Search

Background: To define optimal parameters for the evaluation of vessel visibility in intracranial stents (ICS) and flow diverters (FD) using photon-counting detector computed tomography angiography (PCD-CTA) with spectral reconstructions., Methods: We retrospectively analyzed consecutive patients with implanted ICS or FD, who received a PCD-CTA between April 2023 and March 2024. Polyenergetic, virtual monoenergetic, pure lumen, and iodine reconstructions with different keV levels (40, 60, and 80) and reconstruction kernels (body vascular [Bv]48, Bv56, Bv64, Bv72, and Bv76) were evaluated by two radiologists with regions of interests and Likert scales. Reconstructions were compared in descriptive analysis., Results: In total, twelve patients with nine FDs and six ICSs were analyzed. In terms of quantitative image quality, sharper kernels as Bv64 and Bv72 yielded increased image noise and decreased signal-to-noise and contrast-to-noise ratios compared to the smoothest kernel Bv48 (p = 0.001). Among the different keV levels and kernels, readers selected the 40 keV level (p = 0.001) and sharper kernels (in the majority of cases Bv72) as the best to visualize the in-stent vessel lumen. Assessing the different spectral reconstructions virtual monoenergetic and iodine reconstructions proved to be best to evaluate in-stent vessel lumen (p = 0.001)., Conclusion: PCD-CTA and spectral reconstructions with sharper reconstruction kernels and a low keV level of 40 seem to be beneficial to achieve optimal image quality for the evaluation of ICS and FD. Iodine and virtual monoenergetic reconstructions were superior to pure lumen and polyenergetic reconstructions to evaluate in-stent vessel lumen., Relevance Statement: PCD-CTA offers the opportunity to reduce the need for invasive angiography serving as follow-up examination after intracranial stent (ICS) or flow diverter (FD) implantation., Key Points: Neuroimaging of intracranial vessels with implanted stents and flow diverters is limited by artifacts. Twelve patients with nine flow diverters and six intracranial stents underwent photon-counting detector computed tomography angiography (PCD-CTA). In-stent vessel lumen visibility improved using sharp reconstruction kernels and a low keV level. Virtual monoenergetic and iodine reconstructions were best to evaluate in-stent vessel lumen., Competing Interests: Declarations. Ethics approval and consent to participate: Written informed consent was waived by the Institutional Review Board due to the retrospective nature of this study as accorded by the Local Ethics Committee of the medical faculty of RWTH Aachen, Aachen, Germany (local registration no: EK 24-238). Consent for publication: Not applicable. Competing interests: The authors declare that they have no competing interests., (© 2025. The Author(s).)

Background: Surveys are increasingly used in neurointervention to gauge physicians' and patients' attitudes, practice patterns, and 'real-world' treatment strategies, particularly in conditions for which few, or no evidence-based, recommendations exist. While survey-based studies can provide valuable insights into real-world problems and management strategies, there is an inherent risk of bias., Objective: To assess key themes, sample characteristics, response metrics, and report frequencies of quality indicators of neurointerventional surveys., Methods: A systematic review compliant with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline was performed. The PubMed database was searched for neurointerventional surveys published between 2000 and 2023. Survey topics, design, respondent characteristics, and survey quality criteria suggested by the Consensus-Based Checklist for Reporting of Survey Studies (CROSS) were assessed and described using descriptive statistics. Response rates and numbers of participants were further assessed for their dependence on sample characteristics and survey methodologies., Results: A total of 122 surveys were included in this analysis. The number of surveys published each year increased steeply between 2000 (n=1) and 2023 (n=14). The most common survey topics were stroke (51/122, 41.8%) and aneurysm treatment (49/122, 40.2%). The median response rate was 58.5% (IQR=30.4-86.3), with a median number of respondents of 79 (IQR=50-201). Sixty-eight of 122 (55.7%) surveys published the questionnaire used for data collection. Only a subset of studies reported response rates (n=89, 73%), data collection time period (n=91, 74.6%), and strategies to prevent duplicate responses (n=57, 46.7%)., Conclusion: Surveys are increasingly used by neurointerventional researchers, particularly to assess real-world practice patterns in endovascular stroke and aneurysm treatment. Adapting best-practice guidelines like the CROSS checklist might improve homogeneity and quality in neurointerventional survey research., Competing Interests: Competing interests: CSW and SLB have received travel grants to attend conferences. AS has received a stipend from the Swiss Society of Radiology for his research fellowship., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: This multicenter study evaluated the safety and efficacy of coated flow diverters (cFDs) for the treatment of ruptured intracranial aneurysms., Methods: Consecutive patients treated with different cFDs for ruptured aneurysms under tirofiban at eight neurovascular centers between 2016 and 2023 were retrospectively analyzed. The majority of patients were loaded with dual antiplatelet therapy after the treatment. Aneurysm occlusion was determined using the O'Kelly-Marotta (OKM) grading scale. Primary outcome measures were major procedural complications and aneurysmal rebleeding during hospitalization., Results: The study included 60 aneurysms (posterior circulation: 28 (47%)) with a mean size of 5.8±4.7 mm. Aneurysm morphology was saccular in 28 (47%), blister-like in 12 (20%), dissecting in 13 (22%), and fusiform in 7 (12%). Technical success was 100% with a mean of 1.1 cFDs implanted per aneurysm. Adjunctive coiling was performed in 11 (18%) aneurysms. Immediate contrast retention was observed in 45 (75%) aneurysms. There was 1 (2%) major procedural complication (a major stroke, eventually leading to death) and no aneurysmal rebleeding. A good outcome (modified Rankin Scale 0-2) was achieved in 40 (67%) patients. At a mean follow-up of 6 months, 27/34 (79%) aneurysms were completely occluded (OKM D), 3/34 (9%) had an entry remnant (OKM C), and 4/34 (12%) had residual filling (OKM A or B). There was 1 (3%) severe in-stent stenosis during follow-up that was treated with balloon angioplasty., Conclusions: Treatment of ruptured aneurysms with cFDs was reasonably safe and efficient and thus represents a valid treatment option, especially for complex cases., Competing Interests: Competing interests: CK serves as consultant for Acandis GmbH (Pforzheim, Germany) and as proctor for MicroVention Inc./Sequent Medical (Aliso Viejo, CA, USA). TL previously served as proctor for MicroVention Inc./Sequent Medical (Aliso Viejo, CA, USA), CERUS Endovascular (Fremont, CA, USA), Phenox (Bochum, Germany), Stryker (Kalamazoo, MI, USA), and Medtronic (Dublin, Ireland). DZ is on the speaker’s bureau of Philips (Amsterdam, The Netherlands) and lecturer for Amboss GmbH (Cologne, Germany). FD serves as consultant/ proctor for MicroVention Inc./Sequent Medical, Balt (Irvine, CA, USA), Cerenovus/Johnson&Johnson (Irvine, CA, USA); received speakers honoraria from Cerenovus/ Johnson&Johnson, Acandis, Asahi (Tokyo, Japan), Q Apel (Fremont, CA, USA), Penumbra (Alameda, CA, USA), Medtronic, Stryker; received scientific grants from Cerenovus/ Johnson&Johnson. The other authors declare that they have no competing interests., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: This multicenter study evaluates the safety and efficacy of coated flow diverters (cFDs) for the treatment of cerebral aneurysms under single antiplatelet therapy (SAPT)., Methods: This is a retrospective, observational study of 41 patients (median age: 58 years) with 41 aneurysms (median size: 7 mm, 29 [71%] saccular, 9 [22%] ruptured) treated with cFDs at four neurovascular centers between 2020 and 2023. Scheduled cases received continuous SAPT starting seven days before the procedure. Emergency cases were treated with tirofiban followed by SAPT loading. The safety endpoint was ischemic complications occurring during the procedure and within four months of clinical follow-up., Results: The Pipeline Vantage or Flex Shield was used in 26 (63%) procedures, the FRED X in 12 (29%), the p48/64 Hydrophilic Polymer Coating in 2 (5%), and the Derivo Embolization Device 2heal in 1 (2%). Single antiplatelet therapy consisted of prasugrel in 27 (66%) patients, ticagrelor in 9 (22%), and ASA in 5 (12%). There were 2 (5%) early ischemic complications (one minor stroke and one transient ischemic attack). There were no late ischemic complications in the four-month follow-up of 35 patients. The six dropouts included four nontreatment-related deaths after subarachnoid hemorrhage and two patients with a poor outcome after subarachnoid hemorrhage. Complete and favorable occlusion rates (median: 7 months) were 75% (27/36) and 89% (32/36), respectively., Conclusions: Coated flow diverter implantation in the setting of SAPT was safe and effective and warrants confirmation in a prospective comparative trial., 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: CK serves as consultant for Acandis GmbH (Pforzheim, Germany) and as proctor for MicroVention Inc./Sequent Medical (Aliso Viejo, CA, USA). TL serves or previously served as proctor for MicroVention Inc./Sequent Medical (Aliso Viejo, CA, USA), CERUS Endovascular (Fremont, CA, USA), Phenox (Bochum, Germany), Stryker (Kalamazoo, MI, USA), and Medtronic (Dublin, Ireland). DZ is on the speaker’s bureau of Philips (Amsterdam, the Netherlands) and lecturer for Amboss GmbH (Cologne, Germany). FD serves as consultant/ proctor for MicroVention Inc./Sequent Medical (Aliso Viejo, CA, USA), Balt (Irvine, CA, USA), Cerenovus/Johnson&Johnson (Irvine, CA, USA); received speakers honoraria from Cerenovus/Johnson&Johnson (Irvine, CA, USA), Acandis (Pforzheim, Germany), Asahi (Tokyo, Japan), Q`Apel (Fremont, CA, USA), Penumbra (Alameda, CA, USA), Medtronic (Dublin, Ireland), Stryker (Kalamazoo, MI, USA); received scientific grants from Cerenovus/Johnson&Johnson (Irvine, CA, USA). SH received travel support by Medtronic (Dublin, Ireland).

Purpose: The clinical importance and management of vasospasm as a complication during endovascular stroke treatment (EVT) has not been well studied. We sought to investigate the effect of adding nimodipine to the guiding catheter flush (GCF) to prevent vasospasm during EVT., Methods: This is a single-center retrospective analysis including patients with EVT (stent-retriever and/or distal aspiration) treated for anterior or posterior circulation intracranial vessel occlusion from January 2018 to June 2023. Exclusion criteria were intracranial or extracranial stenosis, intra-arterial alteplase, patient age over 80 years. Study groups were patients with (nimo+) and without (nimo-) nimodipine in the GCF. They were compared for occurrence of vasospasm as primary endpoint and clinical outcome in univariate analysis., Results: 477 patients were included in the analysis (nimo+ n = 94 vs. nimo- n = 383). Nimo+ patients experienced less vasospasm during EVT (e.g. vasospasm in target vessel n (%): nimo- = 113 (29.6) vs. nimo+ = 9 (9.6), p < 0.001; extracranial vasospasm, n (%): nimo- = 68 (17.8) vs. nimo+ = 7 (7.4), p = 0.017). Patients of the two study groups had a comparable clinical outcome (90 day mRS, median (IQR): 3 (1-6) for both groups, p = 0.896). In general, patients with anterior circulation target vessel occlusion (TVO) experienced more vasospasm (anterior circ. TVO 38.7% vs. posterior circ. 7.5%, p = 0.006)., Conclusion: Prophylactic adding of nimodipine reduces the risk of vasospasm during EVT without affecting the clinical outcome. Patients with anterior circulation TVO experienced more vasospasm compared to posterior circulation TVO., Competing Interests: Declarations Conflict of interest L.J. Sommer, J. Jesser, O. Nikoubashman, T.N. Nguyen, J. Pinho, A. Reich, M. Wiesmann and C.S. Weyland declare that they have no competing interests. Ethical standards Informed consent: Written informed consent was waived by the local ethics committee. Ethical approval: Ethical approval for the stroke database was provided by the local ethics committee (Ethikkommission der Medizinischen Fakultät der Universität Aachen; 35/333). Written informed consent was waived in view of the retrospective study design., (© 2024. The Author(s).)

