bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract W MP24: Modified Tibi (Thrombolysis in Brain Ischemia) Grading System for Assessment of Abnormal Residual Flow at Site of Intracranial Occlusion in Acute Ischemic Stroke
Authors: Ahmad Aftab , Sharma Vijay K , Basir Ghazala , Khan Khurshid , Alexandrov Andrei V , Tsivgoulis Georgios , Shuaib Ashfaq , Saqqur Maher
Published: July 2021

Background and purpose:
The intracranial blood flow at the site of arterial occlusion in acute ischemic stroke can be measured with Transracial Doppler (TCD) using the Thrombolysis in Brain Ischemia (TIBI) grading system. The TIBI ranges from 0 to 5, where 0 no flow and 5 normal flow. Our study’s aim is to modify the TIBI grading system in order to make it simple to implement in an acute stroke setting.

METHODS:
We classified Modified TIBI grading as: Grade 0- no flow, Grade 1- Bad flow: there is systolic flow but no diastolic flow or systolic flow with delayed acceleration and diastolic flow, Grade 2-Good flow: normal upstroke systolic flow and diastolic flow with decreased mean flow velocity compared to contralateral vessel by 30 %. We used the clotbust database to evaluate the modified TIBI scoring system. Poor long-term outcome was defined as modified rankin scale (MRS) score > 2.

RESULTS:
Total of 369 patients with acute ischemic stroke and intracranial arterial occlusion received IV r TPA. Median age was 71 years (IQ range: 58.7-79), Sex: women: 170(46.1%). Median NIHSS was 16 (IQ range: 12.7-2), 17/98 (17.3%) patients with modified TIBI 0, 73/205(35.6%) with modified TIBI 1 and 31/66( 47%) with modified TIBI 2 had achieved complete recanalization ( p value=0001). The multiple logistic regression model revealed Baseline higher NIHSS, systolic BP, glucose and modified TIBI grade 0 were independent negative predictor of complete recanalization. Patients with modified TIBI 3 had high probability of complete recanalization compared to TIBI 0(OR 3.14, CI 95%: 1.4-6.8, P=0.004).Poor outcome at 3 months (MRS>2) was found in 46/75(61.3%) patients with modified TIBI 0, 94/170(55.3%) with modified TIBI 1 and 19/38(33.3%) with modified TIBI 2(P value <0.004). On logistic model age, baseline NIHSS, glucose and TIBI 0 were independent negative predictors of good outcome.Although statistically insignificant but patients with modified TIBI 3 had a trend towards high probability of good functional outcome (OR: 1.73, CI 95%:0.73-4.12, p=0.20).

CONCLUSION:
Modified TIBI grading system is simplified version of TIBI grading and is easy to understand and apply clinically. It also predicts reliably the recanalization and functional outcome.
Abstract W MP31: Thrombotic and Hemorrhagic Complications After Pipeline Embolization - A Platelet Aggregation and Transcranial Doppler Study
Authors: Raychev Radoslav , Tateshima Satoshi , Vinuela Fernando , Jahan Reza , Gonzalez Nestor , Szeder Viktor , Bagude Amit , Konstas Angelos , Duckwiler Gary
Published: July 2021

In this study, we sought to determine the correlation between the pre-treatment platelet aggregation, and the respective occurrence of thrombotic and hemorrhagic complications after pipeline embolization device (PED) for treatment of intracranial aneurysms. In addition, we evaluated the cerebral hemodynamics and the presence of silent emboli after PED placement in some patients utilizing transcranial Doppler (TCD).

Methods:
We analyzed the clinical and imaging characteristics of 46 consecutive patients who underwent 48 PED procedures. All patients received double antiplatelet therapy with Clopidogrel 75mg and Aspirin 325mg daily for at least 3 days prior to the planned procedure. Platelet aggregation testing was performed in 41/48 (86%) procedures. Based on the initial ADP % inhibition, patients were divided in 3 groups in the present study: 1) poor responders: <50%, 2) satisfactory responders: 50-75%, and 3) over-responders: > 75%

Results:
Hemorrhagic complications requiring escalation of care occurred in 15% (7/48) of all procedures, including 3 patients with symptomatic ICH. 2/3 ICHs occurred in a remote vascular territory in reference to the treated aneurysm, one of which was fatal. Thrombotic complications occurred at a rate of 13% (6/48), of which 3 (9%) were symptomatic. Permanent complication-related morbidity and mortality at 6 months was 4% (2/48).

Of all patients with available platelet aggregation testing (n=41), 13 (31%) were poor Clopidogrel responders. Of those, 6 were switched to an alternative antiplatelet regimen. Thrombotic complications occurred mostly in the poor responders group who had no change in their regimen (27% vs. 4%; p=0.05).

Intracranial hemorrhage occurred entirely in the over-responders group, (0% vs. 14%; p=0.08). None of the TCD demonstrated presence of silent emboli. In addition, 10/11 patients had elevated flow velocities after the PED placement.

Conclusions:

1. Pre-treatment Clopidogrel response, measured by ADP % inhibition may predict thrombotic and/or hemorrhagic complications after PED placement.

