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

OBJECTIVE: We aimed to assess the impact of time to endovascular thrombectomy (EVT) on clinical outcomes in the DAWN trial, while also exploring the potential effect modification of mode of stroke onset on this relationship. METHODS: The association between every 1-h treatment delay with 90-day functional independence (modified Rankin Scale [mRS] score 0-2), symptomatic intracranial hemorrhage, and 90-day mortality was explored in the overall population and in three modes of onset subgroups (wake-up vs. witnessed vs. unwitnessed). RESULTS: Out of the 205 patients, 98 (47.8%) and 107 (52.2%) presented in the 6 to 12 hours and 12 to 24 hours time window, respectively. Considering all three modes of onset together, there was no statistically significant association between time last seen well to randomization with either functional independence or mortality at 90 days in either the endovascular thrombectomy (mRS 0-2 1-hour delay OR 1.07; 95% CI 0.93-1.24; mRS 6 OR 0.84; 95% CI 0.65-1.03) or medical management (mRS 0-2 1-hour delay OR 0.98; 95% CI 0.80-1.14; mRS 6 1-hour delay OR 0.94; 95% CI 0.79-1.09) groups. Moreover, there was no significant interaction between treatment effect and time (p = 0.439 and p = 0.421 for mRS 0-2 and 6, respectively). However, within the thrombectomy group, the models that tested the association between time last seen well to successful reperfusion (modified Treatment in Cerebral Infarction ≥2b) and 90-day functional independence showed a significant interaction with mode of presentation (p = 0.013). This appeared to be driven by a nominally positive slope for both witnessed and unwitnessed strokes versus a significantly (p = 0.018) negative slope in wake-up patients. There was no association between treatment times and symptomatic intracranial hemorrhage. INTERPRETATION: Mode of onset modifies the effect of time to reperfusion on thrombectomy outcomes, and should be considered when exploring different treatment paradigms in the extended window. ANN NEUROL 2024;96:356-364.

Comparison of CT Perfusion Software Packages for Thrombectomy Eligibility.

INTRODUCTION: Computed tomography perfusion (CTP) has played an important role in patient selection for mechanical thrombectomy (MT) in acute ischemic stroke. We aimed to investigate the agreement between perfusion parametric maps of 3 software packages - RAPID (RapidAI-IschemaView), Viz CTP(Viz.ai), and e-CTP(Brainomix) - in estimating baseline ischemic core volumes of near completely/completely reperfused patients. METHODS: We retrospectively reviewed a prospectively maintained MT database to identify patients with anterior circulation large vessel occlusion strokes (LVOS) involving the internal carotid artery or middle cerebral artery M1-segment and interpretable CTP maps treated during September 2018 to November 2019. A subset of patients with near-complete/complete reperfusion (expanded thrombolysis in cerebral infarction [eTICI] 2c-3) was used to compare the pre-procedural prediction of final infarct volumes. RESULTS: In this analysis of 242 patients with LVOS, RAPID and Viz CTP relative cerebral blood flow (rCBF) < 30% values had substantial agreement (ρ = 0.767 [95% confidence interval [CI] = 0.71-0.81]) as well as for RAPID and e-CTP (ρ = 0.668 [95% CI = 0.61-0.71]). Excellent agreement was seen for time to maximum of the residue function (Tmax ) > 6 seconds between RAPID and Viz CTP (ρ = 0.811 [95% CI = 0.76-0.84]) and substantial for RAPID and e-CTP (ρ = 0.749 [95% CI = 0.69-0.79]). Final infarct volume (FIV) prediction (n = 136) was substantial in all 3 packages (RAPID ρ = 0.744; Viz CTP ρ = 0.711; and e-CTP ρ = 0.600). CONCLUSION: Perfusion parametric maps of the RAPID, Viz CTP, and e-CTP software have substantial agreement in predicting final infarct volume in near-completely/completely reperfused patients. ANN NEUROL 2023;94:848-855.

Higher Procedural Volumes Are Associated with Faster Treatment Times, Better Functional Outcomes, and Lower Mortality in Patients Undergoing Endovascular Treatment for Acute Ischemic Stroke.

OBJECTIVE: We aimed to characterize the association of hospital procedural volumes with outcomes among acute ischemic stroke (AIS) patients undergoing endovascular therapy (EVT). METHODS: This was a retrospective, observational cohort study using data prospectively collected from January 1, 2016 to December 31, 2019 in the Get with the Guidelines-Stroke registry. Participants were derived from a cohort of 60,727 AIS patients treated with EVT within 24 hours at 626 hospitals. The primary cohort excluded patients with pretreatment National Institutes of Health Stroke Scale (NIHSS) < 6, onset-to-treatment time > 6 hours, and interhospital transfers. There were 2 secondary cohorts: (1) the EVT metrics cohort excluded patients with missing data on time from door to arterial puncture and (2) the intravenous thrombolysis (IVT) metrics cohort only included patients receiving IVT ≤4.5 hours after onset. RESULTS: The primary cohort (mean ± standard deviation age = 70.7 ± 14.8 years; 51.2% female; median [interquartile range] baseline NIHSS = 18.0 [13-22]; IVT use, 70.2%) comprised 21,209 patients across 595 hospitals. The EVT metrics cohort and IVT metrics cohort comprised 47,262 and 16,889 patients across 408 and 601 hospitals, respectively. Higher procedural volumes were significantly associated with higher odds (expressed as adjusted odds ratio [95% confidence interval] for every 10-case increase in volume) of discharge to home (1.03 [1.02-1.04]), functional independence at discharge (1.02 [1.01-1.04]), and lower rates of in-hospital mortality (0.96 [0.95-0.98]). All secondary measures were also associated with procedural volumes. INTERPRETATION: Among AIS patients primarily presenting to EVT-capable hospitals (excluding those transferred from one facility to another and those suffering in-hospital strokes), EVT at hospitals with higher procedural volumes was associated with faster treatment times, better discharge outcomes, and lower rates of in-hospital mortality. ANN NEUROL 2023.

