Racial and Ethnic Disparities in the Utilization of Thrombectomy for Acute Stroke

Ten-year trends, disparities, and clinical impact of stroke thrombectomy and thrombolysis: a single center experience 2012-2021

OBJECTIVES

As indications for acute ischemic stroke treatment expand, it is unclear whether disparities in treatment utilization and outcome still exist. The main objective of this study was to investigate disparities in acute ischemic stroke treatment and determine impact on outcome.

MATERIALS AND METHODS

Retrospective observational cohort study of consecutive ischemic stroke admissions to a comprehensive stroke center from 2012-2021 was performed. Primary exposure was intravenous thrombolysis and/or endovascular thrombectomy. Primary end points were discharge modified Rankin Scale, home disposition, and expired/hospice. Multivariable logistic regression analyses were conducted to elucidate disparities in treatment utilization and determine impact on outcome.

RESULTS

Of 517,615 inpatient visits, there were 7,540 (1.46%) ischemic stroke admissions, increasing from 1.14% to 1.79% from 2012-2021. Intravenous thrombolysis significantly decreased from 14.4% to 9.8% while endovascular thrombectomy significantly increased from 0.8% to 10.5%. Both intravenous thrombolysis and endovascular thrombectomy increased odds of discharge home and modified Rankin Scale 0-2, and thrombectomy decreased odds of expired/hospice. After adjusting for covariates, decreased odds of thrombectomy was associated with Medicaid insurance (Odds Ratio [95% Confidence Interval] 0.55 [0.32-0.93]), age 80+ (0.49 [0.35-0.69]), prior stroke (0.49 [0.31-0.77]), and diabetes mellitus (0.55 [0.39-0.79]), while low median household income (<$80,000/year) increased odds of no acute treatment (1.34 [1.16-1.56]). No sex or racial disparities were observed. Medicaid and low-income were not associated with worse clinical outcomes.

CONCLUSIONS

Less endovascular thrombectomy occurred in Medicaid, older, prior stroke, and diabetic patients, while low-income was associated with no treatment. The observed socioeconomic disparities did not impact discharge outcome.

Challenges to Widespread Implementation of Stroke Thrombectomy

Endovascular treatment (EVT) for acute ischemic stroke is one of the most efficacious and effective treatments in medicine, yet globally, its implementation remains limited. Patterns of EVT underutilization exist in virtually any health care system and range from a complete lack of access to selective undertreatment of certain patient subgroups. In this review, we outline different patterns of EVT underutilization and possible causes. We discuss common challenges and bottlenecks that are encountered by physicians, patients, and other stakeholders when trying to establish and expand EVT services in different scenarios and possible pathways to overcome these challenges. Lastly, we discuss the importance of implementation research studies, strategic partnerships, and advocacy efforts to mitigate EVT underutilization.

Disparities in access to and timing of interventional therapies for pulmonary embolism across the United States

BACKGROUND

Interventional therapies (ITs) are an emerging treatment modality for pulmonary embolism (PE); however, the degree of racial, sex-based, and sociodemographic disparities in access and timing is unknown.

OBJECTIVES

To investigate barriers to access and timing of ITs for PE across the United States.

METHODS

A retrospective cohort study utilizing the Nationwide Inpatient Sample from 2016-2020 included adult patients with PE. The use of ITs (mechanical thrombectomy and catheter-directed thrombolysis) was identified via International Classification of Diseases 10th revision codes. Early IT was defined as procedure performed within the first 2 days after admission.

RESULTS

A total of 27 805 273 records from the 2016-2020 Nationwide Inpatient Sample database were examined. There were 387 514 (1.4%) patients with PE, with 14 249 (3.6%) of them having undergone IT procedures (11 115 catheter-directed thrombolysis, 2314 thrombectomy, and 780 both procedures). After multivariate adjustment, factors associated with less use of IT included Black race (odds ratio [OR], 0.90; 95% CI, 0.86-0.94; P < .01), Hispanic race (OR, 0.73; 95% CI, 0.68-0.79; P < .01), female sex (OR, 0.88; 95% CI, 0.85-0.91; P < .01), treatment in a rural hospital (OR, 0.49; 95% CI, 0.44-0.54; P < .01), and lack of private insurance (Medicare OR, 0.77; 95% CI, 0.73-0.80; P < .01; Medicaid OR, 0.65; 95% CI, 0.61-0.69; P < .01; no coverage OR, 0.87; 95% CI, 0.82-0.93; P < .01). Among the patients who received IT, 11 315 (79%) procedures were conducted within 2 days of admission and 2934 (21%) were delayed. Factors associated with delayed procedures included Black race (OR, 1.12; 95% CI, 1.01-1.26; P = .04), Hispanic race (OR, 1.52; 95% CI, 1.28-1.80; P < .01), weekend admission (OR, 1.37; 95% CI, 1.25-1.51; P < .01), Medicare coverage (OR, 1.24; 95% CI, 1.10-1.40; P < .01), and Medicaid coverage (OR, 1.29; 95% CI, 1.12-1.49; P < .01).

CONCLUSION

Significant racial, sex-based, and geographic barriers exist in overall access to IT for PE in the United States.

African American patients have a higher probability of cognitive impairment after incident stroke: An analysis of national electronic health record data

BACKGROUND

Cognitive impairment (CI) and stroke are diseases with significant disparities in race and geography. Post stroke cognitive impairment (PSCI) can be as high as 15-70 % but few studies have utilized large administrative or electronic health records (EHR) to evaluate trends in PSCI. We utilized an EHR database to evaluate for disparities in PSCI in a large sample of patients after first recorded stroke to evaluate for disparities in race.

METHODS

This is a retrospective cohort analysis of Cerner Health Facts® EHR database, which is comprised of EHR data from hundreds of hospitals/clinics in the US from 2009-2018. We evaluated patients ≥40 years of age with a first time ischemic stroke (IS) diagnosis for PSCI using ICD9/10 codes for both conditions. Patients with first stroke in the Cerner database and no pre-existing cognitive impairment were included, we compared hazard ratios for developing PSCI for patient characteristics RESULTS: A total of 150,142 IS patients with follow-up data and no pre-existing evidence of CI were evaluated. Traditional risk factors of age, female sex, kidney injury, hypertension, and hyperlipidemia were associated with PSCI. Only African American stroke survivors had a higher probability of developing PSCI compared to White survivors (HR 1.347, 95 % CI (1.270, 1.428)) and this difference was most prominent in the South. Among those to develop PSCI, median time to documentation was 1.8 years in African American survivors.

CONCLUSION

In a large national database, African American stroke survivors had a higher probability of PSCI five years after stroke than White survivors.

Racial disparities in access to, and outcomes of, acute ischaemic stroke treatments in the USA

BACKGROUND

Racism contributes to higher comorbid risk factors and barriers to preventive measures for black Americans. Advancements in systems of care, tissue plasminogen activator (tPA) availability and endovascular thrombectomy (ET) have impacted practice and outcomes while outpacing contemporary investigation into acute ischaemic stroke (AIS) care disparities. We examined whether recent data suggest ongoing disparity in AIS interventions and outcomes, and if hospital characteristics affect disparities.

METHODS

We examined 2016-2019 fee-for-service Medicare inpatient data. We ran unadjusted logistic regression models to calculate ORs and 95% CI for two interventions (tPA and ET) and four outcomes (inpatient mortality, 30-day mortality, discharge home and outpatient visit within 30 days), with the main predictor black versus white race, additionally adjusting for demographics, hospital characteristics, stroke severity and comorbidities.

RESULTS

805 181 AIS admissions were analysed (12.4% black, 87.6% white). Compared with white patients, black patients had reduced odds of receiving tPA (OR 0.71, 95% CI 0.69 to 0.74, p<0.0001) and ET (0.69, 95% CI 0.65 to 0.72, p<0.0001). After tPA, black patients had reduced odds of 30-day mortality (0.77, 95% CI 0.72 to 0.82, p<0.0001), discharge home (0.72, 95% CI 0.68 to 0.77, p<0.0001) and outpatient visit within 30 days (0.89, 95% CI 0.84 to 0.95, p=0.0002). After ET, black patients had reduced odds of 30-day mortality (0.71, 95% CI 0.63 to 0.79, p<0.0001) and discharge home (0.75, 95% CI 0.64 to 0.88, p=0.0005). Adjusted models showed little difference in the magnitude, direction or significance of the main effects.

CONCLUSIONS

Black patients were less likely to receive AIS treatments, and if treated had lower likelihood of 30-day mortality, discharge home and outpatient visits. Despite advancements in practice and therapies, racial disparities remain in the modern era of AIS care and are consistent with inequalities previously identified over the last 20 years. The impact of hospital attributes on AIS care disparities warrants further investigation.

