP) parameters serve as reliable surrogates of CS. Penumbra Salvage Index (PSI) is another parameter predictive of functional outcomes in AIS-LVO. The aim of this study is to assess the relationship of pretreatment CTP parameters with PSI., Methods: In this prospectively collected, retrospectively reviewed multicenter analysis, inclusion criteria were as follows: (1) CT angiography confirmed middle cerebral artery (MCA) M1-segment and proximal M2-segment occlusion from 9/1/2017 to 9/22/2022; (2) diagnostic CTP; and (3) available diagnostic Magnetic resonance Imaging (MRI) diffusion-weighted images. Pearson correlation analysis was performed to assess the association between cerebral blood volume (CBV) index and hypoperfusion intensity ratio (HIR) with PSI. p value ≤.05 was considered statistically significant., Results: In total, 131 patients (n = 86, M1 and n = 45, proximal M2 occlusion) met our inclusion criteria. CBV index showed a modest positive correlation with PSI (r = 0.34, p<.001) in patients with proximal MCA occlusion. Similar trends were noted in subgroup analysis of patients with M1 occlusion, and proximal M2 occlusion. Whereas, HIR did not have a strong trend or correlation with PSI., Conclusion: CBV index correlates with PSI, whereas HIR does not. Future studies are needed to expand our understanding of the adjunct role of CBV index with other similar pretreatment CTP-based markers in clinical evaluation and decision-making in patients with MCA occlusion., (© 2023 American Society of Neuroimaging.)

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.

Background: The first-pass effect in endovascular thrombectomy (EVT) has been associated with better clinical outcomes and decreased stroke progression in large vessel occlusion but has not been evaluated in distal, medium vessel occlusions (DMVOs)., Objective: To assess the impact on clinical outcome and stroke progression of the modified first-pass effect (defined as a successful first-pass [modified Thrombolysis In Cerebral Infarction 2b/2c/3] revascularization) in patients who underwent EVT for a primary DMVOs., Methods: We collected data from consecutive patients who underwent EVT for a primary DMVO at a single large academic center. We compared the rate of good clinical outcome (modified Rankin Scale of 0-2 at 3 months) and stroke progression between patients who demonstrated modified first-pass effect (mFPE) vs those who did not (no-mFPE)., Results: Between January 2018 and January 2021, we included 60 patients who underwent EVT for an acute ischemic stroke with a primary DMVO. Overall, mFPE was achieved in 32% (19/60) of EVTs. The mFPE was associated with a higher rate of good clinical outcome compared with no-mFPE (89% vs 46%, odds ratio = 16.04 [2.23-115.39], P = .006 in multivariate analysis). Final stroke volume was less among mFPE patients (6.9 mL [4.7-13.6] vs 23 mL [14.6-47], P = .001) as was stroke progression (6.8 mL [4-12.1] vs 17.8 mL [8.1-34.9], P = .016). The mFPE was still associated with higher rates of good clinical outcome when compared with patients reaching an modified Thrombolysis In Cerebral Infarction score ≥2b in more than 1 pass (89% vs 53%; odds ratio = 7.37 [1.43-38.08], P = .017)., Conclusion: The mFPE may be associated with better clinical outcomes and lower stroke progression in DMVO., (Copyright © Congress of Neurological Surgeons 2022. All rights reserved.)

