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Aim of the study. The 4C Mortality Score was created to predict mortality in hospitalised patients with COVID-19 and has to date been evaluated only in respiratory system disorders. The aim of this study was to investigate its application in patients with COVID-19-associated acute ischaemic stroke (AIS). Clinical rationale for study. COVID-19 is a risk factor for AIS. COVID-19-associated AIS results in higher mortality and worse functional outcome. Predictors of functional outcome in COVID-19-associated AIS are required. Materials and methods. This was a retrospective observational study of patients with AIS hospitalised in seven neurological wards in Malopolska Voivodship (Poland) between August and December 2020. We gathered data concerning the patients’ age, sex, presence of cardiovascular risk factors, type of treatment received, and the presence of stroke-associated infections (including pneumonia, urinary tract infection and infection of unknown source). We calculated 4C Mortality Score at stroke onset, and investigated whether there was a correlation with neurological deficit measured using the National Health Institute Stroke Scale (NIHSS) and functional outcome assessed using the modified Rankin Scale (mRS) at discharge. Results. The study included 52 patients with COVID-19-associated AIS. The 4C Mortality Score at stroke onset correlated with mRS (rs = 0.565, p < 0.01) at discharge. There was also a statistically significant difference in the mean 4C Mortality Score between patients who died and patients who survived the stroke (13.08 ± 2.71 vs. 9.85 ± 3.47, p = 0.04). Conclusions and clinical implications. 4C Mortality Score predicts functional outcome at discharge in COVID-19-associated AIS patients.

Purpose: According to guidelines, to shorten the treatment window, acute ischaemic stroke (AIS) treatment by intravenous thrombolysis (IVT) can be done based on the results of head computed tomography (CT) without contrast. The impact of large vessel occlusion (LVO) on computed tomography angiography (CTA) in stroke prognosis in patients treated IVT or IVT and mechanical thrombectomy (MT), where indicated, has not yet been studied systematically. We investigated the influence of LVO in consecutive AIS patients on haemorrhagic transformation (HT) on CT 24 h after treatment, mRS < 2 on discharge (unfavourable outcome), and in-hospital mortality. Material and methods: We analysed several parameters within 24 h after AIS: demographics, risk factors, mRS score pre-stroke, NIHSS upon admission and 24 h later, several clinical and biochemical parameters, and chronic treatment. Results: We registered 1209 patients, of whom 362 (29.9%) received IVT and 108 had MT, where indicated. Admission CTA showed LVO in 197 patients (54.4%). Multivariate regression analysis showed that the presence of LVO and lower delta NIHSS (NIHSS on admission minus NIHSS 24 hours later) were independent parameters affecting HT risk. Multivariate analysis showed that the presence LVO and also older age, female sex, lower delta NIHSS, HT, stroke-associated infection, CRP levels ≥ 10 mg/L, and higher WBC count affected unfavourable outcome on discharge. LVO did not affect in-hospital mortality. Conclusions: LVO in AIS patients treated by IVT or IVT and MT affects the risk of HT and unfavourable short-term outcome but not in-hospital mortality.

Objective Observational studies point to an inverse correlation between low‐density lipoprotein (LDL) cholesterol levels and risk of intracerebral hemorrhage (ICH), but it remains unclear whether this association is causal. We tested the hypothesis that genetically elevated LDL is associated with reduced risk of ICH. Methods We constructed one polygenic risk score (PRS) per lipid trait (total cholesterol, LDL, high‐density lipoprotein [HDL], and triglycerides) using independent genomewide significant single nucleotide polymorphisms (SNPs) for each trait. We used data from 316,428 individuals enrolled in the UK Biobank to estimate the effect of each PRS on its corresponding trait, and data from 1,286 ICH cases and 1,261 matched controls to estimate the effect of each PRS on ICH risk. We used these estimates to conduct Mendelian Randomization (MR) analyses. Results We identified 410, 339, 393, and 317 lipid‐related SNPs for total cholesterol, LDL, HDL, and triglycerides, respectively. All four PRSs were strongly associated with their corresponding trait (all p 0.05). MR analyses indicated that 1mmol/L (38.67mg/dL) increase of genetically instrumented total and LDL cholesterol were associated with 23% (OR = 0.77; 95% CI = 0.65–0.98; p = 0.03) and 41% lower risks of ICH (OR = 0.59; 95% CI = 0.42–0.82; p = 0.002), respectively. Interpretation Genetically elevated LDL levels were associated with lower risk of ICH, providing support for a potential causal role of LDL cholesterol in ICH.

