bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract WP216: Predicting Sleep Apnea After Ischemic Stroke
Authors: Brown Devin L , He Kevin , Kim Sehee , Hsu Chia-Wei , Case Erin , Chervin Ronald , Lisabeth Lynda
Published: June 2021

Introduction:
Sleep apnea (SA) is highly prevalent after stroke and is associated with poor stroke outcomes. Currently, after stroke, a physiological test must be used to differentiate patients with and without SA. Within a large, population-based study, we tested the usefulness of statistical models based on baseline characteristics to predict SA.

Methods:
Within the Brain Attack Surveillance in Corpus Christi (BASIC) project, participants with ischemic stroke (2010-2018) underwent SA screening, shortly after stroke, with the ApneaLink Plus portable sleep apnea testing device. The respiratory event index (REI) was calculated as the number of apneas and hypopneas per hour of recording; values ≥10 defined SA. Logistic regression and the Distributed Random Forest Classifier (a machine learning technique) were applied to predict SA with the following as predictors: demographics, stroke risk factors, stroke severity (NIHSS), neck and waist circumference, palate position, and pre-stroke symptoms of snoring, apneas, and sleepiness. Models were internally validated with cross-validation.

Results:
Within the total sample (n=1,330), median age was 65; 47% were women; 32% non-Hispanic white, 62% Mexican American, and 6% African American. SA was found in 67%. The area under the receiver operating characteristic curve, a measure of predictive ability, applied to the validation sample, was 0.69 for logistic regression and 0.74 for the random forest model. Random forest correctly classified 72.3% of validation samples, while logistic regression correctly classified 70.7% of validation samples. The most important features for predicting SA were waist circumference, neck circumference, body mass index, NIHSS, and pre-stroke daytime sleepiness.

Conclusions:
In this large, ethnically diverse, population-based sample of ischemic stroke patients, prediction models based on easily obtained baseline characteristics and simple measurements resulted in fair performance, despite use of advanced statistical and machine learning techniques. Physiological tests are still needed to differentiate ischemic stroke patients with and without SA.
Abstract WP22: Reperfusion Therapy After Neurological Deterioration in Acute Ischemic Stroke
Authors: Park Mooseok , Park Tai Hwan , Park Sang-Soon , Park Jong-Moo , Cho Yong-Jin , Lee Kyung Bok , Lee Soo Joo , Kim Beom Joon , Cha Jae-Kwan , Lee Jun , Kim Dong-Eog , Kim Joon-Tae , Choi Jay Chol , Lee Byung-Chul , Kim Wook-Joo , Shin Dong-Ick , Sohn Sung Il , Lee Ji Sung , Lee Juneyoung , Lee Jung-Gon , Bae Hee-Joon
Published: June 2021

Background:
Guidelines do not recommend reperfusion therapy in acute ischemic stroke patients with mild symptoms considering low gain compared to the risk. However, some patients with mild first symptoms experience neurological deterioration (ND) after hospitalization. We aimed to analyze clinical features and outcomes of patient who received reperfusion therapy after ND occurred.

Methods:
We enrolled patients who were admitted within 7 days after acute ischemic stroke or TIA between January 2012 and July 2018 from a multicenter stroke registry database in Korea (CRCS-K). Patients who 1) admitted via emergency room, and 2) received reperfusion therapy including intravenous tissue plasminogen activator and/or endovascular treatment were included. Clinical features and outcomes such as modified Rankin Scale (mRS) score distribution at 3 months after stroke were compared between patients received reperfusion therapy after ND and those without ND before the treatment.

Results:
Among 51325 patients, 6577 (12.8%) received reperfusion therapy were identified. Reperfusion therapy was performed after ND in 136 patients (2.1%). Mean time of onset to needle is 342.1 and 167.2, and onset to perfusion is 1351.6 and 422.0 in patients treated after ND, and those without, respectively. TIA history was more frequent and atrial fibrillation history was less frequent in patients treated after ND. Initial median (IQR) National Institute of Health Stroke Scale (NIHSS) score was 8 (5 - 12), 10 (6 - 16) in patients treated after ND, and those without, respectively. Large artery atherosclerosis was more frequent in patients treated after ND (42.9 % vs. 26.7%). There was higher rate of good outcome at 90 days in patients treated after ND (84 [61.8%]) compared with those without ND before treatment (3359 [52.2%]; OR, 1.38 [95% CI, 1.02-1.87]). In multivariable analysis, good outcome at 90 days in patients treated after ND lacked statistical significance (OR, 1.06 [95% CI, 0.71-1.62]). There is no significant statistical difference of death at 90 days (13.2% vs. 10.4%,
p
= 0.364).

Conclusion:
Reperfusion therapy could apply patients with mild first symptoms experience ND after hospitalization and expect similar prognosis compared to those without ND before the treatment.
Abstract WP227: Risk Factors for Pathophysiologic Subtypes of Ischemic Stroke Among West Africans: Findings From the SIREN Study
Authors: Sarfo Fred S , Ovbiagele Bruce , Akpa Onoja M , Akinyemi Rufus , Akpalu Albert , Wahab Kolawole , Obiako Reginald , Owolabi Lukman , Gebregziabher Mulugeta , Owolabi Mayowa
Published: June 2021

Background:
The risk factors associated with the occurrence of the distinct pathophysiologic subtypes of ischemic stroke are unknown among indigenous Africans.

Objective:
To identify and quantify the contributions of risk factors for occurrence of ischemic stroke and its etiologic subtypes among West Africans.

Methods:
The Stroke Investigative Research and Educational Network (SIREN) is a multicenter, case-control study involving 15 sites in Nigeria and Ghana. Cases included adults aged >18 years with CT/MRI confirmed stroke and ischemic strokes were etiologically subtyped using the TOAST protocol. Controls were age-and-gender matched stroke-free adults recruited from the communities in catchment areas of cases. Comprehensive evaluation for vascular, lifestyle and psychosocial factors was performed using standard instruments. We used conditional logistic regression to estimate odds ratios (OR) with 95% CIs.