Emergent use of ticagrelor during endovascular reperfusion in large arterial occlusions.

OBJECTIVE: Given many emerging indications for endovascular interventions in ischemic strokes, a safe and effective adjuvant antiplatelet regimen for acute revascularization has become a subject of interest. Ticagrelor is a direct oral P2Y12 inhibitor that may achieve rapid platelet suppression than standard oral therapies. We report our experience of Ticagrelor use in revascularization of acute large arterial steno-occlusive disease, describing procedural post-procedure thrombotic events, major hemorrhages, and other clinical outcomes. METHODS: This was a single-center retrospective case series of large steno-occlusive disease requiring endovascular reperfusion with emergent adjuvant Ticagrelor, defined as 30 min of the procedure from skin puncture to closure of the arteriotomy. Major outcomes investigated were thromboembolism in the target artery, and symptomatic intracranial or extracranial major hemorrhages. Additional analyses were performed with respect to timing of the administration and use of rescue GPIIb/IIIa inhibitors if any. RESULTS: 73 consecutive patients were identified, presenting with severe ischemic stroke (median NIHSS 16) of large artery origin. 67% required stent placement (45% cervical carotid, 22% intracranial artery), 9.5% angioplasty and 23% mechanical thrombectomy only. Two experienced symptomatic in-stent occlusion, and 7 experienced major hemorrhages (9.5%) including 3 fatal symptomatic intracranial hemorrhages (4.1%). Among 19 subjects (26%) who received pretreatment with Ticagrelor, there were fewer GPIIb/IIIa administration, angioplasty and stenting, without yielding benefit in functional outcome or mortality. GPIIb/IIIa was administered as rescue therapy in 45 subjects (62%), which was found associated with increased bleeding compared to patients receiving Ticagrelor only, in whom no bleeding complications were recorded (16% vs. 0%; p = 0.03). CONCLUSION: We report our findings on Ticagrelor as an adjuvant antiplatelet therapy in ischemic stroke of large arterial origin requiring emergent revascularization. Effectiveness, safety, need for additional rescue treatment, and comparison to other commonly used oral antiplatelets should be investigated in future prospective studies.

No Racial Disparity in Outcome Measures After Endovascular Treatment for Stroke in the Elderly.

BACKGROUND AND PURPOSE: Despite the lower rates of good outcomes and higher mortality in elderly patients, age does not modify the treatment effect of mechanical thrombectomy for large vessel occlusion strokes. We aimed to study whether racial background influences the outcome after mechanical thrombectomy in the elderly population. METHODS: We reviewed a prospectively maintained database of patients with acute ischemic stroke treated with mechanical thrombectomy from October 2010 through June 2020 to identify all consecutive patients with age ≥80 years and anterior circulation large vessel occlusion strokes. The patients were categorized according to their race as Black and White. Univariable and multivariable analyses were performed to define the predictors of 90-day modified Rankin Scale and mortality in the overall population and in each race separately. RESULTS: Among 2241 mechanical thrombectomy, a total of 344 patients (median [interquartile range]; age 85 [82-88] years, baseline National Institutes of Health Stroke Scale score of 19 [15-23], Alberta Stroke Program Early CT Score 9 [7-9], 69.5% females) were eligible for the analysis. White patients (n=251; 73%) had significantly lower median body mass index (25.37 versus 26.89, P=0.04) and less frequent hypertension (78.9% versus 90.3%, P=0.01) but more atrial fibrillation (64.5% versus 44.1%, P=0.001) compared with African Americans (n=93; 27%). Other clinical, imaging, and procedural characteristics were comparable between groups. The rates of symptomatic intracerebral hemorrhage, 90-day modified Rankin Scale score of 0 to 2, and mortality were comparable among both groups. On multivariable analysis, race was neither a predictor of 90-day modified Rankin Scale score of 0 to 2 (White race: odds ratio, 0.899 [95% CI, 0.409-1.974], P=0.79) nor 90-day mortality (White race: odds ratio, 1.368; [95% CI, 0.715-2.618], P=0.34). CONCLUSIONS: In elderly patients undergoing mechanical thrombectomy for acute ischemic stroke, there was no racial difference in terms of outcome.

Automated Large Artery Occlusion Detection in Stroke: A Single-Center Validation Study of an Artificial Intelligence Algorithm.