2. Distal embolization likely occurs mostly during, but not after the procedure as suggested by the TCD data in this study.
Abstract W MP41: Potentiation of Gaba-Mediated Synaptic Inhibition in the Recovery Phase: A Novel Therapeutic Target for Stroke
Authors: Hiu Takeshi , Bliss Tonya , Paz Jeanne , Wang Eric , Farzampour Zoya , Olson Andrew , Micheva Kristina , Wang Gordon , Tran Kevin , Manley Nathan , Lemmens Robin , Nishiyama Yasuhiro , Arac Ahmet , Hamilton Scott , O’Rourke Nancy , Smith Stephen , Huguenard John , Steinberg Gary
Published: July 2021

Background:
Stroke is a major cause of disability yet pharmacotherapy targeting the recovery phase is lacking. Cortical circuit reorganization adjacent to the stroke site promotes recovery, thus elucidating mechanisms that promote this plasticity could lead to new therapeutics.
Tonic
neuronal inhibition, mediated by extrasynaptic GABA
A
receptors,inhibits post-stroke recovery. However, effects of
phasic
(synaptic) GABA signaling - which promotes plasticity during development - are unknown. Here we use a combined approach of i) array tomography to determine the composition of GABA synapses in the post-stroke mouse brain, ii) electrophysiology to determine whether stroke leads to functional changes in GABA-mediated phasic inhibition, and (iii) treatment with zolpidem, an FDA-approved GABA agonist, to modulate recovery.

Results:
We found, using array tomography, a 1.7-fold increase in the number of GABAergic synapses containing the α1 receptor subunit in layer 5 of the peri-infarct cortex (synapse number/μm
3
: 0.039±0.006 (control) vs 0.064±0.006 (stroke); P<0.01), but not in layer 2/3. There was an associated increase in spontaneous inhibitory post-synaptic currents (sIPSC) specific to layer 5 pyramidal neurons (sIPSC charge (fC): -403±27.8 (control) vs -724±166 (stroke); p=0.03). This effect was transient, occurring during the onset of functional recovery. To test whether the increased phasic inhibitory GABAergic signaling promotes stroke recovery, we treated animals with zolpidem, an agonist with high affinity for α1 subunit-containing GABA
A
receptors. Low dose zolpidem increased GABA
A
phasic signaling in layer 5 pyramidal cells and notably increased the rate and extent of behavioral recovery without altering infarct size.

Conclusions:
These data provide the first evidence that enhanced GABA
A
-mediated synaptic activity during the recovery phase improves stroke outcome. These data identify modulation of phasic GABA signaling as a novel therapeutic strategy for stroke, indicate zolpidem as a potential drug to improve recovery, and underscore the necessity to distinguish the role of tonic and phasic GABA inhibition in stroke recovery.
Abstract W MP6: Pre-treatment Neuroimaging Is Critical to Identify Acute Stroke Patients With Large Infarcts Unlikely to Respond to Endovascular Therapy
Authors: Frei Don , Yoo Albert , Heck Donald , Hellinger Frank , McCollom Vance , Fiorella David , Turk Aquilla , Malisch Tim , Zaidat Osama , Alexander Michael , Devlin Tom , Levy Elad , Shah Qaisar , Hui Ferdinand , Goyal Mayank , Ghodke Raj , Shaibani Ali , Harrigan Mark , Jovin Tudor , Madison Michael , Chaudhry Zeshan , Gonzalez Ramon , Barraza Leticia , Bose Arani , Sit Siu Po ,   START Investigators
Published: July 2021

Purpose:
The Penumbra START Trial was a multi-center, prospective trial with an aim of testing if core infarct size on pre-treatment neuroimaging predicts clinical response to IA stroke therapy. Presented herein are final results of this study.

Methods:
As prespecified, infarcts were trichotomized into small [lesion volume <50 cc (CTP, DWI) or ASPECTS 8-10 (CTA)], medium (volume 50-100 cc or ASPECTS 5-7) or large (volume >100 cc or ASPECTS 0-4). In total, 146 patients were enrolled at 27 centers, including 115 patients meeting study criteria. Core infarct volumes were tiered by ranking imaging results by DWI > CTP > CTA.

Results:
Mean age was 66. Median NIHSS score was 19. Overall rate of TICI 2b-3 revascularization was 71% (post vs pre-procedure
p
<0.0001). Forty-five percent of patients had a 90-day good outcome (mRS ≤2); 27% died. Core infarct volumes were 24% small, 52% medium and 24% large; the number of patients for each imaging modality was 5% DWI, 38% CTP and 57% CTA. In tiered volume analysis, the good outcome rate was 68% in small, 46% in medium and 17% in large infarcts (
p
=0.0004), despite similar recanalization rates (74% small, 73% medium, 64% large,
p
=0.4186). Patients with large infarcts had significantly higher admission NIHSS (
p
=0.00782). Within 24 hours of intervention, the procedural SAE rate was 22% in small, 27% in medium and 46% in large infarcts (
p
=0.0497). Mortality and sICH rates also showed relationships with infarct volumes (11% small, 23% medium, 50% large,
p
=0.0011, and 4% small, 7% medium, 21% large,
p
=0.0245, respectively).

Conclusion:
Pre-treatment neuroimaging is important to identify patients with large infarcts who are less likely to have favorable outcomes and more likely to suffer mortality, sICH and procedural SAEs. These findings support the use of stringent imaging criteria in patient selection.
Abstract W MP7: Predictors and Implications of Capacity to Provide Informed Consent for Acute Ischemic Stroke Treatment Trials
Authors: Indupuru Hari Kishan R , Shen Loren , Jacobs Amber N , Cai Chunyan , Grotta James C , Barreto Andrew D
Published: July 2021

Background and objectives:
Enrollment into AIS trials has always been limited by the ability of the patient to give informed consent or the availability of a Legally Authorized Representative (LAR) in decision making capacity on behalf of the patient. In this analysis we try to identify the factors contributing to an acute ischemic stroke (AIS) patient’s inability to give informed consent. We hypothesized that clinical features and demographics would differ between those patients with and without capacity to consent.

Methods:
This analysis includes patients who enrolled into the coordinating center of the prospective, randomized ARTSS-2 clinical trial (Argatroban + TPA for acute ischemic stroke) and also screen failures due to inability to consent. Data is collected prospectively in the study screening log. The data collected included age, gender, race, NIHSS, lesion location, ER arrival time and mode of consent (self-consent, LAR-consent and unable to consent).