The impact of contracting stroke-associate infection (SAI) that requires antibiotic treatment after an acute ischemic stroke (AIS) treated with alteplase remains unclear. We studied the profiles of SAI in patients with AIS treated with alteplase toward identifying predictive factors and prognostic implications at 90 days post-stroke.We analyzed 33 parameters readily available within 24 hours after AIS: demographics, risk factors, and several clinical and biochemical parameters. Outcome measures were mRS ≤ 2 and mortality 90 days post-stroke.83 (23.6%) of 352 patients developed SAI. Multivariate logistic regression analysis showed that atrial fibrillation, mRS above 0 pre-stroke, lower delta NIHSS (the difference between NIHSS score measured upon admission and 24 hours after later), CRP≥10 mg/L, and elevated WBC count affected SAI risk (model including CRP levels and WBC count) and atrial fibrillation, mRS above 0 pre-stroke, lower delta NIHSS, HT, and elevated fibrinogen levels affected SAI risk (model excluding CRP levels and WBC count). 231 patients (74.1%) had mRS ≤ 2 at day 90. Multivariate logistic regression analysis showed that younger age, no hypertension, mRS=0 pre-stroke, higher delta NIHSS, no HT, no SAI, and CRP10 mg/L, were associated with mRS≤2 at day 90. 54 (15.3%) patients died within 90 days. Multivariate logistic regression analysis showed that pre-stroke mRS0, lower delta NIHSS, HT, CRP≥10 mg/L, lower triglyceride levels affected the risk of death within 90 days.Several markers available within 24 hours post-stroke were predictive of SAI that requires antibiotic treatment. SAI affects long-term outcome but not mortality.

Little is known about the prognostic role of fasting glucose after mechanical thrombectomy (MT).We investigated whether fasting glucose on the next day after MT was associated with long-term outcome in acute ischemic stroke patients according to diabetes.We retrospectively analyzed 181 consecutive patients with acute anterior circulation ischemic stroke who underwent MT in 2 comprehensive stroke centers in Poland. Glucose levels were evaluated on admission and on the next day after MT. Fasting hyperglycemia (FHG) was defined as the glucose level above 5.5 mmol/L. Unfavorable outcome was defined as modified Rankin scale (mRS) of 3-6 at day 90 from stroke onset.Patients with FHG had higher mRS at 3-month follow-up compared with those without FHG (3.71 ± 2.56 versus 1.87 ± 2.22, P.001). In the subgroup analyses, FHG was associated with poor neurological outcome in the group without diabetes (3.74 ± 2.52 versus 1.81 ± 3.74, P.001) but not with diabetes (3.64 ± 2.67 versus 2.30 ± 3.74, P= .11). Patients without diabetes who had FHG were older, had higher glucose on admission, higher prevalence of atrial fibrillation, cardioembolic stroke etiology and bleeding brain complications compared with the group with normal fasting glucose. After adjustment for potential confounders, fasting glucose (odds ratio [OR] 1.46; 95% CI 1.19-1.79, P.001), age (OR 1.06; 95% CI 1.02-1.10, P = .001), successful reperfusion (OR 0.09; 95% CI 0.04-0.22, P.001) and baseline NIHSS score (OR 1.18; 95% CI 1.08-1.29, P.001) were predictors of mRS 3-6 at 3-month follow-up in the whole group. In the subgroup without diabetes, fasting glucose (OR 1.57; 95% CI 1.17-2.11, P = .002), age (OR 1.05; 95% CI 1.01-1.08, P = .008), successful reperfusion (OR 0.11; 95% CI 0.04-0.30, P.001) and baseline NIHSS score (OR 1.14; 95% CI 1.04-1.26, P = .011) were independent predictors of unfavorable 3-month outcome.Fasting glucose on the next day after MT in patients with acute ischemic stroke is an independent risk factor for worse 3-month outcome.

