bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract P465: Magnitude of Blood Pressure Change and Clinical Outcomes After Thrombectomy in Ischemic Stroke Caused by Large Artery Occlusion
Authors: Anadani Mohammad , Matusevicius Marius , Peeters André , Paiva Nunes Ana , De Havenon Adam H , Ahmed Niaz ,   SITS
Published: March 2021

Background:
Extremes of both high and low systolic blood pressure (SBP) after mechanical thrombectomy (MT) in large artery occlusion stroke are known predictors of unfavorable outcome. However, the effect of SBP change (ΔSBP) during the first 24 hour on MT outcomes remains unclear. We aimed to investigate the association between ΔSBP at different time intervals and thrombectomy outcomes.

Methods:
We analyzed thrombectomy treated patients registered in the SITS International Stroke Thrombectomy Registry from 2014-01-01 to 2019-09-03. The primary outcome was 3-month unfavorable outcome (modified Rankin Scale [mRS] score 3-6). We defined ΔSBP as mean SBP of given time intervals after MT (0-2h, 2-4h, 4-12h, 12-24h) minus admission SBP. Multivariable mixed logistic regression models were used to adjust for known confounders and center as random effect. Subgroups analyses were included to contrast specific subpopulations. Restricted cubic splines were used to model the associations.

Results:
The study population consisted of 5835 patients (mean age 70 years, 51% male, median NIHSS 16). Mean ΔSBP was -12.3, -15.7, -17.2, and -16.9 for the time intervals 0-2h, 2-4h, 4-12h, 12-24h, respectively. Higher ΔSBP was associated with unfavorable outcome at all time intervals. Restricted cubic spline models suggested that increasing ΔSBP was associated with unfavorable outcomes, with higher values showing an even higher risk of unfavorable outcomes. (Figure 1). Successful reperfusion (mTICI ≥2b) retained an association between ΔSBP and outcomes, while unsuccessful reperfusion (mTICI <2b) did not.

Conclusion:
Up to our knowledge, this is the first study to examine the relation between ΔSBP at different time intervals and the outcome of MT. BP increase after thrombectomy in large artery occlusion stroke is associated with poor functional outcome. The association between ΔSBP and poor outcome differed by reperfusion status.
Abstract P466: Comparison of Three Automated Ct Perfusion Software Packages for Thrombectomy Eligibility and Final Infarct Volume Prediction
Authors: Pisani Leonardo , Mohammaden Mahmoud , Bouslama Mehdi , Al-bayati Alhamza R , Haussen Diogo C , Frankel Michael R , Nogueira Raul G
Published: March 2021

Introduction:
We aimed to compare the perfusion parametric maps and the determination of predicted ischemic core between three automated CT perfusion software packages: RAPID (IschemaView), Viz CTP (Viz.ai) and e-Mismatch (Brainomix).

Methods:
Retrospectively review of a prospective database spanning September 2018-November 2019 with the following inclusion criteria: 1) acute large vessel occlusion strokes (LVOS) involving the intracranial internal carotid artery or proximal middle cerebral artery (M1 segment), 2) available CTP images, 3) final complete/near-complete endovascular reperfusion (eTICI2c-3) and 4) follow-up imaging with final infarct volume (FIV) assessment.

Results:
A total of 242 cases were included. There was a strong correlation for rCBF<30% between RAPID and Viz CTP (r
s
=0.844, p<.001) as well of RAPID and e-Mismatch (r
s
=0.833, p<.001). Similarly, strong correlation for Tmax>6s were observed between RAPID and Viz CTP (r
s
=0.892, p<0.001) as well for RAPID and e-Mismatch (r
s
=0.752, p<.001). The accuracy for FIV prediction was found to be moderate in all three packages (RAPID: r
s
=0.637, p<.001; Viz CTP: r
s
=0.601, p<.001; e-Mismatch: r
s
=0.605, p<.001)(Figure). Ghost core (defined as FIV overestimation >10ml within 6 hours from stroke onset) was identified in 10 (15.9%) RAPID, 15 (23.8%) Viz CTP and 3 (4.7%) e-Mismatch cases.

Conclusion:
The key CTP parameters for the RAPID, Viz CTP and e-Mismatch packages strongly correlate. CTP predictability of final infarct volume remains moderate and requires further evaluation.
Abstract P47: Immediate Clinical Improvement Occurs in Patients With Aneurysmal Subarachnoid Hemorrhage and Delayed Cerebral Ischemia Treated With Hypertension Induction or Inotropics
Authors: Rouanet Carolina , Vasconcellos Natalia , Chaddad Neto Feres Eduardo , Sampaio Silva Gisele
Published: March 2021

Introduction:
Delayed cerebral ischemia (DCI) is one of the main determinants of prognosis in aneurysmal subarachnoid hemorrhage (aSAH). Hypertension induction (HI) and inotropics are frequently used strategies to treat DCI. However, little is known about clinical improvement immediately after those therapies.

Methods:
All patients with aSAH admitted to our hospital from 2016 to 2018 were evaluated. DCI was defined as a new focal neurological deficit or decrease in level of consciousness or the appearance of new infarctions on brain imaging. Patients who developed DCI and received vasopressors or inotropics and were included in the study. They were evaluated before (t0), 45 (t1) and 90 (t2) minutes after therapy initiation using NIHSS scores and Glasgow Coma Scale (GCS).

