bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract P473: Perfusion Imaging Identifies Patients With Mild Deficits Due to Large Vessel Occlusion Who May Benefit From Endovascular Thrombectomy: A Pooled International Cohort Study
Authors: Sarraj Amrou , Ribo Marc , Blasco Jordi , Perez de la Ossa Natalia , Chen Michael , Hassan Ameer E , Wu Teddy Y , Cordato Dennis , Kleinig Timothy J , Schaafsma Joanna D , Blackburn Spiros , Abraham Michael G , Gibson Daniel , Wallace Adam , Pujara Deep , Shaker Faris , Moreno Negrete Javier , Beharry James , Cappelen-Smith Cecilia , Rodríguez-Esparragoza Luis , Olivé Gadea Marta , Requena Manuel , Pereira Vitor , Day Arthur L , Sitton Clark , Martin-schild Sheryl B , Song Sarah , Mitchell Peter J , Parsons Mark , Grotta James C , Albers Greg
Published: March 2021

Background:
Efficacy and safety of endovascular thrombectomy (EVT) in large vessel occlusion (LVO) patients with mild deficits is unclear.

Methods:
Pooled cohort of pts with mild deficits (NIHSS<6) due to (ICA, M1, M2) LVO from EXTEND IA TNK I & II RCTs and prospective data from 12 centers (US, AUS, NZ, Canada, Spain) from 1/2013 to 2/2020 was divided into medical management (MM) vs EVT. All pts had baseline CT, CTA, CTPRAPID software estimated ischemic core and mismatch. Pts stratified into with or without target profile (≥1cc core / mismatch ratio ≥ 1.8 / mismatch volume ≥ 15cc). Primary outcome- excellent (90 day mRS 0-1); Secondary- mRS shift, safety (sICH, neuro-worsening, mortality).

Results:
Of 371 pts, 189 (51%) had EVT. Time LKW to EVT center: EVT 165 (70- 416) vs MM 200 (72-564) min, p=0.35 were similar. EVT pts had larger perfusion lesions (51 cc (23-86) vs 30.1 (5, 65), p<0.001), higher NIHSS 4 (2-5) vs 3 (2-4), p=0.009), less IV tPA (30% vs 41%, p=0.044), more M1s (44% vs 29%, p<0.001). 93 pts (25%) had target profile, of whom 60% had EVT. Of 278 without target profile, 48% had EVT. Among all pts, excellent outcomes and mRS distribution were similar (EVT 63.5% vs MM 59.1%, aOR 1.55, 95%, p=0.16) and (adj cOR 1.44, p=0.16) Fig 1A. EVT had worse safety; sICH (6% vs 0%, p=0.002); neuro-worsening (19% vs 3%, p<0.001) and mortality (5% vs 1%, p=0.06). With target profile, EVT associated with more excellent outcomes (66% vs 49%, aOR 4.44, 95% CI 1.04-18.95, p=0.04), shift to better outcomes (adj cOR 2.9, 95% CI 1.03-7.91, p=0.04) Fig 1B. Safety was similar; sICH 2% vs 0%, p>0.99, neuro-worsening 17% vs 6%, p=0.30) and mortality 5% vs 3%, p>0.99). Without target profile, excellent outcomes were similar without a shift, Fig 1C. Safety was worse with EVT: sICH 8% vs 0%, p=0.001; neuro-worsening 20% vs 3%, p<0.001).

Conclusion:
EVT was not associated with improved outcomes in patients with mild deficits; safety was worse. However, EVT was safe and associated with improved outcomes in target profile patients.
Abstract P475: Intravenous Alteplase and Successful Recanalization Predict Good Outcome in Patients With M3 Segment Occlusions Undergoing Thrombectomy
Authors: Snyder Thomas , De Havenon Adam H , Nguyen Thanh , Zaidat Osama O , Yaghi Shadi
Published: March 2021

Introduction:
Advancements in the technology and techniques of clot removal has resulted in more distal clots becoming accessible for mechanical thrombectomy. The goal of this study was to assess the predictors of good outcome in stroke patients who underwent mechanical thrombectomy (MT) of the M3 segment of the middle cerebral artery.

Methods:
We performed a post-hoc analysis data from the North American Solitaire Stent Retriever Acute Stroke (NASA) and Trevo Stent-Retriever Acute Stroke (TRACK) registries. We included patients with middle cerebral artery occlusion of the M3 segment treated with MT within 24 hours of last normal. The primary outcome was 90-day modified Rankin Scale of 0-2, which we termed good outcome. We fit logistic regression models and adjusted for variables selected with backwards stepwise selection set to p<0.05.

Results:
We included 131 patients; mean age 69.5, 43.5% male, and 13/131 (9.9%) had symptomatic intracranial hemorrhage. At 90 days, 66 patients (50.4%) had good outcome. The most predictive variable for good outcome was successful recanalization (103/131), which had an adjusted odds ratio (aOR) of 18.78 (95% confidence interval (CI) 4.07-86.7; p= <0.001). Intravenous alteplase was also associated with good outcome (aOR 3.13; 95% 1.20-8.12; p = 0.0019). Higher baseline mRS and NIHSS were associated with a decreased probability of good outcome, aOR= 0.39 (95% CI 0.22- 0.72; p = 0.002) and aOR = 0.89 (95% CI 0.82- 0.97; p = 0.006). Rescue endovascular therapy was also associated with a decreased probability of good outcome aOR 0.17; (95% CI 0.05-0.66; p = 0.010).