Results:
There were 1,721 ischemic stroke cases with a mean age of 62.19 ± 14.03 vs 60.86 ± 13.71 for controls. Using the TOAST etiologic scheme, 867 (50.3%) were small vessel occlusions, 425(24.7%) were large-artery atherosclerotic, 181(10.5%) were cardio-embolic, 204(11.9%) were undetermined and 44(2.6%) were of other determined etiology. The 7 dominant risk factors for ischemic strokes aOR (95%CI) were hypertension 10.76(7.15-16.20), dyslipidemia 5.30(3.86-7.29), diabetes 3.61(2.72-4.80), psychosocial stress 1.68(1.20-2.35), cardiac disease 1.94 (1.25-3.02), meat consumption 2.02(1.54-2.65), green vegetable consumption 0.44(0.33-0.59). Hypertension, dyslipidemia, diabetes, meat consumption and green vegetable intake were confluent factors shared by small-vessel, large-vessel and cardio-embolic ischemic stroke subtypes.

Conclusion:
We provide empiric evidence of risk factors to be targeted for stroke prevention. Our findings open a vista into future studies aimed at elucidating the genetic factors linked with pathophysiologic subtypes of stroke among Africans.
Abstract WP23: Is There Increased Incidence of Subarachnoid Hemorrhage With Use of Stentrievers in Distal Circulation?
Authors: Kulhari Ashish , Ro Daniel , Singh Amrinder , Fourcand Farah , Dhanesar Gurneel Kaur , Vyas Zinal , Zacharatos Haralabos , Mehta Siddhart , Kirmani Jawad F.
Published: June 2021

Background:
Multiple recent positive endovascular trials have proven mechanical thrombectomy as standard of care for large vessel occlusion (LVO) of the Anterior Circulation (AC). Post-thrombectomy subarachnoid hemorrhage (PT-SAH) is a known complication of this procedure. The aim of this study was to compare the incidence of SAH in proximal (ICA terminus and MCA M1) versus distal (MCA M2 and beyond) LVOs with use of stentrievers.

Methods:
Retrospective analysis of patients who underwent anterior circulation acute ischemic stroke interventions (AISI) at a community based, university affiliated comprehensive stroke center during a 5 year period (2014-2019) was done. AISI using stentrievers were separated in 2 groups based on location of LVO (Proximal and Distal). Post procedure CT heads were reviewed for SAH in location of stent deployment.

Results:
2980 patients presented with acute ischemic stroke during the pre-specified time period. Of those, 2,682 were anterior circulation strokes. Of those, 373 received AISI. Stentrievers were used in 193 patients. Proximal occlusions (ICA terminus and MCA M1) were placed into Group A (n=150). Distal occlusions (MCA M2 and beyond) were placed into Group B (n=43). Group A had 6% SAH (n=9); Group B had 16% SAH (n=7) (p value <0.05).

Conclusion:
This study reveals an increased incidence of PT-SAH for distal LVOs. Main limitation of the study is the small sample size. Next generation stentrievers with smaller stent size and different design may decrease incidence of PT-SAH. Larger prospective RCTs are warranted to validate these results.
Abstract WP234: Association of Social Trust With Subsequent Stroke and Cardiovascular Disease Risk
Authors: Hwang Seo Eun , Choi Seulggie , Oh Juhwan , Lee Jong-Koo , Park Sang Min
Published: June 2021

Introduction:
Although social capital has been shown to be one of the important social determinants of health, the association between social trust and the risk of stroke and cardiovascular disease (CVD) is not clear yet. We aimed to investigate the association of social trust with stroke and CVD risk using a large Asian population.

Methods:
The study data was derived from the Korean National Health Insurance Service database. Community-level social trust was determined from the Koran Community Health Survey. The study population consisted of 2,156,829 participations. According to social trust index measured in the area of residence during 2011, participants were followed-up from 1 January 2012 to 31 December 2016. Multivariate Cox proportional hazards regression was used to determine the adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) for stroke and CVD risk according to quintiles of social trust.

Results:
Compared to those with the lowest quintile of social trust, participants within the highest quintile had lower risk for stroke (aHR 0.90, 95% CI 0.87-0.93) and CVD (aHR 0.91, 95% CI 0.89-0.93), and the risk-reducing association of high social trust on CVD risk was preserved after additional adjustments for lifestyle behaviors including smoking, alcohol intake, and physical activity.

Conclusion:
Higher social trust was associated with reduced risk of stroke and CVD even after considering lifestyle behaviors. Social trust in a community level is an important determinant of stroke risk and enhancing social trust may lead to reduced risk of stroke and CVD.
Abstract WP235: Risk of Arterial Ischemic Events After Non-Traumatic Subdural Hemorrhage
Authors: Murthy Santosh B , Wu Xian , Diaz Ivan , Parasram Melvin , Parikh Neal S , Merkler Alexander , Falcone Guido , Navi Babak B , Sheth Kevin N , Kamel Hooman
Published: June 2021

Introduction:
To study the risk of arterial ischemic events after non-traumatic subdural hemorrhage (SDH).

Methods:
We performed a retrospective cohort study using inpatient and outpatient claims data from 2008-2015 from a nationally representative 5% sample of Medicare beneficiaries. The exposure was diagnosis of SDH. Our primary outcome was an arterial ischemic event defined as a composite of acute ischemic stroke and acute myocardial infarction (MI). Secondary outcomes were ischemic stroke alone and MI alone. We used validated
ICD-9-CM
diagnosis codes to identify our predictor and outcomes. We excluded patients who had an arterial ischemic event prior to SDH diagnosis. Using Cox regression and corresponding survival probabilities, adjusted for demographics and vascular comorbidities, we computed the hazard ratio (HR) in each 4-week interval after discharge for SDH. We performed secondary analyses stratified by strong indications for antithrombotic therapy (composite of atrial fibrillation, peripheral vascular disease, valvular heart disease and venous thromboembolism).

