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Background: This study represents an additional case of a rare entity and complication of COVID-19. Purpose: To further describe COVID’s association with acute hemorrhagic leukoencephalopathy (AHL), a variant of acute disseminated encephalomyelitis. Besides, subsequent neuropsychological evaluation is described. Methods: The present case report describes clinical, laboratory, radiological, and electroencephalographic characteristics of AHL triggered by COVID-19, in addition to outcomes in the neuropsychological findings. Results: Radiologic findings of demyelinating lesions in supratentorial white matter permeated by multiple hemorrhagic foci supported the diagnostic of AHL, reinforced by clinical improvement after corticosteroid therapy. Conclusions: There are few similar cases previously reported, and this case highlights the early diagnosis and prompt treatment looking forward to better outcomes in AHL. Further studies are needed to elucidate the involved pathophysiological mechanisms.

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.

Background and purposeThe optimal selection methodology for stroke thrombectomy beyond 6 hours remains to be established.MethodsReview of a prospectively collected database of thrombectomy patients with anterior circulation strokes, adequate CT perfusion (CTP) maps, National Institute of Health Stroke Scale (NIHSS)≥10 and presenting beyond 6 hours from January 2014 to October 2018. Patients were categorised according to five selection paradigms: DAWN clinical-core mismatch (DAWN-CCM): between age-adjusted NIHSS and CTP core, DEFUSE 3 perfusion imaging mismatch (DEFUSE-3-PIM): between CTP-derived perfusion defect (Tmax >6 s lesion) and ischaemic core volumes and three non-contrast CT Alberta Stroke Program Early CT Score (ASPECTS)-based criteria: age-adjusted clinical-ASPECTS mismatch (aCAM): between age-adjusted NIHSS and ASPECTS, eloquence-adjusted clinical ASPECTS mismatch (eCAM): ASPECTS 6–10 and non-involvement of the right M6 and left M4 areas and standard clinical ASPECTS mismatch (sCAM): ASPECTS 6–10.Results310 patients underwent analysis. DEFUSE-3-PIM had the highest proportion of qualifying patients followed by sCAM, eCAM, aCAM and DAWN-CCM (93.5%, 92.6%, 90.6%, 90% and 84.5%, respectively). Patients meeting aCAM, eCAM, sCAM and DAWN-CCM criteria had higher rates of 90-day good outcome compared with their non-qualifying counterparts(43.2% vs 12%,p=0.002; 42.4% vs 17.4%, p=0.02; 42.4% vs 11.2%, p=0.009; and 43.7% vs 20.5%, p=0.007, respectively). There was no difference between patients meeting DEFUSE-3-PIM criteria versus not(40.8% vs 31.3%,p=0.45). In multivariate analysis, all selection modalities except for DEFUSE-3-PIM were independently associated with 90-day good outcome.ConclusionsASPECTS-based selection paradigms for late presenting and wake-up strokes ET have comparable proportions of qualifying patients and similar 90-day functional outcomes as DAWN-CCM and DEFUSE-3-PIM. They also might lead to better outcome discrimination. These could represent a potential alternative for centres where access to advanced imaging is limited.

BackgroundSeveral animal studies have demonstrated that mechanical thrombectomy (MT) for acute ischemic stroke (AIS) may cause vessel wall injury (VWI). However, the histological changes in human cerebral arteries following MT are difficult to determine.ObjectiveTo investigate the occurrence of VWI during MT by histological and immunohistochemical evaluation of AIS clots.MethodsAs part of the multicenter STRIP registry, 277 clots from 237 patients were analyzed using Martius Scarlett Blue stain and immunohistochemistry for CD34 (endothelial cells) and smooth muscle actin (smooth muscle cells).ResultsMT devices used were aspiration catheters (100 cases), stentriever (101 cases), and both (36 cases). VWI was found in 33/277 clots (12%). There was no significant correlation between VWI and MT device. The degree of damage varied from grade I (mild intimal damage, 24 clots), to grade II (relevant intimal and subintimal damage, 3 clots), and III (severe injury, 6 clots). VWI clots contained significantly more erythrocytes (p=0.006*) and less platelets/other (p=0.005*) than non-VWI clots suggesting soft thrombus material.Thrombolysis correlated with a lower rate of VWI (p=0.04*). VWI cases showed a significantly higher number of passes (2 [1–4] vs 1 [1–3], p=0.028*) and poorer recanalization outcome (p=0.01*) than cases without VWI.ConclusionsHistological markers of VWI were present in 12% of AIS thrombi, suggesting that VWI might be related to MT. VWI was associated with soft thrombus consistency, higher number of passes and poorer revascularization outcome. There was no significant correlation between VWI and MT device.

Background and aim Mechanical thrombectomy (MT) for large vessel occlusion often requires multiple passes to retrieve the entire thrombus load. In this multi-institutional study we sought to examine the composition of thrombus fragments retrieved with each pass during MT. Methods Patients who required multiple passes during thrombectomy were included. Histopathological evaluation of thrombus fragments retrieved from each pass was performed using Martius Scarlet Blue staining and the composition of each thrombus component including RBC, fibrin and platelet was determined using image analysis software. Results 154 patients underwent MT and 868 passes was performed which resulted in 263 thrombus fragments retrieval. The analysis of thrombus components per pass showed higher RBC, lower fibrin and platelet composition in the pass 1 and 2 when compared to pass 3 and passes 4 or more combined (P values 0.05). Similarly, when each composition of thrombus fragments retrieved in pass 3 and passes 4 or more combined were compared with each other, no significant difference was noted (P values >0.05). Conclusion Our findings confirm that thrombus fragments retrieved with each pass differed significantly in histological content. Fragments in the first passes were associated with lower fibrin and platelet composition compared to fragments retrieved in passes three and four or higher. Also, thrombus fragments retrieved after failed pass were associated with higher fibrin and platelet components.

BackgroundPatients with large vessel occlusion stroke (LVOS) and a low Alberta Stroke Program Early CT Score (ASPECTS) are often not offered endovascular therapy (ET) as they are thought to have a poor prognosis.ObjectiveTo compare the outcomes of patients with low and high ASPECTS undergoing ET based on baseline infarct volumes.MethodsReview of a prospectively collected endovascular database at a tertiary care center between September 2010 and March 2020. All patients with anterior circulation LVOS and interpretable baseline CT perfusion (CTP) were included. Subjects were divided into groups with low ASPECTS (0–5) and high ASPECTS (6-10) and subsequently into limited and large CTP-core volumes (cerebral blood flow 30% >70 cc). The primary outcome measure was the difference in rates of 90-day good outcome as defined by a modified Rankin Scale (mRS) score of 0 to 2 across groups.Results1248 patients fit the inclusion criteria. 125 patients had low ASPECTS, of whom 16 (12.8%) had a large core (LC), whereas 1123 patients presented with high ASPECTS, including 29 (2.6%) patients with a LC. In the category with a low ASPECTS, there was a trend towards lower rates of functional independence (90-day modified Rankin Scale (mRS) score 0-2) in the LC group (18.8% vs 38.9%, p=0.12), which became significant after adjusting for potential confounders in multivariable analysis (aOR=0.12, 95% CI 0.016 to 0.912, p=0.04). Likewise, LC was associated with significantly lower rates of functional independence (31% vs 51.9%, p=0.03; aOR=0.293, 95% CI 0.095 to 0.909, p=0.04) among patients with high ASPECTS.ConclusionsOutcomes may vary significantly in the same ASPECTS category depending on infarct volume. Patients with ASPECTS ≤5 but baseline infarct volumes ≤70 cc may achieve independence in nearly 40% of the cases and thus should not be excluded from treatment.

