Racial-Ethnic disparities in stroke prevalence among patients with heart failure

Racial-ethnic disparities exist in the prevalence and outcomes of heart failure (HF) and are presumed to be related to differences in cardiovascular risk factor burden and control. There is little data on stroke disparities among patients with HF or the factors responsible. We hypothesized disparities in stroke prevalence exist among patients with HF in a manner not fully explained by burden of cardiovascular disease. We analyzed data from the National Health and Nutrition Examination Survey (1999-2014). Cardiovascular profiles were compared by race/ethnicity. Using survey-weighted models, effect modification of the relationship between HF and stroke by race/ethnicity was examined adjusting for cardiovascular profiles. Of 40,437 participants, 2.5 % had HF. The HF cohort had a greater proportion of White and Black participants (77 % vs 74 % and 15 % vs 12 %, respectively) and fewer participants of Hispanic ethnicity (8 % vs 14 %). Stroke was 8 times more prevalent in HF (19.6 % vs 2.3 %, <0.001). Among individuals with HF, race-ethnic differences were identified in the prevalence and mean values of vascular risk factors but were largely driven by higher rates in Black participants. There was significant interaction between HF and race/ethnicity; HF increased the odds of stroke over 7-fold in participants of Hispanic ethnicity (aOR: 7.84; 95 % CI: 4.11-15.0) but to a lesser extent in Black and White participants (Black aOR: 2.49; 95 % CI: 1.72-3.60; White aOR: 3.36; 95 % CI: 2.57-4.40). People of Hispanic ethnicity with HF have a disproportionately higher risk of stroke in a manner not fully explained by differences in vascular risk profiles.

Apixaban to Prevent Recurrence After Cryptogenic Stroke in Patients With Atrial Cardiopathy: The ARCADIA Randomized Clinical Trial

Importance

Atrial cardiopathy is associated with stroke in the absence of clinically apparent atrial fibrillation. It is unknown whether anticoagulation, which has proven benefit in atrial fibrillation, prevents stroke in patients with atrial cardiopathy and no atrial fibrillation.

Objective

To compare anticoagulation vs antiplatelet therapy for secondary stroke prevention in patients with cryptogenic stroke and evidence of atrial cardiopathy.

Design, Setting, and Participants

Multicenter, double-blind, phase 3 randomized clinical trial of 1015 participants with cryptogenic stroke and evidence of atrial cardiopathy, defined as P-wave terminal force greater than 5000 μV × ms in electrocardiogram lead V1, serum N-terminal pro-B-type natriuretic peptide level greater than 250 pg/mL, or left atrial diameter index of 3 cm/m2 or greater on echocardiogram. Participants had no evidence of atrial fibrillation at the time of randomization. Enrollment and follow-up occurred from February 1, 2018, through February 28, 2023, at 185 sites in the National Institutes of Health StrokeNet and the Canadian Stroke Consortium.

Interventions

Apixaban, 5 mg or 2.5 mg, twice daily (n = 507) vs aspirin, 81 mg, once daily (n = 508).

Main Outcomes and Measures

The primary efficacy outcome in a time-to-event analysis was recurrent stroke. All participants, including those diagnosed with atrial fibrillation after randomization, were analyzed according to the groups to which they were randomized. The primary safety outcomes were symptomatic intracranial hemorrhage and other major hemorrhage.

Results

With 1015 of the target 1100 participants enrolled and mean follow-up of 1.8 years, the trial was stopped for futility after a planned interim analysis. The mean (SD) age of participants was 68.0 (11.0) years, 54.3% were female, and 87.5% completed the full duration of follow-up. Recurrent stroke occurred in 40 patients in the apixaban group (annualized rate, 4.4%) and 40 patients in the aspirin group (annualized rate, 4.4%) (hazard ratio, 1.00 [95% CI, 0.64-1.55]). Symptomatic intracranial hemorrhage occurred in 0 patients taking apixaban and 7 patients taking aspirin (annualized rate, 1.1%). Other major hemorrhages occurred in 5 patients taking apixaban (annualized rate, 0.7%) and 5 patients taking aspirin (annualized rate, 0.8%) (hazard ratio, 1.02 [95% CI, 0.29-3.52]).

Conclusions and Relevance

In patients with cryptogenic stroke and evidence of atrial cardiopathy without atrial fibrillation, apixaban did not significantly reduce recurrent stroke risk compared with aspirin.

Trial Registration

ClinicalTrials.gov Identifier: NCT03192215.

Relationships of Hematocrit With Chronic Covert and Acute Symptomatic Lacunar Ischemic Lesions

BACKGROUND AND OBJECTIVES

Red blood cell (RBC) concentrations are known to associate with ischemic stroke. It is unclear whether RBC concentrations associate specifically with small vessel disease lacunar infarcts. We investigated the hypothesis that RBC concentrations associate with both chronic covert and acute symptomatic brain MRI lacunar infarcts.

METHODS

A cross-sectional observational analysis was performed across 2 cohorts with available hematocrit (as the assessment of RBC concentration exposure) and MRI outcome data. The primary setting was a population-based cohort of stroke-free, older adult (>50 years) participants from the Northern Manhattan Study (NOMAS) enrolled between 2003 and 2009. A second replication sample consisted of patients admitted with acute stroke and enrolled into the Columbia Stroke Registry (CSR) between 2005 and 2020. Associations of hematocrit with (1) chronic, covert lacunar infarcts and (2) symptomatic (i.e., acute) lacunar strokes were separately assessed from the NOMAS and CSR cohorts, respectively, using general additive models after adjusting for relevant covariates.

RESULTS

Of 1,218 NOMAS participants analyzed, 6% had chronic, covert lacunar infarcts. The association between hematocrit and these covert lacunar infarcts was U-shaped (χ2 = 9.21 for nonlinear associations; p = 0.03), with people with hematocrit extremes being more likely to have covert lacunar infarcts. Of the 1,489 CSR patients analyzed, 23% had acute lacunar strokes. In this sample, only the relationships of increased hematocrit concentrations and lacunar strokes were replicated (adjusted coefficient β = 0.020; SE = 0.009; p = 0.03).

DISCUSSION

We identified relationships of hematocrit with MRI lacunar infarcts in both stroke-free and ischemic stroke cohorts, respectively. The relationship between increased hematocrit concentrations with lacunar infarcts was replicated in both cohorts. Further studies are required to clarify the mechanisms behind the relationships of hematocrit with ischemic cerebral small vessel disease.

Cerebral blood flow and neurocognition in patients undergoing transcatheter aortic valve replacement for severe aortic stenosis

Aims

Aortic valve stenosis (AS) results in higher systolic pressure to overcome resistance from the stenotic valve, leading to heart failure and decline in cardiac output. There has been no assessment of cerebral blood flow (CBF) association with neurocognition in AS or the effects of valve replacement. The goal was to determine if AS is associated with altered cerebral haemodynamics and impaired neurocognition, and whether transcatheter aortic valve replacement (TAVR) improves haemodynamics and cognition.

Methods and results

In 42 patients with planned TAVR, transcranial Doppler (TCD) assessed bilateral middle cerebral artery (MCA) mean flow velocities (MFVs); abnormality was <34.45 cm/s. The neurocognitive battery assessed memory, language, attention, visual-spatial skills, and executive function, yielding a composite Z-score. Impairment was <1.5 SDs below the normative mean. The mean age was 78 years, 59% Male, and the mean valve gradient was 46.87 mm/Hg. Mean follow-up was 36 days post-TAVR (range 27-55). Pre-TAVR, the mean MFV was 42.36 cm/s (SD = 10.17), and the mean cognitive Z-score was -0.22 SDs (range -1.99 to 1.08) below the normative mean. Among the 34 patients who returned after TAVR, the MFV was 41.59 cm/s (SD = 10.42), not different from baseline (P = 0.66, 2.28-3.67). Post-TAVR, average Z-scores were 0.17 SDs above the normative mean, not meeting the pre-specified threshold for a clinically significant 0.5 SD change.

Conclusion

Among patients with severe AS, there was little impairment of MFV on TCD and no correlation with cognition. Transcatheter aortic valve replacement did not affect MFV or cognition. Assumptions about diminished CBF and improvement after TAVR were not supported.

Dynamic cerebral autoregulation in postpartum individuals with and without preeclampsia

BACKGROUND

Changes in dynamic cerebral autoregulation (DCA) may contribute to postpartum maternal cerebrovascular complications after preeclampsia. We hypothesized that DCA is impaired in the first week postpartum after diagnosis of preeclampsia with severe features (PSF), compared with normotensive postpartum individuals and healthy non-pregnant female volunteers.

METHODS

We measured DCA within seven days after delivery in individuals with and without PSF, using transcranial Doppler and continuous arterial blood pressure monitoring with finger plethysmography. Historical data from 28 healthy female non-pregnant volunteers, collected using the same methods, were used for comparison. We used generalized harmonic wavelets to estimate autoregulation parameters (phase shift and gain) in very low frequency and low frequency bands, with lower phase shift and higher gain indicating impaired DCA function. We compared DCA parameters between the three groups using the Kruskal Wallis test.

RESULTS

A total of 69 postpartum participants contributed data, of whom 49 had preeclampsia with severe features. Median phase shifts in both postpartum groups were higher compared with historical controls across all frequency ranges (p = 0.001), indicating faster autoregulatory response. Gain was higher in both postpartum groups than in historical controls across all frequency ranges (p = 0.04), indicating impaired dampening effect.

CONCLUSION

We found that postpartum individuals, regardless of preeclampsia diagnosis, had higher phase shifts and higher gain than healthy non-pregnant/postpartum female volunteers. Our results suggest hyperdynamic DCA with impaired dampening effect in the first week postpartum, regardless of preeclampsia diagnosis.

The role of intracranial artery calcification (IAC) in stroke subtype and risk of vascular events

OBJECTIVE

To test the hypothesis that intracranial arterial calcification (IAC) is associated with intracranial large artery stenosis (ILAS) and a higher risk of vascular events and mortality.

