Alberta Stroke Program Early Computed Research Articles

Outcomes of Mechanical Thrombectomy for Patients With Stroke Presenting With Low Alberta Stroke Program Early Computed Tomography Score in Early and Late Time Windows.

This study aimed to compare outcomes of low Alberta Stroke Program Early Computed Tomography Score (ASPECTS) patients with stroke who underwent mechanical thrombectomy (MT) within 6 hours or 6 to 24 hours after stroke onset. A retrospective cohort study was conducted using data from a large multicenter international registry from 2013 to 2023. Patients with low ASPECTS (2-5) who underwent MT for anterior circulation intracranial large vessel occlusion were included. A propensity matching analysis was conducted for patients presented in the early (<6 hours) vs late (6-24 hours) time window after symptom onset or last known normal. Among the 10 229 patients who underwent MT, 274 met the inclusion criteria. 122 (44.5%) patients were treated in the late window. Early window patients were older (median age, 74 years [IQR, 63-80] vs 66.5 years [IQR, 54-77]; P < .001), had lower proportion of female patients (40.1% vs 54.1%; P = .029), higher median admission National Institutes of Health Stroke Scale score (20 [IQR, 16-24] vs 19 [IQR, 14-22]; P = .004), and a higher prevalence of atrial fibrillation (46.1% vs 27.3; P = .002). Propensity matching yielded a well-matched cohort of 84 patients in each group. Comparing the matched cohorts showed there was no significant difference in acceptable outcomes at 90 days between the 2 groups (odds ratio = 0.90 [95% CI = 0.47-1.71]; P = .70). However, the rate of symptomatic ICH was significantly higher in the early window group compared with the late window group (odds ratio = 2.44 [95% CI = 1.06-6.02]; P = .04). Among patients with anterior circulation large vessel occlusion and low ASPECTS, MT seems to provide a similar benefit to functional outcome for patients presenting <6 hours or 6 to 24 hours after onset.

Endovascular Therapy in Large Core Ischemic Strokes: Real-World Indian Experience

Abstract Background: Large core acute ischemic strokes have predominantly been excluded from endovascular therapy (EVT) studies due to perceived higher risks of hemorrhage and poorer functional outcomes. However, recent randomized controlled trials (RCTs) indicate that EVT for large vessel occlusion (LVO) strokes improves functional outcomes compared to medical management alone, despite higher hemorrhagic transformation rates, with no corresponding increase in symptomatic intracerebral hemorrhage (sICH) rates. The real-world outcomes of this intervention in Indian patients remain underexplored. Objectives: To evaluate the real-world outcomes of EVT for large core acute ischemic strokes with LVO in an Indian population. Methods: We conducted a single-center, retrospective observational study using a 7 years prospective database of EVT in anterior circulation stroke patients. Patients with Alberta Stroke Program Early Computed Tomography Score (ASPECTS) of 3–5 were included. Clinical and radiologic data were analyzed, with the primary endpoint being 90-day modified Rankin scale (mRS) scores. Safety outcomes included rates of sICH and mortality. Descriptive statistical analysis was done using Microsoft Excel. Results: The study included 25 patients who met the inclusion criteria. Mean age of patients was 52.9 ± 14.3 years, and there were 13 (52%) males. Median ASPECTS was 5 (interquartile range 4–5). Successful recanalization, classified by modified Thrombolysis in Cerebral Infarction score, was 92%. Good functional recovery, that is, 90-day mRS 0–3, was achieved in nine (36%) patients. Safety outcomes: sICH was seen in four (16%) and mortality was reported in nine (36%) patients. Conclusions: Our results reaffirm findings from RCTs, provide updated real-world evidence, and suggest that EVT is a viable option to be considered in selected patients with large core ischemic infarcts.

Trial of Thrombectomy for Stroke with a Large Infarct of Unrestricted Size

BackgroundThe use of thrombectomy in patients with acute stroke and a large infarct of unrestricted size has not been well studied.MethodsWe assigned, in a 1:1 ratio, patients with proximal cerebral vessel occlusion in the anterior circulation and a large infarct (as defined by an Alberta Stroke Program Early Computed Tomographic Score of ≤5; values range from 0 to 10) detected on magnetic resonance imaging or computed tomography within 6.5 hours after symptom onset to undergo endovascular thrombectomy and receive medical care (thrombectomy group) or to receive medical care alone (control group). The primary outcome was the score on the modified Rankin scale at 90 days (scores range from 0 to 6, with higher scores indicating greater disability). The primary safety outcome was death from any cause at 90 days, and an ancillary safety outcome was symptomatic intracerebral hemorrhage.ResultsA total of 333 patients were assigned to either the thrombectomy group (166 patients) or the control group (167 patients); 9 were excluded from the analysis because of consent withdrawal or legal reasons. The trial was stopped early because results of similar trials favored thrombectomy. Approximately 35% of the patients received thrombolysis therapy. The median modified Rankin scale score at 90 days was 4 in the thrombectomy group and 6 in the control group (generalized odds ratio, 1.63; 95% confidence interval [CI], 1.29 to 2.06; P<0.001). Death from any cause at 90 days occurred in 36.1% of the patients in the thrombectomy group and in 55.5% of those in the control group (adjusted relative risk, 0.65; 95% CI, 0.50 to 0.84), and the percentage of patients with symptomatic intracerebral hemorrhage was 9.6% and 5.7%, respectively (adjusted relative risk, 1.73; 95% CI, 0.78 to 4.68). Eleven procedure-related complications occurred in the thrombectomy group.ConclusionsIn patients with acute stroke and a large infarct of unrestricted size, thrombectomy plus medical care resulted in better functional outcomes and lower mortality than medical care alone but led to a higher incidence of symptomatic intracerebral hemorrhage. (Funded by Montpellier University Hospital; LASTE ClinicalTrials.gov number, NCT03811769.)