INTRODUCTION: Expediting notification of lesions in acute ischemic stroke (AIS) is critical. Limited availability of experts to assess such lesions and delays in large vessel occlusion (LVO) recognition can negatively affect outcomes. Artificial intelligence (AI) may aid LVO recognition and treatment. This study aims to evaluate the performance of an AI-based algorithm for LVO detection in AIS. METHODS: Retrospective analysis of a database of AIS patients admitted in a single center between 2014 and 2019. Vascular neurologists graded computed tomography angiographies (CTAs) for presence and site of LVO. Studies were analyzed by the Viz-LVO Algorithm® version 1.4 - neural network programmed to detect occlusions from the internal carotid artery terminus (ICA-T) to the Sylvian fissure. Comparisons between human versus AI-based readings were done by test characteristic analysis and Cohen's kappa. Primary analysis included ICA-T and/or middle cerebral artery (MCA)-M1 LVOs versus non-LVOs/more distal occlusions. Secondary analysis included MCA-M2 occlusions. RESULTS: 610 CTAs were analyzed. The AI algorithm rejected 2.5% of the CTAs due to poor quality, which were excluded from the analysis. Viz-LVO identified ICA-T and MCA-M1 LVOs with a sensitivity of 87.6%, specificity of 88.5%, and accuracy of 87.9% (AUC 0.88, 95% CI: 0.85-0.92, p < 0.001). Cohen's kappa was 0.74. In the secondary analysis, the algorithm yielded a sensitivity of 80.3%, specificity of 88.5%, and accuracy of 82.7%. The mean run time of the algorithm was 2.78 ± 0.5 min. CONCLUSION: Automated AI reading allows for fast and accurate identification of LVO strokes with timely notification to emergency teams, enabling quick decision-making for reperfusion therapies or transfer to specialized centers if needed.

Noncontrast Computed Tomography e-Stroke Infarct Volume Is Similar to RAPID Computed Tomography Perfusion in Estimating Postreperfusion Infarct Volumes.

BACKGROUND AND PURPOSE: The e-Stroke Suite software (Brainomix, Oxford, United Kingdom) is a tool designed for the automated quantification of The Alberta Stroke Program Early CT Score and ischemic core volumes on noncontrast computed tomography (NCCT). We sought to compare the prediction of postreperfusion infarct volumes and the clinical outcomes across NCCT e-Stroke software versus RAPID (IschemaView, Menlo Park, CA) computed tomography perfusion measurements. METHODS: All consecutive patients with anterior circulation large vessel occlusion stroke presenting at a tertiary care center between September 2010 and November 2018 who had available baseline infarct volumes on both NCCT e-Stroke Suite software and RAPID CTP as well as final infarct volume (FIV) measurements and achieved complete reperfusion (modified Thrombolysis in Cerebral Infarction scale 2c-3) post-thrombectomy were included. The associations between estimated baseline ischemic core volumes and FIV as well as 90-day functional outcomes were assessed. RESULTS: Four hundred seventy-nine patients met inclusion criteria. Median age was 64 years (55-75), median e-Stroke and computed tomography perfusion ischemic core volumes were 38.4 (21.8-58) and 5 (0-17.7) mL, respectively, whereas median FIV was 22.2 (9.1-56.2) mL. The correlation between e-Stroke and CTP ischemic core volumes was moderate (R=0.44; P<0.001). Similarly, moderate correlations were observed between e-Stroke software ischemic core and FIV (R=0.52; P<0.001) and CTP core and FIV (R=0.43; P<0.001). Subgroup analysis showed that e-Stroke software and CTP performance was similar in the early and late (>6 hours) treatment windows. Multivariate analysis showed that both e-Stroke software NCCT baseline ischemic core volume (adjusted odds ratio, 0.98 [95% CI, 0.97-0.99]) and RAPID CTP ischemic core volume (adjusted odds ratio, 0.98 [95% CI, 0.97-0.99]) were independently and comparably associated with good outcome (modified Rankin Scale score of 0-2) at 90 days. CONCLUSIONS: NCCT e-Stroke Suite software performed similarly to RAPID CTP in assessing postreperfusion FIV and functional outcomes for both early- and late-presenting patients. NCCT e-Stroke volumes seems to represent a viable alternative in centers where access to advanced imaging is limited. Moreover, the future development of fusion maps of NCCT and CTP ischemic core estimates may improve upon the current performance of these tools as applied in isolation.

Lack of Reperfusion Rather Than Number of Passes Defines Futility in Stroke Thrombectomy: A Matched Case-Control Study.

