Differences in stroke subtypes between black and white patients with stroke: the South London Ethnicity and Stroke Study

Racial/ethnic differences in the association of incident stroke with late onset epilepsy: The Northern Manhattan Study

OBJECTIVE

Little is known about the incidence of late onset epilepsy (LOE) across different racial/ethnic groups in the USA, particularly in the Hispanic population. Stroke, a strong predictor of LOE, is more common in non-Hispanic Blacks (NHBs) and Hispanics than in non-Hispanic Whites (NHWs). We assessed the incidence of LOE across racial/ethnic groups and examined whether the associations of stroke with LOE risk differ by race/ethnicity.

METHODS

The Northern Manhattan Study is a population-based longitudinal study of older adults enrolled between 1993 and 2001. Participants free of history of stroke or epilepsy at baseline (n = 3419) were followed prospectively for incidence of LOE. We estimated LOE incidence per 1000 person-years in each racial/ethnic group. We used Cox proportional hazards regression to assess the association of race/ethnicity with LOE and multiplicative interactions of race/ethnicity with incident stroke in relation to LOE, adjusting for demographics and comorbid diagnoses.

RESULTS

During 51 176 person-years of follow-up, 183 individuals developed LOE. Incidence of LOE was significantly higher in NHBs (6.2 per 1000 person-years) than in NHWs (3.3 per 1000 person-years, p = .004). There was no significant difference in LOE incidence between NHWs (3.3 per 1000 person-years) and Hispanics (2.6 per 1000 person-years, p = .875). However, following incident stroke, the risk of LOE differed across racial/ethnic groups. Incident stroke was associated with 2.55 times the risk of LOE among NHWs (95% confidence interval [CI] = .88-7.35), 8.53 times the risk of LOE among Hispanics (95% CI = 5.36-13.57, p = .04 for stronger association than that in NHWs), and 6.46 times the risk of LOE among NHBs (95% CI = 3.79-11.01, p = .12 for stronger association than that in NHWs).

SIGNIFICANCE

We found a stronger association of incident stroke with LOE risk in Hispanics and NHBs than in NHWs, offering some insight into the racial/ethnic disparities of LOE incidence.

Fair prediction of 2-year stroke risk in patients with atrial fibrillation

OBJECTIVE

This study aims to develop machine learning models that provide both accurate and equitable predictions of 2-year stroke risk for patients with atrial fibrillation across diverse racial groups.

MATERIALS AND METHODS

Our study utilized structured electronic health records (EHR) data from the All of Us Research Program. Machine learning models (LightGBM) were utilized to capture the relations between stroke risks and the predictors used by the widely recognized CHADS2 and CHA2DS2-VASc scores. We mitigated the racial disparity by creating a representative tuning set, customizing tuning criteria, and setting binary thresholds separately for subgroups. We constructed a hold-out test set that not only supports temporal validation but also includes a larger proportion of Black/African Americans for fairness validation.

RESULTS

Compared to the original CHADS2 and CHA2DS2-VASc scores, significant improvements were achieved by modeling their predictors using machine learning models (Area Under the Receiver Operating Characteristic curve from near 0.70 to above 0.80). Furthermore, applying our disparity mitigation strategies can effectively enhance model fairness compared to the conventional cross-validation approach.

DISCUSSION

Modeling CHADS2 and CHA2DS2-VASc risk factors with LightGBM and our disparity mitigation strategies achieved decent discriminative performance and excellent fairness performance. In addition, this approach can provide a complete interpretation of each predictor. These highlight its potential utility in clinical practice.

CONCLUSIONS

Our research presents a practical example of addressing clinical challenges through the All of Us Research Program data. The disparity mitigation framework we proposed is adaptable across various models and data modalities, demonstrating broad potential in clinical informatics.

Stroke Demographics, Risk Factors, Subtypes, Syndromes, Mechanisms and Inter-Ethnic Differences between Chinese, Malays and Indians in Singapore-A Hospital-Based Study

Disparities in stroke may be due to socioeconomics, demographics, risk factors (RF) and ethnicity. Asian data are scant. This retrospective hospital-based study aimed to explore demographics, RF, stroke subtypes and mechanisms among the Chinese, Malays and Indians in Singapore. Stroke was subtyped into haemorrhagic stroke (HS) and ischaemic stroke (IS). For IS, the clinical syndrome was classified using the Oxfordshire Community Stroke Project (OCSP) classification while the stroke mechanism was categorised using the Trial of Org 10172 in Acute Stroke Treatment (TOAST) classification. During the study period 1 June 2015 to 31 December 2023, data were collected on 1165 patients, with a mean age of 65.6 ± 12.9 yr; 47.4% were female, 83% were Chinese and hypertension (63.5%) and hyperlipidaemia (60.3%) were the most common RF. HS comprised 23.5% (95%CI 21.1-26.1%) (intracerebral 21.7%, subarachnoid 1.3%) of the patients, while IS comprised 76.5% (95%CI 73.9-78.9%) (small artery occlusion 29.0%, cardioembolism 13.3%, large artery atherosclerosis 9.4%, stroke of other determined aetiology 6.2%, stroke of undetermined aetiology 18.6%); 55% of patients had lacunar syndrome. A multivariable analysis showed that HS was associated with ethnicity (p = 0.044), diabetes mellitus (OR 0.27, 95%CI 0.18-0.41, p < 0.001) and smoking (OR 0.47, 95%CI 0.34-0.64, p < 0.001). There were no significant inter-ethnic differences by the OCSP (p = 0.31) or TOAST (p = 0.103) classification. While differences in stroke subtype in Asia may be due to RF, ethnicity has a role. More studies are needed to further explore this.

Does Thrombosis Play a Causal Role in Lacunar Stroke and Cerebral Small Vessel Disease?

BACKGROUND

The importance of thromboembolism in the pathogenesis of lacunar stroke (LS), resulting from cerebral small vessel disease (cSVD), is debated, and although antiplatelets are widely used in secondary prevention after LS, there is limited trial evidence from well-subtyped patients to support this approach. We sought to evaluate whether altered anticoagulation plays a causal role in LS and cSVD using 2-sample Mendelian randomization.

METHODS

From a recent genome-wide association study (n=81 190), we used 119 genetic variants associated with venous thrombosis at genome-wide significance (P<5*10-8) and with a linkage disequilibrium r2<0.001 as instrumental variables. We also used genetic associations with stroke from the GIGASTROKE consortium (62 100 ischemic stroke cases: 10 804 cardioembolic stroke, 6399 large-artery stroke, and 6811 LS). In view of the lower specificity for LS with the CT-based phenotyping mainly used in GIGASTROKE, we also used data from patients with magnetic resonance imaging-confirmed LS (n=3199). We also investigated associations with more chronic magnetic resonance imaging features of cSVD, namely, white matter hyperintensities (n=37 355) and diffusion tensor imaging metrics (n=36 533).

RESULTS

Mendelian randomization analyses showed that genetic predisposition to venous thrombosis was associated with an increased odds of any ischemic stroke (odds ratio [OR], 1.19 [95% CI, 1.13-1.26]), cardioembolic stroke (OR, 1.32 [95% CI, 1.21-1.45]), and large-artery stroke (OR, 1.41 [95% CI, 1.26-1.57]) but not with LS (OR, 1.07 [95% CI, 0.99-1.17]) in GIGASTROKE. Similar results were found for magnetic resonance imaging-confirmed LS (OR, 0.94 [95% CI, 0.81-1.09]). Genetically predicted risk of venous thrombosis was not associated with imaging markers of cSVD.

CONCLUSIONS

These findings suggest that altered thrombosis plays a role in the risk of cardioembolic and large-artery stroke but is not a causal risk factor for LS or imaging markers of cSVD. This raises the possibility that antithrombotic medication may be less effective in cSVD and underscores the necessity for further trials in well-subtyped cohorts with LS to evaluate the efficacy of different antithrombotic regimens in LS.

Carotid Intima-Media Thickness and Improved Stroke Risk Assessment in Hypertensive Black Adults

BACKGROUND

We aim to determine the added value of carotid intima-media thickness (cIMT) in stroke risk assessment for hypertensive Black adults.

METHODS

We examined 1,647 participants with hypertension without a history of cardiovascular (CV) disease, from the Jackson Heart Study. Cox regression analysis estimated hazard ratios (HRs) for incident stroke per standard deviation increase in cIMT and quartiles while adjusting for baseline variables. We then evaluated the predictive capacity of cIMT when added to the pool cohort equations (PCEs).