Endovascular Therapy and Outcomes Among Patients With Very Large Ischemic Core Stroke

The association of endovascular therapy (EVT) with outcomes is unclear for patients with very low Alberta Stroke Program Early Computed Tomography Score (ASPECTS) within 24 hours of stroke onset. To explore the association of EVT with functional and safety outcomes among patients with ASPECTS of 0 to 2 scored with noncontrast computed tomography. This cohort study used data from an ongoing, prospective, observational, nationwide registry including all patients treated at 38 stroke centers in China with an occlusion in the internal carotid artery or M1 or M2 segment of the middle cerebral artery within 24 hours of witnessed symptom onset. Patients with ASPECTS of 0 to 2 between November 1, 2021, and February 8, 2023, were included in analysis. Data were analyzed October to November 2023. EVT vs standard medical treatment (SMT). The primary outcome was favorable functional outcome, defined as modified Rankin Scale score (mRS) of 0 to 3, at 90 days. Safety outcomes included symptomatic intracerebral hemorrhage (sICH) within 48 hours and mortality at 90 days. A total of 245 patients (median [IQR] age, 71 [63-78] years; 118 [48%] women) with ASPECTS of 0 to 2 were included, of whom 111 patients (45.1%) received SMT and 135 patients (54.9%) received EVT. The EVT group had significantly greater odds of favorable functional outcome at 90 days than the SMT group (30 patients [22.2%] vs 11 patients [9.9%]; P = .01; adjusted odds ratio [aOR], 3.07 [95% CI, 1.29-7.31]; P = .01). Patients in the EVT group, compared with the SMT group, had significantly greater odds of any ICH (56 patients [41.5%] vs 16 patients [11.4%]; P < .001; aOR, 4.27 [95% CI, 2.19-8.35]; P < .001) and sICH (24 patients [17.8%] vs 1 patient [0.9%]; P < .001; aOR, 23.07 [95% CI, 2.99-177.79]; P = .003) within 48 hours. There were no differences between groups for 90-day mortality (80 patients [59.3%] vs 59 patients [53.2%]; P = .34; aOR, 1.38 [95% CI, 0.77-2.47]; P = .28). The results remained robust in the propensity score-matched analysis. In this cohort study of patients with very low ASPECTS based on NCCT within 24 hours of stroke onset, those treated with EVT had higher odds of a favorable functional outcome compared with those who received SMT. Randomized clinical trials are needed to assess these findings.

Automatic assessment of DWI-ASPECTS for acute ischemic stroke based on deep learning.

Alberta Stroke Program Early Computed Tomography Score (ASPECTS) is a standardized semi-quantitative method for early ischemic changes in acute ischemic stroke. However, ASPECTS is still affected by expert experience and inconsistent results between readers in clinical. This study aims to propose an automatic ASPECTS scoring model based on diffusion-weighted imaging (DWI) mode to help clinicians make accurate treatment plans. Eighty-two patients with stroke were included in the study. First, we designed a new deep learning network for segmenting ASPECTS scoring brain regions. The network is improved based on U-net, which integrates multiple modules. Second, we proposed using hybrid classifiers to classify brain regions. For brain regions with larger areas, we used brain grayscale comparison algorithm to train machine learning classifiers, while using hybrid feature training for brain regions with smaller areas. The average DICE coefficient of the segmented hindbrain area can reach 0.864. With the proposed hybrid classifier, our method performs significantly on both region-level ASPECTS and dichotomous ASPECTS. The sensitivity and accuracy on the test set are 95.51% and 93.43%, respectively. For dichotomous ASPECTS, the intraclass correlation coefficient (ICC) between our automated ASPECTS score and the expert reading was 0.87. This study proposed an automated model for ASPECTS scoring of patients with acute ischemic stroke based on DWI images. Experimental results show that the method of segmentation first and then classification is feasible. Our method has the potential to assist physicians in the Alberta Stroke Program with early CT scoring and clinical stroke diagnosis.