Background and Purpose: There is a robust relationship between the duration of ischemia and functional outcomes after mechanical thrombectomy. Higher number of mechanical thrombectomy passes strongly correlate with lower chances of favorable outcomes. Indeed, previous studies have suggested that after multiple passes the procedure may be futile. However, using uncontrolled thresholds to define thrombectomy futility might be misleading. We aim to compare the outcome of successful reperfusion after 4 to 5 passes and ≥6 passes with those of failed reperfusion. Methods: A prospectively acquired mechanical thrombectomy database from January 2012 to October 2019 was reviewed. Patients were included if they had intracranial internal carotid artery or middle cerebral artery-M1/M2 occlusions and either achieved successful reperfusion after ≥4 passes or failed reperfusion. Reperfused patients (mTICI2b-3) were divided into 2 subgroups; (1) 4 to 5 passes and (2) ≥6 passes. Each subgroup was compared with a matched group of mechanical thrombectomy failure (mTICI0-2a). The primary outcome was the shift in the degree of disability at 90-day as measured by the modified Rankin Scale. Results: A total of 273 patients were included. As compared with matched failed reperfusion patients (n=62), those reperfused after 4 to 5 passes (n=62) had a favorable shift in the overall modified Rankin Scale score distribution (adjusted odds ratio, 3.992 [95% CI, 1.807­8.512], P=0.001] and higher rates of functional independence (31% versus 8.9%, P=0.004, adjusted odds ratio; 9.860 [95% CI, 2.323­41.845], P=0.002) at 90 days. Similarly, when compared with a matched group of failed reperfusion (n=42), patients reperfused after ≥6 passes (n=42) demonstrated a favorable shift in the overall modified Rankin Scale score distribution (adjusted odds ratio, 2.640 [95% CI, 1.073­6.686], P=0.037) and had higher rates of functional independence (36.8% vs 11.1%, P=0.004, adjusted odds ratio, 5.392 [95% CI, 1.185­24.530], P=0.029) at 90 day. Rates of parenchymal hematoma type-2 and 90-day mortality were comparable in the reperfused and nonreperfused groups. Conclusions: Achieving reperfusion despite multiple passes leads to improved outcomes compared with failed procedures. Arbitrary uncontrolled thresholds for a maximum number of passes to predict futile recanalization may lead to inappropriate early termination of procedures.

Reliability of Field Assessment Stroke Triage for Emergency Destination Scale Use by Paramedics: Mobile Stroke Unit First-Year Experience.

Background and Purpose: Field Assessment Stroke Triage for Emergency Destination (FAST-ED) scale is a helpful tool to triage patients with stroke in the field. However, data on its reliability in the prehospital setting are lacking. We aim to test the reliability of FAST-ED scale when used by paramedics in a mobile stroke unit covering a metropolitan area. Methods: As part of standard operating mobile stroke unit procedures, paramedics initially evaluated patients. If the event characterized a stroke alert, the FAST-ED score was determined by the paramedic upon patient contact (in-person) and then independently by a vascular neurologist (VN) immediately after paramedic evaluation (remotely/telemedicine). This allowed testing of the interrater agreement of the FAST-ED scoring performance between on-site prehospital providers and remotely located VN. Results: Of a total of 238 patients transported in the first 15 months of the mobile stroke unit's activity, 173 were included in this study. Median age was 63 (interquartile range, 55.5­75) years and 52.6% were females. A final diagnosis of ischemic stroke was made in 71 (41%), transient ischemic attack in 26 (15%), intracranial hemorrhage in 15 (9%), whereas 61 (35%) patients were stroke mimics. The FAST-ED scores matched perfectly among paramedics and VN in 97 (56%) instances, while there was 0 to 1-point difference in 158 (91.3%), 0 to 2-point difference in 171 (98.8%), and 3 or more point difference in 2 (1.1%) patients. The intraclass correlation between VN and paramedic FAST-ED scores showed excellent reliability, intraclass correlation coefficient 0.94 (95% CI, 0.92­0.96; P<0.001). When VN recorded FAST-ED score ≥3, paramedics also scored FAST-ED≥3 in majority of instances (63/71 patients; 87.5%). A large vessel occlusion was identified in 16 (9.2%) patients; 13 occlusions were identified with a FAST-ED≥3 while 3 were missed. All of the latter patients had National Institutes of Health Stroke Scale score ≤5. Conclusions: We demonstrate excellent reliability of FAST-ED scale performed by paramedics when compared with VN, indicating that it can be accurately performed by paramedics in the prehospital setting.

Stroke Imaging Selection Modality and Endovascular Therapy Outcomes in the Early and Extended Time Windows.

BACKGROUND AND PURPOSE: Advanced imaging has been increasingly used for patient selection in endovascular stroke therapy. The impact of imaging selection modality on endovascular stroke therapy clinical outcomes in extended time window remains to be defined. We aimed to study this relationship and compare it to that noted in early-treated patients. METHODS: Patients from a prospective multicentric registry (n=2008) with occlusions involving the intracranial internal carotid or the M1- or M2-segments of the middle cerebral arteries, premorbid modified Rankin Scale score 0 to 2 and time to treatment 0 to 24 hours were categorized according to treatment times within the early (0-6 hour) or extended (6-24 hour) window as well as imaging modality with noncontrast computed tomography (NCCT)±CT angiography (CTA) or NCCT±CTA and CT perfusion (CTP). The association between imaging modality and 90-day modified Rankin Scale, analyzed in ordinal (modified Rankin Scale shift) and dichotomized (functional independence, modified Rankin Scale score 0-2) manner, was evaluated and compared within and across the extended and early windows. RESULTS: In the early window, 332 patients were selected with NCCT±CTA alone while 373 also underwent CTP. After adjusting for identifiable confounders, there were no significant differences in terms of 90-day functional disability (ordinal shift: adjusted odd ratio [aOR], 0.936 [95% CI, 0.709-1.238], P=0.644) or independence (aOR, 1.178 [95% CI, 0.833-1.666], P=0.355) across the CTP and NCCT±CTA groups. In the extended window, 67 patients were selected with NCCT±CTA alone while 180 also underwent CTP. No significant differences in 90-day functional disability (aOR, 0.983 [95% CI, 0.81-1.662], P=0.949) or independence (aOR, 0.640 [95% CI, 0.318-1.289], P=0.212) were seen across the CTP and NCCT±CTA groups. There was no interaction between the treatment time window (0-6 versus 6-24 hours) and CT selection modality (CTP versus NCCT±CTA) in terms of functional disability at 90 days (P=0.45). CONCLUSIONS: CTP acquisition was not associated with better outcomes in patients treated in the early or extended time windows. While confirmatory data is needed, our data suggests that extended window endovascular stroke therapy may remain beneficial even in the absence of advanced imaging.

