bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract WMP19: Prediction of Subacute Infarction in Acute Ischemic Stroke Using Baseline Multi-modal MRI and Deep Learning
Authors: Yu Yannan , Xie Yuan , Thamm Thoralf , Chen Kevin T , Gong Enhao , Zaharchuk Greg
Published: January 2019

Objective:
We aim to investigate if a deep learning algorithm can predict the location and size of subacute infarction in acute stroke patients using input data from baseline multimodal MRI.

Methods:
Acute ischemic stroke patients were reviewed and selected from Imaging Collaterals in Acute Stroke (iCAS) study from Apr 2014 to Aug 2017. We included patients who underwent baseline imaging including perfusion-weighted imaging, diffusion-weighted imaging, gradient echo, and arterial spin labeling; and follow up imaging with FLAIR performed 3-5 days after stroke onset. The ground truth was defined as the stroke lesions on follow-up T2-FLAIR, which were manually delineated by readers blinded to clinical information. Perfusion maps such as Tmax, cerebral blood flow, cerebral blood volume, and mean transient time were reconstructed by RAPID software. All images were co-registered to MNI template space. A U-Net model was trained with the above-mentioned 8 different contrasts as inputs (Figure A). 16 different rigid translation based augmentations were used to augment the training data size. The model was trained based on mixed loss function of cross-entropy and Dice score. Five-fold cross-validation was performed to evaluate the predictions and the results are reported as area under curve (AUC).

Results:
38 patients were included (19 males, age 63±15, mRS 3 [IQR 1-4]). Eight patients underwent IV tPA only, 10 with IV tPA plus thrombectomy, 11 with thrombectomy only, and 9 without reperfusion therapy. The overall AUC of this model reached 0.942±0.053 in all slices, and 0.938±0.050 in slices that contain stroke lesions (Figure B&C), compared to 0.734±0.104 for Tmax map and 0.88±0.12 in a larger previous reported study (Nielsen et al., Stroke 2017).

Conclusions:
Deep learning algorithms can accurately predict established stroke lesions using the information provided in baseline multimodal MRI. This may have value for patient selection for stroke therapies.
Abstract WMP2: The Path from Research to Successful Implementation in Clinical Practice: Endovascular Treatment in the Netherlands
Authors: Wiegers Eveline J , Compagne Kars C , Venema Esmee , Janssen Paula M , Lingsma Hester F , Roozenbeek Bob , Van der Lugt Aad , Dippel Diederik W ,   Mr Clean Registry Investigators
Published: January 2019

Introduction:
In the Netherlands, acute endovascular treatment (EVT) for ischemic stroke was not reimbursed andonly allowed as rescue treatment according to national guidelines until 2016. We describe the trend in use of EVT before, during and after the pivotal thrombectomy trials.

Methods:
Our study used data from all patients who were treated with EVT in the Netherlands from Jan 2002 until Jun 2016 in the Pretrial Registry, MR CLEAN trial and the ongoing MR CLEAN registry. We undertook a time-series analysis to examine trends in the use of EVT using a mixed-effects Poisson regression analysis and several observation plots. Rate ratios (RR) per quarter and 95% confidence intervals (95% CI) were obtained to demonstrate the impact and implementation after the publication of the trial. Regional plots were adjusted for exposure time and population density.

Results:
Between 2004 and 2010, 491 patients were treated with EVT in the Netherlands. In 2010, the MR CLEAN trial started. All hospitals providing EVT in the Netherlands included patients and reimbursement was conditional on participation in MR CLEAN. At first, a non-significant increase in EVT-treated patients was observed (RR: 4.6 [95%CI 0.1-9.1]). In 2015, an immediate steep increase in EVT-treated patients (RR: 20.9 [95%CI 5.5-30.1]) (Fig. 1) and a more even spread over the country was observed (Fig. 2). In the first years after the trial, 33% of the patients who were considered to be eligible for EVT were treated with EVT.

Conclusion:
A strict national policy regarding evidence based treatments can be successful. Ongoing efforts are directed at further increasing the proportion of stroke patients with EVT.
Abstract WMP20: E-Aspects Derived Acute Ischemic Volumes on Non-Contrast Enhanced Computed Tomography Images Correlate With Diffusion Weighted Imaging Lesion Volumes and Predict Clinical Outcome in Acute Ischemic Stroke Patients
Authors: Nagel Simon , Joly Olivier , Pfaff Johannes , Papanagiotou Panagiotes , Fassbender Klaus , Reith Wolfgang , Herweh Christian , Grunwald Iris Q
Published: January 2019

Background and Purpose:
e-ASPECTS derived automated acute ischemic volume (AAIV) measurements on non-contrast computed tomography (NCCT) were correlated with clinical variables and diffusion weighted lesion volumes (DWI) in acute ischemic stroke patients.

Methods:
Data from three studies were reanalyzed with e-ASPECTS Version 7. The National Institute of Health Stroke Scale (NIHSS) determined stroke severity at baseline and clinical outcome was measured with the modified Rankin Scale (mRS) between 45 to 120 days. Spearman ranked correlation coefficients (R) of AAIV and e-ASPECTS scores with DWI lesion volumes, NIHSS and mRS were calculated. Multivariate regression analysis (odds ratio, OR with 95% confidence intervals, CI) and receiver operating characteristic (ROC) curve analysis (area under the curve, AUC with 95% CI) with regard to good outcome (mRS 0-2) were performed.