Background: Half of the patients with large vessel occlusion (LVO)-related acute ischemic stroke (AIS) who undergo endovascular reperfusion are dead or dependent at 3 months. We hypothesize that in addition to established prognostic factors, baseline imaging profile predicts outcome among reperfusers., Methods: Consecutive patients receiving endovascular treatment (EVT) within 6 hours after onset with Thrombolysis In Cerebral Infarction (TICI) 2b, 2c and 3 revascularization were included. Poor outcome was defined by a modified Rankin scale (mRS) 3-6 at 90 days. No mismatch (NoMM) profile was defined as a mismatch (MM) ratio ≤1.2 and/or a volume <10 mL on pretreatment imaging., Results: 187 patients were included, and 81 (43%) had a poor outcome. Median delay from stroke onset to the end of EVT was 259 min (IQR 209-340). After multivariable logistic regression analysis, older age (OR 1.26, 95% CI 1.06 to 1.5; p=0.01), higher National Institutes of Health Stroke Scale (NIHSS) (OR 1.15, 95% CI 1.06 to 1.25; p<0.0001), internal carotid artery (ICA) occlusion (OR 3.02, 95% CI 1.2 to 8.0; p=0.021), and NoMM (OR 4.87, 95% CI 1.09 to 22.8; p=0.004) were associated with poor outcome. In addition, post-EVT hemorrhage (OR 3.64, 95% CI 1.5 to 9.1; p=0.04) was also associated with poor outcome., Conclusions: The absence of a penumbra defined by a NoMM profile on baseline imaging appears to be an independent predictor of poor outcome after reperfusion. Strategies aiming to preserve the penumbra may be encouraged to improve these patients' outcomes., Competing Interests: Competing interests: JMO Medtronic, Aptoll, Abbvie, BMS-Pfizer, Medtronic French Ministry of Health. JJH Ischema View, Medtronic, Microvention. LC Boehringer Ingelheim, BMS-Pfizer, Boehringer. NR Fullbright Foundation, Harvard University and Philippe Foundation. MMa Boerhinger Ingelheim, Medtronic, Air Liquide, Amgen, Acticor Biotech. AG Member of Editorial Board JNIS Fellows. IS AstraZeneca, BMS-Pfizer, Bayer, Boehringer Ingelheim, Medtronic, NovoNordisc. TT Canon Medical, grant from French research secretary. GWA IschemaView, Genentech, grant from NIHCC Medtronic Cerenovus Stryker MIVI Neuroscience, Microvention. SC IschemaView., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Background and Purpose: This study evaluated whether quantitative measurement of collaterals by the hypoperfusion intensity ratio (HIR) on baseline computed tomography perfusion (CTP) correlated with infarct growth and clinical outcome after successful endovascular recanalization of acute ischemic stroke (AIS) caused by primary distal medium vessel occlusions (DMVO)., Methods: We performed a retrospective analysis of consecutive AIS patients who underwent an initial CTP and were successfully recanalized by thrombectomy (modified thrombolysis In cerebral infarction 2b or 3) for DMVO. We evaluated the association of baseline HIR with infarct growth and clinical outcome., Results: Between January 2018 and January 2021, 40 patients with an AIS caused by a DMVO were successfully recanalized by MT (65%, 26/40 female, median age 72 years, range 65-83 years). Baseline HIR was strongly correlated with infarct growth after successful recanalization (r = 0.501, p = 0.001). An HIR<0.3 was the optimal threshold for good collaterals using ROC analysis. Patients with HIR ≥ 0.3 had higher infarct growth compared to HIR < 0.3 (23.8 mL, IQR: 9.1-45.1 vs. 7.2 mL, interquartile range (IQR): 4.2-11.7, relative risk 7.9, p = 0.024 in multivariate analysis); their clinical outcome was poorer in univariate analysis (75%, 21/28 patients with a 3 months modified Rankin scale of 0-2 vs. 33%,4/12, p < 0.017, odds ratio (OR) 6.0, 1.37-26.20) but it did not remain significant in multivariate analysis (p = 0.107)., Conclusion: Good collaterals on initial CTP assessed by an HIR < 0.3 are associated with less infarct growth after successful recanalization of AIS caused by a DMVO., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany.)