Thrombectomy in Patients With Ischemic Stroke Without Salvageable Tissue on CT Perfusion.

Computed tomography perfusion (CTP) imaging is regularly used to guide patient selection for mechanical thrombectomy (MT). However, the effect of MT in patients without salvageable tissue on CTP has not been investigated. The purpose of this study was to assess the effect of MT in patients with stroke without perfusion mismatch profiles. This observational study analyzed patients with ischemic stroke consecutively treated between March 1, 2015, and January 31, 2022, triaged by multimodal-computed tomography undergoing MT. CTP lesion-core mismatch profiles were defined using a mismatch volume/ratio of ≥10 mL/1.2, respectively. The primary end point was the rate of functional independence at 90 days, defined as the modified Rankin Scale score of 0 to 2. Recanalization was evaluated with the modified Thrombolysis in Cerebral Infarction scale. The effect of baseline variables on functional outcome was assessed using multivariable logistic regression analysis. Outcomes of patients with and without CTP-mismatch profiles were compared using 1:1 propensity score matching. Of 724 patients who met the inclusion criteria of this retrospective observational study, 110 (15%) patients had no CTP mismatch and were analyzed. The median age was 74 (interquartile range, 62-80) years and 53% were women. Successful recanalization (modified Thrombolysis in Cerebral Infarction score, ≥2b) was achieved in 66% (73) and associated with functional independence at 90 days (adjusted odds ratio, 7.33 [95% CI, 1.22-43.70]; P=0.03). A significant interaction was observed between recanalization and age, as well as the extent of infarction, indicating MT to be most effective in patients <70 years and with a baseline Alberta Stroke Program Early Computed Tomography Score range between 3 and 7. These findings remained stable after propensity score matching, analyzing 152 matched pairs with similar rates of functional independence between patients with and without CTP-mismatch profiles (17% versus 23%; P=0.42). In patients without CTP-mismatch profiles defined according to the EXTEND (Extending the Time for Thrombolysis in Emergency Neurological Deficits) criteria, recanalization was associated with improved functional outcomes. This effect was associated with baseline Alberta Stroke Program Early Computed Tomography Score and age, but not with the time from onset to imaging.

Inflammatory Type Focal Cerebral Arteriopathy of the Posterior Circulation in Children: A Comparative Cohort Study.

Inflammatory type focal cerebral arteriopathy (FCA-i) in the anterior circulation (AC) is well characterized, and the focal cerebral arteriopathy severity score (FCASS) reflects the severity of the disease. We identified cases of FCA-i in the posterior circulation (PC) and adapted the FCASS to describe these cases. In this comparative cohort study, patients from the Swiss NeuroPaediatric Stroke Registry with ischemic stroke due to FCA-i between January 2000 and December 2018 were analyzed. A comparison between PC and AC cases regarding pediatric National Institutes of Health Stroke Scale score and pediatric stroke outcome measure and FCASS was performed. We estimated infarct size by the modified pediatric Alberta Stroke Program Early Computed Tomography Score in children with AC stroke and the adapted Bernese posterior diffusion-weighted imaging score in the PC. Thirty-five children with a median age of 6.3 (interquartile range, 2.7-8.2 [95% CI, 0.9-15.6]; 20 male; 57.1%) years with FCA-i were identified. The total incidence rate was 0.15/100 000/year (95% CI, 0.11-0.21). Six had PC-FCA-i. Time to final FCASS was longer in the PC compared with AC; the evolution of FCASS did not differ. Initial pediatric National Institutes of Health Stroke Scale score was higher in children with FCA-i in the PC with a median of 10.0 (interquartile range, 5.75-21.0) compared with 4.5 (interquartile range, 2.0-8.0) in those with AC-FCA-i. Different from the anterior cases, PC infarct volume did not correlate with higher discharge, maximum, or final FCASS scores (Pearson correlation coefficient [r], 0.25, 0.35, and 0.54). FCA-i also affects the PC. These cases should be included in future investigations into FCA-i. Although it did not correlate with clinical outcomes in our cohort, the modified FCASS may well serve as a marker for the evolution of the arteriopathy in posterior FCA-i.

Comparison of consistency in acute stroke: Automated ASPECT score software tools and manual consensus scores