Results:
In total 388 patients were included. Median AAIV was 33.5+/-24.9 ml, (interquartile range) e-ASPECTS was 9 (8-10) and mean time to scan was 155+/-119 minutes. AAIV and e-ASPECTS correlated strongly (R=-0.78, p<0.001), and AAIV, respectively e-ASPECTS correlated with NIHSS (R=0.33, p<0.001; R=-0.35, p<0.001) and mRS (R=0.31, p<0.001; R=-0.31, p<0.001). AAIV correlated strongly with DWI lesion volume (n=37, R=0.69, p<0.001). AAIV (OR 0.98 per ml, 95% CI 0.97-0.99) was an independent predictor of good outcome, and 29.8 ml (AUC: 0.67, 0.61-0.71) was the optimal cut-off for good outcome.

Conclusion:
AAIV on NCCT is a new feature of the e-ASPECTS software, which significantly correlates with clinical severity and clinical outcome as well as DWI lesion volumes.
Abstract WMP33: Towards Cerebral Aneurysm Rupture Risk Prediction Using Quantitative Analysis by 4D Flow MRI: Intra-Aneurysmal Vortical Blood Flow and Association to Wall Shear Stress
Authors: Elbaz Mohammed S , Aristova Maria , Ma Liliana , Vali Alireza , Bollache Emilie , Barker Alex J , Hurley Michael C , Potts Matthew B , Jahromi Babak S , Ansari Sameer A , Markl Michael , Schnell Susanne
Published: January 2019

Introduction:
While previous studies have shown a link between changes in aneurysmal wall shear stress (WSS) and risk of rupture, the association between the development of WSS variations and intra-aneurysmal hemodynamic flow patterns remain unknown. Understanding such link could potentially lead to novel early biomarkers for risk stratification of aneurysmal rupture.

Aim:
To assess the association between intra-aneurysmal flow patterns behavior and WSS in cerebral aneurysm patients.

Methods:
Time-resolved 3D blood flow velocities were acquired by dual-venc 4D flow MRI (kt-GRAPPA R=5, voxel size (1.0x 1.0 x 1.0 mm
3
), TE/TR 3.5/6.2 ms, temporal resolution 57ms, venc
low
/venc
high
50/100 cm/s) in 12 patients (66 ± 9 years, 8 F), who presented with a total of 14 cerebral aneurysms (average 10-time points per aneurysm synchronized with the cardiac cycle). Time-resolved median WSS was quantified over the 3D aneurysm surface. To quantify 3D blood flow pattern behavior from 4D Flow MRI, we used the fluid dynamics-based helicity metric. Helicity is a signed quantity that measures the strength and alignment between vortical pattern and blood flow directions. Helicity magnitudes take positive values at regions where both vortical pattern and blood flow align in the same direction while regions with opposing directions have negative values. Time-resolved positive and negative helicity were quantified separately by instantaneous volumetric median and correlated with WSS. Correlation was tested using pooled paired data of all acquired time points from all aneurysms (N=147 samples).

Results:
(Fig.1) Strong correlations were found between WSS and flow patterns behavior with the strongest correlation (R=0.91, p<0.001) found with negative helicity.

Conclusions:
We revealed that intra-aneurismal blood flow pattern behavior strongly correlates with wall shear stress. These results may help in the future to identify early hemodynamic markers for risk of aneurysmal rupture.
Abstract WMP38: Early Recurrent Infarction on Serial MRI in Symptomatic Intracranial Atherosclerotic Disease
Authors: Liebeskind David S , Prabkaharan Shyam , Honda Tristan , Campo-Bustillo Iszet , Nizam Azhar , Swanson Seegar , Cotsonis George A , Chimowitz Marc I , Sangha Rajbeer S , Feldmann Edward , Romano Jose G ,   for the MyRIAD Investigators
Published: January 2019

Background:
MyRIAD is a prospective, multicenter, longitudinal observational study to determine the mechanisms of stroke recurrence in intracranial atherosclerotic disease (ICAD). Prior studies suggest that clinical endpoints of recurrent stroke in ICAD exceed 12% at 1 year despite medical management, whereas imaging evidence of early infarction remains largely unknown. We analyzed serial MRI from baseline to 6-8 week MRI in enrolled subjects to ascertain the rate of early infarction in ICAD.

Methods:
All MyRIAD subjects with DWI and FLAIR on qualifying or enrollment MRI followed by 6-8 week MRI were included. Olea Sphere
®
3.0 was used to co-register and align the serial DWI and FLAIR sequences at both timepoints. The presence of new DWI or FLAIR lesions of stroke in the symptomatic territory and DWI or FLAIR lesions outside the territory were determined by lesion mapping.

Results:
Serial MRI data were available in 60/80 (75%) of MyRIAD subjects enrolled to date, in whom target stenosis involved the middle cerebral (n=32), basilar (n=15), internal carotid (n=8) and vertebral (n=5) arteries. Between baseline and follow-up MRI, existing DWI lesions diminished in size (median -0.69 cc, IQR -2.69; n=58) while FLAIR lesions remained the same (median 0 cc, IQR -1.06; n=56). Outside the symptomatic territory, no new lesions were mapped on serial MRI with DWI or FLAIR. In the symptomatic territory, by 6-8 weeks there were discrete new lesions on DWI in 3/58 (5%) and 9/56 (16%) on FLAIR.

