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HIV is known to increase the risk of both ischemic and hemorrhagic strokes. There are many postulated mechanisms for this elevated risk including an HIV-induced vasculopathy and/or coagulopathy, opportunistic infections, and cardioembolic etiologies, among others. Regarding vasculopathy, prior reports have described the various changes to the arterial vasculature that can occur in the setting of HIV, yet the appropriate workup and management of this condition remains poorly defined. Here we describe two cases of patients with HIV presenting with large vessel intracranial occlusions in the setting of ectatic extracranial vasculature accompanied by intraluminal thrombus formation. One patient underwent thrombectomy, while the other improved after receiving IV-tPA. Inferring on these cases and the existing literature, a standardized workup and treatment algorithm is proposed, emphasizing the key management decisions that should be considered on a case-by-case basis.

ObjectiveTo examine etiologic stroke subtypes and vascular risk factor profiles and their association with white matter hyperintensity (WMH) burden in patients hospitalized for acute ischemic stroke (AIS).MethodsFor the MRI Genetics Interface Exploration (MRI-GENIE) study, we systematically assembled brain imaging and phenotypic data for 3,301 patients with AIS. All cases underwent standardized web tool–based stroke subtyping with the Causative Classification of Ischemic Stroke (CCS). WMH volume (WMHv) was measured on T2 brain MRI scans of 2,529 patients with a fully automated deep-learning trained algorithm. Univariable and multivariable linear mixed-effects modeling was carried out to investigate the relationship of vascular risk factors with WMHv and CCS subtypes.ResultsPatients with AIS with large artery atherosclerosis, major cardioembolic stroke, small artery occlusion (SAO), other, and undetermined causes of AIS differed significantly in their vascular risk factor profile (all p < 0.001). Median WMHv in all patients with AIS was 5.86 cm3 (interquartile range 2.18–14.61 cm3) and differed significantly across CCS subtypes (p < 0.0001). In multivariable analysis, age, hypertension, prior stroke, smoking (all p < 0.001), and diabetes mellitus (p = 0.041) were independent predictors of WMHv. When adjusted for confounders, patients with SAO had significantly higher WMHv compared to those with all other stroke subtypes (p < 0.001).ConclusionIn this international multicenter, hospital-based cohort of patients with AIS, we demonstrate that vascular risk factor profiles and extent of WMH burden differ by CCS subtype, with the highest lesion burden detected in patients with SAO. These findings further support the small vessel hypothesis of WMH lesions detected on brain MRI of patients with ischemic stroke.

OBJECTIVE:To determine whether brain volume is associated with functional outcome after acute ischemic stroke (AIS). PATIENTS AND METHODS:This study was conducted between July 1, 2014, and March 16, 2019. We analyzed cross-sectional data of the multisite, international hospital-based MRI-Genetics Interface Exploration study with clinical brain magnetic resonance imaging obtained on admission for index stroke and functional outcome assessment. Poststroke outcome was determined using the modified Rankin Scale score (0-6; 0 = asymptomatic; 6 = death) recorded between 60 and 190 days after stroke. Demographic characteristics and other clinical variables including acute stroke severity (measured as National Institutes of Health Stroke Scale score), vascular risk factors, and etiologic stroke subtypes (Causative Classification of Stroke system) were recorded during index admission. RESULTS:Utilizing the data from 912 patients with AIS (mean ± SD age, 65.3±14.5 years; male, 532 [58.3%]; history of smoking, 519 [56.9%]; hypertension, 595 [65.2%]) in a generalized linear model, brain volume (per 155.1 cm3) was associated with age (β -0.3 [per 14.4 years]), male sex (β 1.0), and prior stroke (β -0.2). In the multivariable outcome model, brain volume was an independent predictor of modified Rankin Scale score (β -0.233), with reduced odds of worse long-term functional outcomes (odds ratio, 0.8; 95% CI, 0.7-0.9) in those with larger brain volumes. CONCLUSION:Larger brain volume quantified on clinical magnetic resonance imaging of patients with AIS at the time of stroke purports a protective mechanism. The role of brain volume as a prognostic, protective biomarker has the potential to forge new areas of research and advance current knowledge of the mechanisms of poststroke recovery.

Background and Purpose: Although the US Black population has a higher incidence of stroke compared with the US White population, few studies have addressed Black-White differences in the contribution of vascular risk factors to the population burden of ischemic stroke in young adults. Methods: A population-based case-control study of early-onset ischemic stroke, ages 15 to 49 years, was conducted in the Baltimore-Washington DC region between 1992 and 2007. Risk factor data was obtained by in-person interview in both cases and controls. The prevalence, odds ratio, and population-attributable risk percent (PAR%) of smoking, diabetes, and hypertension was determined among Black patients and White patients, stratified by sex. Results: The study included 1044 cases and 1099 controls. Of the cases, 47% were Black patients, 54% were men, and the mean (±SD) age was 41.0 (±6.8) years. For smoking, the population-attributable risk percent were White men 19.7%, White women 32.5%, Black men 10.1%, and Black women 23.8%. For diabetes, the population-attributable risk percent were White men 10.5%, White women 7.4%, Black men 17.2%, and Black women 13.4%. For hypertension, the population-attributable risk percent were White men 17.2%, White women 19.3%, Black men 45.8%, and Black women 26.4%. Conclusions: Modifiable vascular risk factors account for a large proportion of ischemic stroke in young adults. Cigarette smoking was the strongest contributor to stroke among White patients while hypertension was the strongest contributor to stroke among Black patients. These results support early primary prevention efforts focused on smoking cessation and hypertension detection and treatment.

ObjectiveTo determine the contribution of common genetic variants to risk of early onset ischemic stroke (IS).MethodsWe performed a meta-analysis of genome-wide association studies of early onset IS, ages 18-59, using individual level data or summary statistics in 16,927 cases and 576,353 non-stroke controls from 48 different studies across North America, Europe, and Asia. We further compared effect sizes at our most genome-wide significant loci between early and late onset IS and compared polygenic risk scores for venous thromboembolism between early versus later onset IS.ResultsWe observed an association between early onset IS and ABO, a known stroke locus. The effect size of the peak ABO SNP, rs8176685, was significantly larger in early compared to late onset IS (OR 1.17 (95% C.I.: 1.11-1.22) vs 1.05 (0.99-1.12); p for interaction = 0.008). Analysis of genetically determined ABO blood groups revealed that early onset IS cases were more likely to have blood group A and less likely to have blood group O compared to both non-stroke controls and to late onset IS cases. Using polygenic risk scores, we observed that greater genetic risk for venous thromboembolism, another prothrombotic condition, was more strongly associated with early, compared to late, onset IS (p=0.008).ConclusionThe ABO locus, genetically predicted blood group A, and higher genetic propensity for venous thrombosis are more strongly associated with early onset IS, compared with late onset IS, supporting a stronger role of prothrombotic factors in early onset IS.

Objective: To personalize the prognostication of post-stroke outcome using MRI-detected cerebrovascular pathology, we sought to investigate the association between the excessive white matter hyperintensity (WMH) burden unaccounted for by the traditional stroke risk profile of individual patients and their long-term functional outcomes after a stroke. Methods: We included 890 patients who survived after an acute ischemic stroke from the MRI-Genetics Interface Exploration (MRI-GENIE) study, for whom data on vascular risk factors (VRFs), including age, sex, atrial fibrillation, diabetes mellitus, hypertension, coronary artery disease, smoking, prior stroke history, as well as acute stroke severity, 3- to-6-month modified Rankin Scale score (mRS), WMH, and brain volumes, were available. We defined the unaccounted WMH (uWMH) burden via modeling of expected WMH burden based on the VRF profile of each individual patient. The association of uWMH and mRS score was analyzed by linear regression analysis. The odds ratios of patients who achieved full functional independence (mRS < 2) in between trichotomized uWMH burden groups were calculated by pair-wise comparisons. Results: The expected WMH volume was estimated with respect to known VRFs. The uWMH burden was associated with a long-term functional outcome (β = 0.104, p < 0.01). Excessive uWMH burden significantly reduced the odds of achieving full functional independence after a stroke compared to the low and average uWMH burden [OR = 0.4, 95% CI: (0.25, 0.63), p < 0.01 and OR = 0.61, 95% CI: (0.42, 0.87), p < 0.01, respectively]. Conclusion: The excessive amount of uWMH burden unaccounted for by the traditional VRF profile was associated with worse post-stroke functional outcomes. Further studies are needed to evaluate a lifetime brain injury reflected in WMH unrelated to the VRF profile of a patient as an important factor for stroke recovery and a plausible indicator of brain health. NIH-NINDS (MRI-GENIE: R01NS086905 - PI NR; K23NS064052, R01NS082285 - NR; SiGN: U01 NS069208 - JR, SK; R01NS059775, R01NS063925, R01NS082285, P50NS051343, R01NS086905, U01 NS069208 - OW); NIH NIBIB (NAC P41EB015902 PG, U01NS030678 Kissela, Kleindorfer; EB015325 OW); ISGS (R01NS423733 P.I. JM, Swedish Heart and Lung Foundation, Lund University, Region Skåne, the Freemasons Lodge of Instruction Eos Lund, Skåne University Hospital, the Foundation of Färs &Frosta (One of Sparbanken Skånes ownership Foundations), and the Swedish Stroke Association - AL, Swedish Research Council and the Swedish Heart and Lung Foundation, the Swedish State under the ALF agreement CJ, Spanish Ministry of Science and Innovation, Instituto de Salud Carlos III (Funding for Research in Health PI051737, PI10/02064, PI12/01238 and PI15/00451 JJ-C), Fondos FEDER/EDRF Red de Investigación Cardiovascular (RD12/0042/0020 JJ-C), Fundació la Marató TV3 (76/C/2011 - JJ-C) and Recercaixa13 (JJ086116 JJ-C), Wistron Corporation (PG); The European Unions Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 753896 - MS; RL is a senior clinical investigator of FWO Flanders; MB was supported by the ISITE-ULNE Fundation, the Société Française de Neuroradiologie, the Société Française de Radiologie, the Thérèse and René Planiol Fundation; ME was supported by the American Academy of Neurology and MGH Executive Council on Research; TT was supported by the Helsinki University Central Hospital, Sigrid Juselius Foundation, Sahlgrenska University Hospital, and University of Gothenburg. The funders were not involved in the study design, collection, analysis, interpretation of data, the writing of this article of the decision to submit it for publication.