BackgroundWe retrospectively evaluated the composition of retrieved clots from ischemic stroke patients to study the association between histological composition and stroke etiologyMethodsConsecutive patients enrolled in the Stroke Thromboembolism Registry of Imaging and Pathology (STRIP) were included in this study. All patients underwent mechanical thrombectomy and retrieved clots were sent to a central core lab for processing. Histological analysis was performed using martius scarlet blue (MSB) staining, and quantification for red blood cells (RBCs), white blood cells (WBCs), fibrin and platelets was performed using Orbit Image Software. A Wilcoxon test was used for continuous variables and χ2test for categorical variables.Results1350 patients were included in this study. The overall rate of Thrombolysis In Cerebral Infarction (TICI) 2c/3 was 68%. 501 patients received tissue plasminogen activator (tPA) (37%). 267 patients (20%) had a large artery atherosclerosis (LAA) source, 662 (49%) a cardioembolic (CE) source, 301 (22%) were cryptogenic, and the remainder had other identifiable sources including hypercoagulable state or dissection. LAA thrombi had a higher mean RBC density (46±23% vs 42±22%, p=0.01) and a lower platelet density (24±18% vs 27±18%, p=0.03) than CE thrombi. Clots from dissection patients had the highest mean RBC density (50±24%) while clots from patients with a hypercoagulable state had the lowest mean RBC density (26±21%).ConclusionsOur study found statistically significant but clinically insignificant differences between clots of CE and LAA etiologies. Future studies should emphasize molecular, proteomic and immunohistochemical characteristics to determine links between clot composition and etiology.

Background As compared to single-phase CTA (sCTA), multi-phase CTA (mCTA) has been shown to more accurately estimate collateral flow in acute ischemic stroke (AIS). We sought to determine the characterization of poor collaterals across the three different phases of the mCTA. We also attempted to establish the optimal arterio-venous contrast timing parameters on sCTA that would prevent false positive reads of poor collateral status. Methods We retrospectively screened consecutive patients admitted for possible thrombectomy from February 2018 to June 2019. Only cases with intracranial internal carotid artery (ICA) or main trunk of the middle cerebral artery (MCA) occlusion and both baseline mCTA and CT Perfusion available were included. Mean Hounsfield units (HU) of torcula and torcula/patent ICA ratio were used for the arterio-venous timing analysis. Results Of the 105 patients included, 35 (34%) received IV-tPA treatment and 65 (61.9%) underwent mechanical thrombectomy. A total of 20 patients (19%) had poor collaterals on the third-phase CTA (ground-truth). The first-phase CTA often underestimated collateral score (37/105 [35%], p Conclusion A dual-phase CTA is significantly similar to a mCTA assessment of collateral score and may be applied at community-based centers. Absolute or relative thresholds for torcula opacification may be used to identify poor bolus-scan timing thus preventing erroneous assumptions of poor collaterals on sCTA.

Background and Purpose— It is unclear which factors predict acute neurological deterioration in patients with large vessel occlusion and mild symptoms. We aim to evaluate the frequency, timing, and potential predictors of acute neurological deterioration ≥4 National Institutes of Health Stroke Scale (NIHSS) points in medically managed patients with large vessel occlusion and mild presentation. Methods— Single-center retrospective study of patients with consecutive minor stroke (defined as NIHSS score of ≤5 on presentation) and large vessel occlusion from January 2014 to December 2017. Primary outcome was acute neurological deterioration ≥4 NIHSS points during the hospitalization. Secondary outcomes included ΔNIHSS (defined as discharge minus admission NIHSS score). Results— Among 1133 patients with acute minor strokes, 122 (10.6%) had visible occlusions on computed tomography angiography/magnetic resonance angiography. Twenty-four (19.7%) patients had ≥4 points deterioration on NIHSS at a median of 3.6 (1–16) hours from arrival. No clinical or radiological predictors of acute neurological deterioration ≥4 NIHSS points were observed on multivariable analysis. Rescue endovascular thrombectomy was performed more often in the ones with acute neurological deterioration ≥4 NIHSS points compared with patients with no deterioration (54% versus 0%; P P P =0.06) compared with the group with no deterioration. In patients with any degree of neurological worsening, patients who underwent rescue thrombectomy were more likely to be independent at discharge (73% versus 38%; P =0.02) and to have a favorable ΔNIHSS (−2 [−3 to 0] versus 0 [−1 to 6]; P =0.05) compared with the ones not offered rescue thrombectomy. Conclusions— Acute neurological deterioration ≥4 NIHSS points was observed in a fifth of patients with large vessel occlusion and mild symptoms, occurred very early in the hospital course, impacted functional outcomes, and could not be predicted by any of the studied clinical and radiological variables. Rescue thrombectomy was associated with improved clinical outcomes at discharge in patients with neurological deterioration.

BackgroundGiven the relative strength of prior mechanical thrombectomy (MT) data in face of the perceived poor natural history of emergent large vessel occlusion strokes, randomization to medical therapy during the recent clinical MT trials raised ethical challenges at individual and institutional levels despite overall clinical equipoise.MethodsIn a thrombectomy stroke registry, we compared treatment rates preceding and following the SWIFT-PRIME and DAWN trials. Based on effect sizes of treatment in both trials, we estimated missed opportunities due to randomization to medical therapy and estimated the societal benefit resulting from additional patients who benefited as a result of these studies.ResultsThe average monthly thrombectomy rate in the SWIFT-PRIME time window increased from 14.1±4 patients-per-month (ppm) to 23.8±6 ppm (pConclusionCompletion of recent trials resulted in observable increases in rates of thrombectomy, translating to functional benefits that rapidly offset any missed opportunities due to randomization to medical therapy arms.