Ethnic and Gender Variations in Ischemic Stroke Patterns among Arab Populations in Northern Israel: A Preliminary Exploration towards Culturally Aware Personalized Stroke Care

The Galilee region of Israel boasts a rich ethnic diversity within its Arab population, encompassing distinct Muslim, Christian, Druze, and Bedouin communities. This preliminary exploratory study uniquely examined potential ethnic and gender differences in ischemic stroke characteristics across these Arab subgroups, which are seldom investigated separately in Israel and are typically studied as a homogeneous "Arab" sector, despite significant variations in their ethnicity, culture, customs, and genetics. The current study aimed to comparatively evaluate stroke characteristics, including recurrence rates, severity, and subtypes, within and across these distinct ethnic groups and between genders. When examining the differences in stroke characteristics between ethnic groups, notable findings emerged. The Bedouin population exhibited significantly higher rates of recurrent strokes than Muslims (M = 0.55, SD = 0.85 vs. M = 0.25, SD = 0.56; p < 0.05). Large vessel strokes were significantly more prevalent among Christians (30%) than Druze (9.9%; p < 0.05). Regarding gender differences within each ethnic group, several disparities were observed. Druze women were six times more likely to experience moderate to severe strokes than their male counterparts (p < 0.05). Interestingly, Druze women also exhibited a higher representation of cardio-embolic stroke (19.8%) compared with Druze men (4.6%; p < 0.001). These findings on the heterogeneity in stroke characteristics across Arab ethnic subgroups and by gender underscore the need to reconsider the approach that views all ethnic groups comprising the Arab sector in Israel as a homogeneous population; instead, they should be investigated as distinct communities with unique stroke profiles, requiring tailored culturally aware community-based prevention programs and personalized therapeutic models. The identified patterns may guide future research to develop refined, individualized, and preventive treatment approaches targeting the distinct risk factors, healthcare contexts, and prevention needs of these diverse Arab populations.

Ethical Considerations in Endovascular Thrombectomy for Stroke

INTRODUCTION

Stroke is a leading cause of morbidity and mortality globally. Endovascular mechanical thrombectomy is considered for patients with large vessel occlusion stroke presenting up to 24 hours from onset and is being increasingly utilized across diverse clinical contexts. Proactive consideration of distinctive ethical dimensions of endovascular thrombectomy (EVT) can enable stroke care teams to deliver goal-concordant care to appropriately selected patients with stroke but have been underexplored.

METHODS

A narrative review with case examples was conducted.

RESULTS

We explain and critically evaluate the application of foundational bioethical principles and narrative ethics to the practice of EVT, highlight key ethical issues that may emerge in neuroendovascular practice and develop an ethical framework to aid in the responsible use of EVT for people with large-vessel occlusive ischemic stroke.

CONCLUSIONS

EVT for stroke introduces important ethical considerations. Salient challenges include decision-making capacity and informed consent, the telos of EVT, uncertainty, access to care, and resource allocation. An ethical framework focusing on combining patient values and preferences with the best available evidence in the context of a multidisciplinary care team is essential to ensure that the benefits of EVT are responsibly achieved and sustained.

Health Care Disparities in Stroke Rehabilitation

Stroke outcomes are influenced by factors such as education, lifestyle, and access to care, which determine the extent of functional recovery. Disparities in stroke rehabilitation research have traditionally included age, race/ethnicity, and sex, but other areas make up a gap in the literature. This article conducted a literature review of original research articles published between 2008 and 2022. The article also expands on research that highlights stroke disparities in risk factors, rehabilitative stroke care, language barriers, outcomes for stroke survivors, and interventions focused on rehabilitative stroke disparities.

Addressing Disparities in Acute Stroke Management and Prognosis

There are now abundant data demonstrating disparities in acute stroke management and prognosis; however, interventions to reduce these disparities remain limited. This special report aims to provide a critical review of the current landscape of disparities in acute stroke care and highlight opportunities to use implementation science to reduce disparities throughout the early care continuum. In the prehospital setting, stroke symptom recognition campaigns that have been successful in reducing prehospital delays used a multilevel approach to education, including mass media, culturally tailored community education, and professional education. The mobile stroke unit is an organizational intervention that has the potential to provide more equitable access to timely thrombolysis and thrombectomy treatments. In the hospital setting, interventions to address implicit biases among health care providers in acute stroke care decision-making are urgently needed as part of a multifaceted approach to advance stroke equity. Implementing stroke systems of care interventions, such as evidence-based stroke care protocols at designated stroke centers, can have a broader public health impact and may help reduce geographic, racial, and ethnic disparities in stroke care, although further research is needed. The long-term impact of disparities in acute stroke care cannot be underestimated. The consistent trend of longer time to treatment for Black and Hispanic people experiencing stroke has direct implications on long-term disability and independence after stroke. A learning health system model may help expedite the translation of evidence-based interventions into clinical practice to reduce disparities in stroke care.

Sex-specific racial and ethnic variations in short-term outcomes among patients with first or recurrent ischemic stroke: Paul Coverdell National Acute Stroke Program, 2016-2020

BACKGROUND AND PURPOSE

To understand the association of sex-specific race and ethnicity on the short-term outcomes of initial and recurrent ischemic stroke events.

METHODS

Using the Paul Coverdell National Acute Stroke Program from 2016-2020, we examined 426,062 ischemic stroke admissions from 629 hospitals limited to non-Hispanic White (NHW), non-Hispanic Black (NHB), and Hispanic patients. We performed multivariate logistic regression analyses to assess the combined effects of sex-specific race and ethnicity on short-term outcomes for acute ischemic stroke patients presenting with initial or recurrent stroke events. Outcomes assessed include rates of in-hospital death, discharge to home, and symptomatic intracranial hemorrhage (sICH) after reperfusion treatment.

RESULTS

Among studied patients, the likelihood of developing sICH after reperfusion treatment for initial ischemic stroke was not significantly different. The likelihood of experiencing in-hospital death among patients presenting with initial stroke was notably higher among NHW males (AOR 1.59 [95 % CI 1.46, 1.73]), NHW females (AOR 1.34 [95 % CI 1.23, 1.45]), and Hispanic males (AOR 1.57 [95 % CI 1.36, 1.81]) when compared to NHB females. Hispanic females were more likely to be discharged home when compared to NHB females after initial stroke event (AOR 1.32 [95 % CI 1.23, 1.41]). NHB males (AOR 0.90 [95 % CI 0.87, 0.94]) and NHW females (AOR 0.89 [95 % CI 0.86, 0.92]) were less likely to be discharged to home. All groups with recurrent ischemic strokes experienced higher likelihood of in-hospital death when compared to NHB females with the highest likelihood among NHW males (AOR 2.13 [95 % CI 1.87, 2.43]). Hispanic females had a higher likelihood of discharging home when compared to NHB females hospitalized for recurrent ischemic stroke, while NHB males and NHW females with recurrent ischemic stroke hospitalizations were less likely to discharge home.

CONCLUSIONS

Sex-specific race and ethnic disparities remain for short-term outcomes in both initial and recurrent ischemic stroke hospitalizations. Further studies are needed to address disparities among recurrent ischemic stroke hospitalizations.

Post-ischemic ubiquitination at the postsynaptic density reversibly influences the activity of ischemia-relevant kinases

Ubiquitin modifications alter protein function and stability, thereby regulating cell homeostasis and viability, particularly under stress. Ischemic stroke induces protein ubiquitination at the ischemic periphery, wherein cells remain viable, however the identity of ubiquitinated proteins is unknown. Here, we employed a proteomics approach to identify these proteins in mice undergoing ischemic stroke. The data are available in a searchable web interface ( https://hochrainerlab.shinyapps.io/StrokeUbiOmics/ ). We detected increased ubiquitination of 198 proteins, many of which localize to the postsynaptic density (PSD) of glutamatergic neurons. Among these were proteins essential for maintaining PSD architecture, such as PSD95, as well as NMDA and AMPA receptor subunits. The largest enzymatic group at the PSD with elevated post-ischemic ubiquitination were kinases, such as CaMKII, PKC, Cdk5, and Pyk2, whose aberrant activities are well-known to contribute to post-ischemic neuronal death. Concurrent phospho-proteomics revealed altered PSD-associated phosphorylation patterns, indicative of modified kinase activities following stroke. PSD-located CaMKII, PKC, and Cdk5 activities were decreased while Pyk2 activity was increased after stroke. Removal of ubiquitin restored kinase activities to pre-stroke levels, identifying ubiquitination as the responsible molecular mechanism for post-ischemic kinase regulation. These findings unveil a previously unrecognized role of ubiquitination in the regulation of essential kinases involved in ischemic injury.

Provider Care Segregation and Hospital-Region Racial Disparities in the United States for Acute Ischemic Stroke and Endovascular Therapy Outcomes

BACKGROUND

Reasons for racial disparities in the use and outcomes of endovascular treatment (ET) are not known. We examined patterns in care segregation for acute ischemic stroke (AIS) in the United States, and outcomes of segregation of care after ET.

METHODS AND RESULTS

We used deidentified Medicare data sets to identify AIS admissions between January 1, 2016 and December 31, 2019, using validated International Classification of Diseases, Tenth Revision (ICD-10) codes. For AIS, we calculated (1) the proportion of White patients at the hospital, (2) the proportional difference in the proportion of White patients between hospital patients and the county, and (3) provider care segregation by the dissimilarity index for ET cases. Using unadjusted and adjusted multilevel logistic models, we examined associations between measures of segregation and outcomes of discharge home, inpatient mortality, and 30-day mortality. The mean proportional difference in the proportion of White patients comparing hospitalized patients with AIS to the county race distribution was 0.015 (SD, 0.219) at the hospital level. For ET, the mean proportional difference in the proportion of White patients comparing patients receiving ET to the county race distribution was much higher, at 0.146 (SD, 0.374). The dissimilarity index for ET providers was high, with a mean of 0.48 (SD, 0.29) across all hospitals. Black patients with AIS (compared with White patients) had reduced odds of discharge home, inpatient mortality, and 30-day mortality.

CONCLUSIONS

In this national study with contemporary data in the endovascular era of AIS treatment, we found substantial evidence for segregation of care in the United States, not for only AIS in general but also especially for ET.