Results:
A total of 98 aSAH were evaluated, and 21 of them developed DCI (21.4%). Six patients received both treatment strategies, leading to a total of 27 DCI treatments (norepinephrine =12, milrinone =15). Mean NIHSS score had a significant decrease in t1 and t2 when compared to t0 (17 [95%CI 13-24], 16 [95%CI 11-23], 15 [95%CI 9-22], p<0.001 and p<0.002). The same happened among those treated with IH (t0=18 [95%CI 13-25]; t1=16 [95%CI 11-23], p=0.002; t2=14 [95%CI 9-22], p=0.027) and with milrinone (t0=17 [95%CI 12-24]; t1=15 [95%CI 10-23], p=0.007; t2=14 [95%CI 9-23], p=0.001). Mean GCS had a significant improvement in t1, that was not sustained in t2 (9 [95%CI 8-11], 10 [95%CI 9-12], 10 [95%CI 9-12], p=0.008 and p=0.098). In those treated with HI GCS scores did not change significantly (t0=9 [95%CI 7-11]; t1=10 [95%CI 8-12], p=0.054; t2=10 [95%CI 8-12], p=0.177). Those treated with inotropics significantly improved across time (t0=10 [95%CI 8-12]; t1=11 [95%CI 9-13], p=0.004; t2=11 [95%CI 9-13], p=0.001).

Conclusions:
DCI treatment with HI or inotropic therapy seems effective in immediately improving neurological deficits in patients with aSAH and DCI.
Abstract P471: Ipsilateral Asymmetrical Internal Cerebral Vein on Multiphasic Computed Tomography for Acute Anterior Circulation Ischemic Stroke Thrombectomy is an Independent Predictor of Poor Functional Outcome
Authors: Myint May Zin , Tan Benjamin Yong Qiang , Leow Aloysius Sheng Ting , The Ei Zune , Yang Cunli , Gopinathan Anil , Sharma Vijay , Yeo Leonard L
Published: March 2021

Background:
National Institute of health stroke scale(NIHSS) and collateral circulation are well-established predictors for functional outcomes of endovascular thrombectomy (EVT) patients in acute ischemic stroke (AIS), nonetheless additional prognostic markers can improve the prediction of stroke outcomes. The inflow and drainage into the internal cerebral veins (ICV) can be seen consistently on multiphasic computed tomography angiography (mCTA). Thus, we hypothesize that asymmetry of ICV in the mCTA in large vessel occlusion AIS can be used as an adjunctive predictor of functional outcomes and complications.

Method:
We enrolled 185 consecutive anterior circulation AIS patients who underwent EVT that presented to our hospital between 2017 and 2019. The collateral circulation was defined by the university of Calgary mCTA collateral flow assessment in stroke. The ICV on the ipsilateral occlusion side was compared with the contralateral side according to a binary scale: 1 (less than contralateral or absent) or 2(equal or greater than contralateral). The primary outcome was modified Rankin scale at 3 months (mRS), and secondary outcomes included symptomatic intracranial hemorrhage and mortality.

Result:
Among 185 patients, 53% were men, the median age 70 years (range 29-91) and the median NIHSS score on arrival (NIHSS OA) was 19 (range 4-34). 82 patients (44.3%) had good functional outcomes at 3 months. Ipsilateral asymmetry in all three stages of mCTA were statistically significantly associated with good functional outcomes. The 1
st
delay phase of mCTA showed the strongest association. On multivariate analysis, high NIHSS OA (OR 1.09, 95% CI 1.02-1.15,
P
= 0.007), good mCTA collateral score (OR 0.30, 95% CI .16- .53,
P
< .001), ipsilateral asymmetrical ICV on the 1
st
delay phase of mCTA (OR 2.64, 95% CI 1.17-5.96,
P
= 0.01) were independent predictors of poor functional outcome. Ipsilateral asymmetry was not associated with mortality or symptomatic intracranial hemorrhage on multivariate analysis.

Conclusion:
Ipsilateral assymetrical ICV is a novel radiological marker associated with functional outcomes after thrombectomy even after correction for the collateral circulation. Further studies should be done to validate this finding in different datasets.
Abstract P474: Functional Outcomes and Regional Significance of Ischemic Lesions After Thrombectomy for Large Vessel Occlusion Stroke
Authors: Regenhardt Robert W , Bonkhoff Anna K , Bretzner Martin , Etherton Mark R , Das Alvin S , Alotaibi Naif M , Vranic Justin E , Stapleton Christopher J , Patel Aman B , Leslie-Mazwi Thabele M , Rost Natalia S
Published: March 2021

Introduction:
Endovascular thrombectomy (EVT) has revolutionized large vessel occlusion (LVO) stroke care. However, over half remain functionally disabled or die despite treatment. Understanding outcomes may influence EVT selection, novel therapies, and prognostication. We sought to identify associations between outcomes and brain regions involved in ischemic lesions.

Methods:
For consecutive LVO patients with post-EVT MRI, acute ischemic lesions were manually segmented from DWI and spatially normalized. Individual lesion volumes were automatically parcellated (atlas-defined 94 cortical regions, 14 subcortical nuclei, 20 white matter tracts) and then reduced to ten anatomically plausible lesion patterns using unsupervised dimensionality reduction techniques. Ninety-day modified Rankin Scale (mRS) was modeled via Bayesian regression, taking the ten lesion patterns as inputs and controlling for lesion size, age, sex, acute NIH Stroke Scale, alteplase, and TICI 2b-3 reperfusion.

Results:
We identified 153 LVO patients with mean age 68±15 years and 51% female. Median NIHSS was 16 (IQR 13-20), 56% received alteplase, and 84% achieved TICI2b-3. The lesion patterns predictive of 90-day mRS involved bilateral subcortical nuclei, pre- and postcentral gyri, insular and opercular cortex, as well as left-sided inferior frontal and angular gyri (
Figure 1A
). Lesions affecting white matter tracts had the highest relevance predicting 90-day mRS (
Figure 1B
).

Conclusions:
These data describe the significance for outcomes of specific brain regions involved in ischemic lesions on MRI after EVT. Future work in additional datasets is needed to confirm these granular findings.
Abstract P477: A Meta-Analysis of Carotid Stenting and Angioplasty for Treatment of Tandem Occlusion Stroke
Authors: Gordon Weston R , Gronseth Gary S , Linares Guillermo
Published: March 2021

Introduction:
Acute ischemic stroke (AIS) in the setting of tandem extracranial carotid disease and intracranial large vessel occlusion (TO) is associated with poor functional outcome. It remains unclear whether the extracranial lesion requires acute stenting or angioplasty alone. Meta-analyses to date have included predominantly retrospective non-comparative series. Our meta-analysis aimed to investigate if emergent carotid stenting plus endovascular thrombectomy (EVT) is more effective than angioplasty alone plus EVT at reducing incomplete recanalization (TICI <2b/3), symptomatic ICH (sICH) rate, or poor functional outcome (mRS>2 90 days).