BackgroundAge, neurologic deficits, core volume (CV), and clinical core or radiographic mismatch are considered in selection for endovascular therapy (ET) in anterior circulation emergent large vessel occlusion (aELVO). Semiquantitative CV estimation by Alberta Stroke Programme Early CT Score (CT ASPECTS) and quantitative CV estimation by CT perfusion (CTP) are both used in selection paradigms.ObjectiveTo compare the prognostic value of CTP CV with CT ASPECTS in aELVO.MethodsPatients in an institutional endovascular registry who had aELVO, pre-ET National Institutes of Health Stroke Scale (NIHSS) score, non-contrast CT head and CTP imaging, and prospectively collected 3-month modified Rankin Scale (mRS) score were included. Age- and NIHSS-adjusted models, including either CT ASPECTS or CTP volumes (relative cerebral blood flow ResultsWe included 508 patients with aELVO (60.8% M1 middle cerebral artery, 34% internal carotid artery, mean age 64.1±15.3 years, median baseline NIHSS score 16 (12–20), median baseline CT ASPECTS 8 (7–9), mean CV 16.7±24.8 mL). Age, pre-ET NIHSS, CT ASPECTS, CV, hypoperfusion, and perfusion imaging mismatch volumes were predictors of good outcome (mRS score 0–2). There were no differences in prognostic accuracies between reference (age, baseline NIHSS, CT ASPECTS; area under the curve (AUC)=0.76) and additional models incorporating combinations of age, NIHSS, and CTP metrics including CV, total hypoperfusion or mismatch volume (AUCs 0.72–0.75). Predicted outcomes from CT ASPECTS or CTP CV-based models had excellent agreement (R2=0.84, pConclusionsIncorporating CTP measures of core or penumbral volume, instead of CT ASPECTS, did not improve prognostication of 3-month outcomes, suggesting prognostic equivalence of CT ASPECTS and CTP CV.

Background and Purpose: The hypoperfusion intensity ratio (HIR) is a perfusion-weighted imaging parameter defined as the ratio of Tmax>10 seconds : Tmax>6 seconds volume and is believed to be reflective of collateral strength and consequently influence infarct growth. We sought to assess the utility of the HIR in predicting infarct growth in patients undergoing thrombectomy at a comprehensive stroke center (CSC). Methods: Consecutive acute ischemic stroke patients transferred to our CSC from 09/2010-11/2018 were identified and included if the following criteria were met: 1)computed tomography perfusion (CTP) imaging enabling assessment of baseline ischemic core volume and HIR 2) follow-up neuroimaging for assessment of final infarct volumes and 3)modified Thrombolysis In Cerebral Infarction scale (mTICI) 2c status or greater post-thrombectomy. Infarct growth rate (IGR) was calculated as the difference between infarct volume on follow-up imaging and the acute DWI lesion volume, divided by time from CTP to reperfusion in hours. Results: 461 patients (median age, 64 [55-75] years, median baseline NIHSS, 16 [12-21]) were eligible for this analysis. HIR poorly correlated with IGR (Spearman’s rho=0.001, p=0.89). An HIR cut-off of 0.5 was not able to discriminate ‘fast progressors’ (IGR>5 mL/hr) (AUC 0.42, sensitivity 40%, specificity 51%), or IGR at thresholds of either 2.5 or 10 mL/hr (AUC 0.44 and 0.49 respectively, with 95% confidence intervals [0.35-0.52] and [0.41-0.57], respectively). Similarly, an HIR of 0.5 only weakly distinguished ‘fast progression’ in patients reperfused beyond 120 min from imaging and patients with early CTP (last known well to CTP2 =0.13) but was predictive of ‘fast progression’ (OR 0.22, 95% CI [0.09-0.60], p=0.003, pseudo-R 2 =0.16). Conclusions: Though predictive of fast progression, the HIR is a poor discriminator of infarct growth in successfully reperfused thrombectomy patients who undergo perfusion imaging at a CSC, and thus should not be factored into treatment decision-making.

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 P P 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.

BackgroundAge and infarct volume are among the most powerful predictors of outcome after large vessel occlusion acute strokes (LVOS).ObjectiveTo study the impact of age-adjusted final infarct volume (FIV) on functional outcomes.MethodsReview of a prospectively collected thrombectomy database at a tertiary care center between September 2010 and February 2018. Consecutive patients with anterior circulation LVOS who achieved full reperfusion (modified Thrombolysis in Cerebral Infarction 3) were categorized into four age groups: (G1) Results516 patients were analyzed (G1: n=171, G2: n=130, G3: n=103, G4: n=112). Patients with poor outcome had a larger FIV in each group (pIn multivariate analysis, adjusting for confounders including age and FIV, achieving a FIV less than the age-adjusted threshold was an independent predictor of good outcome (aOR=2.72, 95% CI 1.41 to 5.24, pConclusionsAge-adjusted infarct volume represents a strong outcome discriminator beyond age and infarct volume in isolation and might help to refine patient selection and improve outcome prognostication in stroke thrombectomy.

PURPOSE Previous work has shown that quantitative EEG measures correlate with the severity of ischemic stroke. This has not been systematically validated in patients with acute ischemic stroke who have undergone mechanical thrombectomy. METHODS Data were collected from 73 patients who underwent mechanical thrombectomy and had a standard head set EEG performed during their hospital admission. For each patient, the global delta-alpha ratio (DAR) and its difference between the two hemispheres were calculated. Associations between the global and interhemispheric DAR difference with the patients' National Institutes of Health Stroke and Modified Rankin Scale scores at discharge and 3 months after thrombectomy were assessed. RESULTS The interhemispheric DAR difference correlated with the National Institutes of Health Stroke scores at discharge (Spearman R = 0.41, P = 0.0008), National Institutes of Health Stroke scores at 3 months (Spearman R = 0.60, P = 0.02) and Modified Rankin Scale scores at 3 months (Spearman R = 0.27, P = 0.01). In contrast, the global DAR did not correlate significantly with any of these clinical outcomes when evaluated as continuous variables. In a multivariate logistic regression model, both the interhemispheric DAR difference (β = 0.25, P = 0.03) and the infarct volume (β = 0.02, P = 0.03) were independently predictive of good versus poor functional outcome (Modified Rankin Scale score ≤2 vs. >2) at 3 months. CONCLUSIONS The quantitative EEG measure of interhemispheric slow relative to fast frequencies power asymmetry correlated with the discharge and 3-month National Institutes of Health Stroke and Modified Rankin Scale scores and provided added value to infarct volume in predicting functional outcome at 3 months. These data support the prognostic value of quantitative EEG in ischemic stroke patients who have undergone mechanical thrombectomy.

Introduction: CT Perfusion (CTP) has been increasingly used in patient selection for acute reperfusion therapies. Perfusion software allow for automated and faster processing using standardized approaches. We aim to compare the perfusion parameters and final infarct volume (FIV) predictability of two commercially available CTP packages (RAPID and Viz.ai). Methods: Retrospective analysis of a mechanical thrombectomy database of mechanical thrombectomy between 9/ 2018- 6/ 2019. Patients without a technically adequate baseline CTP were excluded. Ischemic core was defined as CBF Results: A total of 164 patients were included (mean age, 66±13.14 years; baseline NIHSS, 14.93±6.73; median time from CTP to reperfusion; median 86.5 IQR [61.25-111.75] min). The median baseline rCBF6: R=0.879, Tmax>8: R=0.866, Tmax>10: R=0.852. In addition, there was a highagreement rate for binary values for qualification for the DAWN (core≤21 cc: 88.9%; ≤31cc: 82.4%; ≤51cc: 89.1%), DEFUSE-3 (93%), and EXTEND (91) trials. A total of 148 patients were fully reperfused (mTICI2c-3). Their median FIV was 23.72 [11.0-78.2] cc. There was only a marginal correlation between rCBF Conclusion: The RAPID and Viz-AI software have a strong correlation in terms of the overall baseline parameters and reperfusion treatment eligibility. In fully reperfused patients, the prediction of FIV was only marginal with both softwares.