Conclusions:
Ischemic infarction in the symptomatic territory of ICAD may be evident on FLAIR and DWI early within the subacute phase. The mechanisms, clinical impact and potential prevention of these new ischemic lesions warrant further investigation.
Abstract WMP4: Fast versus Slow Progressors in Real-World Data From the Trevo Retriever Registry: Collaterals Dominate Time to Reperfusion in Clinical Outcome After Thrombectomy
Authors: Liebeskind David S , Zhang Yanchang , Veznedaroglu Erol , English Joey , Baxter Blaise W , Budzik Ronald F , Bartolini Bruno M , Krajina Antonin , Malek Ali , Sarraj Amrou , Gupta Rishi , Nogueira Raul G ,   for the Trevo Retriever Registry Investigators
Published: January 2019

Background:
Time to reperfusion (TTR) is commonly cited in clinical outcome after endovascular treatment of acute ischemic stroke, yet collaterals may set the pace of ischemia. Real-world data on fast and slow progressors also remain scarce. We analyzed the impact of TTR on clinical outcome in real-world data using core lab adjudicated angiography, interventional steps and corresponding reperfusion.

Methods:
16 key time intervals were calculated from workflow (time of symptom onset, door, picture, puncture) and core lab metrics (clot visualization, first deployment, first reperfusion, final angiography) in real-world data from the Trevo Retriever Registry. These 16 variations of TTR were analyzed overall and by collateral status (ASITN 0-1 versus 2 versus 3-4) to determine the relationship with 90-day clinical outcomes.

Results:
Real-world data on endovascular therapy from 1,441 subjects in the Trevo Retriever Registry were analyzed to relate TTR with clinical outcomes. Overall metrics for TTR are shown in Table 1. TTR was not linked with collateral status. Using a multivariate model incorporating known predictors, there was no influence of TTR using any of the 16 definitions on clinical outcome. Better collateral status on DSA prior to revascularization showed a potent relationship with 90-day mRS (p<0.001) and better probability of functional independence (aOR 1.4, 95% CI 1.2, 1.7) per grade of collateral flow.

Conclusions:
Collaterals transform time to reperfusion, linking fast and slow progressors with subsequent clinical outcomes. TTR may be standardized based on these 16 key epochs in endovascular stroke therapy to document workflow metrics. Time is relative, even when measured with detailed, standardized metrics.
Abstract WMP41: Predictors of Poor Collaterals in Large-Vessel Occlusive Stroke
Authors: Lin Michelle P , Liebeskind David S , Brott Thomas G , Meschia James F , Sam Kevin , Gottesman Rebecca F
Published: January 2019

Introduction:
Robust leptomeningeal collaterals protect brain from ischemia, yet the determinants of poor collaterals remains unclear. We aimed to identify predictors of poor collaterals in patients with large-vessel occlusive stroke.

Methods:
We analyzed 112 consecutive patients with middle cerebral artery ± internal carotid artery occlusion from 2012-2016 who presented within 6 hours after stroke symptoms onset. Collaterals on baseline CT-angiogram (poor collaterals ≤50% filling, good collaterals >50% filling) were reviewed blinded to clinical data. Pre-specified predictors of poor collaterals were analyzed with adjusted logistic regression models: including known predictors (age, vascular risk factors and metabolic derangements) and hypothesized predictors (low cardiac output, elevated inflammatory markers, and imaging evidence for chronic cerebral small-vessel disease and chronic steno-occlusive arterial disease).

Results:
The mean age was 67± 16 years, there were 48% women, 57% white, and median NIHSS was 15 (IQR 11-20). Poor collaterals at baseline were detected in 48%. Multivariable modeling identified that age (aOR 1.8 per 10 years; 95% CI 1.3-2.6; p<0.001), black race (aOR 2.1; 95% CI 1.0-4.5; p=0.043), high blood glucose level (aOR 2.4 per 100 mg/dl; 95% CI 1.1-5.1; p=0.029), and high WMH burden (aOR 6.1; 95%CI 1.8-20.4; p=0.003) were independent predictors of poor collaterals. Associations between low cardiac output, elevated inflammatory markers, intracranial atherosclerosis and poor collaterals did not reach statistical significance (Table).

Conclusions:
We have identified that advanced age, black race, hyperglycemia, and white matter hyperintensities are predictors of poor collaterals. Independent replication study at another institution is ongoing to further explore the hypothesized predictors.
Abstract WMP46: Mitochondrial Ribosomal RNA Expression Correlates With Coated-Platelet Production in Subjects With Asymptomatic Carotid Stenosis
Authors: Kirkpatrick Angelia , Mathews Eleanor , Adrianto Indra , Montgomery Courtney , Dale George
Published: January 2019

Background:
Coated-platelets are procoagulant platelets which are predictive of TIA/stroke among asymptomatic carotid stenosis patients. Previous work in coated-platelets has focused on their characterization and clinical relevance, but the mechanisms that determine individual variability in coated-platelet production remain elusive. We now seek to identify RNA transcripts associated with coated-platelet production.

Methods:
Platelets were obtained from asymptomatic subjects with carotid stenosis. Coated-platelet levels were determined, and platelet RNA was sequenced in subjects with coated-platelet levels <28% and >47%using the Illumina HiSeq 3000. Raw sequence data was aligned to the human genome using TOPHAT, and reads per transcript were counted using HTSeq. Differentially expressed (DE) transcripts with
p
-value < 0.05 and a fold change of >1.25 or < 0.8 were determined using DESeq. Selected DE transcripts were confirmed in 10 additional patient samples using qPCR.

Results:
Twenty samples were sequenced (8 high and 11 low coated-platelet producers, all male), and 144 DE transcripts were identified (118 upregulated, and 26 downregulated in the high coated-platelet producers). Based on previous work identifying mitochondrial depolarization as integral to coated-platelet formation, we assessed for differentially expressed mitochondrial RNAs. Two mitochondrial RNA transcripts demonstrated increased expression in the high coated-platelet samples: RNR1 (2.09-fold, p=0.043) and RNR2 (1.90-fold, p=0.074). Relative RNR1 and RNR2 levels determined by qPCR in 10 additional patient samples correlated with coated-platelet levels (r=0.7017, p=0.024 and r=0.6697, p=0.034 respectively).