RESULTS

The mean age at baseline was 57 ± 10 years. Each standard deviation increase in cIMT (0.17 mm) was associated with approximately 30% higher risk of stroke (HR 1.27, 95% confidence interval: 1.08-1.49). Notably, cIMT proved valuable in identifying residual stroke risk among participants with well-controlled blood pressure, showing up to a 56% increase in the odds of stroke for each 0.17 mm increase in cIMT among those with systolic blood pressure <120 mm Hg. Additionally, the addition of cIMT to the PCE resulted in the reclassification of 58% of low to borderline risk participants with stroke to a higher-risk category and 28% without stroke to a lower-risk category, leading to a significant net reclassification improvement of 0.22 (0.10-0.30).

CONCLUSIONS

In this community-based cohort of middle-aged Black adults with hypertension and no history of CV disease at baseline, cIMT is significantly associated with incident stroke and enhances stroke risk stratification.

Salt Sensitivity of Blood Pressure in Black People: The Need to Sort Out Ancestry Versus Epigenetic Versus Social Determinants of Its Causation

Race is a social construct, but self-identified Black people are known to have higher prevalence and worse outcomes of hypertension than White people. This may be partly due to the disproportionate incidence of salt sensitivity of blood pressure in Black people, a cardiovascular risk factor that is independent of blood pressure and has no proven therapy. We review the multiple physiological systems involved in regulation of blood pressure, discuss what, if anything is known about the differences between Black and White people in these systems and how they affect salt sensitivity of blood pressure. The contributions of genetics, epigenetics, environment, and social determinants of health are briefly touched on, with the hope of stimulating further work in the field.

Looking Upstream to Understand Race/Ethnicity as a Moderator for Poststroke Neuroinflammation and a Social Determinant for Poststroke Aphasia Outcomes

INTRODUCTION

Over the past decade, the stroke literature has begun to acknowledge and explore explanations for longstanding racial/ethnic differences in stroke outcomes. Poststroke cognitive impairment (PSCI) and poststroke aphasia are two such negative poststroke outcomes where racial/ethnic differences exist. Physiological differences, such as stroke type and lesion size, have been used to partially explain the variation in PSCI and aphasia. However, there is some evidence, although limited, that suggests neuroinflammatory processes as part of allostatic load may be a key contributor to the observed disparities.

METHOD

In this tutorial, we explore the influence of race differences in inflammation on poststroke cognitive outcomes. We suggest lifetime stress and other external determinants of health such as neighborhood environment and discriminatory practices through "weathering" explain differences in inflammation. While using an allostatic load framework, we explore the literature focusing specifically on the role of neuroinflammation on poststroke outcomes.

CONCLUSIONS

Examination of the immune response poststroke provides a foundation for understanding the mechanisms of PSCI and poststroke aphasia and the potential contributions of neuroinflammatory processes on poststroke cognitive outcomes. Furthermore, understanding of racial differences in those processes may contribute to a better understanding of racial disparities in general stroke outcomes as well as poststroke aphasia.

Racial and Ethnic Disparities in Stroke Prevention for Atrial Fibrillation

Racial and ethnic disparities in health care are well documented, although often underappreciated. In the setting of atrial fibrillation, stroke risk and severity may be higher in underrepresented ethnic populations. Additionally, the risk of bleeding is not uniform, and pharmacogenetics play an important role in anticoagulant therapy. In this narrative review, we discuss the complex issues surrounding stroke prevention in underrepresented ethnic groups with atrial fibrillation.

Ethnodemographic characterization of stroke incidence and burden of disease in hospital discharge records in Ecuador

Introduction

Stroke is the second most common cause of death and disability-adjusted life years (DALYs) globally. However, the incidence and impact of stroke by ethnicity and gender is frequently distinct. This is particularly the case in Ecuador where geographic and economic marginalization are often correlated with ethnic marginalization and the extent to which females lack the same opportunities as their male counterparts. The aim of this paper is to investigate the differential impacts in terms of stroke diagnosis and burden of disease by ethnicity and gender, using hospital discharge records over the years 2015-2020.

Methods

This paper calculates stroke incidence, and fatality rates using hospital discharge and death records over the years 2015-2020. The DALY package in R was employed to calculate the Disability Adjusted Life Years lost due to stroke in Ecuador.

Results

The results show that while the incidence rate of stroke in males (64.96 per 100,000 persons-year) is higher than that for females on average (57.84 per 100,000 persons-year), males accounted for 52.41% of all stroke cases and 53% of all surviving cases. Thus, hospital data suggests that females had a higher death rate when compared to males. Case fatality rates also differed significantly by ethnicity. The highest fatality rate corresponded to the Montubio ethnic group (87.65%), followed by Afrodescendants (67.21%). The estimated burden of disease of stroke calculated using Ecuadorian hospital records (2015-2020) varied from 1,468 to 2,991 DALY per 1,000 population on average.

Discussion

Differences in the burden of disease by ethnic group are likely to reflect differential access to care by region and socio-economic group, both of which are frequently correlated with ethnic composition in Ecuador. Equitable access to health services remains an important challenge in the country. The gender discrepancy in fatality rates suggests that there is a need for targeted educational campaigns to identify stroke signs early, especially in the female population.

Promise of Physiological Profiling to Prevent Stroke in People of African Ancestry: Prototyping Ghana

PURPOSE OF REVIEW

Worldwide, compared to other racial/ethnic groups, individuals of African ancestry have an excessively higher burden of hypertension-related morbidities, especially stroke. Identifying modifiable biological targets that contribute to these disparities could improve global stroke outcomes. In this scoping review, we discuss how pathological perturbations in the renin-angiotensin-aldosterone pathways could be harnessed via physiological profiling for the purposes of improving blood pressure control for stroke prevention among people of African ancestry.

RECENT FINDINGS

Transcontinental comparative data from the USA and Ghana show that the prevalence of treatment-resistant hypertension among stroke survivors is 42.7% among indigenous Africans, 16.1% among African Americans, and 6.9% among non-Hispanic Whites, p < 0.0001. A multicenter clinical trial of patients without stroke in 3 African countries (Nigeria, Kenya, and South Africa) demonstrated that physiological profiling using plasma renin activity and aldosterone to individualize selection of antihypertensive medications compared with usual care resulted in better blood pressure control with fewer medications over 12 months. Among Ghanaian ischemic stroke survivors treated without renin-aldosterone profiling data, an analysis revealed that those with low renin phenotypes did not achieve any meaningful reduction in blood pressure over 12 months on 3-4 antihypertensive medications despite excellent adherence. For a polygenic condition such as hypertension, individualized therapy based on plasma renin-aldosterone-guided selection of therapy for uncontrolled BP following precision medicine principles may be a viable strategy for primary and secondary stroke prevention with the potential to reduce disparities in the poor outcomes of stroke disproportionately shared by individuals of African ancestry. A dedicated clinical trial to test this hypothesis is warranted.

Evaluation of the Rapid Arterial oCclusion Evaluation (RACE) scale in Upstate South Carolina, USA

OBJECTIVES

Several stroke assessments have been designed for Emergency Medical Services to identify stroke patients with large vessel occlusion in the prehospital setting. The Rapid Arterial oCclusion Evaluation scale was developed in Spain, yet only few United States-based studies have confirmed findings from Spain. This study was designed to determine if the Rapid Arterial oCclusion Evaluation scale is a valid prehospital stroke assessment for identifying large vessel occlusion patients in South Carolina, USA.

MATERIALS AND METHODS

The performance of the Rapid Arterial oCclusion Evaluation scale was determined by calculating the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy at each score. The discriminative power of the Rapid Arterial oCclusion Evaluation score was evaluated using receiver operator characteristics. Comparison of the Rapid Arterial oCclusion Evaluation Scale to the National Institute of Health Stroke Scale was assessed using the Spearman's coefficient.

RESULTS

The Rapid Arterial oCclusion Evaluation scale had an acceptable discriminative power (c = 0.71). A score of ≥5 had a sensitivity of 0.71, specificity of 0.65, positive predictive value of 0.24, negative predictive value of 0.93, and accuracy of 0.66. There was a significant correlation between the Rapid Arterial Cclusion Evaluation score and the National Institute of Health Stroke Scale (rho = 0.60).

CONCLUSION

The Rapid Arterial oCclusion Evaluation scale performed comparably to the National Institute of Health Stroke Scale in South Carolina; however, performed lower than Spain. Future studies should investigate patient demographics and emergency medical services training to determine if these variables contribute to the results found in this study.

Polygenic Risk, Midlife Life's Simple 7, and Lifetime Risk of Stroke

Background

Recent genetic discoveries in stroke have unleashed the potential of using genetic information for risk prediction and health interventions aimed at disease prevention. We sought to estimate the lifetime risk of stroke (LTRS) by levels of genetic risk and to investigate whether optimal cardiovascular health can offset the negative impact of high genetic risk on lifetime risk of stroke.