Introduction: Identification of Large Vessel Occlusion (LVO) in acute ischemic stroke (AIS) patients is critical for proper decision-making. Limited availability of trained experts and delays in LVO recognition can have a detrimental effect on outcomes. We sought to evaluate an artificial intelligence-based algorithm for LVO detection in AIS. Methods: A retrospective analysis of a prospectively-collected database of AIS patients admitted to a large volume stroke center between 2014-2018 was performed. Experienced vascular neurologists graded CTA for presence and site of LVO. Concurrently, studies were analyzed by the Viz-LVO Algorithm® version 1.4 (GA) - a convolutional neural network programmed to detect occlusions from the internal carotid artery terminus (ICA-T) to the sylvian fissure, which would include all MCA M1-segment and most M2-segment lesions. CTA readings were categorized as LVOs (ICA-T, MCA-M1, MCA-M2) versus non-LVOs/more distal occlusions. Comparisons between human and AI-based readings were done by accuracy analysis and calculating Cohen’s kappa. Results: A total of 610 CTAs were analyzed. The AI algorithm rejected 3.4% of the CTAs due to poor quality. Viz-LVO identified LVOs with an overall sensitivity of 81.3%, specificity of 87.8%, and accuracy of 83.2% (AUC 0.845 (95%CI:0.81-0.88, p Conclusion: Our study demonstrates that automated AI reading allows for fast and accurate identification of LVO strokes. Future efforts should be made to improve the detection of the more distal occlusions.

Introduction: Intracerebral hemorrhages (ICHs) accounts for approximately 15% of all strokes but carry high rates of morbidity and mortality. The location and volume of hematoma are strongly associated with outcomes. As novel treatments become established, early detection and proper volume measurement are becoming increasingly important. We aim to evaluate an artificial intelligence-based algorithm (Viz-ICH® v1.4) for ICH detection, volume measurement, and its differentiation from intraventricular hemorrhage (IVH). Methods: We performed single center retrospective analysis of non-contrast CTs (NCCTs), randomly picked from prospective cohort of acute stroke patients, with and without parenchymal ICHs, admitted to our stroke center from 02/14-03/17. Experienced stroke neurologists graded NCCTs with a semi-automated tool (OsiriX MD v.9.0.1) for presence and volume of ICH, and also presence of intraventricular hemorrhage (IVH). AI- and human-based readings were compared. Results: A total of 211 NCCTs were evaluated including 163 ICHs and 48 controls. The ICH location was basal ganglionic in 55.8%, Lobar in 23.3% and posterior fossa in 12% of the cases and 51.5 % of patients had associated IVH with mean volume 41.94 cc. The AI algorithm demonstrated high accuracy for ICH detection and volumetric measurement (Table). The maximal running time of the algorithm was under 15s. Conclusion: The presence and volume of ICHs can be accurately detected by AI Viz-ICH Algorithm, with good differentiation from IVH which will help in early triage of these patients.

Background and Purpose: Identification of patients with failing collaterals and rapid progression of infarct growth (fast progressors) is crucial when assessing patients for potential transfer from primary to comprehensive stroke centers endovascular therapy (ET). Methods: Review of a prospectively collected database of endovascular patients with anterior circulation Large vessel occlusion strokes from 09/2010-11/2018. Patients with adequate CTP maps and follow-up final infarct volume (FIV) measurements who achieved full reperfusion (mTICI 2c-3) were included.Infarct growth rate was calculated as the difference between FIV and the acute CTP core volume, divided by time from CTP to reperfusion in hours. Receiver operating characteristic analysis was used to identify the optimal infarct growth rate that better discriminated 90-day good outcome(mRS 0-2). Fast progression was defined as having an infarct growth rate above the identified threshold. Results: 461 patients qualified for the study. The optimal infarct growth rate threshold to predict good outcome was 3.9 ml/h (sensitivity 79%, specificity 47%). 286 (62%) were subsequently categorized as fast progressors. There were no differences in baseline characteristics between fast and slow progressors except for higher NIHSS(16[12-21]vs16[11-21],p=0.02), longer Last known normal to CT times (367 mins [219-679]vs 269.5[111.5-570],p Conclusions: Fast progression of infarct growth is associated with poorer clinical outcomes. ASPECTS may help triage transfers when assessing patients for ET. Larger studies are warranted.

BackgroundThe pilot use of a smartphone platform for electronic informed consent (e-Consent) in large vessel occlusion acute stroke (LVOS) trials has recently been reported. The degree of satisfaction from Legal Authorized Representatives (LARs) with regard to this process remains to be established.MethodsA single-center study evaluating the experience of LARs with the use of e-Consent in a LVOS randomized trial of an investigational drug administered within 12 hours of last known normal was carried out. A structured survey was used to evaluate the experience of the LARs with the e-consenting process.ResultsFrom February to November 2018, 60 consecutive patients were e-Consented. Of these, 53 LARs completed the survey. The median (IQR) age of the patients was 63 (53–70) years, baseline/discharge National Institutes of Health Stroke Scale score was 17 (12–20)/3(1–12), and 45% were independent at discharge. The survey was applied in person in 43% of cases and via telephone in 57%. Median LAR age was 48 (39–59) years, 64% were female, and a multi-ethnic composition was observed. Forty percent of LARs had less than tertiary level of education (high-school or less). Regarding the e-Consent, 98% of LARs reported to be ‘clear’ and 83% felt ‘very comfortable’ in signing. The overall experience was ‘excellent/good’ in 91%. Despite the positive general impression regarding the use of e-Consent, 12 LARs (22%) would have preferred paper consent. Multivariable regression indicated that lower educational status (tertiary education or less: OR 5.09, 95% CI 1.02 to 25.48; p=0.04) and lower baseline ASPECTS score (OR 0.63, 95% CI 0.41 to 0.96; p=0.03) were independently associated with preference for paper consent.Conclusionse-Consent was overall very well perceived by LARs in a randomized clinical trial of LVOS. A minority of proxies, who were more commonly less formally educated, would have preferred paper consenting.