Methods:
Systematic review identifying TO studies comparing those undergoing carotid angioplasties alone to stenting. Results were pooled using inverse variance random effects meta-analyses. Conclusions accounted for the magnitude of effect, precision and risk of bias in the studies using the modified GRADE process of the American Academy of Neurology.

Results:
Ten non-blinded, observational studies totaling 1006 TO patients met inclusion criteria. Baseline patient characteristics were without significant confounders. Mean initial NIHSS was 15.3 and 15.0 and symptom onset-to-recanalization time was 332 and 337 minutes in the stenting and angioplasty groups, respectively. Overall, poor functional outcome at 90 days occurred in 44.6% of patients and death occurred in 13.0% of patients. There was a significant decrease in the rate of mRS>2 (OR=0.55, CI 95% 0.40 –0.76) and death (OR=0.47, CI 95% 0.24–0.94) in patients treated with stenting vs angioplasty. TICI <2b/3 occurred in 21.5% of patients overall with no statistical difference in patients treated with stenting vs angioplasty (OR=0.67, CI 95% 0.42—1.07). sICH occurred in 5.7% of patients overall and there was no statistical difference in patients treated with stenting vs angioplasty (OR=1.19, CI 95% 0.53—2.67).

Conclusion:
Emergent stenting possibly decreases the risk of mRS>2 and mortality at 90 days. There is insufficient evidence to conclude whether stenting increases the risk of TICI <2b/3 and sICH. Confidence in the evidence is low, anchored by observational study designs and absence of blinding. A randomized controlled study is warranted.
Abstract P48: Factors Associated With Delay to Treatment of Aneurysmal Subarachnoid Hemorrhage (aSAH) - A Systematic Review
Authors: Nguyen Thuy Phuong , Rehman Sabah , Stirling Christine , Chandra Ronil V , Nichols Linda , Gall Seana L
Published: March 2021

Background:
Delay in treatment of aneurysmal subarachnoid haemorrhage (aSAH) appears to be common, contributing to the poor outcomes of patients. We currently have limited understanding of the causes of these delays. The aim of this systematic review was to identify delays in treatment of patients with aSAH, and to identify factors associated with treatment delay.

Methods:
The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline was followed. We searched four electronic databases (MEDLINE, EMBASE, Web of Science, and Google Scholar) for manuscripts published from January 1998 to 2020 using pre-designated search terms and search strategy. Main outcomes were duration of delays of any time intervals from onset of aSAH to definitive treatment and/or factors related to delays.

Results:
A total of 64 studies met study entry criteria. We identified 16 different time intervals in the pathway of aSAH patients and 17 groups of predictors to delay in treatment. Most studies measured time intervals between four major time points including time of onset, hospital admission, diagnosis, and receiving coiling or clipping. Methods to measure delay in treatment varied largely between studies, using cut-off timepoints or measured absolute time duration using mean or median. Demographic factors (age, sex, race, or socioeconomic status) were not associated with time to treatment. More severe aSAH reduced treatment delay in most studies. Pre-hospital delays (patients delay, late referral, late arrival of ambulance, being transferred between hospitals or arriving at the hospital outside of office hours) were associated with treatment delay. In-hospital factors (complication, having other procedures before definitive treatment, and type of treatment) had two-way association with treatment delay - both increasing and decreasing time to treatment.

Conclusions:
This review provides the first comprehensive understanding of types and predictors of delays in treatment of aSAH. There is significant opportunity to increase the comparability of aSAH time to treatment data, and to identify pre-hospital and in-hospital factors that currently delay treatment.
Abstract P497: Comparison of Recanalization and Early Clinical Outcomes of Large Vessel Occlusion With Endovascular Therapy Following Alteplase versus Tenecteplase
Authors: Miley Jefferson T , Waldron James S , Ashour Ramsey , Warach Steven J ,   for Dell Med Sch Ascension Texas Stroke Service
Published: March 2021

Background:
Randomized trials comparing alteplase (ALT) to tenecteplase (TNK) in large vessel occlusion have reported higher rates of recanalization with evidence of better clinical outcomes. Our 10-hospital network (2 CSCs, 2PSCs, 6 non-SCs) switched the standard stroke thrombolytic from alteplase (ALT) to tenecteplase (TNK; 0.25 mg/kg) in September 2019. We describe our results in a subgroup analysis of an on-going prospective cohort study of TNK-treated vs two years of ALT treated cases.

Methods:
All cases in whom a mechanical endovascular recanalization procedure was initiated following thrombolytic therapy. Cases will be reviewed and adjudicated independently by three neurointerventionalists for partial or complete recanalization on initial angiogram compared to pretreatment CTA or MRA. Cases that could not be assessed for technical reasons (e.g., sufficient imaging studies were not present in PACS) were excluded from the recanalization analysis. All cases were included in the clinical analysis. Preliminary recanalization results available at the time of submission are presented here.

Results:
42 TNK-treated (median age 68.5y, median NIHSS 16, median Last Known Well to Groin 198 minutes) and 77 ALT (median age 67y, median NIHSS 18, median Last Known Well to Groin 198 minutes) were included. Early clinical outcomes and preliminary results on recanalization (partial or complete) are summarized in the Table. Approximately twice the rate of recanalization was seen in the TNK vs ALT cases (not statistically significant). Rates of discharge to home, in-hospital mortality/discharge to hospice, or symptomatic ICH were not different.