Conclusions:
Our results demonstrate a significant correlation between platelet mitochondrial RNR1 and RNR2 transcript levels and coated-platelet production. RNR1 (12S subunit) and RNR2 (16S subunit) are key components of mitochondrial ribosomes. While the functional relationship between increased levels of mitochondrial ribosomal transcripts and increased coated-platelet production is not obvious, it is compatible with the documented involvement of mitochondria in the cascade of events associated with coated-platelet production.
Abstract WMP48: The Impact of Brain Health and Long Range Cortical Disconnection on Stroke Recovery
Authors: Marebwa Barbara K , Wilmskotter Janina , Stark Brielle , Johnson Lisa , Fridriksson Julius , Bonilha Leonardo
Published: January 2019

White matter hyperintensities (WMH) are linked to poor brain health, cardiovascular risk factors, cognitive decline, and stroke. The cumulative effect of microangiopathic changes and perivascular lipohyalinosis is commonly associated with white matter changes in the brain. However, the pathomechanism linking small vessel disease, white matter network disruption, cognitive decline, and stroke recovery is not well understood. We hypothesized that WMH are associated with loss of long range cortical connections, and subsequent disorganization of the optimal topological structure of white matter networks leading to poor post-stroke aphasia recovery. Using post-processing methods of diffusion tensor imaging optimized for lesioned brains, we reconstructed the individual structural whole-brain connectome from 49 right handed participants with a single left hemisphere ischemic stroke (age 59.9±12.5). All participants underwent language assessment using the Western Aphasia Battery (mean 58.9±22.76). WMHs were determined in the right hemisphere aphasia using the Fazekas scale. We assessed the density of each subject’s right hemisphere connectome, and then calculated the Euclidean distance between each pair of node centroids in each connectome. All fibers with lengths above the 3
rd
quartile (75% and above) were designated long range. We further quantified the white matter topological network organization using Newman’s modularity algorithm. We found that participants with high a Fazekas score (especially PWMH) had lower connectome density (r = -0.41, p = 0.003), and more severe aphasia (r = -0.42, p = 0.002). Participants with lower right hemisphere density also had more severe aphasia (r = 0.5, p < 10
-3
). Furthermore, loss of long range cortical connections was associated with the fragmentation of the right hemisphere network topology quantified by the optimal modularity score (r = 0.76, p < 10
-9
). Loss of long range fiber connections related to higher WMH, and was associated with deviations from the optimal topological architecture that signifies a healthy brain. We postulate a mechanism by which brain health is lost – via loss of energy demanding long range fibers resulting in the disorganization of residual brain networks.
Abstract WMP49: Influenza-Like Illness May Trigger Cervical Artery Dissection
Authors: Hunter Madeleine D , Moon Yeseon P , Kulick Erin R , Boehme Amelia K , Elkind Mitchell S
Published: January 2019

Background and Purpose:
Non-traumatic Cervical Artery Dissection (CeAD) is a leading cause of ischemic stroke in patients 15 to 45 years old. Influenza-like illnesses (ILI) have been found to trigger ischemic stroke, but ILI has not been investigated in relation to CeAD. We hypothesized that ILI and influenza would be associated with CeAD.

Methods:
We used a case-crossover design among patients
>
18 years old at time of first non-traumatic CeAD within the New York State (NYS) Department of Health Statewide Planning and Research Cooperative System (2006-2014). We used ICD-9 codes to define CeAD (443.21, 443.24) excluding individuals with major trauma (integer values 800-804 and 850-854), confirmed influenza (480, 487.0, 487.1, 487.8), and a broader influenza definition endorsed by the CDC for ILI surveillance. We compared ILI and influenza in sequential, mutually exclusive intervals preceding CeAD (0-15, 16-30, 31-90, 91-180, and 181-365 days prior to CeAD: case period) and overlapping intervals (0-30, 0-90, 0-180, and 0-365 days prior to CeAD: alternate case period) to ILI and influenza exactly one and two years earlier (control periods). Conditional logistic regression models were used to calculate odds ratios and 95% confidence intervals (OR, 95% CI) before and after adjusting for annual NYS population estimates of influenza prevalence rate.

Results:
Our final sample included 3,861 cases of CeAD (mean age 52±16 and 55.5% of male). We found 1,736 instances of ILI and 113 of influenza during the 3 years preceding CeAD. Patients were more likely to have ILI within 30 days of CeAD compared to the same time one and two years before (0-15 days: adjusted OR 1.53, 95% CI 1.02 - 2.30; 0-30 days: adjusted OR 1.60, 95% CI 1.14 - 2.23). ILI during later overlapping or sequential intervals was not associated with CeAD in adjusted models. Influenza was associated with CeAD between 31 and 90 days after CeAD, but this effect was no longer significant after adjusting for prevalence rate of influenza, perhaps due the small number of patients with confirmed influenza.

Conclusions:
ILI may increase risk of CeAD for up to one month. Further research on mechanisms by which ILI and influenza may trigger dissection are warranted.
Abstract WMP61: Recurrent Stroke Rates in Short versus Long Term Cardiac Monitoring in Patients With Embolic Stroke of Unknown Source
Authors: Ricci Brittany , Chang Andrew , Hemendinger Morgan , Narwal Priya , Dakay Katarina , Cutting Shawna , Mac Grory Brian , Burton Tina , Reznik Michael , Song Christopher , McTaggart Ryan , Jayaraman Mahesh , Panda Nikhil , Chu Antony , Merkler Alexander , Gupta Ajay , Kamel Hooman , Elkind Mitchell S , Furie Karen , Yaghi Shadi
Published: January 2019

Background:
Outpatient cardiac monitoring for 30 days or longer increases detection rates of paroxysmal atrial fibrillation (AF) after cryptogenic stroke, but the ideal duration of monitoring remains unclear. Two commonly used methods of prolonged outpatient cardiac monitoring are 30-day continuous telemetry and insertable cardiac monitors (ICM). We aim to compare rates of AF detection and recurrent stroke between patients with Embolic Stroke of Unknown Source (ESUS) monitored for approximately 30 days (short term) vs. beyond 30 days with ICM (long term).