Results:
Among 1.7 million Medicare beneficiaries, 2,939 were diagnosed with SDH. Compared to patients without SDH, those with SDH were more often older, male, and had more vascular risk factors. In the 4 weeks after SDH, patients’ risk of an arterial ischemic event was substantially increased (HR, 4.2; 95% CI, 2.2-6.7). There was no association between SDH diagnosis and arterial ischemic event risk beyond 4 weeks. In secondary analysis, during the 4 weeks after SDH, patients’ risk of ischemic stroke was increased (HR, 5.6; 95% CI, 3.6-9.7) but not their risk of MI (HR, 0.8, 95% CI, 0.2-1.7). Patients with strong indications for antithrombotic therapy had similarly increased risks for arterial ischemic events as compared to patients in the primary analysis; patients without strong indications for antithrombotic did not demonstrate an increased risk for arterial ischemic events.

Conclusions:
Among Medicare beneficiaries, we found a heightened risk of arterial ischemic events, particularly ischemic stroke, in the four weeks after SDH. This increased risk may be driven by withholding of antithrombotic therapy after SDH diagnosis.
Abstract WP239: Ethnic Differences in Multiple Chronic Conditions Among Ischemic Stroke Patients From the Brain Attack Surveillance in Corpus Christi Project
Authors: Jiang Xiaqing , Wang Lu , Cigolle Christine , Lisabeth Lynda
Published: June 2021

Introduction:
The risk of developing multiple chronic conditions (MCC) increases with age. MCC predicts stroke outcomes and impairs prestroke reserve that aids the neuropsychological process of stroke recovery. Mexican Americans (MAs) have increased stroke risk, worse stroke outcomes and a different profile of pre-stroke comorbidities compared to non-Hispanic whites (NHWs). We assessed ethnic differences in the overall burden of MCC among ischemic stroke patients from a bi-ethnic, population-based stroke study.

Methods:
We studied patients with ischemic stroke between November 2008 and March 2017. Twenty-two chronic conditions (prevalence 1%-83%) were identified from medical records and ICD-9 and 10 codes from hospital discharge data. MCC burden was measured by the total number of chronic conditions. Ethnic differences in terms of the odds of experiencing none (<2 conditions), low MCC (2-3 conditions), or high MCC (>4 conditions) were assessed using a proportional odds model adjusting for age (at stroke onset). Effect modification by age was also investigated.

Results:
Of 1,656 stroke patients, 68% were MA, 51% were female, mean age was 69 (SD=13), median number of MCC was 4 (IQR: 2-6). MAs were younger at stroke onset, but more likely to have higher age-adjusted MCC burden (OR 1.32, 95% CI: 1.07-1.62) compared to NHWs. The difference in MCC burden was modified by age (p= 0.02), with greater ethnic difference in MCC burden among younger patients (Figure).

Conclusion:
MAs have greater MCC burden at stroke onset compared to NHWs, especially in younger patients. The contribution of this ethnic difference in MCC burden to ethnic disparities in stroke outcome needs further investigation.
Abstract WP243: Assessment of Racial and Gender Disparities in Transfer Times During Inter Facility Transfer for Thrombectomy Evaluation
Authors: Reddy Sujan Teegala , Wu Tzu-Ching , Zhang Xu , Vahidy Farhaan , Ankrom Christy , Rosenbaum-Halevi David , Savitz Sean
Published: June 2021

Introduction:
It is known that racial and gender differences exist in incidence of acute ischemic stroke (AIS) presentations. We evaluated racial and gender differences in tele-stroke evaluation and transfer times in AIS patients during inter-facility transfer for potential EVT.

Methods:
We retrospectively analyzed AIS patients transferred from 13 referring hospitals (RH) to our hub at the University of Texas Health Science Center at Houston, covering the greater Houston area, from September 2015 to April 2018. Tele-stroke consultation (TSC) times were defined as time from RH arrival to tele-stroke consult page. Notification within 15 minutes of arrival, as indicated in the AHA target stroke guidelines, was used as a cut-off to identify delayed consult times. Transfer times (TT) were defined as time between CT brain acquisitions at RH to arrival time at hub.

Results:
A total of 306 patients were analyzed which included Caucasians (55%), African Americans (26%), Hispanics (15%), Asian Americans (3%) and those not reported (1%). Median (IQR) age was higher in Caucasians [69 (59, 80) years] compared to Hispanics [65 (57, 79) years] and African Americans [58 (49, 73) years], (p value = 0.26 and <0.001, respectively), and in females [69 (57, 81) years] compared to males [63 (54, 74) years], (p value <0.001). Females had higher NIHSS on presentation compared to males [16 (11, 22) vs. 14 (9, 20), p value = 0.024]. Median TSC was 15 minutes (IQR, 8, 25). Time to consultation >15 minutes was noted in 148 (48.4%) patients in the overall cohort. Median TT was 2.68 hours (IQR, 2.17, 3.32). There were no significant differences in tele-stroke consult times and transfer times when compared by gender and race (Table 1).

Conclusions:
No racial and gender disparities were found in tele-stroke consult request times and transfer times during inter-facility transfer for potential EVT evaluation. Further investigation is needed to understand reasons for prolonged time to consultation>15 minutes.
Abstract WP249: Association of Reduced FEV1 and Stroke Risk
Authors: Lyden Stephanie , De Havenon Adam , Reddy Vivek
Published: June 2021

Background:
The systemic inflammation and oxidative stress of obstructive lung disease could promote cerebrovascular dysfunction and platelet hyperactivity, thereby increasing stroke risk
1-2
. There have been studies in the literature supporting an increased risk for stroke (ischemic and hemorrhagic) in patients with obstructive lung disease
3-4
. We aim to assess whether this association is confirmed using data collected from the Cardiovascular Health Study (CHS).