Background and Aim: The clinical importance and management of vasospasm as a complication during endovascular stroke treatment (EVT) has not been well studied. We sought to investigate current expert opinions in neurointervention and therapeutic strategies of iatrogenic vasospasm during EVT., Methods: We conducted an anonymous international online survey (4 April 2023 to 15 May 2023) addressing treatment standards of neurointerventionalists (NIs) practising EVT. Several illustrative cases of patients with vasospasm during EVT were shown. Two study groups were compared according to the NI's opinion regarding the potential influence of vasospasm on patient outcome after EVT using descriptive analysis., Results: In total, 534 NI from 56 countries responded, of whom 51.5% had performed >200 EVT. Vasospasm was considered a complication potentially influencing the patient's outcome by 52.6% (group 1) whereas 47.4% did not (group 2). Physicians in group 1 more often added vasodilators to their catheter flushes during EVT routinely (43.7% vs 33.9%, p=0.033) and more often treated severe large-vessel vasospasm with vasodilators (75.3% vs 55.9%; p<0.001), as well as extracranial vasospasm (61.4% vs 36.5%, p<0.001) and intracranial medium-vessel vasospasm (27.1% vs 11.2%, p<0.001), compared with group 2. In case of a large-vessel vasospasm and residual and amenable medium-vessel occlusion during EVT, the study groups showed different treatment strategies. Group 2 continued the EVT immediately more often, without initiating therapy to treat the vasospasm first (9.6% vs 21.1%, p<0.001)., Conclusion: There is disagreement among NIs about the clinical relevance of vasospasm during EVT and its management. There was a higher likelihood of use of preventive and active vasodilator treatment in the group that perceived vasospasm as a relevant complication as well as differing interventional strategies for continuing an EVT in the presence of a large-vessel vasospasm., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

The glycoprotein IIb/IIIa antagonist tirofiban has been shown to prevent thromboembolic events during endovascular procedures, but the benefits and risks of its prophylactic early intraprocedural administration for stand-alone coil embolization of acutely ruptured aneurysms are still unclear. We conducted a retrospective single-center analysis of patients treated for aneurysmal subarachnoid hemorrhage with stand-alone coil embolization. Two study cohorts were compared according to the primary prophylactic antithrombotic medication during the procedure: patients receiving only intravenous heparin (HEP) versus patients receiving tirofiban in addition to heparin prior to final aneurysm obliteration (HEP + TF). Outcome endpoints were the incidence of angiographically visible thrombus formation or distal embolization, and the incidence of periprocedural intracranial hemorrhage (ICH). Of 204 cases, 159 were prophylactically treated with HEP and 45 with HEP + TF. Intraprocedural thromboembolic events were less frequent with HEP + TF before and after propensity score matching (PSM) (2.5% vs. 19.7%, p = 0.017). The incidence of ICH and symptomatic ICH did not differ between HEP + TF and HEP before and after PSM (20.5% vs. 30.7%, p = 0.29; and 5.1% vs. 4%, p = 0.88). Early intraprocedural tirofiban administration may be effective in preventing thromboembolic complications during stand-alone coil embolization of acutely ruptured aneurysms without increasing the risk of ICH., (© 2024. The Author(s).)

Background: The superiority of endovascular thrombectomy (EVT) over medical management was not established in two early basilar artery occlusion (BAO) randomized controlled trials. Despite this, many clinicians recommended EVT for acute BAO under certain circumstances. This paper aims to compare physicians' diagnostic and management strategies of BAO according to gender., Methods: From January to March 2022 an international survey was conducted regarding management strategies in acute BAO. We compared responses between clinicians by identifying gender. Questions were designed to examine clinical and imaging parameters influencing management of patients with BAO., Results: Among the 1245 respondents from 73 countries, 311 (25.0%) identified as female. This figure was 13.6% amongst interventionists. Geographically, female respondents were lowest in Asia (14.5%) and North America (23.9%). The proportion of respondents identifying as female was consistent regardless of their years of experience. Female respondents were more likely to choose time of onset as time of first estimated stroke like symptom (48.0% vs. 38.5%, p  < .01), were less likely to favor thrombectomy in the V4 segment of vertebrobasilar artery occlusions (31.5% vs. 43.3%, p  < .01), and were less likely to find it acceptable to enroll all patients who met trial criteria in the standard medical treatment arm of a clinical trial (41.2% vs. 47.0%, p  = .01). Male respondents were more likely to agree that thrombolysis would not alter their decision on proceeding with EVT (93.7% vs. 88.3%, p  < .01)., Conclusions: Female clinicians appear to be significantly underrepresented in stroke medicine. This is most pronounced amongst interventionists and in Asia. Although male and female opinions were closely aligned on many aspects of BAO management, differences in opinion were observed in a number of significant areas which influence decision making.

Background The combination of intravenous thrombolysis (IVT) with mechanical thrombectomy (MT) may have clinical benefits for patients with medium vessel occlusion. Purpose To examine whether MT combined with IVT is associated with different outcomes than MT alone in patients with acute ischemic stroke (AIS) and medium vessel occlusion. Materials and Methods This retrospective study included consecutive adult patients with AIS and medium vessel occlusion treated with MT or MT with IVT at 37 academic centers in North America, Asia, and Europe. Data were collected from September 2017 to July 2021. Propensity score matching was performed to reduce confounding. Univariable and multivariable logistic regression analyses were performed to test the association between the addition of IVT treatment and different functional and safety outcomes. Results After propensity score matching, 670 patients (median age, 75 years [IQR, 64-82 years]; 356 female) were included in the analysis; 335 underwent MT alone and 335 underwent MT with IVT. Median onset to puncture (350 vs 210 minutes, P < .001) and onset to recanalization (397 vs 273 minutes, P < .001) times were higher in the MT group than the MT with IVT group, respectively. In the univariable regression analysis, the addition of IVT was associated with higher odds of a modified Rankin Scale (mRS) score 0-2 (odds ratio [OR], 1.44; 95% CI: 1.06, 1.96; P = .019); however, this association was not observed in the multivariable analysis (OR, 1.37; 95% CI: 0.99, 1.89; P = .054). In the multivariable analysis, the addition of IVT also showed no evidence of an association with the odds of first-pass effect (OR, 1.27; 95% CI: 0.9, 1.79; P = .17), Thrombolysis in Cerebral Infarction grades 2b-3 (OR, 1.64; 95% CI: 0.99, 2.73; P = .055), mRS scores 0-1 (OR, 1.27; 95% CI: 0.91, 1.76; P = .16), mortality (OR, 0.78; 95% CI: 0.49, 1.24; P = .29), or intracranial hemorrhage (OR, 1.25; 95% CI: 0.88, 1.76; P = .21). Conclusion Adjunctive IVT may not provide benefit to MT in patients with AIS caused by distal and medium vessel occlusion. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Wojak in this issue.

Background: Acute ischemic stroke with isolated posterior cerebral artery occlusion (iPCAO) lacks management evidence from randomized trials. We aimed to evaluate whether the association between endovascular treatment (EVT) and outcomes in iPCAO acute ischemic stroke is modified by initial stroke severity (baseline National Institutes of Health Stroke Scale [NIHSS]) and arterial occlusion site., Methods: Based on the multicenter, retrospective, case-control study of consecutive iPCAO acute ischemic stroke patients (PLATO study [Posterior Cerebral Artery Occlusion Stroke]), we assessed the heterogeneity of EVT outcomes compared with medical management (MM) for iPCAO, according to baseline NIHSS score (≤6 versus >6) and occlusion site (P1 versus P2), using multivariable regression modeling with interaction terms. The primary outcome was the favorable shift of 3-month modified Rankin Scale (mRS). Secondary outcomes included excellent outcome (mRS score 0-1), functional independence (mRS score 0-2), symptomatic intracranial hemorrhage, and mortality., Results: From 1344 patients assessed for eligibility, 1059 were included (median age, 74 years; 43.7% women; 41.3% had intravenous thrombolysis): 364 receiving EVT and 695 receiving MM. Baseline stroke severity did not modify the association of EVT with 3-month mRS distribution ( P interaction =0.312) but did with functional independence ( P interaction =0.010), with a similar trend on excellent outcome ( P interaction =0.069). EVT was associated with more favorable outcomes than MM in patients with baseline NIHSS score >6 (mRS score 0-1, 30.6% versus 17.7%; adjusted odds ratio [aOR], 2.01 [95% CI, 1.22-3.31]; mRS score 0 to 2, 46.1% versus 31.9%; aOR, 1.64 [95% CI, 1.08-2.51]) but not in those with NIHSS score ≤6 (mRS score 0-1, 43.8% versus 46.3%; aOR, 0.90 [95% CI, 0.49-1.64]; mRS score 0-2, 65.3% versus 74.3%; aOR, 0.55 [95% CI, 0.30-1.0]). EVT was associated with more symptomatic intracranial hemorrhage regardless of baseline NIHSS score ( P interaction =0.467), while the mortality increase was more pronounced in patients with NIHSS score ≤6 ( P interaction =0.044; NIHSS score ≤6: aOR, 7.95 [95% CI, 3.11-20.28]; NIHSS score >6: aOR, 1.98 [95% CI, 1.08-3.65]). Arterial occlusion site did not modify the association of EVT with outcomes compared with MM., Conclusions: Baseline clinical stroke severity, rather than the occlusion site, may be an important modifier of the association between EVT and outcomes in iPCAO. Only severely affected patients with iPCAO (NIHSS score >6) had more favorable disability outcomes with EVT than MM, despite increased mortality and symptomatic intracranial hemorrhage., Competing Interests: Disclosures Dr Dabus: consultancy for Cerenovus, Penumbra, Route 92, Medtronic, MicroVention, and Stryker; stock holdings in RIST and InNeuroCo. Dr Fifi: consultancy for Cerenovus, MicroVention, and Stryker; Data Safety Monitoring Board (DSMB) for MIVI; stock holdings in Imperative Care and Sim&Cure. Dr Fischer: research support from the Swiss National Science Foundation (SNF), Medtronic, Stryker, Rapid Medical, Penumbra, and Phenox; consultancies for Stryker and CSL Behring; is on the advisory board for Alexion/Portola, Boehringer Ingelheim, Biogen, and Acthera. Dr Haussen: consultancy for Vesalio, Cerenovus, Stryker, Brainomix, Poseydon Medical, and Chiesi USA; DSMB for Jacobs Institute; stock options in viz AI. Dr Herweh: consultancy for Brainomix; speaker with Stryker. Dr Jadhav: consulting with Basking Biosciences; stock options in Gravity Medical Technology; a patent for a novel stent retriever device licensed to Basking Biosciences; and Editor-in-Chief for the Stroke: Vascular and Interventional Neurology journal. Dr Kaesmacher: grants from the Swiss Academy of Medical Sciences/Bangerter Foundation, Swiss Stroke Society, and Clinical Trials Unit Bern. Dr Kaiser: grants from the Joachim Herz Foundation. Dr Kuramatsu: grants from Alexion Pharmaceuticals, Bayer Healthcare, Sanofi Pasteur, and Biogen Idec. Dr Marto: consulting and speaker fees from Amicus Therapeutics and Boehringer Ingelheim. Dr Michel: grants from the University of Lausanne and SNF. Dr Möhlenbruch: grants from Medtronic, Stryker, and MicroVention. Dr Mokin: stock holdings in BrainQ, Serenity Medical, Synchron, and Bendit Technology; consulting at MicroVention, Medtronic, and Johnson & Johnson. Dr Nagel: consultancy for Brainomix; speaker at Boehringer Ingelheim and Pfizer. Dr Nguyen: Associate Editor of Stroke, advisory board at Aruna Bio and Brainomix. Dr Nogueira: consultancy for Biogen, Brainomix, Corindus, Cerenovus, Stryker, Medtronic, Ceretrieve, Anaconda Biomed, Vesalio, Imperative Care, NeuroVasc Technologies, viz AI, Genentech, Prolong Pharmaceuticals, Perfuze, Phenox, and RapidPulse; stock options in viz AI, Vesalio, Perfuze, Corindus, Brainomix, and Ceretrieve; grants from Cerenovus and Stryker. Dr Nolte: research support and compensation from Novartis, AstraZeneca, Deutsches Zentrum für Herz-Kreislaufforschung, and Deutsches Zentrum für Neurodegenerative Erkrankungen; consultancy for Alexion, Daiichi Sankyo, Novartis, AstraZeneca, Bayer Healthcare, Pfizer, Alexion, and Bristol Myers Squibb. S. Poli: research grants from BMS/Pfizer, Boehringer Ingelheim, Daiichi Sankyo, German Federal Joint Committee Innovation Fund, and German Federal Ministry of Education and Research, Helena Laboratories and Werfen as well as speakers’ honoraria/consulting fees from Alexion, AstraZeneca, Bayer, Boehringer Ingelheim, Bristol Myers Squibb/Pfizer, Daiichi Sankyo, Portola, and Werfen (all outside of the submitted work). Dr Psychogios: grants from Penumbra, Rapid Medical, Medtronic, Phenox, Bangerter-Rhyner Stiftung, SNF, Siemens Healthineers, and Stryker Neurovascular; travel support from Medtronic, Siemens Healthineers, Phenox, Penumbra, and Stryker; consultancy for Siemens Healthineers. Dr Puetz: lecturer for Daiichi Sankyo. Dr Ribo: consultancy for Medtronic MiniMed, Cerenovus, AptaTargets, Stryker, and Philips; stock holdings in Methinks, Nora, and Anaconda Biomed. Dr Ringleb: travel support from Bayer and Bristol Myers Squibb; consultancy for Daiichi Sankyo Company and Boehringer Ingelheim. Dr Romoli: research grants from the Italian Stroke Association; consultancy for CSL Behring. Dr Sheth: consultancy for Imperative Care, viz AI, and Penumbra; compensation from Motif Neurosciences (other services); grants from the National Institutes of Health. Dr Siddiqui: ownership stake in Integra Lifesciences and Medtronic; consultancy for Cordis, Rapid Medical, MicroVention, Medtronic Vascular, Vassol, IRRAS USA, Boston Scientific, Amnis Therapeutics, Minnetronix Neuro, Canon Medical Systems USA, Cardinal Health 200, Johnson & Johnson–Latin America, Corindus, Penumbra, Apellis Pharmaceuticals, W.L. Gore & Associates, Stryker Corporation, and viz AI; stock holdings in E8, Spinnaker Medical, Endostream Medical, Cerebrotech Medical Systems, Adona Medical, Bend IT Technologies, Whisper Medical, Neurotechnology Investors, Collavidence, Instylla, Q’Appel Medical, Serenity Medical, Borvo Medical, NeuroRadial Technologies, Sense Diagnostics, Tulavi Therapeutics, Synchron, Neurolutions, Viseon, BlinkTBI, Radical Catheter Technologies, and Truvic Medical; stock options in viz AI, StimMed, Three Rivers Medical, Silk Road Medical, Imperative Care, CVAid Ltd, Cerevatech Medical, InspireMD, PerFlow Medical; security holdings in Vastrax, Launch NY, QAS.ai, VICIS, Inc, Neurovascular Diagnostics, Cognition Medical, and SongBird Therapy. Dr Strbian: Assistant Editor of Stroke, Editorial Board of European Stroke Journal, advisory board at Boehringer Ingelheim, Alexion/AstraZeneca, and Bristol Myers Squibb/Janssen; research support from Boehringer Ingelheim; consultancies for Orion, Herantis Pharma, and CSL Behring. The other authors report no conflicts.