Methods:
We analyzed a single center retrospective cohort of patients discharged with a diagnosis of ESUS over a two-year period. Patients were divided into two groups based on implemented cardiac monitoring method: short-term (30-day non-invasive monitor) and long-term (ICM

Results:
We identified 117 ESUS patients; 71 patients underwent short-term monitoring and 46 patients underwent long-term monitoring. After a median follow-up of 259 days (IQR 166-468 days), AF was detected in 11.2% (8/71) of patients undergoing short-term cardiac monitoring and 19.6% (9/46) of patients on long-term monitoring; 77.8% of AF was detected beyond 30 days. Recurrent stroke occurred in 12.8% (15/117) of patients. Rates of recurrent stroke were lower in patients undergoing long-term cardiac monitoring vs. only short-term monitoring [adjusted hazard ratio 0.12, 95% confidence interval 0.02-0.89, p = 0.038].

Conclusion:
In a real world ESUS patient cohort, long term monitoring was associated with increased detection of AF and reduced risk of recurrent stroke. Large multicenter prospective studies are needed to confirm our findings.
Abstract WMP62: Duration of Implantable Cardiac Monitoring and Detection of Atrial Fibrillation in Ischemic Stroke Patients: A Systematic Review and Meta-analysis
Authors: Tsivgoulis Georgios , Katsanos Aristeidis H , Köhrmann Martin , Caso Valeria , Perren Fabienne , Palaiodimou Lina , Deftereos Spyridon , Giannopoulos Sotirios , Ellul John , Krogias Christos , Mavridis Dimitris , Triantafyllou Sokratis , Alexandrov Anne W , Schellinger Peter D , Alexandrov Andrei V
Published: January 2019

Introduction:
Although current guidelines indicate that the clinical benefit of prolonged cardiac monitoring for atrial fibrillation (AF) detection in ischemic stroke (IS) patients remains uncertain, clinical trials suggest that implantable cardiac monitors (ICMs) substantially increase AF detection due to prolonged monitoring duration.

Methods:
In the present systematic review and meta-analysis we sought to investigate the association of ICM duration with the yield of AF detection in IS patients. We also assessed whether IS subtype, individual patient characteristics and elapsed time between IS onset and CM implantation may also impact the probability of AF detection. We included studies reporting AF detection rates by ICM in IS patients with negative initial AF screening. We excluded studies reporting prolonged cardiac monitoring with devices other than ICM, not providing AF detection rates or monitoring duration and reporting overlapping data for the same population. Random-effects model was used to calculate the pooled estimates in all subgroup and univariate meta-regression analyses.

Results:
We included 28 studies (4531 patients; mean age:65 years; 52% men). In meta-regression analyses the proportion of AF detection by ICM was independently associated with monitoring duration (coefficient=0.015,95%CI:0.005-0.024) and mean patient age (coefficient=0.009, 95%CI:0.003-0.015). No association was detected with other patient characteristics, including IS subtype (cryptogenic vs. embolic stroke of undetermined source) or time from IS onset to CM implantation. In subgroup analyses significant differences (p<0.001) in the AF detection rates were documented according to ICM duration (<6 months: 4%, 95%CI: 3%-6%; ≥6 months & ≤12 months: 20%, 95%CI: 17%-24%; >12 months & ≤24 months: 26%, 95%CI: 23%-30%; >24 months: 34%, 95%CI: 30%-39%).

Conclusion:
Extended duration of ICM monitoring appears to be the only factor that increases substantially the yield of AF detection in patients with IS and initial negative AF screening. IS subtype and individual patients characteristics, except age, are not related to the probability of AF detection.
Abstract WMP65: Association Between Troponin Levels and Visceral Infarction in Patients With Acute Ischemic Stroke
Authors: Ramasamy Shobana , Patel Praneil , Hung Peter , Finn Caitlin , Gupta Ajay , Okin Peter , Murthy Santosh , Navi Babak B , Kamel Hooman , Merkler Alexander E
Published: January 2019

Introduction:
Elevations in cardiac troponin in the absence of a clinically recognized acute myocardial infarction are typically seen in patients with acute ischemic stroke, though their significance remains unclear. Visceral infarcts appear to be more common in patients with embolic stroke subtypes, but their relation to troponin elevation remains uncertain.

Methods:
Among patients with acute ischemic stroke enrolled in the Cornell AcutE Stroke Academic Registry (CAESAR) from 2011 through 2016, we included those with troponin measured within 24 hours from stroke onset and a contrast-enhanced abdominal computed tomographic scan within 1 year of admission. A troponin elevation was defined as a value exceeding our laboratory’s upper limit of normal (0.04 ng/mL) in the absence of a clinically recognized acute ST-segment elevation myocardial infarction. Visceral infarction was defined as a renal or splenic infarction as ascertained by a single radiologist blinded to patients’ other characteristics including troponin levels. Multiple logistic regression was used to evaluate the association between elevated troponin and visceral infarction after adjustment for demographics and comorbidities.