ObjectiveNeuroimaging measurements of brain structural integrity are thought to be surrogates for brain health, but precise assessments require dedicated advanced image acquisitions. By means of quantitatively describing conventional images, radiomic analyses hold potential for evaluating brain health. We sought to: (1) evaluate radiomics to assess brain structural integrity by predicting white matter hyperintensities burdens (WMH) and (2) uncover associations between predictive radiomic features and clinical phenotypes.MethodsWe analyzed a multi-site cohort of 4,163 acute ischemic strokes (AIS) patients with T2-FLAIR MR images with total brain and WMH segmentations. Radiomic features were extracted from normal-appearing brain tissue (brain mask–WMH mask). Radiomics-based prediction of personalized WMH burden was done using ElasticNet linear regression. We built a radiomic signature of WMH with stable selected features predictive of WMH burden and then related this signature to clinical variables using canonical correlation analysis (CCA).ResultsRadiomic features were predictive of WMH burden (R2 = 0.855 ± 0.011). Seven pairs of canonical variates (CV) significantly correlated the radiomics signature of WMH and clinical traits with respective canonical correlations of 0.81, 0.65, 0.42, 0.24, 0.20, 0.15, and 0.15 (FDR-corrected p-valuesCV1–6 < 0.001, p-valueCV7 = 0.012). The clinical CV1 was mainly influenced by age, CV2 by sex, CV3 by history of smoking and diabetes, CV4 by hypertension, CV5 by atrial fibrillation (AF) and diabetes, CV6 by coronary artery disease (CAD), and CV7 by CAD and diabetes.ConclusionRadiomics extracted from T2-FLAIR images of AIS patients capture microstructural damage of the cerebral parenchyma and correlate with clinical phenotypes, suggesting different radiographical textural abnormalities per cardiovascular risk profile. Further research could evaluate radiomics to predict the progression of WMH and for the follow-up of stroke patients’ brain health.

Stroke in younger adults is less common than in older adults, with approximately 10-15% of all strokes occurring in adults aged 18 to 50 years of age. The pathogenesis of stroke in younger adults requires additional considerations for several less common risk factors and etiologies. As with any stroke patient, a thorough workup including evaluations of the brain, the blood vessels of the head and neck, the heart, and basic bloodwork must be performed. On the basis of these results, as well as case-specific clinical findings, family history, and other considerations, additional testing for genetic or hypercoagulable causes and specialized vascular and echocardiography can be performed. Overall, it is critical to identify the likely pathogeneses to prevent stroke recurrence. Regardless of pathogenesis, young stroke survivors with high rates of traditional risk factors must have these risk factors aggressively managed for long-term risk reduction. In this chapter, we focus on ischemic stroke in the young emphasizing a clinical evaluation framework, describing key considerations regarding etiology, treatment, and prevention that providers should contemplate in course of individualized patient care.

Acute ischemic stroke affects men and women differently. In particular, women are often reported to experience higher acute stroke severity than men. We derived a low-dimensional representation of anatomical stroke lesions and designed a Bayesian hierarchical modeling framework tailored to estimate possible sex differences in lesion patterns linked to acute stroke severity (National Institute of Health Stroke Scale). This framework was developed in 555 patients (38% female). Findings were validated in an independent cohort (n = 503, 41% female). Here, we show brain lesions in regions subserving motor and language functions help explain stroke severity in both men and women, however more widespread lesion patterns are relevant in female patients. Higher stroke severity in women, but not men, is associated with left hemisphere lesions in the vicinity of the posterior circulation. Our results suggest there are sex-specific functional cerebral asymmetries that may be important for future investigations of sex-stratified approaches to management of acute ischemic stroke., Acute ischemic stroke impacts men and women differently. Here, the authors show how different lesion patterns in men and women are linked to the extent of stroke severity.

ObjectiveStudies indicate that the functional outcome evolves in the year after ischemic stroke onset. However, the traditional outcome measure in stroke trials is the modified Rankin Scale (mRS) at 90 days from onset. To determine mRS fluctuations in the first year after stroke, we examined data from 3 major stroke trials.MethodsIn a secondary analysis, we evaluated intrapatient mRS between 90 days and 1 year from stroke onset, the mRS shift (∆mRS = 1 year-day 90), and the trials' primary outcome at day 90 and 1 yearResultsWe included 624 patients from the National Institute of Neurological Disorders and Stroke rt-PA Stroke Study, 587 from Albumin Treatment for Acute Ischaemic Stroke, and 611 from Interventional Management of Stroke III, for which the proportion of patients with a ∆mRS change between day 90 and 1 year was 36.5%, 41.7%, and 36.0%. However, the trials' primary outcomes did not differ at 1 year vs 90 days. Similar findings were seen in a second cohort where we pooled the trials and excluded patients with recurrent stroke or death during the follow-up. In those 1,314 patients, 544 (41.4%) had a ∆mRS change, of which 379 (28.9%) had improvement and 165 (12.5%) had worsening, apart from death.ConclusionWe describe the patient-level spectrum of mRS change from day 90 to 1 year after ischemic stroke in 3 high-quality randomized trials. The patient-level shifts consisted of a sufficiently counterbalanced number of mRS improvements and declines, which masked clinical evolution occurring in over one-third of patients. These results may have important implications, both for clinical trial design and outcome adjudication in stroke research and duration of rehabilitative therapy.

Background and ObjectivesTo test the hypothesis that a predisposition to acquired genetic alterations is associated with ischemic stroke outcome by investigating the association between a polygenic risk score (PRS) for mosaic loss of chromosome Y (mLOY) and outcome in a large international data set.MethodsWe used data from the genome-wide association study performed within the Genetics of Ischemic Stroke Functional Outcome network, which included 6,165 patients (3,497 men and 2,668 women) with acute ischemic stroke of mainly European ancestry. We assessed a weighted PRS for mLOY and examined possible associations with the modified Rankin Scale (mRS) score 3 months poststroke in logistic regression models. We investigated the whole study sample as well as men and women separately.ResultsIncreasing PRS for mLOY was associated with poor functional outcome (mRS score >2) with an odds ratio (OR) of 1.11 (95% confidence interval [CI] 1.03–1.19) per 1 SD increase in the PRS after adjustment for age, sex, ancestry, stroke severity (NIH Stroke Scale), smoking, and diabetes mellitus. In sex-stratified analyses, we found a statistically significant association in women (adjusted OR 1.20, 95% CI 1.08–1.33). In men, the association was in the same direction (adjusted OR 1.04, 95% CI 0.95–1.14), and we observed no significant genotype-sex interaction.DiscussionIn this exploratory study, we found associations between genetic variants predisposing to mLOY and stroke outcome. The significant association in women suggests underlying mechanisms related to genomic instability that operate in both sexes. These findings need replication and mechanistic exploration.

Introduction: Plasma concentrations of prothrombotic factors such as fibrinogen have previously been associated with ischemic stroke risk. To extend this observation, we examined the association of polygenic risk scores (PRS) for increased plasma levels of thrombosis-related factors with ischemic stroke. Our hypotheses were that these PRS would be more associated with early than late onset stroke and with non-lacunar than lacunar stroke. Methods: We identified 9053 late onset (≥ 60 years) stroke cases from the NINDS International Stroke Genetics Consortium (SiGN) with 24804 controls and 6594 early onset (< 60 years) stroke cases from the Genetics of Early Onset Ischemic Stroke Consortium with 30561 controls. We identified previously known loci associated with plasma levels of four thrombosis-related factors: fibrinogen, fibrin D-dimer, tPA and PAI-1 from prior GWAS studies and developed genome-wide PRS for plasma concentrations of these factors. We then used logistic regression to test the association of these scores with risk of stroke and stroke subtype. Results: PRS for fibrin D dimer levels were associated with increased risk for all stroke and specifically for older (p = 0.019), but not younger (p = 0.22) onset stroke. PRS for tPA levels were also marginally associated with older (p = 0.06), but not younger (p = 0.24) onset stroke. Genetic risk scores for both D dimer and tPA were associated with non-lacunar stroke (Table 1). Further analyses stratified by age revealed PRS for D dimer to be significantly associated with non-lacunar stroke (but not lacunar stroke) in both late and early onset cohorts. PRS for fibrinogen and PAI-1 were not associated with stroke. Conclusion: Genomic risk scores for thrombosis-related factors including D dimer and tPA levels were associated with risk for ischemic stroke, and specifically, non-lacunar stroke.