Methods and Results

Study participants were 11 568 middle‐aged adults (56% women, 23% Black adults), who were free of stroke at baseline and were followed up for a median of 28 years. The remaining LTRS was estimated according to levels of genetic risk based on a validated stroke polygenic risk score, and to levels of cardiovascular health based on the American Heart Association Life's Simple 7 recommendations. At age 45, individuals with high, intermediate, and low polygenic risk score had a remaining LTRS of 23.2% (95% CI, 20.8%–25.5%), 13.8% (95% CI, 11.7%–15.8%), and 9.6% (95% CI, 7.3%–11.8%), respectively. Those with both a high genetic risk and an inadequate Life's Simple 7 experienced the highest LTRS: 24.8% (95% CI, 22.0%–27.6%). Across all polygenic risk score categories, those with an optimal Life's Simple 7 had a ≈30% to 43% lower LTRS than those with an inadequate Life's Simple 7. This corresponded to almost 6 additional years lived free of stroke.

Conclusions

The LTRS varies by levels of polygenic risk and cardiovascular health. Maintaining an optimal cardiovascular health can partially offset a high genetic risk, emphasizing the importance of modifiable risk factors and illustrating the potential of personalizing genetic risk information to motivate lifestyle changes for stroke prevention.

Apparent Treatment-Resistant Hypertension Among Stroke Survivors: A Transcontinental Study Assessing Impact of Race and Geography

BACKGROUND

Race and geographic differences in the prevalence and predictors of hypertension in stroke survivors have been reported, but apparent treatment-resistant hypertension (aTRH) among stroke survivors by race (African ancestry vs. non-Hispanic Caucasians) and by geography (continental Africa vs. the United States) are under studied.

METHODS

This is a cross-sectional study using ethically approved stroke registries from the University of Florida and the Kwame Nkrumah University of Science and Technology, Kumasi, Ghana. Univariate and multivariate regression was used to evaluate for differences in prevalence of aTRH and associations with clinical covariates.

RESULTS

Harmonized data were available for 3,365 stroke survivors of which 943 (28.0%) were indigenous Africans, 558 (16.6%) African Americans, and 1,864 (55.4%) non-Hispanic Caucasians with median ages (interquartile range) of 59 (49-68), 61 (55-72), and 70 (62-78) years, P < 0.0001. The overall frequency of aTRH was 18.5% (95% confidence interval [CI]: 17.2%-19.8%) with 42.7% (95% CI: 39.6%-46.0%) among indigenous Africans, 16.1% (95% CI: 13.2%-19.5%) among African Americans, and 6.9% (95% CI: 5.8%-8.2%) among non-Hispanic Caucasians, P < 0.0001. Five factors associated with aTRH: age, adjusted odds ratio (95% CI) of 0.99 (0.98-0.99), female sex 0.70 (0.56-0.87), cigarette smoking 1.98 (1.36-2.90), intracerebral hemorrhage 1.98 (1.57-2.48), and Black race namely indigenous Africans 4.42 (3.41-5.73) and African Americans 2.44 (1.81-3.29).

CONCLUSIONS

Future studies are needed to investigate the contribution of socioeconomic disparities in the prevalence aTRH in those with African Ancestry to explore the long-term impact, and evaluate effective therapeutic interventions in this subpopulation.

Incidence of stroke, transient ischaemic attack and determinants of poststroke mortality among immigrants in Denmark, 2004‒2018: a population-based cohort study

OBJECTIVE

Using recent registry data, we aimed to quantify the incidence of stroke and transient ischaemic attack (TIA) and to examine factors influencing the risk of poststroke mortality among immigrants compared with Danish-born individuals.

DESIGN

Population-based cohort study between 2004 and 2018. We estimated age-standardised incidence rate ratios (IRR) of stroke, stroke types and TIA for each ethnic group using Danish-born individuals as the reference by direct method of standardisation. We calculated the risk of poststroke mortality using Cox proportional hazard regression.

SETTING

The study was conducted using Danish nationwide registers.

PARTICIPANTS

All cases of first-ever stroke and TIA by country of origin (n=132 936) were included.

RESULTS

Overall, Western immigrants (IRR=2.25; 95% CI 2.20 to 2.31) and non-Western immigrants (IRR=1.37; 95% CI 1.30 to 1.44) had a higher risk of stroke than Danish-born individuals. The risk of TIA was higher in Western immigrants (IRR=2.08; 95% CI 1.93 to 2.23) followed by non-Western immigrants (IRR=1.45; 95% CI 1.27 to 1.63) than in Danish-born individuals. All-cause 1-year mortality hazard was higher but not significantly different in non-Western men (adjusted HR=1.38; 95% CI 0.92 to 2.08) compared with Danish-born men and additional adjustment for comorbidities reduced the HR to 0.85 (0.51 to 1.40) among ischaemic stroke cases. Among intracerebral haemorrhage cases, the adjusted mortality hazard was decreased in Western men (from HR of 1.76; 95% CI 1.09 to 2.85 to HR of 1.30; 95% CI 0.80 to 2.11) compared with Danish-born men after adjustment for stroke severity. Immigrants with ≤15 years of residence had a lower poststroke mortality hazard than Danish-born individuals after additional adjustment for sociodemographic factors (HR=0.36; 95% CI 0.14 to 0.91).

CONCLUSIONS

The age-standardised risk of stroke and TIA was significantly higher among the majority of immigrants than Danish-born individuals. Interventions that reduce the burden of comorbidities, improve acute stroke care and target sociodemographic factors may address the higher risk of poststroke mortality among immigrants.

Elastin-Derived Peptides in the Central Nervous System: Friend or Foe

Elastin is one of the main structural matrix proteins of the arteries, lung, cartilage, elastic ligaments, brain vessels, and skin. These elastin fibers display incredible resilience and structural stability with long half-life. However, during some physiological and pathophysiological conditions, elastin is prone to proteolytic degradation and, due to the extremely low turnover rate, its degradation is practically an irreversible and irreparable phenomenon. As a result of elastin degradation, new peptides called elastin-derived peptides (EDPs) are formed. A growing body of evidence suggests that these peptides play an important role in the development of age-related vascular disease. They are also detected in the cerebrospinal fluid of healthy people, and their amount increases in patients after ischemic stroke. Recently, elastin-like polypeptides have been reported to induce overproduction of beta-amyloid in a model of Alzheimer's disease. Nevertheless, the role and mechanism of action of EDPs in the nervous system is largely unknown and limited to only a few studies. The article summarizes the current state of knowledge on the role of EDPs in the nervous system.

Race Differences in High-Grade Carotid Artery Stenosis

Background and Purpose

Despite a higher incidence of stroke and a more adverse cardiovascular risk factor profile in Blacks and Hispanics compared with Whites, carotid artery revascularization is performed less frequently among these subpopulations. We assessed racial differences in high-grade (≥70% diameter-reducing) carotid stenosis.

Methods

Consecutive clients in a Nationwide Life Line for-Profit Service to screen for vascular disease, 2005 to 2019 were evaluated in a cross-sectional study. The prevalence of high-grade stenosis, defined by a carotid ultrasound peak systolic velocity of ≥230 cm/s, was assessed. Participants self-identified as White, Black, Hispanic, Asian, Native American, or other. Race/ethnic differences were assessed using Poisson regression. The number of individuals in the United States with high-grade stenosis was estimated by applying prevalence estimates to 2015 US Census population estimates.

Results

The prevalence of high-grade carotid stenosis was estimated in 6 130 481 individuals. The prevalence of high-grade stenosis was higher with increasing age in all race-sex strata. Generally, Blacks and Hispanics had a lower prevalence of high-grade stenosis compared with Whites, while Native Americans had a higher prevalence. For example, for men aged 55 to 65, the relative risk of stenosis compared with Whites was 0.40 (95% CI, 0.29–0.55) and 0.61 (95% CI, 0.46–0.81) for Blacks and Hispanics, respectively; and 1.53 (95% CI, 1.12–2.10) for Native Americans. When these prevalence estimates were applied to the Census estimates of the US population, an estimated 327 721 individuals have high-grade stenosis, of whom 7% are Black, 7% Hispanic, and 43% women.

Conclusions

Despite their having a more adverse cardiovascular risk profile, there was a lower prevalence of high-grade carotid artery stenosis for both the Black and Hispanic relative to the White clients. This lower prevalence of high-grade stenosis is a potential contributor to the lower use of carotid revascularization procedures in these minority populations.

Genetic basis of lacunar stroke: a pooled analysis of individual patient data and genome-wide association studies

BACKGROUND

The genetic basis of lacunar stroke is poorly understood, with a single locus on 16q24 identified to date. We sought to identify novel associations and provide mechanistic insights into the disease.