Conclusion:
In this non-randomized, open-label sample, a nominally higher rate of partial or complete recanalization of LVO with TNK relative to ALT, without significant differences on early indices of clinical outcome. Adjudicated analyses of recanalization on an updated TNK sample will be presented at the conference.
Abstract P5: IV Alteplase Benefits Thrombectomy Patients With Incomplete TICI 2 Endovascular Reperfusion but Not Those With Complete TICI 3 Endovascular Reperfusion
Authors: Tarpley Jason W , Ho Joseph T , Stuchiner Tamela L , Ovando Renee , Kelly Daniel , Martin Neil , Teitelbaum George P , Baraban Elizabeth
Published: March 2021

Introduction:
There is debate regarding how IV tPA influences the efficacy of Endovascular therapy (EVT). One hypothesized potential benefit of thrombolytics is in patients with incomplete endovascular reperfusion. We compared discharge disposition in EVT patients with TICI 2 or TICI 3 reperfusion who received IV tPA with those who did not.

Methods:
Data from the Providence System Stroke Registry for acute ischemic stroke patients receiving EVT between January 2015 and May 2020 with a TICI 2 or TICI 3 reperfusion grade were used. Patients presenting later than the conventional 4.5 hour IV tPA window were excluded. Multinomial regressions were used to assess if EVT patients with a TICI 2 or TICI 3 who received IV tPA compared to those who did not receive IV tPA had greater odds of being discharged as expired or hospice or other location (acute care or long term care, skilled nursing facility, left against medical advice), compared to home or inpatient rehabilitation (IRF), adjusting for patient age, sex, race and ethnicity, last known well to arrival, NIHSS at admit, and medical history. Adjusted odds ratios (AOR) and 95% confidence intervals (95% CI) are reported.

Results:
Of 419 EVT patients with TICI 2, 50.1% (n=210) received IV tPA and 49.9% (n=209) did not. Of 771 EVT patients with TICI 3, 48.4% (n=373) received IV tPA and 51.6% (n=398) did not. EVT patients with TICI 2 who were not treated with IV tPA were 59% less likely to be discharged as expired or hospice than home or IRF than those treated with IV tPA (AOR=0.414, 95% CI: 0.203, 0.844), and 63% less likely to be discharged somewhere other than home/IRF (AOR=0.372, 95% CI: 0.217, 0.636) than home/IRF. Among EVT patients with TICI 3, multivariate analyses indicated there was no greater likelihood of being discharged expired or to hospice than home/IRF (AOR=0.682, 95%CI: 0.434, 1.07) or discharged somewhere other than home/IRF (AOR=0.839, 95%CI: 0.592, 1.19) between those who received IV tPA and those who did not.

Conclusions:
Thrombectomy patients with TICI 2 reperfusion had better discharge outcome if they were treated with IV tPA. However, in completely reperfused patients with TICI 3 reperfusion outcome was not affected by prior IV tPA administration.
Abstract P508: Transradial Cerebral Angiography Becomes More Efficient Than Transfemoral; Lessons From 500 Consecutive Angiograms
Authors: Wilkinson D. Andrew , Majmundar Neil , Catapano Joshua , Cavalcanti Daniel , Frederickson Vance , Ducruet Andrew F , Albuquerque Felipe C
Published: March 2021

Introduction:
Transradial arterial access (TRA) for cerebral diagnostic angiography (DSA) is associated with reduced access-site complications compared with transfemoral access (TFA), though concerns about increased procedure time and radiation exposure may slow its adoption.

Objective:
To examine “radial-first” cerebral angiography by measuring TRA rates of success and fluoroscopy time and comparing to TFA.

Methods:
We examined 500 consecutive cerebral angiograms during the first full year of “radial-first” adoption, recording patient and procedural characteristics including intended and performed access sites, fluoroscopy time per vessel catheterized, and outcomes of the procedure.

Results:
Of 500 angiograms done over a nine-month period at a single center, 431 (86.2%) of cases were successfully performed via TRA. There was one case of temporary neurologic deficit in the TRA group, and none in the TFA group (n=1, 0.2% TRA vs. n=0, 0.05 TFA, p=0.8). Vascular access-site complications were lower in the TRA group than TFA (n=2, 0.4% TRA vs. n=2, 4.7% TFA, p=0.04). There was no difference in the number of cases successfully performed via TRA in the first half of the study compared with the second (n=215, 86.0% vs. n=216, 86.4%, p=0.90). Fluoroscopy time decreased from the first half of the study to the second half for TRA performance(5.0±3.9 min/vessel vs. 3.4±3.5 min/vessel, p<0.001), while TFA performance time remained unchanged (3.7±1.8 min/vessel vs. 3.5±1.4 min/vessel, p=0.69). The median fluoroscopy time for TRA became faster than TFA after 150 angiograms.

Conclusions:
Among angiograms performed during the first full year of “radial first” implementation, 86% were performed successfully using TRA. TRA efficiency continued to improve beyond the initial learning curve, exceeding that of TFA after 150 angiograms. Concerns about length of procedure or radiation exposure should not be barriers to TRA adoption.
Abstract P509: Signal Intensity in the Middle Cerebral Artery as a Practical and Feasible Index of Hemodynamic Insufficiency Due to Carotid Artery Stenosis
Authors: Mori Takahisa , Yoshioka Kazuhiro , Miyazaki Yuichi
Published: March 2021

Introduction:
Intracranial hemorrhage occasionally occurs after carotid revascularization in presents with hemodynamic insufficiency. Positron emission tomography is unavailable in most facilities, and a feasible index is required to identify high-risk patients. Reduced signal intensity (SI) of the middle cerebral artery (MCA) on magnetic resonance angiography (MRA) is associated with postoperative hyperperfusion.

Hypothesis:
Reduced signal intensity (SI) of the MCA on MRA is associated with decreased regional cerebral blood flow (rCBF) on single-photon emission CT (SPECT) and increased blood-sampling whole-brain oxygen extraction fraction (wb-OEF).