Results:
Among 2,116 patients registered in CAESAR from 2011-2016, 153 patients had a troponin assay and underwent a contrast-enhanced abdominal computed tomographic scan, of whom 33 (21%) had an elevated troponin and 22 (14%) had a visceral infarct. The prevalence of visceral infarction was higher among patients with an elevated troponin (30%; 95% CI, 16-49%) than among patients without an elevated troponin (10%; 95% CI, 5-17%) (
P
= 0.003). After adjustment for demographics and comorbidities, we found a significant association between elevated troponin and visceral infarct (OR, 3.8; 95% CI, 1.2-11.7).

Conclusions:
Among patients with acute ischemic stroke, elevated troponin in the absence of a clinically recognized acute ST-segment elevation myocardial infarction was associated with visceral infarction, which is typically caused by embolism. Our results support the hypothesis that post-stroke troponin elevation indicates the presence of underlying embolic sources.
Abstract WMP70: Etiology of Stroke Based on Early Analysis of Clot Cytometry Obtained Through First Pass Technique for Mechanical Thrombectomy
Authors: Juega Jesus , Pagola Jorge , Palacio Carlos , Camacho Jessica , Cardona Pere , Quesada Helena , Dorado Laura , Hernandez Maria , De la Torre Carolina , Muchada MArian , Garcia-Tornel Alvaro , Rodriguez-Villatoro Noelia , Boned Sandra , Rodriguez-Luna David , Martinez Elena , Rubiera Marta , Ramon y Cajal Agueras Santiago , Ribo Marc , Tomasello Alejandro , Molina Carlos
Published: January 2019

Introduction:
Mechanical thrombectomy is the best treatment for large vessel occlusion in acute strokes, this technique can obtain clots for further analysis.

Objective:
To evaluate flow cytometry in thrombi obtained in the treatment of hyperacute stroke by mechanical thrombectomy, as a diagnostic tool in the etiological study of stroke

Methods:
Consecutively, intracranial clots were obtained in the hyperacute phase of stroke with solitaire device. Cell suspensions of thrombi were prepared that were labeled by direct immunofluorescence using conjugated monoclonal antibodies. The labeled samples were acquired in a Naviostm flow cytometer (Beckman-Coulter). The following leukocyte populations were studied: granulocytes, monocytes, total lymphocytes, T lymphocytes (CD3 +), helper T lymphocytes (CD3 +, CD4 +), suppressor-cytotoxic T lymphocytes (CD3 +, CD8 +), TNK lymphocytes (CD3 +, CD56 / 16 +) , NK lymphocytes (CD3-, CD56 / 16 +) and B lymphocytes (CD19 +). The results were expressed as percentages (%). The aetiology of stroke was categorized in secondary to: major structural heart disease, atrial fibrillation, stroke of atherosclerotic etiology (severe stenosis or complicated aortic atheromatosis ulceration) or infrequent causes.

Results:
40 samples were analyzed. Clots of atherosclerotic etiology (n = 13) were associated with higher% of CD4 T lymphocytes (24.85% vs 15.83% p = 0.016), and higher% of NK (21.08% vs 17.04) % p = 0.07), also showed a tendency to a higher% LT (23.69% vs 16.46% p = 0.052). Strokes secondary to AF were associated with a higher percentage of CD8 T lymphocytes (20.24 vs 13.56 p = 0.048).

Conclussion:
Analysis by flow cytometry of clots obtained in the hyperacute phase of stroke showed significant differences in the different lymphocyte populations according to the etiology
Abstract WMP71: Atrial Fibrillation and Atrial Flutter After Ischemic Stroke in Black versus White Medicare Beneficiaries
Authors: Kamel Hooman , Kleindorfer Dawn O , Levitan Emily , Bhave Prashant D , Soliman Elsayed Z
Published: January 2019

Introduction:
Several studies suggest that black U.S. residents have a lower risk of atrial fibrillation (AF) and a similar risk of atrial flutter (AFL) compared to whites. It remains unclear whether these differences reflect screening practices or true differences in risk. Because individuals with ischemic stroke are usually screened for AF as part of standard care, this population may provide insights into racial differences in the risk of AF and AFL.

Methods:
We performed a retrospective cohort study using inpatient and outpatient claims between 2008-2015 from a nationally representative 5% sample of Medicare beneficiaries. We included patients of black or white race who were ≥65 years old and hospitalized with ischemic stroke, defined by validated
ICD-9-CM
diagnosis codes. Validated codes were used to identify the outcomes of AF and AFL. We excluded patients with AF or AFL before discharge from their first documented stroke hospitalization. We adjusted for post-stroke heart-rhythm monitoring, classified as Holter monitors, external loop recorders, implanted loop recorders, or interrogations of implanted pacemakers/defibrillators. We calculated AF and AFL incidence rates and hazard ratios (HR) using Cox proportional hazards models.

Results:
Among 36,624 patients with ischemic stroke and no prior AF/AFL, the 5,095 black patients were slightly younger (mean age, 76.7 versus 78.9 years) but had more hypertension, diabetes, heart failure, and chronic kidney disease. During a mean follow-up of 2.0 years, the incidence of AF was 4.5 per 100 person-years and that of AFL was 0.5 per 100 person-years. Black race was associated with a lower risk of post-stroke AF (HR, 0.86; 95% CI, 0.77-0.96) including after adjustment for demographics, vascular risk factors, and post-stroke heart-rhythm monitoring (HR, 0.88; 95% CI, 0.79-0.98). There was no association between black race and post-stroke AFL in the unadjusted model (HR, 1.04; 95% CI, 0.78-1.39) or adjusted model (HR, 1.06; 95% CI, 0.79-1.44).