METHOD

We leveraged data from two cohorts, the New York-Presbyterian Hospital/Columbia University Irving Medical Center Stroke Registry Study (NYP/CUIMC-SRS) and the Northern Manhattan Study (NOMAS) to test our hypotheses. We measured IAC using CT scans of participants in both cohorts and expressed IAC as present (vs not) and in tertiles. For the CUIMC-SRS, demographic, clinical and ILAS status was collected retrospectively. In NOMAS, we used research brain MRI and MRA to define asymptomatic ILAS and covert brain infarcts(CBI). We built models adjusted for demographics and vascular risk factors for cross-sectional and longitudinal analyses.

RESULTS

Cross-sectionally, IAC was associated with ILAS in both cohorts (OR 1.78, 95% CI: 1.16-2.73 for ILAS-related stroke in the NYP/CUIMC-SRS and OR 3.07, 95%CI 1.13-8.35 for ILAS-related covert brain infarcts in NOMAS). In a meta-analysis of both cohorts, IAC in the upper (HR 1.25, 95%CI 1.01-1.55) and middle tertile (HR 1.27, 95%CI 1.01-1.59) was associated with higher mortality compared with participants with no IAC. There were no longitudinal associations between IAC and risk of stroke or other vascular events.

CONCLUSION

In these multiethnic populations, IAC is associated with symptomatic and asymptomatic ILAS as well as higher mortality. IAC may be a useful marker of higher mortality, the role of IAC as an imaging marker of risk of stroke is less certain.

Inequities in Telemedicine Use Among Patients With Stroke and Cerebrovascular Diseases

Background and Objectives

In response to the COVID-19 pandemic, outpatient stroke care delivery was rapidly transformed to outpatient evaluation through video (VTM) and telephone (TPH) telemedicine (TM) visits around the world. We sought to evaluate the sociodemographic differences in outpatient TM use among stroke patients.

Methods

We conducted a retrospective chart review of outpatients evaluated at 3 tertiary stroke centers in the early period of the pandemic, 3/16/2020 through 7/31/2020. We compared the use of TM by patient characteristics including age, sex, race/ethnicity, insurance status, stroke type, patient type, and site. The association between TM use and patient characteristics was measured using the relative risk (RR) from a modified Poisson regression, and site-specific effects were controlled using a multilevel analysis.

Results

A total of 2,024 visits were included from UTHealth (n = 878), MedStar Health (n = 269), and Columbia (n = 877). The median age was 64 [IQR 52–74] years, and 53% were female. Approximately half of the patients had private insurance, 36% had Medicare, and 15% had Medicaid. Two-thirds of the visits were established patients. TM accounted for 90% of total visits, and the use of TM over office visits was primarily associated with site, not patient characteristics. TM utilization was associated with Asian and other/unknown race. Among TM users, older age, Black race, Hispanic ethnicity, and Medicaid insurance were associated with lower VTM use. Black (aRR 0.88, 95% CI 0.86–0.91,p< 0.001) and Hispanic patients (aRR 0.92, 95% CI 0.87–0.98,p= 0.005) had approximately 10% lower VTM use, while Asian patients (aRR 0.98, 95% CI 0.89–1.07,p= 0.59) had similar VTM use compared with White patients. Patients with Medicaid were less likely to use VTM compared with those with private insurance (aRR 0.86, 95% CI 0.81–0.91,p< 0.001).

Discussion

In our diverse cohort across 3 centers, we found differences in TM visit type by race and insurance early during the COVID-19 pandemic. These findings suggest disparities in VTM access across different stroke populations. As VTM remains an integral part of outpatient neurology practice, steps to ensure equitable access are essential.

Reduced-order modeling and analysis of dynamic cerebral autoregulation via diffusion maps

OBJECTIVE

A data-driven technique for parsimonious modeling and analysis of dynamic cerebral autoregulation (DCA) is developed based on the concept of diffusion maps. Specifically, first, a state-space description of DCA dynamics is considered based on arterial blood pressure (ABP), cerebral blood flow velocity (CBFV), and their time derivatives. Next, an eigenvalue analysis of the Markov matrix of a random walk on a graph over the dataset domain yields a low-dimensional representation of the intrinsic dynamics. Further dimension reduction is made possible by accounting only for the two most significant eigenvalues. The value of their ratio indicates whether the underlying system is governed by active or hypoactive dynamics, indicating healthy or impaired DCA function, respectively. We assessed the reliability of the technique by considering healthy individuals and patients with unilateral ICA stenosis or occlusion. We computed the sensitivity of the technique to detect the presumed side-to-side difference in the DCA function of the second group (assuming hypoactive dynamics on the occluded or stenotic side), using McNemar's chi square test. The results were compared with transfer function analysis (TFA). The performance of the two methods was also compared under the assumption of missing data.

MAIN RESULTS

Both diffusion maps and TFA suggested a physiological side-to-side difference in the DCA of ICA stenosis or occlusion patients with a sensitivity of 77% and 58%, respectively. Further, both two methods suggested the difference between the occluded or stenotic side and any two sides of the healthy group. However, the diffusion maps captured additional difference between the unoccluded side and the healthy group, that TFA did not. Furthermore, compared to TFA, diffusion maps exhibited superior performance when subject to missing data.

SIGNIFICANCE

The eigenvalues ratio derived using the diffusion maps technique can be used as a reliable and robust biomarker for assessing how active the intrinsic dynamics of the autoregulation is and for indicating healthy versus impaired DCA function.

Abstract WP188: Relationships Of Hematocrit With Asymptomatic And Symptomatic Lacunar Ischemic Lesions

Introduction: Hematocrit at both low and high extremes can result in both hypoxia and thrombosis respectively. While both scenarios may predispose to ischemia, it is unclear whether hematocrit associates with small vessel cerebrovascular lacunar infarcts.

Hypothesis: Hematocrit levels will associate with both asymptomatic and symptomatic cerebrovascular lacunar infarcts in stroke-free participants and ischemic stroke patients, respectively.

Methods: A cross sectional observational analysis of a prospective, population-based cohort study of stroke-free, older adult (>50) participants from the Northern Manhattan study (NOMAS) receiving baseline hematocrit testing and MRI between 2003-2008 were analyzed. A second, single center prospective cohort of admitted adult ischemic stroke patients receiving baseline hematocrit testing and MRI between 2005-2018 was evaluated. Associations of hematocrit with covert, asymptomatic chronic lacunar infarcts from stroke-free participants in NOMAS were assessed using general additive models after adjusting for relevant covariates. Separate analyses were performed to assess associations of hematocrit with symptomatic acute lacunar infarct stroke etiology using similar adjusted models for patients admitted and enrolled into the ischemic stroke registry.

Results: Of 1218 NOMAS participants analyzed, 6% had covert chronic lacunar infarcts. The association between hematocrit and covert chronic lacunar infarcts was U-shaped (X2: 9.21; p-value: 0.03). In the 1489 patients from the ischemic stroke registry, 23% were identified to have symptomatic acute lacunar infarcts. Linear relationships were identified with higher hematocrit and symptomatic acute lacunar infarct etiology (adjusted coefficient beta: 0.020; standard error: 0.009; p=0.03).

Conclusions: We identified relationships of hematocrit with both asymptomatic and symptomatic lacunar infarcts in both stroke-free and ischemic stroke cohorts, respectively. There may be a relevant role of red blood cell volumes with ischemic cerebral small vessel disease pathophysiology. However, further studies are required to clarify the mechanisms behind these relationships.

Adaptive Wall Shear Stress Imaging in Phantoms, Simulations and In Vivo

WSS measurement is challenging since it requires sensitive flow measurements at a distance close to the wall. The aim of this study is to develop an ultrasound imaging technique which combines vector flow imaging with an unsupervised data clustering approach that automatically detects the region close to the wall with optimally linear flow profile, to provide direct and robust WSS estimation. The proposed technique was evaluated in phantoms, mimicking normal and atherosclerotic vessels, and spatially registered Fluid Structure Interaction (FSI) simulations. A relative error of 6.7% and 19.8% was obtained for peak systolic (WSSPS) and end diastolic (WSSED) WSS in the straight phantom, while in the stenotic phantom, a good similarity was found between measured and simulated WSS distribution, with a correlation coefficient, R, of 0.89 and 0.85 for WSSPS and WSSED, respectively. Moreover, the feasibility of the technique to detect pre-clinical atherosclerosis was tested in an atherosclerotic swine model. Six swines were fed atherogenic diet, while their left carotid artery was ligated in order to disturb flow patterns. Ligated arterial segments that were exposed to low WSSPS and WSS characterized by high frequency oscillations at baseline, developed either moderately or highly stenotic plaques (p < 0.05). Finally, feasibility of the technique was demonstrated in normal and atherosclerotic human subjects. Atherosclerotic carotid arteries with low stenosis had lower WSSPS as compared to control subjects (p < 0.01), while in one subject with high stenosis, elevated WSS was found on an arterial segment, which coincided with plaque rupture site, as determined through histological examination.

Cortical Thinning in High-Grade Asymptomatic Carotid Stenosis

BACKGROUND AND PURPOSE

High-grade carotid artery stenosis may alter hemodynamics in the ipsilateral hemisphere, but consequences of this effect are poorly understood. Cortical thinning is associated with cognitive impairment in dementia, head trauma, demyelination, and stroke. We hypothesized that hemodynamic impairment, as represented by a relative time-to-peak (TTP) delay on MRI in the hemisphere ipsilateral to the stenosis, would be associated with relative cortical thinning in that hemisphere.

METHODS

We used baseline MRI data from the NINDS-funded Carotid Revascularization and Medical Management for Asymptomatic Carotid Stenosis-Hemodynamics (CREST-H) study. Dynamic contrast susceptibility MR perfusion-weighted images were post-processed with quantitative perfusion maps using deconvolution of tissue and arterial signals. The protocol derived a hemispheric TTP delay, calculated by subtraction of voxel values in the hemisphere ipsilateral minus those contralateral to the stenosis.