Methods:
We included patients who: 1) were admitted from 2015 to 2019 for carotid artery stenting (CAS), 2) MRA, and SPECT before CAS, and 3) examined the wb-OEF immediately before CAS. We measured bilateral MCA SI on MRA and defined the MCA relative SI as (SI in the affected MCA)/ (SI in the contralateral MCA). We defined the rCBF% as rCBF in the affected MCA territory against the ipsilateral cerebellum. Before CAS, we sampled blood, measured the arterial oxygen and the venous oxygen content in the dominant-sided jugular vein, and calculated the wb-OEF. We evaluated the correlation between the MCA relative SI, the MCA slow flow, the rCBF%, and the wb-OEF. We estimated the upper limits of the MCA relative SI for the rCBF% < 80% or wb-OEF ≥ 0.40 using the area under the curve (AUC) values derived from the receiver operating characteristic (ROC) curves.

Results:
During the study period, 150 patients met our inclusion criteria. The MCA relative SI was positively correlated with rCBF% and negatively with the wb-OEF. The ROC curve for the rCBF% < 80% showed that the upper limit of the relative SI was 0.77 (the sensitivity of 53.9%, the specificity of 83.9%, AUC of 0.723). The ROC curve for the wb-OEF ≥ 0.40 showed that the upper limit of the relative SI was 0.95 (the sensitivity of 67.7%, the specificity of 55.2%, AUC of 0.625).

Conclusion:
Reduced MCA SI on MRA ≤ 0.77 is a practical and feasible index of hemodynamic insufficiency, indicating the decreased rCBF and increased wb-OEF.
Abstract P510: Ct Angiographic Radiomics Signature Predicts Functional Outcome Following Endovascular Thrombectomy in Large Vessel Occlusion Stroke
Authors: Avery Emily W , Behland Jonas , Haider Stefan P , Zeevi Tal , Nguyen Cindy Khanh , Peshwe Krithika , Petersen Nils H , Falcone Guido J , Sansing Lauren H , Malhotra Ajay , Matouk Charles C , Sheth Kevin N , Payabvash Seyedmehdi
Published: March 2021

Purpose:
Endovascular thrombectomy (ET) is the standard of care in large vessel occlusion (LVO) stroke, with CTA and CT/MR perfusion guiding patient selection. We hypothesized that radiomics imaging features extracted from admission CTAs could predict post-ET outcome.

Methods:
We included patients with anterior circulation LVO who had ET at our institute, 01/2013–12/2019. We extracted 1116 radiomics features from each MCA supply territory. We applied and evaluated a framework of 6 feature selection techniques and 6 machine-learning classifiers for prediction of discharge and 3-month follow-up outcome, defined as favorable (modified Rankin score, mRS≤2) vs poor (mRS>2). Post-ET reperfusion success was determined by the modified thrombolysis in cerebral infarction (mTICI) scale. We used Bayesian optimization for hyperparameter tuning and performed 20 repetitions of 5-fold cross-validation, for which the average area under the receiver operating characteristic curve (AUC) across validation folds for each of our 36 feature-selection/machine-learning combinations was calculated.

Results:
501 patients (228 male) were included, with mean age 70.3±15.5 years, median NIH stroke score 15 (interquartile range=6–24), and occlusions in ICA (n=123), M1 (n=318), and/or M2 (n=154). Functional outcome was available for 496 patients at discharge and for 375 at 3-months. Best performing models combining NIHSS, age, gender, IV thrombolytic treatment, and post-ET mTICI achieved an average AUC of 0.82±0.05, while models trained on radiomics and mTICI achieved an AUC of 0.71±0.05.

Conclusion:
The combination of automatically extracted CTA radiomics features and post-ET reperfusion success (mTICI) can predict LVO stroke functional outcome – even without baseline clinical variables. Such models may guide treatment decisions by predicting outcome for various degrees of post-ET reperfusion and automating assessment of baseline stroke CTA scans.
Abstract P512: Immune Correlates of Functional Outcome in Acute Ischemic Stroke (AIS) Patients
Authors: Ortega-Gutierrez Santiago , Farooqui Mudassir , Zevallos Cynthia , Quispe-Orozco Darko , Dajles Andres , Mendez Ruiz Alan , Manzel kenneth , Dlouhy kathleen , Samaniego Edgar A , Derdeyn Colin P , Tranel Daniel , Karandikar Nitin , Ortega Sterling
Published: March 2021

Introduction:
Acute Ischemic Stroke (AIS) is one of the leading causes of disability and death in US. Although Endovascular Therapy (EVT) remains the mainstay therapy during acute phase for large vessel occlusions (LVOs), functional outcome varies among the treated patients. This ischemic injury results in an inflammatory response which plays an important role in the functional and neurological outcomes. We hypothesize that the early changes in the inflammatory response near the site of occlusion can be used as predictor of long-term neurofunctional decline

Methods:
AIS-LVO patients presenting to an academic comprehensive stroke center (CSC) within 24 hours from their last known well and undergoing EVT were included. Blood was collected proximal and distal to the thrombus during thrombectomy. Control samples were collected from the femoral artery and median cubital vein. Cytokine analysis and deep immune profiling was performed using a 20-parameter bead array and 13-parameter flow cytometer. Least Absolute Shrinkage and Selection Operator (LASSO) models were used for cell selection and correlation was evaluated for outcomes including mRS, NIHSS, MOCA and mortality, using R-software.

Results:
With 19 patients meeting the inclusion criteria, cytokine analysis revealed a significant increase in MMP and IFN-g, and decrease in GM-CSF, IL17, TNF-α, IL6, MIP-1a, and MIP-1b distal to clot. Flow cytometry analysis revealed a significant decrease in NK-T-cells, and CD8 T-cells counts and a relative increase in GM-CSF+ and IL17+ CD4 T-cells distal to clot. Immunological and neurological analysis revealed a correlation with CD4
+
IFN-γ
-
IL10
+
(r=0.7) & CD8
+
IFN-γ
-
GMCSF
+
(0.6) with mRS, and CD4
+
IFN-γ
-
IL10
+
(r=0.7), CD4+ IFN-γ
-
IL17
+
(r= -0.6), & CD8
+
IFN-γ
+
IL17
+
(r=0.7) cells with mortality.

