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Background: Traditionally, non-contrast computed tomography (CT) alone was used in the initial assessment of acute ischaemic stroke patients mainly to exclude haemorrhage or alternative pathology. Summary: Late-window (beyond 6 h) and recent large-volume endovascular mechanical thrombectomy (MT) trials integrated CT perfusion (CTP) imaging to guide MT and/or intravenous thrombolysis decision-making in stroke patients. Key Messages: In current clinical practice, many patients are being excluded from reperfusion therapy due to a lack of data from urgent investigations to assess cerebral vasculature and perfusion. Here, we explore the potential benefits of CTP incorporated into the initial CT protocol assessment of stroke patients. [ABSTRACT FROM AUTHOR]

Background With the expanding eligibility for endovascular therapy (EVT) of patients presenting in the late window (6–24 hours after last known well), we aimed to derive a score to predict favorable outcomes associated with EVT versus best medical management. Methods and Results A multinational observational cohort of patients from the CLEAR (Computed Tomography for Late Endovascular Reperfusion) study with proximal intracranial occlusion (2014–2022) was queried (n=58 sites). Logistic regression analyses were used to derive a 9‐point score for predicting good functional outcome (modified Rankin Scale score 0–2 or return to premorbid modified Rankin Scale score) at 90 days, with sensitivity analyses for prespecified subgroups conducted using bootstrapped random forest regressions. Secondary outcomes included 90‐day functional independence (modified Rankin Scale score 0–2), poor outcome (modified Rankin Scale score 5–6), and 90‐day survival. The score was externally validated with a single‐center cohort (2014–2023). Of the 3231 included patients (n=2499 EVT), a 9‐point score included age, early computed tomography ischemic changes, and stroke severity, with higher points indicating a higher probability of a good functional outcome. The areas under the curve for the primary outcome among EVT and best medical management subgroups were 0.72 (95% CI, 0.70–0.74) and 0.87 (95% CI, 0.84–0.90), respectively, with similar performance in the external validation cohort (area under the curve, 0.71 [95% CI, 0.66–0.76]). There was a significant interaction between the score and EVT for good functional outcome, functional independence, and poor outcome (all Pinteraction

Background and Purpose Effect of endovascular therapy (EVT) in acute large vessel occlusion (LVO) patients with tandem lesions (TLs) within 6–24 hours after last known well (LKW) remains unclear. We evaluated the clinical and safety outcomes among TL-LVO patients treated within 6–24 hours. Methods This multicenter cohort was divided into two groups, based on LKW to puncture time: early window (

Background: The proper imaging modality for use in the selection of patients for endovascular thrombectomy (EVT) presenting in the late window remains controversial, despite current guidelines advocating the use of advanced imaging in this population. We sought to understand if clinicians with different specialty training differ in their approach to patient selection for EVT in the late time window. Methods: We conducted an international survey of stroke and neurointerventional clinicians between January and May 2022 with questions focusing on imaging and treatment decisions of large vessel occlusion (LVO) patients presenting in the late window. Interventional neurologists, interventional neuroradiologists, and endovascular neurosurgeons were defined as interventionists whereas all other specialties were defined as non-interventionists. The non-interventionist group was defined by all other specialties of the respondents: stroke neurologist, neuroradiologist, emergency medicine physician, trainee (fellows and residents) and others. Results: Of 3000 invited to participate, 1506 (1027 non-interventionists, 478 interventionists, 1 declined to specify) physicians completed the study. Interventionist respondents were more likely to proceed directly to EVT (39.5% vs. 19.5%; p < 0.0001) compared to non-interventionist respondents in patients with favorable ASPECTS (Alberta Stroke Program Early CT Score). Despite no difference in access to advanced imaging, interventionists were more likely to prefer CT/CTA alone (34.8% vs. 21.0%) and less likely to prefer CT/CTA/CTP (39.1% vs. 52.4%) for patient selection (p < 0.0001). When faced with uncertainty, non-interventionists were more likely to follow clinical guidelines (45.1% vs. 30.2%) while interventionists were more likely to follow their assessment of evidence (38.7% vs. 27.0%) (p < 0.0001). Conclusion: Interventionists were less likely to use advanced imaging techniques in selecting LVO patients presenting in the late window and more likely to base their decisions on their assessment of evidence rather than published guidelines. These results reflect gaps between interventionists and non-interventionists reliance on clinical guidelines, the limits of available evidence, and clinician belief in the utility of advanced imaging. [ABSTRACT FROM AUTHOR]