Intracerebral hemorrhage (ICH) is the stroke subtype with the worst prognosis and has no established acute treatment. ICH is classified as lobar or nonlobar based on the location of ruptured blood vessels within the brain. These different locations also signal different underlying vascular pathologies. Heritability estimates indicate a substantial genetic contribution to risk of ICH in both locations. We report a genome-wide association study of this condition that meta-analyzed data from six studies that enrolled individuals of European ancestry. Case subjects were ascertained by neurologists blinded to genotype data and classified as lobar or nonlobar based on brain computed tomography. ICH-free control subjects were sampled from ambulatory clinics or random digit dialing. Replication of signals identified in the discovery cohort with p < 1 × 10(-6) was pursued in an independent multiethnic sample utilizing both direct and genome-wide genotyping. The discovery phase included a case cohort of 1,545 individuals (664 lobar and 881 nonlobar cases) and a control cohort of 1,481 individuals and identified two susceptibility loci: for lobar ICH, chromosomal region 12q21.1 (rs11179580, odds ratio [OR] = 1.56, p = 7.0 × 10(-8)); and for nonlobar ICH, chromosomal region 1q22 (rs2984613, OR = 1.44, p = 1.6 × 10(-8)). The replication included a case cohort of 1,681 individuals (484 lobar and 1,194 nonlobar cases) and a control cohort of 2,261 individuals and corroborated the association for 1q22 (p = 6.5 × 10(-4); meta-analysis p = 2.2 × 10(-10)) but not for 12q21.1 (p = 0.55; meta-analysis p = 2.6 × 10(-5)). These results demonstrate biological heterogeneity across ICH subtypes and highlight the importance of ascertaining ICH cases accordingly.

Primary intracerebral haemorrhage and lacunar ischaemic stroke are acute manifestations of progressive cerebral microvascular disease. Current paradigms suggest atherosclerosis is a chronic, dynamic, inflammatory condition precipitated in response to endothelial injury from various environmental challenges. Myeloperoxidase plays a central role in initiation and progression of vascular inflammation, but prior studies linking myeloperoxidase with stroke risk have been inconclusive. We hypothesized that genetic determinants of myeloperoxidase levels influence the development of vascular instability, leading to increased primary intracerebral haemorrhage and lacunar stroke risk. We used a discovery cohort of 1409 primary intracerebral haemorrhage cases and 1624 controls from three studies, an extension cohort of 12 577 ischaemic stroke cases and 25 643 controls from NINDSSiGN, and a validation cohort of 10 307 ischaemic stroke cases and 29 326 controls from METASTROKE Consortium with genome-wide genotyping to test this hypothesis. A genetic risk score reflecting elevated myeloperoxidase levels was constructed from 15 common single nucleotide polymorphisms identified from prior genome-wide studies of circulating myeloperoxidase levels (P55 - 10 6). This genetic risk score was used as the independent variable in multivariable regression models for association with primary intracerebral haemorrhage and ischaemic stroke subtypes. We used fixed effects meta-analyses to pool estimates across studies. We also used Cox regression models in a prospective cohort of 174 primary intracerebral haemorrhage survivors for association with intracerebral haemorrhage recurrence. We present effects of myeloperoxidase elevating single nucleotide polymorphisms on stroke risk per risk allele, corresponding to a one allele increase in the myeloperoxidase increasing genetic risk score. Genetic determinants of elevated circulating myeloperoxidase levels were associated with both primary intracerebral haemorrhage risk (odds ratio, 1.07, P = 0.04) and recurrent intracerebral haemorrhage risk (hazards ratio, 1.45, P = 0.006). In analysis of ischaemic stroke subtypes, the myeloperoxidase increasing genetic risk score was strongly associated with lacunar subtype only (odds ratio, 1.05, P = 0.0012). These results, demonstrating that common genetic variants that increase myeloperoxidase levels increase risk of primary intracerebral haemorrhage and lacunar stroke, directly implicate the myeloperoxidase pathway in the pathogenesis of cerebral small vessel disease. Because genetic variants are not influenced by environmental exposures, these results provide new support for a causal rather than bystander role for myeloperoxidase in the progression of cerebrovascular disease. Furthermore, these results support a rationale for chronic inflammation as a potential modifiable stroke risk mechanism, and suggest that immune-targeted therapies could be useful for treatment and prevention of cerebrovascular disease. (Less)