Results:
Between 12/11 and 06/13, a total of 33 acute ischemic stroke patients received IV-tPA and were eligible for the ARTSS-2 study. While 19 were enrolled, 14/33 (42.4%) were otherwise eligible, but not enrolled due to inability to self-consent and no LAR present. Patients not enrolled due to lack of capacity to consent and without LAR present tended to have higher median NIHSS scores and greater proportions of drowsiness and aphasia compared to the other groups (see table).

Conclusion:
Approximately 2 in 5 AIS patients are not eligible for AIS clinical trials based solely on their lack of capacity for informed consent. It is remains ethically imperative that current clinical trials as well as future study designs address this disregarded group of patients who deserve the right to be able to participate in research. Addressing this group of patients through exception from informed consent (EFIC) will both extend research to all stroke patients, but also greatly enhance AIS research.
Abstract W MP9: Early Reperfusion with a Stentriever Device: A First Step to Superior Outcomes in TREVO2
Authors: Liebeskind David S , Scalzo Fabien , Sanossian Nerses , Xiang Bin , Gupta Rishi , Jovin Tudor G , Albers Gregory W , Lutsep Helmi L , Smith Wade S , Nogueira Raul G ,   for the TREVO2 Investigators
Published: July 2021

Background:
TREVO2 showed better outcomes after thrombectomy with the Trevo stentriever compared to Merci. We studied the impact of early reperfusion up to the first pass to explore the impact of device deployment on subsequent outcomes.

Methods:
Reperfusion during stentriever deployment and after the first pass in both arms (Merci and Trevo) of TREVO2 was quantified by cerebral blood volume (CBV) delivered to the downstream territory using perfusion angiography (perfAngio) software. Automatic, normalized extraction of CBV distal to anterior circulation occlusions was obtained from AP projections during arterial phase. CBV during deployment, after the first pass and sum of CBV up to the first pass (Σ CBV) were analyzed with respect to angiographic and clinical outcomes.

Results:
CBV was measured from DSA in 83 (34 Trevo, 49 Merci) occlusions in TREVO2. Clinical variables of this cohort were similar between device arms and with respect to others in the trial. During stentriever deployment, 29/34 cases demonstrated delivery of blood volume to downstream territory, averaging about 10% of the amount delivered after the first pass. Change in CBV from deployment to the first pass in 26/29 cases showed a further increase in 15 and decrease in 11, with re-occlusion in 4. CBV only after the first pass did not differ between Merci and Trevo (p=NS). CBV after first pass (p=0.06) and Σ CBV (p=0.03) both predict successful revascularization and demonstrate a moderate correlation with the time to sustained TICI 2a flow. Logistic regression analysis revealed that Σ CBV is a predictor of good clinical outcome (mRS 0-2) at day 90 (p=0.08) and use of Trevo further impacts outcome.

Conclusions:
Stentriever deployment achieves delivery of blood volume to the ischemic bed downstream. The amount of CBV delivered up to the first pass influences revascularization and good clinical outcomes.
Abstract W P108: The Burden and Topographic Distribution of Intracranial Atherosclerosis Predict Stroke Recurrence: A Longitudinal Study of Acute Ischemic Stroke Patients
Authors: Kim Byung-Su , Kim Gyeong-Moon , Bang Oh Young , Lee Kwang Ho , Chung Chin-Sang
Published: July 2021

Introduction:
To date, it remains unclear whether the burden and topographic distribution of intracranial atherosclerosis (ICAS) predict subsequent stroke event.

Hypothesis:
We assessed the hypothesis that the presence of advanced ICAS at the baseline is an independent biomarker to predict future stroke recurrence among acute ischemic stroke patients.

Methods:
A total of 446 consecutive patients with ischemic stroke or transient ischemic attack (TIA) were included in this study. Cox proportional regression model was used to examine the association between the burden and topographic distribution of ICAS and subsequent ischemic stroke or TIA. Using the MRA findings at the baseline, we classified patients into 3 groups by the number of ICAS: 1) none (n=277); 2) single (n=88); and 3) two or more (n=81), and into 4 groups by the distribution of ICAS: 1) none (n=277); 2) anterior circulation territory (n=89); 3) posterior circulation territory (n=48); and 4) both circulation territories (n=32), respectively.

Results and Conclusions:
The recurrence rate of ischemic stroke or TIA was 10.8% (n=48) over a median 4.6 years of follow-up. The presence of two or more ICAS (adjusted hazard ratio [HR]: 2.54, 95% CI: 1.31-4.92) and ICAS located in both circulation territories (HR: 3.27, 95% CI: 1.38-7.73) were independently associated with an increased risk of recurrence of ischemic stroke or TIA, after adjustment of vascular risk factors and secondary prevention medication. In conclusion, our findings suggest that advanced ICAS in acute ischemic stroke patients could be an independent predictor for recurrence of ischemic stroke or TIA.
Abstract W P11: A Clinical Scale to Predict Futile Arterial Recanalization in Acute Stroke Patients with Anterior Circulation Arterial Occlusion Treated with Endovascular Therapies.
Authors: Perez de la Ossa Natalia , Hernández-Pérez Maria , Millán Monica , Gomis Meritxell , López-Cancio Elena , Dorado Laura , García-Bermejo Pablo , Castaño Carlos , Dávalos Antoni
Published: July 2021

Introduction:
Futile arterial recanalization (FAR), considered as a lack of functional recovery despite complete recanalization, is observed in up to 30-50% of acute stroke patients treated with endovascular therapy. We aimed to develop a prognostic scale based on baseline clinical and radiological factors to predict FAR.

Methods:
Prospective analysis of consecutive stroke patients with anterior circulation occlusion treated with endovascular therapy (97% mechanical thrombectomy with stent-retrievers). Complete recanalization was considered as a TICI 2b-3. FAR was defined as a modified Rankin scale >2 at 90 days in patients with complete recanalization. Baseline factors associated with FAR were detected on univariate analysis and were used to compose the predictive scale.