Background and Purpose— We aimed to determine the safety and mortality after mechanical thrombectomy in patients taking vitamin K antagonists (VKAs) or direct oral anticoagulants (DOACs). Methods— In a multicenter observational cohort study, we used multiple logistic regression analysis to evaluate associations of symptomatic intracranial hemorrhage (sICH) with VKA or DOAC prescription before thrombectomy as compared with no anticoagulation. The primary outcomes were the rate of sICH and all-cause mortality at 90 days, incorporating sensitivity analysis regarding confirmed therapeutic anticoagulation. Additionally, we performed a systematic review and meta-analysis of literature on this topic. Results— Altogether, 1932 patients were included (VKA, n=222; DOAC, n=98; no anticoagulation, n=1612); median age, 74 years (interquartile range, 62–82); 49.6% women. VKA prescription was associated with increased odds for sICH and mortality (adjusted odds ratio [aOR], 2.55 [95% CI, 1.35–4.84] and 1.64 [95% CI, 1.09–2.47]) as compared with the control group, whereas no association with DOAC intake was observed (aOR, 0.98 [95% CI, 0.29–3.35] and 1.35 [95% CI, 0.72–2.53]). Sensitivity analyses considering only patients within the confirmed therapeutic anticoagulation range did not alter the findings. A study-level meta-analysis incorporating data from 7462 patients (855 VKAs, 318 DOACs, and 6289 controls) from 15 observational cohorts corroborated these observations, yielding an increased rate of sICH in VKA patients (aOR, 1.62 [95% CI, 1.22–2.17]) but not in DOAC patients (aOR, 1.03 [95% CI, 0.60–1.80]). Conclusions— Patients taking VKA have an increased risk of sICH and mortality after mechanical thrombectomy. The lower risk of sICH associated with DOAC may also be noticeable in the acute setting. Improved selection might be advisable in VKA-treated patients. Registration— URL: https://www.clinicaltrials.gov . Unique identifier: NCT03496064. Systematic Review and Meta-Analysis: CRD42019127464.

Background Little is known on the outcomes of nonagenarians treated with endovascular therapy (ET) for acute large vessel occlusion stroke. It remains unclear whether they have worse clinical outcomes than octogenarians. Methods We reviewed our prospectively collected endovascular database at a tertiary care academic institution between 09/2010–11/2018. All patients older than 80 years that underwent endovascular therapy for large vessel occlusion anterior circulation acute ischemic stroke were included and categorized into two groups: 80–89 years (octogenarians), and 90–99 years(nonagenarians). Baseline, procedural, and radiological characteristics, as well as outcome parameters were compared. Receiver operating characteristic curves were used to calculate the optimal final infarct volume (FIV) threshold to predict good outcomes in both age category. Results Fifty nonagenarians and 248 octogenarians were treated over the 8-year study period. When compared with octogenarians, nonagenarians were less often males (18% vs 34.8%, p=0.02) had lower rates of DM (12% vs 24.9%, p=0.047) and pre-procedure glucose levels (114[104–143] mg/dl vs 126[109–152], p=0.013). Other baseline characteristics and procedural parameters were comparable between groups. In terms of outcomes, rates of successful reperfusion (mTICI 2b-3) (92%% vs 91.9%, p=1.0) and any parenchymal hematomas (PH) (8.3% vs 13.3%, p=0.34) were comparable. There was a non-significant trend toward better 90-Day independent outcomes (mRS 0–2) and higher 90-day mortality favoring octogenarians (13.6% vs 25.3%, p=0.094 and 52.3% vs 38.7%, p=0.095 respectively) while ambulatory outcomes were more similar (mRS 0–3) (38.1% vs 41.9%, p=0.212). There was a non-significant shift in the overall distribution of 90-day mRS favoring octogenarians. In multivariate analysis, baseline NIHSS, ASPECTS, IV t-PA, Successful reperfusion (mTICI 2b-3) and any PH were independent predictors of a favorable shift in mRS while age category was not. A FIV ≤16.9 ml (sensitivity 67%, specificity 75%) in octogenarians and less than 12.8 mL (sensitivity 79%, specificity 80%) in nonagenarians demonstrated the greatest accuracy for identifying good outcomes. Conclusions Our study shows that there were no differences in procedural and clinical outcomes between nonagenarians and octogenarians treated with ET with more than 1/3 of nonagenarians were ambulatory at 90 days. However, advanced age seems to be associated with reduced tolerance for infarct volume. Further research is needed to optimize selection modalities in this age cohort. Disclosures M. Bouslama: None. G. Rodrigues: None. L. Pisani: None. D. Haussen: None. M. Frankel: None. R. Nogueira: 2; C; Covidien/Medtronic (SWIFT and SWIFT-PRIME Steering Committee - modest, STAR Trial Core Lab - significant), Stryker Neurovascular (Trevo-2 Trial PI - modest, DAWN Trial PI – no payment, Trevo Registry Steering Committee – no payment, Physician Advisory Board/Consultant - significant), Neuravi/Cerenovus (ARISE-II Trial Steering Committee – no payment, Physician Advisory Board - modest), Phenox (Physician Advisory Board/Consultant – modest), Genentech (Physician Advisory Board/Consultant – modest). 6; C; Penumbra (3-D Separator Trial Executive Committee – no payment).

Background and purpose Proper identification of infarct core is crucial in establishing stroke prognosis and determining whether a patient might be a candidate for endovascular therapy (ET). We sought to study those cases in which admission CTP misses a core lesion that is present on initial non-contrast CT. Methods Review of a prospectively collected database of endovascular patients with anterior circulation Large vessel occlusion strokes from January 2014-November 2018. Only patients with an e-ASPECT score Results 629 patients qualified for the study. Median age was 64 [54–75], median NIHSS was 16 [12.5–21] and median time from last-known normal to CT was 317 mins [193–578]. 161 (25.6%) presented with a TMC. On univariate analysis a TMC was associated with isolated deep MCA strokes (77.6% vs 56.6%, p Conclusions Our results show that CT perfusion might miss infarct core in 25% of the case, especially in isolated deep MCA strokes. In those cases, a CT Perfusion based paradigm to determine eligibility for ET might not be as accurate. Future studies looking into the optimal selection tools for this patient population as well as refinements of the post-processing algorithms addressing this pitfall are warranted. Disclosures M. Bouslama: None. K. Ravindran: None. G. Rodrigues: None. L. Pisani: None. D. Haussen: None. C. Barreira: None. M. Frankel: None. R. Nogueira: 2; C; Stryker Neurovascular (Trevo-2 Trial PI - modest, DAWN Trial PI – no payment, Trevo Registry Steering Committee – no payment, Physician Advisory Board/Consultant - significant), Covidien/Medtronic (SWIFT and SWIFT-PRIME Steering Committee - modest, STAR Trial Core Lab - significant), Neuravi/Cerenovus (ARISE-II Trial Steering Committee – no payment, Physician Advisory Board - modest), Phenox (Physician Advisory Board/Consultant – modest), Genentech (Physician Advisory Board/Consultant – modest). 6; C; Penumbra (3-D Separator Trial Executive Committee – no payment).

