Genome-Wide Association Study Identifies First Locus Associated with Susceptibility to Cerebral Venous Thrombosis.

OBJECTIVE: Cerebral venous thrombosis (CVT) is an uncommon form of stroke affecting mostly young individuals. Although genetic factors are thought to play a role in this cerebrovascular condition, its genetic etiology is not well understood. METHODS: A genome-wide association study was performed to identify genetic variants influencing susceptibility to CVT. A 2-stage genome-wide study was undertaken in 882 Europeans diagnosed with CVT and 1,205 ethnicity-matched control subjects divided into discovery and independent replication datasets. RESULTS: In the overall case-control cohort, we identified highly significant associations with 37 single nucleotide polymorphisms (SNPs) within the 9q34.2 region. The strongest association was with rs8176645 (combined p = 9.15 × 10-24 ; odds ratio [OR] = 2.01, 95% confidence interval [CI] = 1.76-2.31). The discovery set findings were validated across an independent European cohort. Genetic risk score for this 9q34.2 region increases CVT risk by a pooled estimate OR = 2.65 (95% CI = 2.21-3.20, p = 2.00 × 10-16 ). SNPs within this region were in strong linkage disequilibrium (LD) with coding regions of the ABO gene. The ABO blood group was determined using allele combination of SNPs rs8176746 and rs8176645. Blood groups A, B, or AB, were at 2.85 times (95% CI = 2.32-3.52, p = 2.00 × 10-16 ) increased risk of CVT compared with individuals with blood group O. INTERPRETATION: We present the first chromosomal region to robustly associate with a genetic susceptibility to CVT. This region more than doubles the likelihood of CVT, a risk greater than any previously identified thrombophilia genetic risk marker. That the identified variant is in strong LD with the coding region of the ABO gene with differences in blood group prevalence provides important new insights into the pathophysiology of CVT. ANN NEUROL 2021;90:777-788.

Delayed Development of Aneurysmal Dilatations in Patients with Extracranial Carotid Artery Dissections.

OBJECTIVE: Dissection of the carotid artery (CaAD) may result in aneurysm formation. The present study was undertaken to evaluate the time of onset of post-dissection extracranial carotid artery aneurysms (ECAA) following CaAD, and to analyse independent risk factors for the development of these aneurysms. METHODS: From four European stroke centres, 360 patients with extracranial CaAD were included. The time between the estimated dissection onset and aneurysm formation was analysed, and the clinical risk factors increasing the probability of aneurysm were assessed. RESULTS: The median duration of follow up was 5.2 months (range 0 - 24 months). A total of 75 post-dissection ECAAs were identified in 70 patients (19.4%, 95% confidence interval [CI] 15.7 - 23.8). In 52 of 70 (74%) patients, the ECAA was diagnosed at the initial clinical work up of CaAD diagnosis, with the median estimated time of dissection onset to ECAA diagnosis being six days (interquartile range [IQR] 0 - 25). In the remaining 18 (26%) patients who had normal carotid arteries at the initial imaging, the aneurysm diagnosis was made a median of 6.2 months (189 days) from the original imaging (IQR 128 - 198). A Cox proportional hazards model showed that both multiple artery dissections (hazard ratio [HR] 2.58, 95% CI 1.54 - 4.33) and arterial tortuosity (HR 1.79, 95% CI 1.08 - 2.95) were associated with presence of ipsilateral ECAA. CONCLUSION: This post hoc cohort analysis showed substantially delayed development of ipsilateral ECAA in patients with CaAD, months after baseline. Multiple dissections and arterial tortuosity are associated with the presence of ECAA and can be used in future prediction models of ECAA development in patients with CaAD.

Genetic Imbalance Is Associated With Functional Outcome After Ischemic Stroke.

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.

Genetic Imbalance in Patients with Cervical Artery Dissection.