Background: Numerous questions regarding procedural details of distal stroke thrombectomy remain unanswered. This study assesses the effect of anesthetic strategies on procedural, clinical and safety outcomes following thrombectomy for distal medium vessel occlusions (DMVOs)., Methods: Patients with isolated DMVO stroke from the TOPMOST registry were analyzed with regard to anesthetic strategies (ie, conscious sedation (CS), local (LA) or general anesthesia (GA)). Occlusions were in the P2/P3 or A2-A4 segments of the posterior and anterior cerebral arteries (PCA and ACA), respectively. The primary endpoint was the rate of complete reperfusion (modified Thrombolysis in Cerebral Infarction score 3) and the secondary endpoint was the rate of modified Rankin Scale score 0-1. Safety endpoints were the occurrence of symptomatic intracranial hemorrhage and mortality., Results: Overall, 233 patients were included. The median age was 75 years (range 64-82), 50.6% (n=118) were female, and the baseline National Institutes of Health Stroke Scale score was 8 (IQR 4-12). DMVOs were in the PCA in 59.7% (n=139) and in the ACA in 40.3% (n=94). Thrombectomy was performed under LA±CS (51.1%, n=119) and GA (48.9%, n=114). Complete reperfusion was reached in 73.9% (n=88) and 71.9% (n=82) in the LA±CS and GA groups, respectively (P=0.729). In subgroup analysis, thrombectomy for ACA DMVO favored GA over LA±CS (aOR 3.07, 95% CI 1.24 to 7.57, P=0.015). Rates of secondary and safety outcomes were similar in the LA±CS and GA groups., Conclusion: LA±CS compared with GA resulted in similar reperfusion rates after thrombectomy for DMVO stroke of the ACA and PCA. GA may facilitate achieving complete reperfusion in DMVO stroke of the ACA. Safety and functional long-term outcomes were comparable in both groups., Competing Interests: Competing interests: JF: Consulting fees from Cerenovus, Medtronic, Phenox, Penumbra, Roche, Tonbridge; participation on a Data Safety Monitoring Board of Stryker and Phenox; stock holdings for Tegus and Vastrax, Associate Editor for JNIS. RC: Consultant and/or proctor for BALT, Stryker, Microvention, Rapid Medical, Siemens Medical Systems. MM: Institutional grants: Balt, Medtronic, MicroVention, Stryker. AG: Proctor/consultant/speaker for Medtronic, Stryker and Penumbra. MM-G: Consultant for Medtronic, Stryker and Balt, Associate Editor for JNIS. FD: Grant from Cerenovus/ Johnson&Johnson, consulting fees from Cerus Endovascular, Balt, Cerenovus/Johnson&Johnson, honoraria for lectures Asahi, Cerenovus/Johnson&Johnson, Acandis, Stryker, Advisory Board Cerenovus Johnson&Johsno, Associate Editor for JNIS. JK: Grants from SAMW/Bangerter, grants from Swiss Stroke Society, and grants from Clinical Trial Unit Bern outside the submitted work. LLLY: Consultant for Stryker, SeeMode, and See-mode, Cerenovus honoraria, Jakarta Neuroupdate honorarium, Research Support from National Medical research Council (NMRC) Singapore and Ministry of Health (MOH). Stock holdings for Cereflo, SNVIS vice president. BT: Grants from ExxonMobil-NUS Research Fellowship for Clinicians. PN: Consultant/Proctor for Balt, Cerenovus, Medtronic, Penumbra, Stryker. AG: Honoraria for lectures from Stryker Neurovascular, Medtronic, Penumbra. BG: grants from the French Ministry of Health and is the primary investigator of the TITAN, DIRECT ANGIO, and IA-RESCUE trial; consulting fees from Air Liquide, MIVI, Medtronic, Microvention, and Penumbra. LM: Compensation as a speaker for Balt Prime. GB: Compensation as a speaker for Balt Prime., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Background and Aims: Octogenarians are underrepresented in recently published studies that showed the benefit of endovascular stroke treatment (EST) for patients with acute basilar artery occlusion (BAO). We aimed to compare the clinical outcome of octogenarians with BAO and EST compared to younger patients (YPs) and identify independent outcome predictors., Methods: This is a retrospective, single-center analysis of patients treated for BAO with EST from January 2013 until June 2021 in a tertiary stroke center. Octogenarians (80-89 years) were compared to YPs. A study endpoint was a favorable clinical outcome as per the modified Rankin Scale (mRS 0-3), 90 days after stroke onset. The study groups were compared using univariate analysis, and a multivariable logistic regression analysis was performed to define independent predictors for favorable and unfavorable (mRS 5-6) clinical outcomes., Results: In this study cohort, 74/191 (38.7%) octogenarians had a higher pre-stroke mRS [median, interquartile range (IQR): 2, 1-3 octogenarians vs. 0, 0-1 YP, p < 0.001] and a comparable National Institutes of Health Stroke Scale (NIHSS) before EST (median, IQR: 21, 10-38 vs. 20, 8-35 in YP, p = 0.487). They showed a comparable rate of favorable outcome (mRS 0-3, 90 days, 23.0 vs. 25.6% in YP, p = 0.725), but were less often functionally independent (mRS 0-2: 10.8% in octogenarians vs. 23.0% in YP, p = 0.049). The rate of unfavorable clinical outcome was comparable (mRS 5-6, n = 40, 54.1% in octogenarians vs. n = 64, 54.7% in YP, p = 0.831). A baseline NIHSS was an independent predictor for clinical outcome in YPs [e.g., for unfavorable clinical outcome: odds ratio (OR) 1.061, confidence interval (CI) 1.027-1.098, p = 0.005] and for favorable clinical outcome in octogenarians. Pre-stroke mRS predicted favorable outcomes in octogenarians (OR 0.54, CI 0.30-0.90, p = 0.0291), while age predicted unfavorable outcomes in YPs (OR 1.045, CI 1.011-1.086, p = 0.0137)., Conclusion: Octogenarians with acute BAO eligible for EST are as likely to achieve a favorable outcome as YPs, and the rate of death or severe disability is comparable. The admission NIHSS is an independent predictor for favorable and unfavorable outcomes in YP and for favorable outcomes in octogenarians. In this study cohort, pre-stroke mRS predicted favorable outcomes in octogenarians while age predicted an unfavorable outcome in YPs., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Weyland, Mutke, Zimmermann-Miotk, Schmitt, Chen, Schönenberger, Möhlenbruch, Bendszus and Jesser.)

Background and Purpose: Vasospasm is a common complication of endovascular therapy (EVT). There is a lack of understanding of risk factors for periprocedural vasospasm. Here, we aimed to identify factors associated with vasospasm in patients with acute ischemic stroke who undergo EVT., Methods: We conducted a retrospective single-center analysis of patients receiving EVT for anterior circulation vessel occlusion between January 2015 and December 2021. Patients were excluded if they showed signs of intracranial atherosclerotic disease (ICAD) or if they underwent intra-arterial thrombolysis. Study groups were defined as patients developing vasospasm during EVT (V+) and patients who did not (V-). The study groups were compared in univariable analysis. Multivariable regression models were developed to predict the patient's risk for developing vasospasm based on pre-identified potential prognostic factors. The secondary endpoint was clinical outcome defined as the modified Rankin Scale (mRS) difference between pre-stroke mRS and discharge mRS (delta mRS) and likelihood of successful reperfusion (TICI 2b/3)., Results: In total, 132/1768 patients (7.5%) developed vasospasm during EVT. Vasospasm was more likely to occur in EVT with multiple thrombectomy attempts and after several stent retriever maneuvers. Factors associated with developing vasospasm were younger age (OR = 0.967, 95% CI = 0.96-0.98) and lower pre-stroke mRS (OR = 0.759, 95% CI = 0.63-0.91). The prediction model incorporating patient age, pre-stroke mRS, stent retriever thrombectomy attempts, and total attempts as prognostic factors was found to predict vasospasm with good accuracy (AUC = 0.714, 95% CI = 0.709-0.720). V+ patients showed higher median (IQR) delta mRS (2 (1-4) vs 2 (1-3); p  = 0.014). There was no difference in successful reperfusion (TICI 2b-3) between those with or without vasospasm., Conclusion: Vasospasm was a common complication in EVT affecting younger and previously healthy patients. Presence of vasospasm did not reduce the likelihood of successful reperfusion. As independent predictors, patient age, pre-stroke mRS, thrombectomy maneuvers, and stent retriever attempts predict the occurrence of vasospasm during EVT with good accuracy.