Results:
From a total of 229 patients with anterior arterial occlusion, 166 (72.5%) achieved complete recanalization. FAR was observed in 80/166 (48.2%). Factors significantly associated with FAR were included to compose the predictive scale as follow: Age (scoring 0 if ≤70 and 1 if >70 years old), history of diabetes mellitus (0 if absent, 1 if present), history of hypertension (0 if absent, 1 if present), NIHSS (1 if NIHSS ≤10, 2 if NIHSS 10-19, 3 if NIHSS>19), ASPECTS (1 if ASPECTS 9-10, 2 if ASPECTS 7-8, 3 if ASPECTS<7) and i.v tPA use (0 if yes, 1 if not). The higher the scale score, the higher the risk of FAR (Figure). The scale showed a good predictive value of FAR (c-statistics 0.71). A scale score <5 was associated with a low rate of FAR (25%) whereas a score >7 increased FAR up to 86%.

Conclusion:
We developed a simple scale that can easily predict futile arterial recanalization (FAR) in stroke patients with large arterial occlusion treated with endovascular therapies. A larger validation study is necessary to confirm the utility of this predictive scale.
Abstract W P130: Relationship Between Risk Factor Control and Vascular Events in the Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS) Trial
Authors: Turan Tanya N , Nizam Azhar , Lynn Michael J , Montgomery Jean , Derdeyn Colin P , Fiorella David , Lane Bethany , Janis Scott , Chimowitz Marc I ,   SAMMPRIS Investigators
Published: July 2021

Background and Purpose:
Symptomatic intracranial stenosis patients with poorly controlled cholesterol and blood pressure had an increased risk of vascular events in WASID. Therefore, SAMMPRIS aggressive medical management protocols targeted these risk factors. We sought to determine if intensive risk factor control in SAMMPRIS resulted in lower risk of vascular events during follow-up.

Methods:
Data on 227 SAMMPRIS patients randomized to aggressive medical management alone were used for these analyses. Vascular risk factors were recorded at baseline, 30 days, and every 4 months. Additional follow-up and close-out visit data were also included. For each patient, values for all risk factor measures (from baseline until the time of an event) were averaged and dichotomized based on the risk factor target. Time to event curves for a vascular event (stroke, MI, and vascular death) were compared between subjects with and without risk factor control using the log-rank test and hazard ratios were calculated with Cox proportional hazards regression.

Results:
The univariate analyses are shown in the table. Subjects with mean follow-up SBP < 140 mm Hg (< 130 for diabetics), LDL < 70 mg/dL, and at least moderate exercise had lower risk of vascular events compared to those who did not achieve those targets. Control of other risk factors (HgA1c, smoking, non-HDL, and Body Mass Index) did not have a significant impact on outcome.

Conclusions:
Well controlled SBP and LDL during follow-up were predictors of lower vascular events in SAMMPRIS, confirming that SBP and LDL should be aggressively treated in patients with intracranial stenosis to prevent future vascular events. Exercise participation was also associated with fewer vascular events and should be strongly encouraged.
Abstract W P132: Cephalometric Features of Moyamoya Disease: A Case Control Study
Authors: Gilani Waqas I , Gilani Sarwat I , Adil Malik M , Qureshi Adnan I
Published: July 2021

Background:
Moyamoya disease is highly prevalent among patients with syndromes that have unique cephalometric characteristics such as Down syndrome. We performed a case control study to investigate the relationship between cephalometric parameters and Moyamoya disease.

Methods:
Patients [aged 16-82 years] with angiographically confirmed Moyamoya disease who underwent cranial CT scan were analyzed. We identified three controls for each patient who were matched for age (±1 year), gender, and race (white or African American). The fronto-occipital diameter, bi-parietal diameter, and distance between bregma and occiput were measured from the head CT scans of cases and controls. The cephalic index was calculated by determining the ratio between bi-parietal diameter and fronto-occipital diameter and multiplying the value by 100.

Results:
A total of 13 cases of Moyamoya disease and 39 controls were analyzed. The stage of Moyamoya disease in cases was as follows: stage 1 (n=0), stage 2 (n=1), stage 3 (n=4), stage 4 (n=2), stage 5 (n=5) and stage 6 (n=1). There was a significantly greater bi-parietal diameter in Moyamoya disease patients compared with controls (141.5±3.7 mm versus 136.9±5.4 mm, p=0.007). There was a significantly greater fronto-occipital diameter in Moyamoya disease patients compared with controls (186.5±6.5 mm versus 180.2±8.7mm, p=0.02). The distance between bregma and occiput was shorter among cases compared with controls (81.1±6.2 versus 87.5±7.0, p=0.01).

Conclusions:
We observed an association between cephalometric parameters and Moyamoya disease. Further study of the unique cephalometric characteristics among Moyamoya disease patients may provide additional insight into disease occurrence in white and African American populations.
Abstract W P134: Abdominal Obesity and Low Ankle-Brachial Index Are Simple Physical Exam Signs Independently Predicting Severe Intracranial Atherosclerosis
Authors: Barros Alexandre D , Reis Carolina C , Jesus Adriano A , Fernandes Rodrigo D , Ferreira Isadora L , Fonseca Luana F , Resende Lucas L , Lordelo Morgana J , Barreto-Neto Nestor J , Ventura Lais M , Andrade Alisson L , Gonçalves Beatriz M , Martins-Neto Gentil P , Jesus Pedro A , Oliveira-Filho Jamary
Published: July 2021

Background:
The investigation of ischemic stroke etiology is commonly limited to the heart and extracranial vessels. However, the diagnosis of intracranial stenosis may carry important therapeutic implications. We aimed to determine the prevalence of intracranial stenosis and compare the predictors of intracranial and extracranial stenosis in patients with ischemic stroke.