Background: Stroke in young adults constitutes 15-18% of all ischemic strokes. Vascular risk factors contribute to stroke risk in young adults particularly older young adults. Few studies have addressed Black White differences in risk, stratified by age. We evaluated the prevalence of risk factors in the younger young (less than 40 years) vs. the older young adults (40 and above). Methods: A population based case control study with 1034 cases and 1091 controls, ages 15-49 was used to investigate the relationship between risk factors (DM, HTN, Smoking and Obesity) and stroke. Groups were defined by the number of risk factors (RF) among cases and controls : no risk factors (ref group), one RF, two RF, three RF and four RF. Prevalence of risk factors was determined in the entire population and stratified by age, sex and race. Logistic regression was used to determine odds of stroke based on the number of risk factors compared to the reference group. Results: The percent of cases with three or more risk factors was compared in different subgroups: ages 15-39 vs. 40-49 was 8.4 vs. 21.6, women vs. men was 15.6 vs. 18.6 and White vs. Black was 12.3 vs. 22.7. Among cases 40 years and older, Blacks were 3 times more likely than Whites (5.9 vs. 2) to have four or more risk factors.Across all age, race and sex subgroups, the odds of having a stroke increased exponentially with an increase in the number of risk factors. Conclusion: Blacks are more likely to have multiple risk factors than Whites. This difference is accentuated in those 40 years and older. Targeting young adults with multiple risk factors for preventive interventions would address a root case of excess stroke risk especially among Blacks.

Introduction: While oral contraceptive (OC) use is generally safe, women at higher risk for vascular disease are advised to use alternative forms of contraception. Smoking, a prothrombotic factor, is a contraindication for OC use in women over age 35. ABO blood group, specifically the non-O blood types, has also been associated with thrombosis risk. We therefore hypothesized that the effects of smoking and OC use on stroke risk would be accentuated in women with non-O blood groups. Methods: Using data from the Genetics of Early Onset Stroke Study, we used 3 polymorphisms within the ABO locus to classify blood group type in women under age 50, including 347 cases and 383 controls. Logistic regression was used to assess the stroke risk of current OC use, defined as use within 30 days, adjusted for other risk factors, and stratified by O and non-O blood group type. Results: Of the 347 women with early-onset stroke, 45% had African ancestry, 51% had European ancestry, and 4% had other ancestry. The median age was 42 years. After adjusting for race, age, hypertension, diabetes, migraines and aura, and smoking status, the odds ratio (OR) for stroke for smoking alone and OC use alone were 3.0 (95% CI 2.1-4.2) and 3.7 (95% CI 1.7-8.4), respectively in this population. Blood group (O vs non-O) did not appreciably alter the magnitude of these associations. However, the joint risk of smoking and OC use was substantially higher in women with blood group non-O (OR = 9.5, 95% CI 3.2-34.9) vs in women with blood group O (OR=4.9, 95% CI 0.4-110.2). Conclusions: Our findings are consistent with the possibility that non-O type blood group confers an increased risk of early onset stroke among OC users who smoke. Further studies are needed to confirm or refute this possibility and to determine whether non-O blood type should be considered in assessing the risk of OC use.

Intro: In the Early Onset Stroke Consortium (EOSC) trans-ancestry analysis we found the ABO locus to be strongly associated with early onset stroke (rs529565, OR=1.10, p-value= 2.01 x 10-12). The lead SNP at this locus has a significantly larger effect size in early onset cases compared to stroke cases after age sixty and is independently associated with venous thromboembolism. This finding, in addition with previously reported candidate gene studies ( F5 , F11 , PROCR ), suggests that coagulation and hemostasis related pathways may be a major driver of early onset stroke. Motivation: To examine the genetic relationship between VTE risk burden and early onset stroke, we performed a polygenic risk score analysis to determine whether increased genetic risk for VTE was also more strongly associated with early compared to late age of onset stroke. Methods: Weighted VTE polygenetic risk scores based on recent GWAS of VTE were calculated for each individual in 7K early onset, under age 60, stroke cases from the EOSC and in 9K late onset, ages 60 and older, stroke cases from SiGN. Logistic regression was performed to test the association between the VTE-PRS score and ischemic stroke outcome controlling for sex and the first ten principal components to account for ancestry. Analyses were stratified by age of onset. Fixed effects meta-analysis was performed to combined results across the analysis strata. Results: PRS of VTE was associated with early ischemic stroke (OR=1.11, p-value=0.02) and we saw no association between VTE-PRS and late onset stroke (OR=1.04, p-value=0.5). Early cases had a greater PRS of VTE than late cases (p-value=0.01). Conclusion: While VTE has been shown to associate with stroke risk, we observed a greater genetic risk for VTE in early onset ischemic stroke compared to older onset stroke. This complements existing evidence implicating coagulation-related mechanisms as an important genetic mechanism in early onset strokes.

Introduction: The AHA notes that more than 76% of strokes are the first occurrence. There are class 1 recommendations for the management of common risk factors such as atrial fibrillation (AF), hyperlipidemia (HLD), hypertension (HTN), diabetes (DM), and vascular disease. The purpose of this study is to investigate the percentage of large vessel strokes that are potentially preventable with adequate management of vascular risk factors. Methods: A retrospective chart review was conducted on all patients undergoing endovascular therapy (EVT) from 2012-2019. Data was collected on vascular risk factors present prior to admission including HTN, DM, HLD, AF, and smoking. Preventable stroke was defined as having at least one of the following: untreated AF, untreated HLD, poorly controlled HTN (presence of left ventricular hypertrophy on transthoracic echo), history of vascular disease not on an antiplatelet agent, poorly controlled DM (A1c>10), current smoking. Groups were compared based on age, sex and 90 day functional outcomes, with favorable outcome defined as mRS ≤ 2. Results: Our sample included 396 patients who underwent EVT (mean age 65, 50% female). 42% of patients with Afib were not on anticoagulation, 31% of patients with HLD were untreated, 39% of patients with HTN were poorly controlled, 27% of patients with a history of vascular disease were not on an antiplatelet, 14% of patients with DM were poorly controlled, and 46% of all patients were smokers. In total, 78% of patients had at least 1 poorly controlled risk factor and 37% had at least 2. There was no difference in rates of preventable stroke between males and females (48% vs 52%, p=0.30) and between age groups above and below 70 (40% vs 60%, p=0.68). 64% of patients with well controlled risk factors had a favorable outcome compared to 51% with at least one poorly controlled risk factor (p=0.03). Conclusions: Our data suggests that despite guidelines on management of vascular risk factors, a large number of these are poorly controlled prior to admission for large vessel stroke, leading to a potentially preventable procedure. Not only could improved primary prevention save the wide array of resources utilized in EVT, but it could also influence long term outcomes in this cohort of patients.

IntroductionNeuroimaging measurements of brain structural integrity are thought to be surrogates for brain health, but precise assessments require dedicated advanced image acquisitions. By means of describing the texture of conventional images beyond what meets the naked eye, radiomic analyses hold potential for evaluating brain health. We sought to: 1) evaluate this novel approach to assess brain structural integrity by predicting white matter hyperintensities burdens (WMH) and 2) uncover associations between predictive radiomic features and patients’ clinical phenotypes.MethodsOur analyses were based on a multi-site cohort of 4,163 acute ischemic strokes (AIS) patients with T2-FLAIR MR images and corresponding deep-learning-generated total brain and WMH segmentation. Radiomic features were extracted from normal-appearing brain tissue (brain mask–WMH mask). Radiomics-based prediction of personalized WMH burden was done using ElasticNet linear regression. We built a radiomic signature of WMH with the most stable selected features predictive of WMH burden and then related this signature to clinical variables (age, sex, hypertension (HTN), atrial fibrillation (AF), diabetes mellitus (DM), coronary artery disease (CAD), and history of smoking) using canonical correlation analysis.ResultsRadiomic features were highly predictive of WMH burden (R2=0.855±0.011). Seven pairs of canonical variates (CV) significantly correlated the radiomics signature of WMH and clinical traits with respective canonical correlations of 0.81, 0.65, 0.42, 0.24, 0.20, 0.15, and 0.15 (FDR-corrected p-valuesCV1-6CV7=.012). The clinical CV1 was mainly influenced by age, CV2 by sex, CV3 by history of smoking and DM, CV4 by HTN, CV5 by AF and DM, CV6 by CAD, and CV7 by CAD and DM.ConclusionRadiomics extracted from T2-FLAIR images of AIS patients capture microstructural damage of the cerebral parenchyma and correlate with clinical phenotypes. Further research could evaluate radiomics to predict the progression of WMH.Research in contextEvidence before this studyWe did a systematic review on PubMed until December 1, 2020, for original articles and reviews in which radiomics were used to characterize stroke or cerebrovascular diseases. Radiomic analyses cover a broad ensemble of high-throughput quantification methods applicable to digitalized medical images that extract high-dimensional data by describing a given region of interest by its size, shape, histogram, and relationship between voxels. We used the search terms “radiomics” or “texture analysis”, and “stroke”, “cerebrovascular disease”, “small vessel disease”, or “white matter hyperintensities”. Our research identified 24 studies, 18 studying radiomics of stroke lesions and 6 studying cerebrovascular diseases. All the latter six studies were based on MRI (T1-FLAIR, dynamic contrast-enhanced imaging, T1 & T2-FLAIR, T2-FLAIR post-contrast, T2-FLAIR, and T2-TSE images). Four studies were describing small vessel disease, and two were predicting longitudinal progression of WMH. The average sample size was small with 96 patients included (maximum: 204). One study on 141 patients identified 7 T1-FLAIR radiomic features correlated with cardiovascular risk factors (age and hyperlipidemia) using univariate correlations. All studies were monocentric and performed on a single MRI scanner.Added value of this studyTo date and to the best of our knowledge, this is the largest radiomics study performed on cerebrovascular disease or any topic, and one of the very few to include a great diversity of participating sites with diverse clinical MRI scanners. This study is the first one to establish a radiomic signature of WMH and to interpret its relationship with common cardiovascular risk factors. Our findings add to the body of evidence that damage caused by small vessel disease extend beyond the visible white matter hyperintensities, but the added value resides in the detection of that subvisible damage on routinely acquired T2-FLAIR imaging. It also suggests that cardiovascular phenotypes might manifest in distinct textural patterns detectable on conventional clinical-grade T2-FLAIR images.Implications of all the available evidenceAssessing brain structural integrity has implications for treatment selection, follow-up, prognosis, and recovery prediction in stroke patients but also other neurological disease populations. Measuring cerebral parenchymal structural integrity usually requires advanced imaging such as diffusion tensor imaging or functional MRI. Translation of those neuroimaging biomarkers remains uncommon in clinical practice mainly because of their time-consuming and costly acquisition. Our study provides a potential novel solution to assess brains’ structural integrity applicable to standard, routinely acquired T2-FLAIR imaging.Future research could, for instance, benchmark this radiomics approach against diffusion or functional MRI metrics in the prediction of cognitive or functional outcomes after stroke.