Conclusion:
Patients undergoing MT of the M3 segment were more likely to achieve good outcome if successfully recanalized or intravenous alteplase was administered prior to thrombectomy. Rescue treatments were associated with a lower likelihood of good outcome.
Abstract P476: Safety and Efficacy of Balloon Mounted Drug-Eluting Stent in the Treatment of Symptomatic Intracranial Atherosclerotic Disease Multicenter International Experience
Authors: Mohammaden Mahmoud , Nogueira Raul G , TEKLE WONDWOSSEN , siddiq farhan , Haussen Diogo C , Elbassiouny Ahmed , Aref Hany , Grigoryan Mikayel , Hanel Ricardo , Cortez Gustavo , Ortega Santiago , Zevallos Cynthia , Mudassir Farooqui , Maud Alberto , Sheth Sunil , Spiegel Gary R , Kan Peter Tze Man , Burkhardt Jan-Karl , Hassan Ameer E
Published: March 2021

Introduction:
Intracranial atherosclerotic disease (ICAD) is a common cause of refractory stroke. Randomized clinical trials failed to prove the safety and efficacy of the endovascular treatment options of symptomatic ICAD (sICAD). However, there are many concerns regarding inclusion criteria in these trials which made them less effective than standard medical management. Herein, we aim to study the safety and efficacy of drug-eluting balloon mounted stents (DES) in the treatment of sICAD.

Methods:
A retrospective review of endovascular database from 10 comprehensive stroke centers inside and outside the USA from January 2017 to January 2020 was reviewed. Patients were included if they had symptomatic intracranial stenosis ≥70% in the target vessel, failed best medical management, and underwent intracranial stenting with DES. The primary outcome was the occurrence of ischemic stroke, hemorrhage, or mortality within 72 hours of the procedure. Secondary outcomes included rates of symptomatic and angiographic recurrence within 6 months of the procedure.

Results:
There was a total of 129 patients, the median age was 65 [58-72] years, 40 (31%) were females. The intracranial stenotic lesions were located in anterior circulation in 74 (57.4%) of cases [24 (18.6%) supraclinoid ICA, 5 (3.9%) cavernous ICA, 17 (13.2%) petrous ICA, 5 (19.4%) MCA-M1, and 3 (2.3%) M2] and in posterior circulation in 55 (42.6%) of cases [36 (27.9) vertebral artery V4 segment, 18 (14%) basilar and 1 (0.7%) PCA]. Recurrent stroke was the qualifying event in 101 (78.3%) while transient ischemic attacks (TIA) were identified in 28 (21.7%) of cases. The median time from the qualifying event to stenting was 6 [2-24] days. Strokes were reported within 72 hours of the procedure; 2 (1.6%) ischemic, 2 (1.6%) hemorrhagic strokes and 2 (1.6%) patients suffered inpatient mortality. The median follow-up time was 6 [3-6.75] months. Among 99 patients who had clinical follow up 2 (2%) had TIA and 6 (6.1%) had strokes. Fifty-one patients had follow-up imaging of whom symptomatic ISR was reported in 8 (15.7%).

Conclusion:
Our study has shown that in appropriately selected patients with sICAD, endovascular treatment using DES is safe and effective. Prospective randomized clinical trials are warranted.
Abstract P478: One-Year Outcome After Endovascular Treatment for Acute Basilar Artery Occlusion
Authors: Li Fengli , Sang Hongfei , Song Jiaxing , Guo Zhangbao , Liu Shuai , Luo Weidong , Yuan Junjie , Qiu Zhongming , Li Linyu , Zi Wenjie , Yang Qingwu
Published: March 2021

Background and Objective:
To report the results of clinical follow-up at 1 year among patients in the BASILAR registry.

Design, Setting, and Participants:
The BASILAR study was an investigator-initiated prospective registry, which consecutively enrolled stroke patients with acute basilar artery occlusion from 47 comprehensive stroke centers in China between January, 2014, and May, 2019. Patients were divided into conventional treatment or endovascular treatment groups according to the treatment their received. We assessed clinical outcomes 1 year after patients were enrolled in the BASILAR registry.

Main Outcomes and Measures:
The primary outcome was the score on the modified Rankin scale (range, 0 to 6 points, with higher scores indicating more severe disability) at 1 year assessed as a common odds ratio using ordinal logistic regression shift analysis, adjusted for prespecified prognostic factors. Secondary outcomes included categories scores of the modified Rankin scale at 1 year (0 to 1 [excellent outcome], 0 to 2 [good outcome], and 0 to 3 [favorable outcome]), and death from any cause during the 1-year period after enrollment.

Results:
Of the 829 patients who were enrolled in the original study, 1-year data for this extended follow-up study were available for 785 patients (94.7%). The distribution of outcomes on the modified Rankin scale favored endovascular treatment over conventional treatment (adjusted common odds ratio, 4.50; 95% confidence interval [CI], 2.81 to 7.29; P < 0.001). There were significant differences between the treatment groups in the percentage of patients who had excellent outcome, good outcome and favorable outcome. The cumulative 1-year mortality rate was 54.6% in the endovascular treatment group and 83.5% in the conventional treatment group (adjusted hazard ratio, 4.36; 95% CI, 2.69 to 7.29; P < 0.001).

Conclusions and Relevance:
In this extended follow-up study, the beneficial effect of endovascular treatment on functional outcome at 1 year in patients with acute basilar artery occlusion was similar to that reported at 90 days in the original study.
Abstract P481: Time to Reperfusion Determines Clinical Outcomes Independent of Post Thrombectomy Infarct Volume
Authors: Desai Shashvat , Aghaebrahim Amin N , Siegler James E , Monteiro Andre , Jadhav Ashutosh P , Jovin Tudor G
Published: March 2021

Introduction:
Late time window thrombectomy trials demonstrated that good functional outcomes can be achieved up to 24 hours from stroke onset in Slow Progressors (small infarct volume and large penumbral volume). In this study, we aim to investigate whether early (<6 hours) recanalization leads to superior functional outcomes compared to delayed recanalization (>6 hours) amongst patients with similar 24-hour infarct volumes post thrombectomy.