Gender-Based Disparity in Acute Stroke Imaging Utilization and the Impact on Treatment and Outcomes: 2012 to 2021

INTRODUCTION

Prior studies have revealed significant socio-economic disparities in neuro-imaging and treatment utilization for patients with acute ischemic stroke (AIS). In this study, we sought to evaluate whether a sex-based disparity exists in neuro-imaging and to determine its etiology and association with acute treatment and outcomes.

MATERIALS AND METHODS

This was a retrospective study of consecutive patients with AIS admitted to a comprehensive stroke center between 2012 and 2021. Patient demographic and clinical characteristics, neuro-imaging, acute treatment, and early clinical outcomes were extracted from the electronic medical records. Trend analysis, bivariate analysis of patient characteristics by sex, and multivariable logistic regression analyses were conducted.

RESULTS

Of the 7,540 AIS episodes registered from 2012 to 2021, 47.9% were female patients. After adjusting for demographic, clinical, and temporal factors, significantly higher utilization of CTA was found for male patients (odds ratio = 1.20 [95% confidence interval 1.07-1.34]), particularly from socio-economically advantaged groups, and in years 2015 and 2019, representing the years endovascular thrombectomy recommendations changed. Despite this, male patients had significantly lower intravenous thrombolysis utilization (odds ratio = 0.83 [95% confidence interval 0.71-0.96]) and similar endovascular thrombectomy rates as female patients. There were no significant sex differences in early clinical outcomes, and no relevant clinical or demographic factors explained the CT angiography utilization disparity.

CONCLUSION

Despite higher CT angiography utilization in socio-economically advantaged male patients with AIS, likely overutilization due to implicit biases following guideline updates, the rates of acute treatment, and early clinical outcomes were unaffected.

Racial and ethnic disparities in the usage and outcomes of ischemic stroke treatment in the United States

OBJECTIVES

This study explores racial and ethnic differences in 1) receiving tissue plasminogen activator (tPA) and endovascular thrombectomy (EVT) as treatment for ischemic stroke and 2) outcomes and quality of care after use of tPA or EVT in the US.

MATERIALS AND METHODS

An observational analysis of 89,035 ischemic stroke patients from the 2019 National Inpatient Sample was conducted. We performed weighted logistic regressions between race and ethnicity and 1) tPA and EVT utilization and 2) in-hospital mortality. We also performed a weighted Poisson regression between race and ethnicity and length of stay (LOS) after tPA or EVT.

RESULTS

Non-Hispanic (NH) Black patients had significantly lower odds of receiving tPA (Adjusted odds ratio [AOR] = 0.85, 95 % Confidence Internal [C.I.]: 0.80-0.91) and EVT (AOR = 0.75, 95 % CI: 0.70-0.82) than NH White patients. Minority populations (including but not limited to NH Black, Hispanic, Pacific Islander, Native American, and Asian) had significantly longer hospital LOS after treatment with tPA or EVT. We did not find a significant difference between race/ethnicity and in-hospital mortality post-tPA or EVT.

CONCLUSIONS

While we failed to find a difference in in-hospital mortality, racial and ethnic disparities are still evident in the decreased usage of tPA and EVT and longer LOSs for racial and ethnic minority patients. This study calls for interventions to expand the utilization of tPA and EVT and advance quality of care post-tPA or EVT in order to improve stroke care for minority patients.

Restoring a balanced pool of host-derived and microbiota-derived ligands of the aryl hydrocarbon receptor is beneficial after stroke

Background

Stroke is a major cause of morbidity and mortality, and its incidence increases with age. While acute therapies for stroke are currently limited to intravenous thrombolytics and endovascular thrombectomy, recent studies have implicated an important role for the gut microbiome in post-stroke neuroinflammation. After stroke, several immuno-regulatory pathways, including the aryl hydrocarbon receptor (AHR) pathway, become activated. AHR is a master regulatory pathway that mediates neuroinflammation. Among various cell types, microglia (MG), as the resident immune cells of the brain, play a vital role in regulating post-stroke neuroinflammation and antigen presentation. Activation of AHR is dependent on a dynamic balance between host-derived and microbiota-derived ligands. While previous studies have shown that activation of MG AHR by host-derived ligands, such as kynurenine, is detrimental after stroke, the effects of post-stroke changes in microbiota-derived ligands of AHR, such as indoles, is unknown. Our study builds on the concept that differential activation of MG AHR by host-derived versus microbiome-derived metabolites affects outcomes after ischemic stroke. We examined the link between stroke-induced dysbiosis and loss of essential microbiota-derived AHR ligands. We hypothesize that restoring the balance between host-derived (kynurenine) and microbiota-derived (indoles) ligands of AHR is beneficial after stroke, offering a new potential avenue for therapeutic intervention in post-stroke neuroinflammation.

Method

We performed immunohistochemical analysis of brain samples from stroke patients to assess MG AHR expression after stroke. We used metabolomics analysis of plasma samples from stroke and non-stroke control patients with matched comorbidities to determine the levels of indole-based AHR ligands after stroke. We performed transient middle cerebral artery occlusion (MCAO) in aged (18 months) wild-type (WT) and germ-free (GF) mice to investigate the effects of post-stroke treatment with microbiota-derived indoles on outcome. To generate our results, we employed a range of methodologies, including flow cytometry, metabolomics, and 16S microbiome sequencing.

Results

We found that MG AHR expression is increased in human brain after stroke and after ex vivo oxygen-glucose deprivation and reperfusion (OGD/R). Microbiota-derived ligands of AHR are decreased in the human plasma at 24 hours after ischemic stroke. Kynurenine and indoles exhibited differential effects on aged WT MG survival after ex vivoOGD/R. We found that specific indole-based ligands of AHR (indole-3-propionic acid and indole-3-aldehyde) were absent in GF mice, thus their production depends on the presence of a functional gut microbiota. Additionally, a time-dependent decrease in the concentration of these indole-based AHR ligands occurred in the brain within the first 24 hours after stroke in aged WT mice. Post-stroke treatment of GF mice with a cocktail of microbiota-derived indole-based ligands of AHR regulated MG-mediated neuroinflammation and molecules involved in antigen presentation (increased CD80, MHC-II, and CD11b). Post-stroke treatment of aged WT mice with microbiota-derived indole-based ligands of AHR reduced both infarct volume and neurological deficits at 24 hours.

Conclusion

Our novel findings provide compelling evidence that the restoration of a well-balanced pool of host-derived kynurenine-based and microbiota-derived indole-based ligands of AHR holds considerable therapeutic potential for the treatment of ischemic stroke.

Racial and Ethnic Disparities in Treatment of Critical Limb Ischemia: A National Perspective

Background Recent guidelines have emphasized the use of medical management, early diagnosis, and a multidisciplinary team to effectively treat patients with critical limb ischemia (CLI). Previous literature briefly highlighted the current racial disparities in its intervention. Herein, we analyze the trend over a 14-year time period to investigate whether the disparities gap in CLI management is closing. Methods and Results The National Inpatient Sample was queried between 2005 and 2018 for hospitalizations involving CLI. Nontraumatic amputations and revascularization were identified. Utilization trends of these procedures were compared between races (White, Black, Hispanic, Asian and Pacific Islander, Native American, and Other). Multivariable regression assessed differences in race regarding procedure usage. There were 6 904 562 admissions involving CLI in the 14-year study period. The rate of admissions in White patients who received any revascularization decreased by 0.23% (P<0.001) and decreased by 0.25% (P=0.025) for Asian and Pacific Islander patients. Among all patients, the annual rate of admission in White patients who received any amputation increased by 0.21% (P<0.001), increased by 0.19% (P=0.001) for Hispanic patients, and increased by 0.19% (P=0.012) for the Other race patients. Admissions involving Black, Hispanic, Asian and Pacific Islander, or Other race patients had higher odds of receiving any revascularization compared with White patients. All races had higher odds of receiving major amputation compared with White patients. Conclusions Our analysis highlights disparities in CLI treatment in our nationally representative sample. Non-White patients are more likely to receive invasive treatments, including major amputations and revascularization for CLI, compared with White patients.

Imaging Artificial Intelligence: A Framework for Radiologists to Address Health Equity, From the AJR Special Series on DEI

Artificial intelligence (AI) holds promise for helping patients access new and individualized health care pathways while increasing efficiencies for health care practitioners. Radiology has been at the forefront of this technology in medicine; many radiology practices are implementing and trialing AI-focused products. AI also holds great promise for reducing health disparities and promoting health equity. Radiology is ideally positioned to help reduce disparities given its central and critical role in patient care. The purposes of this article are to discuss the potential benefits and pitfalls of deploying AI algorithms in radiology, specifically highlighting the impact of AI on health equity; to explore ways to mitigate drivers of inequity; and to enhance pathways for creating better health care for all individuals, centering on a practical framework that helps radiologists address health equity during deployment of new tools.

Procedural, workforce, and reimbursement trends in neuroendovascular procedures

BACKGROUND

This study aims to define the proportion of Medicare neuroendovascular procedures performed by different specialists from 2013 to 2019, map the geographic distribution of these specialists, and trend reimbursement for these procedures.

METHODS

The Medicare Provider Utilization Database was queried for recognized neuroendovascular procedures. Data on specialists and their geographic distribution were tabulated. Reimbursement data were gathered using the Physician Fee Schedule Look-Up Tool and adjusted for inflation using the United States Bureau of Labor Statistics' Consumer Price Index Inflation calculator.