RESULTS

Among 110 consecutive patients enrolled in CREST-H to date, 45 (41%) had TTP delay of at least 0.5 seconds and 9 (8.3%) subjects had TTP delay of at least 2.0 seconds, the maximum delay measured. For every 0.25-second increase in TTP delay above 0.5 seconds, there was a 0.006-mm (6 micron) increase in cortical thickness asymmetry. Across the range of hemodynamic impairment, TTP delay independently predicted relative cortical thinning on the side of stenosis, adjusting for age, sex, hypertension, hemisphere, smoking history, low-density lipoprotein cholesterol, and preexisting infarction (P=0.032).

CONCLUSIONS

Our findings suggest that hemodynamic impairment from high-grade asymptomatic carotid stenosis may structurally alter the cortex supplied by the stenotic carotid artery.

Allostatic load predicts racial disparities in intracerebral hemorrhage cognitive outcomes

A large portion of stroke disparities remains unexplained, even after adjusting for demographic, comorbidity, and health care access variables. There is a critical need to close this knowledge gap by investigating novel factors that may contribute to stroke disparities. Allostatic load (AL) is the lifetime adverse physiologic impact of needing to adjust to socially structured stressors such as racism. AL has been shown to increase health vulnerability and worsen outcomes in marginalized populations. We sought to assess the differential impact of AL on cognitive outcomes post intracerebral hemorrhage (ICH) across race-ethnicity. The Intracerebral Hemorrhage Outcomes Project (ICHOP) prospectively collected data from patients presenting to Columbia Medical Center with ICH from 3/2009 to 5/2016. Data included demographics, stroke scores, labs, complications, neuroimaging, medical history, and discharge data. Five markers of AL (HbA1c, WBC, SBP, HR, ALB) were obtained. An AL score was generated by summing the elements in each patient that fell outside normal ranges, with AL score ranging 0–5. A linear regression model, adjusted for stroke severity and ICH volumes, was used to evaluate the relationship between AL and Modified Telephone Interview for Cognitive Status (TICS-m) at discharge, stratified by race-ethnicity. Among 248 white, 195 black, and 261 Hispanic ICH patients, neither mean AL nor mean TICS differed by race/ethnicity (p = 0.51, p = 0.79 respectively). In the overall cohort AL did not predict TICS at discharge (Beta -1.0, SE 1.1, p = 0.353). In Whites (beta 1.18, SE 2.5, p = 0.646) and Hispanics (beta -0.95, SE 1.6, p = 0.552) AL was not associated with TICS at discharge. In Black patients, higher AL was associated with a decrease in TICS at discharge (beta -3.2, SE 1.5, p = 0.049). AL is an important determinant of post ICH outcomes for certain minority populations. AL may explain some of the unexplained health disparities in stroke populations.

TASC (Telehealth After Stroke Care): a study protocol for a randomized controlled feasibility trial of telehealth-enabled multidisciplinary stroke care in an underserved urban setting

Background

Hypertension is the most important modifiable risk factor for recurrent stroke, and blood pressure (BP) reduction is associated with decreased risk of stroke recurrence. However, hypertension remains poorly controlled in many stroke survivors. Black and Hispanic patients have a higher prevalence of uncontrolled BP and higher rates of stroke. Limited access to care contributes to challenges in post-stroke care. Telehealth After Stroke Care (TASC) is a telehealth intervention that integrates remote BP monitoring (RBPM) including nursing telephone support, tailored BP infographics and telehealth video visits with a multidisciplinary team approach including pharmacy to improve post-stroke care and reduce stroke disparities.

Methods

In this pilot trial, 50 acute stroke patients with hypertension will be screened for inclusion prior to hospital discharge and randomized to usual care or TASC. Usual care patients will be seen by a primary care nurse practitioner at 1–2 weeks and a stroke neurologist at 1 and 3 months. In addition to these usual care visits, TASC intervention patients will see a pharmacist at 4 and 8 weeks and will be enrolled in RBPM consisting of home BP monitoring with interval calls by a centralized team of telehealth nurses. As part of RBPM, TASC patients will be provided with a home BP monitoring device and electronic tablet that wirelessly transmits home BP data to the electronic health record. They will also receive tailored BP infographics that help explain their BP readings. The primary outcome will be feasibility including recruitment, adherence to at least one video visit and retention rates. The clinical outcome for consideration in a subsequent trial will be within-patient change in BP from baseline to 3 months after discharge. Secondary outcomes will be medication adherence self-efficacy and satisfaction with post-stroke telehealth, both measured at 3 months. Additional patient reported outcomes will include depression, cognitive function, and socioeconomic determinants. Multidisciplinary team competency and fidelity measures will also be assessed.

Conclusions

Integrated team-based interventions may improve BP control and reduce racial/ethnic disparities in post-stroke care. TASC is a post-acute stroke care model that is novel in providing RBPM with tailored infographics, and a multidisciplinary team approach including pharmacy. Our pilot will determine if such an approach is feasible and effective in enhancing post-stroke BP control and promoting self-efficacy.

Trial registration

ClinicalTrials.gov NCT04640519

Supplementary Information

The online version contains supplementary material available at 10.1186/s40814-022-01025-z.

Abstract WP202: Comorbidities, But Not Mechanism, Are Associated With Long-term Mortality After Stroke

Introduction: Stroke is one of the leading causes of death worldwide. Our study aimed to investigate clinical variables that influence long-term mortality.

Methods: A retrospective study was done in patients admitted with stroke to Columbia University Irving Medical Center - New York Presbyterian Hospital between 1990 and 2020 from whom data adjudication and long-term outcome were available at the time of analyses. Stroke was classified as cardioembolic, large vessel, small vessel and cryptogenic. We established 5 models which were progressively adjusted for cardiovascular risk factors and treatment modalities. Data was analyzed using cox proportional regression analysis to obtain hazard ratios (HR) with 95% confidence intervals (CI).

Results: The study included 775 patients with a mean age of 67±16 years; 47% were men, 32% had diabetes, 39% had dyslipidemia and 22% had a history of atrial fibrillation (AF). On discharge, 84% received statin therapy. After 8.9±5.9 years (0-17 years) of follow-up, 257 (33.2%) of the initial cohort died. In univariate analysis, stroke due to AF was the only predictor of long-term mortality compared to other mechanisms (HR 1.9, 95% CI 1.5-2.3), but the effect size and statistical significance were progressively attenuated after adjusting for confounders (HR 1.2, 95% CI 0.9-1.6). In the fully adjusted model, statin therapy on discharge (HR 0.6, 95% CI 0.5-0.9) was associated with decreased long-term mortality whereas higher NIHSS score on admission, older age and a history of diabetes were associated with higher long-term mortality (Table 1).

Conclusion: Comorbidities, and not stroke mechanism per se, are determinants of long-term mortality after stroke. Advanced age, diabetes mellitus, high NIHSS score are associated with higher long-term mortality whereas statin prescription upon discharge is associated with lower mortality. Post-stroke care strategies need to be targeted to reduce the risk of mortality in high-risk patients.

Abstract WP189: Ethnic And Racial Disparities In Prevalent Stroke Among Patients With Heart Failure

Background: Ethnic and racial disparities in healthcare contribute to cardiovascular morbidity and mortality. Stroke is prevalent among patients with heart failure (HF) and is associated with worse long-term outcomes. We hypothesized that disparities in cardiovascular risk profiles contribute to differences in stroke prevalence among patients with HF.

Methods: We performed a cross-sectional analysis of study participants age ≥ 60 in the biannual NHANES survey. Medical history and clinical variables were obtained from cycles 1999, 2001, 2011, and 2013. We created survey-weighted regression models to generate nationally representative estimates.

Results: A total of 20,315 study participants representing 212,156,242 adults were included, 2.5% with prevalent HF. Compared to those without HF, participants with HF were more often of White race (72.8% vs 68.3%, P = 0.02) and less often of Hispanic ethnicity (10.4% vs 14.3%, P = 0.04). Stroke was 10 times more prevalent among individuals with HF (20% vs 2%, P <0.001). In the general population, after controlling for risk factors, Black race was associated with higher risk of stroke (OR: 1.44; 95% CI: 1.16-1.78). There was a significant interaction between HF and race/ethnicity on prevalent stroke (P = 0.05) such that the odds of stroke with HF was significantly higher in individuals of Hispanic ethnicity (OR: 11.9; 95% CI: 4.94-28.6), but similar in White and Black participants. In the assessment of differential risk factor burden among individuals with HF, only rates of diabetes differed between Hispanic and White individuals (36.2% vs 25.5%, p=0.04). There was no difference in mean values of LDL, BMI, systolic blood pressures or prevalent smoking.

Conclusion: People of Hispanic ethnicity with HF have a higher prevalence of stroke which is not explained by vascular risk profiles and warrants further investigation.

Abstract WMP41: Heart Failure, Age And Functional Outcomes After Ischemic Stroke

Background: The presence of cardiovascular risk factors and associated diseases, including heart failure (HF), has been associated with worse outcomes following stroke. It is unclear however whether the association between HF and poor outcomes persists in younger cohorts, in whom HF is less often a consequence of long-standing cardiovascular disease. We hypothesize prevalent heart failure has differential associations with post-stroke functional outcomes across age groups.

Methods: We performed a retrospective analysis of patients admitted with acute ischemic stroke at Columbia University Medical Center between 1990-2020 for whom adjudicated data was available at the time of analyses. Demographic, clinical variables including NIHSS and TPA administration, and functional outcomes were extracted. Good functional outcome was defined as a discharge modified Rankin score ≤ 2. Multivariable regression models were used to determine adjusted odds ratios (aORs) and 95% confidence intervals (95% CI).

Results: Of the 855 patients hospitalized with ischemic stroke, 47% were women, 32% were ≤ 60 years, and 139 (16%) had pre-existing heart failure. Good functional outcome was seen in 456 (53%), in patients who had a mean age of 67.2 (16.4) years. Age as a continuous measure modified the effect of prevalent heart failure on the odds of good functional outcome (P = 0.001 for interaction). Among patients ≤ 60 years, after controlling for cardiovascular risk factors, NIHSS and TPA use, prevalent heart failure was associated with greater odds of good functional outcome (aOR: 1.33, 95% CI: 1.08-13.14) compared to young adults without HF. Among older stroke patients, HF was non-significantly associated with lower odds of good functional outcome (aOR: 0.86, 95% CI: 0.50-1.50).