Objective: Prior studies investigating the association between APOE alleles epsilon 2/epsilon 4 and risk of intracerebral hemorrhage (ICH) have been inconsistent and limited to small sample sizes, and did not account for confounding by population stratification or determine which genetic risk model was best applied. Methods: We performed a large-scale genetic association study of 2189 ICH cases and 4041 controls from 7 cohorts, which were analyzed using additive models for epsilon 2 and epsilon 4. Results were subsequently meta-analyzed using a random effects model. A proportion of the individuals (322 cases, 357 controls) had available genome-wide data to adjust for population stratification. Results: Alleles epsilon 2 and epsilon 4 were associated with lobar ICH at genome-wide significance levels (odds ratio [OR] = 1.82, 95% confidence interval [CI] = 1.50-2.23, p = 6.6 x 10(-10); and OR = 2.20, 95%CI = 1.85-2.63, p = 2.4 x 10(-11), respectively). Restriction of analysis to definite/probable cerebral amyloid angiopathy ICH uncovered a stronger effect. Allele epsilon 4 was also associated with increased risk for deep ICH (OR = 1.21, 95% CI = 1.08-1.36, p = 2.6 x 10(-4)). Risk prediction evaluation identified the additive model as best for describing the effect of APOE genotypes. Interpretation: APOE epsilon 2 and epsilon 4 are independent risk factors for lobar ICH, consistent with their known associations with amyloid biology. In addition, we present preliminary findings on a novel association between APOE epsilon 4 and deep ICH. Finally, we demonstrate that an additive model for these APOE variants is superior to other forms of genetic risk modeling previously applied. ANN NEUROL 2010;68:934-943

Contains fulltext : 167830.pdf (Publisher’s version ) (Open Access) OBJECTIVE: In observational epidemiologic studies, higher plasma high-density lipoprotein cholesterol (HDL-C) has been associated with increased risk of intracerebral hemorrhage (ICH). DNA sequence variants that decrease cholesteryl ester transfer protein (CETP) gene activity increase plasma HDL-C; as such, medicines that inhibit CETP and raise HDL-C are in clinical development. Here, we test the hypothesis that CETP DNA sequence variants associated with higher HDL-C also increase risk for ICH. METHODS: We performed 2 candidate-gene analyses of CETP. First, we tested individual CETP variants in a discovery cohort of 1,149 ICH cases and 1,238 controls from 3 studies, followed by replication in 1,625 cases and 1,845 controls from 5 studies. Second, we constructed a genetic risk score comprised of 7 independent variants at the CETP locus and tested this score for association with HDL-C as well as ICH risk. RESULTS: Twelve variants within CETP demonstrated nominal association with ICH, with the strongest association at the rs173539 locus (odds ratio [OR] = 1.25, standard error [SE] = 0.06, p = 6.0 x 10-4 ) with no heterogeneity across studies (I2 = 0%). This association was replicated in patients of European ancestry (p = 0.03). A genetic score of CETP variants found to increase HDL-C by approximately 2.85mg/dl in the Global Lipids Genetics Consortium was strongly associated with ICH risk (OR = 1.86, SE = 0.13, p = 1.39 x 10-6 ). INTERPRETATION: Genetic variants in CETP associated with increased HDL-C raise the risk of ICH. Given ongoing therapeutic development in CETP inhibition and other HDL-raising strategies, further exploration of potential adverse cerebrovascular outcomes may be warranted. Ann Neurol 2016;80:730-740.