RESULTS

The neuroendovascular workforce in 2013 and 2019, respectively, was as follows: radiologists (46% vs 44%), neurosurgeons (45% vs 35%), and neurologists (9% vs 21%). Neurologists increased proportionally (p=0.03). Overall procedure numbers increased across each specialty: radiology (360%; p=0.02), neurosurgery (270%; p<0.01), and neurology (1070%; p=0.03). Neuroendovascular revascularization (CPT 61645) increased in all fields: radiology (170%; p<0.01), neurosurgery (280%; p<0.01), neurology (240%; p<0.01); central nervous system (CNS) permanent occlusion/embolization (CPT61624) in neurosurgery (67%; p=0.03); endovascular temporary balloon artery occlusion (CPT61623) in neurology (29%; p=0.04). In 2019, radiologists were the most common neuroendovascular specialists everywhere except in the Northeast where neurosurgeons predominated. Inflation adjusted reimbursement decreased for endovascular temporary balloon occlusion (CPT61623, -13%; p=0.01), CNS transcatheter permanent occlusion or embolization (CPT61624, -13%; p=0.02), non-CNS transcatheter permanent occlusion or embolization (CPT61626, -12%; p<0.01), and intracranial stent placement (CPT61635, -12%; p=0.05).

CONCLUSIONS

The number of neuroendovascular procedures and specialists increased, with neurologists becoming more predominant. Reimbursement decreased. Coordination among neuroendovascular specialists in terms of training and practice location may maximize access to acute care.

Post-ischemic ubiquitination at the postsynaptic density reversibly influences the activity of ischemia-relevant kinases

Ubiquitin modifications alter protein function and stability, thereby regulating cell homeostasis and viability, particularly under stress. Ischemic stroke induces protein ubiquitination at the ischemic periphery, wherein cells remain viable, however the identity of ubiquitinated proteins is unknown. Here, we employed a proteomics approach to identify these proteins in mice undergoing ischemic stroke. The data are available in a searchable web interface ( https://hochrainerlab.shinyapps.io/StrokeUbiOmics/ ). We detected increased ubiquitination of 198 proteins, many of which localize to the postsynaptic density (PSD) of glutamatergic neurons. Among these were proteins essential for maintaining PSD architecture, such as PSD95, as well as NMDA and AMPA receptor subunits. The largest enzymatic group at the PSD with elevated post-ischemic ubiquitination were kinases, such as CaMKII, PKC, Cdk5, and Pyk2, whose aberrant activities are well-known to contribute to post-ischemic neuronal death. Concurrent phospho-proteomics revealed altered PSD-associated phosphorylation patterns, indicative of modified kinase activities following stroke. PSD-located CaMKII, PKC, and Cdk5 activities were decreased while Pyk2 activity was increased after stroke. Removal of ubiquitin restored kinase activities to pre-stroke levels, identifying ubiquitination as the responsible molecular mechanism for post-ischemic kinase regulation. These findings unveil a previously unrecognized role of ubiquitination in the regulation of essential kinases involved in ischemic injury.

Women With Large Vessel Occlusion Acute Ischemic Stroke Are Less Likely to Be Routed to Comprehensive Stroke Centers

Background Prehospital routing of patients with large vessel occlusion (LVO) acute ischemic stroke (AIS) to centers capable of performing endovascular therapy may improve clinical outcomes. Here, we explore whether distance to comprehensive stroke centers (CSCs), stroke severity, and sex are associated with direct-to-CSC prehospital routing in patients with LVO AIS. Methods and Results In this cross-sectional study, we identified consecutive patients with LVO AIS from a prospectively collected multihospital registry throughout the greater Houston area from January 2019 to June 2020. Primary outcome was prehospital routing to CSC and was compared between men and women using modified Poisson regression including age, sex, race or ethnicity, first in-hospital National Institutes of Health Stroke Scale score, travel time, and distances to the closest primary stroke center and CSC. Among 503 patients with LVO AIS, 413 (82%) were routed to CSCs, and women comprised 46% of the study participants. Women with LVO AIS compared with men were older (73 versus 65, P<0.01) and presented with greater National Institutes of Health Stroke Scale score (14 versus 12, P=0.01). In modified Poisson regression, women were 9% less likely to be routed to CSCs compared with men (adjusted relative risk [aRR], 0.91 [0.84-0.99], P=0.024) and distance to nearest CSC ≤10 miles was associated with 38% increased chance of routing to CSC (aRR, 1.38 [1.26-1.52], P<0.001). Conclusions Despite presenting with more significant stroke syndromes and living within comparable distance to CSCs, women with LVO AIS were less likely to be routed to CSCs compared with men. Further study of the mechanisms behind this disparity is needed.

Sodium-Glucose Cotransporter-2 Inhibitors in Heart Failure With Mildly Reduced or Preserved Ejection Fraction: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Sodium-glucose cotransporter-2 inhibitors (SGLT2i) reduce the risk of heart failure (HF) hospitalizations and cardiovascular mortality among patients with HF and left ventricular ejection fraction (LVEF) ≤40%. There is emerging evidence of the benefits of SGLT2i in HF patients with a higher LVEF (>40%). We aimed to evaluate the benefits of SGLT2i in different subgroups of patients with HF and LVEF >40%.

METHODS

We searched PubMed, EMBASE, clinicaltrials.gov, Cochrane, and Google Scholar for randomized controlled trials (RCTs) comparing outcomes of SGLT2i vs placebo in patients with HF and LVEF >40%. The hazard ratios (HRs) and 95% confidence intervals (CIs) in each study were used for the meta-analysis. The primary composite outcome (PCO) was HF hospitalization or cardiovascular mortality. Secondary outcomes included HF hospitalization, cardiovascular mortality, and all-cause mortality.

RESULTS

Six RCTs with 15,989 patients were included (median follow-up = 27.3 months, 40.8% females). In patients with HF and LVEF >40%, SGLT2i were associated with significantly lower PCO compared to placebo (HR 0.80; 95% CI 0.74-0.86; P < 0.001). This was consistent across 10 of 13 subgroups examined, including LVEF. SGLT2i also reduced HF hospitalization but not cardiovascular or all-cause mortality. Patients <65 years old, from racial minorities, or from Asia receiving SGLT2i did not demonstrate a significant reduction in PCO.

CONCLUSIONS

SGLT2i significantly reduce the combined risk of HF hospitalization or cardiovascular mortality among patients with HF and LVEF >40%. However, younger patients, racial minorities, and patients from Asia did not demonstrate such a reduction. Further research is necessary to identify the reasons for such disparities.

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.

Racial and Ethnic Disparities in Stroke Reperfusion Therapy in the USA

Racial and ethnic inequities in stroke care are ubiquitous. Acute reperfusion therapies, i.e., IV thrombolysis (IVT) and mechanical thrombectomy (MT), are central to acute stroke care and are highly efficacious at preventing death and disability after stroke. Disparities in the use of IVT and MT in the USA are pervasive and contribute to worse outcomes among racial and ethnic minority individuals with ischemic stroke. A meticulous understanding of disparities and underlying root causes is necessary in order to develop targeted mitigation strategies with lasting effects. This review details racial and ethnic disparities in the use of IVT and MT after stroke and highlights inequities in the underlying process measures as well as the contributing root causes. Furthermore, this review spotlights the systemic and structural inequities that contribute to race-based differences in the use of IVT and MT, including geographic and regional differences and differences based on neighborhood, zip code, and hospital type. In addition, recent promising trends suggesting improvements in racial and ethnic IVT and MT disparities and potential approaches for future solutions to achieve equity in stroke care are briefly discussed.

Sex Differences in Functional Outcomes Following Endovascular Treatment for Acute Ischemic Stroke

BACKGROUND

Sex disparities have been reported across many aspects of acute ischemic stroke (AIS) care; however, there is a relative paucity of research examining sex differences in outcomes following endovascular treatment (EVT). Some studies report worse functional independence for females following EVT. Few, if any of these studies account for differences in age, baseline function, and comorbidity burden. This retrospective cohort study aimed to assess for sex differences in functional outcomes following EVT by comparing 90-day modified Rankin Scale (mRS) of males and females while controlling for baseline function and comorbidity burden.

METHODS

Baseline demographic and clinical data, and stroke severity were compared for 230 consecutive patients undergoing EVT for AIS between October 2014 and July 2019 at a tertiary stroke centre in Toronto, Canada. Effect of sex on likelihood of functional independence post-EVT was assessed using regression analysis with and without correction for age, baseline mRS, and Charlson Comorbidity Index (CCI).

RESULTS

Females undergoing EVT for AIS were older (75 ± 13 vs. 66 ± 15, p < 0.0001), with worse clinical and functional baselines. Unadjusted, males were more functionally independent (90-day mRS < 3) [OR = 1.831, 95%CI 1.082-3.098]. After controlling for age, baseline mRS and CCI, there was no difference between groups [OR 1.21, 95%CI 0.61-2.37].

CONCLUSIONS

This study provides evidence that prior findings of sex disparities in function after EVT may be accounted for by differences in age, baseline clinical status and functional independence between males and females when a comprehensive measure of comorbidity burden is utilized.

Telehealth Trials to Address Health Equity in Stroke Survivors

Telehealth has seen rapid expansion into chronic care management in the past 3 years because of the COVID-19 pandemic. Telehealth for acute care management has expanded access to equitable stroke care to many patients over the past two decades, but there is limited evidence for its benefit for addressing disparities in the chronic care of patients living with stroke. In this review, we discuss advantages and disadvantages of telehealth use for the outpatient management of stroke survivors. Further, we explore opportunities and potential barriers for telehealth in addressing disparities in stroke outcomes related to various social determinants of health. We discuss two ongoing large randomized trials that are utilizing telehealth and telemonitoring for management of blood pressure in diverse patient populations. Finally, we discuss strategies to address barriers to telehealth use in patients with stroke and in populations with adverse social determinants of health.