Conclusion: Premature heart failure (often due to congenital defects, hereditary cardiomyopathies, infections or other non-vascular etiologies) in younger stroke patients may be a marker of lower cardiovascular disease burden compared to young adults with stroke secondary to traditional stroke risk factors. These factors may play a larger role in post-stroke outcomes and recovery.

Baseline Cognitive Impairment in Patients With Asymptomatic Carotid Stenosis in the CREST-2 Trial

BACKGROUND AND PURPOSE

Studies of carotid artery disease have suggested that high-grade stenosis can affect cognition, even without stroke. The presence and degree of cognitive impairment in such patients have not been reported and compared with a demographically matched population-based cohort.

METHODS

We studied cognition in 1000 consecutive CREST-2 (Carotid Revascularization and Medical Management for Asymptomatic Carotid Stenosis Trial) patients, a treatment trial for asymptomatic carotid disease. Cognitive assessment was after randomization but before assigned treatment. The cognitive battery was developed in the general population REGARDS Study (Reasons for Geographic and Racial Differences in Stroke), involving Word List Learning Sum, Word List Recall, and Word List fluency for animal names and the letter F. The carotid stenosis patients were >45 years old with ≥70% asymptomatic carotid stenosis and no history of prevalent stroke. The distribution of cognitive performance for the patients was standardized, accounting for age, race, and education using performance from REGARDS, and after further adjustment for hypertension, diabetes, dyslipidemia, and smoking. Using the Wald Test, we tabulated the proportion of Z scores less than the anticipated deviate for the population-based cohort for representative percentiles.

RESULTS

There were 786 baseline assessments. Mean age was 70 years, 58% men, and 52% right-sided stenosis. The overall Z score for patients was significantly below expected for higher percentiles (P<0.0001 for 50th, 75th, and 95th percentiles) and marginally below expected for the 25th percentile (P=0.015). Lower performance was attributed largely to Word List Recall (P<0.0001 for all percentiles) and for Word List Learning (50th, 75th, and 95th percentiles below expected, P≤0.01). The scores for left versus right carotid disease were similar.

CONCLUSIONS

Baseline cognition of patients with severe carotid stenosis showed below normal cognition compared to the population-based cohort, controlling for demographic and cardiovascular risk factors. This cohort represents the largest group to date to demonstrate that poorer cognition, especially memory, in this disease.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02089217.

Abstract P876: Allostatic Load Predicts Racial Disparities in Intracerebral Hemorrhage Outcomes

Introduction: A large portion of stroke disparities remains unexplained, even after controlling for an array of demographic, comorbidity, and health care access variables. There is a need to close this knowledge gap by investigating novel factors that may contribute to stroke disparities. Allostatic load (AL) is the lifetime adverse physiologic impact of needing to adjust to socially structured stressors such as racism. AL has been shown to increase health vulnerability and worsen outcomes in marginalized populations. We sought to assess the differential impact of AL on cognitive outcomes post intracerebral hemorrhage (ICH) across race-ethnicity.

Methods: The Columbia University Intracerebral Hemorrhage Outcomes Project (ICHOP) prospectively collected data from patients presenting to Columbia University Medical Center with a diagnosis of ICH from March 2009 to May 2016. Data included demographics, stroke scores, labs, neurological deterioration, hospital complications, neuroimaging, medical history, and discharge data. Ten markers of AL (BMI, A1c, SBP, triglycerides, CRP, HDL, LDL, HGB, HR, albumin) were obtained. An AL score was generated by summing the elements in each patient that fell outside normal clinical ranges, with an AL score range from 0-10. We used linear regression models to evaluate the relationship between AL and Telephone Interview for Cognitive Status (TICS) at discharge in the entire population, and then stratified by race-ethnicity.

Results: Among 248 White, 195 Black, and 261 Hispanic ICH patients, neither mean AL nor mean TICS differed by race/ethnicity (p=0.55, p=0.21 respectively). In the overall ICHOP cohort AL was associated with TICS at discharge (Beta -0.939, SE 0.46, p=0.043). In Whites and Hispanics AL was not associated with TICS at discharge (beta 0.267, SE 0.75, p=0.725, beta -0.71, SE 0.73, p=0.33 respectively). In Black patients, higher AL was associated with a decrease in TICS at discharge (beta -2.24, SE 0.90, p=0.016).

Conclusion: AL was associated with cognitive scores at discharge for Black patients but not Hispanics or Whites, suggesting that AL is an important determinant of post ICH outcomes for certain minority populations. AL may explain some of the unexplained health disparities in stroke populations.

Cardiovascular and cerebrovascular health after pre-eclampsia: the Motherhealth prospective cohort study protocol

INTRODUCTION

Cardiovascular and cerebrovascular diseases (CCVDs) are the leading cause of maternal mortality in the first year after delivery. Women whose pregnancies were complicated by pre-eclampsia are at particularly high risk for adverse events. In addition, women with a history of pre-eclampsia have higher risk of CCVD later in life. The physiological mechanisms that contribute to increased CCVD risk in these women are not well understood, and the optimal clinical pathways for postpartum CCVD risk reduction are not yet defined.

METHODS AND ANALYSIS

The Motherhealth Study (MHS) is a prospective cohort study at Columbia University Irving Medical Center (CUIMC), a quaternary care academic medical centre serving a multiethnic population in New York City. MHS began recruitment on 28 September 2018 and will enrol 60 women diagnosed with pre-eclampsia with severe features in the antepartum or postpartum period, and 40 normotensive pregnant women as a comparison cohort. Clinical data, biospecimens and measures of vascular function will be collected from all participants at the time of enrolment. Women in the pre-eclampsia group will complete an additional three postpartum study visits over 12-24 months. Visits will include additional detailed cardiovascular and cerebrovascular phenotyping. As this is an exploratory, observational pilot study, only descriptive statistics are planned. Data will be used to inform power calculations for future planned interventional studies.

ETHICS AND DISSEMINATION

The CUIMC Institutional Review Board approved this study prior to initiation of recruitment. All participants signed informed consent prior to enrolment. Results will be disseminated to the clinical and research community, along with the public, on completion of analyses. Data will be shared on reasonable request.

Decline in stroke alerts and hospitalisations during the COVID-19 pandemic

INTRODUCTION

Patients with stroke-like symptoms may be underutilising emergency medical services and avoiding hospitalisation during the COVID-19 pandemic. We investigated a decline in admissions for stroke and transient ischaemic attack (TIA) and emergency department (ED) stroke alert activations.

METHODS

We retrospectively compiled total weekly hospital admissions for stroke and TIA between 31 December 2018 and 21 April 2019 versus 30 December 2019 and 19 April 2020 at five US tertiary academic comprehensive stroke centres in cities with early COVID-19 outbreaks in Boston, New York City, Providence and Seattle. We collected available data on ED stroke alerts, stroke severity using the National Institutes of Health Stroke Scale (NIHSS) and time from symptom onset to hospital arrival.

RESULTS

Compared with 31 December 2018 to 21 April 2019, a decline in stroke/TIA admissions and ED stroke alerts occurred during 30 December 2019 to 19 April 2020 (p trend <0.001 for each). The declines coincided with state stay-at-home recommendations in late March. The greatest decline in hospital admissions was observed between 23 March and 19 April 2020, with a 31% decline compared with the corresponding weeks in 2019. Three of the five centres with 2019 and 2020 stroke alert data had a 46% decline in ED stroke alerts in late March and April 2020, compared with 2019. Median baseline NIHSS during these 4 weeks was 10 in 2020 and 7 in 2019. There was no difference in time from symptom onset to hospital arrival.

CONCLUSION

At these five large academic US hospitals, admissions for stroke and TIA declined during the COVID-19 pandemic. There was a trend for fewer ED stroke alerts at three of the five centres with available 2019 and 2020 data. Acute stroke therapies are time-sensitive, so decreased healthcare access or utilisation may lead to more disabling or fatal strokes, or more severe non-neurological complications related to stroke. Our findings underscore the indirect effects of this pandemic. Public health officials, hospital systems and healthcare providers must continue to encourage patients with stroke to seek acute care during this crisis.

Laser-induced fluorescence measurement of very slow neutral flows in a dusty plasma experiment

Laser-Induced Fluorescence (LIF) provides the temperature and flow velocity of a target species by direct measurement of its velocity distribution via Doppler shift. A LIF diagnostic has been developed at the Caltech water-ice dusty plasma experiment that uses an ultra-narrow tunable diode laser to pump the λ_vac = 696.735 nm argon neutral transition. A photomultiplier detects fluorescence emission at λ_vac = 772.633 nm. Signal to noise ratios in excess of 100 are achieved along with a high degree of reproducibility between measurements. A Labview program fully automates data collection throughout the three-dimensional plasma volume by controlling four stepper motors and recording measured data. The argon neutral temperature is measured to be slightly above room temperature. Challenges such as the lack of absolute calibration of diode lasers and wavelength drift due to slight changes in ambient room conditions are overcome to measure bulk neutral flow speeds on the order of 1-2 m/s with resolution on the order of 2/3 of a meter per second. High-speed video shows that introducing an argon flow to a cloud of ice grains causes the cloud of ice grains to move and change shape. Ice grain motion is analyzed and found to be in agreement with neutral LIF flow measurements. Surprisingly, when the flow ceases, the ice grain cloud reverts to its original location and shape.

Cognitive Impairment Correlates Linearly with Mean Flow Velocity by Transcranial Doppler below a Definable Threshold

INTRODUCTION

Low cerebral blood flow can affect cognition in patients with high-grade asymptomatic internal carotid artery stenosis. Current clinical algorithms use stroke risk to determine which patients should undergo revascularization without considering cognitive decline. Although correlations between low-flow and cognitive impairment have been reported, it is not known whether a threshold exists below which such a correlation expresses itself. Such information would be critical in treatment decisions about whether to intervene in patients with high-grade carotid artery stenosis who are at risk for cognitive decline.