Acute ischemic stroke affects men and women differently in many ways. In particular, women are oftentimes reported to experience a higher acute stroke severity than men. Here, we derived a low-dimensional representation of anatomical stroke lesions and designed a sex-aware Bayesian hierarchical modelling framework for a large-scale, well phenotyped stroke cohort. This framework was tailored to carefully estimate possible sex differences in lesion patterns explaining acute stroke severity (NIHSS) in 1,058 patients (39% female). Anatomical regions known to subserve motor and language functions emerged as relevant regions for both men and women. Female patients, however, presented a more widespread pattern of stroke severity-relevant lesions than male patients. Furthermore, particularly lesions in the posterior circulation of the left hemisphere underlay a higher stroke severity exclusively in women. These sex-sensitive lesion pattern effects could be discovered and subsequently robustly replicated in two large independent, multisite lesion datasets. The constellation of findings has several important conceptual and clinical implications: 1) suggesting sex-specific functional cerebral asymmetries, and 2) motivating a sex-stratified approach to management of acute ischemic stroke. To go beyond sex-averaged stroke research, future studies should explicitly test whether acute therapies administered on the basis of sex-specific cutoff volumes of salvageable tissue will lead to improved outcomes in women after acute ischemic stroke.

Background and Purpose: The genetic contribution to ischemic stroke may include rare- or low-frequency variants of high-penetrance and large-effect sizes. Analyses focusing on early-onset disease, an extreme-phenotype, and on the exome, the protein-coding portion of genes, may increase the likelihood of identifying such rare functional variants. To evaluate this hypothesis, we implemented a 2-stage discovery and replication design, and then addressed whether the identified variants also associated with older-onset disease. Methods: Discovery was performed in UMD-GEOS Study (University of Maryland-Genetics of Early-Onset Stroke), a biracial population-based study of first-ever ischemic stroke cases 15 to 49 years of age (n=723) and nonstroke controls (n=726). All participants had prior GWAS (Genome Wide Association Study) and underwent Illumina exome-chip genotyping. Logistic-regression was performed to test single-variant associations with all-ischemic stroke and TOAST (Trial of ORG 10172 in Acute Stroke Treatment) subtypes in Whites and Blacks. Population level results were combined using meta-analysis. Gene-based aggregation testing and meta-analysis were performed using seqMeta. Covariates included age and gender, and principal-components for population structure. Pathway analyses were performed across all nominally associated genes for each stroke outcome. Replication was attempted through lookups in a previously reported meta-analysis of early-onset stroke and a large-scale stroke genetics study consisting of primarily older-onset cases. Results: Gene burden tests identified a significant association with NAT10 in small-vessel stroke ( P =3.79×10 − 6 ). Pathway analysis of the top 517 genes ( P P −7 ), several were near, including an intronic variant in LEXM (rs7549251; P =4.08×10 − 7 ) and an exonic variant in TRAPPC11 (rs67383011; P =5.19×10 − 6 ). Conclusions: Exome-based analysis in the setting of early-onset stroke is a promising strategy for identifying novel genetic risk variants, loci, and pathways.

Background and Purpose: Approximately 8% of Blacks have sickle cell trait (SCT), and there are conflicting reports from recent cohort studies on the association of SCT with ischemic stroke (IS). Most prior studies focused on older populations, with few data available in young adults. Methods: A population-based case-control study of early-onset IS was conducted in the Baltimore-Washington region between 1992 and 2007. From this study, 342 Black IS cases, ages 15 to 49, and 333 controls without IS were used to examine the association between SCT and IS. Each participant’s SCT status was established by genotyping and imputation. For analysis, χ 2 tests and logistic regression models were performed with adjustment for potential confounding variables. Results: Participants with SCT (n=55) did not differ from those without SCT (n=620) in prevalence of hypertension, previous myocardial infarction, diabetes mellitus, and current smoking status. Stroke cases had increased prevalence in these risk factors compared with controls. We did not find an association between SCT and early-onset IS in our overall population (odds ratio=0.9 [95% CI, 0.5–1.7]) or stratified by sex in males (odds ratio=1.26 [95% CI, 0.56–2.80]) and females (odds ratio=0.67 [95% CI, 0.28–1.69]). Conclusions: Our data did not find evidence of increased risk of early-onset stroke with SCT.

Background and Purpose— We sought to explore the effect of genetic imbalance on functional outcome after ischemic stroke (IS). Methods— Copy number variation was identified in high-density single-nucleotide polymorphism microarray data of IS patients from the CADISP (Cervical Artery Dissection and Ischemic Stroke Patients) and SiGN (Stroke Genetics Network)/GISCOME (Genetics of Ischaemic Stroke Functional Outcome) networks. Genetic imbalance, defined as total number of protein-coding genes affected by copy number variations in an individual, was compared between patients with favorable (modified Rankin Scale score of 0–2) and unfavorable (modified Rankin Scale score of ≥3) outcome after 3 months. Subgroup analyses were confined to patients with imbalance affecting ohnologs—a class of dose-sensitive genes, or to those with imbalance not affecting ohnologs. The association of imbalance with outcome was analyzed by logistic regression analysis, adjusted for age, sex, stroke subtype, stroke severity, and ancestry. Results— The study sample comprised 816 CADISP patients (age 44.2±10.3 years) and 2498 SiGN/GISCOME patients (age 67.7±14.2 years). Outcome was unfavorable in 122 CADISP and 889 SiGN/GISCOME patients. Multivariate logistic regression analysis revealed that increased genetic imbalance was associated with less favorable outcome in both samples (CADISP: P =0.0007; odds ratio=0.89; 95% CI, 0.82–0.95 and SiGN/GISCOME: P =0.0036; odds ratio=0.94; 95% CI, 0.91–0.98). The association was independent of age, sex, stroke severity on admission, stroke subtype, and ancestry. On subgroup analysis, imbalance affecting ohnologs was associated with outcome (CADISP: odds ratio=0.88; 95% CI, 0.80–0.95 and SiGN/GISCOME: odds ratio=0.93; 95% CI, 0.89–0.98) whereas imbalance without ohnologs lacked such an association. Conclusions— Increased genetic imbalance was associated with poorer functional outcome after IS in both study populations. Subgroup analysis revealed that this association was driven by presence of ohnologs in the respective copy number variations, suggesting a causal role of the deleterious effects of genetic imbalance.

Global outcome measures that are widely used in stroke clinical trials, such as the modified Rankin Scale (mRS), lack sufficient detail to detect changes within specific domains (e.g., sensory, motor, visual, linguistic, or cognitive function). Yet such data are vital for understanding stroke recovery and its mechanisms. Poststroke deficits in specific domains differ in their rate and degree of recovery and in their effects on overall independence and quality of life. For example, even in a patient with complete recovery of strength, persistent deficits in the nonmotor domains such as language and cognition may make a return to independent living impossible. In such cases, global measures based solely on the patient's degree of independence would overlook a complete recovery in the motor domain. Capturing these important aspects of recovery demands a domain-specific approach. If stroke outcomes trials are to incorporate finer-grained recovery metrics—which can require substantial time, effort, and expertise to implement—efficiency must be a priority. In this article, we discuss how commonly collected clinical data from the NIH Stroke Scale can guide the judicious selection of relevant recovery domains for more detailed testing. Our overarching goal is to make the implementation of domain-specific testing more feasible for large-scale clinical trials on stroke recovery.

Backgrounds and Purpose— Although new methods for genetic analyses are rapidly evolving, there are currently knowledge gaps in how to detect Mendelian forms of stroke. Methods— We performed whole-exome sequencing in 22 probands, under 56 years at their first ischemic stroke episode, from multi-incident stroke families. With the use of a comprehensive stroke-gene panel, we searched for variants in stroke-related genes. The probands’ clinical stroke subtype was related to clinical characteristics previously associated with pathogenic variants in these genes. Relatives were genotyped in 7 families to evaluate stroke-gene variants of unknown significance. In 2 larger families with embolic stroke of unknown source, whole-exome sequencing was performed in additional members to examine the possibility of identifying new stroke genes. Results— Six of 22 probands carried pathogenic or possibly pathogenic variants in genes reported to be associated with their stroke subtype. A known pathogenic variant in NOTCH3 and a possibly pathogenic variant in ACAD9 gene were identified. A novel JAK2 :c.3188G>A (p.Arg1063His) mutation was seen in a proband with embolic stroke of undetermined source and prothrombotic status. However, penetrance in the family was incomplete. COL4A2: c.3368A>G (p.Glu1123Gly) was detected in 2 probands but did not cosegregate with the disease in their families. Whole-exome sequencing in multiple members of 2 pedigrees with embolic stroke of undetermined source revealed possibly pathogenic variants in genes not previously associated with stroke, GPR142: c.148C>G (p.Leu50Val), and PTPRN2 :c.2416A>G (p.Ile806Val); LRRC1 c.808A>G (p.Ile270Val), SLC7A10 c.1294dupG (p.Val432fs), IKBKB : c.1070C>T (p.Ala357Val), and OXGR1 c.392G>A (p.Arg131His), respectively. Conclusions— Screening with whole-exome sequencing using a comprehensive stroke-gene panel may identify rare monogenic forms of stroke, but careful evaluation of clinical characteristics and potential pathogenicity of novel variants remain important. In our study, the majority of individuals with familial aggregation of stroke lacked any identified genetic causes.