Racial disparities in inpatient clinical presentation, treatment, and outcomes in brain metastasis

Background

Few studies have assessed the impact of race on short-term patient outcomes in the brain metastasis population. The goal of this study is to evaluate the association of race with inpatient clinical presentation, treatment, in-hospital complications, and in-hospital mortality rates for patients with brain metastases (BM).

Method

Using data collected from the National Inpatient Sample between 2004 and 2014, we retrospectively identified adult patients with a primary diagnosis of BM. Outcomes included nonroutine discharge, prolonged length of stay (pLOS), in-hospital complications, and mortality.

Results

Minority (Black, Hispanic/other) patients were less likely to receive surgical intervention compared to White patients (odds ratio [OR] 0.70; 95% confidence interval [CI] 0.66-0.74, p < 0.001; OR 0.88; 95% CI 0.84-0.93, p < 0.001). Black patients were more likely to develop an in-hospital complication than White patients (OR 1.35, 95% CI 1.28-1.41, p < 0.001). Additionally, minority patients were more likely to experience pLOS than White patients (OR 1.48; 95% CI 1.41-1.57, p < 0.001; OR 1.34; 95% CI 1.27-1.42, p < 0.001). Black patients were more likely to experience a nonroutine discharge (OR 1.25; 95% CI 1.19-1.31, p < 0.001) and higher in-hospital mortality than White (OR 1.13; 95% CI 1.03-1.23, p = 0.008).

Conclusion

Our analysis demonstrated that race is associated with disparate short-term outcomes in patients with BM. More efforts are needed to address these disparities, provide equitable care, and allow for similar outcomes regardless of care.

Evolution of endovascular stroke centers and disparities in access to stroke care in four Northeastern states: 2015-2019

OBJECTIVES

Disparities exist throughout our healthcare system, especially related to access to care. Advanced stroke care for strokes is only available at selected endovascular centers (ESCs) in the United States. Although the number of ESCs increase each year, this does not necessarily reflect increased access to care. Here, we look at the evolution of ESC in four states and disparities in access to advanced stroke care.

MATERIALS AND METHODS

This is a descriptive study of access to ESCs in four Northeastern states between 2015-2019. Using data from the United States Census Bureau and spatial analysis, we examined the proportion of the population with drive times of less than 60 minutes stratified by income, race/ethnicity, population density, and insurance. We also calculated the mean drive time for each of these socioeconomic groups from their census tracts to the nearest ESC.

RESULTS

Between 2015 and 2019, the number of ESCs increased from 15 to 48. The proportion of patients within a 60-minute drive of an ESC increased from 77% to 88%. However, only 66% of the least densely populated quartile lived within 60 min of an ESC. By income, access to ESCs in the wealthiest quartile was 96.6% compared to 83.7% in the lowest quartile. Hispanics and non-Hispanic Blacks had the largest proportions of populations within 60 minutes of an ESC while Non-Hispanic Whites had the smallest.

CONCLUSIONS

This study underscores the need to evaluate the placement of new ESCs to assure that these hospitals decrease disparities and increase access to advanced stroke care.

Anesthesia, Blood Pressure, and Socioeconomic Status in Endovascular Thrombectomy for Acute Stroke: A Single Center Retrospective Case Cohort

INTRODUCTION

Mechanical thrombectomy (MT) is standard for acute ischemic stroke (AIS), with early studies suggesting that general anesthesia (GA) is associated with worse outcomes than monitored anesthesia care (MAC). Socioeconomic deprivation is also a risk factor for worse AIS outcomes. With improvements in MT and blood pressure (BP) management, it remains unclear if GA or socioeconomic deprivation are risk factors for worse outcomes after MT.

METHODS

We retrospectively analyzed 125 consecutive AIS patients presenting for MT at a comprehensive stroke center serving patients with high levels of socioeconomic deprivation. The primary objective was impact of GA versus MAC on functional independence at 90 days. Secondary outcomes included procedural BP, and impact of BP and socioeconomic deprivation (assessed by the area of deprivation index) on outcomes.

RESULTS

A 90-day outcomes were similar in patients undergoing MT with GA or MAC. The area of deprivation index was similar in GA and MAC groups and in patients with good versus poor 90-day outcomes. There were similar numbers of patients with mean arterial pressure (MAP) <60 mm Hg in the MAC and GA groups (8 vs. 11; P =0.21), but more patients with MAP <70 mm Hg in the GA group (28 vs. 9; P <0.001). Median (interquartile range) duration of MAP <70 mm Hg was 10 (5 to 15) and 20 (10 to 36) minutes in the MAC and GA groups, respectively ( P <0.001); however, these MAPs were not associated with worse 90-day outcomes.

CONCLUSION

Anesthesia and MAP did not affect MT outcomes. The cohort is unique based on an area of deprivation index in the higher deciles in the United States. While the area of deprivation index was not associated with worse outcomes, further study is warranted.

Improving the Prognosis of Patients With Acute Ischemic Stroke Treated in the Late Time Window After the Introduction of Advanced Imaging Software: Benefits From Thrombectomy in the Extended Time Window

BACKGROUND

Mechanical thrombectomy (MT) of ischemic stroke was recommended as a clinical guideline in 2015, and the indication for time was expanded in 2018 based on two clinical studies. We aimed to compare and analyze the prognosis of patients treated under the extended time indication before and after the introduction of advanced software.

METHODS

We obtained data from medical records between 2016 to 2020. From 2016 to 2017, patients who did not receive MT who visited the hospital within 24 hours from the last normal time (LNT) were classified as standard medical treatment (SMT) group. Among patients who underwent MT between 2019 and 2020, patients who visited the hospital between 6-24 hours from the LNT were classified into the extended MT (EMT) group. Good outcome was defined as 3-months modified rankin scale (mRS) ≤ 2, and a poor outcome as mRS ≥ 4.

RESULTS

From 2016 to 2017, 1,058 patients were hospitalized for ischemic stroke, of which 60 (5.7%) received MT, and 27 patients were classified into the SMT group. Among 1,019 patients between 2019 and 2020, 85 (8.3%) received MT, and 24 patients were in the EMT group. Among the SMT group, only 3 had a good prognosis, and 24 (88.9%) had a poor prognosis. However, in the EMT group, 10 (41.7%) had a good prognosis, and 9 (37.5%) had a poor prognosis. The SMT group had a 49.1 times higher risk of poor prognosis compared to the EMT group (P = 0.008).

CONCLUSION

The number of patients with ischemic stroke who receive MT has increased by using advanced imaging software. It was confirmed that patients treated based on the extended time indication also had a good prognosis.

Understanding Delays in MRI-based Selection of Large Vessel Occlusion Stroke Patients for Endovascular Thrombectomy

PURPOSE

Given the efficacy of endovascular thrombectomy (EVT), optimizing systems of delivery is crucial. Magnetic resonance imaging (MRI) is the gold standard for evaluating tissue viability but may require more time to obtain and interpret. We sought to identify determinants of arrival-to-puncture time for patients who underwent MRI-based EVT selection in a real-world setting.

METHODS

Patients were identified from a prospectively maintained database from 2011-2019 that included demographics, presentations, treatments, and outcomes. Process times were obtained from the medical charts. MRI times were obtained from time stamps on the first sequence. Linear and logistic regressions were used to infer explanatory variables of arrival-to-puncture times and effects of arrival-to-puncture time on functional outcomes.

RESULTS

In this study 192 patients (median age 70 years, 57% women, 12% non-white) underwent MRI-based EVT selection. 66% also underwent computed tomography (CT) at the hub before EVT. General anesthesia was used for 33%. Among the entire cohort, the median arrival-to-puncture was 102 min; however, among those without CT it was 77 min. Longer arrival-to-puncture times independently reduced the odds of 90-day good outcome (∆mRS ≤ 2 from pre-stroke, aOR = 0.990, 95%CI = 0.981-0.999, p = 0.040) when controlling for age, NIHSS, and good reperfusion (TICI 2b-3). Independent determinants of longer arrival-to-puncture were CT plus MRI (β = 0.205, p = 0.003), non-white race/ethnicity (β = 0.162, p = 0.012), coronary disease (β = 0.205, p = 0.001), and general anesthesia (β = 0.364, p < 0.0001).

CONCLUSION

Minimizing arrival-to-puncture time is important for outcomes. Real-world challenges exist in an MRI-based EVT selection protocol; avoiding double imaging is key to saving time. Racial/ethnic disparities require further study. Understanding variables associated with delay will inform protocol changes.

Crosstalk between the aging intestinal microflora and the brain in ischemic stroke

Aging is an inevitable phenomenon experienced by animals and humans, and its intensity varies from one individual to another. Aging has been identified as a risk factor for neurodegenerative disorders by influencing the composition of the gut microbiota, microglia activity and cognitive performance. The microbiota-gut-brain axis is a two-way communication path between the gut microbes and the host brain. The aging intestinal microbiota communicates with the brain through secreted metabolites (neurotransmitters), and this phenomenon leads to the destruction of neuronal cells. Numerous external factors, such as living conditions and internal factors related to the age of the host, affect the condition of the intestinal microflora in the form of dysbiosis. Dysbiosis is defined as changes in the composition and function of the gut microflora that affect the pathogenesis, progress, and response to treatment of a disease entity. Dysbiosis occurs when changes in the composition and function of the microbiota exceed the ability of the microflora and its host to restore equilibrium. Dysbiosis leading to dysfunction of the microbiota-gut-brain axis regulates the development and functioning of the host’s nervous, immune, and metabolic systems. Dysbiosis, which causes disturbances in the microbiota-gut-brain axis, is seen with age and with the onset of stroke, and is closely related to the development of risk factors for stroke. The review presents and summarizes the basic elements of the microbiota-gut-brain axis to better understand age-related changes in signaling along the microbiota-gut-brain axis and its dysfunction after stroke. We focused on the relationship between the microbiota-gut-brain axis and aging, emphasizing that all elements of the microbiota-gut-brain axis are subject to age-related changes. We also discuss the interaction between microbiota, microglia and neurons in the aged individuals in the brain after ischemic stroke. Finally, we presented preclinical and clinical studies on the role of the aged microbiota-gut-brain axis in the development of risk factors for stroke and changes in the post-stroke microflora.