BackgroundAlthough aspiration and stent retriever thrombectomy perform similarly in proximal occlusions, no comparative series are available in distal occlusions. We aimed to compare the 3 mm Trevo Retriever against the 3MAX thromboaspiration catheter in distal arterial occlusions.MethodsA single-center retrospective review of a prospectively maintained databank for patients treated with the 3 mm Trevo stent retriever or 3MAX thromboaspiration as the upfront approach for distal occlusions (middle cerebral artery mid/distal M2/M3, anterior cerebral artery A1/A2/A3 or posterior cerebral artery P1/P2) from January 2014 to July 2018 was performed. The primary outcome was the rate of distal occlusion first-pass reperfusion (modified Thrombolysis in Cerebral Infarction (mTICI) 2b–3).ResultsOf 1100 patients treated within the study period, 137 patients/144 different arteries were treated with the 3 mm Trevo (n=92) or 3MAX device (n=52). The groups had comparable demographics and baseline characteristics. There was a higher rate of first-pass mTICI 2b–3 reperfusion (62% vs 44%; p=0.03), a trend towards a higher rate of final mTICI 2b–3 reperfusion (84% vs 69%; p=0.05), and lower use of adjuvant therapy (15% vs 31%; p=0.03) with the 3 mm Trevo compared with the 3MAX. The median number of passes (p=0.46), frequency of arterial spasm (p=1.00), rates of parenchymal hematomas (p=0.22)/subarachnoid hemorrhage (p=0.37) in the territory of the approached vessel were similar across the two groups. The 90-day rate of good outcomes (45% vs 46% in the 3 mm Trevo and 3MAX groups, respectively; p=0.84) was comparable. Multivariable regression identified baseline NIH Stroke Scale (NIHSS) score (OR 0.9; 95% CI 0.8 to 0.97; pConclusionsIn the setting of distal arterial occlusions, the 3 mm Trevo may lead to higher rates of first-pass reperfusion than direct 3MAX thromboaspiration. Lower NIHSS was found to be associated with improved reperfusion rates as observed in more proximal lesions. Further studies are warranted.

Introduction: Large vessel occlusion (LVO) may account for up to 40% of all acute ischemic strokes (AIS) and may be associated with worse patient prognosis, being responsible for 60% of dependency and more than 90% of mortality after AIS. Therefore, accurate and rapid identification of LVO and notification of specialists is critical to maximizing the benefit of proven reperfusion therapies. Recent advances in artificial intelligence technology have facilitated the development of automated LVO detection on computed tomography angiography (CTA) imaging. This study evaluated the performance of the Viz LVO algorithm in AIS patients treated at four comprehensive stroke centers. Methods: We performed a multicenter retrospective analysis of 800 CTAs from 750 AIS patients admitted to three comprehensive stroke centers between 2014 and 2018. All studies were analyzed by the latest version of Viz LVO algorithm (version 4.1.2) and the performance was compared to expert neurointerventionalists’ reports. Algorithm run-time and notification time through the Viz platform times were also recorded for each CTA. Results: The Viz LVO algorithm demonstrated 92% sensitivity, 90% specificity in the analysis of 750 CTAs. The mean and maximum run time of the algorithm were 3 minutes and 6 minutes, respectively. Furthermore, mean time to notification was 6 minutes, with a maximum time to notification of 9 minutes. Conclusions: This multicenter retrospective study demonstrates fast and accurate performance of the Viz LVO algorithm in the detection and notification of LVOs on CTAs from three comprehensive stroke centers. Using artificial intelligence, this algorithm may permit early and accurate identification of LVO stroke patients and timely notification to emergency teams, enabling quick decision-making for reperfusion therapies or transfer to specialized centers if needed. Additional studies are required to demonstrate impact on the stroke workflow that result in improved patient outcomes, operational efficiencies, and cost reductions.

Introduction: We have recently reported the pilot use of a smartphone platform for electronic informed consenting (e-Consent) in acute stroke trials. We here report the feedback provided by legal authorized representatives (LAR) after consenting for a large vessel occlusion acute ischemic stroke (LVOS) randomized clinical trial. Methods: This is a single-center prospective study investigating the criticism of LAR after the use of e-Consent for a clinical trial of neuroprotectant in LVOS within 12 hours of last normal. REDCap (Research Electronic Data Capture) is a secure, Health Insurance Portability and Accountability Act compliant, web-based platform designed for research data capture that was used to create a survey project located on a static URL that can be remotely accessed (via smartphone browser). Regardless of the geographical position of the LAR, a standard link to the URL was sent via text message to the LAR and signed. A structured survey was applied to each LAR at least 12 hours after enrollment. Results: From February-August 2018, 33 patients were enrolled in the trial. Four LARs were unavailable, 3 expired before the questionnaire could be applied, and 1 refused to participate, leaving 25 patients for the primary analysis. Mean LAR age was 49±13 years, 68% were female, 44% black/48% white, 44% had high-school education or less. All LARs reported e-Consent to be “clear”. Eighty percent felt “ very confortable” in signing an e-Consent, 16% “somewhat” and 4% “not comfortable at all”. Four (16%) LARs would prefer paper consent. The overall experience was “excellent” in 64%, “good” in 28%, and “poor” in 8%. Seventy-two percent of surveys were done via phone and 28% in person. The patient’s median baseline and discharge NIHSS was 17[IQR 12-22] and 2[1-7], and 60% had discharge modified Rankin Scale 0-2. Male gender (75% vs 6%;p=0.04) and education level less than college (100% vs 0%);p=0.03 were associated with preference of paper over e-consent, while baseline and discharge NIHSS were not. Conclusion: e-Consent was overall very well perceived by LAR in a randomized clinical trial of LVOS. A small percentage of LAR, who were more commonly male and formally less educated, preferred paper consent.

Background and Purpose: Optimal patient selection for thrombectomy in large vessel acute ischemic stroke (LVOS) remain to be established. We evaluated the performance of imaging paradigms in a cohort of endovascularly-treated LVOS. Methods: Review of a prospectively collected database of endovascular patients with anterior circulation LVOS, adequate CTP maps, and NIHSS ≥10 from January 2014-June 2018 in a clinical setting where no specific ASPECTS or CTP criteria defined treatment selection. Patients were assessed for thrombectomy eligibility by each 2 mismatch criteria: DAWN Clinical-Core Mismatch (DAWN-CCM): between age-adjusted NIHSS and CTP-derived ischemic core volume and modified Clinical-ASPECTS Mismatch (mCAM) defined as ASPECTS 6-10 and one of the following criteria: NIHSS ≥ 10 and 0-1 Cortical-ASPECTS (M1-6 area) Involvement (any age);NIHSS ≥ 10 and 0-2 Cortical-ASPECTS (M1-6 areas) Involvement (and age < 80 years old);NIHSS ≥ 20 and 0-3 Cortical-ASPECTS (M1-6 areas) Involvement (and age < 80 years old). Clinical outcomes were compared. Results: 591 patients qualified. mCAM had a higher inclusion rate as compared to the DAWN-CCM criteria (89.8%vs83.9%). The proportions of selected patients were statistically different between groups (p=0.01). Both mCAM(+) and DAWN-CCM(+) patients had higher rates of 90-day good outcomes (modified Rankin scale 0-2) compared to non-selected counterparts (53.2%vs21.3%,p Conclusion: mCAM and DAWN-CCM selection paradigms have similar inclusion rates and outcome discrimination ability. mCAM could represent a good substitute in centers where access to advanced imaging is more limited. Future studies are warranted.