Endovascular thrombectomy following an acute ischemic stroke can lead to improved functional outcome when performed early. Current guidelines suggest treatment within 6 h after symptom onset. Recent studies including the DEFUSE-3 and DAWN trials demonstrate that some patients may benefit from thrombectomy up to 16 and 24 h after symptom onset, respectively. We present a case of delayed thrombectomy in a 43-year-old man with acute dysarthria, left-sided weakness, and visual neglect. Initial MRI/A demonstrated a small completed stroke and a thrombus in the right middle cerebral artery. Thirty-seven hours after symptom onset, his weakness acutely worsened. A repeat MRI revealed an unchanged core infarct volume and a cerebral angiogram suggested an abrupt occlusion of the right distal M1. Thrombectomy was performed with complete reperfusion and the patient’s strength recovered following the procedure. We compared our clinical reasoning with the DEFUSE-3 and DAWN study criteria, and conclude that there is a subset of patients that may safely benefit from thrombectomy in later time windows beyond the trial criteria, especially in the setting of clinical examination of imaging mismatch.

A 60-year-old woman, a nonsmoker, with medical history of hypertension and chronic back pain, presented with sudden-onset left-sided weakness and facial droop to an outside hospital with symptoms of approximately 1 hour duration. Her NIH Stroke Scale (NIHSS) score, a validated tool to quantitatively measure stroke severity,1 was 17, significant for a right gaze preference, left-sided hemiparesis, and left-sided neglect. Her initial head CT demonstrated an Alberta Stroke Programme Early CT Score (ASPECTS) of 9. ASPECTS is a 10-point quantitative CT scan topography score used to measure ischemic changes on head CT.2 The patient's head CT demonstrated subtle right basal ganglia ischemic involvement and an absence of hemorrhage. IV tissue plasminogen activator (tPA) was administered and CT angiography of the head and neck was performed, demonstrating a right middle cerebral artery (MCA) (M1) occlusion. Our institution was consulted as per protocol for ischemic strokes associated with large artery occlusion and she was transferred for potential intra-arterial (IA) thrombectomy. Upon arrival, the patient was mildly lethargic but attended to the examination; she was able to follow simple commands to open/close her eyes and make a fist. The patient was dysarthric, but with time, answered questions appropriately. She had left-sided facial weakness and right gaze preference but was able to cross midline. She demonstrated left-sided neglect to visual and tactile stimuli and was slow to move her left extremities to repeated command, with decreased left-sided extremity strength rated 4/5. NIHSS upon arrival to our institution was 9.

Background: Stroke in young adults accounts for 15-18% of all ischemic stroke (IS) cases and disproportionately affects African Americans (AfrAm). While it is well known that a higher prevalence of vascular risk factors, particularly HTN and DM, contributes to this excess risk, few studies have examined the potential contribution of the synergistic risk from multiple vascular risk factors. Methods: A population-based case-control study with 582 cases and 727 controls ages 15-49 was used to investigate the relationship of multiple risk factors and IS in young adults and compare AfrAM and White cases for the prevalence of multiple risk factors. Logistic regression analysis with adjustment for age, sex, and race was used to evaluate the association between the following mutually exclusive risk factor groups and IS: (a) Smoking alone, (b) Smoking+ HTN only, (c) Smoking + HTN +Obesity only (d) Smoking + HTN + Obesity +DM. The reference group for these analyses was those with no risk factors. Logistic regression with adjustment for age only was also used to compare AfrAM vs White cases for their prevalence in each risk factor group. Results: There were a total 218 cases with no risk factors. The odds of having an IS increased exponentially as the number of risk factors increased (OR 2.3, 95% CI 1.8 - 3.0, p Conclusion: The risk of IS increases in an exponential manner in young adults with an increasing number of traditional risk factors. Compared to their White counterparts, young AfrAm IS cases are approximately 6 times more likely to have all 4 risk factors: smoking, HTN, DM and obesity. Risk factor synergy could contribute to the excess risk of IS among young AfrAm and our study emphasizes early screening for vascular risk factors in this subgroup.

Introduction: It is well known that African Americans (Afr-Am) have a higher prevalence of hypertension (HTN) compared to Whites. Few studies have compared Afr-Am and Whites for the prevalence of left ventricular hypertrophy (LVH; a marker of long-standing hypertension) in young ischemic stroke patients with and without a history of hypertension to assess hypertension severity and undiagnosed longstanding hypertension. We hypothesized that the prevalence of LVH by echocardiography would be higher in Afr-Am than in their White counterparts. Methods: We identified 1033 patients from a population-based case control study of young patients with first-time ischemic stroke (age 18 to 49 years old, enrolled from 1992-2006) from the Baltimore-Washington area. Patients (n=191, 16%) without an echocardiogram were excluded yielding an analysis sample of 842. Prevalence of LVH by echocardiography (Echo-LVH) were determined in those with and without a history of HTN, stratified by sex and race. Age-adjusted odds ratios and 95% confidence intervals comparing Afr-Am and Whites for the prevalence of Echo-LVH were calculated by logistic regression. Results: Of the 842 young stroke patients included in this study, the median age was 43.0, 55.2% were men, and 48.7 % were Afr-Am. Echo-LVH was common in young patients with ischemic stroke, even patients without a prior history of hypertension. Afr-Am women, both with and without a history of HTN, had higher age-adjusted prevalence of LVH than White women. Afr-Am men with no history of HTN had higher age-adjusted prevalence of Echo-LVH than White men. Afr-Am men with history of HTN had the highest prevalence of LVH, but the age-adjusted comparison with White men with HTN did not achieve statistical significance. Conclusions: The evidence suggests that Afr-Am have greater end organ damage from HTN, even among those who do not have an established diagnosis of HTN. These findings emphasize the need for earlier screening and treatment of HTN in young Afr-Am adults.

Background and purpose The preponderance of evidence from recent studies in human subjects supports a negative effect of the BDNF Val66Met polymorphism on motor outcomes and motor recovery. However prior studies have generally reported the effect of the Met allele in older stroke patients, while potential effects in younger stroke patients have remained essentially unexamined. The lack of research in younger patients is significant since aging effects on CNS repair and functional recovery after stroke are known to interact with the effects of genetic polymorphisms. Here we present a study of first-ever ischemic stroke patients aged 15–49 years that examines the effect of Met carrier status on functional disability. Methods 829 patients with a first ischemic stroke (Average age = 41.4 years, SD = 6.9) were recruited from the Baltimore-Washington region. Genotyping was performed at the Johns Hopkins University Center for Inherited Disease Research (CIDR). Data cleaning and harmonization were done at the GEI-funded GENEVA Coordinating Center at the University of Washington. Our sample contained 165 Met carriers and 664 non-Met carriers. Modified Rankin scores as recorded at discharge were obtained from the hospital records by study personnel blinded to genotype, and binarized into “Good” versus “Poor” outcomes (mRS 0–2 vs. 3+), with mRS scores 3+ reflecting a degree of disability that causes loss of independence. Results Our analysis showed that the Met allele conveyed a proportionally greater risk for poor outcomes and disability-related loss of independence with mRS scores 3+ (adjusted OR 1.73, 95% CI 1.13–2.64, p = 0.01). Conclusions The BDNF Val66Met polymorphism was negatively associated with functional outcomes at discharge in our sample of 829 young stroke patients. This finding stands in contrast to what would be predicted under the tenets of the resource modulation hypothesis (i.e. that younger patients would be spared from the negative effect of the Met allele on recovery since it is posited to arise as a manifestation of age-related decline in physiologic resources).

Background and Purpose— There is a strong dose–response relationship between smoking and risk of ischemic stroke in young women, but there are few data examining this association in young men. We examined the dose–response relationship between the quantity of cigarettes smoked and the odds of developing an ischemic stroke in men under age 50 years. Methods— The Stroke Prevention in Young Men Study is a population-based case–control study of risk factors for ischemic stroke in men ages 15 to 49 years. The χ 2 test was used to test categorical comparisons. Logistic regression models were used to calculate the odds ratio for ischemic stroke occurrence comparing current and former smokers to never smokers. In the first model, we adjusted solely for age. In the second model, we adjusted for potential confounding factors, including age, race, education, hypertension, myocardial infarction, angina, diabetes mellitus, and body mass index. Results— The study population consisted of 615 cases and 530 controls. The odds ratio for the current smoking group compared with never smokers was 1.88. Furthermore, when the current smoking group was stratified by number of cigarettes smoked, there was a dose–response relationship for the odds ratio, ranging from 1.46 for those smoking Conclusions— We found a strong dose–response relationship between the number of cigarettes smoked daily and ischemic stroke among young men. Although complete smoking cessation is the goal, even smoking fewer cigarettes may reduce the risk of ischemic stroke in young men.