Methods:
We performed a retrospective analysis of a prospectively maintained LVO stroke thrombectomy database across 3 comprehensive stroke centers. Demographic, clinical, radiological, and outcomes data were analyzed. Inclusion criteria were witnessed onset anterior circulation LVO [internal carotid or middle cerebral artery M1] strokes with a good baseline mRS score (0-1) having achieved success recanalization [mTICI 2b-3] and 24-hour infarct volume of ≤10 ml on CT head or MRI. Univariate and multivariate analysis of the impact of time to recanalization on clinical outcomes was performed.

Results:
Of the 499 LVO strokes undergoing thrombectomy, 30% (148) met inclusion criteria. Mean age was 70 ±14 and median NIHSS score was 17 (14-21). Early recanalization (<6h) was achieved in 65% (96) of patients. Baseline demographic (age: 73 vs 74, p=0.80) and clinical characteristics (NIHSS:16.5 vs 17, p=0.52; 24-h infarct volume: 4.4 vs 4.2 ml, p=0.60) were comparable between early versus late recanalization patients. Rates of early clinical improvement (24-h NIHSS <6) (71% vs 39%, p=0.0007) and mRS 0-2 at 90 days (68% vs 48%, p=0.019) were higher in early recanalizers compared to late recanalizers. Multivariate analysis including age, NIHSS, time to recanalization, and 24-hour infarct volume identified early recanalization as an independent predictor of mRS 0-2 at 90 days (OR-2.41 95% CI 1.89-4.50). Every 1-hour increase in time to recanalization decreased the odds of 90-day mRS 0-2 by 2.2%.

Conclusion:
Among patients with similar 24-hour infarct volume post thrombectomy (≤10 ml), shorter time to successful recanalization is associated with significantly higher rates of early clinical improvement and mRS 0-2 at 90 days. Increased penumbral ischemic time may have an impact on outcomes post stroke thrombectomy.
Abstract P482: Outcome of Endovascular Thrombectomy for Ultra-Long Aeromedical Transfers: The Experience of 1 Hub and 11 Spoke Sites Covering More Than 1.8 Million Km
2
Authors: Pakrah Sepideh , Huang Karen , Berrill Haylee , Tan Meng , Bailey Peter , Sabet Arman , Chia Ghim Song , Devilliers Laetitia , Rice Hal , Shah Darshan
Published: March 2021

Background:
Local endovascular services for acute stroke in rural and remote regions remain a significant challenge despite higher rates of stroke in these regions.

Aim:
We present time metrics, logistical, safety and outcome data on large vessel occlusion (LVO) patients receiving endovascular thrombectomy (EVT) that were aeromedically transferred from rural and remote “spoke” sites to the Gold Coast University Hospital (GCUH) “hub”.

Methods:
This is a retrospective observational study utilizing prospectively collected stroke database from December 2018 to March 2020. Aeromedical transfers from ten rural and remote Queensland sites and one northern New South Wales site were included, covering more than 1.853 million km
2
catchment.

Results:
20 out of 26 transferred patients underwent EVT over this period. Mean distance was 1380.5 km, median time of ictus to re-canalization was 928 minutes and TICI 2b-3 was achieved in 90% of the patients. One out of 20 patients (5%) had symptomatic ICH (sICH), and 9 out of 20 (45%) achieved functional independence (mRS 0-2) at 90 days; similar to the recent pivotal trials.

Conclusions:
Our 12-center network experience confirms real world reproducibility of trial results including ultra-long transfers and supports such transfers at other centers worldwide.
Abstract P483: Immediate Feedback to Emergency Medical Services Reduce Door to Angiogram and Transfer Time for Endovascular Treatment of Large Vessel Occlusion Ischemic Strokes
Authors: Yescas Garibay Kimberley Stephania , Vo Nguyen , Jung Syung , Lee Sun
Published: March 2021

Background:
The morbidity of acute ischemic Stroke (AIS) caused by a large vessel occlusion (LVO) can be significantly reduced with endovascular intervention. However, delay in diagnosis can exclude a patient from therapy.Rapid Arterial Occlusion evaluation (RACE) score of five or more have an 85% chance of being LVO acute ischemic stroke. Pre-arrival notification of potential LVO cases by EMS (Emergency Medical Service) is an important factor to reduce door-to-transfer time from a Primary Stroke Center (PSC) to a Comprehensive Stroke center (CSC). We hypothesize that immediate feedback to EMS teams on their pre-hospital RACE score reporting will improve prehospital recognition of LVO strokes. Therefore, reducing the Door to Needle CTA (CT Angiogram) and/or Door to Transfer Time for endovascular treatment.

Methods:
Our inclusion criteria included patients with a diagnosis of AIS brought in by EMS with a RACE score of five or more, was given IV thrombolytics, or transferred to a comprehensive stroke center for endovascular treatment. A 5-item feedback form was developed for each case and was reviewed biweekly with our EMS liaison. Feedback included compliance with RACE score reporting, presence of IV access, CTA time, and TPA/Transfer time. Direct feedback was verbally given to the EMS transport team.

Results:
Comparison of data from a twelve-month preintervention period (n=29) to a four-month postintervention period (n=12) was conducted through direct comparison. This showed a decrease in mean Door-to-CTA time from 212.14 (CI ±83.3) to 97.08 (CI ±54.92) minutes with a p-value of 0.0126 in a one-tailed t-Test, a 54% reduction and a reduction in door to transfer time (305 minutes to 132 minutes,
a 56.7 % reduction
).