Epidemiological Surveillance of the Impact of the COVID-19 Pandemic on Stroke Care Using Artificial Intelligence.

BACKGROUND AND PURPOSE: The degree to which the coronavirus disease 2019 (COVID-19) pandemic has affected systems of care, in particular, those for time-sensitive conditions such as stroke, remains poorly quantified. We sought to evaluate the impact of COVID-19 in the overall screening for acute stroke utilizing a commercial clinical artificial intelligence platform. METHODS: Data were derived from the Viz Platform, an artificial intelligence application designed to optimize the workflow of patients with acute stroke. Neuroimaging data on suspected patients with stroke across 97 hospitals in 20 US states were collected in real time and retrospectively analyzed with the number of patients undergoing imaging screening serving as a surrogate for the amount of stroke care. The main outcome measures were the number of computed tomography (CT) angiography, CT perfusion, large vessel occlusions (defined according to the automated software detection), and severe strokes on CT perfusion (defined as those with hypoperfusion volumes >70 mL) normalized as number of patients per day per hospital. Data from the prepandemic (November 4, 2019 to February 29, 2020) and pandemic (March 1 to May 10, 2020) periods were compared at national and state levels. Correlations were made between the inter-period changes in imaging screening, stroke hospitalizations, and thrombectomy procedures using state-specific sampling. RESULTS: A total of 23 223 patients were included. The incidence of large vessel occlusion on CT angiography and severe strokes on CT perfusion were 11.2% (n=2602) and 14.7% (n=1229/8328), respectively. There were significant declines in the overall number of CT angiographies (-22.8%; 1.39-1.07 patients/day per hospital, P<0.001) and CT perfusion (-26.1%; 0.50-0.37 patients/day per hospital, P<0.001) as well as in the incidence of large vessel occlusion (-17.1%; 0.15-0.13 patients/day per hospital, P<0.001) and severe strokes on CT perfusion (-16.7%; 0.12-0.10 patients/day per hospital, P<0.005). The sampled cohort showed similar declines in the rates of large vessel occlusions versus thrombectomy (18.8% versus 19.5%, P=0.9) and comprehensive stroke center hospitalizations (18.8% versus 11.0%, P=0.4). CONCLUSIONS: A significant decline in stroke imaging screening has occurred during the COVID-19 pandemic. This analysis underscores the broader application of artificial intelligence neuroimaging platforms for the real-time monitoring of stroke systems of care.

Thrombectomy 6 to 24 Hours after Stroke with a Mismatch between Deficit and Infarct.

BACKGROUND: The effect of endovascular thrombectomy that is performed more than 6 hours after the onset of ischemic stroke is uncertain. Patients with a clinical deficit that is disproportionately severe relative to the infarct volume may benefit from late thrombectomy. METHODS: We enrolled patients with occlusion of the intracranial internal carotid artery or proximal middle cerebral artery who had last been known to be well 6 to 24 hours earlier and who had a mismatch between the severity of the clinical deficit and the infarct volume, with mismatch criteria defined according to age (<80 years or ≥80 years). Patients were randomly assigned to thrombectomy plus standard care (the thrombectomy group) or to standard care alone (the control group). The coprimary end points were the mean score for disability on the utility-weighted modified Rankin scale (which ranges from 0 [death] to 10 [no symptoms or disability]) and the rate of functional independence (a score of 0, 1, or 2 on the modified Rankin scale, which ranges from 0 to 6, with higher scores indicating more severe disability) at 90 days. RESULTS: A total of 206 patients were enrolled; 107 were assigned to the thrombectomy group and 99 to the control group. At 31 months, enrollment in the trial was stopped because of the results of a prespecified interim analysis. The mean score on the utility-weighted modified Rankin scale at 90 days was 5.5 in the thrombectomy group as compared with 3.4 in the control group (adjusted difference [Bayesian analysis], 2.0 points; 95% credible interval, 1.1 to 3.0; posterior probability of superiority, >0.999), and the rate of functional independence at 90 days was 49% in the thrombectomy group as compared with 13% in the control group (adjusted difference, 33 percentage points; 95% credible interval, 24 to 44; posterior probability of superiority, >0.999). The rate of symptomatic intracranial hemorrhage did not differ significantly between the two groups (6% in the thrombectomy group and 3% in the control group, P=0.50), nor did 90-day mortality (19% and 18%, respectively; P=1.00). CONCLUSIONS: Among patients with acute stroke who had last been known to be well 6 to 24 hours earlier and who had a mismatch between clinical deficit and infarct, outcomes for disability at 90 days were better with thrombectomy plus standard care than with standard care alone. (Funded by Stryker Neurovascular; DAWN ClinicalTrials.gov number, NCT02142283 .).

Safety of Ticagrelor in Moderate and Severe Acute Ischemic Stroke: A Single-Center Retrospective Review.