Introduction: Endovascular treatment (EVT) for acute ischemic stroke (AIS) between 6 and 24 h is established as a standard of care among patients selected by multiparametric neuroimaging. We aimed to explore neuroimaging parameters in late-window large vessel occlusion (LVO) patients and its association with non-contrast computed tomography (NCCT) findings. Methods: We included consecutive AIS patients within 6–24 h from the symptoms onset with LVO. We described multiparametric imaging findings, the rate of patients who fulfilled imaging perfusion criteria according to the DAWN and DEFUSE-3 trials that define the computed tomography perfusion mismatch (CTP-MM) group and its association with NCCT focused on Alberta Stroke Program Early CT Score (ASPECTS). We also analyzed the association between neuroimaging parameters and the clinical outcome determined by the 90-day modified Rankin scale (mRS). Results: We included 206 patients, of them, 176 (85.4%) presented CTP-MM and 184 (89.3%) presented an ASPECTS ≥6 on admission. The rate of CTP-MM was 90.8% in patients with ASPECTS ≥6, compared with 40.9% in those with low ASPECTS. ASPECTS was moderately correlated with ischemic core determined by cerebral blood flow <30% volume (rS = −0.557, p < 0.001). In EVT-treated patients (185, 89.8%), after adjusting for identifiable confounders, the presence of CTP-MM was a predictor of 90-day functional independence (OR: 3.38; 95% CI: 1.01–11.29; p = 0.048). We did not find an association between CTP-MM and 90-day functional disability (ordinal mRS shift, aOR: 1.39; 95% CI: 0.58–3.34; p = 0.459). Conclusions: A great majority of patients who presented a LVO in the late window fulfilled guidelines imaging criteria to undergo EVT, especially those with high ASPECTS (≥6). Our data suggest that NCCT with CT angiography could be a reasonable approach for AIS treatment selection also in the late window. [ABSTRACT FROM AUTHOR]

Background Current stroke guidelines recommend advanced imaging (computed tomography [CT] perfusion or magnetic resonance imaging) prior to endovascular therapy (EVT) in patients with late presentation of large vessel occlusion. Adherence to guidelines may be constrained by resources or timely access to imaging. We sought to understand the factors which influence late window imaging selection for EVT candidates with large vessel occlusion. Methods We conducted an international survey from January to May 2022. The questions aimed to identify advanced imaging and treatment decisions based on access to imaging, time delays, and simulated patient scenarios. Results There were 3000 invited participants and 1506 respondents, the majority (89.6%) from comprehensive stroke centers in high‐income countries. Neurointerventionalists comprised 31.8% and noninterventionalists 68.2% of respondents. Overall, 70.7% reported routine use of advanced imaging for late EVT selection, and 63.6% reported its usage in every case. There was greater availability of advanced imaging in comprehensive stroke centers versus primary stroke centers (67.0% versus 33.7%; P

Background Recent clinical trials investigating endovascular therapy in the extended time window have opened new treatment paradigms for patients with late‐presenting large vessel occlusion stroke. The aim of this guideline is to provide up‐to‐date recommendations for the diagnosis, selection, and medical or endovascular treatment of patients with large vessel occlusion presenting in the extended time window. Methods The Society of Vascular and Interventional Neurology Guidelines and Practice Standards committee assembled a writing group and recruited interdisciplinary experts to review and evaluate the current literature. Recommendations were assigned by the writing group using the Society of Vascular and Interventional Neurology Guidelines and Practice Standards Class of Recommendation/Level of Evidence algorithm and Society of Vascular and Interventional Neurology Guidelines and Practice Standards guideline format. The final guideline was approved by all members of the writing group, the Guidelines and Practice Standards committee, and the Society of Vascular and Interventional Neurology board of directors. Results Literature review yielded 3 high‐quality randomized trials and several observational studies that have been extracted to derive the enclosed summary recommendations. In patients with large vessel occlusion presenting in the 6‐ to 24‐hour window and with clinical–imaging mismatch as defined by the DAWN (Diffusion‐Weighted Imaging or Computed Tomography Perfusion Assessment With Clinical Mismatch in the Triage of Wake‐Up and Late Presenting Strokes Undergoing Neurointervention With Trevo) and DEFUSE 3 (Endovascular Therapy Following Imaging Evaluation for Ischemic Stroke) studies, endovascular therapy is recommended. Noncontrast computed tomography can be used to evaluate infarct size as the sole imaging modality for patient selection, particularly when access to computed tomography perfusion or magnetic resonance imaging is limited or if their performance would incur substantial delay to treatment. In addition, several clinical questions were reviewed based on the available evidence and consensus grading. Conclusions These guidelines provide practical recommendations based on recent evidence on the diagnosis, selection, and treatment of patients with large vessel occlusion stroke presenting in the extended time window.