Methods:
This is a secondary analysis of CHS. The primary outcome is ischemic stroke and the secondary outcome is hemorrhagic stroke. The primary predictor is abnormal pulmonary function at the baseline visit, defined as FEV1<80% of predicted. We fit Cox proportional hazards models and adjusted for baseline covariates that were associated with the outcomes, which for ischemic stroke included age, race, smoking, cholesterol, diabetes, hypertension, atrial fibrillation, and history of TIA or myocardial infarction; and for hemorrhagic stroke included age, cholesterol, diabetes, and hypertension.

Results:
We included 5,438 patients, of whom 880 (16.2%) had ischemic stroke and 142 (2.6%) had hemorrhagic stroke. Mean (SD) days of follow-up was 4,458 (2,499). There were 331/5,438 (6.1%) of patients with abnormal pulmonary function at baseline, who had a higher risk of ischemic stroke (HR 1.36, 95% CI 1.05-1.76, p=0.019) (Figure 1). This remained significant in the adjusted multivariate model (HR 1.43, 95% CI 1.08-1.90, p=0.013). Abnormal pulmonary function was not associated with hemorrhagic stroke risk in either the unadjusted (p=0.635) or adjusted models (p=0.659).

Conclusion:
Patient’s with a reduced FEV1<80% were found to have an increased risk for ischemic stroke. However, this was not associated with an increased risk for hemorrhagic stroke, suggesting a less robust link between obstructive lung disease and hemorrhagic stroke risk.
Abstract WP251: Sleep Apnea and Early Neurological Deterioration in Acute Ischemic Stroke
Authors: Yoon Cindy W , Rha Joung-Ho , Park Hee-Kwon
Published: June 2021

Background and Purpose:
Evidence of an association between sleep apnea (SA) and early neurological deterioration (END) in acute phase ischemic stroke is scant. We investigated the prevalence of SA and the impact of SA severity on END in acute ischemic stroke (AIS) patients.

Methods:
We prospectively enrolled consecutive AIS patients admitted to our stroke unit within 72 hours of symptom onset. SA severity was assessed with ApneaLink - a validated portable respiratory monitor. SA was defined as an apnea-hypopnea index (AHI) of ≥ 5/hour. END was defined as an incremental increase in the National Institutes of Health Stroke Scale (NIHSS) score by ≥ 1 point in motor power, or ≥ 2 points in the total score within the first week after admission.

Results:
Of the 305 patients studied, 254 (83.3%) patients had SA (AHI ≥ 5/hour), and of these, 114 (37.4%) had mild SA (AHI 5-14/hour), 59 (19.3%) had moderate SA (AHI 15-29/hour), and 81 (26.6%) had severe SA (AHI ≥ 30/hour). Thirty-six (11.8%) patients experienced END: 2 of the 51 (3.9%) patients without SA and 34 of the 254 (14.4%) patients with SA. Multivariable regression analysis showed AHI independently predicted END (odds ratio 1.024; 95% confidence interval 1.006 to 1.042; p = 0.008).

Conclusions:
SA is common in the acute phase of ischemic stroke, and SA severity is associated with the risk of END.
Abstract WP254: Insular Involvement of Ischemic Stroke Suggests a Cardioembolic Mechanism
Authors: Trivedi Tushar , Cutting Shawna , Scher Erica , Chang Andrew , Mac Grory Brian , Tina Burton , Jayaraman Mahesh , McTaggart Ryan , Lord Aaron , Ishida Koto , Rostanski Sara , Dehkharghani Seena , Torres Jose , Frontera Jennifer , Merkler Alexander E , Lerario Mackenzie P , Kamel Hooman , Elkind Mitchell , Furie Karen , Yaghi Shadi
Published: June 2021

Introduction:
The insular cortex controls several aspects of vital function including autonomic regulation, and strokes affecting the insula have been associated with dysautonomia, cardiac dysfunction, and arrhythmias. Previous studies have shown an association between insular strokes, elevated troponin levels, and atrial fibrillation (AF). In this study, we aim to determine the association between cardiac biomarkers and insular involvement of the infarct and hypothesize that insular involvement implicates a cardioembolic source.

Methods:
We abstracted data from a prospective comprehensive stroke center registry of consecutive patients with a discharge diagnosis of acute ischemic stroke who underwent brain imaging (CT or MRI) and work up to determine stroke mechanism. Data included demographics, clinical baseline variables, laboratory tests (including admission troponin level), and transthoracic echocardiographic variables (regional wall motion abnormalities, ejection fraction, and left atrial volume index), and stroke subtype. Multivariable logistic regression models were built to determine associations between AF, and cardiac biomarkers and insular infarcts.

Results:
We identified 1224 patients who met the inclusion criteria; 397 (32.4%) had insular involvement of the infarct. In multivariable models, insular infarcts were associated with AF (adjusted OR 1.73, 95% CI 1.23-2.43, p = 0.001) and left atrial volume index (adjusted OR per standard deviation increase 1.30, 95% CI 1.13-1.49, p = 0.001). There was a trend for association between insular involvement and positive troponin level (adjusted OR 1.45 95% CI 0.91-2.33, p = 0.122) but not with regional wall motion abnormalities (adjusted OR 1.13, 95% CI 0.69-1.84, p = 0.627). Insular involvement was associated with cardioembolic stroke subtype (45.8% vs. 26.7%, p<0.001) but not other stroke subtypes.