Methods:
Consecutive patients admitted to a university-based outpatient stroke clinic were submitted to 64-slice CT angiography (CTA) of the intracranial and extracranial brain vessels. Clinical, demographic and laboratory characteristics were compared between patients with or without a critical (>70%) intracranial or extracranial arterial stenosis. Ankle-brachial index (ABI) was measured to quantify peripheral arterial disease, defined by a low ABI (<=0.9). Multivariable logistic regression analysis was performed including variables with a possible (P<0.1) association in univarible analyses, searching for predictors of intracranial and extracranial stenosis.

Results:
One hundred-five patients were studied, mean age 59 +/- 14 years, 55% female. Intracranial stenosis occurred in 13% of the sample, while extracranial stenosis occurred in 14%. Clinical characteristics such as age, sex and major cerebrovascular risk factors did not discriminate between patients with or without intracranial stenosis. No association was found between intracranial and extracranial stenosis. The predictors of intracranial stenosis in the multivariable analysis were low ABI (OR=21.2; 95% CI 1.8-250.0) and abdominal circumference (OR=1.11 for every 1 cm increase; 95% CI=1.01-1.22), while the only predictor of extracranial stenosis was smoking history (OR 1.02 for every 1 pack-year; 95% CI 1.01-1.04). Low ABI was the best screening tool for intracranial stenosis (sensitivity 89%, specificity 70%, positive predictive value 32%, negative predictive value 98%).

Conclusion:
Classical cerebrovascular risk factors do not discriminate between patients with or without intracranial stenosis. Abdominal circumference and ABI may be useful clinical screening tools for intracranial stenosis.
Abstract W P137: Blood Viscosity Determinants and Clinical Outcome after Ischemic Stroke
Authors: Nishimura Kazutaka , Koga Masatoshi , Nagatsuka Kazuyuki , Minematsu Kazuo , Toyoda Kazunori
Published: July 2021

Backgrounds and Purposes:
Both hematocrit (Hct) and fibrinogen (Fbg) are major blood viscosity determinants. Blood viscosity is known to be an important regulator of cerebral blood flow. However, the relationships of Hct and Fbg with clinical outcome after ischemic stroke are controversial. We aimed to elucidate association of these viscosity determinants with clinical outcome.

Methods:
Consecutive patients with acute ischemic stroke admitted to our hospital within 7 days after the onset of symptoms between January 2011 and March 2013 were retrospectively studied from our single-center prospective stroke database. Plasma levels of Hct and Fbg were measured on admission. Yield shear stress (YSS) was calculated using the following equation: 13.5 (10
-12
) (Fbg)
2
(Hct-6)
3
. Initial stroke severity was assessed using the National Institutes of Health Stroke Scale (NIHSS). Favorable outcome was defined as the modified Rankin Scale (mRS) 0 or 1 at 3 months.

Results:
Of 1322 consecutive inpatients, 311 with premorbid mRS 2-5 and 139 with incomplete clinical data were excluded, and the remaining 872 were studied. Patients who had favorable outcome were younger (70±12 vs. 74±11, p<0.001), more commonly male (69.1 vs. 58.3 %, p=0.001), had lower NIHSS (median 2 vs. 9, p<0.001),had more hypertension (57.6 vs. 42.4 %, p=0.01) and less frequently had atrial fibrillation (21.4 vs. 37.5 %, p<0.001) than those without. Hct was 40.6±4.9 % in patients with favorable outcome and 39.2±5.4 % in those without (p<0.001). Fbg concentration was 332±74 mg/dl and 354±84 mg/dl (p<0.001), respectively, and YSS was 0.069±0.004 and 0.071±0.005 (p=0.44). Fbg (per 10 mg/dl, OR, 0.96; 95% CI, 0.94-0.98; p<0.001) and YSS (per 0.01, OR, 0.96; 95% CI, 0.92-0.99; p=0.002) remained independently significant to predict favorable outcome after adjustment for sex, age, comorbid disease and NIHSS, but Hct was not (per 1mg/dl; OR, 1.00; 95% CI, 0.97-1.04; p=0.69)

Conclusions:
Lower fibrinogen and lower yield shear stress, rather than hematocrit, were independently associated with favorable outcome in acute ischemic stroke.
Abstract W P151: Aging is Associated With Progressive Insufficiency of Circle of Willis Collaterals in Humans
Authors: Mokhtari Sepideh , Saeed Umair , Barber Sean M , Zhang Yi J , Klucznik Richard P , Diaz Orlando , Volpi John J
Published: July 2021

Introduction:
Increasing age is the single largest non-modifiable risk factor for ischemic stroke. Recent studies have shown that increasing age is associated with inadequacy of leptomeningeal collaterals, and aging has been shown to cause a progressive decline in the number and diameter of collateral vessels in experimental mice, resulting in an increased collateral resistance and an enhanced stroke severity.

Hypothesis:
Aging leads to progressive loss of Circle of Willis collateral vessels in humans.

Method:
We studied a retrospective, consecutive series of 167 women and 112 men undergoing cerebral angiography for any reason. A blinded investigator scored the Circle of Willis collaterals for each angiogram using a scoring system of 0 - 2 for each collateral (0 = absent, 1 = hypo-plastic, 2 = robust) for a total score of 0 - 14. Collaterals scored included the bilateral A1 segments of the anterior cerebral arteries, bilateral P1 segments of the posterior cerebral arteries, bilateral posterior communicating arteries, and the anterior communicating artery. We compared the number of collaterals based on age, gender, and race as well as history of prior infarct, aneurysm, smoking, hypertension, diabetes, and obesity.

