Projections of Endovascular Therapy-Eligible Patients With Stroke for the US Population.

BACKGROUND: As stroke endovascular thrombectomy (EVT) treatment indications expand, understanding population-based EVT eligibility becomes critical for resource planning. We aimed to project current and future population-based EVT eligibility in the United States. METHODS: We conducted a post hoc analysis of the physician-adjudicated GCNKSS (Greater Cincinnati Northern Kentucky Stroke Study; 2015 epoch), a population-based, cross sectional, observational study of stroke incidence, treatment, and outcomes across a 5-county region. All hospitalized patients ≥18 years of age with acute ischemic stroke were ascertained using the International Classification of Diseases, Ninth Revision codes 430-436 and Tenth Revision codes I60-I67 and G45-G46 and extrapolated to the US adult census 2020. We determined the rate of EVT eligibility within the GCNKSS population using time from last known well to presentation (0-5 versus 5-23 hours), presenting National Institutes of Health Stroke Scale, and prestroke modified Rankin Scale. Both conservative and liberal estimates of prevalence of large vessel occlusion and large core were then applied based on literature review (unavailable within the 2015 GCNKSS). This eligibility was then extrapolated to the 2020 US population. RESULTS: Of the 1 057 183 adults within GCNKSS in 2015, 2741 had an ischemic stroke and 2176 had data available for analysis. We calculated that 8659 to 17 219 patients (conservative to liberal) meet the current guideline-recommended EVT criteria (nonlarge core, no prestroke disability, and National Institutes of Health Stroke Scale score ≥6) in the United States. Estimates (conservative to liberal) for expanded EVT eligibility subpopulations include (1) 5316 to 10 635 by large core; (2) 10 635 to 21 270 by mild presenting deficits with low National Institutes of Health Stroke Scale score; (3) 13 572 to 27 089 by higher prestroke disability; and (4) 7039 to 14 180 by >1 criteria. These expanded eligibility subpopulations amount to 36 562 to 73 174 patients. CONCLUSIONS: An estimated 8659 to 17 219 adult patients in the United States met strict EVT eligibility criteria in 2020. A 4-fold increase in population-based EVT eligibility can be anticipated with incremental adoption of recent or future positive trials. US stroke systems need to be rapidly optimized to handle all EVT-eligible patients with stroke.

Trends in Disparities in Advanced Neuroimaging Utilization in Acute Stroke: A Population-Based Study.

BACKGROUND: Our primary objective was to evaluate if disparities in race, sex, age, and socioeconomic status (SES) exist in utilization of advanced neuroimaging in year 2015 in a population-based study. Our secondary objective was to identify the disparity trends and overall imaging utilization as compared with years 2005 and 2010. METHODS: This was a retrospective, population-based study that utilized the GCNKSS (Greater Cincinnati/Northern Kentucky Stroke Study) data. Patients with stroke and transient ischemic attack were identified in the years 2005, 2010, and 2015 in a metropolitan population of 1.3 million. The proportion of imaging use within 2 days of stroke/transient ischemic attack onset or hospital admission date was computed. SES determined by the percentage below the poverty level within a given respondent's US census tract of residence was dichotomized. Multivariable logistic regression was used to determine the odds of advanced neuroimaging use (computed tomography angiogram/magnetic resonance imaging/magnetic resonance angiogram) for age, race, gender, and SES. RESULTS: There was a total of 10 526 stroke/transient ischemic attack events in the combined study year periods of 2005, 2010, and 2015. The utilization of advanced imaging progressively increased (48% in 2005, 63% in 2010, and 75% in 2015 [P<0.001]). In the combined study year multivariable model, advanced imaging was associated with age and SES. Younger patients (≤55 years) were more likely to have advanced imaging compared with older patients (adjusted odds ratio, 1.85 [95% CI, 1.62-2.12]; P<0.01), and low SES patients were less likely to have advanced imaging compared with high SES (adjusted odds ratio, 0.83 [95% CI, 0.75-0.93]; P<0.01). A significant interaction was found between age and race. Stratified by age, the adjusted odds of advanced imaging were higher for Black patients compared with White patients among older patients (>55 years; adjusted odds ratio, 1.34 [95% CI, 1.15-1.57]; P<0.01), but no racial differences among the young. CONCLUSIONS: Racial, age, and SES-related disparities exist in the utilization of advanced neuroimaging for patients with acute stroke. There was no evidence of a change in trend of these disparities between the study periods.