OBJECTIVE

To determine how reduced blood flow correlates with lower cognitive scores.

METHODS

Patients with ≥80% unilateral internal carotid artery stenosis with no history of stroke were recruited from inpatient and outpatient practices at a single, large, comprehensive stroke center. Patients underwent bilateral insonation of middle cerebral arteries with standard 2-Hz probes over the temporal windows with transcranial Doppler. Cognitive assessments were performed by an experienced neuropsychologist using a cognitive battery comprising 14 standardized tests with normative samples grouped by age. Z-scores were generated for each test and averaged to obtain a composite Z-score for each patient. Multivariable linear regression examined associations between mean flow velocity (MFV) and composite Z-score, adjusting for age, education, and depression. The Davies test was used to determine if there was a breakpoint for a non-zero difference in slope of a segmented relationship over the range of composite Z-score values.

RESULTS

Forty-two patients with unilateral high-grade internal carotid artery stenosis without stroke were enrolled (26 males, age = 74 ± 9 years, education = 16 ± 3 years). Average composite Z-score was -0.31 SD below the age-specific normative mean (range -2.8 to +1.2 SD). In linear regression adjusted for age, education, and depression, MFV correlated with cognitive Z-score (β = 0.308, p = 0.043). A single breakpoint in the range of composite Z-scores was identified at 45 cm/s. For MFV <45 cm/s, Z-score decreased 0.05 SD per cm/s MFV (95% CI: 0.01-0.10). For MFV >45 cm/s, Z-score change was nonsignificant (95% CI: -0.07 to 0.05).

CONCLUSIONS

In high-grade, asymptomatic carotid artery stenosis, cognitive impairment correlated linearly with lower flow in the hemisphere fed by the occluded internal carotid artery, but only below a threshold of MFV = 45 cm/s. Identifying a hemodynamic threshold for cognitive decline using a simple, noninvasive method may influence revascularization decision-making in otherwise "asymptomatic" carotid disease.

Poststroke Montreal Cognitive Assessment and Recurrent Stroke in Patients With Symptomatic Intracranial Atherosclerosis

BACKGROUND AND PURPOSE

Cognitive impairment occurs in 20%-40% of stroke patients and is a predictor of long-term morbidity and mortality. In this study, we aim to determine the association between poststroke cognitive impairment and stroke recurrence risk, in patients with anterior versus posterior circulation intracranial stenosis.

METHODS

This is a post-hoc analysis of the Stenting and Aggressive Medical Therapy for Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS) trial. The primary predictor was poststroke cognitive function measured by Montreal Cognitive Assessment (MOCA) at 3-6 months and the primary outcome was recurrent ischemic stroke. We used univariate and multivariable cox-regression models to determine the associations between MOCA at 3-6 months and recurrent stroke.

RESULTS

Of the 451 patients enrolled in SAMMPRIS, 393 patients met the inclusion criteria. The mean age of the sample (in years) was 59.5 ± 11.3, 62.6% (246 of 393) were men. Fifty patients (12.7%) had recurrent ischemic stroke during a mean follow up of 2.7 years. The 3-6 month MOCA score was performed on 351 patients. In prespecified multivariable models, there was an association between 3 and 6 month MOCA and recurrent stroke (hazard ratio [HR] per point increase .93 95% confidence interval [CI] .88-.99, P = .040). This effect was present in anterior circulation stenosis (adjusted HR per point increase .92 95% CI .85-0.99, P = .022) but not in posterior circulation artery stenosis (adjusted HR per point increase 1.00 95% .86-1.16, P = .983).

CONCLUSIONS

Overall, we found weak associations and trends between MoCA at 3-6 months and stroke recurrence but more notable and stronger associations in certain subgroups. Since our study is underpowered, larger studies are needed to validate our findings and determine the mechanism(s) behind this association.

Joint time-frequency analysis of dynamic cerebral autoregulation using generalized harmonic wavelets

OBJECTIVE

To develop a joint time-frequency analysis technique based on generalized harmonic wavelets (GHWs) for dynamic cerebral autoregulation (DCA) performance quantification.

APPROACH

We considered two groups of human subjects to develop and validate the method: 55 healthy volunteers and 35 stroke-free subjects with unilateral internal carotid artery stenosis (CAS). We determined the mean and coherence-weighted average of the phase shift (PS) of appropriately defined GHW-based transfer functions, based on data points over the joint time-frequency domain. We compared agreement of standard transfer function analysis (TFA) and GHW analyses in healthy subjects using Bland-Altman plots. We assessed sensitivity of each metric to detect the presumed side-to-side difference in DCA function in CAS subjects (with decreased PS on the occluded side), using McNemar's chi square test to compare each metric to the standard TFA approach. An alternative Morlet wavelet-based approach was also considered.

MAIN RESULTS

The GHW and TFA methods exhibited strong agreement in healthy subjects. Among CAS subjects, GHW metrics outperformed TFA and Morlet wavelet-based approaches in identifying expected side-to-side differences: TFA sensitivity was 40.0% (95%CI 23.9-57.9), Morlet 60.0% (95%CI 42.1-76.1), and GHW  >70% for both metrics (GHW mean PS sensitivity 74.3, 95%CI 56.7-87.5, p   =  0.0027 versus TFA; GHW coherence-weighted PS sensitivity 71.4, 95%CI 53.7-85.4, p   =  0.0009 versus TFA).

SIGNIFICANCE

In comparison to the widely used stationary Fourier transform-based TFA and to Morlet wavelet-based analysis, our data suggest that the GHW-based analysis performs better in identifying DCA asymmetry between the two cerebral hemispheres in patients with high grade unilateral carotid stenosis. Our method may provide enhanced confidence in employing DCA metrics as a sensitive diagnostic tool for detecting impaired DCA function in a variety of pathological settings.

Spatial coefficient of variation of arterial spin labeling MRI as a cerebrovascular correlate of carotid occlusive disease

Clinical interpretation of arterial spin labeling (ASL) perfusion MRI in cerebrovascular disease remains challenging mainly because of the method's sensitivity to concomitant contributions from both intravascular and tissue compartments. While acquisition of multi-delay images can differentiate between the two contributions, the prolonged acquisition is prone to artifacts and not practical for clinical applications. Here, the utility of the spatial coefficient of variation (sCoV) of a single-delay ASL image as a marker of the intravascular contribution was evaluated by testing the hypothesis that sCoV can detect the effects of differences in label arrival times between ipsi- and contra-lateral hemispheres even in the absence of a hemispheric difference in CBF. Hemispheric lateralization values for sCoV and CBF were computed from ASL images acquired on 28 patients (age 73.9 ± 10.2 years, 8 women) with asymptomatic unilateral carotid occlusion. The results showed that sCoV lateralization predicted the occluded side with 96.4% sensitivity, missing only 1 patient. In contrast, the sensitivity of the CBF lateralization was 71.4%, with 8 patients showing no difference in CBF between hemispheres. The findings demonstrate the potential clinical utility of sCoV as a cerebrovascular correlate of large vessel disease. Using sCoV in tandem with CBF, vascular information can be obtained in image processing without the need for additional scan-time.

Abstract TP483: Transcatheter Aortic Valve Replacement (TAVR) Does Not Improve Cerebral Hemodynamics or Neurocognition in Patients With Severe Aortic Stenosis

Objective: To determine if aortic stenosis (AS) is associated with altered cerebral hemodynamics and impaired neurocognition, and whether TAVR improves hemodynamics and cognition.

Background: AS results in higher systolic pressure to overcome resistance from the stenotic valve, leading to heart failure and decline in cardiac output. There has been no baseline assessment of CBF with neurocognition in AS, or the effects of valve replacement.

Methods: In 40 patients with planned TAVR, transcranial Doppler (TCD) assessed bilateral MCA mean flow velocity (MFV); abnormality was < 30cc/sec. The neurocognitive battery assessed memory, language, attention, visual-spatial skills, and executive function, yielding an average Z-score. Impairment was < 1.5 SD’s below the normative mean.

Results: The mean age was 78 years, 59% male, and the mean valve gradient was 46.87%. Mean follow-up was 36 days post-TAVR (range 27 - 55). Before TAVR, the average MFV was 42 cc/sec (SD=10.22), and the mean cognitive score was -0.22 SD’s (range -1.99 to 1.08) below the normative mean. Of the 5 with abnormal MFV’s, none had abnormal cognition (average=0.19 SD’s above the normative mean). After TAVR, the MFV was 43 cc/sec, not different from baseline (p=0.56). The post-TAVR average Z-score was 0.01 SD’s above the normative mean, also not different from baseline (p=0.29). There was no correlation between the change scores in MFV and in neurocognition (r = 0.08, p= 0.69).

Conclusions: Among patients with severe AS, there was no correlation at baseline between abnormal MFV’s on TCD and abnormal neurocognition. It was therefore unsurprising that there was little impact of valve replacement on these measures of cerebral blood flow and brain function. Prior assumptions about diminished CBF and the relationship to cognitive function may not be supported.

Abstract TP141: Can the Human Eye Match a Computer Algorithm in Identifying Hypoperfusion in Asymptomatic Carotid Artery Stenosis?

Background: Perfusion weighted imaging on MRI (MRP) and computerized tomography perfusion (CTP) are increasingly required to manage large vessel disease. Computerized algorithms can quantify perfusion data, but the programs are expensive and not widely used outside acute stroke evaluation. We aimed to determine how well human observers can identify asymmetries in cerebral perfusion images compared with an automated computer algorithm.