Results:
Females had significantly more collaterals than men (p = 0.04)
.
The average collateral score for males and females was 10.77 and 11.14, respectively. Patients younger than 60 years of age had a significantly higher number of collaterals (average collateral score, 11.54) compared with patients older than 60 (average collateral score, 10.47; p = 1.59 x 10
-9
). Females exhibited a greater loss of collaterals with advancing age (p = 3.53 x 10
-5
) than men (p = 0.00016). Data was subjected to the Dunn-Bonferroni corrected t-test for preplanned comparisons or the Student t-test.

Conclusion:
Based on our study, patients younger than 60 years are significantly more likely to have an angiographically-complete Circle of Willis. The underlying mechanism for this effect in humans is uncertain and the subject of a future study.
Abstract W P153: Parental History of Stroke and Incident Atrial Fibrillation According to Blood Pressure Category in a General Urban Population: The Suita Study
Authors: Kokubo Yoshihiro , Watanabe Makoto , Kobayashi Takashi , Kamakura Shiro , Aiba Takeshi , Kusano Kengo , Kawanishi Katsuyuki , Miyamoto Yoshihiro
Published: July 2021

Background and purpose:
No prospective study has examined the relation between a parental history of stroke and the incidence of atrial fibrillation (AF) in a general population. We assessed the hypothesis that a parental history of stroke is associated with an increased risk of incident AF according to blood pressure (BP) category in a general population.

Methods:
A total of 6,918 participants (30 to 84 years old) initially free of AF were prospectively followed up for incident AF in the Suita Study. Standard 12-lead electrocardiograms were obtained from all subjects in the supine position. Each record was coded independently by 2 well-trained physicians using the Minnesota Code. Participants were diagnosed with AF if AF or atrial flutter was present on electrocardiograms obtained during a biannual routine health examination or if AF was indicated as a present illness by either annual questionnaires responses or participants' medical records. Well-trained nurses obtained information on parental history of stroke and on the participants' lifestyle. BPs were taken as the average of the second and third measurements. The category of systolic BP (SBP) was defined by the following criteria: normal SBP (<120 mm Hg), systolic prehypertension (120-139 mm Hg), and systolic hypertension (≥140 mm Hg and/or antihypertensive medications). Cox proportional hazard ratios (HRs) and 95% confidence intervals (CIs) were analyzed after adjusting for age, sex, body mass index, BP categories, diabetes, hyperlipidemia, smoking, and drinking status at baseline.

Results:
In 87,341 person-years of follow-up, 245 incident AF events occurred. A parental history of stroke was significance to the incidence of AF in men (adjusted HR, 1.47; 95% CIs, 1.03-2.10). Compared with normal SBP subjects without a parental history of stroke, the adjusted HRs (95% CIs) of incident AF in systolic hypertensive subjects were 2.18 (1.36-3.51) and 1.50 (1.01-2.23) for those with and without a parental history of stroke (P for interaction between parental history of stroke and SBP = 0.06).

Conclusions:
A parental history of stroke is a predictor of incident AF among systolic hypertensive subjects. For persons with a parental history of stroke, BP control would be important for AF prevention.
Abstract W P17: Factors Associated With DWI Lesion Growth After Endovascular Therapy for Acute Ischemic Stroke
Authors: Man Shumei , Hussain M. Shazam , Wisco Dolora , Cheng-ching Esteban , Osanai Toshiya , Katzan Irene , Uchino Ken
Published: July 2021

Background:
The factors impacting infarct evolution after intra-arterial(IA) intervention for acute ischemic stroke remain uncertain. We studied the infarct evolution on MRI DWI among acute stroke patients who underwent IA therapy.

Methods:
We reviewed the early ischemic stroke imaging database at Cleveland Clinic Cerebrovascular Center for those undergoing IA therapy in anterior circulation from 2009 to 2012. Patients with both pre-treatment and follow-up MRI were included. Infarct volume was measured on initial and follow-up DWI by region of interest demarcation. Patients were grouped into quartiles by infarct growth from initial to follow-up. Outcome were defined as modified Rankin Score 0-2 at 30 days.

Results:
Among the 76 patients, the median (range) infarct growth of four quartiles were 0.5 cc (-19.1-4.2), 13.8 cc (4.8-25.8), 38.8 cc (28.0-77.6), and 166.3 cc (78.0-314.5). Baseline characteristics of age, gender, race, diabetes, and hypertension were similar among groups except more smokers (p=0.017) and fewer patients on anticoagulation or antiplatelet agents in large-growth group (p=0.049). Compared to No-growth group (Quartile 1), large-growth group (Quartile 4) had more Hyperdense M1 MCA sign ( 26.3% vs 73.7%, p=0.004), larger initial ischemic lesion measured by CT ASPECT (p=0.002) and DWI volume (p=0.012), and absence of full collaterals on CTA ( 36.8% vs 0, p=0.004). There was a trend of lower recanalization rate in large-growth group (73.7% vs 47.4%, p=0.097). With the increment of infarct growth, there is a decrement in favorable outcomes (mRS 0-2) at 30 days: 42%, 37%, 26% and 10.5% (p=0.027).

Conclusion:
Infarct growth after IA therapy determines outcome. Initial ischemic lesion size, collaterals, and hyperdense vessel sign are associated with infarct growth.
Abstract W P177: Direct to CT: Overcoming Barriers to Reduce Door to Needle times in Acute Stroke Patients
Authors: Coote Skye , Frost Tanya , Singhal Shaloo , Bladin Chris , Gilligan Amanda
Published: July 2021

Background:
Taking acute stroke patients direct from triage to the CT scanner can reduce thrombolysis treatment times, which can improve patient outcomes. In May 2013, Box Hill Hospital introduced a Direct to CT policy for acute stroke patients who are called through as a Code Stroke by the ambulance service within business hours (8am-4.30pm) Monday to Friday.