OBJECTIVES: Ticagrelor may be superior to aspirin after minor ischemic stroke or TIA, particularly in patients with symptomatic atherosclerotic disease. However, there may be an increased risk of intracerebral hemorrhage in patients with moderate to severe ischemic stroke, and ticagrelor has not been studied in this patient population. Therefore, we sought to evaluate the safety of ticagrelor after moderate or severe ischemic stroke. MATERIALS AND METHODS: Retrospective chart review of all patients admitted with acute ischemic stroke and NIHSS 6 or greater who were discharged on ticagrelor between January 2016 and December 2019. Patients who underwent angioplasty, stenting or carotid revascularization during the hospitalization were excluded. RESULTS: Of 183 patients discharged on ticagrelor, 61 patients were included. Median age was 61 (IQR 52-68); 33 (54%) patients were men. Median NIHSS was 11 (IQR 8-15). Fourteen (23%) patients received IV alteplase and 35 (57%) patients received mechanical thrombectomy. Stroke mechanism was large artery atherosclerosis in 53 (87%) of patients, of which 40 (71%) were deemed intracranial atherosclerosis. Final infarct volume was greater than 10 mL in 32 (52%) patients. Follow-up information was available for 53 (87%) patients; median length of follow-up was 3 (IQR 2-6) months. Six (10%) patients experienced recurrent ischemic stroke. No patients experienced symptomatic intracerebral hemorrhage after initiation of ticagrelor. One (2%) patient experienced major bleeding. CONCLUSIONS: This study provides preliminary evidence supporting the potential safety of ticagrelor following moderate or severe acute ischemic stroke. These findings support the need for future prospective studies.

Site Experience and Outcomes in the Trevo Acute Ischemic Stroke (TRACK) Multicenter Registry.

Background and Purpose- It remains unclear how experience influences outcomes after the advent of stent retriever technology. We studied the relationship between site experience and outcomes in the Trevo Acute Ischemic Stroke multicenter registry. Methods- The 24 sites that enrolled patients in the Trevo Acute Ischemic Stroke registry were trichotomized into low-volume (<2 cases/month), medium-volume (2-4 cases/month), and high-volume centers (>4 cases/month). Baseline features, imaging, and clinical outcomes were compared across the 3 volume strata. A multivariable analysis was performed to assess whether outcomes were influenced by site volumes. Results- A total of 624 patients were included and distributed as low- (n=188 patients, 30.1%), medium- (n=175, 28.1%), and high-volume (n=261, 41.8%) centers. There were no significant differences in terms of age (mean, 66±16 versus 67±14 versus 65±15; P=0.2), baseline National Institutes of Health Stroke Scale (mean, 17.6±6.5 versus 16.8±6.5 versus 17.6±6.9; P=0.43), or occlusion site across the 3 groups. Median (interquartile range) times from stroke onset to groin puncture were 266 (181.8-442.5), 239 (175-389), and 336.5 (221.3-466.5) minutes in low-, medium-, and high-volume centers, respectively (P=0.004). Higher efficiency and better outcomes were seen in higher volume sites as demonstrated by shorter procedural times (median, 97 versus 67 versus 69 minutes; P<0.001), higher balloon guide catheter use (40% versus 36% versus 59%; P≤0.0001), and higher rates of good outcome (90-day modified Rankin Scale [mRS], ≤2; 39% versus 50% versus 53.4%; P=0.02). There were no appreciable differences in symptomatic intracranial hemorrhage or 90-day mortality. After adjustments in the multivariable analysis, there were significantly higher chances of achieving a good outcome in high- versus low-volume (odds ratio, 1.67; 95% CI, 1.03-2.7; P=0.04) and medium- versus low-volume (odds ratio, 1.75; 95% CI, 1.1-2.9; P=0.03) centers, but there were no significant differences between high- and medium-volume centers (P=0.86). Conclusions- Stroke center volumes significantly influence efficiency and outcomes in mechanical thrombectomy.

Carotid Webs in Cryptogenic Ischemic Strokes: A Matched Case-Control Study.

BACKGROUND: Young individuals with symptomatic carotid webs may be predisposed to ischemic strokes. However, evidence remains scarce. This investigation reports the frequency of carotid webs among patients with cryptogenic strokes compared to a control group. METHODS: Consecutive cryptogenic ischemic strokes and trauma patients were identified. Additional inclusion criteria required age 18-60 years and availability of head/neck computed tomography (CT) angiography. CT angiogram (CTA) neck images were evaluated independently by 2 fellowshiptrained specialists. A carotid web was defined by a shelf-like, linear filling defect in the posterior internal carotid artery bulb. RESULTS: Of 1877 patients presenting with ischemic strokes in 2015-2017, 165 were diagnosed with cryptogenic strokes, 51 of whom met the inclusion criteria of age and CTA availability. Fifty one trauma cases were matched for age and sex. After imaging analysis, 13 carotid webs (25%) were identified in the 51 cryptogenic stroke group versus 0 (0%; P < .001) in trauma subjects. Thirty-nine of the 51 cryptogenic ischemic stroke patients were found with carotid anterior distribution infarcts, of which 9 (23%) were found with ipsilateral carotid webs. There were more proximal large vessel occlusions in the cryptogenic patients with carotid webs, compared to those without (P = .04). All carotid webs led to less than 30% degree of stenosis. CONCLUSIONS: Carotid webs were found at a significantly higher frequency in patients with cryptogenic ischemic strokes compared to controls, indicating a potentially thrombogenic nature of these lesions in young patients. Additionally, intracranial large vessel occlusions were more common in patients with symptomatic carotid webs, presenting with ipsilateral strokes.