Conclusion:
The insular cortex is commonly involved in patients with atrial fibrillation and/or atrial dilation and maybe a neuroimaging biomarker of cardioembolic stroke. Larger studies are needed to confirm this association and test anticoagulation therapy in patients with insular infarcts.
Abstract WP255: Can Normal Electrocardiogram Rule Out Newly Diagnosed Atrial Fibrillation in Ischemic Stroke Patients
Authors: Santucci Joshua , Shimoyama Takashi , Uchino Ken
Published: June 2021

Introduction:
Electrocardiogram (ECG) findings of premature atrial contraction and prolonged PR interval are associated with risk of onset atrial fibrillation (AF) in cryptogenic stroke. We sought to see if normal ECG and AF incidence is incompletely understood.

Methods:
From a prospective single-hospital stroke registry from 2018, we identified ischemic stroke patients who had ECG done on admission for review. We excluded patients with AF on admission ECG, history of AF, and implanted device with cardiac monitoring capability. Normal ECG was interpreted based on the standardized reporting guidelines for ECG studies evaluating risk stratification of emergency department patients. Stroke subtype was diagnosed according to the TOAST classification: large artery atherosclerosis (LAA), small vessel occlusion (SVO), cardioembolism, others/undetermined and embolic stoke of undetermined source (ESUS) criteria. We compared the incidence of newly diagnosed AF during hospitalization and from outpatient cardiac event monitoring between normal and abnormal ECG.

Results:
Of the 558 consecutive acute ischemic stroke patients, we excluded 135 with AF on admission ECG or history of AF and 9 with implanted devices. Of the remaining 414 patients that were included in the study, ESUS (31.2%) was the most frequent stroke subtype, followed by LAA (30.0%), SVO (14.0%), others/undetermined (15.7%), and cardioembolism (9.2%). Normal ECG was observed in 125 patients (30.2%). Cardioembolic subtype was less frequent in the normal versus abnormal ECG group (1.6% vs. 12.5%, p<0.001). New AF was detected in 17/414 patients (4.1%) during hospitalization. Of these 17 patients, none had normal ECG (0/125) and all had abnormal ECG (17/289, 5.9%) (p=0.002). After discharge, of 111 patients undergoing 4-week outpatient cardiac monitoring, new AF was detected in 16 (14.4%). Of these 16 patients, only 1 had a normal ECG (1/35, 2.9%) while 15 had abnormal ECG (15/76, 19.7%) (p=0.02).

Conclusions:
Normal ECG at admission for acute ischemic stroke is associated with low likelihood of detection of new atrial fibrillation in either the inpatient or outpatient setting.
Abstract WP257: Therapeutic Anti Coagulation and Ischemic Stroke Mechanism in Atrial Fibrillation Exploring Risk Factors
Authors: Al-Salaimeh Ayman , Bradley Bruce , Gupta Vedant , Dobbs Michael , Henninger Nils , Goldstein Larry B
Published: June 2021

Background:
Ischemic stroke occurs in setting of AF despite adequate treatment because of both cardiac and non-cardiac causes. We hypothesized that certain clinical , and cardiac characteristics would increase the likelihood of cardio -embolic stroke(CES) in therapeutically anticoagulated patients with AF

Methods:
We reviewed the records of all adults who were adequately anticoagulated with warfarin or a DOAC(if information was available), and admitted to either the University of Kentucky or University of Massachusetts medical School with a diagnosis of ischemic stroke or transient ischemic attack between 01/01/2011 -06/30/2016. Stroke mechanism (CES vs non CES) using ASCOD criteria was determined by a vascular neurologist masked to the echocardiographic results. Categorical variables were analyzed with Chi square or Fisher exact test as appropriate. Continuous variables were analyzed using t test. P value <.05 was considered significant. Stepwise logistic regression was used to identify variable independently associated with CES

Results:
110 patients (68 patients with CES and 42 with non- CES ) were identified. In univariable analyses, CHF was more common in CES group (45% vs 23.8%, p=0.026) , EF was lower in CES group (49% vs 60% , p .00008) , history of PAD or Carotid disease were more common in non CES group (78% vs 50%, p .01) , also total cholesterol on admission was higher in the non CES group (158.5 vs 132.3 mg/dl, p .002) .other variables did not reach statistical significance ( see table) on multiple logistic regression only EF , total cholesterol and history of PAD/Carotid disease maintained statistical significance (.043, 0.013, and 0.022, respectively).

Conclusion:
Patients with CES despite therapeutic anticoagulation had lower EF, were less likely to have extensive atherosclerotic disease , and had lower total cholesterol compared to those with non- CES. Larger prospective studies are required to confirm these findings
Abstract WP258: Effectiveness of Detection Asymptomatic Episodes of Atrial Fibrillation in Heart Failure Patients With Cardioverter Defibrillator
Authors: Dominik Barbara , Zorawski Wojciech , Kowalik Ilona , Ciesielski Adam , Mitkowski Przemyslaw
Published: June 2021

Introduction:
Implantable cardioverter defibrillators due to the possibility of continuous recording of intracardiac electrograms can detect episodes of atrial fibrillation. In practice, this allows better identification of patients with asymptomatic AF episodes, thus increasing the proportion of patients who may benefit from pharmacological prophylaxis of thromboembolic events, particularly stroke.

Hypothesis:
If intracardiac electrogram analysis should be part of each visit carried out in patients with implantable cardioverter defibrillator, how much of detected episodes of atrial fibrillation is asymptomatic.

Methods:
The study included 174 consecutive outpatient cases with heart failure, sinus rhythm and implanted Cardioverter Defibrillator and Cardiac Resynchronisation Therapy with Defibrillator. Control visits with analysis intracardiac electrograms records occurred every three months. Each AF episode stored in the device’s memory lasting at least 30 seconds was considered an episode of atrial fibrillation. A symptomatic episode was considered when arrhythmia led to ICD shock, heart deterioration, collapse or fainting, palpitations, weakness, chest pain or shortness of breath accompanied by a feeling of irregular heartbeat. During mean follow-up of 20 months, 901 visits were carried out. 147 patients had at least one year of follow-up.