METHODS

We did a pooled analysis of data from newly recruited patients with an MRI-confirmed diagnosis of lacunar stroke and existing genome-wide association studies (GWAS). Patients were recruited from hospitals in the UK as part of the UK DNA Lacunar Stroke studies 1 and 2 and from collaborators within the International Stroke Genetics Consortium. Cases and controls were stratified by ancestry and two meta-analyses were done: a European ancestry analysis, and a transethnic analysis that included all ancestry groups. We also did a multi-trait analysis of GWAS, in a joint analysis with a study of cerebral white matter hyperintensities (an aetiologically related radiological trait), to find additional genetic associations. We did a transcriptome-wide association study (TWAS) to detect genes for which expression is associated with lacunar stroke; identified significantly enriched pathways using multi-marker analysis of genomic annotation; and evaluated cardiovascular risk factors causally associated with the disease using mendelian randomisation.

FINDINGS

Our meta-analysis comprised studies from Europe, the USA, and Australia, including 7338 cases and 254 798 controls, of which 2987 cases (matched with 29 540 controls) were confirmed using MRI. Five loci (ICA1L-WDR12-CARF-NBEAL1, ULK4, SPI1-SLC39A13-PSMC3-RAPSN, ZCCHC14, ZBTB14-EPB41L3) were found to be associated with lacunar stroke in the European or transethnic meta-analyses. A further seven loci (SLC25A44-PMF1-BGLAP, LOX-ZNF474-LOC100505841, FOXF2-FOXQ1, VTA1-GPR126, SH3PXD2A, HTRA1-ARMS2, COL4A2) were found to be associated in the multi-trait analysis with cerebral white matter hyperintensities (n=42 310). Two of the identified loci contain genes (COL4A2 and HTRA1) that are involved in monogenic lacunar stroke. The TWAS identified associations between the expression of six genes (SCL25A44, ULK4, CARF, FAM117B, ICA1L, NBEAL1) and lacunar stroke. Pathway analyses implicated disruption of the extracellular matrix, phosphatidylinositol 5 phosphate binding, and roundabout binding (false discovery rate <0·05). Mendelian randomisation analyses identified positive associations of elevated blood pressure, history of smoking, and type 2 diabetes with lacunar stroke.

INTERPRETATION

Lacunar stroke has a substantial heritable component, with 12 loci now identified that could represent future treatment targets. These loci provide insights into lacunar stroke pathogenesis, highlighting disruption of the vascular extracellular matrix (COL4A2, LOX, SH3PXD2A, GPR126, HTRA1), pericyte differentiation (FOXF2, GPR126), TGF-β signalling (HTRA1), and myelination (ULK4, GPR126) in disease risk.

FUNDING

British Heart Foundation.

Race/Ethnic and Stroke Subtype Differences in Poststroke Functional Recovery After Acute Rehabilitation

OBJECTIVE

Significant racial/ethnic disparities in poststroke function exist, but whether these disparities vary by stroke subtype is unknown. Study goals were to (1) determine if racial/ethnic disparities in the recovery of poststroke function varied by stroke subtype and (2) identify confounding factors associated with these racial/ethnic disparities.

DESIGN

Secondary analysis of the 1-year Stroke Recovery in Underserved Populations Cohort Study.

SETTING

Eleven inpatient rehabilitation facilities (IRFs) across the United States.

PARTICIPANTS

A total of 1066 patients (n=868 with ischemic stroke and n=198 with hemorrhagic stroke, N=1066) who self-identified as White (n=813), Black (n=183), or Hispanic (n=70).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

FIM scores at IRF admission, discharge, 3 months, and 12 months were modeled using multivariable mixed effects longitudinal regression.

RESULTS

Compared with White patients, Black (-6.1 and -4.6) and Hispanic (-10.1 and -9.9) patients had significantly lower FIM scores at 3 and 12 months, respectively. A significant (P<.01) 3-way interaction (race/ethnic*subtype*time) indicated that disparities varied by stroke subtype. The stroke subtype differences were most prominent for Black-White disparities because disparities in hemorrhagic stroke were present at IRF admission (vs 3 months for ischemic stroke). Additionally, at 12 months, the magnitude of Black-White disparities was over 3 times larger for hemorrhagic stroke (-10.4) than ischemic stroke (-3.1). Age primarily influenced Black-White disparities (especially for hemorrhagic stroke), but factors that influenced Hispanic-White disparities were not identified. Sensitivity analyses showed that there were stroke subtype differences in racial/ethnic disparities for cognitive (but not motor) function, and results were robust to adjustments for missing data because of attrition.

CONCLUSIONS

There are significant differences between stroke subtypes in the timing and magnitude of Black-White disparities in poststroke function. Age was a major confounding factor for Black-White disparities (particularly for hemorrhagic stroke). Overall, Hispanic patients had the lowest levels of poststroke function, and more work is needed to identify significant factors that influence Hispanic-White disparities.

Immigration Status, Ethnicity, and Long-term Outcomes Following Ischemic Stroke

OBJECTIVE

To assess the association between immigration status and ethnicity and the outcomes of mortality and vascular event recurrence following ischemic stroke in Ontario, Canada.

METHODS

We conducted a retrospective cohort study using linked administrative and clinical registry-based data from 2002 to 2018 and compared hazards of all-cause mortality and vascular event recurrence in immigrants and long-term residents using inverse probability of treatment weighting accounting for age, sex, income, and comorbidities. We stratified analyses by age (≤75 and >75 years) and used interaction terms to evaluate whether the association between immigration status and outcomes varied with age or ethnicity.

RESULTS

We followed 31,918 adult patients, of whom 2,740 (8.6%) were immigrants, for a median follow-up of 5 years. Immigrants had lower mortality than long-term residents (46.1% vs 64.5%), which was attenuated after adjustment (hazard ratio [HR] 0.94; 95% confidence interval [CI] 0.88-1.00), but persisted in those younger than 75 years (HR 0.82; 0.74-0.91). Compared to their respective ethnic long-term resident counterparts, the adjusted hazard of death was higher in South Asian immigrants, similar in Chinese immigrants, and lower in other immigrants (p value for interaction = 0.003). The adjusted hazard of vascular event recurrence (HR 1.01; 0.92-1.11) was similar in immigrants and long-term residents, and this observation persisted across all age and ethnic groups.

CONCLUSIONS

Long-term mortality following ischemic stroke is lower in immigrants than in long-term residents, but is similar after adjustment for baseline characteristics, and it is modified by age at the time of stroke and by ethnicity.

Adherence to Antithrombotic Treatment and Ischemic Stroke Recurrence in Egypt and Germany: A Comparative Analysis

BACKGROUND

The burden of stroke weighs heavily in developing countries where recurrence rates clearly exceed that of developed countries. The impact of nonadherence to antithrombotic treatment within this context has been poorly investigated.

OBJECTIVE

The objective of this study was to evaluate patients with recurrent ischemic stroke in Egypt and Germany with focus on stroke subtype distribution and adherence to antithrombotic therapy.

METHODS

We conducted a comparative cross-sectional retrospective cohort study enrolling consecutive patients hospitalized for recurrent ischemic stroke in 2017 in 2 academic centers. Data were collected on demographics, risk factors, stroke subtypes, and medication adherence. Nonadherence to antithrombotic agents was analyzed at the time point of index stroke (recurrent stroke). Predictors of nonadherence were analyzed using logistic regression.

RESULTS

A total of 373 Egyptian and 468 German patients with ischemic stroke were included. The proportion of recurrent ischemic stroke among all patients was higher in the Egyptian cohort compared to the German cohort (33 vs. 10%, p < 0.05). Small-vessel occlusion stroke was the most frequent subtype in Egyptians, with a significantly greater proportion than in Germans (45 vs. 26%, p < 0.05). Nonadherence to antiplatelets at the time point of the recurrent stroke was higher in Egyptians than in Germans (82 vs. 19%, p < 0.001). Low educational attainment among Egyptians (OR 0.14, 95% CI [0.00-0.19], p < 0.01) and high comorbidity scores among Germans (OR 2.45, 95% CI [1.06-5.66], p < 0.05) were found to be predictors of nonadherence to antithrombotic treatment.

CONCLUSIONS

The large stroke recurrence burden in Egypt may be partly explained by differing adherence to secondary preventative antithrombotic pharmacotherapy. Predictors of medication nonadherence have to be addressed to reduce stroke recurrence disparities.

Frequency and factors linked to refractory hypertension among stroke survivors in Ghana

BACKGROUND

Refractory hypertension (RfH) is a rare, severe phenotype of resistant hypertension, linked to higher risk of adverse cardiovascular outcomes. Little is known about the association of RfH with stroke type and subtype.

OBJECTIVE

To determine the prevalence and predictors of RfH among stroke survivors in Ghana.

METHODS

We interrogated the dataset of a prospectively collected registry of hypertensive patients seen between July 2015 and June 2019, at five hospitals in Ghana. We compared stroke survivors to stroke-free controls. Clinic-based blood pressure was measured using a standardized protocol and antihypertensive medications were assessed via review of medical records and inspection of pills. Refractory hypertension was defined as office BP ≥140/90 mmHg on ≥5 classes of antihypertensive medications. Multivariate logistic regression models were constructed to assess factors associated with RfH.