Conclusion:
A pilot project focused on providing immediate feedback to EMS regarding accurate prehospital notification of RACE score showed a statistically significant improvement in door to CTA time and door to transfer time. Extension of the post study period is needed to confirm the significance of transfer time. This study demonstrates the importance of collaboration between a PSC and EMS to ensure prompt diagnosis and transfer for endovascular treatment of AIS caused by LVO.
Abstract P487: Cerebral Endothelial Cell-Derived Small Extracellular Vesicles Enhance Neurovascular Function and Neurological Recovery in Rat Ischemic Stroke
Authors: Li Chao , Wang Chunyang , Zhang Yi , Alsrouji Owais K , Chebl Alex B , Mayer Stephan A , Lu Mei , Marin Horia , Kole max , Zhang Li , Chopp Michael , Zhang Zheng Gang
Published: March 2021

Background:
Treatment of patients with cerebral large vessel occlusion with thrombectomy and tissue plasminogen activator (tPA) often leads to incomplete reperfusion. There is a compelling need to develop therapies to enhance the perfusion and to improve neurological outcomes.

Methods:
Using rat models of embolic middle cerebral artery occlusion (eMCAO) and transient MCAO (tMCAO), we investigated the effect of small extracellular vesicles (sEVs) derived from healthy rat cerebral endothelial cells (CECs) administered intravenously in combination with tPA (CECs/tPA) and as an acute intraarterial adjunct therapy with mechanical reperfusion on stroke outcomes. Recanalization, cerebral blood flow (CBF), and blood-brain barrier (BBB) permeability were analyzed. MicroRNAs (miRs) and proteins were analyzed in CECs harvested from ischemic rats by RT-PCR and Western blots. Transmission electron microscopy was employed to analyze the brain distribution of CEC-sEVs. The effect of sEVs derived from clots acquired from patients undergone thrombectomy was tested on human CEC permeability.

Results:
CEC-sEVs/tPA given 4h after eMCAO or CEC-sEVs given upon reperfusion after 2h tMCAO significantly reduced infarct volume by ~36% and ~43%, respectively, and robustly improved neurological outcomes compared with tPA or ischemia/reperfusion alone (n=10 rats/group). CEC-sEVs/tPA and upon reperfusion after eMCAO or tMCAO, resepectively, significantly increased recanalization of the occluded MCA, enhanced CBF and reduced BBB leakage. CEC-sEVs/tPA substantially reduced a network of microRNAs and proteins that mediate thrombosis, coagulation and inflammation in CECs. Moreover, CEC-sEVs intravenously administered crossed the BBB and were internalized by CECs cells, astrocytes, and neurons. Stroke patient-clot derived exosomes impaired human CEC permeability and upregulated pro-inflammatory and -coagulatant proteins, which were blocked by CEC-sEVs.

Conclusion:
CEC-sEVs have a therapeutic effect on acute ischemic stroke in rats by reducing neurovascular damage. Suppressing the network of pro-thrombotic, -coagulant and -inflammatory microRNAs and proteins in CECs by CEC-sEVs likely contributes to the therapeutic effect of CEC-sEVs.
Abstract P488: The Impact of First Pass Effect on Acute Ischemic Stroke Clinical Outcomes: Why We Need to Continue to Improve Mechanical Thrombectomy?
Authors: Hassan Ameer E , Dibas Mahmoud , Ehab El-Qushayri Amr , Ghozy Sherief , Dmytriw Adam A , G Tekle Wondwossen , Sarraj Amrou
Published: March 2021

Background:
Mechanical thrombectomy (MT) has significantly improved outcomes of acute ischemic stroke (AIS) patients due to large vessel occlusion (LVO). The first-pass effect (FPE), defined as achieving complete reperfusion (mTICI3/2c) with a single pass, was reported to be associated with higher functional independence rates following EVT and has been emphasized as an important procedural target. We compared MT outcomes in patients who achieved FPE to those who did not in a real world large database.

Method:
A retrospective analysis of LVO pts who underwent MT from a single center prospectively collected database. Patients were stratified into those who achieved FPE and non-FPE. The primary outcome (discharge and 90 day mRS 0-2) and safety (sICH, mortality and neuro-worsening) were compared between the two groups.

Results:
Of 580 pts, 261 (45%) achieved FPE and 319 (55%) were non-FPE. Mean age was (70 vs 71, p=0.051) and mean initial NIHSS (16 vs 17, p=0.23) and IV tPA rates (37% bs 36%, p=0.9) were similar between the two groups. Other baseline characteristics were similar. Non-FPE pts required more stenting (15% vs 25%, p=0.003), and angioplasty (19% vs 29%, p=0.01). The FPE group had significantly more instances of discharge (33% vs 17%, p<0.001), and 90-day mRS score 0-2 (29% vs 20%, p<0.001), respectively. Additionally, the FPE group had a significant lower mean discharge NIHSS score (12 vs 17, p<0.001). FPE group had better safety outcomes with lower mortality (14.2% vs 21.6%, p=0.03), sICH (5.7% vs 13.5, p=0.004), and neurological worsening (71.3% vs 78.4%, p=0.02), compared to the non-FPE group.

Conclusion:
Patients with first pass complete or near complete reperfusion with MT had higher functional independence rates, reduced mortality, symptomatic hemorrhage and neurological worsening. Improvement in MT devices and techniques is vital to increase first pass effect and improve clinical outcomes.
Abstract P49: Pattern of Cerebral Microbleeds and Cerebral Amyloid: The ARIC-PET Study
Authors: Gottesman Rebecca F , Knopman David , Mosley Thomas , Wong Dean F , Johansen Michelle C , Walker Keenan , Jack Clifford R , Pike James R , Graff-radford Jonathan
Published: March 2021

Background:
Cerebral microbleeds (CMBs) are associated with cognitive decline, but their importance outside of clinical cerebral amyloid angiopathy is less well understood, as are the mechanisms of their impact on cognition. In a community-based dementia-free cohort, we evaluate cross-sectional associations between CMB patterns and cerebral amyloid β (Aβ) deposition, measured by florbetapir PET.