PurposeThe Alberta Stroke Program Early Computed Tomography Score (ASPECTS) is a standardized semi-quantitative scoring system. It is widely used to assess the extent of acute ischemic stroke (AIS). We evaluated the consistency of three automatic software packages with the overall and region-specific manual ASPECTS scores of AIS patients. MethodsRetrospectively, we gathered patients who presented with stroke symptoms between February 2019 and June 2022, and 174 cases were eventually included in the trial. Two radiologists reviewed the NCCT images independently; After four weeks, the same two radiologists began randomly reviewing the DWI images, discussed different scores and give consistent results as ground truth. ResultsMedian ASPECTS of the expert consensus reading was 7 (5–9). Good to excellent correlation of ASPECTS total scores among the three software tools (0.70, 0.74 and 0.83). Correlation among ground truth and Rapid-ASPECTS, RealNow-ASPECTS, ShuKun-ASPECTS (ICC = 0.51, Cronbach's α = 0.53), (ICC = 0.60, Cronbach's α = 0.70) and (ICC = 0.52, Cronbach's α = 0.64) respectively. The AUCs for Rapid, RealNow and ShuKun were 0.61, 0.67, and 0.62 respectively. The region-specific results showed a poor to good correlation. The correlations between the non-dominant and dominant cerebral hemispheres and the ground truth were statistically different (P < 0.05). ConclusionsOverall, the scoring consistency between the three automated scoring software and the ground truth is comparable, with RealNow-ASPECTS being no less consistent and effective than Rapid-ASPECTS and ShuKun-ASPECTS, and even better than both. But the consistency grade that still is developable.

CTP-Defined Large Core Is a Better Predictor of Poor Outcome for Endovascular Treatment Than ASPECTS-Defined Large Core.

Recent trials confirmed the effectiveness of endovascular therapy in patients with large ischemic cores. Yet the optimal neuroimaging modalities to define large core remains unclear. We tried to address this question by comparing the functional outcomes in patients receiving thrombectomy selected by either noncontrast computed tomography Alberta Stroke Program Early Computed Tomography Score (ASPECTS) or computed tomography perfusion (CTP). This study retrospectively selected patients enrolled in the International Stroke Perfusion Registry between August 2011 and April 2022. Patients with acute stroke with large vessel occlusion in anterior circulation treated with endovascular therapy were included. All received both CTP and noncontrast computed tomography. The primary outcome was defined as poor functional outcome represented by a modified Rankin Scale score of 5 to 6 at 3 months. Large cores were defined in terms of either (1) noncontrast computed tomography ASPECTS ≤5 or (2) core volume ≥70 mL on CTP. A total of 1115 patients were included in the analysis, of which 90 patients had ASPECTS ≤5 (8.1%) and 97 patients CTP core ≥70 mL (8.7%). A fair agreement between ASPECTS and CTP with a κ value of 0.31 (0.21-0.40) was found. Compared with patients with neither CTP nor ASPECTS large cores, those with only ASPECTS-defined large cores (ie, ASPECTS ≤5; n=56) did not have a higher adjusted odds of poor outcome (29%; odds ratio, 1.84 [0.91-3.73]; P=0.089). However, patients with CTP large core but not ASPECTS-defined large core (n=63) had a higher adjusted odds of poor outcome (60%; odds ratio, 3.91 [2.01-7.60]; P<0.001). In time-stratified subgroup analysis (>6 versus ≤6 hours), ASPECTS showed no discriminative difference between ≤5 and >5 in poor outcome for patients receiving endovascular therapy within 6 hours. CTP core ≥70 mL-defined large cores are more predictive of poor outcome than ASPECTS ≤5-defined core in endovascular therapy patients, particularly within 6 hours after stroke onset.

Rationale and design of Treatment of Acute Ischaemic Stroke with Edaravone Dexborneol II (TASTE-2): a multicentre randomised controlled trial

BackgroundEdaravone dexborneol is believed to be a novel cytoprotective drug, demonstrating a synergistic combination of antioxidative and anti-inflammatory properties in animal models. The Treatment of Acute Ischaemic Stroke with Edaravone...

Door to Puncture in Large Vessel Occlusions Pre‐ and Postimplementation of an Automated Image Interpretation and Communication Platform: A Single Center Study

Background Artificial intelligence platforms, like Viz.ai with large vessel occlusion detection, have been used for disease detection and interprovider communication. Whether this software expedites patient transfer and evaluation for treatment needs further exploration. Methods A single‐center retrospective registry was queried for patients with acute large vessel occlusion of the intracranial internal carotid, middle cerebral M1 or M2 segments, or basilar artery treated in a comprehensive stroke network (8 spokes, 1 hub) for 6 months pre‐ and post‐implementation of the Viz large vessel occlusion platform (excluding a 1‐month “washout” period). Robust regression was used to summarize time from initial hospital contact to arterial puncture (primary outcome) between periods, with prespecified subgroup analyses, which were assessed using interaction terms. Results Of the 132 patients (n = 58 preintervention), there were nonsignificantly fewer patients undergoing endovascular therapy in the postintervention period (86.2% preintervention versus 73.0% postintervention; P = 0.07). Among patients who underwent endovascular therapy (n = 50 preintervention, n = 54 postintervention), there was a nonsignificant reduction in time from first contact to arterial puncture (median 155 minute preintervention versus 116 minute postintervention; P = 0.10); however, this became significant in adjusted robust regression accounting for stroke severity, age, Alberta Stroke Program Early Computed Tomography Scale score, daytime versus nighttime and weekend versus weekday arrival, and use of perfusion imaging (β −20.9 [95% CI, −40.5 to −1.4)]. There was also a significant interaction observed for the association between spoke versus hub arrival and the Viz large vessel occlusion period, with shorter intervals observed for transferred patients (n = 32 preintervention with a median of 169 versus 142 minutes for n = 33 postintervention; P interaction &lt;0.01). Conclusion Implementation of the artificial intelligence platform was not associated with shorter intervals between initial hospital contact and neurointervention among all‐comers. A meaningful difference in time to treatment was observed among transferred patients. Larger data sets are needed to validate these observations.