RESULTS

Of 3927 hypertensive patients (1169 stroke survivors, 2758 controls), 86 had RfH for an overall prevalence of 2.2% (95% CI: 1.8-2.7%). Among patients with RfH, 5.8% (4.5-7.3%) were stroke survivors vs. 0.7% (0.4-1.0%) were stroke-free (p < .0001). Adjusted odds ratio (95% CI) for factors associated with RfH were being male (1.81, 1.15-2.85), age < 60 years (2.64, 1.59-4.40), chronic kidney disease (2.09, 1.21-3.60), and known stroke (7.53, 4.35-13.04). RfH was associated with intracerebral hemorrhage, (11.43, 5.65-23.14), ischemic stroke (9.76, 5.47-17.42), lacunar stroke (13.58, 6.45-28.61), and non-lacunar ischemic stroke (3.67, 1.04-13.02).

CONCLUSION

Presence of RfH is significantly accentuated among stroke survivors. Intensified efforts are warranted to identify and aggressively address barriers to control in these patients to avert subsequent vascular events.

Association Between Immigration Status and Acute Stroke Care

Background and Purpose—

Immigrants to high-income countries have a lower incidence of stroke compared with long-term residents; however, little is known about the care and outcomes of stroke in immigrants.

Methods—

We used linked clinical and administrative data to conduct a retrospective cohort study of adults seen in the emergency department or hospitalized with ischemic stroke or transient ischemic attack between July 1, 2003, and April 1, 2013, and included in the provincial stroke registry. We ascertained immigration status using immigration records and compared processes of stroke care delivery between immigrants (defined as those immigrating after 1985) and long-term residents. In the subgroup with ischemic stroke, we calculated inverse probability treatment weight (IPTW)–adjusted risk ratios for disability on discharge (modified Rankin Scale score of 3 to 5), accounting for demographic characteristics and comorbid conditions to compare outcomes between immigrants and long-term residents.

Results—

We included 34 987 patients with ischemic stroke or transient ischemic attack, of whom 2649 (7.6%) were immigrants. Immigrants were younger than long-term residents at the time of stroke/transient ischemic attack (median age 67 years versus 76 years; P <0.001). In the subgroup with ischemic stroke, there were no differences in stroke care delivery, except that a higher proportion of immigrants received thrombolysis than long-term residents (21.2% versus 15.5%; P <0.001). Immigrants with ischemic stroke had a higher adjusted risk of being disabled on discharge (adjusted risk ratio, 1.18; 95% CI, 1.13–1.22) compared to long-term residents.

Conclusions—

Stroke care is similar in Canadian immigrants and long-term residents. Future research is needed to confirm the observed association between immigration status and disability after stroke and to identify factors underlying the association.

Interethnic differences in neuroimaging markers and cognition in Asians, a population-based study

We examined interethnic differences in the prevalence of neuroimaging markers of cerebrovascular and neurodegenerative disease in 3 major Asian ethnicities (Chinese, Malays, and Indians), as well as their role in cognitive impairment. 3T MRI brain scans were acquired from 792 subjects (mean age: 70.0 ± 6.5years, 52.1% women) in the multi-ethnic Epidemiology of Dementia In Singapore study. Markers of cerebrovascular disease and neurodegeneration were identified. Cognitive performance was evaluated using Mini Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), and a neuropsychological assessment. Compared to Chinese, Malays had a higher burden of intracranial stenosis (OR: 2.28. 95%CI: 1.23-4.20) and cortical atrophy (β: -0.60. 95%CI: -0.78, -0.41), while Indians had a higher burden of subcortical atrophy (β: -0.23. 95%CI: -0.40, -0.06). Moreover, Malay and Indian ethnicities were likely to be cognitively impaired (OR for Malays: 3.79. 95%CI: 2.29-6.26; OR for Indians: 2.87. 95%CI: 1.74-4.74) and showed worse performance in global cognition (β for Malays: -0.51. 95%CI: -0.66, -0.37; and Indians: -0.32. 95%CI: -0.47, -0.17). A higher burden of cerebrovascular and neurodegenerative markers were found in Malays and Indians when compared to Chinese. Further research is required to fully elucidate the factors and pathways that contribute to these observed differences.

Novel Models for the Prediction of Left Atrial Appendage Thrombus in Patients with Chronic Nonvalvular Atrial Fibrillation

Predicting left atrial appendage thrombus (LAAT) in chronic nonvalvular atrial fibrillation remains challenging despite the fact that several predictive models have been proposed to date. In this study, we sought to develop new and simpler models for LAAT prediction in chronic nonvalvular atrial fibrillation. The study enrolled 144 patients with chronic nonvalvular atrial fibrillation who underwent transesophageal echocardiography for LAAT detection. We examined the association of LAAT incidence with the CHA₂DS₂-VASc score and echocardiographic parameters pertaining to the left atrium (LA), including diameter, volume index, strain, and strain rate measured on speckle tracking echocardiography. LAAT was found in 24.3% of patients (39/144). The following parameters had good diagnostic performance for LAAT: LA volume index >57 mL (area under the curve (AUC), 0.72; sensitivity, 77.1%; specificity, 64.2%), LA positive strain ≤6.7% in the four-chamber view (AUC, 0.84; sensitivity, 77.1%; specificity, 77.1%), and LA negative strain rate >−0.73 s⁻¹ in the four-chamber view (AUC, 0.83; sensitivity, 85.7%; specificity, 70.6%). The CHA₂DS₂-VASc score alone had a low predictive value for LAAT in this population (χ² = 3.53), whereas the combination of CHA₂DS₂-VASc score with LA volume index had significant association and better predictive value (χ² = 12.03), and the combination of CHA₂DS₂-VASc score with LA volume index and LA positive strain or negative strain rate in the four-chamber view had the best predictive ability for LAAT (χ²: 33.47 and 33.48, respectively). We propose two novel and simple models for noninvasive LAAT prediction in patients with chronic nonvalvular atrial fibrillation. These models combine the CHA₂DS₂-VASc score with LA volume index and LA longitudinal strain parameters measured on speckle tracking echocardiography in the four-chamber view. We hope these simple models can help with decision-making in managing the antithrombotic treatment of such patients, whose risk of stroke cannot be determined solely based on the CHA₂DS₂-VASc score.

Posterior circulation ischaemic stroke-a review part I: anatomy, aetiology and clinical presentations

Posterior circulation ischaemia is a clinicopathological condition with complex symptomatology associated with an infarction within the vertebrobasilar arterial system. Posterior circulation strokes account for about 20-25% of all ischemic strokes and remain a significant cause of patient disability and mortality. Diagnosis can be challenging because presenting symptoms are often non-focal and because there is a substantial overlap in symptoms and signs of ischaemia in the anterior circulation. Despite better imaging techniques, diagnosis and treatment of life-threatening conditions, such as basilar artery occlusions, are often delayed. Therefore, early detection of symptoms and causes of posterior circulation ischaemia is essential for choosing the most appropriate therapy. In this review, we summarise the anatomy, aetiology, typical presentations and characteristic findings of common strokes resulting from disease in the vertebrobasilar arterial system.

Stroke in the 21st Century: A Snapshot of the Burden, Epidemiology, and Quality of Life

Stroke is ranked as the second leading cause of death worldwide with an annual mortality rate of about 5.5 million. Not only does the burden of stroke lie in the high mortality but the high morbidity also results in up to 50% of survivors being chronically disabled. Thus stroke is a disease of immense public health importance with serious economic and social consequences. The public health burden of stroke is set to rise over future decades because of demographic transitions of populations, particularly in developing countries. This paper provides an overview of stroke in the 21^st century from a public health perspective.

Endovascular Therapy and Ethnic Disparities in Stroke Outcomes

BACKGROUND AND PURPOSE

Ethnic disparities in stroke are well described, with a higher incidence of disability and increased mortality in Blacks versus Whites. We sought to compare the clinical outcomes between those ethnic groups after stroke endovascular therapy (ET).

METHODS

We performed a retrospective review of the prospectively acquired Grady Endovascular Stroke Outcomes Registry between September 1, 2010 and September 30, 2015. Patients were dichotomized into two groups - Caucasians and African-Americans - and matched for age, pretreatment glucose level, and baseline National Institutes of Health Stroke Scale (NIHSS) score. Baseline characteristics as well as procedural and outcome parameters were compared.