Methods:
ARIC-PET recruited nondemented individuals from 3 US sites. Participants completed 3T brain MRI with T2*GRE (with CMBs read for presence, frequency, location (lobar vs subcortical), and pattern, as well as florbetapir (Aβ) PET (global cortical standardized uptake value ratio >1.2 as a positive scan). Multivariable (see Table) logistic regression models of Aβ+ scans evaluated CMB presence, frequency, location, and pattern, in separate models. Effect modification by sex, race, APOE status, and cognition (normal vs mild cognitive impairment) was evaluated.

Results:
Nearly 25% of the 322 individuals included had CMBs. No significant associations were found between CMBs (presence or number) and Aβ positivity, but a pattern of isolated lobar CMBs or superficial siderosis was associated with over a 4-fold higher odds of elevated Aβ vs having no CMBs, without a similar elevated risk in those with isolated subcortical CMBs or mixed subcortical + either lobar CMBs or superficial siderosis. Although no significant interactions were found, a mixed pattern was nonsignificantly protective (OR estimates 0.4-0.6) and lobar only CMBs had a (nonsignificantly) higher risk (OR up to 6.4) of Aβ for three subgroups: women (vs men); Blacks (vs whites), APOE ε4 noncarriers (vs carriers), and cognitively normal (vs MCI).

Conclusions:
A lobar-only pattern of CMBs is most strongly associated with brain Aβ, with no elevated risk for a mixed CMB pattern. Further study is needed to understand differences in these CMB patterns and their meaning across distinct demographic subgroups.
Abstract P490: Influence of Balloon Guide Catheter Use on Procedural & Clinical Outcomes in the Escape-NA1 Trial
Authors: Ospel Johanna , Marko Martha , Singh Nishita , Cimflova Petra , Mayank Arnuv , Nogueira Raul G , McTaggart Ryan A , Demchuk Andrew M , Poppe Alexandre Y , Almekhlafi Mohammed , MENON Bijoy K , Hill Michael D , Goyal Mayank
Published: March 2021

Purpose:
We assessed whether balloon guide catheter (BGC) use during endovascular thrombectomy (EVT) influences procedural and clinical outcomes in the ESCAPE-NA1 trial.

Methods:
ESCAPE-NA1 was an international multicenter trial that randomized large vessel occlusion stroke patients who underwent endovascular thrombectomy (EVT) to receive Nerinetide vs. placebo. Information on EVT techniques and devices was extracted from angiographic images and procedure report forms. Effect estimates of BGC use on angiographic and clinical outcomes were obtained with logistic regression with adjustment for age, ASPECTS, baseline NIHSS, occlusion site, alteplase and study drug treatment.

Results:
Detailed information on EVT devices and technique was available for 891/1105 (80.6%) patients. A BGC was used in 599/891 patients (67.2%). BGC use was most common with a retrievable stent use (with or without distal access catheter) as the first-line approach (in 252/266 cases [94.7%] vs. combined approach (both aspiration and SR): 288/414 [69.6%], vs. contact aspiration: 37/159 cases [23.3%]). Overall, eTICI 2b/3 rates with vs. without BGC did not differ significantly (525/598 [87.8%] vs. 260/292 [89.0%]), but eTICI 2c/3 rates were significantly higher when a BGC was used (304/598 [50.8%] vs. 126/292 [43.2%], adjusted OR 1.39 [95%CI 1.05 - 1.9]). Good outcomes (mRS 0-2) were not associated with BGC use (adjusted OR 1.07 [95%CI 0.78 - 1.48]).

Conclusion:
BGC use was associated with a greater proportion of near-complete reperfusion, while there was no significant association with clinical outcomes.
Abstract P491: Direct or Bridging Endovascular Treatment for Stroke Due to Anterior or Posterior
Authors: Nie Ximing , Liu Liping
Published: March 2021

Objectives:
This study aims to investigate whether direct thrombectomy achieves equivalent functional outcomes compared with standard bridging therapy in patients with AIS caused by anterior and posterior circulation LVO in clinical practice.

Methods:
From a multicenter prospective registry, AIS patients with LVO who underwent EVT within 6 hours of stroke onset were enrolled in this study, and the efficacy and safety of bridging therapy and direct EVT were compared. The primary outcome was 90-day functional independence defined as the modified Rankin Scale score of 0-2. Outcomes were assessed with adjusted odds ratio (aOR) using multivariable logistic regression and propensity score matching analysis.

Results:
Of 738 patients enrolled (mean age, 66.1±11.8 years; 440 [60%] were male; 120 [16%] with posterior-circulation LVO), 474 (64%) were treated with direct EVT and 264 (36%) with bridging therapy. No significant difference was found for functional independence at 90 days between the two groups (aOR, 1.00; 95% confidence interval [CI]: 0.71-1.41; P = 0.99) (Table 1). Functional independence was more common in the posterior-circulation LVO subgroup treated with bridging therapy (OR, 0.30; 95% CI: 0.12-0.74, P-interaction < 0.01) (Figure1).

Conclusions:
Compared with standard bridging therapy, no significant difference in functional outcomes was observed for direct EVT in LVO patients treated within 6 hours. Bridging therapy may be potentially favorable for posterior-circulation LVO, which should be further researched.