Conclusions:
We found that black patients with ischemic stroke had a lower rate of post-stroke AF and a similar rate of post-stroke AFL compared to whites.
Abstract WMP75: A Modified, Recombinant Tissue Plasminogen Activator-Responding Photothrombotic Stroke Model
Authors: Sun Yu-Yo , Kuan Chia-Yi
Published: January 2019

Introduction:
Photodynamical dye-based stroke models (e.g. Rose Bengal RB/photothrombosis) have several attractive features, including simple surgical procedures, consistent infarct size, and low mortality rate. Yet, because RB/photothrombosis mainly induces platelet-rich but fibrin-poor clots, it responds to recombinant tissue plasminogen activator (rtPA)-based lytic therapy poorly making it less suitable for studying reperfusion injury or improving lytic therapy.

Hypothesis:
We hypothesize the addition of thrombin to Rose Bengal dye in photothrombosis will increase the fibrin component in clots, making it more susceptible to rtPA-thrombolysis.

Methods:
Based on the standard RB/photothrombotic stroke procedures (intravenous injection of 50 mg/kg RB, we mixed a subthreshold level of bovine thrombin with RB to create a thrombin-Rose Bengal (TRB)/photothrombotic stroke model. We compared the clot composition, effects of rtPA treatment on cerebral blood flow reperfusion, and the infarct size following rtTA treatment initiated at 30, 60, or 120 min after photothrombosis.

Results:
We report four sets of results. First, the addition of thrombin did not increase mortality rate or infarct size, when compared to standard RB/photothrombosis. Second, immunostaining showed a scant amount of fibrin at the border of RB/photothrombosis-induced clots. In contrast, fibrin was mixed with erythrocytes throughout TRB/photothrombosis-induced clots. Third, laser speckle contrast imaging indicated that intravenous infusion of rtPA (10 mg/kg) at 30 min after TRB/photothrombosis improved blood flow in the MCA-supplied area, but the same treatment had little effect in RB/photothrombosis. Finally, the therapeutic window of rtPA-treatment is at least 2 h in TRB/photothrombosis (n>10 in each group).

Conclusions:
Our results confirm the notion by Dr. Brant Watson et al. that rtPA lytic treatment confers little benefits in RB/photothrombosis, likely due to its fibrin-poor clots. Yet, the addition of subthreshold thrombin (TRB/photothrombosis) elevates the fibrin component in clot, making it far more responsive to rtPA-thrombolysis. The modified, rtPA-responding thrombotic stroke model may have broad applications in experimental stroke research.
Abstract WMP93: Addressing Stroke Patient and Family Reasons for Not Calling 911
Authors: Ramirez Maygret , Bedgio Rodney , Ramos Virginia , Gonzalez Ivis C , Miro Gonzalez Yaima , Starosciak Amy K , D'Amour Daniel , Strauss Jayme , De Los Rios La Rosa Felipe
Published: January 2019

Objective:
Our Comprehensive Stroke Center regularly provides community outreach and stroke education. The stroke team educates on signs and symptoms of stroke, risks factors, and 911 activation. Emergency response units then activate our stroke response teams for prompt treatment in keeping with our motto “time is brain.” Approximately 1/3 of our stroke alerts are walk-ins, and at our sister hospitals (primary and acute stroke ready), nearly 2/3 of their stroke alerts are walk-ins. The purpose of this survey is to determine common reasons why 911 was not called for possible strokes to improve community stroke education interventions.

Method:
Neuroscience nurses call all stroke patients within a few days of discharge to ensure patients have obtained their prescription medications, have follow-up appointments, inquire about their satisfaction with our services, and reinforce stroke education. In June 2018, as part of these calls, our team asked why patients/families did not call 911, then provided education on the importance of calling EMS. Between 6/6/2018 and 8/6/2018, 171 stroke patients were called and we reached 135 (79%). Of those, 131 cases had transportation information and 43 (33%) patients arrived as a walk-in.

Results:
Five patients were unsure or could not provide a response as to why 911 was not called. Out of the 38 cases for which an answer was given, 12 patients (32%) reported hospital preference, and did not call because they were sure that EMS would take them to a different, closer hospital. Other responses were that the patient or family did not realize it was an emergency (18%), a family member preferred to drive (13%), the patient or family thought it would be faster to drive (11%), the incident occurred close to the hospital or in a car (11%), the cost was prohibitive (3%), or other (13%).

Conclusion:
The most common reason patients and families gave for not calling 911 was their hospital preference. Fire Officers Association of Miami-Dade (FOAMD) uses an algorithm based on a pre-hospital stroke scale, time since last known well, and distance from scene to stroke center to triage patients. Targeted community educational efforts on this algorithm may lead to higher rates of 911 use for suspected stroke.
Abstract WMP95: The Effect of Race and White Matter Hyperintensity on Quality of Life Following Lacunar Stroke: A Secondary Analysis of SPS3 Study
Authors: Meyer Chelsea , Ruff Jerdan , de Havenon Adam
Published: January 2019

Introduction:
Quality of life after stroke is affected by multiple social and biological factors. The interaction between white matter hyperintensity (WMH) burden and race have not previously been evaluated as predictors of quality of life post-stroke.

Hypothesis:
Larger WMH burden, measured by the Fazekas score on MRI, will negatively impact quality of life post lacunar stroke and will have more of an impact on non-white patients.

Methods:
We included SPS3 patients with Fazekas score at study enrollment and race dichotomized into white vs. non-white. The primary outcome was quality of life score on stroke specific quality of life scale (ss-QoL) at baseline and at study completion (mean follow-up 3.4 years). We used ANOVA to test for difference in the mean ss-QoL between Fazekas score.