Background: Radiological neuro-interventions, especially endovascular stroke treatment (EST), are increasing in case numbers worldwide with increasing occupational radiation exposure. Aim of this study was to define the radiation exposure of neurointerventionalists (NI) during EST and to compare the accumulated dose reaching the left arm with the left temple., Methods: This is a prospective observational study in a tertiary stroke center conducted between 11/2021 and 07/2022. Radiation exposure was measured using real time dosimetry with dosimeters being carried by the NI during EST simultaneously at the left temple and left arm. The effective dose [µSV] per dose area product (DAP) and potential influencing factors were compared in univariate analysis between the two dosimeter positions., Results: In total, 82 ESTs were analyzed with a median DAP of 6179 µGy*m 2 (IQR 3271 µGy*m 2 -11720 µGy*m 2 ). The accumulated dose at the left arm and left temple correlated with the DAP and fluoroscopy time of the EST (DAP and arm: p = 0.01, DAP and temple: p = 0.006). The radiation exposure (RE) showed a wide range and did not differ between the two dosimeter positions (median, IQR arm 7 µSV, IQR 3.1-16.9 µSV, min. 0.3 µSV max. 64.5 µSV) vs. head 7 µSv, IQR 3.2-17.4 µSV, min. 0.38 µSV, max. 48.6 µSV, p = 0.94). Occupational RE depends on the number of thrombectomy attempts, but not the target vessel occlusion location or the NI's body height., Conclusion: Neurointerventionalists experience a generally low but very variable radiation exposure during EST, which depends on the intervention's fluoroscopy time and dose area product as well as thrombectomy attempts but does not differ between left temple and left arm., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Background: Endovascular embolization using liquid embolic agents (LEAs) is frequently applied for the treatment of intracranial vascular malformations. Appropriate visibility of LEAs during embolization is essential for visual control and to prevent complications. Since LEAs contain different radiopaque components of varying concentrations, our aim was the systematic assessment of the visibility of the most used LEAs in fluoroscopy., Methods: A specifically designed in vitro model, resembling cerebral vessels, was embolized with Onyx 18, Squid 18, Squid 12, PHIL (precipitating hydrophobic injectable liquid) 25%, PHIL LV (low viscosity) and NBCA (n-butyl cyanoacrylate) mixed with iodized oil (n=3 for each LEA), as well as with contrast medium and saline, both serving as a reference. Fluoroscopic image acquisition was performed in accordance with clinical routine settings. Visibility was graded quantitatively (contrast to noise ratio, CNR) and qualitatively (five-point scale)., Results: Overall, all LEAs provided at least acceptable visibility in this in vitro model. Onyx and Squid as well as NBCA mixed with iodized oil were best visible at a comparable level and superior to the formulations of PHIL, which did not differ in quantitative and qualitative analyses (eg, Onyx 18 vs PHIL 25% along the 2.0 mm sector: mean CNR±SD: 3.02±0.42 vs 1.92±0.35; mean score±SD: 5.00±0.00 vs 3.75±0.45; p≤0.001, respectively)., Conclusion: In this systematic in vitro study, relevant differences in the fluoroscopic visibility of LEAs in neurointerventional embolization procedures were demonstrated, while all investigated LEAs provided acceptable visibility in our in vitro model., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Introduction: Endovascular stroke treatment (EST) is commonly performed for acute basilar artery occlusion (BAO). We aimed to identify the role of the exact location of BAO in patients receiving EST regarding the stroke etiology, recanalization success and prediction of favorable clinical outcome., Methods: Retrospective analysis of 191 consecutive patients treated for BAO with EST from 01/2013 until 06/2021 in a tertiary stroke center. Groups were defined according to exact location of BAO in I: proximal third, II: middle third, III: distal third and IV: tip of the basilar artery. Univariate and multivariate analyses were performed for BAO location comparing stroke etiology, recanalization result and favorable clinical outcome according to mRS 0-3 90 days after stroke onset., Results: Occlusion sides types I-IV were evenly distributed (37, 36, 60 and 58 patients). Types I and II were more often associated with large artery atherosclerosis (50 vs. 10 patients, p < 0.001). Distal/tip occlusion (types III/IV) occurred mostly in cardiac embolism or embolic stroke of unknown source (89 vs. 12 in types I/II, p < 0.001). Occlusion site correlated with the underlying stroke etiology (AUC [Area under the curve] 0.89, p < 0.0001, OR [odds ratio] for embolism in type IV: 245). Recanalization rates were higher in patients with distal occlusions (type III/IV OR 3.76, CI [95% confidence interval] 1.51-9.53, p = 0.0076). The BAO site is not predicting favorable clinical outcome., Conclusion: The exact basilar artery occlusion site in patients eligible for endovascular stroke treatment reflects the stroke etiology and is associated with differing recanalization success but does not predict favorable clinical outcome., (© 2022. The Author(s).)

In this review article, we aim to provide a summary of the discoveries and developments that were instrumental in the evolution of the Neurointerventional field. We begin with developments in the advent of Diagnostic Cerebral Angiography and progress to cerebral aneurysm treatment, embolization in AVMs and ischemic stroke treatment. In the process we discuss many persons who were key in the development and maturation of the field. A pivotal aspect to rapid growth in the field has been the multidisciplinary involvement of the different neuroscience specialties and therefore we close out our discussion with excitement about ongoing and future developments in the field with a focus on treatments in the non-cerebrovascular disease realm., Competing Interests: None declared., (Thieme. All rights reserved.)

Background Evidence supporting a potential benefit of thrombectomy for distal medium vessel occlusions (DMVOs) of the anterior cerebral artery (ACA) is, to the knowledge of the authors, unknown. Purpose To compare the clinical and safety outcomes between mechanical thrombectomy (MT) and best medical treatment (BMT) with or without intravenous thrombolysis for primary isolated ACA DMVOs. Materials and Methods Treatment for Primary Medium Vessel Occlusion Stroke, or TOPMOST, is an international, retrospective, multicenter, observational registry of patients treated for DMVO in daily practice. Patients treated with thrombectomy or BMT alone for primary ACA DMVO distal to the A1 segment between January 2013 and October 2021 were analyzed and compared by one-to-one propensity score matching (PSM). Early outcome was measured by the median improvement of National Institutes of Health Stroke Scale (NIHSS) scores at 24 hours. Favorable functional outcome was defined as modified Rankin scale scores of 0-2 at 90 days. Safety was assessed by the occurrence of symptomatic intracerebral hemorrhage and mortality. Results Of 154 patients (median age, 77 years; quartile 1 [Q1] to quartile 3 [Q3], 66-84 years; 80 men; 94 patients with MT; 60 patients with BMT) who met the inclusion criteria, 110 patients (median age, 76 years; Q1-Q3, 67-83 years; 50 men; 55 patients with MT; 55 patients with BMT) were matched. DMVOs were in A2 (82 patients; 53%), A3 (69 patients; 45%), and A3 (three patients; 2%). After PSM, the median 24-hour NIHSS point decrease was -2 (Q1-Q3, -4 to 0) in the thrombectomy and -1 (Q1-Q3, -4 to 1.25) in the BMT cohort ( P = .52). Favorable functional outcome (MT vs BMT, 18 of 37 [49%] vs 19 of 39 [49%], respectively; P = .99) and mortality (MT vs BMT, eight of 37 [22%] vs 12 of 39 [31%], respectively; P = .36) were similar in both groups. Symptomatic intracranial hemorrhage occurred in three (2%) of 154 patients. Conclusion Thrombectomy appears to be a safe and technically feasible treatment option for primary isolated anterior cerebral artery occlusions in the A2 and A3 segment with clinical outcomes similar to best medical treatment with and without intravenous thrombolysis. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Zhu and Wang in this issue.

Purpose: Unfavorable vascular anatomy can impede thrombectomy in patients with acute ischemic stroke. The aim of this study was to determine the prevalence of aortic arch types, aortic arch branching patterns and supra-aortic arterial tortuosity in stroke patients with large vessel occlusion., Methods: Computed tomography (CT) and magnetic resonance (MR) images of all stroke patients in an institutional thrombectomy registry were retrospectively reviewed. Aortic arch types and branching patterns of all patients were determined. In patients with anterior circulation stroke, the prevalence of tortuosity (elongation, kinking or coiling) of the supra-aortic arteries of the affected side was additionally assessed., Results: A total of 1705 aortic arches were evaluated. Frequency of aortic arch types I, II and III were 777 (45.6%), 585 (34.3%) and 340 (19.9%), respectively. In 1232 cases (72.3%), there was a normal branching pattern of the aortic arch. The brachiocephalic trunk and the left common carotid artery had a common origin in 258 cases (15.1%). In 209 cases (12.3%), the left common carotid artery arose from the brachiocephalic trunk. Of 1598 analyzed brachiocephalic trunks and/or common carotid arteries, 844 (52.8%) had no vessel tortuosity, 592 (37.0%) had elongation, 155 (9.7%) had kinking, and 7 (0.4%) had coiling. Of 1311 analyzed internal carotid arteries, 471 (35.9%) had no vessel tortuosity, 589 (44.9%) had elongation, 150 (11.4%) had kinking, and 101 (7.7%) had coiling., Conclusion: With 20%, type III aortic arches are found in a relevant proportion of stroke patients eligible for mechanical thrombectomy. Nearly half of the stroke patients present with supra-aortic arterial tortuosity, mostly arterial elongation., (© 2022. The Author(s).)

Purpose: The treatment of vasospasms during endovascular stroke treatment (EST) with intra-arterial nimodipine (NM) is routinely performed. However, the efficacy of resolving iatrogenic vasospasms during the angiographic intervention and the infarct development in follow-up imaging after EST has not been studied yet., Methods: Retrospective single-center analysis of patients receiving EST for anterior circulation vessel occlusion between 01/2015 and 12/2021. The primary endpoint was ASPECTS in follow-up imaging. Secondary endpoints were the clinical outcome (combined endpoint NIHSS 24 h after EST and difference between modified Rankin Scale (mRS) before stroke and at discharge (delta mRS)) and intracranial hemorrhage (ICH) in follow-up imaging. Patients with vasospasms receiving NM (NM+) or not (NM-) were compared in univariate analysis., Results: Vasospasms occurred in 79/1283 patients (6.2%), who consecutively received intra-arterial NM during EST. The targeted vasospasm angiographically resolved in 84% (66/79) under NM therapy. ASPECTS was lower in follow-up imaging after vasospasms and NM-treatment (NM - 7 (6-9), NM + 6 (4.5-8), p = 0.013) and the clinical outcome was worse (NIHSS 24 h after EST was higher in patients treated with NM (median, IQR; NM+: 14, 5-21 vs. NM-: 9, 3-18; p = 0.004), delta-mRS was higher in the NM + group (median, IQR; NM+: 3, 1-4 vs. NM-: 2, 1-2; p = 0.011)). Any ICH (NM+: 27/79, 34.2% vs. NM-: 356/1204, 29.6%; p = 0.386) and symptomatic ICH (NM+: 2/79, 2.5% vs. NM-: 21/1204, 1.7%; p = 0.609) was equally distributed between groups., Conclusion: Intra-arterial nimodipine during EST resolves iatrogenic vasospasms efficiently during EST without increasing intracranial hemorrhage rates. However, patients with vasospasms and NM treatment show higher infarct growth resulting in lower ASPECTS in follow-up imaging., (© 2023. The Author(s).)

Endovascular therapy (EVT) has revolutionized the treatment of acute ischemic stroke. In the past few years, endovascular treatment indications have expanded to include patients being treated in the extended window, with large ischemic core infarction, basilar artery occlusion (BAO) thrombectomy, as demonstrated by several randomized clinical trials. Intravenous thrombolysis (IVT) bridging to mechanical thrombectomy has also been studied via several randomized clinical trials, with the overall results indicating that IVT should not be skipped in patients who are candidates for both IVT and EVT. Simplification of neuroimaging protocols in the extended window to permit non-contrast CT, CTA collaterals have also expanded access to mechanical thrombectomy, particularly in regions across the world where access to advanced imaging may not be available. Ongoing study of areas to develop include rescue stenting in patients with failed thrombectomy, medium vessel occlusion thrombectomy, and carotid tandem occlusions. In this narrative review, we summarize recent trials and key data in the treatment of patients with large ischemic core infarct, simplification of neuroimaging protocols for the treatment of patients presenting in the late window, bridging thrombolysis, and BAO EVT evidence. We also summarize areas of ongoing study including medium and distal vessel occlusion., Competing Interests: Dr. Thanh Nguyen reports advisory board of Idorsia. All the other authors report no other conflict of interest., (©2023 The Japanese Society for Neuroendovascular Therapy.)

Background and Purpose: Prediction of futile recanalization (FR), i.e. failure of long-term functional independence despite full reperfusion in mechanical thrombectomy (MT), is instrumental in patients undergoing endovascular therapy., Methods: Retrospective single-center analysis of patients treated for anterior circulation LVO ensuing successful MT (mTICI 2c-3) between January 2014 and April 2019. FR was defined as modified Rankin Scale (mRS) 90 days after stroke onset > 2 or mRS > pre-stroke mRS. Multivariable analysis was performed with variables available before treatment initiation regarding their association with FR. Performance of the regression model was then compared with a model including parameters available after MT., Results: Successful MT was experienced by 549/1146 patients in total. FR occurred in 262/549 (47.7%) patients. Independent predictors of FR were male sex, odds ratio (OR) with 95% confidence interval (CI) 1.98 (1.31-3.05, p 0.001), age (OR 1.05, CI 1.03-1.07, p < 0.001), NIHSS on admission (OR 1.10, CI 1.06-1.13, p < 0.001), pre-stroke mRS (OR 1.22, CI 1.03-1.46, p 0.025), neutrophile-lymphocyte ratio (OR 1.03, CI 1.00-1.06, p 0.022), baseline ASPECTS (OR 0.77, CI 0.68-0.88, p < 0.001), and absence of bridging i.v. lysis (OR 1.62, 1.09-2.42, p 0.016). The prediction model's Area Under the Curve was 0.78 (CI 0.74-0.82) and increased with parameters available after MT to 0.86 (CI 0.83-0.89) with failure of early neurological improvement being the most important predictor of FR (OR 15.0, CI 7.2-33.8)., Conclusion: A variety of preinterventional factors may predict FR with substantial certainty, but the prediction model can still be improved by considering parameters only available after MT, in particular early neurological improvement., (© 2022. The Author(s).)