Trial registry number:
ChiCTR1900022154 (www.chictr.org.cn).
Abstract P492: The Hypoperfusion Intensity Ratio is a Poor Discriminator of Infarct Growth in Fully Reperfused Patients
Authors: Ravindran Krishnan , Rodrigues Gabriel M , Haussen Diogo C , Bouslama Mehdi , Frankel Michael , Nogueira Raul G
Published: March 2021

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 CTP<6 hrs) (AUC 0.59, sensitivity 43%, specificity 68% and AUC 0.50, sensitivity 45%, specificity 55%). On multiple regression analysis, HIR was not predictive of infarct growth (regression equation=18.09+8.48x, F=2.46, p=0.11, R
2
=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.
Abstract P493: Outcomes in Young Adults With Acute Ischemic Stroke Undergoing Endovascular Thrombectomy: A Multi-Centre Experience
Authors: Chen Vanessa , Tan Benjamin , Tan Aloysius , Meyer Lukas , Fiehler Jens , Tu Tian-Ming , Tham Carol Huilian , Sia Ching-hui , Jamous Ala , Behme Daniel , Kastrup Andreas , Papanagiotou Panagiotis , Styczen Hanna , Forsting Michael , Lee Tsong-hai , Chu Chan-Lin , Fischer Sebastian , Maus Volker , Abdullayev Nuran , Kabbasch Christoph , Mönch Sebastian , Maegerlein Christian , Arnberg Fabian , Andersson Tommy , Holmin Staffan , Paliwal Prakash R , Ahmad Aftab , Gopinathan Anil , Yang Cunli , Seet Raymond C , Sharma Vijay , Chan Bernard P , Yeo Leonard
Published: March 2021

Introduction:
Endovascular thrombectomy(EVT) is considered standard of care for anterior circulation acute ischemic stroke(AIS) with large vessel occlusion(LVO). Young AIS-LVO patients have distinctly different underlying stroke mechanisms and etiologies.

Methods:
In this multicenter cohort study conducted from August 2014 to January 2020, we investigated the safety and effectiveness of EVT in young AIS-LVO patients aged≤50 years and evaluated associations between demographics, stroke etiology, neuroimaging factors and clinical outcomes, including functional outcomes, in-hospital mortality and symptomatic intracranial haemorrhage(sICH) in univariable and multivariable regression models.

Results:
275 AIS-LVO patients from 10 tertiary centers in Germany, Sweden, Singapore and Taiwan were included. The more common TOAST subtypes included cardioembolism (82/275, 29.8%) and stroke of undetermined etiology (85/275, 30.9%). Arterial dissection was the most prevalent stroke etiology (42/195, 21.5%) and had the highest rate of good functional outcomes (29/42, 69.0%). Successful reperfusion was achieved in 85.1% (234/275). Excellent and good functional outcomes were achieved in 48.0% (132/275) and 66.0% (182/275) respectively. sICH occurred in 6.5% (18/275). National Institute of Health Stroke Scale (NIHSS) at presentation was inversely related with good functional outcomes (aOR0.92, 95% CI 0.88- 0.96 per point increase, p<0.001). Successful reperfusion (aOR3.22, 95% CI 1.44-7.21, p=0.005), higher ASPECTS (aOR1.21, 95% CI 1.01-1.44, p=0.036) and bridging intravenous thrombolysis (aOR2.37, 95% CI 1.29-4.34, p=0.005) independently predicted good functional outcomes. Higher initial NIHSS (aOR1.08, 95% 1.02-1.14, p=0.007) and lower ASPECTS (aOR0.73, 95% 0.58-0.93, p=0.012) were associated with sICH. Successful reperfusion was inversely associated with in-hospital mortality (aOR0.14, 95% CI 0.03-0.57, p=0.006). Hypertension strongly predicted in-hospital mortality (aOR4.59, 95% CI 1.10-19.13, p=0.036).

Conclusion:
While differences in functional outcomes exist across varying stroke aetiologies, high rates of successful reperfusion and good outcomes are generally achieved in young AIS-LVO patients undergoing EVT.
Abstract P496: Clot Characteristics in Mechanical Thrombectomy: Interim Analysis of the EXCELLENT Registry
Authors: Nogueira Raul , Siddiqui Adnan H , De Meyer Simon F , Doyle Karen , Fiehler Jens , Hacke Werner , Hanel Ricardo , Liebeskind David S , Zaidat Osama O , Haussen Diogo C , Humphries William , Woodward Keith B , Jabbour Pascal M , Dashti Shervin R , Bozorgchami Hormozd , Levy Elad , Schirmer Clemens M , Taqi Muhammad A , De Leacy Reade A , Boor Stephan , Hussain M. Shazam , Puri Ajit S , Estrade Laurent , Andersson Tommy
Published: March 2021

Introduction:
Red blood cell (RBC) rich vs fibrin rich clots have different mechanical properties and greater knowledge about clot composition in the context of clinical, imaging, and procedural factors in mechanical thrombectomy (MT) may help with procedural optimization. The EXCELLENT Registry (NCT03685578) is a prospective, global, multi-center, observational registry of EmboTrap as the first line MT device for large vessel occlusion (LVO). We present an interim analysis of clot collected per pass in the registry.

Methods:
Five hundred thirty-three clot specimens from 376 subjects were collected by 20 sites and sent for analysis by independent Central Labs under standardized protocol. Analysis was interrupted by COVID-19, but the labs were fully operational as of June 2020 and on track to deliver results for 300 subjects in Q4. At the time of abstract submission, composition data for 234 clots from 163 subjects was available. All available data will be presented at the time of the conference.

Results:
Cardioembolic etiology (n=100) was associated with lower RBC (40.2 vs 47.2%) and higher fibrin content (31.7 vs 26.7%) compared to large artery disease (n=12). Hyperdense/vessel susceptibility sign (78+, 24-, per independent imaging core lab) corresponded to higher mean RBC content (44.4 vs 34.9%). Treatment with IV tPA (60+, 91-) had no clear impact on clot composition (42.3 vs 40.6% RBC; 30.4 vs 30.0% fibrin). Notably, clots retrieved with the first 2 passes of were more RBC rich (42.1 vs 28.0%) and clots retrieved in higher passes had a higher average fibrin content (35.5 vs 29.6%) suggesting that higher fibrin content leads to greater refractoriness.