Introduction: Despite being the best sources of evidence for clinical interventions, randomized controlled trials (RCTs) may raise individual ethical concerns as often times control groups are left without treatments that might be perceived as beneficial. This becomes particularly challenging when centers must randomize patients to non-treatment versus modalities that were previously considered their standard of care. We aim to assess the overall societal costs and benefits related to two recent thrombectomy RCTs. Methods: Retrospective comprehensive stroke center database analysis. The number of MT was analyzed in the year prior and the year after the SWIFT-PRIME (all cases) and DAWN (6-24h cases) trials. The societal benefit was estimated based on (1) the number of control patients in the trials, (2) the number-need-to-treat (NNT) to achieve one additional good outcome (90-day mRS 0-2), and (3) the MT growth post trial completion. Results: SWIFT PRIME was presented in February 2015. The number of MT increased from 149 the year prior to 258 in the subsequent year (12.4±3.5 vs 21.42±5.48 patients/month, p= DAWN was presented in May 2017. The number of 6-24-h MT increased from 91 the year prior to 134 in the subsequent year (7.7±3.4 vs. 11.2±3.5 patients/month, p=0.02). Our site enrolled 38 patients including 16 controls. The NNT was 3. Thus, the net result was that we missed the opportunity to provide an uncertain benefit to 5.3 individuals in order to offer a definite benefit to an additional 43 patients and definitely benefit 14.3 of them. Conclusion: A considerable benefit from thrombectomy RCTs could be measured at our center despite pre-existent aggressive treatment protocols and outreach programs confirming that individual ethical concerns should be nullified in face of equipoise. The overall societal benefit after a scientific breakthrough vastly surpasses the alleged burden of those relative few control cases.

Introduction: The standard reperfusion target for thrombectomy trials has been modified TICI (mTICI) 2b-3 (≥50% ischemic territory). Recently, full reperfusion (mTICI 2c-3) has been recommended as the ideal target. The potential added benefits of additional procedural maneuvers must be balanced against their risks, particularly when dealing with residual distal occlusions often found in mTICI 2b. It remains unknown whether more precise categorization of the mTICI2b strata leads to more reasonable treatment targets. Methods: Retrospective analysis of prospectively collected thrombectomy data spanning Jun 2011-Feb 2018. Inclusion criteria: MCA and intracranial internal carotid artery occlusions. Definitions of reperfusion: mTICI0-1: no or limiteddistal filling; mTICI2a: Results: Of 557 patients, 2.2% had mTICI0-1, 3.6% had mTICI2a, 5.9% had mTICI2b-, 30.2% mTICI2b+, and 58.2% mTICI3. The usage of intravenous tPA was lower in the mTICI2b- vs. mTICI3 (18% vs. 41%;pFigure ). Mortality rates were comparable across the mTICI2b-, mTICI 2b+, and mTICI 3 groups but higher with mTICI2a (40%;p=0.01) and mTICI0-1 (50%;p Conclusion: There is broad variation in outcomes across the different degrees of reperfusion within the mTICI 2b grade. A reperfusion target of 75%-99% (mTICI2b+) may lead comparable rates of independence versus full reperfusion.

Introduction: The hyperdense vessel sign (HDVS) on non-contrast computed tomography (NCCT) is one of the earliest findings in patients with acute ischemic stroke. Further, the HDVS has been associated with poor outcomes. Recognition of the HDVS, which indicates the presence and location of a red blood cell-rich intra-arterial thrombus, aids the diagnosis of large vessel occlusions (LVOs) and helps the triage to endovascular reperfusion. An efficient workflow to identify patients eligible for reperfusion therapy is essential to achieve the best patient outcome, and an artificial intelligence technology that can automatically detect HDVS and notify specialists may streamline this process. We present the first results using artificial intelligence to accurately identify HDVS for LVO detection. Methods: A convolutional neural network (Viz HDVS) was developed to detect hyperdense middle cerebral artery (MCA) sign of the M1 segment on NCCT. A single center retrospective analysis of NCCT in consecutive acute ischemic stroke patients from January 2014 to May 2015 with angiography-proven LVO was performed. Results of the Viz HDVS algorithm were compared to findings reported by expert neuroradiologists in the electronic medical record database, which were independently reassessed for congruence by a separate radiologist. Patients were excluded if a pre-angiography NCCT or the radiology report was unavailable for review, or if the presence of hyperdense MCA M1 sign was indeterminate. Results: A total of 223 patients were reviewed. The Viz HDVS algorithm identified hyperdense MCA M1 sign with a sensitivity of 70%, a specificity of 96%, and an AUC of 0.85 in 117 NCCT scans from acute ischemic stroke patients with LVO. The mean algorithm run time was 1 minute 30 seconds, with a maximum run time of 3 minutes. Projected mean time to specialist notification using Viz HDVS was 5 minutes. Conclusions: The novel Viz HDVS algorithm demonstrated remarkable feasibility and speed of applying artificial intelligence in the automated detection of HDVS and notification of specialists. This algorithm may aid in earlier identification and treatment of acute ischemic stroke patients with LVOs.

Background and Purpose: Isolated basal ganglia strokes are thought to have worse clinical outcomes as compared to mixed and cortical infarcts. Methods: Review of a prospectively collected database of endovascular patients with anterior circulation Large vessel occlusion strokes from January 2014-June 2018. Only patients with an ASPECT score of 6 to 9 were included. Patients were dichotomized into 2 groups according to ASPECT region involvement: (i) isolated basal ganglia and (iBG) (ii) other stroke patterns. Baseline characteristics and Clinical outcomes were compared. Results: 465 patients qualified for the study of which 324 (70%) were iBG strokes. Baseline characteristics were comparable between the 2 groups except for higher rates of hypertension (73.8%vs63.8%,p=0.03) and larger CTP core infarct (3.6 cc[0-13] vs 3[0-10.85], p Conclusions: iBG strokes carry similar procedural and clinical outcomes as other stroke patterns with a trend towards lower mortality.