For advanced territorial ischemia numerous retrospective and prospective studies have shown a positive effect of mechanical thrombectomy (MT) compared to best medicinal treatment alone. For patients with minor stroke (NIHSS < 6) there is currently a lack of evidence for MT. Appropriate study protocols must differentiate between patients with large vessel occlusion with disproportionately mild symptoms and more distal vascular occlusion and therefore correspondingly fewer clinical symptoms. The role of intravenous lysis treatment before MT as bridging lysis also currently retains its general recommendation, as large studies could not show a uniform noninferiority of MT alone. In addition, the use of intra-arterial lysis after successful MT offers a promising approach, which still needs to be evaluated. Novel aspiration catheters and stent-retrievers as well as competing thrombectomy techniques can be compared by the first pass effect, the successful recanalization with only one attempt at thrombectomy. Contact aspiration and stent-retriever thrombectomy under aspiration are equivalent and established thrombectomy procedures. For the latter, several detailed maneuver tactics are described for improvement of thrombectomy success. Also, in retrospective studies the combination with a balloon-guided catheter promises a further improvement of recanalization results. In the case of failure of supra-aortic vessel probing with inguinal access, radial access and direct carotid puncture are alternative access routes. Recent studies on ICA stenting with tandem occlusions showed a benefit of stents without an increased risk for symptomatic intracranial hemorrhage. The retrograde approach, to first treat the intracranial vessel occlusion and then the carotid stenosis, seems to be advantageous., (© 2022. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Background: A drawback of Onyx, one of the most used embolic agents for endovascular embolization of intracranial arteriovenous malformations (AVM), is the generation of imaging artifacts (IA) in computed tomography (CT). Since these artifacts can represent an obstacle for the detection of periprocedural bleeding, this study investigated the effect of artifact reduction by an iterative metal artifact reduction (iMAR) software in CT in a brain phantom., Methods: Two different in vitro models with two-dimensional tube and three-dimensional AVM-like configuration were filled with Onyx 18. The models were inserted into a brain imaging phantom and images with (n = 5) and without (n = 10) an experimental hemorrhage adjacent were acquired. Afterwards, the iMAR algorithm was applied for artifact reduction. The IAs of the original and the post-processed images were graded quantitatively and qualitatively. Moreover, qualitative definition of the experimental hemorrhage was investigated., Results: Comparing the IAs of the original and the post-processed CT images, quantitative and qualitative analysis showed a lower degree of IAs in the post-processed images, i.e. quantitative analysis: 2D tube model: 23.92 ± 8.02 Hounsfield units (HU; no iMAR; mean ± standard deviation) vs. 5.93 ± 0.43 HU (with iMAR; p < 0.001); qualitative analysis: 3D AVM model: 4.93 ± 0.18 vs. 3.40 ± 0.48 (p < 0.001). Furthermore, definition of the experimental hemorrhage was better in the post-processed images of both in vitro models (2D tube model: p = 0.004; 3D AVM model: p = 0.002)., Conclusion: The iMAR algorithm can significantly reduce the IAs evoked by Onyx 18 in CT. Applying iMAR could thus improve the accuracy of postprocedural CT imaging after embolization with Onyx in clinical practice., (© 2021. The Author(s).)

Background: Onyx is frequently used for endovascular embolization of intracranial arteriovenous malformations (AVMs) and dural arteriovenous fistulas (dAVFs). One drawback of using Onyx is the generation of artifacts in cone-beam CT (CBCT). These artifacts can represent an obstacle for the detection of periprocedural hemorrhage or planning of subsequent radiosurgery. This study investigates the effect of artifact reduction by the syngo DynaCT SMART Metal Artifact Reduction (MAR) software., Methods: A standardized in vitro tube model (n=10) was filled with Onyx 18 and CBCT image acquisition was conducted in a brain imaging phantom. Furthermore, post-interventional CBCT images of 20 patients with AVM (n=13) or dAVF (n=7), each treated with Onyx, were investigated. The MAR software was applied for artifact reduction. Artifacts of the original and the post-processed images were analyzed quantitatively (standard deviation in a region of interest on the layer providing the most artifacts) and qualitatively. For the patient images, the effect of the MAR software on brain parenchyma on artifact-free images was further investigated., Results: Quantitative and qualitative analyses of both datasets demonstrated a lower degree of artifacts in the post-processed images (eg, patient images: 38.30±22.03 density units (no MAR; mean SD±SD) vs 19.83±12.31 density units (with MAR; p<0.001). The MAR software had no influence on the brain parenchyma in artifact-free images., Conclusion: The MAR software significantly reduced the artifacts evoked by Onyx in CBCT without affecting the visualization of brain parenchyma on artifact-free images. Applying this software could thus improve the quality of periprocedural CBCT images after embolization with Onyx., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: The optimal endovascular strategy for reperfusing distal medium-vessel occlusions (DMVO) remains unknown. This study evaluates angiographic and clinical outcomes of thrombectomy strategies in DMVO stroke of the posterior circulation., Methods: TOPMOST (Treatment for Primary Medium Vessel Occlusion Stroke) is an international, retrospective, multicenter, observational registry of patients treated for DMVO between January 2014 and June 2020. This study analyzed endovascularly treated isolated primary DMVO of the posterior cerebral artery in the P2 and P3 segment. Technical feasibility was evaluated with the first-pass effect defined as a modified Thrombolysis in Cerebral Infarction Scale score of 3. Rates of early neurological improvement and functional modified Rankin Scale scores at 90 days were compared. Safety was assessed by the occurrence of symptomatic intracranial hemorrhage and intervention-related serious adverse events., Results: A total of 141 patients met the inclusion criteria and were treated endovascularly for primary isolated DMVO in the P2 (84.4%, 119) or P3 segment (15.6%, 22) of the posterior cerebral artery. The median age was 75 (IQR, 62-81), and 45.4% (64) were female. The initial reperfusion strategy was aspiration only in 29% (41) and stent retriever in 71% (100), both achieving similar first-pass effect rates of 53.7% (22) and 44% (44; P =0.297), respectively. There were no significant differences in early neurological improvement (aspiration: 64.7% versus stent retriever: 52.2%; P =0.933) and modified Rankin Scale rates (modified Rankin Scale score 0-1, aspiration: 60.5% versus stent retriever 68.6%; P =0.4). In multivariable logistic regression analysis, the time from groin puncture to recanalization was associated with the first-pass effect (adjusted odds ratio, 0.97 [95% CI, 0.95-0.99]; P <0.001) that in turn was associated with early neurological improvement (aOR, 3.27 [95% CI, 1.16-9.21]; P <0.025). Symptomatic intracranial hemorrhage occurred in 2.8% (4) of all cases., Conclusions: Both first-pass aspiration and stent retriever thrombectomy for primary isolated posterior circulation DMVO seem to be safe and technically feasible leading to similar favorable rates of angiographic and clinical outcome.

Background and Purpose: Information of collateral flow may help to determine eligibility for thrombectomy. Our aim was to identify CT perfusion-based surrogate parameters of good collateral status in acute anterior circulation ischemic stroke., Materials and Methods: In this retrospective study, we assessed the collateral status of 214 patients who presented with acute ischemic stroke due to occlusion of the MCA M1 segment or the carotid terminus. Collaterals were assessed on dynamic CTA images analogous to the multiphase CTA score by Menon et al. CT perfusion parameters (time-to-maximum, relative CBF, hypoperfusion intensity ratio, and CBV-index) were assessed with RAPID software. The Spearman rank correlation and receiver operating characteristic analyses were performed to identify the parameters that correlate with collateral scores and good collateral supply (defined as a collateral score of ≥4)., Results: The Spearman rank correlation was highest for a relative CBF < 38% volume (ρ = -0.66, P  < .001), followed by the hypoperfusion intensity ratio (ρ = -0.49, P  < .001), CBV-index (ρ = 0.51, P  < .001), and time-to-maximum > 8 seconds (ρ = -0.54, P  < .001). Good collateral status was better identified by a relative CBF < 38% at a lesion size <27 mL (sensitivity of 75%, specificity of 80%) compared with a hypoperfusion intensity ratio of <0.4 (sensitivity of 75%, specificity of 62%), CBV-index of >0.8 (sensitivity of 60%, specificity of 78%), and time-to-maximum > 8 seconds (sensitivity of 68%, specificity of 76%)., Conclusions: Automated CT perfusion analysis allows accurate identification of collateral status in acute ischemic stroke. A relative CBF < 38% may be a better perfusion-based indicator of good collateral supply compared with time-to-maximum, the hypoperfusion intensity ratio, and the CBV-index., (© 2022 by American Journal of Neuroradiology.)

Background: Whether to approach distal occlusions endovascularly or not in medium-sized vessels secondary to proximal large vessel occlusion stroke remains unanswered., Objective: To investigates the technical feasibility and safety of thrombectomy for secondary posterior circulation distal, medium vessel occlusions (DMVO)., Methods: TOPMOST (Treatment fOr Primary Medium vessel Occlusion STroke) is an international, retrospective, multicenter, observational registry of patients treated for distal cerebral artery occlusions. This study subanalysis endovascularly treated occlusions of the posterior cerebral artery in the P2 and P3 segment secondary preprocedural or periprocedural thrombus migration between January 2014 and June 2020. Technical feasibility was evaluated with the modified Thrombolysis in Cerebral Infarction (mTICI) scale. Procedural safety was assessed by the occurrence of symptomatic intracranial hemorrhage (sICH) and intervention-related serious adverse events., Results: Among 71 patients with secondary posterior circulation DMVO who met the inclusion criteria, occlusions were present in 80.3% (57/71) located in the P2 segment and in 19.7% (14/71) in the P3 segment. Periprocedural migration occurred in 54.9% (39/71) and preprocedural migration in 45.1% (32/71) of cases. The first reperfusion attempt led in 38% (27/71) of all cases to mTICI 3. On multivariable logistic regression analysis, increased numbers of reperfusion attempts (adjusted odds ratio (aOR)=0.39, 95% CI 0.29 to 0.88, p=0.009) and preprocedural migration (aOR=4.70, 95% CI,1.35 to 16.35, p=0.015) were significantly associated with mTICI 3. sICH occurred in 2.8% (2/71)., Conclusion: Thrombectomy for secondary posterior circulation DMVO seems to be safe and technically feasible. Even though thrombi that have migrated preprocedurally may be easier to retract, successful reperfusion can be achieved in the majority of patients with secondary DMVO of the P2 and P3 segment., Competing Interests: Competing interests: JF: research support from the German Ministry of Science and Education (BMBF), German Ministry of Economy and Innovation (BMWi), German Research Foundation (DFG), European Union (EU), Hamburgische Investitions-/Förderbank (IFB), Medtronic, Microvention, Philips, Stryker; consultancy appointments; Acandis, Bayer, Boehringer Ingelheim, Cerenovus, Covidien, Evasc Neurovascular, MD Clinicals, Medtronic, Medina, Microvention, Penumbra, Route92, Stryker, Transverse Medical; stock holdings for Tegus. PP: consultant for Penumbra and Ab Medica. AG: has served as proctor/consultant/speaker for Medtronic, Stryker, and Penumbra M. MM-G: consultant of Medtronic, Stryker, and Balt. FD: research support from Cerenovus; consultant for Cerus Endovascular, AB Medica, and Phenox; speaker honorary from Acandis, Cerenovus. JK reports grants from SAMW/Bangerter, grants from Swiss Stroke Society, and grants from Clinical Trial Unit Bern outside the submitted work. LLLY: consultant for Stryker and SeeMode; research support from National Medical Research Council (NMRC) Singapore and Ministry of Health (MOH); stock holdings for Cereflo. PBS: consultant/proctor for Balt, Acandis, Microvention. RC: consultant and/or proctor for BALT, Stryker, Microvention, Rapid Medical, Siemens Medical Systems. PN: consultant/proctor for Balt, Stryker, and Penumbra. KZ: support under the Operational Programme Integrated Infrastructure for the project: TENSION – complementary project, IMTS: 313011W875, co-financed by the European Regional Development Fund., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Objectives: Automated CT perfusion mismatch assessment is an established treatment decision tool in acute ischemic stroke. However, the reliability of this method in patients with head motion is unclear. We therefore sought to evaluate the influence of head movement on automated CT perfusion mismatch evaluation., Methods: Using a realistic CT brain-perfusion-phantom, 7 perfusion mismatch scenarios were simulated within the left middle cerebral artery territory. Real CT noise and artificial head movement were added. Thereafter, ischemic core, penumbra volumes and mismatch ratios were evaluated using an automated mismatch analysis software (RAPID, iSchemaView) and compared with ground truth simulated values., Results: While CT scanner noise alone had only a minor impact on mismatch evaluation, a tendency towards smaller infarct core estimates (mean difference of -5.3 (-14 to 3.5) mL for subtle head movement and -7.0 (-14.7 to 0.7) mL for strong head movement), larger penumbral estimates (+9.9 (-25 to 44) mL and +35 (-14 to 85) mL, respectively) and consequently larger mismatch ratios (+0.8 (-1.5 to 3.0) for subtle head movement and +1.9 (-1.3 to 5.1) for strong head movement) were noted in dependence of patient head movement., Conclusions: Motion during CT perfusion acquisition influences automated mismatch evaluation. Potentially treatment-relevant changes in mismatch classifications in dependence of head movement were observed and occurred in favor of mechanical thrombectomy., 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 and Purpose: Outcome prediction after mechanical thrombectomy (MT) in patients with acute ischemic stroke (AIS) and large vessel occlusion (LVO) is commonly performed by focusing on favorable outcome (modified Rankin Scale, mRS 0-2) after 3 months but poor outcome representing severe disability and mortality (mRS 5 and 6) might be of equal importance for clinical decision-making., Methods: We retrospectively analyzed patients with AIS and LVO undergoing MT from 2009 to 2018. Prognostic variables were grouped in baseline clinical (A), MRI-derived variables including mismatch [apparent diffusion coefficient (ADC) and time-to-maximum (Tmax) lesion volume] (B), and variables reflecting speed and extent of reperfusion (C) [modified treatment in cerebral ischemia (mTICI) score and time from onset to mTICI]. Three different scenarios were analyzed: (1) baseline clinical parameters only, (2) baseline clinical and MRI-derived parameters, and (3) all baseline clinical, imaging-derived, and reperfusion-associated parameters. For each scenario, we assessed prediction for favorable and poor outcome with seven different machine learning algorithms., Results: In 210 patients, prediction of favorable outcome was improved after including speed and extent of recanalization [highest area under the curve (AUC) 0.73] compared to using baseline clinical variables only (highest AUC 0.67). Prediction of poor outcome remained stable by using baseline clinical variables only (highest AUC 0.71) and did not improve further by additional variables. Prediction of favorable and poor outcomes was not improved by adding MR-mismatch variables. Most important baseline clinical variables for both outcomes were age, National Institutes of Health Stroke Scale, and premorbid mRS., Conclusions: Our results suggest that a prediction of poor outcome after AIS and MT could be made based on clinical baseline variables only. Speed and extent of MT did improve prediction for a favorable outcome but is not relevant for poor outcome. An MR mismatch with small ischemic core and larger penumbral tissue showed no predictive importance., Competing Interests: VM reported receiving personal fees from ai4medicine outside the submitted work. AH reported receiving personal fees from ai4medicine outside the submitted work. DF reported receiving grants from the European Commission Horizon2020 PRECISE4Q No. 777107, reported receiving personal fees from and holding an equity interest in ai4medicine outside the submitted work. There is no connection, commercial exploitation, transfer, or association between the projects of ai4medicine and the results presented in this work. SN received unrelated fees for consultancy from Brainomix and Boehringer Ingelheim, payment for lectures including service on speakers' bureaus from Pfizer, Medtronic, and Bayer AG. MB received unrelated grants from Siemens, grants and personal fees from Novartis, grants from Stryker, grants from DFG, personal fees from Merck, personal fees from Bayer, personal fees from Teva, grants and personal fees from Guerbet, personal fees from Boehringer, personal fees from Vascular Dynamics, personal fees from Grifols, and grants from the European Union, all outside the submitted work. MMö received unrelated Board Membership from Codman; consultancy from Medtronic, MicroVention, and Stryker; payment for lectures including service on speakers bureaus' from Medtronic, MicroVention, and Stryker. PR received unrelated grants for consultancy from Boehringer and lecture fees from Bayer, Boehringer Ingelheim, BMS, Daichii Sankyo, and Pfizer. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Mutke, Madai, Hilbert, Zihni, Potreck, Weyland, Möhlenbruch, Heiland, Ringleb, Nagel, Bendszus and Frey.)