BACKGROUND: Genetic and environmental risk factors are assumed to contribute to the susceptibility to cervical artery dissection (CeAD). To explore the role of genetic imbalance in the etiology of CeAD, copy number variants (CNVs) were identified in high-density microarrays samples from the multicenter CADISP (Cervical Artery Dissection and Ischemic Stroke Patients) study and from control subjects from the CADISP study and the German PopGen biobank. Microarray data from 833 CeAD patients and 2040 control subjects (565 subjects with ischemic stroke due to causes different from CeAD and 1475 disease-free individuals) were analyzed. Rare genic CNVs were equally frequent in CeAD-patients (16.4%; n=137) and in control subjects (17.0%; n=346) but differed with respect to their genetic content. Compared to control subjects, CNVs from CeAD patients were enriched for genes associated with muscle organ development and cell differentiation, which suggests a possible association with arterial development. CNVs affecting cardiovascular system development were more common in CeAD patients than in control subjects (p=0.003; odds ratio (OR) =2.5; 95% confidence interval (95% CI) =1.4-4.5) and more common in patients with a familial history of CeAD than in those with sporadic CeAD (p=0.036; OR=11.2; 95% CI=1.2-107). CONCLUSION: The findings suggest that rare genetic imbalance affecting cardiovascular system development may contribute to the risk of CeAD. Validation of these findings in independent study populations is warranted.

Genome-Wide Association Analysis of Young-Onset Stroke Identifies a Locus on Chromosome 10q25 Near HABP2.

BACKGROUND AND PURPOSE: Although a genetic contribution to ischemic stroke is well recognized, only a handful of stroke loci have been identified by large-scale genetic association studies to date. Hypothesizing that genetic effects might be stronger for early- versus late-onset stroke, we conducted a 2-stage meta-analysis of genome-wide association studies, focusing on stroke cases with an age of onset <60 years. METHODS: The discovery stage of our genome-wide association studies included 4505 cases and 21 968 controls of European, South-Asian, and African ancestry, drawn from 6 studies. In Stage 2, we selected the lead genetic variants at loci with association P<5×10(-6) and performed in silico association analyses in an independent sample of ≤1003 cases and 7745 controls. RESULTS: One stroke susceptibility locus at 10q25 reached genome-wide significance in the combined analysis of all samples from the discovery and follow-up stages (rs11196288; odds ratio =1.41; P=9.5×10(-9)). The associated locus is in an intergenic region between TCF7L2 and HABP2. In a further analysis in an independent sample, we found that 2 single nucleotide polymorphisms in high linkage disequilibrium with rs11196288 were significantly associated with total plasma factor VII-activating protease levels, a product of HABP2. CONCLUSIONS: HABP2, which encodes an extracellular serine protease involved in coagulation, fibrinolysis, and inflammatory pathways, may be a genetic susceptibility locus for early-onset stroke.

Genetic Insights on the Relation of Vascular Risk Factors and Cervical Artery Dissection.

BACKGROUND: The association between vascular risk factors and cervical artery dissections (CeADs), a leading cause of ischemic stroke (IS) in the young, remains controversial. OBJECTIVES: This study aimed to explore the causal relation of vascular risk factors with CeAD risk and recurrence and compare it to their relation with non-CeAD IS. METHODS: This study used 2-sample Mendelian randomization analyses to explore the association of blood pressure (BP), lipid levels, type 2 diabetes, waist-to-hip ratio, smoking, and body mass index with CeAD and non-CeAD IS. To simulate effects of the most frequently used BP-lowering drugs, this study constructed genetic proxies and tested their association with CeAD and non-CeAD IS. In analyses among patients with CeAD, the investigators studied the association between weighted genetic risk scores of vascular risk factors and the risk of multiple or early recurrent dissections. RESULTS: Genetically determined higher systolic BP (OR: 1.51; 95% CI: 1.32-1.72) and diastolic BP (OR: 2.40; 95% CI: 1.92-3.00) increased the risk of CeAD (P < 0.0001). Genetically determined higher body mass index was inconsistently associated with a lower risk of CeAD. Genetic proxies for ß-blocker effects were associated with a lower risk of CeAD (OR: 0.65; 95% CI: 0.50-0.85), whereas calcium-channel blockers were associated with a lower risk of non-CeAD IS (OR: 0.75; 95% CI: 0.63-0.90). Weighted genetic risk scores for systolic BP and diastolic BP were associated with an increased risk of multiple or early recurrent CeAD. CONCLUSIONS: These results are supportive of a causal association between higher BP and increased CeAD risk and recurrence and provide genetic evidence for lower CeAD risk under ß-blockers. This may inform secondary prevention strategies and trial design for CeAD.