Purpose: To evaluate the safety and efficacy of the Tigertriever 13 (Rapid Medical, Yoqneam, Israel) stent retriever in acute ischemic stroke (AIS) patients with primary or secondary distal, medium vessel occlusions (DMVO)., Methods: We performed a retrospective analysis of all consecutive AIS patients who underwent thrombectomy with the Tigertriever13 for DMVO. Patients' characteristics were reviewed, procedural complications, angiographic (modified thrombolysis in cerebral infarction score [mTICI]) and clinical (modified Rankin Scale [mRS]) outcomes were documented., Results: Between November 2019 and November 2020, 16 patients with 17 DMVO were included (40% female, median age 60 [50-65] years). The Tigertriever13 was used in 11/17 (65%, median NIHSS of 8 [6-15]) primary DMVO and in 6/17 (35%, median NIHSS of 20 [13-24]) cases of secondary DMVO after a proximal thrombectomy. The successful reperfusion rate (mTICI 2b, 2c, 3) was 94% (16/17) for the dedicated vessel. At day 1, CT imaging showed a subarachnoid hemorrhage in 29% of the cases and a parenchymal hematoma in 12%. At 3 months, 65% of the patients (11/17) had a favorable outcome (mRS 0-2)., Conclusion: Mechanical thrombectomy using the Tigertriever13 appears to be safe and effective for DMVO. Clinical and anatomical results are in line with those of patients with proximal occlusions.

Objective: Good clinical outcome predictors have been emphasized in mechanical thrombectomy (MT) for acute ischemic stroke (AIS) with large vessel occlusion. MT for distal, medium vessel occlusions (DMVO) is still debated. We sought to assess the factors associated with clinical outcome after MT for DMVO., Methods: We retrospectively analyzed the data of consecutive patients who underwent MT for a primary DMVO in 1 large academic center and aimed to identify the baseline clinical, imaging, and MT factors associated with good clinical outcome (defined as modified Rankin scale score of 0-2) at 3 months., Results: Between January 2018 and January 2021, 61 patients underwent a MT for an AIS with a primary DMVO. Overall, good clinical outcome was achieved in 56% (34 of 61) of our patients. In multivariate analysis, an older age (odds ratio [OR] 0.89 [95% confidence interval 0.83-0.96], P = 0.003), longer puncture to recanalization time (OR 0.97 [0.93-0.99], P = 0.033), and higher baseline core volume (OR 0.84 [0.75-0.94], P = 0.003) decreased the probability of good clinical outcomes, while a final complete (or near-) recanalization (modified Thrombolysis In Cerebral Infarction [mTICI] score 2c-3) increased the probability of good outcome (OR 14.19 [1.99-101.4], P = 0.008)., Conclusions: An older age, a longer puncture to recanalization time, and a higher baseline core volume decreased the probability of good clinical outcomes, while successful recanalization (mTICI 2c-3) was associated with better outcomes after MT for DMVO., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Purpose: Acute ischemic stroke (AIS) secondary to a basilar artery occlusion (BAO) carries a poor prognosis, especially in cases of severe symptoms, such as coma at presentation. Despite a lack of evidence, mechanical thrombectomy (MT) is often performed as the procedural risks are felt to be minimal compared to the natural history. We sought to evaluate MT efficacy and safety in comatose BAO patients., Methods: We performed a retrospective analysis of a multicenter prospective cohort of consecutive AIS patients with BAO who underwent MT. We compared baseline characteristics between comatose and noncomatose BAO patients, as well as clinical outcomes (modified Rankin scale, mRS 0-3 at 3 months). Using a multivariate logistic regression, we examined the population of comatose patients for baseline predictive factors of mortality., Results: We included 269 patients, 72 (27%) comatose and 197 (73%) non-comatose. Despite similar recanalization rates between comatose and non-comatose patients (83% vs. 90% p = 0.221), comatose patient long-term outcomes were dramatically worse (11% mRS 0-3 vs. 54%, p < 0.0001) and mortality was higher (64% vs. 34%, p < 0.0001). Baseline predictors of mortality at 3 months among comatose BAO patients after multivariate analysis were the following: male sex (odds ratio, OR 31.20, 2.57-378.52, p = 0.007), older age (OR 1.13, 1.04-1.24, p = 0.007) and higher serum glucose levels (OR 1.54, 1.07-2.21, p = 0.019)., Conclusion: Thrombectomy is technically effective for BAO patients presenting with coma; however, the long-term favorable outcome remains poor. Male sex, old age and hyperglycemia were predictors of mortality in these patients., (© 2021. Springer-Verlag GmbH, DE part of Springer Nature.)