White matter hyperintensity (WMH) burden is a critically important cerebrovascular phenotype linked to prediction of diagnosis and prognosis of diseases, such as acute ischemic stroke (AIS). However, current approaches to its quantification on clinical MRI often rely on time intensive manual delineation of the disease on T2 fluid attenuated inverse recovery (FLAIR), which hinders high-throughput analyses such as genetic discovery. In this work, we present a fully automated pipeline for quantification of WMH in clinical large-scale studies of AIS. The pipeline incorporates automated brain extraction, intensity normalization and WMH segmentation using spatial priors. We first propose a brain extraction algorithm based on a fully convolutional deep learning architecture, specifically designed for clinical FLAIR images. We demonstrate that our method for brain extraction outperforms two commonly used and publicly available methods on clinical quality images in a set of 144 subject scans across 12 acquisition centers, based on dice coefficient (median 0.95; inter-quartile range 0.94-0.95; p < 0.01) and Pearson correlation of total brain volume (r = 0.90). Subsequently, we apply it to the large-scale clinical multi-site MRI-GENIE study (N = 2783) and identify a decrease in total brain volume of -2.4 cc/year. Additionally, we show that the resulting total brain volumes can successfully be used for quality control of image preprocessing. Finally, we obtain WMH volumes by building on an existing automatic WMH segmentation algorithm that delineates and distinguishes between different cerebrovascular pathologies. The learning method mimics expert knowledge of the spatial distribution of the WMH burden using a convolutional auto-encoder. This enables successful computation of WMH volumes of 2533 clinical AIS patients. We utilize these results to demonstrate the increase of WMH burden with age (0.950 cc/year) and show that single site estimates can be biased by the number of subjects recruited. This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 753896 (M.D. Schirmer). This study was supported by NIH-NINDS (MRI-GENIE: R01NS086905 - PI N.Rost, K23NS064052, R01NS082285 - N. Rost, SiGN: U01 NS069208 - J. Rosand, S. Kittner, R01NS059775, R01NS063925, R01NS082285,P50NS051343, R01NS086905, U01 NS069208 - O. Wu), NIH NIBIBNAC (P41EB015902–P. Golland).

Background Genetic determinants of stroke, the leading neurological cause of death and disability, are poorly understood and have seldom been explored in the general population. Our aim was to identify additional loci for stroke by doing a meta-analysis of genome-wide association studies. Methods For the discovery sample, we did a genome-wide analysis of common genetic variants associated with incident stroke risk in 18 population-based cohorts comprising 84 961 participants, of whom 4348 had stroke. Stroke diagnosis was ascertained and validated by the study investigators. Mean age at stroke ranged from 45·8 years to 76·4 years, and data collection in the studies took place between 1948 and 2013. We did validation analyses for variants yielding a significant association (at p−6) with all-stroke, ischaemic stroke, cardioembolic ischaemic stroke, or non-cardioembolic ischaemic stroke in the largest available cross-sectional studies (70 804 participants, of whom 19 816 had stroke). Summary-level results of discovery and follow-up stages were combined using inverse-variance weighted fixed-effects meta-analysis, and in-silico lookups were done in stroke subtypes. For genome-wide significant findings (at p−8), we explored associations with additional cerebrovascular phenotypes and did functional experiments using conditional (inducible) deletion of the probable causal gene in mice. We also studied the expression of orthologs of this probable causal gene and its effects on cerebral vasculature in zebrafish mutants. Findings We replicated seven of eight known loci associated with risk for ischaemic stroke, and identified a novel locus at chromosome 6p25 (rs12204590, near FOXF2) associated with risk of all-stroke (odds ratio [OR] 1·08, 95% CI 1·05–1·12, p=1·48 × 10−8; minor allele frequency 21%). The rs12204590 stroke risk allele was also associated with increased MRI-defined burden of white matter hyperintensity—a marker of cerebral small vessel disease—in stroke-free adults (n=21 079; p=0·0025). Consistently, young patients (aged 2–32 years) with segmental deletions of FOXF2 showed an extensive burden of white matter hyperintensity. Deletion of Foxf2 in adult mice resulted in cerebral infarction, reactive gliosis, and microhaemorrhage. The orthologs of FOXF2 in zebrafish (foxf2b and foxf2a) are expressed in brain pericytes and mutant foxf2b−/− cerebral vessels show decreased smooth muscle cell and pericyte coverage. Interpretation We identified common variants near FOXF2 that are associated with increased stroke susceptibility. Epidemiological and experimental data suggest that FOXF2 mediates this association, potentially via differentiation defects of cerebral vascular mural cells. Further expression studies in appropriate human tissues, and further functional experiments with long follow-up periods are needed to fully understand the underlying mechanisms. Funding NIH, NINDS, NHMRC, CIHR, European national research institutions, Fondation Leducq.

Background and Purpose— Although case reports have long identified a temporal association between cocaine use and ischemic stroke (IS), few epidemiological studies have examined the association of cocaine use with IS in young adults, by timing, route, and frequency of use. Methods— A population-based case–control study design with 1090 cases and 1154 controls was used to investigate the relationship of cocaine use and young-onset IS. Stroke cases were between the ages of 15 and 49 years. Logistic regression analysis was used to evaluate the association between cocaine use and IS with and without adjustment for potential confounders. Results— Ever use of cocaine was not associated with stroke with 28% of cases and 26% of controls reporting ever use. In contrast, acute cocaine use in the previous 24 hours was strongly associated with increased risk of stroke (age–sex–race adjusted odds ratio, 6.4; 95% confidence interval, 2.2–18.6). Among acute users, the smoking route had an adjusted odds ratio of 7.9 (95% confidence interval, 1.8–35.0), whereas the inhalation route had an adjusted odds ratio of 3.5 (95% confidence interval, 0.7–16.9). After additional adjustment for current alcohol, smoking use, and hypertension, the odds ratio for acute cocaine use by any route was 5.7 (95% confidence interval, 1.7–19.7). Of the 26 patients with cocaine use within 24 hours of their stroke, 14 reported use within 6 hours of their event. Conclusions— Our data are consistent with a causal association between acute cocaine use and risk of early-onset IS.

Background: Cerebral small vessel disease accounts for ~25-30% of strokes and is a leading cause of age- and hypertension-related cognitive decline and disability. Specific treatments for cerebral small vessel disease are lacking, and therapeutic options for secondary prevention are limited as compared to other common causes of stroke. Identifying stroke-associated protein coding variants is a promising tool to better understand disease etiology and identify novel targets. Methods: The GEOS Study was initiated as a biracial population-based study of cases with first-ever ischemic stroke 15 to 49 years of age and controls. All participants had prior GWAS and underwent Illumina exome-chip genotyping. Logistic regression analysis was conducted to identify associated variants after accounting for population substructure using Principal Component Analysis based on GWAS array data. Gene-based aggregation testing (SKAT) and meta-analysis were performed using seqMeta with ethnicity-specific GWAS PCs. Covariates for these analyses included age and gender. This was followed by Ingenuity Pathway Analyses on the top genes. Results: Gene-based testing using a filter (cumulative MAC>40, # of SNPs per gene≥2, missingness=0) was performed on 7448 genes in 123 small vessel cases and 727 non-stroke controls. Two genes reached exome wide statistical significance (p-6 ) in the meta-analyses: FNDC9 (Fibronectin type III domain containing 9, p=9.2*10 -7 ) and ASXL1 (ASXL Transcriptional Regulator 1, p=3.4*10 -7 ). Although no individual SNPs reached genome-wide significance (3x10 -7 ), a rare missense variant in ASXL1 (MAF=0.02, p=3.5*10 -6 ) was near the threshold. ASXL1 SNPs have been associated with an increased risk of CVD. Pathway analyses of the top 438 genes (p Conclusion: Exome-based analyses of small vessel young-onset ischemic stroke is a promising methodology to identify novel genetic risk variants, genes and pathways.

Background: Genome-wide association studies have identified multiple loci associated with stroke. However, the specific stroke subtypes affected, and whether loci influence both ischemic and hemorrhagic stroke, remains unknown. For loci associated with stroke, we aimed to infer the combination of stroke subtypes likely to be affected, and in doing so assess the extent to which such loci have homogeneous effects across stroke subtypes. Methods: We performed Bayesian multinomial regression in 16 664 stroke cases and 32 792 controls of European ancestry to determine the most likely combination of stroke subtypes affected for loci with published genome-wide stroke associations, using model selection. Cases were subtyped under 2 commonly used stroke classification systems, TOAST (Trial of Org 10172 Acute Stroke Treatment) and causative classification of stroke. All individuals had genotypes imputed to the Haplotype Reference Consortium 1.1 Panel. Results: Sixteen loci were considered for analysis. Seven loci influenced both hemorrhagic and ischemic stroke, 3 of which influenced ischemic and hemorrhagic subtypes under both TOAST and causative classification of stroke. Under causative classification of stroke, 4 loci influenced both small vessel stroke and intracerebral hemorrhage. An EDNRA locus demonstrated opposing effects on ischemic and hemorrhagic stroke. No loci were predicted to influence all stroke subtypes in the same direction, and only one locus (12q24) was predicted to influence all ischemic stroke subtypes. Conclusions: Heterogeneity in the influence of stroke-associated loci on stroke subtypes is pervasive, reflecting differing causal pathways. However, overlap exists between hemorrhagic and ischemic stroke, which may reflect shared pathobiology predisposing to small vessel arteriopathy. Stroke is a complex, heterogeneous disorder requiring tailored analytic strategies to decipher genetic mechanisms.

Background and Purpose— We evaluated deep learning algorithms’ segmentation of acute ischemic lesions on heterogeneous multi-center clinical diffusion-weighted magnetic resonance imaging (MRI) data sets and explored the potential role of this tool for phenotyping acute ischemic stroke. Methods— Ischemic stroke data sets from the MRI-GENIE (MRI-Genetics Interface Exploration) repository consisting of 12 international genetic research centers were retrospectively analyzed using an automated deep learning segmentation algorithm consisting of an ensemble of 3-dimensional convolutional neural networks. Three ensembles were trained using data from the following: (1) 267 patients from an independent single-center cohort, (2) 267 patients from MRI-GENIE, and (3) mixture of (1) and (2). The algorithms’ performances were compared against manual outlines from a separate 383 patient subset from MRI-GENIE. Univariable and multivariable logistic regression with respect to demographics, stroke subtypes, and vascular risk factors were performed to identify phenotypes associated with large acute diffusion-weighted MRI volumes and greater stroke severity in 2770 MRI-GENIE patients. Stroke topography was investigated. Results— The ensemble consisting of a mixture of MRI-GENIE and single-center convolutional neural networks performed best. Subset analysis comparing automated and manual lesion volumes in 383 patients found excellent correlation (ρ=0.92; P 3 (0.9–16.6 cm 3 ). Patients with small artery occlusion stroke subtype had smaller lesion volumes ( P Conclusions— Automated accurate clinical diffusion-weighted MRI lesion segmentation using deep learning algorithms trained with multi-center and diverse data is feasible. Both lesion volume and topography can provide insight into stroke subtypes with sufficient sample size from big heterogeneous multi-center clinical imaging phenotype data sets.