Recurrent ischemic events in young adults after first-ever ischemic stroke.

OBJECTIVE: Data on recurrence of vascular events and their prognostic factors in young (<50 years of age) stroke patients are not well defined. METHODS: We assessed the occurrence of arterial thrombotic events in consecutive first-ever ischemic stroke patients aged 15 to 49 years entered into the Helsinki Young Stroke Registry (January 1994-October 2004) within 5-year follow-up. Follow-up was conducted with a structured telephone interview or letter, and review of all patient records; mortality data came from Statistics Finland. Primary outcomes were (1) nonfatal or fatal recurrent ischemic stroke; (2) nonfatal or fatal myocardial infarct, other arterial thrombotic event, or revascularization procedure; and (3) any combination of these, whichever occurred first (composite endpoint). We used Kaplan-Meier analysis to estimate cumulative risks and Cox proportional hazard model-adjusted for age, gender, relevant risk factors, and stroke subtype-for identifying predictors of recurrence. RESULTS: In the 807 patients followed (mean age, 41.5 ± 7.4 years; 62.9% male), cumulative 5-year recurrence rate was 9.4% (95% confidence interval [CI], 7.3-11.5%) for nonfatal or fatal ischemic stroke, 2.4% (95% CI, 1.3-3.5%) for nonfatal or fatal myocardial infarct or other arterial endpoint, and 11.5% (95% CI, 9.2-13.7%) for the composite endpoint. Independent predictors of the composite endpoint were type 1 diabetes mellitus (hazard ratio [HR], 4.39; 95% CI, 2.28-8.45), large-artery atherosclerosis underlying the index stroke (HR, 2.82; 95% CI, 1.36-5.83), heart failure (HR, 2.96; 95% CI, 1.17-7.50), previous transient ischemic attack (HR, 2.33; 95% CI, 1.40-3.88), and increasing age (HR, 1.05; 95% CI, 1.01-1.10). INTERPRETATION: Despite their young age, these individuals were at marked risk of recurrent arterial events, predicted by mostly modifiable baseline factors.

Artery occlusion independently predicts unfavorable outcome in cervical artery dissection.

OBJECTIVE: To assess the impact of dissected artery occlusion (DAO) on functional outcome and complications in patients with cervical artery dissection (CeAD). METHODS: We analyzed combined individual patient data from 3 multicenter cohorts of consecutive patients with CeAD (the Cervical Artery Dissection and Ischemic Stroke Patients [CADISP]-Plus consortium dataset). Patients with data on DAO and functional outcome were included. We compared patients with DAO to those without DAO. Primary outcome was favorable functional outcome (i.e., modified Rankin Scale [mRS] score 0-1) measured 3-6 months from baseline. Secondary outcomes included delayed cerebral ischemia, major hemorrhage, recurrent CeAD, and death. We performed univariate and multivariable binary logistic regression analyses and calculated odds ratios (OR) with 95% confidence intervals (CI), with adjustment for potential confounders. RESULTS: Of 2,148 patients (median age 45 years [interquartile range (IQR) 38-52], 43.6% women), 728 (33.9%) had DAO. Patients with DAO more frequently presented with cerebral ischemia (84.6% vs 58.5%, p < 0.001). Patients with DAO were less likely to have favorable outcome when compared to patients without DAO (mRS 0-1: 59.6% vs 80.1%, p unadjusted < 0.001). After adjustment for age, sex, and initial stroke severity, DAO was independently associated with less favorable outcome (mRS 0-1: OR 0.65, CI 0.50-0.84, p = 0.001). Delayed cerebral ischemia occurred more frequently in patients with DAO than in patients without DAO (4.5% vs 2.9%, p = 0.059). CONCLUSION: DAO independently predicts less favorable functional outcome in patients with CeAD. Further research on vessel patency, collateral status and effects of revascularization therapies particularly in patients with DAO is warranted.