Beyond Large Vessel Occlusion Strokes: Distal Occlusion Thrombectomy.

BACKGROUND AND PURPOSE: Endovascular therapy is the standard of care for the treatment of proximal large vessel occlusion strokes. Its safety and efficacy in the treatment of distal intracranial occlusions has not been well studied. METHODS: The data that support the findings of this study are available from the corresponding author on reasonable request. Retrospective review of a prospectively collected endovascular database (2010-2015, n=949) for all patients with distal intracranial occlusions treated endovascularly. Distal occlusions were defined as any segment of the anterior cerebral artery (ACA), posterior cerebral artery, or occlusion at or distal to the middle cerebral artery (MCA)-M3 opercular segment. RESULTS: Distal occlusions were treated in 69 patients. The mean age was 66.7±15.8 and 57% were male. Patients (29 [42%]) received intravenous tPA (tissue-type plasminogen activator). The median preprocedure National Institutes of Health Stroke Scale score was 18 (interquartile range, 13-23). The distal occlusion was the primary treatment location in 45 patients, in 23 patients the distal occlusion was treated as a rescue strategy after successful treatment of a proximal large vessel occlusion strokes, and 1 patient had both primary and rescue treatment. The locations of the primary cases were MCA-M3 (n=21), ACA alone (n=8), ACA with a concomitant MCA-M1 or MCA-M2 (n=10), ACA with a concomitant MCA-M3 (n=3), and posterior cerebral artery (n=3). The locations of the rescue cases were MCA-M3 (n=11), ACA (n=7), posterior cerebral artery (n=4), and both MCA-M3 and ACA (n=1). There was a single patient with primary ACA and MCA-M2 occlusions treated, who then had a rescue MCA-M3 thrombectomy addressed after initial reperfusion. The most common treatment modalities used were stent-retrievers (n=37, 54%), intra-arterial tPA (n=36, 52%), and thromboaspiration (n=31, 45%). Near complete or complete reperfusion of the distal territory (modified Treatment In Cerebral Ischemia [mTICI] 2b-3) was achieved in 57 cases (83%). Three parenchymal hematomas (4%) occurred in the territory of the treated distal occlusion with 2 of these patients also receiving intravenous tPA. At 90 days, 21 patients (30%) had a modified Rankin Scale score of 0 to 2 and 14 (20%) had died. CONCLUSIONS: Distal intracranial occlusions can be treated safely and successfully with endovascular therapy. These results need to be corroborated by larger prospective controlled studies.

The impact of IV alteplase on long-term patient survival: The Georgia Coverdell acute stroke registry's experience.

INTRODUCTION: Intravenous alteplase reduces disability and improves functionality among acute ischemic stroke patients. Two decades after its approval, only a small fraction of patients get the treatment, and demonstrating its impact on mortality may make a strong case for its wider use. This study assessed the impact of thrombolytic treatment by alteplase on 1-year mortality and readmission among acute ischemic stroke patients. METHOD: The 2008-2013 Georgia Coverdell Acute Stroke Registry data were linked with the 2008-2013 hospital discharge and the 2008-2014 death data in Georgia. Multiple imputation was applied; a propensity score measuring the probability of receiving intravenous alteplase was calculated and used for matching. A conditional logistic regression was applied to compare 1-year mortality and readmission among propensity score matched pairs. RESULTS: Overall, 20.3% of 9620 acute ischemic stroke patients died and 22.4% were readmitted in one year. The multivariable regression result showed that patients who did not receive IV alteplase had a 1.49 (95%CI: 1.09-2.04; p-value=0.01) times higher odds of dying at one year than those who were treated with the thrombolytic agent. Among patients discharged home, no statistically significant difference was documented in the odds of being readmitted at least once within 365days post-stroke discharge. DISCUSSION AND CONCLUSION: After accounting for patient differences and missing value, intravenous alteplase is associated with reduction in long-term mortality. The results of this study suggest that patients who are identified as eligible for intravenous alteplase need to be offered the treatment.

Predictors of Good Outcome After Endovascular Therapy for Vertebrobasilar Occlusion Stroke.

BACKGROUND AND PURPOSE: Endovascular therapy is increasingly used in acute ischemic stroke treatment and is now considered the gold standard approach for selected patient populations. Prior studies have demonstrated that eventual patient outcomes depend on both patient-specific factors and procedural considerations. However, these factors remain unclear for acute basilar artery occlusion stroke. We sought to determine prognostic factors of good outcome in acute posterior circulation large vessel occlusion strokes treated with endovascular therapy. METHODS: We reviewed our prospectively collected endovascular databases at 2 US tertiary care academic institutions for patients with acute posterior circulation strokes from September 2005 to September 2015 who had 3-month modified Rankin Scale documented. Baseline characteristics, procedural data, and outcomes were evaluated. A good outcome was defined as a 90-day modified Rankin Scale score of 0 to 2. The association between clinical and procedural parameters and functional outcome was assessed. RESULTS: A total of 214 patients qualified for the study. Smoking status, creatinine levels, baseline National Institutes of Health Stroke Scale score, anesthesia modality (conscious sedation versus general anesthesia), procedural length, and reperfusion status were significantly associated with good outcomes in the univariate analysis. Multivariate logistic regression indicated that only smoking (odds ratio=2.61; 95% confidence interval, 1.23-5.56; P=0.013), low baseline National Institutes of Health Stroke Scale score (odds ratio=1.09; 95% confidence interval, 1.04-1.13; P<0.0001), and successful reperfusion status (odds ratio=10.80; 95% confidence interval, 1.36-85.96; P=0.025) were associated with good outcome. CONCLUSIONS: In our retrospective case series, only smoking, low baseline National Institutes of Health Stroke Scale score, and successful reperfusion status were associated with good outcome in patients with posterior circulation stroke treated with endovascular therapy.