Results:
Atrial fibrillation (AF) episodes in the study occurred in 54 (31.0%) patients. Of the 241 atrial fibrillation episodes recorded in the device’s memory, 71.4% were asymptomatic. There was no statistically significant difference in the incidence of new episodes of atrial fibrillation (P = 0.384) in the study group with a history of stroke or transient ischemic episodes during follow-up. However, asymptomatic AF episodes were more common in stroke patients (P = 0.0074). In the time of observation in the whole group of patients there were no new strokes and transient ischemic attack.

Conclusion:
In conclusion, detection of asymptomatic atrial fibrillation episodes based on intracardiac electrocardiogram records is effective method. In the study group, such episodes were up 71.4% of all newly detected AF episodes.
Abstract WP259: Risk of Atrial Fibrillation in Patients With Patent Foramen Ovale: A Meta-Analysis
Authors: Chen Jessie , Thijs Vincent
Published: June 2021

Background:
Case-control studies have shown that patent foramen ovale (PFO) is strongly associated with ischaemic stroke, especially in younger patients and embolic stroke of undetermined source. A commonly encountered clinical question is whether undetected atrial fibrillation (AF) is the alternate cause for embolic stroke in such patents.

Aim:
This study aims to evaluate the risk of AF in patients with PFO, and explore clinical factors that might predict detection of AF in this population.

Methods:
Studies were identified by systematically searching EMBASE and MEDLINE databases on 11
th
July, 2019. The primary outcome was the risk of atrial fibrillation in patients with PFO compared with those who did not. Outcomes were pooled using a random-effects model using the method of DerSimonian &Laird. Methods used for AF detection in included studies (unspecified, history/medical records review, ECG, Holter monitor, or loop recorder) were noted.

Results:
A total of 12 studies and 12,764 patients were included. The average age was 63.2 years and 39.1% were female. There was a reduced risk of AF detection in patients with PFO compared to those without (OR 0.471, 95% confidence interval, 0.313-0.630, p<0.001). There was evidence of moderate heterogeneity. Univariable random-effects meta-regression by mean patient age, prevalence of hypertension and diabetes, and method of AF detection did not detect an association with risk of AF. Meta-regression by PFO detection technique suggested that studies using transoesophageal echocardiogram for PFO detection reported higher risk of AF(1.48, 95% confidence interval 1.15-1.91, p=0.006).

Conclusion:
The presence of PFO in patients with ischaemic stroke/TIA is associated with lower risk of AF detection compared to those without PFO.
Abstract WP260: The Left Atrial Appendage Morphology Improves Prediction of Appendage Stagnant Flow and Stroke Risk in Patients With Atrial Fibrillation Using a Simple Classification System
Authors: Yaghi Shadi , Chang Andrew , Ignacio Gian , Scher Erica , Panda Nikhil , Chu Antony , Wu Michael , Lord Aaron , Mac Grory Brian , Furie Karen , Elkind Mitchell , Atalay Michael , Song Christopher
Published: June 2021

Background and Purpose:
Previously we proposed a simple classification system of the left atrial appendage (LAA) morphology, with low risk (LAA-L) defined as one lobe with an acute angle bend arising from the proximal or middle portion and high risk (LAA-H) defined as all other morphologies. We aim to determine the association between LAA morphology (using both classification systems), LAA flow velocity, and stroke rates.

Methods:
We analyzed consecutive patients with atrial fibrillation (AF) selected for ablation who underwent cardiac CT angiography and transesophageal echocardiogram. The primary correlates were LAA-H and non-chicken wing (NCW) LAA morphology. The primary outcome was the composite endpoint of history of ischemic stroke/TIA or non-lacunar infarct on neuroimaging. Adjusting for CHADS2Vasc score, multivariable models were used to determine associations between LAA morphology and composite outcomes.

Results:
We identified 379 patients; the primary endpoint occurred in 32/379 patients (8.4%). LAA-H (adjusted OR 3.63, 95% CI 1.44-9.14) and NCW LAA morphology (adjusted OR 2.52, 95% CI 1.15-5.53) were associated with the primary endpoint. LAA flow velocity ≤20 cm/s was more common in LAA-H vs. LAA-L (9.6% vs. 2.8%, p = 0.019), but not in NCW vs. CW LAA morphology (9.7% vs. 3.7%, p = 0.054).

Conclusion:
The LAA H/L morphological classification system may be superior to the current system in risk stratifying patients with AF and correlates better with impaired LAA flow dynamics.
Abstract WP264: Frequency of Hypercoagulability in Patients With Embolic Stroke of Undetermined Source and Patent Foramen Ovale
Authors: Liu Michael , Rangaraju Srikant , Duncan Alexander , Belagaje Samir , Belair Trina , Henriquez Laura , Nahab Fadi
Published: June 2021

Introduction:
Patent foramen ovale (PFO) is more commonly found in patients with cryptogenic stroke and paradoxical embolism is commonly assumed to be the primary mechanism. Our objective was to determine the frequency of hypercoagulability in cryptogenic stroke patients and PFO.

Methods:
Consecutive patients with embolic stroke of undetermined source (ESUS) seen at the Emory Clinic from January 1, 2017 to June 30, 2019 who underwent echocardiogram with bubble study and markers of coagulation and hemostatic activation (MOCHA) testing (serum d-dimer, prothrombin fragment 1.2, thrombin-antithrombin complex, fibrin monomer) were included; abnormal MOCHA was defined as ≥ 2 elevated markers. Venous thromboembolism, malignancy, other defined hypercoagulable state, and the composite outcome were assessed at routine follow-up and compared across groups based on PFO status.