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 (p interaction  < 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., (© 2021 American Neurological Association.)

Background: Acute ischemic stroke patients with a large-vessel occlusion but mild symptoms (NIHSS ≤ 6) pose a treatment dilemma between medical management and endovascular thrombectomy., Aims: To evaluate the differences in clinical outcomes of endovascular thrombectomy-eligible patients with target-mismatch perfusion profiles who undergo either medical management or endovascular thrombectomy., Methods: Forty-seven patients with acute ischemic stroke due to large-vessel occlusion, NIHSS ≤ 6, and a target-mismatch perfusion imaging profile were included. Patients underwent medical management or endovascular thrombectomy following treating neurointerventionalist and neurologist consensus. The primary outcome measure was NIHSS shift. Secondary outcome measures were symptomatic intracranial hemorrhage, in-hospital mortality, and 90-day mRS scores. The primary intention-to-treat and as-treated analyses were compared to determine the impact of crossover patient allocation on study outcome measures., Results: Forty-seven patients were included. Thirty underwent medical management (64%) and 17 underwent endovascular thrombectomy (36%). Three medical management patients underwent endovascular thrombectomy due to early clinical deterioration. Presentation NIHSS ( P  = 0.82), NIHSS shift ( P  = 0.62), and 90-day functional independence (mRS 0-2; P  = 0.25) were similar between groups. Endovascular thrombectomy patients demonstrated an increased overall rate of intracranial hemorrhage (35.3% vs. 10.0%; P  = 0.04), but symptomatic intracranial hemorrhage was similar between groups ( P  = 0.25). In-hospital mortality was similar between groups ( P  = 0.46), though all two deaths in the medical management group occurred among crossover patients. Endovascular thrombectomy patients demonstrated a longer length of stay (7.6 ± 7.2 vs. 4.3 ± 3.9 days; P  = 0.04) and a higher frequency of unfavorable discharge to a skilled-nursing facility ( P  = 0.03) rather than home ( P  = 0.05)., Conclusions: Endovascular thrombectomy may pose an unfavorable risk-benefit profile over medical management for endovascular thrombectomy-eligible acute ischemic stroke patients with mild symptoms, which warrants a randomized trial in this subpopulation.

Background and Purpose: Choice of anesthesia type on outcome for mechanical thrombectomy (MT) in acute ischemic stroke remains controversial. The goal of our research was to study the impact of anesthesia strategy on the delay, angiographic and neurological outcome of MT performed under general anesthesia (GA) vs. conscious sedation (CS)., Methods: This prospective, single-center observational study included patients with anterior circulation large vessel occlusion (ACLVO) strokes treated with MT within 6 hours of symptom onset. All time metrics were evaluated. Angiographic and clinical outcomes were assessed by recanalization rate (mTICI) and 3-month functional independence (mRs). Complications and mortality rate were recorded as safety outcomes., Results: In total, 303 consecutive thrombectomies were performed, 86.8% under GA. NIHSS was higher in GA, with median of 19.0 for GA and 16.5 for CS (P = 0.049). Median time from arrival in hospital (door) to groin puncture was 83 min (IQR = 45.0-109.5) for GA compared to 72 min (IQR = 35.0-85.3) for CS, P = 0.170). Median time from arrival in the angiosuite to groin puncture was 20 min (IQR = 15.0-29.0) for GA compared to 15 min (IQR = 10.0-20.0) for CS, P = 0.017). There were no significant differences in recanalization time metrics, successful revascularization rate, functional independence and mortality rate at three months., Conclusions: GA induced a 5 to 10 minutes delay for groin puncture, without impact on recanalization time metrics, or neurological outcome at 3 months. Our results demonstrate that a well-organized workflow is associated with reasonable delay in performing GA for MT, without effect on outcome compared to sedation., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)