RESULTS

Out of the 830 patients treated with ET, 308 pairs of patients (n = 616) underwent primary analysis. African-Americans were younger (p < 0.01), had a higher prevalence of hypertension (p < 0.01) and diabetes (p = 0.04), and had higher Alberta Stroke Program Early CT Score values (p = 0.03) and shorter times to treatment (p = 0.01). Blacks more frequently had Medicaid coverage and less private insurance (29.6 vs. 11.4% and 41.5 vs. 60.3%, respectively, p < 0.01). The remaining baseline characteristics, including baseline NIHSS score and CT perfusion-derived ischemic core volumes, were well balanced. There were no differences in the overall distribution of 90-day modified Rankin scale scores (p = 0.28), rates of successful reperfusion (84.7 vs. 85.7%, p = 0.91), good outcomes (49.1 vs. 44%, p = 0.24), or parenchymal hematomas (6.5 vs. 6.8%, p = 1.00). Blacks had lower 90-day mortality rates (18 vs. 24.6%, p = 0.04) in univariate analysis, which persisted as a nonsignificant trend after adjustment for potential confounders (OR 0.52, 95% CI 0.26-1.03, p = 0.06).

CONCLUSIONS

Despite unique baseline characteristics, African-Americans treated with ET for large vessel occlusion strokes have similar outcomes as Caucasians. Greater availability of ET may diminish the ethnic/racial disparities in stroke outcomes.

Low diet quality and the risk of stroke mortality: the multiethnic cohort study

BACKGROUND/OBJECTIVES

Several diets, e.g., those low in fruits/vegetables, high in sodium, and red/processed meat, have been related to a higher stroke risk. We investigated stroke mortality associated with a priori diet-quality indices in the Multiethnic Cohort study.

SUBJECTS/METHODS

Based on 172,043 observations including 3548 stroke deaths, we investigated the Healthy Eating Index-2010 (HEI-2010), the Alternative HEI-2010, the alternate Mediterranean diet score, and the Dietary Approaches to Stop Hypertension index in relation to stroke mortality. Using Cox regression, we estimated adjusted population attributable risks (PAR) and hazard ratios (HR) for tertiles of the indices while adjusting for relevant confounders.

RESULTS

The associations between all diet-quality indices and stroke mortality were consistent in direction; a low-quality diet was associated with a greater risk of stroke death, but the HEI-2010 was the strongest predictor. The PAR for stroke death based on HEI-2010 was 7.9% (95%-CI: 3.7-12.2%), indicating the preventable percentage of deaths if the total population had the same diet quality as those in the highest tertile for this diet-quality index. The lowest as compared to the highest tertile of the HEI-2010 was associated with a 1.23-fold (95%-CI: 1.13-1.34) risk. The PARs for low and medium adherence to the indices were similar by sex and follow-up time, but varied by ethnicity, with the highest PAR in Whites (15.4%) and no association in Latinos.

CONCLUSIONS

Findings for four diet-quality indices, in particular the HEI-2010, indicated that diet quality acts as an independent risk factor for stroke mortality. Promotion of a high diet quality could have a substantial impact on the prevention of stroke deaths.

Racial Difference in Cerebral Microbleed Burden Among a Patient Population in the Mid-South United States

BACKGROUND

Although intracerebral hemorrhage (ICH) is more common among African-Americans, data on the burden of cerebral microbleeds (CMBs) among different races is limited. The purpose of this study is to compare the number, associated factors, and topography of CMBs between African-American and Caucasian populations in the Mid-South United States.

METHODS

Using natural language processing, we extracted all brain MRIs performed during a 2-year period (2012-2013) when the report indicated the presence of CMB. All the extracted MRI studies were evaluated for number and location of CMBs, prior stroke, and deep white matter lesion. Negative binomial regression was used to model for the overdispersed count data.

RESULTS

A total 167 patients (mean age was 63 ± 15 years, 49% men, 77% African-American, median CMB count: 8) with 1 or more CMBs on their brain MRI were included in this study. There was no significant difference between the 2 groups in terms of CMB locations (P = .086), but there was a significant difference between African-American and Caucasian patients in terms of number of CMBs (16.5 ± 18 versus 6.5 ± 5.5, P < .001). The prevalence of multiple CMBs (CMBs ≥ 5) was similar among African-Americans and Caucasians (72% versus 55%, P = .062). After adjusting for potential confounders, the African-American race was not independently associated with a higher CMB burden (P = .073).

CONCLUSION

African-American race was not independently associated with a higher rate of CMB burden when compared to Caucasians after adjusting for potential confounders. We also did not observe a significant racial difference regarding the location and prevalence of multiple CMBs (CMBs ≥ 5).

Risk of incident atrial fibrillation in patients presenting with retinal artery or vein occlusion: a nationwide cohort study

BACKGROUND

The inter-relationships of atrial fibrillation (AF) to retinal vascular occlusions (whether retinal artery occlusion (RAO) or retinal venous occlusion (RVO)) remain unclear. It is unknown if a presentation of retinal artery or venous occlusions may indicate a new onset cardiac arrhythmia. To shed light on this association, we investigated the risk of new onset AF in patients with known RAO and RVO.

METHODS

Patients with retinal occlusions from 1997 to 2011 were identified through Danish nationwide registries and matched 1:5 according to sex and age. Cumulative incidence and unadjusted rates of AF according to retinal vascular occlusions (i.e. RAO or RVO) were determined. Hazard ratios (HR) of AF according to retinal vascular occlusion were adjusted for hypertension, diabetes, vascular disease and prior stroke/systemic thromboembolism/transient ischemic attack.

RESULTS

One thousand three hundred sixty-eight cases with retinal vascular occlusions were identified (median age 71.4 (inter quartile range (IQR); 61.2-79.8), 47.3% male). RAO constituted 706 cases (51.6%) and RVO 529 (38.7%). The rate of incident AF amongst all cases with retinal vascular occlusion was 1.74 per 100 person-years (95% confidence interval (CI), 1.47-2.06) compared to 1.22 (95% CI, 1.12-1.33) in the matched control group. The rate of AF in RAO was 2.01 (95% CI, 1.6-2.52) and 1.52 (1.15-2.01) in RVO. HRs of incident AF adjusted for cardiovascular comorbidities were 1.26 (95% CI; 1.04-1.53, p = 0.019) for any retinal vascular occlusion, 1.45 (95% CI; 1.10-1.89, p = 0.015) for RAO, and 1.02 (95% CI; 0.74-1.39, p = 0.920) for RVO.

CONCLUSIONS

A new diagnosis of retinal vascular occlusion in patients without prior AF was associated with increased risk of incident AF, particularly amongst patients with RAO. Awareness of AF in patients with retinal vascular occlusions is advised.

Racial and Ethnic Disparities in Hospital Mortality among Ischemic Stroke Patients in Hawaii

BACKGROUND

We evaluated disparities in in-hospital mortality rates among whites, Native Hawaiians and other Pacific Islanders (NHOPI), Filipinos, and other Asian groups in Hawaii who were hospitalized for acute ischemic stroke.

MATERIALS AND METHODS

Using a statewide hospital claims database, we performed a retrospective study including sequential acute ischemic stroke patients between 2010 and 2015. We compared in-hospital mortality rates among whites, NHOPI, Filipinos, other Asian groups excluding Filipinos, and other races (Blacks, Hispanics, Native Americans, mixed race).

RESULTS

A total of 13,030 patient discharges were included in this study. The mean (±SD) age in years at the time of stroke was 63.5 ± 14.3 for NHOPI, 69.6 ± 14.4 for Filipinos, 67.8 ± 14.2 for other race, 71.4 ± 13.8 for whites, and 76.1 ± 13.5 for other Asians (P < .001). NHOPI patients had higher rates of diabetes (48.8%), obesity (18.4%), and tobacco use (31.3%) compared with patients in other racial-ethnic categories. Filipino patients had the highest rate of hemorrhagic transformation (9.7%). Age-adjusted stroke mortality rates were highest among Filipinos (15.9%; 95% confidence interval [CI] = 14.3%-17.6%), followed by other Asian groups (15.1%; 95% CI = 14.0%-16.2%), NHOPI (14.8%; 95% CI = 12.8%-16.8%), other race (14.4%; 95% CI = 11.3%-17.4%), and lowest among whites (12.8%; 11.5%-14.2%). After adjusting for other confounding variables, Filipinos had higher mortality (odds ratio = 1.22, 95% CI = 1.03-1.45), whereas other Asian groups, NHOPI, and other race patients had mortality rates that were similar to whites.

CONCLUSION

In Hawaii, Filipino ethnicity is an independent risk factor for higher in-hospital stroke mortality compared with whites.