Analysis of 1008 consecutive patients aged 15 to 49 with first-ever ischemic stroke: the Helsinki young stroke registry.

BACKGROUND AND PURPOSE: To analyze trends in occurrence, risk factors, etiology, and neuroimaging features of ischemic stroke in young adults in a large cohort. METHODS: We evaluated all 1008 consecutive ischemic stroke patients aged 15 to 49 admitted to Helsinki University Central Hospital, 1994 to 2007. Etiology was classified by Trial of Org 10172 in Acute Stroke Treatment criteria. Comparisons were done between groups stratified by gender and age. RESULTS: Estimated annual occurrence was 10.8/100,000 (range 8.4 to 13.0), increasing exponentially with aging. Of our 628 male and 380 female (ratio 1.7:1) patients, females were preponderant among those <30, whereas male dominance rapidly increased around age of 44. The most frequent risk factors were dyslipidemia (60%), smoking (44%), and hypertension (39%). Males and patients >44 clearly had more risk factors. Cardioembolism (20%) and cervicocerebral artery dissection (15%) were the most frequent etiologic subgroups. Proportions of large-artery atherosclerosis (8%) and small-vessel disease (14%) began to enlarge at age 35, whereas frequency of undetermined etiology (33%) decreased along aging. Posterior circulation infarcts were more common among patients <45 years of age. Left hemisphere infarcts were more frequent in general. There were 235 (23%) patients with multiple and 126 (13%) with silent infarcts, and 55 (5%) patients had leukoaraiosis. CONCLUSIONS: The frequency of ischemic stroke increases sharply at age 40. Etiology and risk factors start resembling those seen in the elderly in early midlife but causes defined in younger patients still are frequent in those aged 45 to 49. Subclinical infarcts were surprisingly common in the young.

Thrombolysis in young adults with ischemic stroke.

BACKGROUND AND PURPOSE: No exclusive systematic data exist on the safety and outcomes of thrombolytic treatment in young patients with ischemic stroke. METHODS: We evaluated all 48 patients aged 16 to 49 years with hemispheric ischemic stroke treated with intravenous alteplase in Helsinki University Central Hospital from 1994 to 2007. For comparison of outcome, we selected, blinded to outcome data, 96 control subjects (1:2) with ischemic stroke not treated with alteplase matched by age, gender, and admission stroke severity (National Institutes of Health Stroke Scale). We selected similarly 96 older alteplase-treated gender and arrival National Institutes of Health Stroke Scale score-matched patients (aged, 50 to 79 years) for comparison of outcome and hemorrhage rate. A 3-month favorable outcome was defined as modified Rankin Scale score of 0 to 1. Symptomatic intracerebral hemorrhage was defined according to the Safe Implementation of Thrombolysis in Stroke Monitor Study. RESULTS: Young alteplase-treated patients (67% males; mean age, 38.8+/-9.1 years) more often recovered completely (27% versus 10%, P=0.010) and achieved a favorable outcome (40% versus 22%, P=0.025) compared with their age-matched control subjects not treated with alteplase. In alteplase-treated patients, unfavorable outcome was more frequent in males and in those with carotid artery dissection. We observed no difference in outcome between cases and older control subjects treated with alteplase. However, none of the cases had symptomatic intracerebral hemorrhage versus 3 (3%) in the older control group (P=0.551). Mortality rate was 2% (P=0.552) in age-matched control subjects and 7% (P=0.095) among older control subjects, whereas none of the case patients died during the 3-month follow-up. CONCLUSIONS: Young adults with acute hemispheric ischemic stroke benefited from intravenous thrombolysis with good safety.