Conclusions:
Clot density/susceptibility on baseline imaging, stroke etiology and number of thrombectomy passes were associated with differential clot composition. These findings may have potential implications for the development of better MT strategies.
Abstract P50: Obesity and Diabetes Are Associated With Increased Risk for Disability Among Community-Dwelling Stroke Survivors
Authors: Bailey Ryan
Published: March 2021

Introduction:
Stroke-related disability is common. Obesity and diabetes are associated with disability in the general population, but the elevated risk of disability in stroke survivors who also experience these conditions has not been reported. The purpose of this study was to examine prevalence of 6 disability types among stroke survivors stratified by obesity and diabetes statuses.

Methods:
Data from 37,955 non-institutionalized stroke survivors aged >18 years from the 2017 and 2018 Behavioral Risk Factor Surveillance System (BRFSS), a U.S.-based annual telephone survey, were analyzed. Self-reported disability types included deaf or difficulty hearing (deaf); blind or difficulty seeing (blind); difficulty concentrating, remembering, or making decisions (cognition); difficulty walking or climbing stairs (mobility), difficulty dressing or bathing (dressing); and difficulty doing errands alone (alone). Prevalence of disability types were computed using linear regression, and odds ratios (adjusted for demographic characteristics) among survivors with obesity (vs. normal weight) and diabetes (vs. no diabetes) were computed using logistic regression.

Results:
Prevalence of obesity and diabetes were 35.7% (95% CI: 29.5%-41.8%) and 24.8% (95% CI: 21.3%-28.3%), respectively. Prevalence was highest for mobility (36.0%), cognition (33.7%) and alone (28.3%) disability types. Compared to survivors with normal weight, survivors with obesity had elevated AORs for mobility (1.68) and dressing (1.55) disability; and compared to survivors without diabetes, survivors with diabetes had elevated AORs for all disability types (range: 1.17-1.71) (see Table).

Conclusion:
Obesity and diabetes increase risk for self-reported disability above the risk associated with stroke alone. Tailored interventions for stroke survivors with these conditions may be needed for decreasing disability and improving quality of life, and should be developed and explored.
Abstract P500: Outcomes of Mechanical Thrombectomy in Patients With Low Aspects: Insights From Star
Authors: Hubbard Zachary , Porto Guilherme B , Al Kasab Sami , Almallouhi Eyad , Spiotta Alejandro M , De Leacy Reade A , Raper Daniel , rai ansaar , Dumont Travis , Wolfe Stacey , Jabbour Pascal M , Ogilvy Christopher S , Park Min S , Levitt Michael , Polifka Adam , Crowley Richard , Arthur Adam S , Osbun Joshua , Crosa Roberto , Maier Ilko , Kim Joon-Tae , Casagrande Walter , Grossberg Jonathan A , Chowdhry Shakeel A , Mokin Maxim , Matouk Charles , Fragata Isabel , Williamson Richard , Yoo Albert J , Mascitelli Justin , Kan Peter , Psychogios Marios-Nikos , Starke Robert
Published: March 2021

Introduction:
Patients with poor baseline images were excluded from most clinical trials so the data about whether these patients could benefit from MT remains unknown. In this study, we aim to investigate the safety and efficacy of MT in patients with large vessel occlusion (LVO) and large core infarct (LCI).

Methods:
The Stroke Thrombectomy and Aneurysm Registry (STAR) was interrogated. We included thrombectomy patients presenting with LVO within 24 hours and with a LCI as defined by Alberta Stroke Program Early CT Score (ASPECTS) < 6. Patients presenting within 6 hours of last known normal (LKN) were considered in the early window and patients presenting after 6 hours were considered in the late window. 90-day outcomes were assessed. We used a logistic regression model to assess the factors associated with good 90-day outcome in patients in the early and late windows.

Results:
144 patients were included in this study (table). Median age was 69 and 92 (64%) patients were treated in the early MT window. ICA was the most common site of occlusion (48.6%) and ADAPT was used in 34.7%. Admission NIHSS was 17.5. Successful recanalization (TICI>2b) was achieved in 84.7% and median procedure time was 54 minutes. sICH hemorrhage was observed in 22 (15.3%). Median mRS was 4 at 90 days. Favorable outcome was observed in 41 patients (28.5%) and mortality occurred in in 59 (41%). There was no difference in 90-day functional outcome between patients in early and late windows. In patients presenting in the early window, age (aOR=0.905, p=0.0002) and baseline NIHSS (aOR=0.909, p=0.0423) were independently associated with 90-day outcome. In patients presenting in the late window, only age (aOR=0.934, p=0.0069) was independently associated with good outcome.

Conclusion:
More than one in four patients presenting with ASPECTS<6 may achieve functional independence at 90-day following MT. Patient age remains the main predictor of 90-day outcome in patients with low ASPECTS in both late and early windows.
Abstract P502: Significance of Asymptomatic Hemorrhage After Mechanical Thrombectomy: A Post-Hoc Analysis of the Best Study
Authors: Feldman Michael , Roth Steven , Fusco Matthew , Yaghi Shadi , Mehta Tapan V , Arora Niraj , Siegler James E , Schrag Matthew , Mistry Akshitkumar M , Chitale Rohan , Khatri Pooja , Mistry Eva A
Published: March 2021

Introduction:
Intracerebral hemorrhage (ICH) occurs in 20-30% of the stroke patients undergoing endovascular therapy (EVT). However, there is conflicting evidence regarding the effect of asymptomatic ICH (aICH) on post-EVT outcomes.