Orbital infarction syndrome following mechanical thrombectomy in internal carotid artery occlusion: a case report

BackgroundOrbital ischemic syndrome is a rare entity. The clinical signs typically demonstrate acute loss of visual acuity, chemosis, proptosis, ptosis, and total ophthalmoparesis. We report a case of a man who suffered an acute internal carotid artery occlusion and developed orbital ischemic syndrome after a mechanical thrombectomy.Case presentationA 57-year-old Vietnamese (Kinh ethnicity) man was brought to the emergency room with complaints of a speech disturbance, facial palsy, and severe weakness of the left arm and leg, which had started 4 hours earlier, after waking up. The National Institutes of Health Stroke Scale 12 (NIHSS 12) revealed the neurological score at admission. A head computed tomography scan showed no intracranial bleeding and an Alberta Stroke Program Early Computed Tomography Score (ASPECTS) of 8 on the right brain. Computed tomography angiography showed an occlusion of the right internal carotid artery. After that, a mechanical thrombectomy was performed, and the internal carotid artery was completely reperfused. After 10 hours, he experienced orbital pain, proptosis, ptosis, chemosis, and ophthalmoplegia of the right orbit. He also had acute loss of visual acuity, and fundoscopic examination revealed papilledema, no retinal hemorrhage, and no bruit in orbital auscultation. Intraocular pressure in the right eye was measured at 50.5 mmHg. Computed tomography angiography showed no carotid–cavernous fistula, but slight enlargement of the right medial and lateral rectus muscles. He was treated with steroids and hyperosmolar agents and recovered 7 days later, but had persistent loss of visual acuity in the right eye.ConclusionOrbital ischemic syndrome is a rare complication after mechanical thrombectomy treatment in acute ischemic stroke that can lead to loss of visual acuity.

Sex differences in clot, vessel and tissue characteristics in patients with a large vessel occlusion treated with endovascular thrombectomy.

To improve our understanding of the relatively poor outcome after endovascular treatment (EVT) in women we assessed possible sex differences in baseline neuroimaging characteristics of acute ischemic stroke patients with large anterior vessel occlusion (LVO). We included all consecutive patients from the MR CLEAN Registry who underwent EVT between 2014 and 2017. On baseline non-contrast CT and CT angiography, we assessed clot location and clot burden score (CBS), vessel characteristics (presence of atherosclerosis, tortuosity, size, and collateral status), and tissue characteristics with the Alberta Stroke Program Early Computed Tomography Score (ASPECTS). Radiological outcome was assessed with the extended thrombolysis in cerebral infarction score (eTICI) and functional outcome with the modified Rankin Scale score (mRS) at 90 days. Sex-differences were assessed with multivariable regression analyses with adjustments for possible confounders. 3180 patients were included (median age 72 years, 48% women). Clots in women were less often located in the intracranial internal carotid artery (ICA) (25%vs 28%, odds ratio (OR) 0.85;95% confidence interval: 0.73-1.00). CBS was similar between sexes (median 6, IQR 4-8). Intracranial (aOR 0.73;95% CI:0.62-0.87) and extracranial (aOR 0.64;95% CI:0.43-0.95) atherosclerosis was less prevalent in women. Vessel tortuosity was more frequent in women in the cervical ICA (aOR 1.89;95% CI:1.39-2.57) and women more often had severe elongation of the aortic arch (aOR 1.38;95% CI:1.00-1.91). ICA radius was smaller in women (2.3vs 2.5 mm, mean difference 0.22;95% CI:0.09-0.35) while M1 radius was essentially equal (1.6vs 1.7 mm, mean difference 0.09;95% CI:-0.02-0.21). Women had better collateral status (⩾50% filling in 62%vs 53% in men, aOR 1.48;95% CI:1.29-1.70). Finally, ASPECT scores were equal between women and men (median 9 in both sexes, IQR 8-10vs 9-10). Reperfusion rates were similar between women and men (acOR 0.94;95% CI:0.83-1.07). However, women less often reached functional independence than men (34%vs 46%, aOR 0.68;95% CI:0.53-0.86). On baseline imaging of this Dutch Registry, men and women with LVO mainly differ in vessel characteristics such as atherosclerotic burden, extracranial vessel tortuosity, and collateral status. These sex differences do not result in different reperfusion rates and are, therefore, not likely to explain the worse functional outcome in women after EVT.