University education and cervical artery dissection.

BACKGROUND AND PURPOSE: We investigated whether university education is more likely in cervical artery dissection (CeAD)-patients than in age- and sex-matched patients with ischemic stroke (IS) due to other causes (non-CeAD-IS-patients). METHODS: Patients from the Cervical Artery Dissection and Ischemic Stroke Patients study with documented self-reported profession before onset of IS due to CeAD (n = 715) or non-CeAD causes (n = 631) were analyzed. In the reported profession, the absence or presence of university education was assessed. Professions could be rated as academic or non-academic in 518 CeAD and 456 non-CeAD patients. Clinical outcome at 3 months was defined as excellent if modified Rankin Scale was 0-1. RESULTS: University education was more frequent in CeAD-patients (100 of 518, 19.3%) than in non-CeAD-IS-patients (61 of 456, 13.4%, p = 0.008). CeAD-patients with and without university education differed significantly with regard to smoking (39 vs. 57%, p = 0.001) and excellent outcome (80 vs. 66%, p = 0.004). In logistic regression analysis, university education was associated with excellent outcome in CeAD-patients (OR 2.44, 95% CI 1.37-5.38) independent of other outcome predictors such as age (OR 0.97, 95% CI 0.84-0.99), NIHSS (OR 0.80, 95% CI 0.76-0.84) and local signs (OR 2.77, 95% CI 1.37-5.57). CONCLUSION: We observed a higher rate of university education in patients with CeAD compared with non-CeAD patients in our study population. University education was associated with favorable outcome in CeAD-patients. The mechanism behind this association remains unclear.

Determinants and outcome of multiple and early recurrent cervical artery dissections.

OBJECTIVE: To assess putative risk factors and outcome of multiple and early recurrent cervical artery dissection (CeAD). METHODS: We combined data from 2 multicenter cohorts and compared patients with multiple CeAD at initial diagnosis, early recurrent CeAD within 3 to 6 months, and single nonrecurrent CeAD. Putative risk factors, clinical characteristics, functional outcome, and risk of recurrent ischemic events were assessed. RESULTS: Of 1,958 patients with CeAD (mean ± SD age 44.3 ± 10 years, 43.9% women), 1,588 (81.1%) had single nonrecurrent CeAD, 340 (17.4%) had multiple CeAD, and 30 (1.5%) presented with single CeAD at admission and had early recurrent CeAD. Patients with multiple or early recurrent CeAD did not significantly differ with respect to putative risk factors, clinical presentation, and outcome. In multivariable analyses, patients with multiple or early recurrent CeAD more often had recent infection (odds ratio [OR] 1.81, 95% confidence interval [CI] 1.29-2.53), vertebral artery dissection (OR 1.82, 95% CI 1.34-2.46), family history of stroke (OR 1.55, 95% CI 1.06-2.25), cervical pain (OR 1.36, 95% CI 1.01-1.84), and subarachnoid hemorrhage (OR 2.85, 95% CI 1.01-8.04) at initial presentation compared to patients with single nonrecurrent CeAD. Patients with multiple or early recurrent CeAD also had a higher incidence of cerebral ischemia (hazard ratio 2.77, 95% CI 1.49-5.14) at 3 to 6 months but no difference in functional outcome compared to patients with single nonrecurrent CeAD. CONCLUSION: Patients with multiple and early recurrent CeAD share similar risk factors, clinical characteristics, and functional outcome. Compared to patients with single nonrecurrent CeAD, they are more likely to have recurrent cerebral ischemia at 3 to 6 months, possibly reflecting an underlying transient vasculopathy.