Introduction: The impact of leptomeningeal collateralization on the efficacy of mechanical thrombectomy (MT) in patients with anterior circulation large vessel occlusion (aLVO) presenting in the 6-24 h time window remains poorly elucidated., Patients and Methods: Retrospective multicenter study of aLVO patients presenting between 6 and 24 h after stroke onset who received MT plus Best Medical Treatment (BMT) or BMT alone. Leptomeningeal collateralization was assessed using single-phase computed tomography angiography (grade 0: no filling; grade 1: filling ⩽50%; grade 2: filling >50% but <100%; grade 3: filling 100% of the occluded territory). Inverse probability of treatment weighted ordinal regression was performed to assess the association between treatment and shift of the modified Rankin Scale (mRS) score toward lower categories at 3 months. We used interaction analysis to explore differential treatment effects on functional outcomes (probabilities for each mRS subcategory at 3 months) at different collateral grades., Results: Among 363 included patients, 62% received MT + BMT. Better collateralization was associated with better functional outcomes at 3 months in the BMT alone group (collateral grade 1 vs 0: acOR 5.06, 95% CI 2.33-10.99). MT + BMT was associated with higher odds of favorable functional outcome at 3 months (acOR 1.70, 95% CI 1.11-2.62) which was consistent after adjustment for collateral status (acOR 1.54, 95% CI 1.01-2.35). Regarding treatment effect modification, patients with absent collateralization had higher probabilities for a mRS of 0-4 and a lower mortality at 3 months for the MT + BMT group., Discussion and Conclusion: In the 6-to-24-h time window, aLVO patients with absent leptomeningeal collateralization benefit most from MT + BMT, indicating potential advantages for this group despite their poorer baseline prognosis., Competing Interests: Declaration of conflicting interestThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: MK received speaker honoraria from Medtronic. GMK is on a scientific advisory board of Bayer AG. CWC is member of the Medical and Scientific Advisory Boards of iSchemaView. LHB received personal fees from Claret Medical and InnovHeart. GMDM received speaker honoraria from Medtronic. The remaining authors report no conflicts of interests relevant to this study.

Background: With the expanding eligibility for endovascular therapy (EVT) of patients presenting in the late window (6-24 hours after last known well), we aimed to derive a score to predict favorable outcomes associated with EVT versus best medical management., Methods and Results: A multinational observational cohort of patients from the CLEAR (Computed Tomography for Late Endovascular Reperfusion) study with proximal intracranial occlusion (2014-2022) was queried (n=58 sites). Logistic regression analyses were used to derive a 9-point score for predicting good functional outcome (modified Rankin Scale score 0-2 or return to premorbid modified Rankin Scale score) at 90 days, with sensitivity analyses for prespecified subgroups conducted using bootstrapped random forest regressions. Secondary outcomes included 90-day functional independence (modified Rankin Scale score 0-2), poor outcome (modified Rankin Scale score 5-6), and 90-day survival. The score was externally validated with a single-center cohort (2014-2023). Of the 3231 included patients (n=2499 EVT), a 9-point score included age, early computed tomography ischemic changes, and stroke severity, with higher points indicating a higher probability of a good functional outcome. The areas under the curve for the primary outcome among EVT and best medical management subgroups were 0.72 (95% CI, 0.70-0.74) and 0.87 (95% CI, 0.84-0.90), respectively, with similar performance in the external validation cohort (area under the curve, 0.71 [95% CI, 0.66-0.76]). There was a significant interaction between the score and EVT for good functional outcome, functional independence, and poor outcome (all P interaction <0.001), with greater benefit favoring patients with lower and midrange scores., Conclusions: This score is a pragmatic tool that can estimate the probability of a good outcome with EVT in the late window., Registration: URL: https://www.Clinicaltrials.gov; Unique identifier: NCT04096248.