Background: Hyperdense artery sign (HAS) on non-contrast CT (NCCT) can indicate a large vessel occlusion (LVO) in patients with acute ischemic stroke. HAS detection belongs to routine reporting in patients with acute stroke and can help to identify patients in whom LVO is not initially suspected. We sought to evaluate automated HAS detection by commercial software and compared its performance to that of trained physicians against a reference standard., Methods: Non-contrast CT scans from 154 patients with and without LVO proven by CT angiography (CTA) were independently rated for HAS by two blinded neuroradiologists and an AI-driven algorithm (Brainomix®). Sensitivity and specificity were analyzed for the clinicians and the software. As a secondary analysis, the clot length was automatically calculated by the software and compared with the length manually outlined on CTA images as the reference standard., Results: Among 154 patients, 84 (54.5%) had CTA-proven LVO. HAS on the correct side was detected with a sensitivity and specificity of 0.77 (CI:0.66-0.85) and 0.87 (0.77-0.94), 0.8 (0.69-0.88) and 0.97 (0.89-0.99), and 0.93 (0.84-0.97) and 0.71 (0.59-0.81) by the software and readers 1 and 2, respectively. The automated estimation of the thrombus length was in moderate agreement with the CTA-based reference standard [intraclass correlation coefficient (ICC) 0.73]., Conclusion: Automated detection of HAS and estimation of thrombus length on NCCT by the tested software is feasible with a sensitivity and specificity comparable to that of trained neuroradiologists., Competing Interests: MB: Unrelated: grants from Siemens, Stryker, Hopp foundation, grants, and personal fees from Novartis and Guerbet, personal fees from Merck, Teva, Grifols, BBraun, Boehringer Ingelheim, Vascular Dynamics, Springer, Bayer, all outside the submitted work. MM: Unrelated: Consultancy: Medtronic, MicroVention, Stryker; Payment for Lectures Including Service on Speakers Bureaus: Medtronic, MicroVention, Stryker. *Money paid to the institution. OJ: Head of the Scientific Research at Brainomix, Oxford, UK. PB: Deep learning researcher at Brainomix, Oxford, UK. PR: Unrelated: Consultancy: Boehringer, Lecture fees from Bayer, Boehringer Ingelheim, BMS, Daichii Sankyo, Pfizer. SN: Unrelated: Consultancy: Brainomix, Boehringer Ingelheim; Payment for Lectures Including Service on Speakers Bureaus: Pfizer, Medtronic, Bayer AG. CH: Related: Consultancy: Brainomix, Oxford, UK. OJ and PB were employed by Brainomix Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Weyland, Papanagiotou, Schmitt, Joly, Bellot, Mokli, Ringleb, Kastrup, Möhlenbruch, Bendszus, Nagel and Herweh.)

Objectives: Artif icial intelligence (AI)-based image analysis is increasingly applied in the acute stroke field. Its implementation for the detection and quantification of hemorrhage suspect hyperdensities in non-contrast-enhanced head CT (NCCT) scans may facilitate clinical decision-making and accelerate stroke management., Methods: NCCTs of 160 patients with suspected acute stroke were analyzed regarding the presence or absence of acute intracranial hemorrhages (ICH) using a novel AI-based algorithm. Read was performed by two blinded neuroradiology residents (R1 and R2). Ground truth was established by an expert neuroradiologist. Specificity, sensitivity, and area under the curve were calculated for ICH and intraparenchymal hemorrhage (IPH) detection. IPH-volumes were segmented and quantified automatically by the algorithm and semi-automatically. Intraclass correlation coefficient (ICC) and Dice coefficient (DC) were calculated., Results: In total, 79 of 160 patients showed acute ICH, while 47 had IPH. Sensitivity and specificity for ICH detection were 0.91 and 0.89 for the algorithm; 0.99 and 0.98 for R1; and 1.00 and 0.98 for R2. Sensitivity and specificity for IPH detection were 0.98 and 0.89 for the algorithm; 0.83 and 0.99 for R1; and 0.91 and 0.99 for R2. Interreader reliability for ICH and IPH detection showed strong agreements for the algorithm (0.80 and 0.84), R1 (0.96 and 0.84), and R2 (0.98 and 0.92), respectively. ICC indicated an excellent (0.98) agreement between the algorithm and the reference standard of the IPH-volumes. The mean DC was 0.82., Conclusion: The AI-based algorithm reliably assessed the presence or absence of acute ICHs in this dataset and quantified IPH volumes precisely., Key Points: • Artificial intelligence (AI) is able to detect hyperdense volumes on brain CTs reliably. • Sensitivity and specificity are highest for the detection of intraparenchymal hemorrhages. • Interreader reliability for hemorrhage detection shows strong agreement for AI and human readers., (© 2021. The Author(s).)

Purpose: We hypothesize that the detectability of early ischemic changes on non-contrast computed tomography (NCCT) is limited in hyperacute stroke for both human and machine-learning based evaluation. In short onset-time-to-imaging (OTI), the CT angiography collateral status may identify fast stroke progressors better than early ischemic changes quantified by ASPECTS., Methods: In this retrospective, monocenter study, CT angiography collaterals (Tan score) and ASPECTS on acute and follow-up NCCT were evaluated by two raters. Additionally, a machine-learning algorithm evaluated the ASPECTS scale on the NCCT (e-ASPECTS). In this study 136 patients from 03/2015 to 12/2019 with occlusion of the main segment of the middle cerebral artery, with a defined symptom-onset-time and successful mechanical thrombectomy (MT) (modified treatment in cerebral infarction score mTICI = 2c or 3) were evaluated., Results: Agreement between acute and follow-up ASPECTS were found to depend on OTI for both human (Intraclass correlation coefficient, ICC = 0.43 for OTI < 100 min, ICC = 0.57 for OTI 100-200 min, ICC = 0.81 for OTI ≥ 200 min) and machine-learning based ASPECTS evaluation (ICC = 0.24 for OTI < 100 min, ICC = 0.61 for OTI 100-200 min, ICC = 0.63 for OTI ≥ 200 min). The same applied to the interrater reliability. Collaterals were predictors of a favorable clinical outcome especially in hyperacute stroke with OTI < 100 min (collaterals: OR = 5.67 CI = 2.38-17.8, p < 0.001; ASPECTS: OR = 1.44, CI = 0.91-2.65, p = 0.15) while ASPECTS was in prolonged OTI ≥ 200 min (collaterals OR = 4.21,CI = 1.36-21.9, p = 0.03; ASPECTS: OR = 2.85, CI = 1.46-7.46, p = 0.01)., Conclusion: The accuracy and reliability of NCCT-ASPECTS are time dependent for both human and machine-learning based evaluation, indicating reduced detectability of fast stroke progressors by NCCT. In hyperacute stroke, collateral status from CT-angiography may help for a better prognosis on clinical outcome and explain the occurrence of futile recanalization., (© 2021. The Author(s).)

Background: The importance of an A1 aplasia remains unclear in stroke patients. In this work, we analyze the impact of an A1 aplasia contralateral to an acute occlusion of the distal internal carotid artery (ICA) on clinical outcomes. Methods: We conducted a retrospective study of consecutive stroke patients treated with mechanical thrombectomy at 12 tertiary care centers between January 2015 and February 2021 due to an occlusion of the distal ICA. Functional A1 aplasia was defined as the absence of A1 or hypoplastic A1 (>50% reduction to the contralateral site). Functional independence was measured by the modified Rankin Scale (mRS ≤ 2). Results: In total, 81 out of 1068 (8%) patients had functional A1 aplasia contralateral to distal ICA occlusion. Patients with functional contralateral A1 aplasia were more severely affected on admission (median NIHSS 18, IQR 15−23 vs. 17, IQR 13−21; aOR: 0.672, 95% CI: 0.448−1.007, p = 0.054) and post-interventional ischemic damage was larger (median ASPECTS 5, IQR 1−7, vs. 6, IQR 3−8; aOR: 1.817, 95% CI: 1.184−2.789, p = 0.006). Infarction occurred more often within the ipsilateral ACA territory (20/76, 26% vs. 110/961, 11%; aOR: 2.482, 95% CI: 1.389−4.437, p = 0.002) and both ACA territories (8/76, 11% vs. 5/961, 1%; aOR: 17.968, 95% CI: 4.979−64.847, p ≤ 0.001). Functional contralateral A1 aplasia was associated with a lower rate of functional independence at discharge (6/81, 8% vs. 194/965, 20%; aOR: 2.579, 95% CI: 1.086−6.122, p = 0.032) and after 90 days (5/55, 9% vs. 170/723, 24%; aOR: 2.664, 95% CI: 1.031−6.883, p = 0.043). Conclusions: A functional A1 aplasia contralateral to a distal ICA occlusion is associated with a poorer clinical outcome.