SPP1/AnxA1/TIMP1 as Essential Genes Regulate the Inflammatory Response in the Acute Phase of Cerebral Ischemia-Reperfusion in Rats

Background

Ischemic injury in stroke is followed by extensive neurovascular inflammation and changes in ischemic penumbra gene expression patterns. However, the key molecules involved in the inflammatory response during the acute phase of ischemic stroke remain unclear.

Methods

Gene expression profiles of two rat ischemic stroke-related data sets, GSE61616 and GSE97537, were downloaded from the GEO database for Gene Set Enrichment Analysis (GSEA). Then, GEO2R was used to screen differentially expressed genes (DEGs). Furthermore, 170 differentially expressed intersection genes were screened and analyzed for Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment. Candidate genes and miRNAs were obtained by DAVID, Metascape, Cytoscape, STRING, and TargetScan. Finally, the rat middle cerebral artery occlusion-reperfusion (MCAO/R) model was constructed, and qRT-PCR was used to verify the predicted potential miRNA molecule and its target genes.

Results

GO and KEGG analyses showed that 170 genes were highly associated with inflammatory cell activation and cytokine production. After cluster analysis, seven hub genes highly correlated with post-stroke neuroinflammation were obtained: Cxcl1, Kng1, Il6, AnxA1, TIMP1, SPP1, and Ccl6. The results of TargetScan further suggested that miR-340-5p may negatively regulate SPP1, AnxA1, and TIMP1 simultaneously. In the ischemic penumbra of rats 24 h after MCAO/R, the level of miR-340-5p significantly decreased compared with the control group, while the concentration of SPP1, AnxA1, and TIMP1 increased. Time-course studies demonstrated that the mRNA expression levels of SPP1, AnxA1, and TIMP1 fluctuated dramatically throughout the acute phase of cerebral ischemia-reperfusion (I/R).

Conclusion

Our study suggests that differentially expressed genes SPP1, TIMP1, and ANXA1 may play a vital role in the inflammatory response during the acute phase of cerebral ischemia-reperfusion injury. These genes may be negatively regulated by miR-340-5p. Our results may provide new insights into the complex pathophysiological mechanisms of secondary inflammation after stroke.

Toward a Better Understanding of Sex- and Gender-Related Differences in Endovascular Stroke Treatment: A Scientific Statement From the American Heart Association/American Stroke Association

There are many unknowns when it comes to the role of sex in the pathophysiology and management of acute ischemic stroke. This is particularly true for endovascular treatment (EVT). It has only recently been established as standard of care; therefore, data are even more scarce and conflicting compared with other areas of acute stroke. Assessing the role of sex and gender as isolated variables is challenging because they are closely intertwined with each other, as well as with patients' cultural, ethnic, and social backgrounds. Nevertheless, a better understanding of sex- and gender-related differences in EVT is important to develop strategies that can ultimately improve individualized outcome for both men and women. Disregarding patient sex and gender and pursuing a one-size-fits-all strategy may lead to suboptimal or even harmful treatment practices. This scientific statement is meant to outline knowledge gaps and unmet needs for future research on the role of sex and gender in EVT for acute ischemic stroke. It also provides a pragmatic road map for researchers who aim to investigate sex- and gender-related differences in EVT and for clinicians who wish to improve clinical care of their patients undergoing EVT by accounting for sex- and gender-specific factors. Although most EVT studies, including those that form the basis of this scientific statement, report patient sex rather than gender, open questions on gender-specific EVT differences are also discussed.

Aging Microbiota-Gut-Brain Axis in Stroke Risk and Outcome

The microbiota-gut-brain-axis (MGBA) is a bidirectional communication network between gut microbes and their host. Many environmental and host-related factors affect the gut microbiota. Dysbiosis is defined as compositional and functional alterations of the gut microbiota that contribute to the pathogenesis, progression and treatment responses to disease. Dysbiosis occurs when perturbations of microbiota composition and function exceed the ability of microbiota and its host to restore a symbiotic state. Dysbiosis leads to dysfunctional signaling of the MGBA, which regulates the development and the function of the host's immune, metabolic, and nervous systems. Dysbiosis-induced dysfunction of the MGBA is seen with aging and stroke, and is linked to the development of common stroke risk factors such as obesity, diabetes, and atherosclerosis. Changes in the gut microbiota are also seen in response to stroke, and may impair recovery after injury. This review will begin with an overview of the tools used to study the MGBA with a discussion on limitations and potential experimental confounders. Relevant MGBA components are introduced and summarized for a better understanding of age-related changes in MGBA signaling and its dysfunction after stroke. We will then focus on the relationship between the MGBA and aging, highlighting that all components of the MGBA undergo age-related alterations that can be influenced by or even driven by the gut microbiota. In the final section, the current clinical and preclinical evidence for the role of MGBA signaling in the development of stroke risk factors such as obesity, diabetes, hypertension, and frailty are summarized, as well as microbiota changes with stroke in experimental and clinical populations. We conclude by describing the current understanding of microbiota-based therapies for stroke including the use of pre-/pro-biotics and supplementations with bacterial metabolites. Ongoing progress in this new frontier of biomedical sciences will lead to an improved understanding of the MGBA's impact on human health and disease.

Utilizing Implementation Science to Bridge Cerebrovascular Health Disparities: a Local to Global Perspective

PURPOSE OF REVIEW

Stroke is a prime example of a medical disorder whose incidence, prevalence, and outcomes are strongly characterized by health disparities across the globe. This scoping literature review seeks to depict how implementation science could be utilized to advance health equity in the prevention, acute treatment, and post-acute management of stroke in the underserved regions of high-income countries as well as in all low-income countries.

RECENT FINDINGS

A major reason for the persisting and widening cerebrovascular disease disparities is that evidence-based stroke prevention and treatment interventions have been differentially translated (if at all) to various populations and settings. The field of implementation science is endowed with frameworks, theories, methodological approaches, and outcome measures, including equity indices, which could be harnessed to facilitate the translation of evidence-based interventions into clinical practice for underserved and vulnerable communities. Encouragingly, there are several novel frameworks, which eminently merge implementation science constructs with health equity determinants, thereby opening up key opportunities to bridge burgeoning worldwide gaps in cerebrovascular health equity.

The relationship between stroke system organization and disparities in access to stroke center care in California

Background

There are significant racial and ethnic disparities in receipt of reperfusion interventions for acute ischemic stroke. Our objective was to determine whether there are disparities in access to stroke center care by race or ethnicity that help explain differences in reperfusion therapy and to understand whether interhospital patient transfer plays a role in improving access.

Methods

Using statewide administrating data including all emergency department and hospital discharges in California from 2010 to 2017, we identified all acute ischemic stroke patients. Primary outcomes of interest included presentation to primary or comprehensive stroke center (PSC or CSC), interhospital transfer, discharge from PSC or CSC, and discharge from CSC alone. We used hierarchical logistic regression modeling to identify the relationship between patient‐ and hospital‐level characteristics and outcomes of interest.

Results

Of 336,247 ischemic stroke patients, 55.4% were non‐Hispanic White, 19.6% Hispanic, 10.6% non‐Hispanic Asian/Pacific Islander, and 10.3% non‐Hispanic Black. There was no difference in initial presentation to stroke center hospitals between groups. However, adjusted odds of reperfusion intervention, interhospital transfer and discharge from CSC did vary by race and ethnicity. Adjusted odds of interhospital transfer were lower among Hispanic (odds ratio [OR] 0.94, 95% confidence interval [CI] 0.89 to 0.98) and non‐Hispanic Asian/Pacific Islander patients (OR 0.84, 95% CI 0.79 to 0.90) and odds of discharge from a CSC were lower for Hispanic (OR 0.91, 95% CI 0.85 to 0.97) and non‐Hispanic Black patients (OR 0.74, 95% CI 0.67 to 0.81).

Conclusions

There are racial and ethnic disparities in reperfusion intervention receipt among stroke patients in California. Stroke system of care design, hospital resources, and transfer patterns may contribute to this disparity.

Temporal Trends in Racial and Ethnic Disparities in Endovascular Therapy in Acute Ischemic Stroke

Introduction

Endovascular therapy (EVT) use increased following clinical trials publication in 2015, but limited data suggest there may be persistent race and ethnicity differences.