Methods:
In this post-hoc analysis of our multi-center, prospective, “Blood Pressure after Endovascular Therapy (BEST)” study, we determined the rates of patients with aICH and symptomatic ICH (sICH; any ICH associated with ≥4 points deterioration in the baseline NIH Stroke scale). Their associations with a primary outcome of 90-day modified Rankin Scores (mRS) 0-2 vs 3-6 and early neurological recovery (ENR; NIHSS of 0-1 or ≥8-point improvement at 24 hours from baseline) was determined using univariable and multivariable logistic regression models (adjusted for age, NIH stroke scale, ASPECT score, age, thrombolytic administration, and successful recanalization defined as mTICI ≥2b).

Results:
Of 485 patients included in BEST at 12 comprehensive stroke centers across the US, 446 patients had a 90-day follow-up available. Of these, 92 (20.6%) developed aICH and 18 (4%) developed sICH. The aICH was not associated with worse 90-day outcome or lower ENR (OR 1.19 [0.74-1.88], p=0.45, aOR 1.19 [0.69-2.06], p= 0.53 for 90-day mRS 3-6; OR 0.77 [0.48-1.23], p=0.30, aOR 0.72 [0.43-1.22] for ENR).A higher proportion of patients with aICH had mTICI ≥2b compared to those without any ICH (97%vs 87%, p=0.01, Table). The aICH was not associated with 90-day outcome or ENR in patients with mTICI ≥2b (OR 1.28 [0.79-2.08], p=0.32 for 90-day mRS 3-6; OR 0.89 [0.69-1.12], p=0.14 for ENR).

Conclusion:
We found insufficient evidence that aICH associated with worse outcomes in EVT-treated patients, including those with successful recanalization. Interestingly, aICH was more frequent in patients with successful recanalization. Further validation of our findings in other large cohort studies of EVT-treated patients is warranted.
Abstract P505: Prediction of Infarct Volume at the 24 Hours After Late Window Presentation With Perfusion Imaging in Patients With Anterior Circulation Large Vessel Occlusion
Authors: Agarwal Shashank , Raz Eytan , Dehkharghani Seena , Christensen Soren , Lansberg Marteen G , Albers Gregory , Yaghi Shadi , De Havenon Adam H
Published: March 2021

Introduction:
We sought to evaluate the accuracy of perfusion-weighted imaging (PWI) in late presenting patients for estimating the infarct volume at 24 hours after presentation.

Methods:
This is a secondary analysis of DEFUSE 3, which included stroke patients with anterior circulation occlusion within 6-16 hours of last known normal. The primary outcome is the final infarct volume on a 24-hour MRI scan (volume of DWI positive tissue), adjusted for the baseline infarct volume. We censored 3 patients with 24-hour follow-up MRI infarct volumes >300 mL, which we considered non-physiologic for a hemispheric stroke. The primary predictors are the baseline volume of Tmax >6s, Tmax >10s, and hypoperfusion intensity ratio (HIR: Tmax10/Tmax6) on CT/MR perfusion at hospital admission. We stratified the cohort into 4 categories (untreated, TICI 0-2a, TICI 2b, and TICI3) and fit linear regression models to each of our predictors.

Results:
We included 147 patients, of which 69 were untreated, 17 had TICI 0-2a, 46 had TICI 2b, and 15 had TICI 3. In untreated patients, both HIR and Tmax10 volume were predictive of adjusted 24-hour follow-up infarct volume (Table). In treated patients, there were no consistent relationships between the perfusion imaging variables and adjusted final infarct volume (Table).

Conclusion:
For patients with late window anterior circulation large vessel occlusion stroke, HIR and Tmax10 volume appear to be reliable predictors of subsequent infarct volume in untreated patients. For patients treated with thrombectomy, further research is warranted to better understand the more complex relationship between baseline perfusion imaging and the 24 hour, and beyond, infarct volume.
Abstract P511: Optimal Blood Pressure Targets Following Successful Revascularization With Mechanical Thrombectomy
Authors: Vu Phong T , Rajagopalan Swarna , Frey Jessica , Hone Emily , Jelsema Casey , Rai Ansaar
Published: March 2021

Background/Objective:
Blood pressure parameters for patients undergoing mechanical thrombectomy (MT) are not clearly defined. Prior studies have shown that higher maximum and mean systolic blood pressure (SBP) is associated with adverse outcomes. Our study sought to investigate the relationship of blood pressure on clinical outcomes after successful revascularization and determine optimal thresholds for BP parameters that correlated with a poor functional outcome.

Methods:
This was a retrospective observational study of 88 consecutive patients who received successful MT at one comprehensive stroke center. Systolic, diastolic, and mean arterial pressure values were recorded for each patient over a 48-hour period, as well as patient age and National Institutes of Health Stroke Scale (NIHSS). Outcome measures included modified Rankin Score (mRS), intracranial hemorrhage (ICH), and mortality at time of discharge and 90 days. Both univariable and multivariable logistic regression analysis was performed to identify associations between the BP covariates and functional outcomes.

Results:
A higher SBP standard deviation (SD) of >14mmHg (OR=1.150) and wider SBP range >64mmHg (OR=1.037) from the mean in the first 48 hours after successful MT were associated with poor MRS at 90 days. A SBP SD>14 was also associated with mortality at 90 days. A higher age (OR=1.052) and NIHSS (OR=1.096) were also associated with a poor MRS at 90 days. A higher DBP mean (OR=1.045) was associated with a higher rate of hemorrhagic transformation (HT).

Conclusions:
A higher SBP variability within the first 48 hours after successful MT is associated with a higher likelihood of poor 90-day functional outcome and mortality, and a higher mean DBP is associated with a higher rate of HT.