Background and purpose Spontaneous intracerebral haemorrhage (ICH) is the most fatal form of stroke with the highest morbidity and disability rate of all stroke types. Recent data suggest that the genetic background has a sizeable and mostly undiscovered effect on the brain haemorrhage risk. Since the coagulation system is crucial to ICH pathology, we studied the significance of the FGA Thr312Ala polymorphism in two European populations. Materials and methods We genotyped 550 and 224 controls as well as 261 and 242 stroke patients in Polish and Greek populations, respectively. The ICH diagnosis was confirmed by computed tomography. The FGA Thr312Ala polymorphism was analysed using real-time polymorphism chain reaction. Results Both crude and multivariable regression analyses showed that the studied polymorphism is a protective factor in the Polish population under the dominant and additive models of inheritance. Those results did not replicate in the Greek population. The meta-analysis of results from the Polish and the Greek populations proved that FGA Thr312Ala polymorphism affects the risk of ICH in the dominant model of inheritance. Conclusions The FGA Thr312Ala polymorphism affects a risk for ICH in the Polish but not in the Greek population. An advanced meta-analysis of well-designed studies with a significant number of cases might provide useful information of novel polymorphisms, including the FGA Thr312Ala polymorphism, and their role in ICH pathology.

Background and purpose Ischaemic stroke is considered to be multifactorial and interactions between environmental and genetic factors play an important role. Although vascular risk factors are well known, the genetic ones are still undiscovered. In the present study, we assessed the significance of the β-fibrinogen –455G/A gene polymorphism and the risk of ischaemic stroke in a Polish population. Material and methods 426 ischaemic stroke patients classified according to stroke aetiologies (small vessel disease, large vessel disease or cardioembolic stroke) and 234 controls were included in the study. The association of the β-fibrinogen genotypes with ischaemic stroke was tested using logistic regression analysis under dominant, recessive or additive models of inheritance. Results The allele and genotype distributions of the β-fibrinogen –455G/A gene polymorphism did not differ significantly between patients and controls (patients: G – 75%, GG – 56.6%, GA – 36.8%, AA – 6.6%; controls: G – 73.7%, GG – 57.3%, GA – 32.9%, AA – 9.8%; p > 0.05, χ 2 ). In addition, logistic regression analysis adjusted for the known risk factors, i.e. hypertension, ischaemic heart disease, myocardial infarction, hypercholesterolaemia, diabetes mellitus and smoking, did not show a role of the studied polymorphism in ischaemic stroke. Conclusions The β-fibrinogen –455G/A gene polymorphism is not a risk factor for ischaemic stroke in a Polish population.

Background and Purpose— Previous studies suggest that genetic variation plays a substantial role in occurrence and evolution of intracerebral hemorrhage (ICH). Genetic contribution to disease can be determined by calculating heritability using family-based data, but such an approach is impractical for ICH because of lack of large pedigree-based studies. However, a novel analytic tool based on genome-wide data allows heritability estimation from unrelated subjects. We sought to apply this method to provide heritability estimates for ICH risk, severity, and outcome. Methods— We analyzed genome-wide genotype data for 791 ICH cases and 876 controls, and determined heritability as the proportion of variation in phenotype attributable to captured genetic variants. Contribution to heritability was separately estimated for the APOE (encoding apolipoprotein E) gene, an established genetic risk factor, and for the rest of the genome. Analyzed phenotypes included ICH risk, admission hematoma volume, and 90-day mortality. Results— ICH risk heritability was estimated at 29% (SE, 11%) for non- APOE loci and at 15% (SE, 10%) for APOE . Heritability for 90-day ICH mortality was 41% for non- APOE loci and 10% (SE, 9%) for APOE . Genetic influence on hematoma volume was also substantial: admission volume heritability was estimated at 60% (SE, 70%) for non- APOE loci and at 12% (SE, 4%) for APOE . Conclusions— Genetic variation plays a substantial role in ICH risk, outcome, and hematoma volume. Previously reported risk variants account for only a portion of inherited genetic influence on ICH pathophysiology, pointing to additional loci yet to be identified.