Background: The MR CLEAN-LATE trial has shown that patient selection for endovascular treatment (EVT) in the late window (6-24 h after onset or last-seen-well) based on the presence of collateral flow on CT-angiography is safe and effective. We aimed to assess the cost-effectiveness of late-window collateral-based EVT-selection compared to best medical management (BMM) over a lifetime horizon (until 95 years of age)., Materials and Methods: A model-based economic evaluation was performed from a societal perspective in The Netherlands. A decision tree was combined with a state-transition (Markov) model. Health states were defined by the modified Rankin Scale (mRS). Initial probabilities at 3-months post-stroke were based on MR CLEAN-LATE data. Transition probabilities were derived from previous literature. Information on short- and long-term resource use and utilities was obtained from a study using MR CLEAN-LATE and cross-sectional data. All costs are expressed in 2022 euros. Costs and quality-adjusted life years (QALYs) were discounted at a rate of 4% and 1.5%, respectively. The effect of parameter uncertainty was assessed using probabilistic sensitivity analysis (PSA)., Results: On average, the EVT strategy cost €159,592 (95% CI: €140,830-€180,154) and generated 3.46 QALYs (95% CI: 3.04-3.90) per patient, whereas the costs and QALYs associated with BMM were €149,935 (95% CI: €130,841-€171,776) and 2.88 (95% CI: 2.48-3.29), respectively. The incremental cost-effectiveness ratio per QALY and the incremental net monetary benefit were €16,442 and €19,710, respectively. At a cost-effectiveness threshold of €50,000/QALY, EVT was cost-effective in 87% of replications., Discussion and Conclusion: Collateral-based selection for late-window EVT is likely cost-effective from a societal perspective in The Netherlands., Competing Interests: Declaration of conflicting interestThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: This study was supported by a grant from the Dutch organization for Health research and Health innovation (ZonMw). H.B. received consultation fees from Stryker Neurovascular (paid to the institution). A.P. received an institutional grant from Siemens Healthineers and Bayer Healthcare. W.Z. received consultation fees from Stryker, Nicolab and Cerenovus (paid to the institution), and is a DSMB member of the Philips’ We-Trust study, Anaconda’s Solonda study, and In Extremis study (all funding paid to the institution).

Background and Purpose: Effect of endovascular therapy (EVT) in acute large vessel occlusion (LVO) patients with tandem lesions (TLs) within 6-24 hours after last known well (LKW) remains unclear. We evaluated the clinical and safety outcomes among TL-LVO patients treated within 6-24 hours., Methods: This multicenter cohort was divided into two groups, based on LKW to puncture time: early window (<6 hours), and late window (6-24 hours). Primary clinical and safety outcomes were 90-day functional independence measured by the modified Rankin Scale (mRS: 0-2) and symptomatic intracranial hemorrhage (sICH). Secondary outcomes were successful reperfusion (modified Thrombolysis in Cerebral Infarction score ≥2b), first-pass effect, early neurological improvement, ordinal mRS, and in-hospital and 90-day mortality., Results: Of 579 patients (median age 68, 32.1% females), 268 (46.3%) were treated in the late window and 311 (53.7%) in the early window. Late window group had lower median National Institutes of Health Stroke Scale score at admission, Alberta Stroke Program Early Computed Tomography Score, rates of intravenous thrombolysis, and higher rates for perfusion imaging. After adjusting for confounders, the odds of 90-day mRS 0-2 (47.7% vs. 45.0%, adjusted odds ratio [aOR] 0.71, 95% confidence interval [CI] 0.49-1.02), favorable shift in mRS (aOR 0.88, 95% CI 0.44-1.76), and sICH (3.7% vs. 5.2%, aOR 0.56, 95% CI 0.20-1.56) were similar in both groups. There was no difference in secondary outcomes. Increased time from LKW to puncture did not predicted the probability of 90-day mRS 0-2 (aOR 0.99, 95% CI 0.96-1.01, for each hour delay) among patients presenting <24 hours., Conclusion: EVT for acute TL-LVO treated within 6-24 hours after LKW was associated with similar rates of clinical and safety outcomes, compared to patients treated within 6 hours.