Stroke-associated pattern of gene expression previously identified by machine-learning is diagnostically robust in an independent patient population

Our group recently employed genome-wide transcriptional profiling in tandem with machine-learning based analysis to identify a ten-gene pattern of differential expression in peripheral blood which may have utility for detection of stroke. The objective of this study was to assess the diagnostic capacity and temporal stability of this stroke-associated transcriptional signature in an independent patient population. Publicly available whole blood microarray data generated from 23 ischemic stroke patients at 3, 5, and 24 h post-symptom onset, as well from 23 cardiovascular disease controls, were obtained via the National Center for Biotechnology Information Gene Expression Omnibus. Expression levels of the ten candidate genes (ANTXR2, STK3, PDK4, CD163, MAL, GRAP, ID3, CTSZ, KIF1B, and PLXDC2) were extracted, compared between groups, and evaluated for their discriminatory ability at each time point. We observed a largely identical pattern of differential expression between stroke patients and controls across the ten candidate genes as reported in our prior work. Furthermore, the coordinate expression levels of the ten candidate genes were able to discriminate between stroke patients and controls with levels of sensitivity and specificity upwards of 90% across all three time points. These findings confirm the diagnostic robustness of the previously identified pattern of differential expression in an independent patient population, and further suggest that it is temporally stable over the first 24 h of stroke pathology.

Epidemiology of Intracranial and Extracranial Large Artery Stenosis in a Population-Based Study of Stroke in the Middle East

BACKGROUND

Intracranial large-artery disease (LAD) is a predominant vascular lesion found in patients with stroke of Asian, African, and Hispanic origin, whereas extracranial LAD is more prevalent among Caucasians. These patterns are not well-established in the Middle East. We aimed to characterize the incidence, risk factors, and long-term outcome of LAD strokes in a Middle-Eastern population.

METHODS

The Mashhad Stroke Incidence Study is a community-based study that prospectively ascertained all cases of stroke among the 450,229 inhabitants of Mashhad, Iran between 2006 and 2007. Ischemic strokes were classified according to the TOAST criteria. Duplex-ultrasonography (98.6%), MR-angiography (8.3%), CT-angiography (11%), and digital-subtraction angiography (9.7%) were performed to identify involvements. Vessels were considered stenotic when the lumen was occluded by >50%.

RESULTS

We identified 72 cases (15.99 per 100,000) of incident LAD strokes (mean age 67.6 ± 11.7). Overall, 77% had extracranial LAD (58% male, mean age 69.8 ± 10.3; 50 [89%] carotid vs. 6 [11%] vertebral artery), and the remaining 23% (56% male, mean age 60.2 ± 13.4; 69% anterior-circulation stenosis) had intracranial LAD strokes. We were unable to detect differences in case-fatality between extracranial (1-year: 28.6%; 5-year: 59.8%) and intracranial diseases (1-year: 18.8%; 5-year: 36.8%; log-rank; p = 0.1).

CONCLUSION

Extracranial carotid stenosis represents the majority of LAD strokes in this population. Thus, public health strategies may best be developed in such a way that they are targeted toward the risk factors that contribute to extracranial stenosis.

Vascular Risk Factor Profiles Differ Between Magnetic Resonance Imaging-Defined Subtypes of Younger-Onset Lacunar Stroke

BACKGROUND AND PURPOSE

Differing associations of vascular risk factors with lacunar infarct have been reported, which is likely because of diagnostic differences and possible heterogeneity in the pathogenesis underlying lacunar infarction. In a large magnetic resonance imaging-verified cohort of lacunar infarct patients, we investigated the risk factor profile of lacunar infarction and magnetic resonance imaging characteristics.

METHODS

One thousand twenty-three patients with lacunar infarction (mean age, 56.7; SD, 8.5) were recruited from 72 stroke centers throughout the United Kingdom as part of the UK Young Lacunar Stroke DNA Study. Risk factor profiles were compared with 1961 stroke-free population controls with similar age. Furthermore, we tested risk factor profiles of lacunar stroke patients for association with the presence of multiple lacunar infarcts, white matter hyperintensities (WMH), and location of the acute lacunar infarct.

RESULTS

Hypertension (odds ratio [OR], 2.21; 95% confidence interval [CI], 1.85-2.64), diabetes mellitus (OR, 2.10; 95% CI, 1.61-2.73), hyperlipidemia (OR, 1.74; 95% CI, 1.46-2.07), and smoking (OR, 1.65; 95% CI, 1.39-1.96) were independently associated in lacunar infarct patients compared with healthy controls. Patients with multiple lacunar infarcts were more likely to be men (OR, 2.53; 95% CI, 1.81-3.53) and have hypertension (OR, 1.54; 95% CI, 1.12-2.04) compared with patients with a single lacunar infarct, independent of other vascular risk factors. The presence of moderate-to-severe WMH versus no or mild WMH was independently associated with increased age (OR, 1.54; 95% CI, 1.12-2.04), hypertension (OR, 2.06; 95% CI, 1.44-2.95), and impaired renal function (OR, 0.90; 95% CI, 0.82-0.98).

CONCLUSIONS

In this magnetic resonance imaging-verified lacunar stroke population, we identified a distinct risk factor profile in the group as a whole. However, there were differing risk factor profiles according to the presence of multiple lacunar infarcts and confluent WMH. The association of hypertension, smoking, and renal impairment with the presence of multiple lacunar infarcts and confluent WMH might reflect a diffuse small vessel arteriopathy.

Genetic variation at 16q24.2 is associated with small vessel stroke

Objective

Genome‐wide association studies (GWAS) have been successful at identifying associations with stroke and stroke subtypes, but have not yet identified any associations solely with small vessel stroke (SVS). SVS comprises one quarter of all ischemic stroke and is a major manifestation of cerebral small vessel disease, the primary cause of vascular cognitive impairment. Studies across neurological traits have shown that younger‐onset cases have an increased genetic burden. We leveraged this increased genetic burden by performing an age‐at‐onset informed GWAS meta‐analysis, including a large younger‐onset SVS population, to identify novel associations with stroke.

Methods

We used a three‐stage age‐at‐onset informed GWAS to identify novel genetic variants associated with stroke. On identifying a novel locus associated with SVS, we assessed its influence on other small vessel disease phenotypes, as well as on messenger RNA (mRNA) expression of nearby genes, and on DNA methylation of nearby CpG sites in whole blood and in the fetal brain.

Results

We identified an association with SVS in 4,203 cases and 50,728 controls on chromosome 16q24.2 (odds ratio [OR; 95% confidence interval {CI}] = 1.16 [1.10–1.22]; p = 3.2 × 10⁻⁹). The lead single‐nucleotide polymorphism (rs12445022) was also associated with cerebral white matter hyperintensities (OR [95% CI] = 1.10 [1.05–1.16]; p = 5.3 × 10⁻⁵; N = 3,670), but not intracerebral hemorrhage (OR [95% CI] = 0.97 [0.84–1.12]; p = 0.71; 1,545 cases, 1,481 controls). rs12445022 is associated with mRNA expression of ZCCHC14 in arterial tissues (p = 9.4 × 10⁻⁷) and DNA methylation at probe cg16596957 in whole blood (p = 5.3 × 10⁻⁶).

Interpretation

16q24.2 is associated with SVS. Associations of the locus with expression of ZCCHC14 and DNA methylation suggest the locus acts through changes to regulatory elements. Ann Neurol 2017;81:383–394

Tale of 2 Health-care Systems: Disparities in Demographic and Clinical Characteristics between 2 Ischemic Stroke Populations in Los Angeles County

BACKGROUND

Individuals who present to the emergency departments of safety-net systems often have poorly controlled risk factors due to lack of primary care. Little is known about potential differences in presenting characteristics, discharge medications, and discharge destinations of patients with acute ischemic stroke (AIS) who present to safety-net settings versus university medical centers (UMCs).

METHODS

Demographic characteristics, medical history, premorbid medication use, stroke severity, discharge medications, and discharge destination were assessed among consecutive admissions for AIS over a 2-year period at a UMC (n = 385) versus 2 university-affiliated safety-net hospitals (SNHs) (n = 346) in Los Angeles County.

RESULTS

Compared with patients presenting to the UMC, individuals admitted to the SNHs were younger, more frequently male, nonwhite, current smokers, hypertensive, and diabetic; they were less likely to take antithrombotics and statins before admission, and had worse serum lipid and glycemic markers (all P < .05). Patients admitted to the UMC trended toward more cardioembolic strokes and had higher stroke severity scores (P < .0001). At discharge, patients admitted to the SNHs were more likely to receive antihypertensive medications than do patients admitted to the UMC (P < .001), but there were no differences in prescription of antiplatelet medications or statins.

CONCLUSIONS

Individuals with AIS admitted to SNHs in Los Angeles County are younger and have poorer vascular risk factor control than their counterparts at a UMC. Discharge treatment does not vary considerably between systems. Early and more vigorous efforts at primary vascular risk reduction among patients seen at SNHs may be warranted to reduce disparities.