Results:
Of 172 patients (mean age 63 ± 16 years, 60% female), 40 (23%) had a PFO. Compared to the PFO- group, the PFO+ group was younger (p=<0.001), less likely to have hypertension (p<0.001) and diabetes (p=0.011), and had a higher ROPE score (p=0.007) (Table 1). There was no difference in the frequency of abnormal MOCHA between groups and the composite outcome was less frequent in PFO+ versus PFO- patients (p=0.017). In the subgroup of patients <60 years old, there was no difference in the frequency of abnormal MOCHA and the composite outcome.

Conclusion:
Hypercoagulability as measured by MOCHA was not associated with the presence of PFO in ESUS patients. Based on our results, ESUS patients should undergo a detailed evaluation for alternative causes of stroke other than paradoxical embolism.
Abstract WP273: Radiologic Characteristic of Perioperative Large Vessel Occlusions in Patients Who Underwent Transcatheter and Surgical Valve Replacement
Authors: Zhang Lucy Q , Santucci Joshua , Shimoyama Takashi , Handshoe L. Samuel , Mulpur Bhagee , Uchino Ken
Published: June 2021

Body Introduction:

Ischemic stroke is a known perioperative complication of both transcatheter and surgical aortic valve replacement (TAVR and SAVR). We compared large vessel occlusions (LVO) in ischemic strokes after TAVR and SAVR to those of spontaneous ischemic strokes) and examined radiographic characteristic of their occlusive clots.

Methods:
Between January 2012 to December 2017, 9069 patients underwent TAVR or SAVR at a single tertiary center. Perioperative stroke was defined as a stroke that occurred within14 days of surgery. Exclusions were presence of extracorporeal membrane oxygenation and ventricular assist devices, as well as concurrent cardiac procedures except coronary revascularization. LVOs were detected using CTA or MRA, defined as internal carotid, middle cerebral, basilar or posterior cerebral artery occlusions. The site of occlusion was matched to its location on non-contrast CT brain. Control occlusions were LVOs of cardio embolus and large artery atherosclerosis from a single-center stroke registry. Tissue density of occlusive clots was measured in Hounsfield Unit (HU). We compared clot densities of perioperative LVOs to control LVOS.

Results:
Of 157 patients with perioperative stroke during the study period, 107 met inclusion criteria for analysis. LVO represented 16.8% (n=18) of perioperative strokes in patients who underwent TAVR or SAVR. Frequencies of LVOs were similar between TAVR (6/28, 21.4%) and SAVR (12/79, 21.4%, p=0.45). Occlusions involved ICA in 5 patients, M1 MCA in 8, M2 in 3, P1 PCA in 1, and basilar in 1. Clot density could be measured in 15 patients. Clots from perioperative LVOs were more dense than clots of LVOs from patients with known cardioembolism (median 53.5 HU in perioperative, 40 HU in cardioembolism, p<0.001), but were similar to LVOs due to large artery atherosclerosis (median 55.5 HU, p=0.57). Four perioperative LVOs were noted to be exceptionally dense (mean 226.8 HU, SD= 59) and separated themselves from others in regard to clot density on CT.

Conclusion:
The heterogeneity of LVOs can be appreciated on CT brain because of differences in clot density. These differences may be helpful in determining stroke etiology.
Abstract WP274: No Improvement in Emergency Medical Services Use by Stroke Patients From 1999-2015: A Population-Based Study
Authors: Li James L , Sucharew Heidi , Alwell Kathleen , Broderick Joseph P , Coleman Elisheva , De Los Rios La Rosa Felipe , Demel Stacie L , Ferioli Simona , Flaherty Matthew L , Jasne Adam , Khatri Pooja , Kissela Brett M , Mackey Jason , Martini Sharyl , Mistry Eva , Moomaw Charles J , Slavin Sabreena J , Star Michael , Walsh Kyle , Woo Daniel , McMullan Jason T , Kleindorfer Dawn O , Adeoye Opeolu
Published: June 2021

Objective:
We sought to assess whether the proportion of stroke patients who utilized Emergency Medical Services (EMS) has changed over time in a population-based epidemiological study.

Methods:
Stroke and transient ischemic attack (TIA) patients were identified in a population of 1.3 million in the Cincinnati area from data in 1999, 2005, 2010, and 2015. Patient charts and EMS records were analyzed by research nurses and reviewed by study physicians. This analysis excluded strokes/TIAs that occurred while in a hospital, out of town, during EMS transport, or at unknown location. Patients with unknown EMS utilization, stroke severity, baseline pre-stroke disability, race, stroke type, or under age 18 were excluded. Proportion of EMS utilization by stroke patients was calculated and Cochran-Armitage Trend Test was used to analyze trends in EMS utilization over time. Multivariable logistic regression was used to determine the association between age, race, sex, prior stroke, stroke type, where the stroke occurred, stroke severity, and pre-stroke disability with EMS use.

Results:
In 1999, 2005, 2010 and 2015, 2968 of 3860, 2900 of 3643, 3010 of 3503, and 3327 of 3767 stroke cases were included, respectively. EMS use by stroke patients did not change significantly over time (52%, 51%, 52%, 53%, p=0.12 for trend). In 1999 and 2015, age, pre-stroke disability, stroke severity, hemorrhagic stroke and stroke occurring at work were significantly associated with EMS use. Race, sex, and prior stroke were not. Slight variation in associations occurred in 2005 and 2010, with stroke at work not reaching significance in 2005 and 2010, and pre-stroke disability not reaching significance in 2005.

Conclusion:
EMS use by stroke patients in our population did not change from 1999 to 2015. With the recent advances in treatment options for stroke, novel and effective approaches to increase EMS use are warranted.
Abstract WP280: A Potential Scoring System to Predict Infarct Progression During Inter Facility Transfer of Patients for Endovascular Thrombectomy Evaluation
Authors: Reddy Sujan Teegala , Friedman Elliott , Wu Tzu-Ching , Zhang Xu , Zhang Jing , Arevalo Octavio , Sitton Clark , Savitz Sean
Published: June 2021

Introduction:
Current guidelines recommend CT ASPECTS≥6 as eligibility criteria for endovascular thrombectomy (EVT), a proven therapy for anterior circulation large vessel occlusion (ACLVO). Infarct progression during inter-facility transfer can render many patients ineligible for EVT. We developed a score utilizing clinical and imaging variables to predict infarct progression.