Results:
There were 2804 participants with baseline ss-QoL and 2185 participants with ss-QoL at study completion. Mean age was 62.7 ± 10.7 years, 62% were male and 53.6% white. Non-white participants had a lower mean ss-QoL post-stroke compared to white participants (Table 1), but all had improvement in ss-QoL scores at study completion when compared to baseline. Fazekas score had a negative impact in ss-QoL for white participants but not in non-whites at study baseline, and both groups had a significant impact of Fazekas on ss-QoL at study completion (Table 1). This significance persisted in a multivariate model adjusted for confounders that may have impacted ss-QoL (Table 2).

Conclusion:
Larger WMH burden negatively impacts quality of life after lacunar stroke. The overall quality of life is also lower in non-whites-compared to whites, and there is less of an impact of WMH burden on quality of life for non-whites.
Abstract WP100: Temporal Trend in the Rates of sICH and Serious Hemorrhage After IV Thrombolysis Among Patients on Dual Antiplatelet Therapy
Authors: Ali Syed F , Schwamm Lee , Hemmen Thomas , Anderson Christopher , Onteddu Sanjeeva , Nalleballe Krishna
Published: January 2019

Introduction:
Previous studies have shown conflicting results regarding the risk of symptomatic intracerebral hemorrhage (sICH) following thrombolysis for acute ischemic stroke in the setting of dual antiplatelet therapy (DAPT) use prior to the index stroke. We explored the temporal trend in the rates of sICH and the safety of IV tPA among patients treated with thrombolytics while on DAPT.

Methods:
Using local GWTG stroke registry data from three large comprehensive stroke centers in Northeast, South and West, we included 2,851 confirmed stroke patients who received tPA from 01/2008 - 06/2018 and plotted the temporal trend of sICH frequency over time, using the GWTG definition of ICH documented by imaging within 36 hours of thrombolysis and with clinical deterioration attributable to hemorrhage. We compared rates of sICH and serious systemic hemorrhage (>3 transfused units of blood within 7 days) between 3 groups of patients stratified by prior antiplatelet use: Group 1- no antiplatelet use, Group 2- monotherapy, Group 3 - DAPT.

Results:
Of the total 2,851 patients treated with IV tPA, 132 (4.6%) had sICH and 27 (0.9%) had serious systemic hemorrhage. Temporal trends showed a decrease in the overall rates of sICH from 2008 to 2017. The proportion of cases differed by group with 68.7% in Group 1, 31.3% in Group 2 and 4.0% in Group 3. Within Group 2, aspirin was the most common drug (28.1% Aspirin, 2.5% Clopidogrel, 0.7% others). Rates of sICH did not differ by Group (4.5%, 4.8% and 3.5% in Group 1, 2 and 3 respectively (NS).

Conclusion:
Rates of sICH after IV tPA decreased overtime in our centers, perhaps due to tPA use in milder stroke patients, and better patient selection and post-tPA management. The rate of sICH was similar in patients with no, single or dual antiplatelet therapy before the stroke, suggesting that the concurrent use of DAPT is not a concern prior to thrombolysis. Further studies are needed to confirm our findings.
Abstract WP109: Early Neurological Decline in Acute Ischemic Stroke Patients Receiving Thrombolysis With Large Vessel Occlusion and Initial Mild Deficits
Authors: Lee Vivien H , Powers Ciarán J , Nimjee Shahid M , Youssef Patrick , Torbey Michel
Published: January 2019

Introduction:
One quarter of ischemic stroke patients with initial mild deficits will have poor outcome. We sought to determine the rate of early neurological decline in acute ischemic stroke patients with large vessel occlusion (LVO) presenting with mild deficits.

Methods:
Among 322 acute ischemic stroke patients who received intravenous tissue plasminogen activator (IVtPA) from July 1, 2016 to July 1, 2017, we identified 76 (23.6%) with imaging confirmed anterior circulation LVO, defined as M1, M2, or carotid terminus (ICAT). Basilar artery occlusions were excluded. Mild deficits were defined as National Institutes of Health Stroke Scale (NIHSS)
<
7. Data was abstracted on demographics, neuroimaging, need for intra-arterial therapy (IAT) revascularization, final Thrombolysis in Cerebral Infarction score (TICI), and clinical presentation. Early neurological decline was defined as NIHSS worsening of
>
4 points within 24 hours.

Results:
Among 76 patients with LVO, we identified 22 (29%) who presented with initial low NIHSS (< 7). The mean age was 64.7 years (range 26 to 93). IVtPA time from last known well (LKN) was a mean 2.7 hours (range 1.3 to 4.9). Most patients (91%) were transfers from outside facilities. LVO sites were as follows: 4 (18%) ICAT, 7 (32%) M1, and 11 (50%) M2. Most (19/22 86%) had CT perfusion imaging, and large mismatch was seen in 6/8 with worsening and 6/11 without worsening. Among the 22 patients with mild deficits initially, 9 (41%) had early neurological decline. Patients with early neurological decline were significantly older (77.8 vs 55.7 years, p=0.0008). Among 9 patients with decline, the mean change in NIHSS was 9 points (range, 4 to 18) and 3 (13.6%) underwent rescue therapy with IAT with TICI 2b (1) and TICI 3 (2) revascularization. On hospital discharge, LVO patients with neurological decline were significantly less likely to be discharged home compared with patients without decline (22% vs 69%, p=0.03).

Conclusions:
Among LVO patients who received IVtPA, 29% presented with mild deficits (NIHSS <7). Among these patients with mild deficits, early neurological decline occurred in 41% despite receiving IVtPA and was associated with older age. CTP mismatch did not accurately predict which patients would worsen.