Conclusion:
Our results indicate that local ischemia results in a hyperacute adaptive immune response at the site of occlusion. This immune response is predictive of functional outcome among AIS patients and is impactful in multiple ways, including the use of supportive therapy for patients with a poor functional trajectory and the use of immune-modulators at the site of ischemic injury.
Abstract P518: Intravascular Ultrasound Assisted Endovascular Revascularization in Patients With Subacute and Chronic Internal Carotid Artery Occlusions
Authors: Kumar Nitish F , Balasetti Vamshi , Pfeiffer Kimberly , French Brandi R , Gomez Camilo R , Siddiq Farhan , Qureshi Adnan I
Published: March 2021

Background:
Revascularization of subacute or chronic internal carotid artery occlusion is technically feasible in some patients but carotid revascularization procedure needs to be optimized to improve the clinical success of the procedure.

Objective:
To describe our experience using intravascular ultrasound (IVUS) as adjunct to carotid revascularization procedure in patients with subacute or chronic internal carotid artery occlusion.

Materials and Methods:
Endovascular recanalization was attempted in 7 patients with symptomatic internal carotid artery occlusions between 3 and 11 days of symptoms onset. Distal protection device was deployed in all the patients followed by advancement of IVUS catheter (Eagle Eye Gold, 20 MHZ Digital, s5 Imaging System, Volcano Corp.) to obtain gray-scale and virtual histology (VH) images at regions of interest. IVUS images used to categorize occlusion content as: dark green- fibrous; yellow/green- fibrofatty; white- calcified; red- necrotic lipid core plaque on images. Intravascular thrombus was diagnosed an echolucent, homogeneous, well-delineated, diaphragm-like intraluminal structure.

Results:
The occlusion was recanalized successfully in all of 7 patients with median age 67.4±7.5 years. IVUS demonstrated intravascular thrombus in 5 of 7 patients. Fibrous and fibrofatty constituents of plaque were seen in 5 of the 7 patients in whom VH was done. Calcification and lipid necrotic core each were seen in 3 of 5 patients.5 patients with large thrombus burden on IVUS were treated using aspiration thrombectomy. Six of seven patients underwent stent placement and one patient underwent primary angioplasty. 5 of 7 patients had modified Rankin Scale of 0-2 at follow up (3 weeks to 4 months post procedure).

Conclusions:
IVUS provided valuable information to optimize carotid revascularization procedure in patients with subacute or chronic internal carotid artery occlusion.
Abstract P520: Infarct Growth Rate is an Independent Predictor of Poor Outcome and Mortality After Mechanical Thrombectomy With Successful Reperfusion
Authors: Quispe-Orozco Darko , Sequeiros Joel M , Zevallos Cynthia , Farooqui Mudassir , Nguyen Cindy Khanh , Peshwe Krithika , Dajles Andres , Mendez Ruiz Alan , Kobsa Jessica , Prasad Ayush , Kodali Sreeja , Petersen Nils H , Ortega-Gutierrez Santiago
Published: March 2021

Introduction:
Despite treatment with mechanical thrombectomy (MT), some patients fail to regain functional independence at 90 days. The growth of the ischemic core varies across patients, and likely reflects differences in collateral flow and ischemic tolerance. In this study, we sought establish the optimal infarct growth rate (IGR) threshold to differentiate between slow and fast progressors and assess its ability to predict poor outcome.

Methods:
We retrospectively identified patients with anterior large-vessel occlusion (LVO) stroke with successful MT (mTICI ≥ 2b) at two comprehensive stroke centers. Final infarct volume (FIV) was calculated from post-MT Diffusion-weighted MRI. Assuming relative stability of the FIV after successful reperfusion, we defined IGR as [FIV (ml)] / [Time from stroke onset to reperfusion (hours)]. Good clinical outcome was defined as a modified Rankin scale score (mRS) ≤2. We used Receiver Operating Characteristics (ROC) analysis to calculate the optimal IGR threshold with high specificity for predicting a poor outcome. Multivariate logistic regression analysis was performed to evaluate the association of fast progressors (IGR ≥ 7.14 ml/h) on the poor functional outcome and mortality.

Results:
Of the 212 patients (age 68 ± 15, 51% female, NIHSS 15 ± 7) included, 110 (51.8%) patients had a poor outcome. The median IGR was significantly higher in patients with poor compared to good outcome (7 ml/h vs. 3.1 ml/h, p<0.001). An IGR ≥ 7.14 ml/h showed a sensitivity of 0.49 and a specificity of 0.7 to predict a poor outcome with an area under the ROC curve of 0.65 (95% CI, 0.58-0.73). IGR ≥ 7.14 ml/h was an independent predictor of poor outcome (OR 2.2, 95% CI 1.1-4.6, p=0.036) and mortality (OR 4.2, 95% CI 1.8-10.6, p=0.001) after adjusting for age, sex, atrial fibrillation, NIHSS and ASPECTS. Ordinal regression showed that the odds of having better outcomes decrease 60% in fast progressors (OR 0.40, 95% CI: 0.22-0.70, p=0.001) after adjusting for age, sex, atrial fibrillation, NIHSS, and ASPECTS.

Conclusions:
IGR is an independent predictor of poor outcome and mortality in patients with successful MT. Early identification of this population might help to institute therapeutic strategies of accelerating reperfusion and slowing the IGR.
Abstract P522: Endovascular Thrombectomy May Improve Excellent Outcomes in Severe Strokes With Isolated M2 Occlusions: A Pooled Cohort Analysis of the SELECT Study and the INSPIRE Registry
Authors: Sarraj Amrou , Bivard Andrew , Hassan Ameer E , Abraham Michael G , Pujara Deep , Day Arthur L , Blackburn Spiros , Campbell Bruce , Parsons Mark ,   On behalf of the SELECT and INSPIRE Investigators
Published: March 2021

Background:
The efficacy of endovascular thrombectomy (EVT) in M2 occlusions is uncertain.