Introduction: The optimal approach for distal intracranial occlusions in thrombectomy for acute ischemic stroke is unclear. We aim to compare our experience with 3mmx20 Trevo Retriever against the Penumbra 3max in small vessels. Methods: Retrospective review of a prospective thrombectomy databank for consecutive cases of use of 3mmx20 Trevo Retriever or Penumbra 3max for middle cerebral artery (MCA) mid or distal M2, M3, anterior cerebral artery (ACA A1, A2, A3) or posterior cerebral artery (PCA P1, P2) from Jan 2014-July 2018. Results: Of 1071 patients treated within the study period, 136 patients/144 different arteries underwent treatment with small devices (3mmTrevo n=92 vs 3Max n=52). There was no difference in the distal occlusion presentation: isolated distal occlusion, emboli to new or same distal territory, or multiple occlusions (p=0.11). The distribution of occlusions site was comparable (p=0.37). Demographics were comparable including age, gender, hypertension, atrial fibrillation, systolic blood pressure, last-normal to puncture. The use of intravenous alteplase was similar (p=0.47) as well as the use of balloon guide catheter (p=1.00). The approached vessel pre-clot diameter was comparable between the 3mmTrevo and 3Max groups (1.6±0.2mm vs 1.4±0.3;p=0.66), respectively. The frequency of superior vs inferior vs middle MCA division was similar (p=0.42) amongst arms. A trend for higher first-pass mTICI2b-3 reperfusion was noted in the 3mmTrevo (62% vs 44%;p=0.05) vs 3Max group. Rates of first-pass full reperfusion was comparable (42% vs 34%;p=0.38). Adjuvant therapy was used less frequently in the 3mm Trevo group (15% vs 31%;p=0.03) for comparable final mTICI3 rates (p=0.22). The number of passes (1.3±0.5 vs 1.3±0.6; p=0.9) and the frequency of arterial spasm (any spasm; p=1.00) were comparable between groups. 90-day rates of good outcomes (35/76 vs 21/43; p=0.84) were comparable amongst arms. Subarachnoid hemorrhage (p=0.37) and parenchymal hematomas (p=0.21) in the territory of approached vessel was similar. Conclusions: The 3mm Trevo may lead to enhanced rates of successful reperfusion as compared to 3Max thromboaspiration. Further studies are warranted.

Introduction: We aim to evaluate the predictors of poor neurological outcome among patients presenting with large vessel occlusion (LVO) and mild symptoms who did not undergo upfront thrombectomy. Methods: Single-center retrospective study of consecutive patients with NIHSS≤5 and LVO on CT/MR angiography within 24h from symptom onset and baseline modified rankin score (mRS)0-2 from Jan 2014-Dec 2017. Acute neurologic deterioration definition: change in NIHSS≥4 within 24h. Primary outcome: NIHSS shift ≥4 (discharge NIHSS minus admission NIHSS score). Results: Among 1156 patients with acute minor strokes, 134 (11%) met criteria. 78% underwent CTA/22% MRA, performed 4s 152[62-232]cc, Tmax>6s 57[25-108]cc, Tmax>10s 10[0-33]cc. Orthostatic challenge was performed in 28 (21%) with NIHSS worsening ≥1 in 46%. Twenty-four (18%) patients had acute neurological deterioration of NIHSS≥4 at a median of 2[1-16] hours from arrival. Median discharge NIHSS was 2[0- 4] and the NIHSS shift -1[-3- 0]. Etiology was cryptogenic in 24%, cardioembolic in 25%, and large vessel atherosclerosis in 26%. Parenchymal hematomas occurred in 7%. Overall, 22% had an unfavorable NIHSS shift ≥1, 15% NIHSS≥2, and 11% had NIHSS shift≥4. At discharge, only 62% were independent (22% mRS0, 27% mRS1, 12% mRS2). Multivariable regression indicated acute neurological deterioration (OR 7.9; 96%CI 1.4-41.9;p=0.01) and discharge mRS (OR 3.6; 96%CI 1.6-8.4;p=0.01) independently associated with NIHSS shift ≥4. Conclusion: Acute neurological worsening occurs early and predicts an NIHSS shift≥4 at discharge, which in turn is associated with worse discharge mRS. The optimal therapeutic window in LVO with mild NIHSS may be relatively narrow.

Introduction: Computed Tomography Perfusion (CTP) is frequently used in patient selection for thrombectomy. However, CTP may under or overestimate the ischemic core. Recently, the concept of ghost infarct core (GIC) admission core lesion on CTP overestimates the final infarct volume) has been described. We aim to evaluate the prevalence and impact of GIC in large vessel occlusion stroke patients that underwent mechanical thrombectomy (MT) in a large institutional database. Methods: Retrospective analysis of a prospective database for consecutive thrombectomy cases between September 2010 and February 2018. Patients with CTP and calculated final infarct volumes (FIV) were included. Individuals with posterior circulation occlusion, anterior cerebral artery, or isolated extracranial internal carotid artery were excluded. We established a threshold of 10mL to identify patients with a significant GIC. Collateral grade was rated as follows: 0 = Absent collaterals in >50% of an M2 branch territory; 1 = Diminished collaterals in > 50% of an M2 branch; 2 = Diminished collaterals in < 50% of an M2 branch; 3 = collaterals equal to the contralateral hemisphere; 4 = Increased collaterals. Results: Of 1461 patients treated within the study period, 632 were included. GIC was identified in 51 (8.1%) subjects. Patients with and without GIC had comparable demographics, NIHSS, occlusion site, and ASPECTS. Multivariable logistic regression demonstrated that better reperfusion status (mTICI 0-2a vs. 2b vs. 2c-3; OR 2.0, 95% CI [1.04-3.86], p=0.038) and worse collateral scores (OR 0.46 [0.30-0.68], p10 mL. Multivariable predictors of good outcome (modified Rankin Scale0-2 at 90-days) included GIC>10mL (OR 6.5 [95% CI 1.8-23.4], p=0.004), young age, lower NIHSS, higher NCCT ASPECTS, middle cerebral artery M2 occlusion, and better reperfusion. Conclusion: GIC is an overlooked phenomenon and may inappropriately exclude patients from thrombectomy. Although patients with GIC have worse collateral status, the presence of GIC predicts good outcome in the setting of reperfusion therapy.

Introduction: In 2015, international experts defined a standard set of patient-centered outcome measures after stroke as part of the International Consortium for Health Outcomes (ICHOM). It aims to make outcomes comparable around the world, allowing the value-based healthcare delivery. In developing countries, it is still a challenge to implement outcome measurement for stroke patients after hospital discharge, due to different structures and healthcare network characteristics. The study objective is to assess the implementation strategies of the outcome measures of ICHOM stroke in 6 Brazilian hospitals. Methods: For 1 year, we progressively implemented ICHOM outcome measurements in 6 stroke centers: 1 private, 1 public university and 4 primary stroke centers with telemedicine guidance. The data collection strategies included: in person interview, interview by phone or a link to an online form sent by e-mail. Results: 429 patients were included in the 90-day follow-up interview. In person interview was made for 80 patients (mean interview time of 5 minutes), by phone in 285 (mean interview time 8 minutes) and by e-mail in 64. There was loss of follow-up in 15% of in-person interviews, 28% on phone and 62% on e-mail. In the private hospital, where there is better data registry, only 18% of the patients were lost to follow-up, while 54% of telemedicine patients weren’t found for the interview, mainly because of lack of phone number register or even wrong number. Higher succeeded attempts occurred on evening calls compared to business hours’ calls. Conclusion: The data collection for outcome measurements of stroke patients in Brazil is still a challenge. The barrier for phone interviews was data registry error, and the correct phone number being registered allows the follow-up. Though requiring further validation, e-mail contact seems to be a good initial strategy, decreasing the need for phone calls and saving time. The phone calls are the option for patients who do not answer e-mails.