Substance Use and Performance of Toxicology Screens in the Greater Cincinnati Northern Kentucky Stroke Study.

BACKGROUND: Though stroke risk factors such as substance use may vary with age, less is known about trends in substance use over time or about performance of toxicology screens in young adults with stroke. METHODS: Using the Greater Cincinnati Northern Kentucky Stroke Study, a population-based study in a 5-county region comprising 1.3 million people, we reported the frequency of documented substance use (cocaine/marijuana/opiates/other) obtained from electronic medical record review, overall and by race/gender subgroups among physician-adjudicated stroke events (ischemic and hemorrhagic) in adults 20 to 54 years of age. Secondary analyses included heavy alcohol use and cigarette smoking. Data were reported for 5 one-year periods spanning 22 years (1993/1994-2015), and trends over time were tested. For 2015, to evaluate factors associated with performance of toxicology screens, multiple logistic regression was performed. RESULTS: Overall, 2152 strokes were included: 74.5% were ischemic, mean age was 45.7±7.6, 50.0% were women, and 35.9% were Black. Substance use was documented in 4.4%, 10.4%, 19.2%, 24.0%, and 28.8% of cases in 1993/1994, 1999, 2005, 2010, and 2015, respectively (Ptrend<0.001). Between 1993/1994 and 2015, documented substance use increased in all demographic subgroups. Adjusting for gender, comorbidities, and National Institutes of Health Stroke Scale, predictors of toxicology screens included Black race (adjusted odds ratio, 1.58 [95% CI, 1.02-2.45]), younger age (adjusted odds ratio, 0.70 [95% CI, 0.53-0.91], per 10 years), current smoking (adjusted odds ratio, 1.62 [95% CI, 1.06-2.46]), and treatment at an academic hospital (adjusted odds ratio, 1.80 [95% CI, 1.14-2.84]). After adding chart-reported substance use to the model, only chart-reported substance abuse and age were significant. CONCLUSIONS: In a population-based study of young adults with stroke, documented substance use increased over time, and documentation of substance use was higher among Black compared with White individuals. Further work is needed to confirm race-based disparities and trends in substance use given the potential for bias in screening and documentation. Findings suggest a need for more standardized toxicology screening.

Ischemic Stroke, Inflammation, and Endotheliopathy in COVID-19 Patients.

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Expedited and Comprehensive Management of Low-Risk TIA Patients in the Emergency Department is Safe and Less Costly.

OBJECTIVES: Transient ischemic attack (TIA) can be a warning sign of an impending stroke. The objective of our study is to assess the feasibility, safety, and cost savings of a comprehensive TIA protocol in the emergency room for low-risk TIA patients. MATERIALS AND METHODS: This is a retrospective, single-center cohort study performed at an academic comprehensive stroke center. We implemented an emergency department-based TIA protocol pathway for low-risk TIA patients (defined as ABCD2 score < 4 and without significant vessel stenosis) who were able to undergo vascular imaging and a brain MRI in the emergency room. Patients were set up with rapid outpatient follow-up in our stroke clinic and scheduled for an outpatient echocardiogram, if indicated. We compared this cohort to TIA patients admitted prior to the implementation of the TIA protocol who would have qualified. Outcomes of interest included length of stay, hospital cost, radiographic and echocardiogram findings, recurrent neurovascular events within 30 days, and final diagnosis. RESULTS: A total of 138 patients were assessed (65 patients in the pre-pathway cohort, 73 in the expedited, post-TIA pathway implementation cohort). Average time from MRI order to MRI end was 6.4 h compared to 2.3 h in the pre- and post-pathway cohorts, respectively (p < 0.0001). The average length of stay for the pre-pathway group was 28.8 h in the pre-pathway cohort compared to 7.7 h in the post-pathway cohort (p < 0.0001). There were no differences in neuroimaging or echocardiographic findings. There were no differences in the 30 days re-presentation for stroke or TIA or mortality between the two groups. The direct cost per TIA admission was $2,944.50 compared to $1,610.50 for TIA patients triaged through the pathway at our institution. CONCLUSIONS: This study demonstrates the feasibility, safety, and cost-savings of a comprehensive, emergency department-based TIA protocol. Further study is needed to confirm overall benefit of an expedited approach to TIA patient management and guide clinical practice recommendations.