Background and Purpose— Fibrin clot formation is important in acute intracerebral hemorrhage (ICH). We investigated plasma fibrin clot characteristics in acute ICH compared with acute ischemic stroke (IS) and nonstroke conditions. Methods— In the 3 studied groups, we analyzed plasma fibrin clot phenotype and its association with clinical stroke presentation. Results— Compared with controls, in patients with acute strokes, fibrin clots presented with lower clot permeability, longer lysis time, and higher maximum clot absorbance (for all, P P P d -dimers released from clots, whereas initial hematoma volume correlated with lag phase of fibrin formation on turbidimetry and compaction ( P Conclusions— In both types of acute strokes, fibrin clot properties are altered: denser fibrin clots are relatively resistant to lysis. In acute ICH, fibrin clots are more susceptible to tissue plasminogen activator–mediated lysis compared with in IS, which might affect ICH pathogenesis.

Objective: Accumulated evidence suggests that a variant within the CR1 gene (single nucleotide polymorphism rs6656401), known to increase risk for Alzheimer disease (AD), influences β-amyloid (Aβ) deposition in brain tissue. Given the biologic overlap between AD and cerebral amyloid angiopathy (CAA), a leading cause of intracerebral hemorrhage (ICH) in elderly individuals, we investigated whether rs6656401 increases the risk of CAA-related ICH and influences vascular Aβ deposition. Methods: We performed a case-control genetic association study of 89 individuals with CAA-related ICH and 280 individuals with ICH unrelated to CAA and compared them with 324 ICH-free control subjects. We also investigated the effect of rs6656401 on risk of recurrent CAA-ICH in a prospective longitudinal cohort of ICH survivors. Finally, association with severity of histopathologic CAA was investigated in 544 autopsy specimens from 2 longitudinal studies of aging. Results: rs6656401 was associated with CAA-ICH (odds ratio [OR] = 1.61, 95% confidence interval [CI] 1.19–2.17, p = 8.0 × 10 −4 ) as well as with risk of recurrent CAA-ICH (hazard ratio = 1.35, 95% CI 1.04–1.76, p = 0.024). Genotype at rs6656401 was also associated with severity of CAA pathology at autopsy (OR = 1.34, 95% CI 1.05–1.71, p = 0.009). Adjustment for parenchymal amyloid burden did not cancel this effect, suggesting that, despite the correlation between parenchymal and vascular amyloid pathology, CR1 acts independently on both processes, thus increasing risk of both AD and CAA. Conclusion: The CR1 variant rs6656401 influences risk and recurrence of CAA-ICH, as well as the severity of vascular amyloid deposition.

Background and Purpose— Genetic variation influences risk of intracerebral hemorrhage (ICH). Hypertension (HTN) is a potent risk factor for ICH and several common genetic variants (single nucleotide polymorphisms [SNPs]) associated with blood pressure levels have been identified. We sought to determine whether the cumulative burden of blood pressure-related SNPs is associated with risk of ICH and pre-ICH diagnosis of HTN. Methods— We conducted a prospective multicenter case–control study in 2272 subjects of European ancestry (1025 cases and 1247 control subjects). Thirty-nine SNPs reported to be associated with blood pressure levels were identified from the National Human Genome Research Institute genomewide association study catalog. Single-SNP association analyses were performed for the outcomes ICH and pre-ICH HTN. Subsequently, weighted and unweighted genetic risk scores were constructed using these SNPs and entered as the independent variable in logistic regression models with ICH and pre-ICH HTN as the dependent variables. Results— No single SNP was associated with either ICH or pre-ICH HTN. The blood pressure-based unweighted genetic risk score was associated with risk of ICH (OR, 1.11; 95% CI, 1.02–1.21; P =0.01) and the subset of ICH in deep regions (OR, 1.18; 95% CI, 1.07–1.30; P =0.001), but not with the subset of lobar ICH. The score was associated with a history of HTN among control subjects (OR, 1.17; 95% CI, 1.04–1.31; P =0.009) and ICH cases (OR, 1.15; 95% CI, 1.01–1.31; P =0.04). Similar results were obtained when using a weighted score. Conclusion— Increasing numbers of high blood pressure-related alleles are associated with increased risk of deep ICH as well as with clinically identified HTN.