Methods:
In a pooled patient level analysis of the prospective multicenter cohort study of imaging selection (SELECT) and the
INternational
Stroke Perfusion Imaging
REgistry
(INSPIRE) EVT outcomes were compared to medical management (MM) in M2 occlusions. Further, we assessed for potential treatment benefit in patients with higher stroke severity (NIHSS). The primary outcome was excellent outcome (mRS 0-1).

Results:
387 patients with isolated M2 occlusion (EVT 112, MM 275) met the inclusion criteria. Baseline NIHSS median (IQR) (EVT: 13 (9-19), MM: 10 (6-15), p<0.001) and infarct volume rCBF<30% (EVT 11 (4-24) vs MM: 8 (3-16), P=0.11). EVT was associated with a trend towards higher rates of excellent outcomes (48% vs 44%, aOR:2.80, 95% CI=0.95-8.25, p=0.061) with a shift towards better mRS outcomes (adj cOR: 2.57, 95% CI=1.11-5.94, p=0.028), and a reduction of neurological worsening (27% vs 47%, p<0.001) and numerically lower rates of sICH (4.5% vs 6.5%, p=0.43), and mortality (4.5% vs 9.5%, p=0.10). Assessing outcomes in NIHSS strata; there was no significant difference in excellent outcomes rates in patients with NIHSS ≤10 (EVT 62% vs MM 57%, aOR=2.18, 95% CI=0.30-15.73, p=0.44). In contrast, patients with NIHSS>10 had a trend towards higher excellent outcome rates outcomes with EVT (43%) vs MM (27%), aOR=3.11, 95% CI=0.81-11.95, p=0.098) as shown in figure 1.

Conclusion:
EVT may result in better rates of excellent outcomes in isolated M2 occlusions, especially those with more severe strokes who are more likely to have worse outcomes without emergent reperfusion.
Abstract P524: Impact of Intra-Procedural Workflow and Time Metrics of Establishing Fast Reperfusion on Clinical Outcomes in the ESCAPE-NA1 Trial
Authors: Kashani Nima , Marko Martha , Cimflova Petra , Singh Nishita , Ospel Johanna , Mayank Arnuv , Nogueira Raul , McTaggart Ryan , Demchuk Andrew M , Poppe Alexandre Y , Hill Michael D , MENON Bijoy K , GOYAL MAYANK , Almekhlafi Mohammed A
Published: March 2021

Background:
Time from imaging to establishing reperfusion is a major influencer of clinical outcomes and over the years thrombectomy techniques have evolved rapidly. This has led to improvements in achieving fast and complete reperfusion. We analyzed the impact of various intra-procedural techniques and tools on the speed of reperfusion and correlated procedural duration with probability of achieving good clinical outcomes.

Methods:
We analyzed intra-procedural time metrics and examined factors leading to delays during EVT. The relationship between outcome (mRS Scale) and procedural time from arterial puncture to time of achieving mTICI 2b-3 First Reperfusion (FRE) was modeled using logistic regression.

Results:
The various procedural time metrics are summarized in Figure 1. Every 10-minute increase in FRE time reduced the probability of achieving functional independence(90-day modified Rankin Scale 0-2) by 6.7% (P=0.021, adjusted). The medianFRE timewas 25min (IQR 17-39) and was significantly longer in patients with tandem occlusions(median 34min, p 0.0005). General anesthesia vs procedural sedation vs no sedation use did not significantly alter the FRE time (p = 0.1453). The use of BGC (54.2%) was nominally longer FRE (median 26min “IQR 18-38” vs 23ming, “IQR 16-38”; p 0.095)while the use of contact aspiration (n=213) vs retrievable stents (n=676) as the first approach was associated with a shorter FRE time (21min “IQR 14-35” vs 26 min “IQR18-40”, p =0.001).

Conclusions:
Puncture to first reperfusion time is a significant predictor of clinical outcome in theESCAPE-NA1 trial. Various procedural and anatomical factors influence this timemetric.

Figure:
Intra-Procedural workflow time metrics expressed in medians and 90th percentiles. The cumulative times are calculated for each major milestone in the procedure for upto three attempts. First reperfusion duration where TICI 2b was achieved is shown in comparison to other procedural time metrics.
Abstract P525: Endovascular Thrombectomy Outcomes in Transferred Octogenarians: A Multicenter Pooled Analysis
Authors: Greco Jonathan , Chen Michael , Hassan Ameer E , Goyal Nitin , Kamal Haris , Blackburn Spiros , Abraham Michael G , Day Arthur L , sitton clark , Requena Manuel , Grotta James c , Elijovich Lucas , Dannenbaum Mark J , Tekle Wondwossen , Hoit Daniel , Pujara Deep , Shaker Faris , Reddy Sujan S , Azher Aidan I , Abdulrazzak Mohammad Ammar , Mir Osman , Parsha Kaushik N , Martin-schild Sheryl , Tsivgoulis Georgios K , Alexandrov Andrei V , Ribo Marc , Sarraj Amrou
Published: March 2021

Background:
Acute ischemic strokes outcomes may be less favorable in elderly patients. Whether transferring octogenarians with large vessel occlusion (LVO) for endovascular thrombectomy (EVT) results in similar outcomes to younger patients is uncertain.

Methods:
A pooled cohort from 6 centers (Europe, US) from 1/2014 to 5/2020 of pts with (ICA, M1, M2) LVO transferred for EVT ≤ 24 hrs from LKW. Patients were stratified into < 80 vs ≥ 80 years old. We compared 90 day functional independence and safety outcomes and assessed for predictors of good outcome (mRS 0-2) and profound disability (mRS 5-6).