Comment inThe yin and yang of magnesium and calcium: New genetic insights for stroke? [Neurology. 2019]; International audience; Objective To determine whether serum magnesium and calcium concentrations are causally associated with ischemic stroke or any of its subtypes using the mendelian randomization approach. Methods Analyses were conducted using summary statistics data for 13 single-nucleotide polymorphisms robustly associated with serum magnesium (n = 6) or serum calcium (n = 7) concentrations. The corresponding data for ischemic stroke were obtained from the MEGASTROKE consortium (34,217 cases and 404,630 noncases). Results In standard mendelian randomization analysis, the odds ratios for each 0.1 mmol/L (about 1 SD) increase in genetically predicted serum magnesium concentrations were 0.78 (95% confidence interval [CI] 0.69-0.89; p = 1.3 × 10 −4) for all ischemic stroke, 0.63 (95% CI 0.50-0.80; p = 1.6 × 10 −4) for cardioembolic stroke, and 0.60 (95% CI 0.44-0.82; p = 0.001) for large artery stroke; there was no association with small vessel stroke (odds ratio 0.90, 95% CI 0.67-1.20; p = 0.46). Only the association with cardioembolic stroke was robust in sensitivity analyses. There was no association of genetically predicted serum calcium concentrations with all ischemic stroke (per 0.5 mg/dL [about 1 SD] increase in serum calcium: odds ratio 1.03, 95% CI 0.88-1.21) or with any subtype. Conclusions This study found that genetically higher serum magnesium concentrations are associated with a reduced risk of cardioembolic stroke but found no significant association of genetically higher serum calcium concentrations with any ischemic stroke subtype.

Objective Posterior circulation ischemic stroke (PCiS) constitutes 20–30% of ischemic stroke cases. Detailed information about differences between PCiS and anterior circulation ischemic stroke (ACiS) remains scarce. Such information might guide clinical decision making and prevention strategies. We studied risk factors and ischemic stroke subtypes in PCiS vs. ACiS and lesion location on magnetic resonance imaging (MRI) in PCiS. Methods Out of 3,301 MRIs from 12 sites in the National Institute of Neurological Disorders and Stroke (NINDS) Stroke Genetics Network (SiGN), we included 2,381 cases with acute DWI lesions. The definition of ACiS or PCiS was based on lesion location. We compared the groups using Chi-squared and logistic regression. Results PCiS occurred in 718 (30%) patients and ACiS in 1663 (70%). Diabetes and male sex were more common in PCiS vs. ACiS (diabetes 27% vs. 23%, p .05; male sex 68% vs. 58%, p p p p Conclusion Ischemic stroke subtypes differ between the two phenotypes. Diabetes and male sex have a stronger association with PCiS than ACiS. Definitive MRI-based PCiS diagnosis aids etiological investigation and contributes additional insights into specific risk factors and mechanisms of injury in PCiS.

Altres ajuts: The Stroke Genetics Network (SiGN) study was funded by a cooperative agreement grant from the US National Institute of Neurological Disorders and Stroke (NINDS), NIH (U01 NS069208 and R01 NS100178). SAHLSIS was supported by the Swedish Heart and Lung Foundation (HLF-20160316), the Swedish Research Council (K2014-64X-14605-12-5), the Swedish Stroke Association, the Swedish state (under the "Avtal om Läkarutbildning och Medicinsk Forskning, ALF") (ALFGBG-720081). Australian Stroke Genetics Collaboration study was supported by the National Health and Medical Research Council, Australia. Stroke Pharmacogenomics and Genetics group was supported by Invictus plus network, Generation project, and Miguel Servet programme from Instituto de Salud Carlos III, GODs project and Epigenesis project from Marató de TV3 Foundation and Agaur from Generalitat de Catalunya Government. Arne Lindgren was supported by the Swedish Heart and Lung Foundation, Region Skåne, Skåne University Hospital, the Freemasons Lodge of Instruction EOS in Lund, Lund University, the Foundation of Färs & Frosta-one of Spar-banken Skåne's ownership Foundations, and the Swedish Stroke Association. Martin Söderholm was supported by grants from the Swedish Stroke Association, the Foundation of Färs & Frosta-one of Sparbanken Skåne's ownership Foundations, and the Swedish government (under the "Avtal om Läkarutbildning och Medicinsk Forskning, ALF"). Annie Pedersen was supported by grants from the Swedish government (under the "Avtal om Läkarutbildning och Medi-cinsk Forskning, ALF") and the Gothenburg Foundation for Neurological Research. Natalia Rost was in part supported by NIH-NINDS (R01NS086905 and R01NS082285). Daniel Strbian was supported by the Finnish Subsidiary Governmental Fund (VTR). The authors thank NINDS for funding the genotyping of patients included in the SiGN study (U01 NS069208 and R01 NS100178) and Sólveig Grétarsdóttir for genotyping a subsample of the SAHLSIS cohort. ObjectiveTo discover common genetic variants associated with poststroke outcomes using a genome-wide association (GWA) study.MethodsThe study comprised 6,165 patients with ischemic stroke from 12 studies in Europe, the United States, and Australia included in the GISCOME (Genetics of Ischaemic Stroke Functional Outcome) network. The primary outcome was modified Rankin Scale score after 60 to 190 days, evaluated as 2 dichotomous variables (0-2 vs 3-6 and 0-1 vs 2-6) and subsequently as an ordinal variable. GWA analyses were performed in each study independently and results were meta-analyzed. Analyses were adjusted for age, sex, stroke severity (baseline NIH Stroke Scale score), and ancestry. The significance level was p < 5 × 10.ResultsWe identified one genetic variant associated with functional outcome with genome-wide significance (modified Rankin Scale scores 0-2 vs 3-6, p = 5.3 × 10). This intronic variant (rs1842681) in the LOC105372028 gene is a previously reported trans-Expression quantitative trait locus for PPP1R21, which encodes a regulatory subunit of protein phosphatase 1. This ubiquitous phosphatase is implicated in brain functions such as brain plasticity. Several variants detected in this study demonstrated suggestive association with outcome (p < 10), some of which are within or near genes with experimental evidence of influence on ischemic stroke volume and/or brain recovery (e.g., NTN4, TEK, and PTCH1).ConclusionsIn this large GWA study on functional outcome after ischemic stroke, we report one significant variant and several variants with suggestive association to outcome 3 months after stroke onset with plausible mechanistic links to poststroke recovery. Future replication studies and exploration of potential functional mechanisms for identified genetic variants are warranted.

Cervical artery dissection (CeAD), a common cause of ischemic stroke in young and middle-aged adults, accounts for ∼15% of all stroke in patients

Background: The genetic architecture of ischemic stroke (IS) is poorly understood and may differ by age of onset. To identify stroke susceptibility variants, genes and pathways for IS in young adults, we genotyped participants in the Genetics of Early-Onset Stroke (GEOS) with an exome array to interrogate the protein-coding portion of genes. Methods: The GEOS Study was initiated as a biracial population-based study of cases with first-ever ischemic stroke 15 to 49 years of age (n=828) and controls (n=850). All participants had prior GWAS and underwent Illumina exome-chip genotyping. Mixed model regression in EMMAX was conducted to calculate variant-specific associations using pooled European-Caucasians (EUR) and African-Americans (AA) samples, with population structure controlled by kinship matrix relationships using GWAS data. Gene-based burden testing and meta-analysis were performed using seqMeta with ethnicity-specific GWAS PCs. In both analyses covariates included age and gender. This was followed by Ingenuity Pathway Analyses on the top genes. Results: While no individual SNPs reached chip-wide significance (3x10 -7 ), several were near, including one exonic variant in TRAPPC11 (rs67383011, p=1.7*10 -6 ). Gene-based burden testing using a filter (cumulative MAC>40, # of SNPs per gene≥2, missingness=0) was performed on 6934 genes in EURs and 9423 genes in AAs. While several interesting genes were identified, notably in methylation pathways, none reached statistical significance in the ethnicity-stratified (p=3.3*10 -4 ) or meta-analyses (p=1.1*10 -4 ). Pathway analyses on the top 448 genes (p Conclusion: Exome-based analyses in the setting of early-onset stroke is a promising methodology to identify novel genetic risk variants, loci and pathways.

Introduction: Genome-wide association (GWA) studies have contributed substantially to the understanding of complex vascular traits including ischemic stroke; however, genetic determinants of acute cerebral ischemia remain to be elucidated. Objective: To investigate the genetic architecture of cerebral infarct lesion burden in patients with acute ischemic stroke (AIS). Methods: Twelve international sites contributed 3,301 AIS subjects with acute MRI and genome-wide genotyping to the MRI-GENIE study. In a preliminary analysis of 657 subjects of European ancestry, acute cerebral infarct lesions were outlined on diffusion-weighted images (DWI) using a semi-automated volumetric method. Standard quality control measures were performed per single nucleotide polymorphism (SNP) and per subject. SNPs were imputed to the Haplotype Reference Consortium v1.1 panel. Natural log-transformed DWI volume was used for GWA analysis with allelic dosage per SNP, age, sex and principal components 1-5 of genetic ancestry as covariates. Results: GWA testing for DWI volume in 7.7 million SNPs yielded no signal crossing the Bonferroni-corrected genome-wide significance threshold of p -8 . However, several loci passed the nominal significance threshold of p -6 (Figure 1), including a locus on chromosome 2 in the SPATA3-AS1 (spermatogenesis associated 3 antisense RNA 1) gene (lead SNP: rs2368999, MAF=36%, p =8.4*10 -7 ) and an intronic locus on chromosome 10 in the ATRNL1 (Attractin like 1) gene (lead SNP: rs592284, MAF=10%, p =9.1*10 -7 ). Conclusion: In this first-to-date, preliminary GWAS of acute cerebral infarct volume in AIS patients, we identified several new, nominally significant loci including a locus in ATRNL1, a gene previously linked to carotid plaque burden. Further analyses of the MRI-GENIE cohort to replicate these findings, to include stroke subtype specific analyses, and to increase the overall statistical power of the study are ongoing.