Fixed Compared With Autoregulation-Oriented Blood Pressure Thresholds After Mechanical Thrombectomy for Ischemic Stroke.

Background and Purpose- Loss of cerebral autoregulation in the acute phase of ischemic stroke leaves patients vulnerable to blood pressure (BP) changes. Effective BP management after endovascular thrombectomy may protect the brain from hypoperfusion or hyperperfusion. In this observational study, we compared personalized, autoregulation-based BP targets to static systolic BP thresholds. Methods- We prospectively enrolled 90 patients undergoing endovascular thrombectomy for stroke. Autoregulatory function was continuously measured by interrogating changes in near-infrared spectroscopy-derived tissue oxygenation (a cerebral blood flow surrogate) in response to changes in mean arterial pressure. The resulting autoregulatory index was used to trend the BP range at which autoregulation was most preserved. Percent time that mean arterial pressure exceeded the upper limit of autoregulation or decreased below the lower limit of autoregulation was calculated for each patient. Time above fixed systolic BP thresholds was computed in a similar fashion. Functional outcome was measured with the modified Rankin Scale at 90 days. Results- Personalized limits of autoregulation were successfully computed in all 90 patients (age 71.6±16.2, 47% female, mean National Institutes of Health Stroke Scale 13.9±5.7, monitoring time 28.0±18.4 hours). Percent time with mean arterial pressure above the upper limit of autoregulation associated with worse 90-day outcomes (odds ratio per 10% 1.84 [95% CI, 1.3-2.7] P=0.002), and patients with hemorrhagic transformation spent more time above the upper limit of autoregulation (10.9% versus 16.0%, P=0.042). Although there appeared to be a nonsignificant trend towards worse outcome with increasing time above systolic BP thresholds of 140 mm Hg and 160 mm Hg, the effect sizes were smaller compared with the personalized approach. Conclusions- Noninvasive determination of personalized BP thresholds for stroke patients is feasible. Deviation from these limits may increase risk of further brain injury and poor functional outcome. This approach may present a better strategy compared with the classical approach of maintaining systolic BP below a predetermined value, though a randomized trial is needed to determine the optimal approach for hemodynamic management.

Stroke Code Presentations, Interventions, and Outcomes Before and During the COVID-19 Pandemic.