Cerebral circulation time on DSA after thrombectomy associated with hemorrhagic transformation in acute ischemic stroke.

To investigate the association between cerebral circulation time (CCT) on digital subtraction angiography immediately after thrombectomy and hemorrhagic transformation (HT) in acute ischemic stroke (AIS). Retrospectively enrolled consecutive AIS patients presented with large vessel occlusion who received thrombectomy and achieved successful recanalization between January 2019 and June 2021. The time interval from the beginning of the siphon segment of internal carotid artery visualization until the end of the arterial phase during cerebral angiography was calculated as CCT. The independent association of CCT with HT was evaluated using logistic regression analyses. The receiver operating characteristic curve was analyzed to evaluate the association between CCT and HT. Two hundred and twenty-four patients were included, of whom 86 (38.4%) suffered HT. Compared with patients without HT, patients with HT were of advanced age, less commonly male, had more diabetes mellitus, had higher baseline National Institutes of Health Stroke Scale score, lower Alberta Stroke Program Early Computed Tomographic Score, and shorter CCT (P < 0.05). Multivariable logistic regression suggested that CCT was independently associated with HT (adjusted odds ratio, 0.170; 95% confidence interval, 0.004-0.450; P < 0.001). According to the receiver operating characteristic curve, the optimal cut-off value for the strong correlation between CCT and HT was 1.72s, which had 76.6% sensitivity, 81.6% specificity, and the area under the curve was 0.846. Shorter post-thrombectomy CCT was independently associated with HT.

Abstract 84: Efficacy of Endovascular Therapy in Acute Ischemic Stroke by Alberta Stroke Program Early Computed Tomography Score and National Institutes of Health Stroke Scale-A Secondary Analysis of a Randomized Controlled Trial

Introduction and Aims: The ANGEL-ASPECT trial demonstrated the effectiveness of endovascular therapy (EVT) in acute ischemic stroke (AIS) patients with large infarct. We did a secondary analysis to explore the efficacy of EVT according to Alberta Stroke Program Early Computed Tomography Score (ASPECT) and National Institutes of Health Stroke Scale (NIHSS). Methods: ANGEL-ASPECT trial was a randomized clinical trial involving patients with acute anterior-circulation large-vessel occlusion and an ASPECT score of 3-5 or an infarct-core volume of 70-100ml. Patients were randomly assigned to EVT or standard medical treatment (SMT) alone. We categorized patients based on the combination of ASPECT (≤3 or 4-5) and NIHSS (&lt;20 or ≥20) into four groups: low ASPECT &amp; low NIHSS; low ASPECT &amp; high NIHSS; high ASPECT &amp; low NIHSS and high ASPECT &amp; high NIHSS. We assessed the efficacy of EVT using ordinal shift analysis of 90-day modified Rankin Scale (mRS). Results: Among 455 patients, the prevalence of the four groups were 190 (41.8%), 70 (15.4%), 157 (34.5%) and 38 (8.4%), respectively. A significant shift in the distribution of 90-days mRS toward better outcomes in favor of EVT was observed in patients with low ASPECT &amp; low NIHSS (common OR [cOR], 2.25; 95% CI, 1.34-3.76; P=0.002), and high ASPECT &amp; low NIHSS (cOR, 2.30; 95% CI, 1.31-4.05; P=0.004), but not in other two groups with high NIHSS (all P &gt;0.05). Conclusions: EVT was associated with better outcomes in AIS patients with large infarct and mild-to-moderate stroke severity (NIHSS &lt;20), but not in those with severe stroke severity (NIHSS ≥20). Stroke severity should be considered when planning EVT for AIS patients with large infarcts.

Abstract WP134: Door to Angiography in Large Vessel Occlusions Pre and Post Implementation of Automated Image Interpretation and Sharing Platform: A Single Center Study

Background: Viz LVO is an FDA approved software that uses artificial intelligence to identify large vessel occlusions (LVOs) on computed tomography angiography (CTA) and facilitate communication between providers in a hub-and-spoke network. Whether this software expedites patient evaluation for treatment is unexplored. Methods: A single center retrospective registry was queried for patients with LVO of the internal carotid, proximal middle cerebral, or basilar artery in a stroke network (8 spokes, 1 hub). Eligible patients were in a 6-month period before (pre-Viz) and following implementation (post-Viz) of Viz LVO. Descriptive statistics and robust regression modeling were used to describe time from first contact to angiography (primary outcome) and other intervals between pre-Viz and post-Viz study groups. Results: Of 132 included patients (n=58 pre-Viz), small differences were found in demographics and non-significantly fewer patients underwent endovascular therapy (EVT) in the post-Viz period (73.0% vs. 86.2%, p=0.07). Time from spoke arrival to hub arrival among transferred patients was non-significantly shorter post-Viz (median 124 vs. 147 min, p=0.15). In patients who received EVT, there was a non-significant reduction in time from first contact to angiography (median 116 vs. 155 min, p=0.10) with shorter intervals for transferred patients (median 142 vs. 169 min, p=0.05) but not hub arrivals (p=0.81). For transferred patients, shorter intervals from initial contact to angiography were observed in adjusted robust regression, accounting for stroke severity, age, Alberta Stroke Program Early Computed Tomography Scale score, and use of perfusion imaging (β -32.4, 95% confidence interval -61.6 to -3.26, p=0.03). Conclusions: Implementation of the Viz LVO platform was associated with shorter intervals between initial hospital contact and neurointervention among transferred patients. Larger datasets are needed to validate these observations.