Method:
We performed a prospective study comparing door-to-CT times (DTCT) and door-to-needle (DTN) times pre- and post-implementation of Direct to CT, and examined patient characteristics, Emergency Department (ED) presentation time, adverse effects, protocol violations and patient outcomes. Delays in treatment, enablers and barriers to treatment were also examined.

Results:
There was no statistical difference in demographics or clinical factors in patients who presented pre- (January-April, n=21) or post- Direct to CT (May-July, n=29). However, a reduction in median DTCT times (27 mins vs. 16 mins, p=0.01) and DTN times (97 mins vs. 52 mins, p<0.001) was seen. There was no increase in thrombolysed mimics (4.8% vs. 3.4%, p=0.82), protocol violations (9.5% vs. 0%, p=0.17) or adverse outcomes (33% vs. 35%, p=0.93) in patients taken Direct to CT. There was no difference in patient outcomes, however the current study size is small. Numerous barriers to Direct to CT were identified within four categories: pre-hospital, ED, CT and the stroke team, and issues included: lack of paramedic intravenous cannulation, ED resources, and stroke team indecisions; some of which are ongoing and are taking considerable time and efforts to overcome.

Conclusions:
Taking patients Direct to CT has significantly reduced time to treatment and further improvements may be achieved through resolution of identified barriers.
Abstract W P180: Sex Differences in Acute Stroke Evaluation
Authors: Chee Bryant H , Raman Rema , Ernstrom Karin , Meyer Dawn M , Meyer Brett C , Hemmen Thomas M , Guzik Amy K
Published: July 2021

Introduction:
Prompt acute stroke evaluation is essential for optimal treatment. Women may receive delayed evaluation and treatment; consistent data is unavailable. We analyzed sex differences in acute stroke evaluation.

Methods:
We evaluated consecutive Code Stroke patients from the UCSD SPOTRIAS database, excluding inpatients. Subgroups included acute ischemic stroke (AIS) and IV r-tPA treated patients. Wilcoxon and Fisher’s Exact Test compared baseline variables between sexes. Times from onset to arrival, arrival to: stroke code, neurological exam, brain imaging, laboratory, decision, and treatment were compared between sexes using linear regression, adjusting for pre-specified covariates: age, smoking, atrial fibrillation, hypertension, glucose, baseline NIHSS, pre-stroke mRS, and onset to arrival time. Multivariable logistic regression models evaluated 90 day mRS, adjusted as above. (Good outcome: mRS 0-2)

Results:
Of 3,214 patients (48.3% female), women were older (p<0.0001), with more atrial fibrillation (p<0.01), and higher pre-stroke mRS (p<0.0001) compared to men. Smoking history was more common in men in all analyses (p<0.0001). Evaluation times and 90-day outcomes were similar, except women had longer arrival to neurological exam times (41.5 ± 52.8 min vs. 37.5 ± 68.9 min; p=0.014). In total, 1,476 patients had AIS (45.8% female). Of all women with Code Strokes, 43.5% were diagnosed with AIS while 48.1% of men were diagnosed. In the AIS subset, evaluation times were not significantly different, though women with AIS were more likely to have poor outcome after adjusting for pre-specified covariates (54.5% vs. 39.4%, p=0.017). There were 532 patients diagnosed with AIS and treated with tPA (49.8% female). There were no significant differences in evaluation times or 90-day outcome.

Discussion:
In this single center experience, evaluation and treatment times did not differ between men and women except for the time from arrival to neurological exam. While any sex based difference is concerning, further multicenter trials are needed to better understand any possible sex based stroke evaluation and treatment bias.
Abstract W P182: Reducing Door-to-Needle Time by Direct Transfer on CT Table
Authors: Röther Joachim , Bauer de Torres Antonia , Eckert Bernd , Hogan Barbara , Guessow Ulrike , Michahelles Anna , Michels Peter
Published: July 2021

Introduction:
Outcome of acute stroke patients (pts.) treated by thrombolysis is directly related to the door-to-needle time (DNT). We re-organized the management of acute stroke and transfered pts. directly to the CT table in order to reduce DNT. Additionally, the number of stroke mimics was assessed.

Methods:
DNT of 498 consecutive acute stroke pts. in the 6 hour time window were assessed and compared to the DNT before re-organization. Stroke mimics were assessed by extensive diagnostic work-up.

Results:
305/498 (61,4%) pts. submitted by the emergency medical services (EMS) had acute strokes. 59/498 (11,9%) pts. were treated by thrombolysis (19,3% of pts with final diagnosis of stroke) . Mean DNT was 33,7 min. (range 15-70): 22 pts. had a DNT ≤30min, 5 pts. ≤ 20min. and 3 pts. >50min. Direct transfer of pts. to the CT table reduced the DNT from 54min. to 33,7min. 193/498 (38,6 %) pts. submitted with suspected acute stroke were ,,stroke mimics“ . Epileptic seizures and Todd paresis (27%) and electrolyte disorders and infections (16%) were the most frequent final diagnosis.

Discussion:
A minor change in acute stroke management such as direct transfer to the CT table have major effects on DNT. Education of dispatchers and EMS personnel is important to reduce the number of stroke mimics.
Abstract W P19: Propensity Scores Facilitate Unbiased Comparison of Endovascular Devices in IMS III
Authors: Foster Lydia D , Yeatts Sharon D , Tomsick Thomas A , Broderick Joseph P , Palesch Yuko Y
Published: July 2021

Introduction:
The IMS III Trial randomized acute ischemic stroke patients to endovascular (IV tPA + intra-arterial) or IV tPA -only therapy to compare efficacy. However, endovascular subjects were not randomized to a particular approach; interventionalists chose the method. Hence, any statistical comparison of devices must account for potential selection bias.