Background: Despite complete endovascular recanalization, a significant percentage of patients with acute anterior stroke do not achieve a good clinical outcome. We analyzed optimal thresholds of relevant parameters to discern functional independence after successful endovascular recanalization and test their predictive performance., Methods: Patients with acute anterior ischemic stroke undergoing endovascular treatment between April 2015 and November 2019 were retrospectively analyzed. Only patients with premorbid modified Rankin Scale (mRS) score <3 and complete recanalization (modified Thrombolysis In Cerebral Infarction 2c/3) were included. Optimal thresholds of the most important variables predicting functional independence (mRS 0-2 after 90 days) were calculated using receiver operating characteristic curves and their predictive performance was tested in an independent dataset using machine learning algorithms., Results: Overall, 371 patients met the inclusion criteria. Optimal thresholds for the overall most important variables to predict functional independence were (1) National Institutes of Health Stroke Scale (NIHSS) score ≤5 after 24 hours (area under the curve (AUC) 0.88 (95% CI 0.84 to 0.92)); (2) Alberta Stroke Program Early CT Score (ASPECTS) ≥7 on follow-up CT (AUC 0.72 (95% CI 0.68 to 0.77)); and (3) change in NIHSS score ≥8 after 24 hours (AUC 0.70 (95% CI 0.65 to 0.74)). The performance of these thresholds to predict a good outcome using machine learning in the independent dataset was evaluated for (1) NIHSS score ≤5 after 24 hours (AUC 0.76 (95% CI 0.71 to 0.81)); (2) follow-up ASPECTS ≥7 (AUC 0.64 (95% CI 0.58 to 0.70)); (3) change in NIHSS score ≥8 after 24 hours (AUC 0.61 (95% CI 0.55 to 0.67)); and (4) the combination of all three parameters (AUC 0.84 (95% CI 0.80 to 0.88))., Conclusions: After complete recanalization in acute anterior circulation ischemic stroke, a good long-term outcome could be accurately predicted reaching NIHSS score ≤5 after 24 hours., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

Background and Purpose: To investigate the reliability and accuracy of Alberta Stroke Program Early Computed Tomography Scores (ASPECTS) derived from flatpanel detector computed tomography pooled blood volume maps compared to non-contrast computed tomography and multidetector computed tomography perfusion cerebral blood volume maps., Methods: ASPECTS from pooled blood volume maps were evaluated retrospectively by two experienced readers for 37 consecutive patients with acute middle cerebral artery (MCA) M1 occlusion who underwent flatpanel detector computed tomography perfusion imaging before mechanical thrombectomy between November 2016 and February 2019. For comparison with ASPECTS from non-contrast computed tomography and cerebral blood volume maps, a matched-pair analysis according to pre-stroke modified Rankin scale, age, stroke severity, site of occlusion, time from stroke onset to imaging and final modified thrombolysis in cerebral infarction (mTICI) was performed in a separate group of patients who underwent multimodal computed tomography prior to mechanical thrombectomy between June 2015 and February 2019. Follow-up ASPECTS were derived from either non-contrast computed tomography or from magnetic resonance imaging (in seven patients) one day after mechanical thrombectomy., Results: Interrater agreement was best for non-contrast computed tomography ASPECTS (w-kappa = 0.74, vs. w-kappa = 0.63 for cerebral blood volume ASPECTS and w-kappa = 0.53 for pooled blood volume ASPECTS). Also, accuracy, defined as correlation between acute and follow-up ASPECTS, was best for non-contrast computed tomography ASPECTS (Spearman ρ = 0.86 (0.65-0.97), P  < 0.001), while it was lower and comparable for pooled blood volume ASPECTS (ρ = 0.58 (0.32-0.79), P  < 0.001) and cerebral blood volume ASPECTS (ρ = 0.52 (0.17-0.80), P  = 0.001). It was noteworthy that cases of relevant infarct overestimation by two or more ASPECTS regions (compared to follow-up imaging) were observed for both acute pooled blood volume and cerebral blood volume ASPECTS but occurred more often for acute pooled blood volume ASPECTS (25% vs. 5%, P  = 0.02)., Conclusion: Non-contrast computed tomography ASPECTS outperformed both pooled blood volume ASPECTS and cerebral blood volume ASPECTS in accuracy and reliability. Importantly, relevant infarct overestimation was observed more often in pooled blood volume ASPECTS than cerebral blood volume ASPECTS, limiting its present clinical applicability for acute stroke imaging.

Despite successful recanalization of large-vessel occlusions in acute ischemic stroke, individual patients profit to a varying degree. Dynamic susceptibility-weighted perfusion and dynamic T1-weighted contrast-enhanced blood-brain barrier permeability imaging may help to determine secondary stroke injury and predict clinical outcome. We prospectively performed perfusion and permeability imaging in 38 patients within 24 h after successful mechanical thrombectomy of an occlusion of the middle cerebral artery M1 segment. Perfusion alterations were evaluated on cerebral blood flow maps, blood-brain barrier disruption (BBBD) visually and quantitatively on k trans maps and hemorrhagic transformation on susceptibility-weighted images. Visual BBBD within the DWI lesion corresponded to a median k trans elevation (IQR) of 0.77 (0.41-1.4) min -1 and was found in all 7 cases of hypoperfusion (100%), in 10 of 16 cases of hyperperfusion (63%), and in only three of 13 cases with unaffected perfusion (23%). BBBD was significantly associated with hemorrhagic transformation (p < 0.001). While BBBD alone was not a predictor of clinical outcome at 3 months (positive predictive value (PPV) = 0.8 [0.56-0.94]), hypoperfusion occurred more often in patients with unfavorable clinical outcome (PPV = 0.43 [0.10-0.82]) compared to hyperperfusion (PPV = 0.93 [0.68-1.0]) or unaffected perfusion (PPV = 1.0 [0.75-1.0]). We show that combined perfusion and permeability imaging reveals distinct infarct signatures after recanalization, indicating the severity of prior ischemic damage. It assists in predicting clinical outcome and may identify patients at risk of stroke progression., (© 2021. The Author(s).)

Background and Purpose: To compare safety and efficacy of conscious sedation (CS) vs. general anesthesia (GA) in endovascular stroke treatment (EST) of the posterior circulation (PC). Methods: Retrospective single-center analysis of patients receiving EST for large-vessel occlusion (LVO) in PC between January 2015 and November 2020. Exclusion criteria were severe stroke syndromes (NIHSS > 20), decreased level of consciousness, intubation for transport, and second stroke within 3 months of follow-up. The primary endpoint was a favorable clinical outcome 90 days after stroke onset (mRS 0-2 or 3 if pre-stroke mRS 3). Secondary endpoints were the rate of EST failure and procedural complications. Results: Of 111 included patients, 45/111 patients (40.5%) were treated under CS and 60/111 (54.0%) under GA. In 6/111 cases (5.4%), sedation mode was changed from CS to GA during EST. Patients treated under CS showed a lower mRS 90 days after stroke onset [mRS, median (IQR): 2.5 (1-4) CS vs. 3 (2-6) GA, p = 0.036] and a comparable rate of good outcome [good outcome, n (%): 19 (42.2) CS vs. 15 (32.6) GA, p = 0.311]. There was no difference in complication rates during EST (6.7% CS vs. 8.3% GA) or intracranial bleeding in follow-up imaging [ n (%): 4 (8.9) CS vs. 7 (11.7) GA), p = 0.705]. The rate of successful target vessel recanalization did not differ (84.4% CS vs. 85.0 % GA). Conclusions: In this retrospective study, EST of the posterior circulation under conscious sedation was for eligible patients comparably safe and effective to patients treated under general anesthesia., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Weyland, Chen, Potreck, Jäger, Seker, Schönenberger, Bendszus and Möhlenbruch.)

Background and Purpose: To determine reasons for failed recanalization in mechanical thrombectomy (MT) of the posterior circulation., Methods: Retrospective single center analysis of reasons for MT failure in the posterior circulation. Failed MTs were categorized according to the reason for procedure failure in failed vascular access, failed passage of the target vessel occlusion and MT failure after passing the occluded target vessel. Patient characteristics were compared between failed and successful MT., Results: Patients with failed MT (30/218 patients, 13.8%) were categorized into futile vascular access (13/30, 43.3%), abortive passage of the target vessel occlusion (6/30, 20.0%) and MT failure after passing the vessel occlusion (11/30, 36.7%). In 188/218 (86.2%) successful MTs alternative vascular access, local intra-arterial (i.a.) thrombolysis and emergency stent-assisted PTA prevented 65 MT failures. Patients with failed MT showed a higher NIHSS at discharge, a higher pc-ASPECTS in follow-up imaging, a higher mRS 90 days after stroke onset and a high mortality rate of 77.0% (mRS at 90 days, median (IQR): 6 (6-6) vs. 4 (2-6) for successful MT, p-value < 0.001). Co-morbidities and stroke etiology were not different compared to sufficient recanalization with atherosclerotic disease as the leading stroke etiology in both groups., Conclusion: Failure of MT in posterior circulation ischemic stroke patients is associated with a high mortality rate. Reasons for MT failure are diverse with futile vascular access and MT failure after passing the vessel occlusion as the leading causes. Alternative vascular access, local i.a. thrombolysis and stent-assisted PTA can prevent MT failure., (© 2020. The Author(s).)

Background: The application of a new coating to the delivery wire of the Trevo retriever has the potential to improve its handling. We therefore report our initial experience with this new stent retriever for mechanical thrombectomy of large and medium vessel occlusions. Methods: We pooled data of four high-volume European stroke centers over the time period from October 2020 to February 2021. Patients were included in our study if the Trevo NXT stent retriever was used as a first-line device. Primary endpoints were first-pass near-complete or complete reperfusion, defined as mTICI score of ≥2c. Secondary endpoints were final reperfusion, National Institutes of Health Stroke Scale (NIHSS) at 24 h and discharge, device malfunctions, complications during the procedure, and subjective ratings of the interventionalists regarding device functionality. Results: Eighty patients (39 women, mean age 74 ± 14 years) were eligible for our study. Median NIHSS at admission was 15 (IQR, 8-19), and median Alberta Stroke Program Early CT Score at baseline was 9 (IQR, 8-10). In 74 (93%) patients a primary combined approach was used as first-line technique. First-pass near-complete reperfusion was achieved in 43 (54%) and first-pass complete reperfusion in 34 (43%) patients. Final near-complete reperfusion was achieved in 66 (83%) patients after a median of 1.5 (1-3) passes, while final successful reperfusion was observed in 96% of our cases. We observed no device malfunctions. Median NIHSS at discharge was 2 (IQR, 0-5), and 3 patients (4%) suffered a symptomatic intracranial hemorrhage. Conclusions: Based on our initial data, we conclude that the Trevo NXT is an effective and safe tool for mechanical thrombectomy especially when used for combined approaches., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Etter, Möhlenbruch, Weyland, Pérez-García, Moreu, Capasso, Limbucci, Nikoubashman, Wiesmann, Blackham, Tsogkas, Sporns, Ospel, Brehm and Psychogios.)

Background and Purpose: Failure of early neurological improvement (fENI) despite successful mechanical thrombectomy in the anterior circulation is a clinically frequent occurrence. Purpose of this analysis was to define independent clinical, radiological, laboratory, or procedural predictors for fENI., Methods: Retrospective single-center analysis of patients treated for acute ischemic stroke in the anterior circulation ensuing successful mechanical thrombectomy between January 2014 and April 2019. Patients were compared according to fENI (equal or higher National Institutes of Health Stroke Scale) and ENI (lower National Institutes of Health Stroke Scale at discharge). Thirty-eight variables were examined in multivariable analysis for association with fENI., Results: Five hundred forty-nine out of 1146 patients experienced successful recanalization (modified Treatment in Cerebral Ischemia 2c-3). fENI occurred in 115/549 (20.9%) patients. Independent predictors of fENI were premorbid modified Rankin Scale (odds ratio [OR] per point [IC], 1.21 [1.00-1.46], P =0.049), end-stage renal failure (OR [IC], 12.18 [2.01-73.63], P =0.007), admission glucose (OR [IC], 1.018 [1.004-1.013] per mg/dL, P =0.001), bridging IV lysis (OR [IC], 0.57 [0.35-0.93], P : 0.024), time from groin puncture to final recanalization (OR [IC], 1.004 [1.001-1.007] per minute, P =0.015), general anesthesia during mechanical thrombectomy (OR, 2.41 [1.43-4.08], P <0.001), symptomatic intracranial hemorrhage (OR [CI], 6.81 [1.84-25.16], P =0.004), and follow-up Alberta Stroke Program Early CT Score (OR [IC], 0.76 [0.69-0.84] per point, P <0.001). In a secondary analysis, involvement of the regions internal capsule, M4 and M5 (motor cortex) were further independent predictors for fENI. Patients with ENI were more likely to experience a good outcome (modified Rankin Scale on day 90, 0-2: n=229/435 [52.8%] versus n=13/115 [11.3%]; P <0.001)., Conclusions: The extent of infarction and the involvement of motor cortex and internal capsule as well as higher premorbid modified Rankin Scale, end-stage renal failure, high glucose level on admission, absence of bridging IV lysis, general anesthesia, and a longer therapy interval are presumably independent predictors for fENI in patients with successful mechanical thrombectomy.