BACKGROUND: Anecdotal reports suggest fewer patients with stroke symptoms are presenting to hospitals during the coronavirus disease 2019 (COVID-19) pandemic. We quantify trends in stroke code calls and treatments at 3 Connecticut hospitals during the local emergence of COVID-19 and examine patient characteristics and stroke process measures at a Comprehensive Stroke Center (CSC) before and during the pandemic. METHODS: Stroke code activity was analyzed from January 1 to April 28, 2020, and corresponding dates in 2019. Piecewise linear regression and spline models identified when stroke codes in 2020 began to decline and when they fell below 2019 levels. Patient-level data were analyzed in February versus March and April 2020 at the CSC to identify differences in patient characteristics during the pandemic. RESULTS: A total of 822 stroke codes were activated at 3 hospitals from January 1 to April 28, 2020. The number of stroke codes/wk decreased by 12.8/wk from February 18 to March 16 (P=0.0360) with nadir of 39.6% of expected stroke codes called from March 10 to 16 (30% decrease in total stroke codes during the pandemic weeks in 2020 versus 2019). There was no commensurate increase in within-network telestroke utilization. Compared with before the pandemic (n=167), pandemic-epoch stroke code patients at the CSC (n=211) were more likely to have histories of hypertension, dyslipidemia, coronary artery disease, and substance abuse; no or public health insurance; lower median household income; and to live in the CSC city (P<0.05). There was no difference in age, sex, race/ethnicity, stroke severity, time to presentation, door-to-needle/door-to-reperfusion times, or discharge modified Rankin Scale. CONCLUSIONS: Hospital presentation for stroke-like symptoms decreased during the COVID-19 pandemic, without differences in stroke severity or early outcomes. Individuals living outside of the CSC city were less likely to present for stroke codes at the CSC during the pandemic. Public health initiatives to increase awareness of presenting for non-COVID-19 medical emergencies such as stroke during the pandemic are critical.

Cerebellar Hippocampal and Basal Nuclei Transient Edema with Restricted diffusion (CHANTER) Syndrome.

BACKGROUND: Abnormal restricted diffusion on magnetic resonance imaging is often associated with ischemic stroke or anoxic injury, but other conditions can present similarly. We present six cases of an unusual but consistent pattern of restricted diffusion in bilateral hippocampi and cerebellar cortices. This pattern of injury is distinct from typical imaging findings in ischemic, anoxic, or toxic injury, suggesting it may represent an under-recognized clinicoradiographic syndrome. Despite initial presentation with stupor or coma in the context of obstructive hydrocephalus, patients may have acceptable outcomes if offered early intervention. METHODS: We identified an ad hoc series of patients at our two institutions between years 2014 and 2017 who presented to the neurocritical care unit with severe, otherwise unexplained cerebellar edema and retrospectively identified several commonalities in history, presentation, and imaging. RESULTS: Between two institutions, we identified six patients-ages 33-59 years, four male-with similar presentations of decreased level of consciousness in the context of intoxicant exposure, with acute cytotoxic edema of the cerebellar cortex, hippocampi, and aspects of the basal nuclei. All patients presented with severe cerebellar edema which led to obstructive hydrocephalus requiring aggressive medical and/or surgical management. The five patients who survived to discharge demonstrated variable degrees of physical and memory impairment on discharge and at follow-up. CONCLUSIONS: We present findings of a potentially novel syndrome involving a distinct pattern of cerebellar and hippocampal restricted diffusion, with imaging and clinical characteristics distinct from ischemic stroke, hypoxic injury, and known toxidromes and leukoencephalopathies. Given the potential for favorable outcome despite early obstructive hydrocephalus, early identification and treatment of this syndrome are critical.

Impact of Poverty on Stroke Recurrence: A Population-Based Study.

BACKGROUND AND OBJECTIVES: Poverty is associated with greater stroke incidence. The relationship between poverty and stroke recurrence is less clear. METHODS: In this population-based study, incident strokes within the Greater Cincinnati/Northern Kentucky region were ascertained during the 2015 study period and followed up for recurrence until December 31, 2018. The primary exposure was neighborhood socioeconomic status (nSES), defined by the percentage of households below the federal poverty line in each census tract in 4 categories (≤5%, >5%-10%, >10%-25%, >25%). Poisson regression models provided recurrence rate estimates per 100,000 residents using population data from the 2015 5-year American Community Survey, adjusting for age, sex, and race. In a secondary analysis, Cox models allowed for the inclusion of vascular risk factors in the assessment of recurrence risk by nSES among those with incident stroke. RESULTS: Of 2,125 patients with incident stroke, 245 had a recurrent stroke during the study period. Poorer nSES was associated with increased stroke recurrence, with rates of 12.5, 17.5, 25.4, and 29.9 per 100,000 in census tracts with ≤5%, >5%-10%, >10%-25%, and >25% below the poverty line, respectively (p < 0.01). The relative risk (95% CI) for recurrent stroke among Black vs White individuals was 2.54 (1.91-3.37) before adjusting for nSES, and 2.00 (1.47-2.74) after adjusting for nSES, a 35.1% decrease. In the secondary analysis, poorer nSES (HR 1.74, 95% CI 1.10-2.76 for lowest vs highest category) and Black race (HR 1.31, 95% CI 1.01-1.70) were both independently associated with recurrence risk, though neither retained significance after full adjustment. Age, diabetes, and left ventricular hypertrophy were associated with increased recurrence risk in fully adjusted models. DISCUSSION: Residents of poorer neighborhoods had a dose-dependent increase in stroke recurrence risk, and neighborhood poverty accounted for approximately one-third of the excess risk among Black individuals. These results highlight the importance of poverty, race, and the intersection of the 2 as potent drivers of stroke recurrence.