Methods:
To compare the efficacy and safety of various endovascular treatment modalities, the multiple propensity score (PS) method was implemented to account for potential bias and achieve balance between groups. The analysis is restricted to subjects with an ICA or M1 vessel treated using a standard microcatheter, the Merci retriever, or the Penumbra system. Propensity scores were estimated via a multinomial regression model that included demographic and clinical variables for which 1) an imbalance between devices was demonstrated (α=0.10) or 2) an association with outcome was established (α=0.10). PS tertiles were included as covariates in a logistic regression model relating outcome to device.

Results:
The analysis included 167 subjects treated with a standard microcatheter (n=51), the Merci retriever (n=77) or the Penumbra system (n=39). Unadjusted comparison indicated imbalance between devices in the presence of atrial fibrillation, age, systolic blood pressure, onset to IV tPA start time, and IV tPA start to groin puncture time. Additional covariates included in the PS model varied by outcome. After adjustment for PS tertiles, the initial difference in baseline variables between devices was no longer statistically significant and there was insufficient evidence to conclude that the devices differed for any of the outcomes considered.

Conclusions:
Selection bias was a concern in comparing endovascular approaches in IMS III. The PS method successfully balanced baseline characteristics and facilitated a valid conclusion: major efficacy and safety outcomes did not significantly differ between subjects treated with a standard microcatheter, the Merci retriever, and the Penumbra system. Limitations include small sample size and the possibility of differences in unmeasured baseline characteristics.
Abstract W P197: Pulsed Electromagnetic Field Attenuates High Intracranial Pressure Induced Microvascular Shunting in Rats
Authors: Bragin Denis E , Bragina Olga , Statom Gloria , Nemoto Edwin M
Published: July 2021

Introduction:
We previously reported that high intracranial pressure (ICP) in rats caused a transition from capillary (CAP) to non-nutritive microvascular shunt (MVS) flow associated with tissue hypoxia and increased blood brain barrier (BBB) permeability. We also showed that pulsed electromagnetic field (PEMF) increases blood flow velocity and tissue oxygenation in the normal rat brain. We hypothesized that PEMF attenuates the detrimental effects of non-nutritive MVS flow induced by high ICP.

Methods:
Using in vivo 2-photon laser scanning microscopy (2PLSM) over the rat parietal cortex, we studied the effects of PEMF on microvascular blood flow velocity, tissue oxygenation (NADH) and BBB permeability (dye extravasation) before and during 4 hours of elevated ICP. Doppler cortical flow, rectal and cranial temperatures, intracranial and arterial pressures, blood gases and electrolytes were monitored.

After baseline imaging at normal ICP (10 mmHg), rats were subjected to intracranial hypertension (30 mmHg) by raising an artificial cerebrospinal fluid reservoir connected to a catheter in the cisterna magna. After control recording at high ICP of 30 mmHg, PEMF was applied for 30 min and imaging was continuously performed for up to 4 hours after the treatment. In control animals PEMF was not applied.

Results:
PEMF treatment reduced tissue hypoxia as reflected by a decrease in NADH by 14.6±3.7% (n=7 rats per group, mean ± SEM, p<0.05). BBB permeability was also reduced as reflected by reduction of dye extravasation by 17.2±5.4% (p<0.05). This effect was consistent with dilation of arterioles (+4.5±3.2%) and an increase in capillary blood flow velocity (+4.7±3.2%). PEMF did not completely mitigated the gradual increase in MVS flow at high ICP but, as reflected by MVS/capillary ratio, the transition to non-nutritive flow over 4 hours was less steep in the PEMF treated rats compared to the untreated (2.3±1.1 and 3.8±2.1% change per hour, respectively, p<0.05).

Conclusions:
PEMF reduces tissue hypoxia and BBB degradation by modulating cerebral blood flow topography at intracranial hypertension in a rat brain. PEMF could be an effective treatment for intracranial hypertension after severe cerebral insults.
Abstract W P199: Deficiency of Glia Maturation Factor Abrogates Brain Injury and Inflammation in a Murine Model of Stroke
Authors: Khan Mohammad M , Zaheer Asgar
Published: July 2021

Background and purpose:
Glia maturation factor (GMF), a brain specific protein, discovered and characterized in our laboratory, induces expression of proinflammatory cytokines/ chemokines in the central nervous system (CNS). Recently, it has been demonstrated that deficiency of GMF mitigates neuronal damage in tissue culture cell and animal models of neurodegeneration. Since, GMF expression in brain enhances inflammation; we tested the hypothesis that deficiency of GMF abrogates the inflammatory responses in experimental model of ischemic stroke.

Methods:
Transient focal cerebral ischemia was induced by 1 hour of occlusion of the right middle cerebral artery (MCAO) with a 7.0 monofilament in GMF-containing wild type (Wt) and GMF-deficient (GMF-KO) mice. Mice were anesthetized with 1-1.5% isoflurane mixed with medical oxygen. Body temperature was maintained at 37°C ± 1.0 using a heating pad. At 23 hours after ischemia/reperfusion, mice were tested for neurological scores and were sacrificed for the infarct volume and estimation of inflammatory responses. Immunohistochemistry and western blots were used to analyze the expression and activation of glial cells, and levels of NF-κB in ischemic brain hemisphere.

Results:
We found that levels of GMF significantly increased in MCAO mice compared to saline treated control mice. Next we found that GMF-KO mice exhibited significantly decreased infarct volume, and reduced neurological deficits compared to Wt mice. The decrease in infarct volume and neurological deficits in GMF-KO mice were correlated with a less activation of glia cells, downregulation of NF-κB and suppression of proinflammatory cytokines/chemokine in the ischemic region.

Conclusions:
In conclusion, present study provides the first evidence that deficiency of GMF reduces brain injury and inflammation after ischemic stroke and suggests that the effective suppression of endogenous GMF-function will prove to be an effective and selective strategy to slow deleterious inflammatory processes in ischemic brain injury.

Keywords:
Glia maturation factor; Ischemic stroke; Inflammation; Nuclear factor-κB; Cytokines