Importance: Clinical evidence of the potential treatment benefit of mechanical thrombectomy for posterior circulation distal, medium vessel occlusion (DMVO) is sparse., Objective: To investigate the frequency as well as the clinical and safety outcomes of mechanical thrombectomy for isolated posterior circulation DMVO stroke and to compare them with the outcomes of standard medical treatment with or without intravenous thrombolysis (IVT) in daily clinical practice., Design, Setting, and Participants: This multicenter case-control study analyzed patients who were treated for primary distal occlusion of the posterior cerebral artery (PCA) of the P2 or P3 segment. These patients received mechanical thrombectomy or standard medical treatment (with or without IVT) at 1 of 23 comprehensive stroke centers in Europe, the United States, and Asia between January 1, 2010, and June 30, 2020. All patients who met the inclusion criteria were matched using 1:1 propensity score matching., Interventions: Mechanical thrombectomy or standard medical treatment with or without IVT., Main Outcomes and Measures: Clinical end point was the improvement of National Institutes of Health Stroke Scale (NIHSS) scores at discharge from baseline. Safety end point was the occurrence of symptomatic intracranial hemorrhage and hemorrhagic complications were classified based on the Second European-Australasian Acute Stroke Study (ECASSII). Functional outcome was evaluated with the modified Rankin Scale (mRS) score at 90-day follow-up., Results: Of 243 patients from all participating centers who met the inclusion criteria, 184 patients were matched. Among these patients, the median (interquartile range [IQR]) age was 74 (62-81) years and 95 (51.6%) were female individuals. Posterior circulation DMVOs were located in the P2 segment of the PCA in 149 patients (81.0%) and in the P3 segment in 35 patients (19.0%). At discharge, the mean NIHSS score decrease was -2.4 points (95% CI, -3.2 to -1.6) in the standard medical treatment cohort and -3.9 points (95% CI, -5.4 to -2.5) in the mechanical thrombectomy cohort, with a mean difference of -1.5 points (95% CI, 3.2 to -0.8; P = .06). Significant treatment effects of mechanical thrombectomy were observed in the subgroup of patients who had higher NIHSS scores on admission of 10 points or higher (mean difference, -5.6; 95% CI, -10.9 to -0.2; P = .04) and in the subgroup of patients without IVT (mean difference, -3.0; 95% CI, -5.0 to -0.9; P = .005). Symptomatic intracranial hemorrhage occurred in 4 of 92 patients (4.3%) in each treatment cohort., Conclusions and Relevance: This study suggested that, although rarely performed at comprehensive stroke centers, mechanical thrombectomy for posterior circulation DMVO is a safe, and technically feasible treatment option for occlusions of the P2 or P3 segment of the PCA compared with standard medical treatment with or without IVT.

Purpose: To determine the radiation exposure in endovascular stroke treatment (EST) of acute basilar artery occlusions (BAO) and compare it with radiation exposure of EST for embolic middle cerebral artery occlusions (MCAO)., Methods: In this retrospective analysis of an institutional review board-approved prospective stroke database of a comprehensive stroke center, we focused on radiation exposure (as per dose area product in Gy × cm 2 , median (IQR)), procedure time, and fluoroscopy time (in minutes, median [IQR]) in patients receiving EST for BAO. Patients who received EST for BAO were matched case by case with patients who received EST for MCAO according to number of thrombectomy attempts, target vessel reperfusion result, and thrombectomy technique., Results: Overall 180 patients (n = 90 in each group) were included in this analysis. General anesthesia was conducted more often during EST of BAO (BAO: 75 (83.3%); MCAO: 18 (31.1%), p < 0.001). Procedure time (BAO: 31 (20-43); MCAO: 27 (18-38); p value 0.226) and fluoroscopy time (BAO: 29 (20-59); MCAO: 29 (17-49), p value 0.317) were comparable. Radiation exposure was significantly higher in patients receiving EST for BAO (BAO: 123.4 (78.7-204.2); MCAO: 94.3 (65.5-163.7), p value 0.046), which represents an increase by 23.7%., Conclusion: Endovascular stroke treatment of basilar artery occlusions is associated with a higher radiation exposure compared with treatment of middle cerebral artery occlusions.

Objective: To quantify radiation exposure (RE) of endovascular stroke treatment (EST) in the anterior circulation per thrombectomy attempt and determine causes for interventions associated with high RE., Methods: A retrospective single-center study of an institutional review board-approved stroke database of patients receiving EST for large vessel occlusions in the anterior circulation between January 2013 and April 2018 to evaluate reference levels (RL) per thrombectomy attempt. ESTs with RE above the RL were analyzed to determine causes for high RE., Results: Overall, n = 544 patients (occlusion location, M1 and M2 segments of the middle cerebral artery 53.5% and 27.2%, carotid artery 17.6%; successful recanalization rate 85.7%) were analyzed. In the overall population, DAP (in Gy cm 2 , median (IQR)) was 113.7 (68.9-181.7) with a median fluoroscopy time of 31 min (IQR, 17-53) and a median of 2 (IQR, 1-4) thrombectomy attempts. RE increased significantly with every thrombectomy attempt (DAP 1 , 68.7 (51.2-106.8); DAP 2 , 106.4 (84.8-115.6); p value 1vs2 , < 0.001; DAP 3 , 130.2 (89.1-183.6); p value 2vs3 , 0.044; DAP 4 , 169.9 (128.4-224.1); p value 3vs4 , 0.001; and DAP 5 , 227.6 (146.3-294.6); p value 4vs5 , 0.019). Procedures exceeding the 90th percentile of the attempt-dependent radiation exposure level were associated with procedural complications (n = 17/52, 29.8%) or a difficult vascular access (n = 8/52, 14%)., Conclusions: Radiation exposure in endovascular stroke treatment is depending on the number of thrombectomy attempts. Radiation exposure doubles when three attempts and triples when five attempts are necessary compared with single-maneuver interventions. Procedural complications and difficult vascular access were associated with a high radiation exposure in this collective., Key Points: • Radiation exposure of endovascular stroke treatment (EST) is dependent on the number of thrombectomy attempts. • Reference levels as means for quality control in hospitals performing endovascular stroke treatment should be defined by the number of thrombectomy attempts-we suggest 107 Gy cm 2 , 156 Gy cm 2 , 184 Gy cm 2 , 244 Gy cm 2 , and 295 Gy cm 2 for 1 to 5 maneuvers, respectively, for EST of the anterior circulation • Cases with high rates of radiation exposure are associated with periprocedural complications and difficult anatomical access as a probable cause for a high radiation exposure.

Objective: This study aimed to compare radiation exposure (RE) in patients receiving mechanical thrombectomy (MT) for large-vessel occlusions in the anterior circulation using direct thrombo-aspiration (DT) versus stent-retriever thrombectomy under continuous distal aspiration (STA)., Methods: This was a retrospective single-centre analysis of an Institutional Review Board-approved stroke database of a comprehensive stroke centre focusing on RE per dose area product, procedure time (PT) and fluoroscopy time (FT) in patients receiving MT. Patients who received MT with DT were matched with patients treated using STA according to occlusion location, mode of anaesthesia, manoeuvre count and sex., Results: Apart from patient age (DT: M  = 74 years (standard deviation ( SD )=13 years); STA: M  = 79 years ( SD  = 11 years); p  = 0.023), there was no difference in baseline patient characteristics ( n  = 68 per group). PT (DT: median = 26 minutes (interquartile range (IQR) = 21-38 minutes); STA: median = 49 minutes (IQR 37-77 minutes); p  < 0.0001) and FT (DT: median = 12 minutes (IQR 7-18 minutes); STA: median = 26 minutes (IQR 14-43 minutes); p  < 0.0001) were shorter in patients who received MT using DT. RE (DT: median = 62.6 Gy·cm 2 (IQR 41.7-89.4 Gy·cm 2 ); STA: median = 89.8 Gy·cm 2 (IQR 53.7-131.7 Gy·cm 2 ); p  = 0.034) was significantly lower in patients who received MT using DT. This represents a relative increase of RE, FT and PT by 43.6%, 116.6% and 88.5%, respectively, in patients who received MT using STA., Conclusion: MT using DT is associated with shorter FT and PT and lower RE compared to matched patients treated with STA.

Purpose: To determine the effect of general anesthesia (GA) versus conscious sedation (CS) on radiation exposure (RE), procedure time (PT), and fluoroscopy time (FT) in patients receiving endovascular stroke treatment (EST) for large vessel occlusions (LVOs) in the anterior circulation., Methods: Retrospective analysis of an institutional review board-approved prospective stroke database of a comprehensive stroke center focusing on RE (as dose area product (DAP) in Gy.cm², median (IQR)), PT, and FT (in minutes, median (IQR)) in patients receiving EST for LVOs of the anterior circulation according to the mode of anesthesia during the intervention., Results: Overall 544 patients were included in this analysis (GA: n=143, CS: n=401). For all included LVOs in the anterior circulation PTs (GA: 69 (44-100); CS: 59 (37-99); p=0.235), FTs (GA: 33 (20-56); CS: 29 (16-51); p=0.286), and RE (DAP, GA: 116.23 (73.47-173.41); CS: 110.5 (68.35-184.65); p=0.929) were comparable. In a subgroup analysis of occlusions of the middle cerebral artery (M1-segment; GA: n=80/544, 14.7%; CS: n=211/544, 38.8%), PTs (GA: 69 (37-101); CS: 54 (35 - 89); p=0.223), FTs (GA: 33 (19-55); CS: 25 (14-48); p=0.264), and RE (DAP, GA: 110.91 (66.8-169.12); CS: 103.8 (63.17-181); p=0.893) were similar., Conclusion: In this retrospective analysis, no effect of the mode of anesthesia on the radiation exposure during EST was detected as GA and CS showed comparable PT, FT, and DAPs., Competing Interests: Competing interests: PAR: reports personal fees from Boehringer Ingelheim, Bayer, BMS, Daiichi Sankyo, and Covidien, outside the submitted work. MM: unrelated: board membership: Codman; consultancy: Medtronic, MicroVention, Stryker; grants/grants pending: Balt*, MicroVention*; payment for lectures Including service on speakers bureaus: Medtronic, MicroVention, Stryker. *Money paid to the institution. MB: activities related to this article: disclosed no relevant relationships. Activities not related to this article: grants and personal fees from Bayer, Codman, Guerbet, Medtronic, and Novartis; grants from the Hopp Foundation, Siemens, and Stryker; personal fees from Braun, Böhringer Ingelheim, Roche, Teva, and Vascular Dynamics. Other relationships: disclosed no relevant relationships. JARP: activities related to the present article: disclosed no relevant relationships. Activities not related to the present article: travel and meeting expenses from Stryker and MicroVention. Other relationships: disclosed no relevant relationships., (© Author(s) (or their employer(s)) 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

Purpose: To quantify the influence of interventionalist's experience on procedure time, radiation exposure, and fluoroscopy time during mechanical thrombectomy (MT) in the anterior circulation., Methods: Retrospective analysis of an institutional review board-approved stroke database of a comprehensive stroke center focusing on radiation exposure (as per dose area product in Gy × cm 2 , median [IQR]), procedure, and fluoroscopy time (in minutes, median [IQR]) in patients receiving MT in anterior circulation ischemic stroke. Procedures have been assigned according to the interventionalist's experience in MT into three sequential groups: A = 1-25 procedures, B = 26-50 procedures, and C = more than 50 procedures., Results: Overall, 696 patients have been included in this analysis (A, n = 152; B, n = 151; C, n = 393). Procedure times (A, 86 [54-131]; B, 67 [48-103], p value 0.006), fluoroscopy times (A, 39 [25-72]; B, 32 [20-53], p value 0.001) as well as radiation exposure (A, 148.13 [89.58-243.37]; B, 111.60 [70.49-180.57], p value 0.001) were significantly shorter, respectively lower in group B than in group A. Procedure times (C, 59 [36-99]), fluoroscopy times (C, 31 [16-53]), and radiation exposure (C, 113.91 [68.48-182.88]) in group C were also significantly shorter/lower than in group A (all p values < 0.0001), but comparable with group B (p values 0.071, 0.809, and 0.934)., Conclusion: This retrospective analysis demonstrates a significant influence of interventionalist's experience on procedure time, fluoroscopy time, and radiation exposure in mechanical thrombectomy in the anterior circulation., Key Points: • There is a significant influence of interventionalist's experience on procedure time, fluoroscopy time, and radiation exposure in mechanical thrombectomy in the anterior circulation. • Interventionalists' learning curve is steepest during the first 25 cases. • These circumstances should be considered when reference levels or guide values are established and in training of physicians performing mechanical thrombectomy to promote optimization of patient doses in the future.