Summary Background Carriers of APOE ɛ2 and ɛ4 have an increased risk of intracerebral haemorrhage (ICH) in lobar regions, presumably because of the effects of these gene variants on risk of cerebral amyloid angiopathy. We aimed to assess whether these variants also associate with severity of ICH, in terms of haematoma volume at presentation and subsequent outcome. Methods We investigated the association of APOE ɛ2 and ɛ4 with ICH volume and outcomes in patients with primary ICH in three phases: a discovery phase of 865 individuals of European ancestry from the Genetics of Cerebral Hemorrhage on Anticoagulation study, and replication phases of 946 Europeans (replication 1) and 214 African-Americans (replication 2) from an additional six studies. We also assessed the association of APOE variants with ICH volume and outcomes in meta-analyses of results from all three phases, and the association of APOE ɛ4 with mortality in a further meta-analysis including data from previous reports. Admission ICH volume was quantified on CT scan. We assessed functional outcome (modified Rankin scale score 3–6) and mortality at 90 days. We used linear regression to establish the effect of genotype on haematoma volume and logistic regression to assess the effect on outcome from ICH. Findings For patients with lobar ICH, carriers of the APOE ɛ2 allele had larger ICH volumes than did non-carriers in the discovery phase (p=2·5×10 −5 ), in both replication phases (p=0·008 in Europeans and p=0·016 in African-Americans), and in the meta-analysis (p=3·2×10 −8 ). In the meta-analysis, each copy of APOE ɛ2 increased haematoma size by a mean of 5·3 mL (95% CI 4·7–5·9; p=0·004). Carriers of APOE ɛ2 had increased mortality (odds ratio [OR] 1·50, 95% CI 1·23–1·82; p=2·45×10 −5 ) and poorer functional outcomes (modified Rankin scale score 3–6; 1·52, 1·25–1·85; p=1·74×10 −5 ) compared with non-carriers after lobar ICH. APOE ɛ4 was not associated with lobar ICH volume, functional outcome, or mortality in the discovery phase, replication phases, or meta-analysis of these three phases; in our further meta-analysis of 2194 patients, this variant did not increase risk of mortality (1·08, 0·86–1·36; p=0·52). APOE allele variants were not associated with deep ICH volume, functional outcome, or mortality. Interpretation Vasculopathic changes associated with the APOE ɛ2 allele might have a role in the severity and clinical course of lobar ICH. Screening of patients who have ICH to identify the ɛ2 variant might allow identification of those at increased risk of mortality and poor functional outcomes. Funding US National Institutes of Health-National Institute of Neurological Disorders and Stroke, Keane Stroke Genetics Research Fund, Edward and Maybeth Sonn Research Fund, and US National Center for Research Resources.

Objective: Rare mitochondrial mutations cause neurologic disease, including ischemic stroke and MRI white matter changes. We investigated whether common mitochondrial genetic variants influence risk of sporadic ischemic stroke and, in patients with stroke, the volume of white matter hyperintensity (WMHV). Methods: In this multicenter, mitochondrial genome-wide association study (GWAS), 2284 ischemic stroke cases and 1728 controls from the International Stroke Genetics Consortium were genotyped for 64 mitochondrial single nucleotide polymorphisms (SNPs). Imputation resulted in 144 SNPs, which were tested in each cohort and in meta-analysis for ischemic stroke association. A genetic score of all mitochondrial variants was also tested in association with ischemic stroke. Results: No individual SNP reached adjusted significance in meta-analysis. A genetic score comprised of the summation of contributions from individual variants across the mitochondrial genome showed association with ischemic stroke in meta-analysis (odds ratio [OR] ¼ 1.13, p < 0.0001) with minimal heterogeneity (I 2 ¼ 0.00). This ischemic stroke score was robust to permutation, and was also associated with WMHV in 792 nested case individuals with ischemic stroke (p ¼ 0.037). Interpretation: In this mitochondrial GWAS of ischemic stroke, a genetic score comprised of the sum of all common variants in the mitochondrial genome showed association with ischemic stroke. In an independent analysis of a related trait, this same score correlated with WMHV in stroke cases. Despite this aggregate association, no individual variant reached significance. Substantially larger studies will be required to identify precise sequence variants influencing cerebrovascular disease. ANN NEUROL 2010;00:000–000