Early-onset and delayed-onset poststroke dementia - revisiting the mechanisms

Incident stroke has long been recognized to cause dementia shortly after the event. Patients who survive stroke without early-onset poststroke dementia (PSD) are at a high risk of developing dementia months to years after the initial stroke incident, which has generated enthusiasm for exploring treatments to prevent delayed-onset PSD in survivors of stroke. However, results from clinical trials completed in the past 10-15 years have been disappointing. In light of these results, the present Review revisits the mechanisms of both early-onset and delayed-onset PSD and proposes preventive strategies and directions for future clinical trials. Early-onset PSD results from a complex interplay between stroke lesion features and brain resilience, whereas delayed-onset PSD is associated mainly with the presence of severe sporadic small vessel disease (SVD), and to a lesser extent with Alzheimer disease pathology or recurrent stroke. As well as preventing stroke and delivering acute stroke treatments to reduce initial brain damage, measures to increase brain resilience could also reduce the risk of developing dementia if an incident stroke occurs. Future efforts to prevent delayed-onset PSD should focus on the study of sporadic SVD and on evaluating whether other strategies, in addition to conventional secondary stroke prevention, are effective in dementia prevention in this high-risk group.

Ethnic Comparison of Clinical Characteristics and Ischemic Stroke Subtypes Among Young Adult Patients With Stroke in Hawaii

BACKGROUND AND PURPOSE

Native Hawaiians and other Pacific Islanders (NHOPI) with ischemic stroke have younger age of stroke onset compared with whites. However, ethnic differences in stroke subtypes in this population have been inadequately studied.

METHODS

Consecutive young adult patients (aged ≤55 years) who were hospitalized for ischemic stroke between 2006 and 2012 at a tertiary center in Honolulu were studied. Clinical characteristics and stroke subtypes based on pathophysiological TOAST classification (Trial of Org 10172) of NHOPI and Asians were compared with whites.

RESULTS

A total of 427 consecutive young adult (mean age, 46.7±7.8 years) patients (NHOPI 45%, Asians 38%, and whites 17%) were studied. NHOPI had a higher prevalence of hypertension, diabetes mellitus, prosthetic valve, higher body mass index, hemoglobin A1c, and lower high-density lipoprotein than whites (all P<0.05). Stroke subtype distribution was not different between the ethnic groups. Specifically, the prevalence of small-vessel disease was similar between NHOPI (26.6%), whites (28.4%), and Asians (24.8%). In the univariate analyses, the use of intravenous tissue-type plasminogen activator was lower among NHOPI (4.7%; P=0.01) and Asians (3.1%; P=0.002) than among whites (12.5%). In the multivariable model, NHOPI (odds ratio, 0.35; 95% confidence interval, 0.12-0.98) and Asians (odds ratio, 0.23; 95% confidence interval, 0.07-0.74) were less likely to be treated with intravenous tissue-type plasminogen activator than whites.

CONCLUSIONS

NHOPI have greater cardiovascular risk factors than whites, but there were no differences in stroke subtypes between the ethnic groups. Furthermore, NHOPI and Asians may be less likely to be treated with intravenous tissue-type plasminogen activator than whites.

Magnetic resonance imaging characteristics of ischemic stroke in an Afro-Caribbean population: A 1-year prospective MRI study on 534 consecutive patients

PURPOSES

Few population-based MRI studies on stroke, particularly in African-descent populations, are available. Based on a 1-year Afro-Caribbean population-based study MRI, ischemic stroke characteristics were extensively analyzed.

METHODS

All strokes occurring in Martinique (390,371 inhabitants) were prospectively included. Ascertainment was based, whenever possible, on MRI. All patients were categorized as single- (subclassified as cortical, cortical-subcortical, subcortical, lacunar) or multiple-lesion pattern, and vascular (single, multiple or junctional) territory. Brain parenchyma was evaluated, based on visualization of macrobleeds, microbleeds, white-matter hyperintensities or stroke sequelae. Etiology was classified according to TOAST criteria.

RESULTS

Among 596 ischemic stroke patients included, 534 (295 men, 239 women; mean age, 71 [range 23-110] years) underwent MRI (median delay 1 day). Four hundred and eighty-eight had single-type lesion (14.8% cortical, 42.4% cortical-subcortical, 14.5% subcortical, 16.6% lacunar), involving anterior cerebral (4%), middle cerebral (63.7%), posterior cerebral artery (10.4%) or basilar trunk (11.7%) territories, with 10.3% simultaneously involving multiple territories and 4.9% junctional infarction. Etiologies were LAA (11.2%), SVD (10.7%), CE (29.6%), rare (4.5%) or undetermined (44.1%).

CONCLUSION

Our prospective, consecutive, ischemic stroke series gives a comprehensive description of ischemic stroke imaging patterns and etiologic distributions in an Afro-Caribbean population with high socio-economic status. Our patients' stroke characteristics are close to those of European-descent populations.

Inter-Rater Reliability of the CASCADE Criteria: Challenges in Classifying Arteriopathies

BACKGROUND AND PURPOSE

There are limited data about the reliability of subtype classification in childhood arterial ischemic stroke, an issue that prompted the IPSS (International Pediatric Stroke Study) to develop the CASCADE criteria (Childhood AIS Standardized Classification and Diagnostic Evaluation). Our purpose was to determine the CASCADE criteria's reliability in a population of children with stroke.

METHODS

Eight raters from the IPSS reviewed neuroimaging and clinical records of 64 cases (16 cases each) randomly selected from a prospectively collected cohort of 113 children with arterial ischemic stroke and classified them using the CASCADE criteria. Clinical data abstracted included history of present illness, risk factors, and acute imaging. Agreement among raters was measured by unweighted κ statistic.

RESULTS

The CASCADE criteria demonstrated a moderate inter-rater reliability, with an overall κ statistic of 0.53 (95% confidence interval [CI]=0.39-0.67). Cardioembolic and bilateral cerebral arteriopathy subtypes had much higher agreement (κ=0.84; 95% CI=0.70-0.99; and κ=0.90; 95% CI=0.71-1.00, respectively) than cases of aortic/cervical arteriopathy (κ=0.36; 95% CI=0.01-0.71), unilateral focal cerebral arteriopathy of childhood (FCA; κ=0.49; 95% CI=0.23-0.76), and small vessel arteriopathy of childhood (κ=-0.012; 95% CI=-0.04 to 0.01).

CONCLUSIONS

The CASCADE criteria have moderate reliability when used by trained and experienced raters, which suggests that it can be used for classification in multicenter pediatric stroke studies. However, the moderate reliability of the arteriopathic subtypes suggests that further refinement is needed for defining subtypes. Such revisions may reduce the variability in the literature describing risk factors, recurrence, and outcomes associated with childhood arteriopathy.

Obesity and Subtypes of Incident Cardiovascular Disease

BACKGROUND

Obesity is a risk factor for various subtypes of cardiovascular disease (CVD), including coronary heart disease (CHD), heart failure (HF), and stroke. Nevertheless, there are limited comparisons of the associations of obesity with each of these CVD subtypes, particularly regarding the extent to which they are unexplained by traditional CVD mediators.

METHODS AND RESULTS

We followed 13 730 participants in the Atherosclerosis Risk in Communities (ARIC) study who had a body mass index ≥18.5 and no CVD at baseline (visit 1, 1987-1989). We compared the association of higher body mass index with incident HF, CHD, and stroke before and after adjusting for traditional CVD mediators (including systolic blood pressure, diabetes mellitus, and lipid measures). Over a median follow-up of 23 years, there were 2235 HF events, 1653 CHD events, and 986 strokes. After adjustment for demographics, smoking, physical activity, and alcohol intake, higher body mass index had the strongest association with incident HF among CVD subtypes, with hazard ratios for severe obesity (body mass index ≥35 versus normal weight) of 3.74 (95% CI 3.24-4.31) for HF, 2.00 (95% CI 1.67-2.40) for CHD, and 1.75 (95% CI 1.40-2.20) for stroke (P<0.0001 for comparisons of HF versus CHD or stroke). Further adjustment for traditional mediators fully explained the association of higher body mass index with CHD and stroke but not with HF (hazard ratio 2.27, 95% CI 1.94-2.64).

CONCLUSIONS

The link between obesity and HF was stronger than those for other CVD subtypes and was uniquely unexplained by traditional risk factors. Weight management is likely critical for optimal HF prevention, and nontraditional pathways linking obesity to HF need to be elucidated.

The Epidemiology of Atrial Fibrillation and Stroke

The burden of stroke is increasing due to aging population and unhealthy lifestyle habits. The considerable rise in atrial fibrillation (AF) is due to greater diffusion of risk factors and screening programs. The link between AF and ischemic stroke is strong. The subtype most commonly associated with AF is cardioembolic stroke, which is particularly severe and shows the highest rates of mortality and permanent disability. A trend toward a higher prevalence of cardioembolic stroke in high-income countries is probably due to the greater diffusion of AF and the control of atherosclerotic of risk factors.