Results:
Of 1176 pts received EVT as transfers, 216 (18%) were octogenarians. Baseline NIHSS was higher in octogenarians [19 (14, 22) vs 17 (12, 21), p<0.001], while IV tPA (52% vs 54%, p=0.52) and time LKW to EVT center [285 (193, 537) vs 272 (190, 470) min, p=0.15] were similar. Functional independence rates were lower in patients ≥ 80 as compared to < 80 (26% vs 46%, aOR 0.50, 95%CI 0.34-0.75, p=0.001). sICH was similar (8.6 vs 9.9%, p=0.56), but octogenarians had significantly higher 90-day mortality (42% vs 17%, p<0.001).

Milder strokes (aOR 0.88, 95%CI 0.86-0.91, p<0.001), earlier presentation (aOR 0.95, 95%CI 0.91-0.98, p=0.004) and IV tPA (aOR 1.34, 95%CI 0.98-1.84, p=0.069) were associated with higher functional independence odds after EVT in octogenarians. Higher stroke severity (12% for each point, aOR=1.12, 95%CI 1.11-1.17-, p<0.001) and delayed reperfusion (3% for each additional hr, aOR 1.03, 95%CI 1.00-1.06, p=0.071) were associated with profound disability following EVT in octogenarians.

Conclusion:
EVT may be associated with lower independence rates in transferred octogenarians with LVO. Milder stroke severity, earlier presentation and IV thrombolysis increased the odds of good outcomes in octogenarians. Severe strokes and later treatment were associated with profound disability. Optimized selection and workflow is warranted in transferring elderly patients for EVT.
Abstract P529: Optimal Transport Scenario for Access to Endovascular Therapy With Consideration of Patient Outcomes and Cost
Authors: Wheaton Ashlee , VanBerkel Peter , Volders David , Fok Patrick T , Holodinsky Jessalyn K , Kamal Noreen
Published: March 2021

Introduction:
For an ischemic stroke patient whose onset geographically occurs outside of the catchment area of an EVT enabled facility and whose stroke is suspected to be caused by an occlusion in a large vessel of the brain, a transportation dilemma exists. Bypassing the nearest stroke hospital will delay tPA but expedite EVT. Not bypassing allows for confirmation of an LVO diagnosis before transfer to a CSC, but ultimately delays EVT. Air transportation can reduce a patient’s overall time to treatment. However, air transportation is costly.

Methods:
In a previously published model probability functions were developed to predict the outcome of a patient who screened positive for an LVO in the field based on how the patient was transported, Drip and Ship (PSC first, then CSC) or Mothership (direct to CSC). The addition of rotary wing transportation was conditionally applied to inter-facility transfer scenarios where it provided a time advantage. Transportation cost functions were created to include both fixed and variable costs as well as probabilities that model the likelihood of air transport providing a time advantage, air-worthy weather, and air resource availability. Both outcome and cost functions were developed for Mothership scenarios and for Drip and Ship scenarios including transfers via either ground or air depending on the conditional probabilities.

Results:
The figure shows the results of the model for location scenarios with 60 and 90 minutes between the thrombolysis only center and EVT capable center. Three efficiency scenarios are also shown in the figure: 1) both hospitals are efficient; 2) thrombolysis center is inefficient; and 3) both hospitals are inefficient.

Conclusions:
In some scenarios, both outcome and cost can be optimized to indicate whether Drip and Ship or Mothership is preferred. However, scenarios exist where outcome and cost are divergent. In divergent scenarios cost can be minimized at the expense of patient outcomes.
Abstract P535: Quality of Reperfusion and Clinical Outcome in ESCAPE-NA1 Trial
Authors: Cimflova Petra , Singh Nishita , Ospel Johanna , Marko Martha , Kashani Nima , Mayank Arnuv , Nogueira Raul G , McTaggart Ryan A , Demchuk Andrew M , Poppe Alexandre Y , MENON Bijoy K , Hill Michael D , GOYAL MAYANK , Almekhlafi Mohammed ,   ESCAPE-NA1 Investigators
Published: March 2021

Background:
We evaluated clinical outcome in relation to the degree of reperfusion in ESCAPE-NA1 trial.

Methods:
ESCAPE-NA1 was a multicenter, international randomized trial assessing the efficacy of nerinetide in ischemic stroke patients who underwent EVT within 12h from onset. Independent clinical outcome [90-days modified Rankin Scale (mRS) 0-2], excellent clinical outcome (90-days mRS 0-1), isolated subarachnoid hemorrhage with no parenchymal hemorrhage (iSAH) or symptomatic hemorrhage (sICH) on follow-up imaging, and death were compared between a treatment group and control group with respect to the level of reperfusion defined as mTICI. Univariable and multivariable logistic regression analyses were performed.

Results:
Data from 1090 patients were assessed. The occlusion locations were terminal ICA (18.3%), M1 MCA (61.8%,) M2 MCA (15.1%), other - e.g. M3 (3.7%). Final mTICI 0-1 was achieved in 5.5% of patients, mTICI 2a in 7.5%, mTICI 2b in 40.8%, mTICI 2c in 26.6% and mTICI 3 in 19.5%. Isolated SAH was present in 1.7% and sICH in 3%. There was no significant difference between the nerinetide and control groups in the reperfusion grade, presence of iSAH or sICH, or in clinical outcome. Odds of independent outcomes (mRS 0-2) and odds of excellent outcome (mRS 0-1) were significantly increasing with each improved reperfusion grade, Table 1. Sixty percent of patients with final mTICI 2b, 70% with mTICI 2c and 69% with mTICI 3 achieved good clinical outcome in comparison to 30% of patients with mTICI 0-2a. The incidence of iSAH was significantly lower in the NA1 arm (OR 0.28, 95%CI: 0.09-0.86, p=.027) adjusting for reperfusion status.

Conclusion:
Degrees of better reperfusion are strongly associated with better outcomes and reduced mortality. mTICI 2c-3 reperfusion should be a standard goal of EVT.