Abstract 152: Endovascular Therapy versus Medical Management for Acute Ischemic Stroke With Large Infarct: A Time-Benefit Relationship Analysis

Objective: Recent randomized trials demonstrated the benefit of endovascular thrombectomy for acute ischemic stroke with large infarct. We aimed to characterize the effect of time to treatment on the benefit of endovascular therapy compared to medical management among patients with acute large ischemic stroke. Methods: Analysis the Endovascular Therapy in Acute Anterior Circulation Large Vessel Occlusive Patients with a Large Infarct Core trial (ANGEL-ASPECT), which was a multicenter, randomized trial at 46 comprehensive stroke centers in China from August 2020 to October 2022. Onset to arterial puncture time (OPT) associated with outcomes of endovascular therapy were analyzed as a category and continuous variable. The primary outcome was favorable outcome (modified Rankin scale 0-3) at 90 days. Secondary outcomes included degree of disability (modified Rankin scale range), symptomatic intracranial hemorrhage, any intracranial hemorrhage, and mortality. Results: Among 455 eligible patients, the median age was 68 years, and median Alberta Stroke Program Early Computed Tomography Score was 3 (interquartile range 3-4). Compared with medical management alone, endovascular therapy plus medical management was associated with higher rates of favorable outcome with OPT within 6 hours (44.4% vs 29.9%, adjusted odds ratio[aOR] 2.78 [95% confidence interval [CI] 1.22-6.32]), 6-12 hours (45.7% vs 29.6%, aOR 2.39 [95% CI 1.21-4.71]), but not in OPT beyond 12 hours (51.6% vs 41.4%, aOR 2.05 [95% CI, 0.88-4.77]). The benefit in favorable outcome became nonsignificant after OPT of 13 hours and 22 minutes. In three OPT intervals, the odds of better disability outcome with endovascular therapy plus medical management than medical management alone were observed; the rates of symptomatic intracranial hemorrhage and mortality were similar, though the rates of any intracranial hemorrhage increased. Conclusion: In patients with large cerebral infarction, endovascular therapy plus medical management was efficacious in improving functional outcomes with acceptable safety in a broad time window of 0 to 24 hours, but greater benefit was observed with earlier treatment. A pooled analysis with larger sample size is needed.

Abstract TMP96: Clear Thrombectomy Score: An Index to Estimate Probability of Good Functional Outcome Following Endovascular Treatment in the Late Window for Anterior Circulation Occlusion

Background: Endovascular thrombectomy (EVT) has established efficacy across a wide range of patient age, radiological findings, and clinical features. However, EVT may be less effective in extreme scenarios (e.g., large established infarction in later treatment windows), where there are currently limited data. Methods: A heterogeneous, multinational observational cohort (CLEAR registry) of consecutive adult patients ≥18 years old who underwent EVT for acute occlusion (2014-2022) of the internal carotid or proximal middle cerebral (M1 or M2) arteries was queried (n=64 sites). A high-fidelity model for predicting good functional outcome at 90 days (return to pre-stroke modified Rankin Scale [mRS] or mRS 0-2 after EVT) was developed using a binary, multivariable logit model with adaptive double lasso adjustment, which was validated using 5-fold cross validation and 1000 bootstrap sampling for confidence intervals. Results: At the time of the analysis, we evaluated 2953 patients from the registry treated with EVT, of which 1855 (63%) had complete covariate data for inclusion. The median National Institutes of Health Stroke Scale (NIHSS) score was 15 (IQR 9-20), with 14.0% having a pre-stroke mRS &gt;2, 8.3% having a NIHSS &lt;6, and 17.8% having an Alberta Stroke Program Early Computed Tomography Scale (ASPECTS) score ≤6. A good functional outcome occurred in 813 (43.8%) patients. Independent predictors of the primary outcome, with points allocated toward the final score, included younger age, higher ASPECTS, lower NIHSS, and time from last known well to arterial puncture. The areas under the curve for derivation and validation cohorts were 0.72 (95% CI 0.70-0.75) and 0.74 (95% CI 0.71-0.80), respectively. Discussion: The CLEAR thrombectomy score provides a simple, validated means of predicting good functional outcome following late-window, anterior circulation thrombectomy using routinely acquired clinical and imaging data. External validation is warranted.