Racial Disparities in Blood Pressure at Time of Acute Ischemic Stroke Presentation: A Population Study.

BACKGROUND: Hypertension is a stroke risk factor with known disparities in prevalence and management between Black and White patients. We sought to identify if racial differences in presenting blood pressure (BP) during acute ischemic stroke exist. METHODS AND RESULTS: Adults with acute ischemic stroke presenting to an emergency department within 24 hours of last known normal during study epochs 2005, 2010, and 2015 within the Greater Cincinnati/Northern Kentucky Stroke Study were included. Demographics, histories, arrival BP, National Institutes of Health Stroke Scale score, and time from last known normal were collected. Multivariable linear regression was used to determine differences in mean BP between Black and White patients, adjusting for age, sex, National Institutes of Health Stroke Scale score, history of hypertension, hyperlipidemia, smoking, stroke, body mass index, and study epoch. Of 4048 patients, 853 Black and 3195 White patients were included. In adjusted analysis, Black patients had higher presenting systolic BP (161 mm Hg [95% CI, 159-164] versus 158 mm Hg [95% CI, 157-159], P<0.01), diastolic BP (86 mm Hg [95% CI, 85-88] versus 83 mm Hg [95% CI, 82-84], P<0.01), and mean arterial pressure (111 mm Hg [95% CI, 110-113] versus 108 mm Hg [95% CI, 107-109], P<0.01) compared with White patients. In adjusted subanalysis of patients <4.5 hours from last known normal, diastolic BP (88 mm Hg [95% CI, 86-90] versus 83 mm Hg [95% CI, 82-84], P<0.01) and mean arterial pressure (112 mm Hg [95% CI, 110-114] versus 108 mm Hg [95% CI, 107-109], P<0.01) were also higher in Black patients. CONCLUSIONS: This population-based study suggests differences in presenting BP between Black and White patients during acute ischemic stroke. Further study is needed to determine whether these differences influence clinical decision-making, outcome, or clinical trial eligibility.

Acute and subacute neurovascular impact of cryptogenic air emboli.

Background: Cerebral air embolism is a rare cause of acute ischemic stroke that is becoming increasingly well-described in the literature. However, the mechanism and severity of this type of injury can vary, with ischemia typically emerging early in the course of care. To the best of our knowledge, delayed ischemia in this setting has not yet been described. Case Description: A stroke code was called for an unresponsive, hospitalized, 75-year-old man. A computerized tomography (CT) scan of the head revealed air within the right greater than left hemispheric cortical veins with loss of sulcation, concerning for developing ischemia, and CT angiography revealed absent opacification of the distal cortical vessels in the right anterior cerebral artery and middle cerebral artery territories. Magnetic resonance imaging (MRI) of the brain was obtained 5.75 h after the patient's last known well-showed small areas of subtle cortical diffusion restriction. Follow-up CT head within 24 h showed near-complete resolution of the air emboli after treatment with 100% fraction of inspired oxygen on mechanical ventilation. Subsequent MRI, performed 4 days after the initial event, showed extensive cortical diffusion restriction and cerebral edema crossing vascular territories. Conclusion: This case highlights that cerebral air emboli can cause delayed ischemia that may not be appreciated on initial imaging. As such, affected patients may require intensive neurocritical care management, close neurologic monitoring, and repeat imaging irrespective of initial radiographic findings.