Methods: Ten clinicians experienced in treating carotid artery disease (4 vascular neurologists, 3 neuroradiologists, 1 vascular surgeon, 1 neurosurgeon, 1 interventional radiologist) were given 28 post-processed, color-coded, axial-slice MRP scans from patients in the Carotid Revascularization Endovascular versus Stenting Trial - Hemodynamics (CREST-H) study. All patients had >70%, unilateral, asymptomatic carotid artery stenosis and had varying degrees of time-to-peak (TTP) delay on the side of stenosis, ranging from 0 to 2 secs, quantified by a semi-automated system that computes quantitative perfusion maps, using deconvolution of tissue and arterial signals (Olea, Cambridge, MA). A minimum volume of 10cc was required for a given TTP delay. Clinicians were asked to determine asymmetry (y/n) and side of occlusion for each case. Number of correct responses that matched the computer output were tallied.

Results: We averaged correct responses by the 10 clinicians for cases at each increment of TTP delay; (Figure). At TTP delays ≥1.5 seconds, accuracy was ≥80%. At 1.25 sec accuracy fell to 60%, and at ≤ 1 sec, accuracy was ≤50%. For TTP=0 (no asymmetry), accuracy was 71%.

Conclusions: Visual impression of hemodynamic asymmetry among experienced clinicians was reasonably accurate for TTP delays ≥1.5 seconds, but declined with more subtle asymmetries. Depending on the clinical impact of TTP delays (for CREST-H: correlation with cognitive decline), experienced clinicians may perform as well as an automated algorithm.

Changes on Dynamic Cerebral Autoregulation Are Associated with Delayed Cerebral Ischemia in Patients with Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

Early identification of vasospasm prior to symptom onset would allow prevention of delayed cerebral ischemia (DCI) in aneurysmal subarachnoid hemorrhage (aSAH). Dynamic cerebral autoregulation (DCA) is a noninvasive means of assessing cerebral blood flow regulation by determining independence of low-frequency temporal oscillations of systemic blood pressure (BP) and cerebral blood flow velocities (CBFV).

METHODS

Eight SAH patients underwent prospectively a median of 7 DCA assessments consisting of continuous measurements of BCFV and BP. Transfer function analysis was applied to calculate average phase shift (PS) in low (0.07-0.2 Hz) frequency range for each hemisphere as continuous measure of DCA. Lower PS indicated poorer regulatory response. DCI was defined as a 2-point decrease in Glasgow Coma Score and/or infarction on CT.

RESULTS

Three subjects developed symptomatic vasospasm with median time-to-DCI of 9 days. DCI was significantly associated with lower PS over the entire recording period (Wald = 4.28; p = 0.039). Additionally, there was a significant change in PS over different recording periods after adjusting for DCI (Wald = 15.66; p = 0.001); particularly, a significantly lower mean PS day 3-5 after bleed (14.22 vs 27.51; p = 0.05).

CONCLUSIONS

DCA might be useful for early detection of symptomatic vasospasm. A larger cohort study of SAH patients is currently underway.

A Multilevel Analysis of Surgical Category and Individual Patient-Level Risk Factors for Postoperative Stroke

Background and Purpose

Many studies supporting the association between specific surgical procedure categories and postoperative stroke (POS) do not account for differences in patient-level characteristics between and within surgical categories. The risk of POS after high-risk procedure categories remains unknown after adjusting for such differences in patient-level characteristics.

Methods

Using inpatients in the American College of Surgeons National Surgical Quality Initiative Program database, we conducted a retrospective cohort study between January 1, 2000, and December 31, 2010. Our primary outcome was POS within 30 days of surgery. We characterized the relationship between surgical- and individual patient-level factors and POS by using multivariable, multilevel logistic regression that accounted for clustering of patient-level factors with surgical categories.

Results

We identified 729 886 patients, 2703 (0.3%) of whom developed POS. Dependent functional status (odds ratio [OR]: 4.11, 95% confidence interval [95% CI]: 3.60-4.69), history of stroke (OR: 2.35, 95%CI: 2.06-2.69) or transient ischemic attack (OR: 2.49 95%CI: 2.19-2.83), active smoking (OR: 1.20, 95%CI: 1.08-1.32), hypertension (OR: 2.11, 95%CI: 2.19-2.82), chronic obstructive pulmonary disease (OR: 1.39 95%CI: 1.21-1.59), and acute renal failure (OR: 2.35, 95%CI: 1.85-2.99) were significantly associated with POS. After adjusting for clustering, patients who underwent cardiac (OR: 11.25, 95%CI: 8.52-14.87), vascular (OR: 4.75, 95%CI: 3.88-5.82), neurological (OR: 4.60, 95%CI: 3.48-6.08), and general surgery (OR: 1.40, 95%CI: 1.15-1.70) had significantly greater odds of POS compared to patients undergoing other types of surgical procedures.

Conclusions

Vascular, cardiac, and neurological surgery remained strongly associated with POS in an analysis accounting for the association between patient-level factors and surgical categories.

National Institutes of Health StrokeNet Training Core

Background and Purpose- The National Institutes of Health (NIH) StrokeNet provides a nationwide infrastructure to advance stroke research. Capitalizing on this unique opportunity, the NIH StrokeNet Training Core (NSTC) was established with the overarching goal of enhancing the professional development of a diverse spectrum of professionals who are embedded in the stroke clinical trials network of the NIH StrokeNet. Methods- This special report provides a descriptive account of the rationale, organization, and activities of the NSTC since its inception in 2013. Current processes and their evolution over time for facilitating training of NIH StrokeNet trainees have been highlighted. Data collected for monitoring training are summarized. Outcomes data (publications and grants) collected by NSTC was supplemented by publicly available resources. Results- The NSTC comprises of cross-network faculty, trainees, and education coordinators. It helps in the development and monitoring of training programs and organizes educational and career development activities. Trainees are provided directed guidance towards their mandated research projects, including opportunities to present at the International Stroke Conference. The committee has focused on developing sustainable models of peer-to-peer interaction and cross-institutional mentorships. A total of 124 professionals (43.7% female, 10.5% underrepresented minorities) have completed training between 2013 and 2018, of whom 55% were clinical vascular neurologists. Of the total, 85% transitioned to a formal academic position and 95% were involved in stroke research post-training. Altogether, 1659 indexed publications have been authored or co-authored by NIH StrokeNet Trainees, of which 58% were published during or after their training years. Based on data from 109 trainees, 33% had submitted 72 grant proposals as principal or co-principal investigators of which 22.2% proposals have been funded. Conclusions- NSTC has provided a foundation to foster nationwide training in stroke research. Our data demonstrate strong contribution of trainees towards academic scholarship. Continued innovation in educational methodologies is required to adapt to unique training opportunities such as the NIH StrokeNet.

Geographic Analysis of Mobile Stroke Unit Treatment in a Dense Urban Area: The New York City METRONOME Registry

Background Mobile stroke units (MSUs) reduce time to intravenous thrombolysis in acute ischemic stroke. Whether this advantage exists in densely populated urban areas with many proximate hospitals is unclear. Methods and Results We evaluated patients from the METRONOME (Metropolitan New York Mobile Stroke) registry with suspected acute ischemic stroke who were transported by a bi-institutional MSU operating in Manhattan, New York, from October 2016 to September 2017. The comparison group included patients transported to our hospitals via conventional ambulance for acute ischemic stroke during the same hours of MSU operation (Monday to Friday, 9 am to 5 pm). Our exposure was MSU care, and our primary outcome was dispatch-to-thrombolysis time. We estimated mean differences in the primary outcome between both groups, adjusting for clinical, demographic, and geographic factors, including numbers of nearby designated stroke centers and population density. We identified 66 patients treated or transported by MSU and 19 patients transported by conventional ambulance. Patients receiving MSU care had significantly shorter dispatch-to-thrombolysis time than patients receiving conventional care (mean: 61.2 versus 91.6 minutes; P=0.001). Compared with patients receiving conventional care, patients receiving MSU care were significantly more likely to be picked up closer to a higher mean number of designated stroke centers in a 2.0-mile radius (4.8 versus 2.7, P=0.002). In multivariable analysis, MSU care was associated with a mean decrease in dispatch-to-thrombolysis time of 29.7 minutes (95% CI, 6.9-52.5) compared with conventional care. Conclusions In a densely populated urban area with a high number of intermediary stroke centers, MSU care was associated with substantially quicker time to thrombolysis compared with conventional ambulance care.

Cognition and Quality of Life in Symptomatic Carotid Occlusion

PURPOSE

Carotid occlusion may result in stroke, TIA, and cognitive reductions. Whether cognition predicts quality of life (QOL) for patients with carotid occlusion is unknown. Depression is also known to affect QOL. We examined whether cognition and depression predicted QOL in patients with carotid occlusive disease who have not had revascularization.

METHODS

Patients with unilateral carotid occlusion and history of TIA or a remote history of minor stroke were included. Patients underwent exam of memory, language, motor, and executive function skills and completed depression and QOL questionnaires (Center for Epidemiological Studies-Depression [CES-D], Stroke Specific QOL [SSQOL]). Deficits from remote stroke were assessed with the NIH Stroke Scale (NIHSS). Z-scores for cognitive tests were averaged (Cog-Z). The SSQOL scores were averaged across subgroup domains. Analyses of patients with all depression levels were followed by subgroup analyses for patients with minimal depression. Correlation findings were used to select the variables in a regression model to predict SSQOL.

RESULTS

Among 37 patients with all depression levels, QOL was predicted by deficits from remote stroke and depression (F(3, 36) = 21.15, P<.0005; NIHSS Beta = -.392, P = .001; CES-D Beta = -.577, P < .0005). Among 22 patients with minimal depression, QOL was predicted by cognitive and depression scores, (F(2,21) = 7.88, P = .003; Cog-Z Beta = .364, P = .05; CES-D Beta = -.495, P = .01).

CONCLUSIONS

In patients with carotid occlusive disease without major stroke and without revascularization, cognitive and depression scores independently predicted QOL. These data demonstrate the clinical relevance of cognitive and mood decline among patients with carotid occlusion.

Abstract WP104: Clinical Characteristics of Stroke Mimics Treated on an Urban Mobile Stroke Unit

Introduction: It is unknown how the clinical characteristics of stroke mimics treated on Mobile Stroke Units (MSUs) compare to confirmed acute strokes treated on these units.