Abstract 157: Endovascular Treatment of Acute Ischemic Stroke Patients With Tandem Lesions Presenting With Low Alberta Stroke Program Early Computed Tomography Score

Background and objective: The effect of endovascular therapy (EVT) in tandem lesion (TL) patients with baseline large core infarct is unclear. We investigated the safety and efficacy of EVT in TL patients with low ASPECTS (0-5). We also compared the safety of acute carotid stenting (CAS) in TLs with low ASPECTS. Methods: This prospective multicenter study from 16 centers included patients with anterior circulation TL from 2015-2020. Inclusion criteria were age ≥18 years, EVT for intracranial occlusion, and underwent treatment for extracranial ICA lesions with &gt;70% stenosis. Patients were divided into ASPECTS 0-5 and 6-10 groups. Inverse Probability of Treatment Weighting (IPTW) was used to assess the association of outcomes. Results: Of the 691 patients, 44 had an ASPECTS 0-5 and 505 had ASPECTS 6-10. After matching, there were decreased odds of favorable shift in mRS at 90 days (30.7% vs 48%, OR: 0.52, CI:0.29-0.97; p=0.002), higher rates of sICH (11.4% vs 3.6%, OR: 3.18, CI: 1.07-9.49; p=0.038), 90-day mortality (35.9% vs 16.3%; OR: 2.35, CI: 1.16-4.74; p=0.017) and comparable rates of successful reperfusion (79.5% vs 88.7%; OR: 0.73, CI: 0.33-1.63, p=0.45), excellent reperfusion (50% vs 49.1%; OR: 1.35, CI: 0.72-2.53; p=0.35) excellent reperfusion (50% vs 49.1%; OR: 1.35, CI: 0.72-2.53; p=0.35) in the ASPECTS 0-5 compared with 6-10. Among patients with ASPECTS 0-5, no significant differences were noted for sICH (OR: 0.31, CI: 0.03-3.05; p=0.32), PH2 (OR: 1.14, CI: 0.26-5.02; p=0.86), petechial hemorrhages (OR: 0.79, CI: 0.10-6.05; p=0.82), and 90-day mortality (OR: 0.68, CI: 0.14-3.45; p=0.6) in patients with stenting (18/44) versus no-stenting (25/44). Conclusion: This multicenter cohort study of AIS patients with TLs demonstrated poor outcomes for functional independence at 90 days and higher rates of sICH and mortality in patients with low ASPECTS (0-5). Among patients with ASPECTS 0-5, rates of sICH and mortality were similar in stenting and non-stenting groups.

Abstract TP193: Impact of Number of Passes on Outcomes of Mechanical Thrombectomy in Stroke Patients With Low ASPECTS

Introduction: Real-world data showed that less than half of the acute ischemic stroke (AIS) patients with large vessel occlusion (LVO) presenting with low Alberta Stroke Program Early Computed Tomography Score (ASPECTS) (2-5) achieved favorable outcomes at 90 days after mechanical thrombectomy (MT). In this study, we aim to investigate the relationship between the number of MT passes at which successful recanalization is obtained and outcomes in LVO-related AIS patients with low ASPECTS. Methods: This retrospective cohort study was performed on the data from 31 thrombectomy-capable centers between 2013 to 2022. Successful recanalization was defined as modified Thrombolysis in Cerebral Ischemia Score≥ 2b. The primary outcome was a 90-day modified Rankin Scale (mRS) of 0-3. Secondary outcomes were symptomatic intracranial hemorrhage and intracranial hemorrhage within 24 hours and mortality at 90 days. Outcomes were compared among patients with unsuccessful recanalization, and successful recanalization at first, second, third, and more than four passes. Results: A total of 297 patients with a median age of 70 [IQR 59-78] years were included and 140 (47.1%) were female. In 239 (80.4%) patients, successful recanalization was achieved: 88 patients (29.6 %) with 1 pass, 59 patients (19.9 %) with 2 passes, 35 patients(11.8%) with 3 passes, and 57 patients (19.2%) with more than 4 passes. Compared to unsuccessful recanalization, successful recanalization at first pass (adjusted OR 5.25, 95% CI 1.78 - 17.1), second passes (adjusted OR 5.20, 95% CI 1.68 - 17.6), and passes 4 (adjusted OR 4.90, 95% CI 1.68 - 17.6) was related to 90-day mRS 0-3. Recanalization status and MT attempt number were not related to secondary outcomes except for 90-day mortality. Compared to unsuccessful recanalization, successful recanalization at second and third passes were inversely related to 90-day mortality (adjusted OR 0.37, 95% CI 0.14 - 0.93; adjusted OR 0.33, 95% CI 0.11 - 0.95, respectively). Conclusion: The present results indicated that successful recanalization was related to 90-day good outcome regardless of the number of MT passes but the odds of achieving favorable outcome declines with each pass.