Introduction: There is a strong dose-response relationship between smoking and risk of ischemic stroke (IS) in young women, but there are few data examining this association in young men. We examined the dose-response relationship between the quantity of cigarettes smoked and the odds of developing an IS in men under age 50. Methods: The Stroke Prevention in Young Men Study is a population-based case-control study of risk factors for IS in 1145 men ages 15-49. Controls were identified by random-digit dialing and were balanced to cases for geographic region of residence, age, and ethnicity. Logistic regression models were used to calculate the odds ratio for IS occurrence comparing smokers to never smokers. In the first model, we adjusted solely for age. In the second model, we adjusted for potential confounding factors, including age, race, education, hypertension, myocardial infarction, angina, diabetes mellitus and body mass index. Interaction terms were used to examine potential effect modification by other risk factors. Statistical tests were 2-tailed and P-values less than 0.05 were considered statistically significant. Results: The table shows that IS risk increased with amount of current smoking and that 2 packs per day current smokers had over a 5-fold increased risk of IS. There were no significant interactions with other risk factors. Conclusions: We found a strong dose-response relationship between the number of cigarettes smoked daily and IS among young men. While complete smoking cessation is the goal, even reducing the number of cigarettes smoked may reduce the risk of IS in young men.

Background: Current ischemic stroke (IS) subtyping systems are very labor-intensive and costly to implement in large samples. There is a need to develop phenotyping approaches for genetic and other studies that can be implemented using generally available items captured in electronic medical records. Objective: In this report, we seek to validate a simplified approach using results from a genetic association study. Specifically, the strength of association for known genetic signals in the NINDS Stroke Genetics Network study (SiGN) is compared between the established IS subtyping systems (TOAST and Causative Classification System (CCS) subtypes) and phenotyping based on a single item within the CCS. Methods: Non-mutually exclusive “Simple” IS subtypes were defined from single CCS items as follows: 1) Small vessel stroke- lacunar infarct on imaging (with no other imaging or other requirements); 2) large artery stroke - vascular imaging showing > 50% stenosis or Results: The Table shows that, for loci significant in SiGN GWAS study, the “Simple” IS subtypes had similar strengths of association and p-values compared to results from TOAST and the causative and phenotypic CCS subtypes. Conclusions: “Simple” IS subtypes perform as well in GWAS analyses as more complex phenotyping systems and could potentially be derived through automated or semi-automated methods applied to electronic medical record systems. Since the ‘Simple” phenotypes were based on high quality CCS data, the current findings reflect optimal performance. Additional validation studies will be required for implementation in other settings.

Risk and clinical outcome of stroke, as for nearly all complex conditions, is polygenic.1 Discovering influential genetic variants offers the promise of new and personalized treatments that will substantially reduce the devastating effects of stroke on global health. Adequate power to detect multiple genetic risk alleles requires large sample sizes. Although stroke is the second leading cause of death worldwide and a major contributor to adult disability,2 no individual center can collect sufficient samples on its own. Recognizing this challenge, in 2007, stroke researchers from around the world formed the International Stroke Genetics Consortium (ISGC, http://www.strokegenetics.org). The ISGC mission is to identify genetic factors influencing stroke risk, prognosis, and treatment response by studying patients enrolled at centers around the globe. Although there has been notable early success,3–5 much work remains not only to achieve the ultimate goal of personalized medicine in stroke, finding genetic risk alleles, but also, more importantly, to develop comprehensive stroke risk assessments with actionable clinical results.6 Judging from developments in other complex diseases, such as diabetes mellitus and coronary artery disease, sample sizes of the order of 100 000 to 200 000 will be needed to identify the full range of genetic variation involved in stroke. Achieving such sample sizes requires even larger collaboration. We propose a standard methodology for data collection in stroke genetics studies to establish a best practice approach, sharing lessons learned through the ISGC. We outline the appropriate selection of case and control subjects and delineate the phenotypic data to collect, including minimum and preferred data points. Minimum requirements are prerequisites for inclusion in basic stroke genetic studies. Preferred data elements enable centers to participate in a broader variety of collaborations, such as those exploring gene–environment interactions, imaging endophenotypes, such as white matter hyperintensities, and functional …

Optimal diagnosis and management of stroke in young adults benefit from a multidisciplinary team, including a vascular neurology specialist. In addition to the “standard” vascular risk factors including smoking, hypertension, diabetes, and hyperlipidemia, one needs to consider alternative etiologies including substance abuse, carotid/vertebral artery dissections, and rare genetic conditions among others. Once a young patient is determined to have had a stroke, the next question a clinician should ask is why did this patient have a stroke? A “heart to head” diagnostic approach is recommended. A thorough history is performed, including a detailed family history with specific annotations on each family member. A thorough physical examination is necessary including a careful evaluation of the patient’s general appearance, noting any joint laxity, and/or abnormalities of the skin, eyes, and heart. Findings across multiple organ systems in the patient and/or their family may indicate a genetic etiology. After an initial head CT rules out hemorrhagic stroke, additional testing should include a brain MRI, neck and cerebral vascular imaging (e.g., CTA for head and neck), transthoracic echocardiogram with a bubble study, telemetry monitoring, basic risk factor blood work (e.g., lipid panel, hemoglobin A1c, TSH, ESR, CRP, RPR, HIV, and toxicology screen), and, when appropriate, sickle screen and pregnancy test. There should be a low threshold to obtain blood cultures or a lumbar puncture. The acute treatment of ischemic stroke in young adult patients does not differ from treatment of older adults, using intravenous alteplase within 4.5 h, assuming no contraindications. In suspected proximal large artery occlusive disease, interventional clot extraction procedures should be employed in patients deemed eligible. Long-term secondary prevention strategies aimed to reduce recurrent stroke risk by targeting and modifying vascular risk factors should be instituted. The mainstay of preventative therapy is aspirin for most etiologies; however, for atrial fibrillation, anticoagulation is recommended. Statin therapy is another pharmacologic intervention recommended in most stroke patients. Other measures employed are blood pressure reduction, smoking cessation, optimal glucose control in diabetic patients, the initiation of a healthy diet and regular exercise, and lastly, substance abuse counseling in appropriate patients.

Tobacco smoke contains numerous agonists of the aryl hydrocarbon receptor (AhR) pathway, and activation of the AhR pathway was shown to promote atherosclerosis in mice. Intriguingly, cigarette smoking is most strongly and robustly associated with DNA modifications to an AhR pathway gene, the AhR repressor (AHRR). We hypothesized that altered AHRR methylation in monocytes, a cell type sensitive to cigarette smoking and involved in atherogenesis, may be a part of the biological link between cigarette smoking and atherosclerosis.DNA methylation profiles of AHRR in monocytes (542 CpG sites ± 150 kb of AHRR, using Illumina 450K array) were integrated with smoking habits and ultrasound-measured carotid plaque scores from 1256 participants of the Multi-Ethnic Study of Atherosclerosis (MESA). Methylation of cg05575921 significantly associated (P=6.1 × 10(-134)) with smoking status (current versus never). Novel associations between cg05575921 methylation and carotid plaque scores (P=3.1 × 10(-10)) were identified, which remained significant in current and former smokers even after adjusting for self-reported smoking habits, urinary cotinine, and well-known cardiovascular disease risk factors. This association replicated in an independent cohort using hepatic DNA (n=141). Functionally, cg05575921 was located in a predicted gene expression regulatory element (enhancer) and had methylation correlated with AHRR mRNA profiles (P=1.4 × 10(-17)) obtained from RNA sequencing conducted on a subset (n=373) of the samples.These findings suggest that AHRR methylation may be functionally related to AHRR expression in monocytes and represents a potential biomarker of subclinical atherosclerosis in smokers.

Background Factor V Leiden (FVL) has been associated with ischemic stroke in children but not in adults. Although the FVL mutation is associated with increased risk for venous thrombosis, its association with ischemic stroke in young adults remains uncertain. Therefore, we examined the association between FVL and ischemic stroke in participants of the Genetics of Early Onset Stroke (GEOS) study. Methods A population-based case control study identified 354 women and 476 men 15 to 49 years of age with first-ever ischemic stroke and 907 controls. Participant-specific data included vascular risk factors, FVL genotype and, for cases, the ischemic stroke subtype by modified Trial of ORG 10172 in Acute Stroke criteria. Logistic regression was used to calculate odds ratios for the entire population and for subgroups stratified by risk factors and ischemic stroke subtype. Results The frequency of the FVL mutation was similar between ischemic stroke patients (3.6%; 95% confidence interval [CI] 2.5%-5.1%) and nonstroke controls (3.8%; 95% CI 2.7%-5.2%). This frequency did not change significantly when cases were restricted to patients with stroke of undetermined etiology (4.1%; 95% CI 2.6%-6.4%). Conclusions Among young adults, we found no evidence for an association between FVL and either all ischemic stroke or the subgroup with stroke of undetermined etiology.