Genetics of the thrombomodulin-endothelial cell protein C receptor system and the risk of early-onset ischemic stroke.

BACKGROUND AND PURPOSE: Polymorphisms in coagulation genes have been associated with early-onset ischemic stroke. Here we pursue an a priori hypothesis that genetic variation in the endothelial-based receptors of the thrombomodulin-protein C system (THBD and PROCR) may similarly be associated with early-onset ischemic stroke. We explored this hypothesis utilizing a multi-stage design of discovery and replication. METHODS: Discovery was performed in the Genetics-of-Early-Onset Stroke (GEOS) Study, a biracial population-based case-control study of ischemic stroke among men and women aged 15-49 including 829 cases of first ischemic stroke (42.2% African-American) and 850 age-comparable stroke-free controls (38.1% African-American). Twenty-four single-nucleotide-polymorphisms (SNPs) in THBD and 22 SNPs in PROCR were evaluated. Following LD pruning (r2≥0.8), we advanced uncorrelated SNPs forward for association analyses. Associated SNPs were evaluated for replication in an early-onset ischemic stroke population (onset-age<60 years) consisting of 3676 cases and 21118 non-stroke controls from 6 case-control studies. Lastly, we determined if the replicated SNPs also associated with older-onset ischemic stroke in the METASTROKE data-base. RESULTS: Among GEOS Caucasians, PROCR rs9574, which was in strong LD with 8 other SNPs, and one additional independent SNP rs2069951, were significantly associated with ischemic stroke (rs9574, OR = 1.33, p = 0.003; rs2069951, OR = 1.80, p = 0.006) using an additive-model adjusting for age, gender and population-structure. Adjusting for risk factors did not change the associations; however, associations were strengthened among those without risk factors. PROCR rs9574 also associated with early-onset ischemic stroke in the replication sample (OR = 1.08, p = 0.015), but not older-onset stroke. There were no PROCR associations in African-Americans, nor were there any THBD associations in either ethnicity. CONCLUSION: PROCR polymorphisms are associated with early-onset ischemic stroke in Caucasians.

Prognosis and safety of anticoagulation in intracranial artery dissections in adults.

BACKGROUND AND PURPOSE: To characterize different forms of intracranial artery dissections (IADs), and to test the assumption that IADs are frequently associated with subarachnoid hemorrhage (SAH) and poor outcome, and that anticoagulant therapy is contraindicated in these patients. METHODS: We studied 81 consecutive non-SAH IAD patients and 22 IAD patients with SAH, diagnosed between 1994 and 2004 and 1998 and 2004, respectively, and treated the former patients immediately with heparin, followed with at least 3 months of warfarin. Outcomes were recorded at 3 months. RESULTS: Approximately one-third of all cervicocephalic artery dissections were identifiably either completely located intracranially or extended into the intracranial space. At 3 months, 64 of the 81 non-SAH patients (79%) had a favorable outcome (modified Rankin Scale, 0 to 2); 1 patient died of brain infarction in the acute stage. Only 1 aneurysm developed during follow-up in the non-SAH group, and no intracranial bleeding was observed during anticoagulant treatment. Those presenting with SAH formed approximately 25% of all IADs, and 21 cases out of 22 (95%) were associated with ruptured fusiform dissecting aneurysm. This latter group displayed significantly worse outcomes: 7 died, and only 7 had modified Rankin Scale 0 to 2 at 3 months. CONCLUSIONS: Our results provide important information for clinical practice. IADs appear to polarize into 2 groups: (1) nonaneurysmatic IADs presenting without SAH that are associated with favorable outcomes and safe anticoagulant therapy; and (2) aneurysmatic IADs, characterized by SAH and poorer prognosis. Literature on IADs may have been biased toward group 2.