Methods and Results

We included all patients with acute ischemic stroke arriving within 6 hours of last known well and with National Institute of Health Stroke Scale (NIHSS) score ≥6 between April 2012 and June 2019 in the Get With The Guidelines‐Stroke database and evaluated the association between race and ethnicity and EVT use and outcomes, comparing the era before versus after 2015. Of 302 965 potentially eligible patients; 42 422 (14%) underwent EVT. Although EVT use increased over time in all racial and ethnic groups, Black patients had reduced odds of EVT use compared with non‐Hispanic White (NHW) patients (adjusted odds ratio [aOR] before 2015, 0.68 [0.58‒0.78]; aOR after 2015, 0.83 [0.76‒0.90]). In‐hospital mortality/discharge to hospice was less frequent in Black, Hispanic, and Asian patients compared with NHW. Conversely discharge home was more frequent in Hispanic (29.7%; aOR, 1.28 [1.16‒1.42]), Asian (28.2%; aOR, 1.23 [1.05‒1.44]), and Black (29.1%; aOR, 1.08 [1.00‒1.18]) patients compared with NHW (24%). However, at 3 months, functional independence (modified Rankin Scale, 0–2) occurred less frequently in Black (37.5%; aOR, 0.84 [0.75‒0.95]) and Asian (33%; aOR, 0.79 [0.65‒0.98]) patients compared with NHW patients (38.1%).

Conclusions

In a large cohort of patients treated with EVT, Black versus NHW patient disparities in EVT use have narrowed over time but still exist. Discharge related outcomes were slightly more favorable in racial and ethnic underrepresented groups; 3‐month functional outcomes were worse but improved across all groups with time.

Health Equity and Actionable Disparities in Stroke: 2021 Update

There are stark inequities in stroke incidence, prevalence, acute care, rehabilitation, risk factor control, and outcomes. To address these inequities, it is critical to engage communities in identifying priorities and designing, implementing, and disseminating interventions. This issue of Stroke features health equity themed lectures delivered during the International Stroke Conference and Health Equity and Actionable Disparities in Stroke: Understanding and Problem-Solving meetings in 2021 as well as articles covering issues of disparities and diversity in stroke. Bruce Ovbiagele, MD, MSc, MAS, MBA, MLS, received the 2021 William Feinberg Award Lecture for his lifetime achievements in seeking global and local solutions to cerebrovascular health inequities. The second annual Health Equity and Actionable Disparities in Stroke: Understanding and Problem-Solving symposium, which took place the day before the International Stroke Conference in February 2021, focused on community-engaged research for reducing inequities in stroke. Phil Gorelick, MD was awarded the Edgar J. Kenton III Award for his lifetime achievements in using community engagement strategies to recruit and retain Black participants in observational studies and clinical trials. Walter Koroshetz, MD, Director of the National Institute of Neurological Disorders and Stroke delivered the keynote lecture on stroke inequities and Richard Benson, MD, PhD, Director of the Office of Global Health and Health Disparities at National Institute of Neurological Disorders and Stroke, gave a lecture focused on National Institute of Neurological Disorders and Stroke efforts to address inequities. Nichols et al highlighted approaches of community-based participatory research to address stroke inequities. Verma et al showcased digital health innovations to reduce inequities in stroke. Das et al showed that the proportion of underrepresented in medicine vascular neurology fellows has lowered over the past decade and authors provided a road map for enhancing the diversity in vascular neurology. Clearly, to overcome inequities, multipronged strategies are required, from broadening representation among vascular neurology faculty to partnering with communities to conduct research with meaningful impact.

Health Equity: What the Neuroradiologist Needs to Know

Health equity means that everyone has the opportunity to be as healthy as possible, but achieving health equity requires the removal of obstacles to health such as poverty, discrimination, unsafe environments, and lack of access to health care. The pandemic has highlighted the awareness and urgency of delivering patient-centered, high-value care. Disparities in care are antithetical to health equity and have been seen throughout medicine and radiology, including neuroradiology. Health disparities result in low value and costly care that is in conflict with evidence-based medicine, quality standards, and best practices. Although the subject of health equity is often framed as a moral or social justice issue, there are compelling economic arguments that also favor health equity. Not only can waste in health care expenditures be countered but more resources can be devoted to high-value care and other vital national economic interests, including sustainable support for our health system and health providers. There are many opportunities for neuroradiologists to engage in the advancement of health equity, while also advancing the interests of the profession and patient-centered high-value care. Although there is no universal consensus on a definition of health equity, a recent report seeking clarity on the lexicon offered the following conceptual framework: "Health equity means that everyone has a fair and just opportunity to be as healthy as possible. This requires removing obstacles to health such as poverty, discrimination, and their consequences, including powerlessness and lack of access to good jobs with fair pay, quality education and housing, safe environments, and health care."¹ This definition contrasts with that of health disparities that contribute to inequitable care as a result of demographic differences among populations such as those attributable to race, sex, access, residence, socioeconomic status, insurance status, age, religion, and disability.^2,3 In effect, the greater the health disparities and negative social determinants of health, the greater the health inequities will be.

Association of Medicare-Medicaid Dual Eligibility and Race and Ethnicity With Ischemic Stroke Severity

IMPORTANCE

Black and Hispanic US residents are disproportionately affected by stroke incidence, and patients with dual eligibility for Medicare and Medicaid may be predisposed to more severe strokes. Little is known about differences in stroke severity for individuals with dual eligibility, Black individuals, and Hispanic individuals, but understanding hospital admission stroke severity is the first important step for focusing strategies to reduce disparities in stroke care and outcomes.

OBJECTIVE

To examine whether dual eligibility and race and ethnicity are associated with stroke severity in Medicare beneficiaries admitted to acute hospitals with ischemic stroke.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cross-sectional study was conducted using Medicare claims data for patients with ischemic stroke admitted to acute hospitals in the United States from October 1, 2016, to November 30, 2017. Data were analyzed from July 2021 and January 2022.

EXPOSURES

Dual enrollment for Medicare and Medicaid; race and ethnicity categorized as White, Black, Hispanic, and other.

MAIN OUTCOMES AND MEASURES

Claim-based National Institutes of Health Stroke Scale (NIHSS) categorized into minor (0-7), moderate (8-13), moderate to severe (14-21), and severe (22-42) stroke.

RESULTS

Our sample included 45 459 Medicare fee-for-service patients aged 66 and older (mean [SD] age, 80.2 [8.4]; 25 303 [55.7%] female; 7738 [17.0%] dual eligible; 4107 [9.0%] Black; 1719 [3.8%] Hispanic; 37 715 [83.0%] White). In the fully adjusted models, compared with White patients, Black patients (odds ratio [OR], 1.21; 95% CI, 1.06-1.39) and Hispanic patients (OR, 1.54; 95% CI, 1.29-1.85) were more likely to have a severe stroke. Using White patients without dual eligibility as a reference group, White patients with dual eligibility were more likely to have a severe stroke (OR, 1.75; 95% CI, 1.56-1.95). Similarly, Black patients with dual eligibility (OR, 2.15; 95% CI, 1.78-2.60) and Hispanic patients with dual eligibility (OR, 2.50; 95% CI, 1.98-3.16) were more likely to have a severe stroke.

CONCLUSIONS AND RELEVANCE

In this cross-sectional study, Medicare fee-for-service patients with ischemic stroke admitted to acute hospitals who were Black or Hispanic had a higher likelihood of worse stroke severity. Additionally, dual eligibility status had a compounding association with stroke severity regardless of race and ethnicity. An urgent effort is needed to decrease disparities in access to preventive and poststroke care for dual eligible and minority patients.

Underutilization of Endovascular Therapy in Black Patients With Ischemic Stroke: An Analysis of State and Nationwide Cohorts

BACKGROUND AND PURPOSE

Endovascular therapy (EVT) is a very effective treatment but relies on specialized capabilities that are not available in every hospital where acute ischemic stroke is treated. Here, we assess whether access to and utilization of this therapy has extended uniformly across racial and ethnic groups.

METHODS

We conducted a retrospective, population-based study using the 2019 Texas Inpatient Public Use Data File. Acute ischemic stroke cases and EVT use were identified using the International Classification of Diseases, Tenth Revision (ICD-10) diagnosis and procedure codes. We examined EVT utilization by race/ethnicity and performed patient- and hospital-level analyses. To validate state-specific findings, we conducted patient-level analyses using the 2017 National Inpatient Sample for national estimates. To assess independent associations between race/ethnicity and EVT, multivariable modified Poisson regressions were fitted and adjusted relative risks were estimated accounting for patient risk factors and socioeconomic characteristics.

RESULTS

Among 40 814 acute ischemic stroke cases in Texas in 2019, 54% were White, 17% Black, and 21% Hispanic. Black patients had similar admissions to EVT-performing hospitals and greater admissions to comprehensive stroke centers (CSCs) compared with White patients (EVT 62% versus 62%, P=0.21; CSCs 45% versus 39%, P<0.001) but had lower EVT rates (4.1% versus 5.3%; adjusted relative risk, 0.76 [0.66-0.88]; P<0.001). There were no differences in EVT rates between Hispanic and White patients. Lower rates of EVT among Black patients were consistent in the subgroup of patients who arrived in early time windows and received intravenous recombinant tissue-type plasminogen activator (adjusted relative risk, 0.77 [0.61-0.98]; P=0.032) and the subgroup of those admitted to EVT-performing hospitals in both non-CSC (3.0% versus 5.5, P<0.001) and CSC hospitals (7.9% versus 10.4%, P<0.001) while there were no differences between Whites and Hispanic patients. Nationwide sample data confirmed this finding of lower utilization of EVT among Black patients (adjusted relative risk, 0.87 [0.77-0.98]; P=0.024).

CONCLUSIONS

We found no evidence of disparity in presentation to EVT-performing hospitals or CSCs; however, lower rates of EVT were observed in Black patients.

Use of reperfusion therapy and time delay in patients with ischemic stroke by immigration status: a register-based cohort study in Denmark

Background and purpose

Reperfusion therapy is the mainstay of treatment for acute ischaemic stroke (AIS); however, little is known about the use of reperfusion therapy and time delay amongst immigrants.