Methods: We retrospectively analyzed all patients transported by the NewYork-Presbyterian MSU in New York City from October 2016-May 2018. A vascular neurologist assigned a final diagnosis after comprehensive medical record review. Clinical data were abstracted, including comorbidities, presenting symptoms, stroke severity, acute treatments, and short-term outcomes. We compared characteristics of patients with a stroke mimic diagnosis versus those with acute ischemic or hemorrhagic stroke using targeted minimum loss-based estimation to adjust for demographics, comorbidities, NIH Stroke Scale (NIHSS) score, and intravenous tPA administration.

Results: Among 92 suspected stroke patients transported by MSU, 56 (61%) had confirmed acute stroke (77% ischemic, 23% hemorrhagic) and 36 (39%) had a stroke mimic. Mimics consisted of seizure (n=8), metabolic encephalopathy (n=6), somatoform disorders (n=4), and others (n=18). The mean NIHSS score was 8 (SD 7) among mimics versus 11 (SD 8) among confirmed strokes (p=0.14). The top presenting symptoms among mimics were unilateral weakness (n=8), aphasia (n=6), confusion (n=6), and decreased consciousness (n=6). Nine mimics (25%) received tPA and none had hemorrhagic conversion; while 30 (53%) confirmed strokes received tPA and 2 (7%) had hemorrhagic conversion. There was no difference in MSU arrival-to-tPA time between groups (46 vs. 44 minutes, p=0.70). In multivariable analyses, compared to patients with confirmed stroke, mimics had significantly lower NIHSS scores, higher initial blood pressures, and shorter lengths-of-stay. Rates of death and discharge disposition were similar between groups.

Conclusions: Among patients transported by a MSU for suspected stroke, two-fifths were stroke mimics. Seizure, metabolic encephalopathy, and somatoform disorders were the most common mimic diagnoses. Patients with stroke mimics had lower NIHSS scores and less often were treated with tPA.

Abstract TP153: Cognitive Profile in Patients With Hemodynamic Failure Due to Severe Carotid Stenosis

Background: Severe carotid stenosis can reduce cognition due to hypoperfusion. Published cognitive profiles for vascular disease are variable, however, precluding identification of hemodynamic failure as a specific cause. We investigated the relationship among carotid stenosis, hemodynamic failure, and cognition by characterizing cognition in patients with severe carotid stenosis, with and without hemodynamic failure.

Methods: Sixty-one patients (18 with TIA, none with stroke) with ≥80% carotid stenosis were drawn from two study cohorts, RECON and BFC 1 . Hemodynamic status was assessed using oxygen extraction fraction by positron emission tomography (RECON) or mean flow velocity by transcranial Doppler (BFC) and dichotomized into normal (n=30) vs impaired (n=31). Cognition was assessed with 16 tests. Sixteen linear regressions, one for each cognitive test, were performed to assess the influence of hemodynamic failure on test scores, adjusting for side of occlusion, depression, age, gender, education, and study cohort. Multiple comparisons were adjusted using false discovery rate (FDR) correction.

Results: Hemodynamic failure was a significant independent predictor for Rey Complex Figure Test-Copy (RCFT-C, p=0.007), RCFT-Delayed Recall (RCFT-D, p=0.003), and Trail Making Test-B (TMT-B, p=0.006) and remained so after FDR correction. The other tests were not predicted by hemodynamic status.

Conclusions: Tests of mental flexibility, visuospatial skill, and organization were sensitive to hemodynamic failure in patients with severe carotid stenosis. A larger sample is required to validate this cognitive profile in such patients. Cognitive assessment with RCFT-C, RCFT-D, and TMT-B may detect the effects of hemodynamic failure specific to large vessel disease, having research and treatment utility. 1 NINDS NS048212 (Randomized Evaluation of Carotid Occlusion and Neurocognition -RECON), R01NS076277 (Blood Flow and Cognition - BFC)

Is Hemispheric Hypoperfusion a Treatable Cause of Cognitive Impairment?

PURPOSE OF REVIEW

To review the current literature that supports the notion that cerebral hemodynamic compromise from internal carotid artery stenosis may be a cause of vascular cognitive impairment that is amenable to treatment by revascularization.

RECENT FINDINGS

Converging evidence suggests that successful carotid endarterectomy and carotid artery stenting are associated with reversal of cognitive decline in many patients with severe but asymptomatic carotid artery stenosis. Most of these findings have been derived from cohort studies and comparisons with either normal or surgical controls. Failure to find treatment benefit in a number of studies appears to have been the result of patient heterogeneity or confounding from concomitant conditions independently associated with cognitive decline, such as heart failure and other cardiovascular risk factors, or failure to establish pre-procedure hemodynamic failure. Patients with severe carotid artery stenosis causing cerebral hemodynamic impairment may have a reversible cause of cognitive decline. None of the prior studies, however, were done in the context of a randomized clinical trial with large numbers of participants. The ongoing CREST-2 trial comparing revascularization with medical therapy versus medical therapy alone, and its associated CREST-H study determining whether cognitive decline is reversible among those with hemodynamic compromise may address this question.

Pathological correlates of brain arterial calcifications

BACKGROUND

In clinical practice, calcifications seen on computed tomographic studies within the large brain arteries are often referred to as a surrogate marker for cholesterol-mediated atherosclerosis. However, limited data exist to support the association between calcification and atherosclerosis. In this study, we examined if intracranial arterial calcifications were associated with cholesterol-mediated intracranial large artery atherosclerosis (ILAA) within the arteries of the circle of Willis in an autopsy-based sample.

METHODS

We carried out a cross-sectional analysis of histopathological characteristics of brain large arteries obtained from autopsy cases. Brain large arteries were examined for evidences of calcifications, which were rated as macroscopic (coalescent) and microscopic (scattered). In addition to calcification, we also obtained measurement of the arterial wall and the presence of ILAA and nonatherosclerotic arterial fibrosis. We built hierarchical models adjusted for demographic and vascular risk factors to assess the relationship between calcification and ILAA.

RESULTS

In univariate analysis, the presence of any arterial calcifications was associated with cerebral infarcts (29% vs. 14%, P<.01). Multivariate analysis revealed that among all calcifications, coalescent calcifications were not associated with ILAA. In contrast, scattered calcifications were associated with ILAA (P<.001), decreased lumen diameter (-1.87 +/- 0.41 mm, P≤.001), and increased luminal stenosis (0.03% +/- 0.01%, P≤.006). These findings were independent of age, sex, or other vascular risk factors.

CONCLUSIONS

This study demonstrates that coalescent calcifications in brain large arteries, although associated with morbidity, are not synonymous with cholesterol-driven ILAA. Understanding the precise pathological components of cerebrovascular disease, including nonatherosclerotic arterial calcifications, will help develop individualized therapies beyond amelioration of traditional risk factors such as hyperlipidemia.

Impact of Patient Language on Emergency Medical Service Use and Prenotification for Acute Ischemic Stroke

Background and Purpose

Use of emergency medical services (EMS) is associated with decreased door-to-needle time in acute ischemic stroke (AIS). Whether patient language affects EMS utilization and prenotification in AIS has been understudied. We sought to characterize EMS use and prenotification by patient language among intravenous tissue plasminogen activator (IV-tPA) tissue plasminogen (IV-tPA) treated patients at a single center with a large Spanish-speaking patient population.

Methods

We performed a retrospective analysis of all patients who received IV-tPA in our emergency department between July 2011 and June 2016. Baseline characteristics, EMS use, and prenotification were compared between English- and Spanish-speaking patients. Logistic regression was used to measure the association between patient language and EMS use.

Results

Of 391 patients who received IV-tPA, 208 (53%) primarily spoke English and 174 (45%) primarily spoke Spanish. Demographic and clinical factors including National Institutes of Health Stroke Scale (NIHSS) did not differ between language groups. Emergency medical services use was higher among Spanish-speaking patients (82% vs 70%; P < .01). Prenotification did not differ by language (61% vs 63%; P = .8). In a multivariable model adjusted for age, sex, and NIHSS, Spanish speakers remained more likely to use EMS (odds ratio: 1.8, 95% confidence interval: 1.1-3.0).

Conclusion

Emergency medical services usage was higher in Spanish speakers compared to English speakers among AIS patients treated with IV-tPA; however, prenotification rates did not differ. Future studies should evaluate differences in EMS utilization according to primary language and ethnicity.

Transcranial Doppler Waveforms During Intra-aortic Balloon Pump Counterpulsation for Vasospasm Detection After Subarachnoid Hemorrhage

BACKGROUND

Transcranial Doppler ultrasound is a standard screening tool for vasospasm after subarachnoid hemorrhage. Prevention of vasospasm-induced delayed cerebral ischemia after subarachnoid hemorrhage depends on optimization of cerebral perfusion pressure, which can be challenged by neurogenic stress cardiomyopathy. Intra-aortic balloon pumps have been utilized to augment cerebral perfusion, but they change the transcranial Doppler waveform, altering its interpretability for vasospasm screening.

OBJECTIVE

To assess the features of the transcranial Doppler waveform that correlate with vasospasm.

METHODS

We retrospectively reviewed cases of subarachnoid hemorrhage that underwent same-day transcranial Doppler ultrasound and angiography. Transcranial Doppler waveforms were assessed for mean velocity, peak systolic velocity, balloon pump-augmented diastolic velocity, and a novel feature, "delta velocity" (balloon pump-augmented velocity - systolic velocity). Relationship of flow velocity features to vasospasm was estimated by generalized estimating equation models using a Gaussian distribution and an exchangeable correlation structure.

RESULTS

There were 31 transcranial Doppler and angiography pairings (12 CT angiography/19 digital subtraction angiography) from 4 patients. Fourteen pairings had proximal vasospasm by angiography. Delta velocity was associated with proximal vasospasm (coefficient -6.8 [95% CI -9.8 to -3.8], P < .001). There was no significant correlation with proximal vasospasm for mean velocity (coefficient -13.0 [95% CI -29.3 to 3.4], P = .12), systolic velocity (coefficient -8.7 [95% CI -24.8 to 7.3], P = .29), or balloon pump-augmented velocity (coefficient -15.3 [95% CI -31.3 to 0.71], P = .06).