Cervical artery dissection in patients ≥60 years: Often painless, few mechanical triggers.

OBJECTIVE: In a cohort of patients diagnosed with cervical artery dissection (CeAD), to determine the proportion of patients aged ≥60 years and compare the frequency of characteristics (presenting symptoms, risk factors, and outcome) in patients aged <60 vs ≥60 years. METHODS: We combined data from 3 large cohorts of consecutive patients diagnosed with CeAD (i.e., Cervical Artery Dissection and Ischemic Stroke Patients-Plus consortium). We dichotomized cases into 2 groups, age ≥60 and <60 years, and compared clinical characteristics, risk factors, vascular features, and 3-month outcome between the groups. First, we performed a combined analysis of pooled individual patient data. Secondary analyses were done within each cohort and across cohorts. Crude and adjusted odds ratios (OR [95% confidence interval]) were calculated. RESULTS: Among 2,391 patients diagnosed with CeAD, we identified 177 patients (7.4%) aged ≥60 years. In this age group, cervical pain (ORadjusted 0.47 [0.33-0.66]), headache (ORadjusted 0.58 [0.42-0.79]), mechanical trigger events (ORadjusted 0.53 [0.36-0.77]), and migraine (ORadjusted 0.58 [0.39-0.85]) were less frequent than in younger patients. In turn, hypercholesterolemia (ORadjusted 1.52 [1.1-2.10]) and hypertension (ORadjusted 3.08 [2.25-4.22]) were more frequent in older patients. Key differences between age groups were confirmed in secondary analyses. In multivariable, adjusted analyses, favorable outcome (i.e., modified Rankin Scale score 0-2) was less frequent in the older age group (ORadjusted 0.45 [0.25, 0.83]). CONCLUSION: In our study population of patients diagnosed with CeAD, 1 in 14 was aged ≥60 years. In these patients, pain and mechanical triggers might be missing, rendering the diagnosis more challenging and increasing the risk of missed CeAD diagnosis in older patients.

Frequency of MELAS main mutation in a phenotype-targeted young ischemic stroke patient population.

Mitochondrial diseases, predominantly mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS), may occasionally underlie or coincide with ischemic stroke (IS) in young and middle-aged individuals. We searched for undiagnosed patients with MELAS in a target subpopulation of unselected young IS patients enrolled in the Stroke in Young Fabry Patients study (sifap1). Among the 3291 IS patients aged 18-55 years recruited to the sifap1 study at 47 centers across 14 European countries, we identified potential MELAS patients with the following phenotypic features: (a) diagnosed cardiomyopathy or (b) presence of two of the three following findings: migraine, short stature (≤165 cm for males; ≤155 cm for females), and diabetes. Identified patients' blood samples underwent analysis of the common MELAS mutation, m.3243A>G in the MTTL1 gene of mitochondrial DNA. Clinical and cerebral MRI features of the mutation carriers were reviewed. We analyzed blood samples of 238 patients (177 with cardiomyopathy) leading to identification of four previously unrecognized MELAS main mutation carrier-patients. Their clinical and MRI characteristics were within the expectation for common IS patients except for severe hearing loss in one patient and hyperintensity of the pulvinar thalami on T1-weighted MRI in another one. Genetic testing for the m.3243A>G MELAS mutation in young patients with IS based on phenotypes suggestive of mitochondrial disease identifies previously unrecognized carriers of MELAS main mutation, but does not prove MELAS as the putative cause.

Towards the genetic basis of cerebral venous thrombosis-the BEAST Consortium: a study protocol.