Cervical Carotid Pseudo-Occlusions and False Dissections: Intracranial Occlusions Masquerading as Extracranial Occlusions.

BACKGROUND AND PURPOSE: Pseudo-occlusion (PO) of the cervical internal carotid artery (ICA) refers to an isolated occlusion of the intracranial ICA that appears as an extracranial ICA occlusion on computed tomography angiography (CTA) or digital subtraction angiography because of blockage of distal contrast penetration by a stagnant column of unopacified blood. We aim to better characterize this poorly recognized entity. METHODS: Retrospective review of an endovascular database (2010-2015; n=898). Only patients with isolated intracranial ICA occlusions as confirmed by angiographic exploration were included. CTA and digital subtraction angiography images were categorized according to their apparent site of occlusion as (1) extracranial ICA PO or (2) discernible intracranial ICA occlusion. RESULTS: Cervical ICA PO occurred in 21/46 (46%) patients on CTA (17 proximal cervical; 4 midcervical). Fifteen (71%) of these patients also had PO on digital subtraction angiography. A flame-shaped PO mimicking a carotid dissection was seen in 7 (33%) patients on CTA and in 6 (29%) patients on digital subtraction angiography. Patients with and without CTA PO had similar age (64.8±17.1 versus 60.2±15.7 years; P=0.35), sex (male, 47% versus 52%; P=1.00), and intravenous tissue-type plasminogen activator use (38% versus 40%; P=1.00). The rates of modified Treatment In Cerebral Ischemia 2b-3 reperfusion were 71.4% in the PO versus 100% in the non-PO cohorts (P<0.01). The rates of parenchymal hematoma, 90-day modified Rankin Scale score 0-2, and 90-day mortality were 4.8% versus 8% (P=0.66), 40% versus 66.7% (P=0.12), and 25% versus 21% (P=0.77) in PO versus non-PO patients, respectively. Multivariate analysis indicated that PO patients had lower chances of modified Treatment In Cerebral Ischemia 3 reperfusion (odds ratio 0.14; 95% confidence interval 0.02-0.70; P=0.01). CONCLUSIONS: Cervical ICA PO is a relatively common entity and may be associated with decreased reperfusion rates.

Computed Tomographic Perfusion Selection and Clinical Outcomes After Endovascular Therapy in Large Vessel Occlusion Stroke.

BACKGROUND AND PURPOSE: Different imaging paradigms have been used to select patients for endovascular therapy in stroke. We sought to determine whether computed tomographic perfusion (CTP) selection improves endovascular therapy outcomes compared with noncontrast computed tomography alone. METHODS: Review of a prospectively collected registry of anterior circulation stroke patients undergoing stent-retriever thrombectomy at a tertiary care center between September 2010 and March 2016. Patients undergoing CTP were compared with those with noncontrast computed tomography alone. The primary outcome was the shift in the 90-day modified Rankin scale (mRS). RESULTS: A total of 602 patients were included. CTP-selected patients (n=365, 61%) were younger (P=0.02) and had fewer comorbidities. CTP selection (n=365, 61%) was associated with a favorable 90-day mRS shift (adjusted odds ratio [aOR]=1.49; 95% confidence interval [CI], 1.06-2.09; P=0.02), higher rates of good outcomes (90-day mRS score 0-2: 52.9% versus 40.4%; P=0.005), modified Thrombolysis in Cerebral Infarction-3 reperfusion (54.8% versus 40.1%; P<0.001), smaller final infarct volumes (24.7 mL [9.8-63.1 mL] versus 34.6 mL [13.1-88 mL]; P=0.017), and lower mortality (16.6% versus 26.8%; P=0.005). When matched on age, National Institutes of Health Stroke Scale (NIHSS) score, and glucose (n=424), CTP remained associated with a favorable 90-day mRS shift (P=0.016), lower mortality (P=0.02), and higher rates of reperfusion (P<0.001). CTP better predicted functional outcomes in patients presenting after 6 hours (as assessed by comparison of logistic regression models: Akaike information criterion: 199.35 versus 287.49 and Bayesian information criterion: 196.71 versus 283.27) and those with an Alberta Stroke Program Early Computed Tomography Score ≤7 (Akaike information criterion: 216.69 versus 334.96 and Bayesian information criterion: 213.6 versus 329.94). CONCLUSIONS: CTP selection is associated with a favorable mRS shift in patients undergoing stent-retriever thrombectomy. Future prospective studies are warranted.