Methods

This is a Danish nationwide register‐based cohort study of patients with AIS aged ≥18 years (n = 49,817) recruited from 2009 to 2018. Use of reperfusion therapy (intravenous thrombolysis and/or mechanical thrombectomy) and time delay between immigrants and Danish‐born residents were compared using multivariable logistics and quantile regression.

Results

Overall, 10,649 (39.8%) Danish‐born residents and 452 (39.0%) immigrants with AIS were treated with reperfusion therapy in patients arriving <4.5 h following stroke onset. Compared with Danish‐born residents, immigrants had lower odds of receiving reperfusion therapy after adjustment for prehospital delay, age, sex, stroke severity, sociodemographic factors and comorbidities (adjusted odds ratio 0.67; 95% confidence interval 0.49‒0.92, p = 0.01). The lowest odds were observed amongst immigrants originating from Poland and non‐Western countries. Similarly, immigrants had a longer prehospital delay than Danish‐born residents in the fully adjusted model in patients arriving <4.5 h after stroke onset (15 min; 95% confidence interval 4‒26 min, p = 0.03). No evidence was found that system delay and clinical outcome differed between immigrants and Danish‐born residents in patients eligible for reperfusion therapy after adjustment for sociodemographic factors and comorbidities.

Conclusion

Immigration status was significantly associated with lower chances of receiving reperfusion therapy and there may be differences in patient delay between immigrants and Danish‐born residents in patients arriving to a stroke unit <4.5 h after stroke onset.

Racial Disparity in Mechanical Thrombectomy Utilization: Multicenter Registry Results From 2016 to 2020

Background

Previous studies on racial disparity in mechanical thrombectomy (MT) treatment of acute large vessel occlusion stroke lack individual patient data that influence treatment decision‐making. We assessed patient‐level data in a large US health care system from 2016 to 2020 for racial disparities in MT utilization and eligibility.

Methods and Results

A retrospective study was performed of 34 596 patients admitted to 43 hospitals from January 2016 to September 2020. Data included patient age, sex, race, residential zip code median income and population density, presenting hospital stroke certification, baseline ambulation, and National Institutes of Health stroke scale. The cohort included 26 640 White, non‐Hispanic (77.0%), and 7956 African American/Black (23.0%) patients. In multivariable logistic regression, Black patients were less likely to undergo MT (adjusted odds ratio [OR], 0.65; 95% CI, 0.54–0.76), arrive within 5 hours of “last known well” (adjusted OR, 0.73; 95% CI, 0.69–0.78), and have documented anterior circulation large vessel occlusion (adjusted OR, 0.78; 95% CI, 0.64–0.96). Race was not associated with MT rate among patients arriving within 5 hours of last known well with documented acute large vessel occlusion.

Conclusions

Black patients with stroke underwent MT less frequently than White patients, likely in part because of longer times from last known well to hospital arrival and a lower rate of documented acute large vessel occlusion. Further studies are needed to assess whether extending the MT time window and more aggressive large vessel occlusion screening protocols mitigate this disparity.

Evidence-Based Disparities in Stroke Care Metrics and Outcomes in the United States: A Systematic Review

Stroke disproportionately affects racial minorities, and the level to which stroke treatment practices differ across races is understudied. Here, we performed a systematic review of disparities in stroke treatment between racial minorities and White patients. A systematic literature search was performed on PubMed to identify studies published from January 1, 2010, to April 5, 2021 that investigated disparities in access to stroke treatment between racial minorities and White patients. A total of 30 studies were included in the systematic review. White patients were estimated to use emergency medical services at a greater rate (59.8%) than African American (55.6%), Asian (54.7%), and Hispanic patients (53.2%). A greater proportion of White patients (37.4%) were estimated to arrive within 3 hours from onset of stroke symptoms than African American (26.0%) and Hispanic (28.9%) patients. A greater proportion of White patients (2.8%) were estimated to receive tPA (tissue-type plasminogen activator) as compared with African American (2.3%), Hispanic (2.6%), and Asian (2.3%) patients. Rates of utilization of mechanical thrombectomy were also lower in minorities than in the White population. As shown in this review, racial disparities exist at key points along the continuum of stroke care from onset of stroke symptoms to treatment. Beyond patient level factors, these disparities may be attributed to other provider and system level factors within the health care ecosystem.

Striving for Socioeconomic Equity in Ischemic Stroke Care: Imaging and Acute Treatment Utilization From a Comprehensive Stroke Center

PURPOSE

Prior studies have shown socioeconomic disparities in advanced neuroimaging and acute treatment utilization in patients with ischemic stroke. The authors analyzed whether socioeconomic factors were associated with stroke neuroimaging and acute treatment utilization at a comprehensive stroke center.

METHODS

A retrospective study of consecutive acute ischemic stroke discharges from 2012 to 2020 at a comprehensive stroke center was performed. Differences in neuroimaging (CT angiography [CTA], CT perfusion, MRI, and MR angiography [MRA]) and acute treatment (intravenous thrombolysis [IVT] and endovascular thrombectomy [EVT]) utilization were evaluated on the basis of socioeconomic factors of age, sex, race, insurance type, and neighborhood-level median household income. Chi-square tests were used for bivariate analyses. Multivariable logistic regression analyses were performed to determine associations between socioeconomic factors and neuroimaging or treatment utilization while controlling for stroke-specific factors and comorbidities.

RESULTS

Among 6,140 ischemic stroke discharges, race and insurance type were not significantly associated with lower utilization of neuroimaging (CTA, CT perfusion, MRI, and MRA) or acute stroke treatment (IVT and EVT) after controlling for stroke-specific factors and comorbidities. However, median household income < $80,000/year was associated with lower IVT use (odds ratio [OR], 0.74; 95% confidence interval [CI], 0.63-0.87). In addition, age ≥ 80 years had lower CTA (OR, 0.62; 95% CI, 0.51-0.75) and EVT (OR, 0.53; 95% CI, 0.39-0.73) utilization, and female sex had lower CTA (OR, 0.78; 95% CI, 0.65-0.93) utilization. Significantly higher utilization was observed for MRI in Asian (OR, 1.33; 95% CI, 1.04-1.69) and uninsured (OR, 1.64; 95% CI, 1.07-2.50) patients and for MRA (OR, 1.24; 95% CI, 1.04-1.49) and EVT (OR, 1.62; 95% CI, 1.20-2.20) in privately insured patients.

CONCLUSIONS

Once access to a comprehensive stroke center is achieved, socioeconomic disparities in the utilization of health care resources, particularly advanced neuroimaging and acute treatment, may be improved in patients with ischemic stroke.

Mechanical Thrombectomy Access for All? Challenges in Increasing Endovascular Treatment for Acute Ischemic Stroke in the United States

Mechanical thrombectomy (MT) is the most effective treatment for selected patients with an acute ischemic stroke due to emergent large vessel occlusions (LVOs). There is an urgent need to identify and address challenges in access to MT to maximize the numbers of patients who can benefit from this treatment. Barriers in access to MT include delays in evaluation and accurate diagnosis of LVO leading to inappropriate triage, logistical delays related to availability of facilities and trained interventionalists, and financial hurdles that affect treatment reimbursement. Collection of regional data related to these barriers is critical to better understand current access gaps and a measurable access score to thrombectomy could be useful to plan local public health intervention.

The weekend effect on mechanical thrombectomy: A nationwide analysis before and after the pivotal 2015 trials

OBJECTIVES:

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Trauma Communications Center Coordinated Severity-Based Stroke Triage: Protocol of a Hybrid Type 1 Effectiveness-Implementation Study

Background: Mechanical thrombectomy (MT) can improve the outcomes of patients with large vessel occlusion (LVO), but a minority of patients with LVO are treated and there are disparities in timely access to MT. In part, this is because in most regions, including Alabama, the emergency medical service (EMS) transports all patients with suspected stroke, regardless of severity, to the nearest stroke center. Consequently, patients with LVO may experience delayed arrival at stroke centers with MT capability and worse outcomes. Alabama's trauma communications center (TCC) coordinates EMS transport of trauma patients by trauma severity and regional hospital capability. Our aims are to develop a severity-based stroke triage (SBST) care model based on Alabama's trauma system, compare the effectiveness of this care pathway to current stroke triage in Alabama for improving broad, equitable, and timely access to MT, and explore stakeholder perceptions of the intervention's feasibility, appropriateness, and acceptability.

Methods: This is a hybrid type 1 effectiveness-implementation study with a multi-phase mixed methods sequential design and an embedded observational stepped wedge cluster trial. We will extend TCC guided stroke severity assessment to all EMS regions in Alabama; conduct stakeholder interviews and focus groups to aid in development of region and hospital specific prehospital and inter-facility stroke triage plans for patients with suspected LVO; implement a phased rollout of TCC Coordinated SBST across Alabama's six EMS regions; and conduct stakeholder surveys and interviews to assess context-specific perceptions of the intervention. The primary outcome is the change in proportion of prehospital stroke system patients with suspected LVO who are treated with MT before and after implementation of TCC Coordinated SBST. Secondary outcomes include change in broad public health impact before and after implementation and stakeholder perceptions of the intervention's feasibility, appropriateness, and acceptability using a mixed methods approach. With 1200 to 1300 total observations over 36 months, we have 80% power to detect a 15% improvement in the primary endpoint.

Discussion: This project, if successful, can demonstrate how the trauma system infrastructure can serve as the basis for a more integrated and effective system of emergency stroke care.