INTRODUCTION: Cerebral venous thrombosis (CVT) is a rare cerebrovascular condition accounting for <1% of all stroke cases and mainly affects young adults. Its genetic aetiology is not clearly elucidated. METHODS AND ANALYSIS: To better understand the genetic basis of CVT, we have established an international biobank of CVT cases, Biorepository to Establish the Aetiology of Sinovenous Thrombosis (BEAST) which aims to recruit highly phenotyped cases initially of European descent and later from other populations. To date we have recruited 745 CVT cases from 12 research centres. As an initial step, the consortium plans to undertake a genome-wide association analysis of CVT using the Illumina Infinium HumanCoreExome BeadChip to assess the association and impact of common and low-frequency genetic variants on CVT risk by using a case-control study design. Replication will be performed to confirm putative findings. Furthermore, we aim to identify interactions of genetic variants with several environmental and comorbidity factors which will likely contribute to improve the understanding of the biological mechanisms underlying this complex disease. ETHICS AND DISSEMINATION: BEAST meets all ethical standards set by local institutional review boards for each of the participating sites. The research outcomes will be published in international peer-reviewed open-access journals with high impact and visibility. The results will be presented at national and international meetings to highlight the contributions into improving the understanding of the mechanisms underlying this uncommon but important disease. This international DNA repository will become an important resource for investigators in the field of haematological and vascular disorders.

Helsinki experience on nonvitamin K oral anticoagulants for treating cervical artery dissection.

BACKGROUND: Cervical artery dissection (CeAD) patients with or without stroke are frequently treated with either antiplatelet agents or vitamin K antagonists (VKAs), but few data are reported on the use of nonvitamin K oral anticoagulants (NOACs). METHODS: Between November 2011 and January 2014, we recorded data from patients with a stroke due to vertebral (VAD) or internal carotid artery dissection (ICAD). Patients using oral anticoagulants were included in the study and were divided into two treatment groups: patients using NOACs and those using VKAs. Excellent outcome was defined on modified Rankin Scale (mRS) ≤1 at 6 months. RESULTS: Of 68 stroke patients (67% male; median age 45 [39-53]), six (8.8%; two with VAD and four with ICAD) were treated with NOACs: three with direct thrombin inhibitor dabigatran and three with direct factor Xa inhibitor rivaroxaban. National Institutes of Health Stroke Scale score at baseline was 4 (3-7) in the NOAC versus 2 (1-7) in the VKA groups. Complete recanalization at 6 months was seen in most patients in the NOAC (n = 5; 83%) and VKA (n = 34; 55%) groups. All the patients using NOACs had mRS ≤1 at 6 months and none had an intracerebral hemorrhage (ICH). In the VKA group most patients (n = 48; 77%) had mRS ≤1, one patient (1.7%) had an ICH and one died. CONCLUSIONS: In this small, consecutive single-center patient sample treating ischemic stroke patients with CeAD with NOACs did not bring up safety concerns and resulted in similar, good outcomes compared to patients using VKAs.

Common variation in PHACTR1 is associated with susceptibility to cervical artery dissection.

Cervical artery dissection (CeAD), a mural hematoma in a carotid or vertebral artery, is a major cause of ischemic stroke in young adults although relatively uncommon in the general population (incidence of 2.6/100,000 per year). Minor cervical traumas, infection, migraine and hypertension are putative risk factors, and inverse associations with obesity and hypercholesterolemia are described. No confirmed genetic susceptibility factors have been identified using candidate gene approaches. We performed genome-wide association studies (GWAS) in 1,393 CeAD cases and 14,416 controls. The rs9349379[G] allele (PHACTR1) was associated with lower CeAD risk (odds ratio (OR) = 0.75, 95% confidence interval (CI) = 0.69-0.82; P = 4.46 × 10(-10)), with confirmation in independent follow-up samples (659 CeAD cases and 2,648 controls; P = 3.91 × 10(-3); combined P = 1.00 × 10(-11)). The rs9349379[G] allele was previously shown to be associated with lower risk of migraine and increased risk of myocardial infarction. Deciphering the mechanisms underlying this pleiotropy might provide important information on the biological underpinnings of these disabling conditions.