Multiple trials have shown that mechanical thrombectomy (MT) is superior to medical therapy. However, no robust evidence is available regarding MT beyond 24 h. In this study, we aimed to determine the safety and efficacy of endovascular stroke therapy in this late window. We conducted a retrospective study of prospectively collected data of patients who met extended window trial criteria, but underwent MT beyond 24 h. Safety and efficacy outcomes included symptomatic intracerebral hemorrhage (sICH), procedural complications, number of passes, successful recanalization (mTICI 2b − 3), delta (Δ) NIHSS (baseline-discharge), and favorable outcomes (mRS 0–2 at 90 days). A total of 39 patients were included with a median age of 69 years (IQR 61.5, 73.5); 54% were females. Hypertension was present in 76% of patients; 23% were smokers. Half of the patients had M1 occlusion (48.7%). Median preprocedural NIHSS was 11 (IQR 7.0, 19.5). Successful revascularization was achieved in 87%; median number of passes was 2 (IQR 1.0, 3.0). Median ΔNIHSS was 3.0 (IQR -1.5, 8.0). Favorable outcome was achieved in 49% (95% CI: 34%–64%), and 95% were free of complications. A total of 3 patients (7.7%) had sICH. In an exploratory analysis, posterior circulation occlusion was associated with higher mRS at 90 days (OR: 14.7, p = 0.016). Favorable discharge facility was associated with lower mRS at 90 days (OR: 0.11, p = 0.004). Our study showed comparable clinical outcomes of MT beyond 24 h compared to MT trials within 24 h in patients with favorable imaging profile, especially in anterior circulation occlusions. • Mechanical thrombectomy performed over 24 h of stroke onset showed favorable outcomes and safety. • Results were comparable to previously published large studies within 24 h. • Imaging selection was utilized based on prior published studies and recommendations. [ABSTRACT FROM AUTHOR]

Background and Purpose: Recent clinical trials investigating endovascular therapy (EVT) in the extended time window have opened new treatment paradigms for late-presenting patients with large vessel occlusion (LVO) stroke. The aim of this guideline is to provide up to date recommendations for the diagnosis, selection, and medical or endovascular treatment of patients with LVO presenting in the extended time window., Methods: The Society of Vascular & Interventional Neurology (SVIN) Guidelines and Practice Clinical Standards (GAPS) committee assembled a writing group and recruited interdisciplinary experts to review and evaluate the current literature. Recommendations were assigned by the writing group using the SVIN-GAPS Class of Recommendation/Level of Evidence algorithm and SVIN GAPS guideline format. The final guideline was approved by all members of the writing group, the GAPS committee, and the SVIN board of directors., Results: Literature review yielded three high quality randomized trials and several observational studies that have been extracted to derive the enclosed summary recommendations. In patients with LVO presenting in the 6-to-24-hour window, and with clinical imaging mismatch as defined by the DAWN and DEFUSE 3 studies, EVT is recommended. Non contrast CT can be used to evaluate infarct size as sole imaging modality for patient selection, particularly when access to CT perfusion or MRI is limited, or if their performance would incur substantial delay to treatment. In addition, several clinical questions were reviewed based on the available evidence and consensus grading., Conclusion: These guidelines provide practical recommendations based on recent evidence on the diagnosis, selection, and treatment of patients with LVO stroke presenting in the extended time window.

Introduction: The benefit of late window endovascular treatment (EVT) for anterior circulation ischemic stroke has been demonstrated using perfusion-based neuroimaging. We evaluated whether non-contrast CT (NCCT) and CT-angiogram (CTA) alone can select late-presenting patients for EVT., Methods: We performed a retrospective comparison of all patients undergoing EVT at a single comprehensive stroke center from January 2016 to April 2017. Patients planned for EVT were divided into early (<6 hours from onset) and late (≥6 hours from onset or last time seen normal) window groups. Incidence of symptomatic hemorrhagic transformations (sHTs) at 24 hours and 3-month modified Rankin scores (mRSs) were compared., Results: During the study period, 204 (82%) patients underwent EVT in the early and 44 (18%) in the late window. Median (interquartile range) NIH Stroke Scale Score was similar between groups (early: 18 [15-23] vs. late: 17 [13-21]), as were median ASPECT scores (early: 9 [8-10] vs. late: 9 [7-9]). In the late window, 42 (95%) strokes were of unknown onset. Similar proportions of sHT occurred at 24 hours (early: 12 [6%] vs. late: 4 [9%], p = 0.43). At 3 months, the proportion of patients achieving functional independence (mRS 0-2) were comparable in the early (80/192 [42%]) and late (16/41 [39%]) windows (p = 0.76)., Conclusion: NCCT- and CTA-based patient selection led to similar functional independence outcomes and low proportions of sHT in the early and late windows. In centers without access to perfusion-based neuroimaging, this pragmatic approach could be safe, particularly for strokes of unknown onset.