CONCLUSION

Delta velocity, a novel transcranial Doppler flow velocity feature, may reflect vasospasm in patients with subarachnoid hemorrhage and intra-aortic balloon pumps.

Carotid revascularization and medical management for asymptomatic carotid stenosis - Hemodynamics (CREST-H): Study design and rationale

RATIONALE

For patients with asymptomatic high-grade carotid stenosis, clinical investigations have focused on preventing cerebral infarction, yet stenosis that reduces cerebral blood flow may independently impair cognition. Whether revascularization of a hemodynamically significant carotid stenosis can alter the course of cognitive decline has never been investigated in the context of a randomized clinical trial.

HYPOTHESIS

Among patients randomized in the Carotid Revascularization and Medical Management for Asymptomatic Carotid Stenosis (CREST-2) trials, the magnitude of treatment differences (revascularization versus medical management alone) with regard to cognition will differ between those with flow impairment compared to those without flow impairment.

SAMPLE SIZE

We will enroll approximately 500 patients from CREST-2, of which we anticipate 100 will have hemodynamic impairment. We estimate 93% power to detect a clinically meaningful treatment difference of 0.5 SD.

METHODS AND DESIGN

We will use perfusion-weighted magnetic resonance imaging to stratify by hemodynamic status. Linear regression will compare treatment differences, controlling for baseline cognitive status, age, depression, prior cerebral infarcts, silent infarction, white matter hyperintensity volume, and cerebral microbleeds.

STUDY OUTCOMES

The primary outcome is change in cognition at one year. Secondary outcomes include silent infarction, change in white matter hyperintensity volume, number of cerebral microbleeds, and cortical thickness over one year.

DISCUSSION

If cognitive impairment can be shown to be reversible by revascularization, then we can redefine "symptomatic carotid stenosis" to include cognitive impairment and identify a new population of patients likely to benefit from revascularization.

TRIAL REGISTRATION

US National Institutes of Health (NIH) clinicaltrials.gov NCT03121209.

Perfusion imaging and recurrent cerebrovascular events in intracranial atherosclerotic disease or carotid occlusion

Background

Large vessel disease stroke subtype carries the highest risk of early recurrent stroke. In this study we aim to look at the association between impaired perfusion and early stroke recurrence in patients with intracranial atherosclerotic disease or total cervical carotid occlusion.

Methods

This is a retrospective study from a comprehensive stroke center where we included consecutive patients 18 years or older with intracranial atherosclerotic disease or total cervical carotid occlusion admitted with a diagnosis of ischemic stroke within 24 h from symptom onset with National Institute Health Stroke Scale < 15, between 1 December 2016 and 30 June 2017. Patients with (1) evidence of ≥ 50% stenosis of a large intracranial artery or total carotid artery occlusion, (2) symptoms referable to the territory of the affected artery, and (3) perfusion imaging data using the RAPID processing software were included. The primary predictor was unfavorable perfusion imaging defined as Tmax > 6 s mismatch volume (penumbra volume–infarct volume) of 15 ml or more. The outcome was recurrent cerebrovascular events at 90 days defined as worsening or new neurological symptoms in the absence of a nonvascular cause attributable to the decline, or new infarct or infarct extension in the territory of the affected artery. We used Cox proportional hazards models to determine the association between impaired perfusion and recurrent cerebrovascular events.

Results

Sixty-two patients met our inclusion criteria; mean age 66.4 ± 13.1 years, 64.5% male (40/62) and 50.0% (31/62) with intracranial atherosclerotic disease. When compared to patients with favorable perfusion pattern, patients with unfavorable perfusion pattern were more likely to have recurrent cerebrovascular events (55.6% (10/18) versus 9.1% (4/44), p < 0.001). This association persisted after adjusting for potential confounders (adjusted hazard ratio 10.44, 95% confidence interval 2.30–47.42, p = 0.002).

Conclusion

Perfusion mismatch predicts recurrent cerebrovascular events in patients with ischemic stroke due to intracranial atherosclerotic disease or total cervical carotid occlusion. Studies are needed to determine the utility of revascularization strategies in this patient population.

Clinical Information Systems Integration in New York City's First Mobile Stroke Unit

BACKGROUND

Mobile stroke units (MSUs) reduce time to thrombolytic therapy in acute ischemic stroke. These units are widely used, but the clinical information systems underlying MSU operations are understudied.

OBJECTIVE

The first MSU on the East Coast of the United States was established at New York Presbyterian Hospital (NYP) in October 2016. We describe our program's 7-month pilot, focusing on the integration of our hospital's clinical information systems into our MSU to support patient care and research efforts.

METHODS

NYP's MSU was staffed by two paramedics, one radiology technologist, and a vascular neurologist. The unit was equipped with four laptop computers and networking infrastructure enabling all staff to access the hospital intranet and clinical applications during operating hours. A telephone-based registration procedure registered patients from the field into our admit/discharge/transfer system, which interfaced with the institutional electronic health record (EHR). We developed and implemented a computerized physician order entry set in our EHR with prefilled values to permit quick ordering of medications, imaging, and laboratory testing. We also developed and implemented a structured clinician note to facilitate care documentation and clinical data extraction.

RESULTS

Our MSU began operating on October 3, 2016. As of April 27, 2017, the MSU transported 49 patients, of whom 16 received tissue plasminogen activator (t-PA). Zero technical problems impacting patient care were reported around registration, order entry, or intranet access. Two onboard network failures occurred, resulting in computed tomography scanner malfunctions, although no patients became ineligible for time-sensitive treatment as a result. Thirteen (26.5%) clinical notes contained at least one incomplete time field.

CONCLUSION

The main technical challenges encountered during the integration of our hospital's clinical information systems into our MSU were onboard network failures and incomplete clinical documentation. Future studies are necessary to determine whether such integrative efforts improve MSU care quality, and which enhancements to information systems will optimize clinical care and research efforts.

Abstract TMP17: Impaired Perfusion Imaging Predicts Recurrent Cerebrovascular Events in Symptomatic Large Vessel Stenosis

Importance: Large vessel disease (LVD) stroke subtype carries the highest risk of early recurrent stroke, reaching up to 30% in the first few days. Predictors of early recurrence have been previously described, but less is known regarding infarct expansion and other causes of neurological worsening. We aim to determine the association between impaired perfusion and neurological decline in patients with LVD subtype.

Methods: This is a single center retrospective cohort study of all consecutive patients 18 years or older with LVD admitted with a diagnosis of ischemic stroke within 24 hours from symptom onset (12/1/2016 to 3/31/2017). Patients with 1) evidence of ≥ 50% stenosis of a large intra- or extracranial artery on computerized tomography angiography (CTA); 2) symptoms referable to the territory of the affected artery and NIHSS < 15 and 3) perfusion imaging data using the RAPID processing software were included. The primary predictor was unfavorable mismatch volume ≥15 mL, defined as perfusion deficit of Tmax > 6sec volume minus infarct volume similar to neuro-interventional trials. The outcome was recurrent cerebrovascular events (RCVE) at 90 days (adjudicated independently by two vascular neurologists) defined as a decline in neurologic function in the absence of a medical cause, or new infarct or infarct extension in the territory of the affected artery. We estimated the hazard ratio (HR) and 95% confidence interval (CI) for unfavorable perfusion imaging as predictor of RCVE using univariable and multivariable Cox proportional hazards models.

Results: Sixty-eight patients met our inclusion criteria (mean age 64.7 years; 61.8% male; 58.8% intracranial LVD). When compared to patients without RCVE, patients with RCVE were more likely to have unfavorable mismatch volume [71.4% vs. 14.8%, p<0.001]. This association persisted after adjusting for sex, dual antiplatelet therapy, initial stroke severity, and intracranial location of LVD (adjusted HR 15.6, 95% CI 3.7-66.7, p<0.001).

Conclusion: Perfusion mismatch is associated with RCVE in patients with ischemic stroke due to LVD. Pursuit of more aggressive treatment and management strategies may be warranted in this population.

The neurophysiological effects of single-dose theophylline in patients with chronic stroke: A double-blind, placebo-controlled, randomized cross-over study

BACKGROUND

Reducing inhibitory neurotransmission with pharmacological agents is a potential approach for augmenting plasticity after stroke. Previous work in healthy subjects showed diminished intracortical inhibition after administration of theophylline.

OBJECTIVE

We assessed the effect of single-dose theophylline on intracortical and interhemispheric inhibition in patients with chronic stroke, in a double-blind, placebo-controlled, cross-over study.

METHODS

Eighteen subjects were randomly administered 300 mg of extended-release theophylline or placebo. Immediately and 5 hours following administration, transcranial magnetic stimulation was used to assess bihemispheric resting motor threshold, short-interval intracortical inhibition, long-interval intracortical inhibition, and interhemispheric inhibition. Adverse effects on cardiovascular, neurological, and motor performance outcomes were also surveilled. Change between morning and afternoon sessions were compared across conditions. One week later, patients underwent the same assessments after crossing over to the opposite experimental condition. Subjects and investigators were blinded to the experimental condition during data acquisition and analysis.

RESULTS

For both hemispheres, changes in intracortical or interhemispheric neurophysiology were comparable under theophylline and placebo conditions. Theophylline induced no adverse neurological, cardiovascular, or motor performance effects. For both conditions and hemipsheres, the baseline level of inhibition inversely correlated with its change between sessions: less baseline inhibition (i.e. disinhibition) was associated with a strengthening in inhibition over the day, and vice versa.

CONCLUSION

A single dose of theophylline is well-tolerated by patients with chronic stroke, but does not alter cortical excitability. The inverse relationship between baseline inhibition and its change suggests the existence of a homeostatic process. The lack of effect on cortical inhibition may be related to an insufficiently long exposure to theophylline, or to differential responsiveness of disinhibited neural circuitry in patients with stroke.