Background: International dose reference levels are lacking for mechanical thrombectomy in acute ischemic stroke patients with large vessel occlusions. We studied whether radiation dose-reduction systems (RDS) could effectively reduce exposure and propose achievable levels., Materials and Methods: We retrospectively included consecutive patients treated with thrombectomy on a biplane angiography system (BP) in five international, high-volume centers between January 2014 and May 2017. Institutional Review Board approvals were obtained. Technical, procedural, and clinical characteristics were assessed. Efficacy, safety, radiation dose, and contrast load were compared between angiography systems with and without RDS. Multivariate analyses were adjusted according to Bonferroni's correction. Proposed international achievable cutoff levels were set at the 75th percentile., Results: Out of the 1096 thrombectomized patients, 520 (47%) were treated on a BP equipped with RDS. After multivariate analysis, RDS significantly reduced dose-area product (DAP) (91 vs 140 Gy cm 2 , relative effect 0.74 (CI 0.66; 0.83), 35% decrease, p < 0.001) and air kerma (0.46 vs 0.97 Gy, relative effect 0.63 (CI 0.56; 0.71), 53% decrease, p < 0.001) with 75th percentile levels of 148 Gy cm 2 and 0.73 Gy, respectively. There was no difference in contrast load, rates of successful recanalization, complications, or clinical outcome., Conclusion: Radiation dose-reduction systems can reduce DAP and air kerma by a third and a half, respectively, without affecting thrombectomy efficacy or safety. The respective thresholds of 148 Gy cm 2 and 0.73 Gy represent achievable levels that may serve to optimize current and future radiation exposure in the setting of acute ischemic stroke treatment. As technology evolves, we expect these values to decrease., Key Points: • Internationally validated achievable levels may help caregivers and health authorities better assess and reduce radiation exposure of both ischemic stroke patients and treating staff during thrombectomy procedures. • Radiation dose-reduction systems can reduce DAP and air kerma by a third and a half, respectively, without affecting thrombectomy efficacy or safety in the setting of acute ischemic stroke due to large vessel occlusion.

Background and Purpose- Hypoperfusion intensity ratio (HIR) is associated with collateral status in acute ischemic stroke patients with anterior circulation large vessel occlusion. We assessed whether HIR was correlated to patient eligibility for mechanical thrombectomy (MT). Methods- We performed a retrospective cohort study of consecutive acute ischemic stroke patients with a proximal middle cerebral artery or internal carotid artery occlusion who underwent MT triage with computed tomography or magnetic resonance perfusion imaging. Clinical data, ischemic core (mL), HIR (defined as time-to-maximum [TMax] >10 seconds/TMax >6 seconds), mismatch volume between core and penumbra, and MT details were assessed. Primary outcome was favorable HIR collateral score (HIR <0.4) between patients who underwent MT (MT+) and those who did not (MT-) according to American Heart Association guidelines both in the <6 hours and 6 to 24 hours windows. Secondary outcomes were favorable HIR score in MT- subgroups (National Institutes of Health Stroke Scale <6 versus core >70 mL) and core-penumbra mismatch volumes. Patients who did not meet guidelines were not included. Results- We included 197 patients (145 MT+ and 52 MT-). MT+ patients had a significantly lower median HIR compared with MT- patients (0.4 [interquartile range, 0.2-0.5] versus 0.6 [interquartile range, 0.5-0.8]; P<0.001) and a higher mismatch volume (96 versus 27 mL, P<0.001). Among MT- patients, 43 had a core >70 mL, and 9 had a National Institutes of Health Stroke Scale <6. MT- patients with National Institutes of Health Stroke Scale <6 had a lower HIR than MT- patients with core >70 mL (0.2 [interquartile range, 0.2-0.3] versus 0.7 [interquartile range, 0.6-0.8], P<0.001) but their HIR was not significantly different that MT+ patients. Conclusions- Patients who meet American Heart Association guidelines for thrombectomy are more likely to have favorable collaterals (low HIR). HIR may be used as a marker of eligibility for MT triage.