Methods:
Patients with ACLVO transferred from a referring hospital (RH) to our EVT capable center between August 2015 and December 2018 were reviewed. Significant predictors (p<0.10) of infarct progression, defined as CT ASPECTS of ≥6 at RH to <6 at hub, were identified using a logistic regression model. Regression coefficient estimates were used to score selected variables. The optimal cut-point was selected based on evaluated Youden index.

Results:
A total of 132 patients were analyzed. Score ranged from 0 to theoretical limit 18 (table 1): CTA collateral score (2/3/4=0, 0/1=3), Clot location (not ICA/M2=0, M2=2, ICA/M1=3), NIHSS (0-14=0, ≥15=5), use of antiplatelet by history (Yes=0, No=3), CT ASPECTS at RH (10=0, 6-9=2). Patients with score of ≥10.0 were more likely to have infarct progression (OR=22.15, 95% CI 4.99 - 98.35, p<0.001).

Conclusions:
Our score utilizing clinical and imaging variables provides information on which patients with ACLVO may undergo infarct progression during inter-facility transfer. We plan to externally validate our findings in another hub and spoke network. This score may potentially aid decisions to develop stroke systems of care to triage patients with ACLVO within hub and spoke networks.
Abstract WP285: Impact of Endovascular Treatment on the Patterns of Interhospital Transfer of Stroke Patients in California
Authors: Zachrison Kori S , Onnela Jukka-Pekka , Schwamm Lee H , Li Sijia , Espinola Janice A , Camargo Carlos A , Hsia Renee Y
Published: June 2021

Background:
Optimized stroke systems of care can enable equitable access to timely care, including endovascular thrombectomy (EVT). Yet how hospitals are connected in the care of stroke patients is not well-characterized. Given that EVT is only available in specialized centers, stroke systems and patient transfer patterns may have evolved after the 2015 publication of EVT benefit.

Primary objective:
to map the stroke patient transfer network in California and to determine whether it changed after 2015.

Methods:
We analyzed California data including every nonfederal hospital admission from pre- (2010-2014) and post-2015 (2016-2017). ICD-9, ICD-10, and DRG codes identified ischemic stroke (IS) hospitalizations. Connections between any 2 hospitals were based on the transfer of
>
5 IS patients between them/year. t-tests compared the patient transfer maps pre- vs post-2015 on descriptive network measures: number of hospitals, transfer connections, and patients shared in transfer, and distance traveled in transfer. A hierarchical logistic regression model assessed whether patients were more frequently transferred to EVT-capable hospitals after 2015, adjusting for patient- and hospital-level factors, including a time-by-distance interaction.

Results:
Among 385,799 IS hospitalizations, 15,522 (4.0%) were transferred. After 2015, patients traveled longer distances in transfer (25.1 vs 28.4 miles, p<0.001) (Figure). The proportion of patients transferred and the number of EVT centers were stable, but, after 2015, patients were more frequently transferred to EVT centers and travelled longer distance to do so (post-2015 OR 3.0, 95% CI 2.5-3.5; distance OR 1.044/mile, 95% CI 1.04-1.05; OR for interaction 1.01, 95% CI 1.003-1.02).

Conclusion:
The California stroke transfer network significantly changed after the 2015 publication of benefit for EVT, with increased likelihood of transfer to EVT centers and longer distances traveled in transfer.
Abstract WP287: Modeling the Impact of Pre-Hospital Triage on a True Life Drip and Ship Thrombectomy Patient Cohort
Authors: Giovanni Brian , Rubenstein Liorah , Majidi Shahram , Stein Laura , Fifi Johanna T
Published: June 2021

Introduction:
Patients with emergent large vessel occlusions (ELVO) are often brought to the closest hospital, possibly given intravenous tPA, and transferred to a hospital capable of performing endovascular intervention. This results in significant delays to thrombectomy and worse patient outcomes when compared with patients brought directly to endovascular centers. In New York City, the pre-hospital system has created a protocol for EMS to use a clinical screening tool to triage stroke patients, and bring those with suspected ELVO directly to comprehensive (CSC) or thrombectomy-capable stroke centers (TSC).

Objective:
To model the impact of EMS triage protocols on administration of tPA, initiation of endovascular therapy, and recanalization of large vessel occlusions using a real life cohort of thrombectomy patients.

Methods:
Using our system wide prospectively collected stroke database, we selected a consecutive cohort of 80 thrombectomy patients who were brought by EMS to a primary stroke center then transferred to a TSC or CSC for endovascular intervention. The patient’s initial EMS pickup address was used to calculate the closest TSC or CSC using Google Maps API. Driving time was calculated based on traffic patterns at the time of pickup. Using data from a cohort of 69 consecutive patients that were brought directly to a TSC or CSC by EMS and underwent endovascular intervention, we derived median door to needle and door to groin puncture times. These times, combined with calculated driving distance, were used to model the timing of treatment in the triage model. Timings in the actual cohort versus the model were compared.

Results:
In the “actual” drip and ship cohort versus our model, first medical contact (FMC) to endovascular center door was 211 versus 32 minutes (p<0.01), first medical contact (FMC) to tPA was 91 versus 81 minutes (p=0.07), FMC to groin puncture was 265 versus 154 minutes (p<0.01), and FMC to TICI2B+ recanalization was 313 versus 205 minutes (p<0.01).

Conclusions:
Modeled EMS pre-hospital triage of ELVO patients results in a significant decrease in endovascular treatment times without change in tPA times. As triage tools increase in sensitivity and specificity, EMS triage protocols stand to improve patient outcomes.