Portable, low-field magnetic resonance imaging enables highly accessible and dynamic bedside evaluation of ischemic stroke.

Brain imaging is essential to the clinical management of patients with ischemic stroke. Timely and accessible neuroimaging, however, can be limited in clinical stroke pathways. Here, portable magnetic resonance imaging (pMRI) acquired at very low magnetic field strength (0.064 T) is used to obtain actionable bedside neuroimaging for 50 confirmed patients with ischemic stroke. Low-field pMRI detected infarcts in 45 (90%) patients across cortical, subcortical, and cerebellar structures. Lesions as small as 4 mm were captured. Infarcts appeared as hyperintense regions on T2-weighted, fluid-attenuated inversion recovery and diffusion-weighted imaging sequences. Stroke volume measurements were consistent across pMRI sequences and between low-field pMRI and conventional high-field MRI studies. Low-field pMRI stroke volumes significantly correlated with stroke severity and functional outcome at discharge. These results validate the use of low-field pMRI to obtain clinically useful imaging of stroke, setting the stage for use in resource-limited environments.

Prior Stroke and Age Predict Acute Ischemic Stroke Among Hospitalized COVID-19 Patients: A Derivation and Validation Study.

Objectives: Our objective was to identify characteristics associated with having an acute ischemic stroke (AIS) among hospitalized COVID-19 patients and the subset of these patients with a neurologic symptom. Materials and Methods: Our derivation cohort consisted of COVID-19 patients admitted to Yale-New Haven Health between January 3, 2020 and August 28, 2020 with and without AIS. We also studied a sub-cohort of hospitalized COVID-19 patients demonstrating a neurologic symptom with and without an AIS. Demographic, clinical, and laboratory results were compared between AIS and non-AIS patients in the full COVID-19 cohort and in the sub-cohort of COVID-19 patients with a neurologic symptom. Multivariable logistic regression models were built to predict ischemic stroke risk in these two COVID-19 cohorts. These 2 models were externally validated in COVID-19 patients hospitalized at a major health system in New York. We then compared the distribution of the resulting predictors in a non-COVID ischemic stroke control cohort. Results: A total of 1,827 patients were included in the derivation cohort (AIS N = 44; no AIS N = 1,783). Among all hospitalized COVID-19 patients, history of prior stroke and platelet count ≥ 200 × 1,000/µL at hospital presentation were independent predictors of AIS (derivation AUC 0.89, validation AUC 0.82), irrespective of COVID-19 severity. Among hospitalized COVID-19 patients with a neurologic symptom (N = 827), the risk of AIS was significantly higher among patients with a history of prior stroke and age <60 (derivation AUC 0.83, validation AUC 0.81). Notably, in a non-COVID ischemic stroke control cohort (N = 168), AIS patients were significantly older and less likely to have had a prior stroke, demonstrating the uniqueness of AIS patients with COVID-19. Conclusions: Hospitalized COVID-19 patients who demonstrate a neurologic symptom and have either a history of prior stroke or are of younger age are at higher risk of ischemic stroke.

Stroke Center Certification Is Associated With Improved Guideline Concordance.

Measurement of quality of stroke care has become increasingly important, but data come mostly from programs in hospitals that choose to participate in certification programs, which may not be representative of the care provided in nonparticipating hospitals. The authors sought to determine differences in quality of care metric concordance for acute ischemic stroke among hospitals designated as a primary stroke center, comprehensive stroke center, and non-stroke center in a population-based epidemiologic study. Significant differences were found in both patient demographics and in concordance with guideline-based quality metrics. These differences may help inform quality improvement efforts across hospitals involved in certification as well as those that are not.