Cerebral microvascular injuries in severe COVID-19 infection: progression of white matter hyperintensities post-infection.

A range of neuroradiological findings has been reported in patients with COVID-19, some mimicking cerebral small vessel disease (CSVD). We present a case of a man in his 50s with severe COVID-19, who was Glasgow Coma Scale 3 and tetraparetic after sedation was ceased in the intensive care unit. Return of consciousness and motor activity was slow. An MRI 1 month after debut of symptoms demonstrated white matter hyperintensities on T2-weighted Fluid Attenuated Inversion Recovery (T2-FLAIR) and many small areas with impaired diffusion in primarily supratentorial and infratentorial white matter on Diffusion-Weighted Imaging (DWI). In the following months, the patient made a remarkable clinical recovery. Despite clinical improvement, an MRI after 7 months showed that white matter hyperintensities had progressed and become confluent. Both MRIs demonstrated findings resembling CSVD, which could relate to a COVID-19-specific process affecting cerebral microvasculature.

One-Year Outcome Trajectories and Factors Associated with Functional Recovery Among Survivors of Intracerebral and Intraventricular Hemorrhage With Initial Severe Disability.

Importance: Patients who survive severe intracerebral hemorrhage (ICH) and intraventricular hemorrhage (IVH) typically have poor functional outcome in the short term and understanding of future recovery is limited. Objective: To describe 1-year recovery trajectories among ICH and IVH survivors with initial severe disability and assess the association of hospital events with long-term recovery. Design, Setting, and Participants: This post hoc analysis pooled all individual patient data from the Clot Lysis: Evaluating Accelerated Resolution of Intraventricular Hemorrhage phase 3 trial (CLEAR-III) and the Minimally Invasive Surgery Plus Alteplase for Intracerebral Hemorrhage Evacuation (MISTIE-III) phase 3 trial in multiple centers across the US, Canada, Europe, and Asia. Patients were enrolled from August 1, 2010, to September 30, 2018, with a follow-up duration of 1 year. Of 999 enrolled patients, 724 survived with a day 30 modified Rankin Scale score (mRS) of 4 to 5 after excluding 13 participants with missing day 30 mRS. An additional 9 patients were excluded because of missing 1-year mRS. The final pooled cohort included 715 patients (71.6%) with day 30 mRS 4 to 5. Data were analyzed from July 2019 to January 2022. Exposures: CLEAR-III participants randomized to intraventricular alteplase vs placebo. MISTIE-III participants randomized to stereotactic thrombolysis of hematoma vs standard medical care. Main Outcomes and Measures: Primary outcome was 1-year mRS. Patients were dichotomized into good outcome at 1 year (mRS 0 to 3) vs poor outcome at 1 year (mRS 4 to 6). Multivariable logistic regression models assessed associations between prospectively adjudicated hospital events and 1-year good outcome after adjusting for demographic characteristics, ICH and IVH severity, and trial cohort. Results: Of 715 survivors, 417 (58%) were male, and the overall mean (SD) age was 60.3 (11.7) years. Overall, 174 participants (24.3%) were Black, 491 (68.6%) were White, and 49 (6.9%) were of other races (including Asian, Native American, and Pacific Islander, consolidated owing to small numbers); 98 (13.7%) were of Hispanic ethnicity. By 1 year, 129 participants (18%) had died and 308 (43%) had achieved mRS 0 to 3. In adjusted models for the combined cohort, diabetes (adjusted odds ratio [aOR], 0.50; 95% CI, 0.26-0.96), National Institutes of Health Stroke Scale (aOR, 0.93; 95% CI, 0.90-0.96), severe leukoaraiosis (aOR, 0.30; 95% CI, 0.16-0.54), pineal gland shift (aOR, 0.87; 95% CI, 0.76-0.99]), acute ischemic stroke (aOR, 0.44; 95% CI, 0.21-0.94), gastrostomy (aOR, 0.30; 95% CI, 0.17-0.50), and persistent hydrocephalus by day 30 (aOR, 0.37; 95% CI, 0.14-0.98) were associated with lack of recovery. Resolution of ICH (aOR, 1.82; 95% CI, 1.08-3.04) and IVH (aOR, 2.19; 95% CI, 1.02-4.68) by day 30 were associated with recovery to good outcome. In the CLEAR-III model, cerebral perfusion pressure less than 60 mm Hg (aOR, 0.30; 95% CI, 0.13-0.71), sepsis (aOR, 0.05; 95% CI, 0.00-0.80), and prolonged mechanical ventilation (aOR, 0.96; 95% CI, 0.92-1.00 per day), and in MISTIE-III, need for intracranial pressure monitoring (aOR, 0.35; 95% CI, 0.12-0.98), were additional factors associated with poor outcome. Thirty-day event-based models strongly predicted 1-year outcome (area under the receiver operating characteristic curve [AUC], 0.87; 95% CI, 0.83-0.90), with significantly improved discrimination over models using baseline severity factors alone (AUC, 0.76; 95% CI, 0.71-0.80; P < .001). Conclusions and Relevance: Among survivors of severe ICH and IVH with initial poor functional outcome, more than 40% recovered to good outcome by 1 year. Hospital events were strongly associated with long-term functional recovery and may be potential targets for intervention. Avoiding early pessimistic prognostication and delaying prognostication until after treatment may improve ability to predict future recovery.

Diffusion-Weighted Imaging, MR Angiography, and Baseline Data in a Systematic Multicenter Analysis of 3,301 MRI Scans of Ischemic Stroke Patients-Neuroradiological Review Within the MRI-GENIE Study.

Background: Magnetic resonance imaging (MRI) serves as a cornerstone in defining stroke phenotype and etiological subtype through examination of ischemic stroke lesion appearance and is therefore an essential tool in linking genetic traits and stroke. Building on baseline MRI examinations from the centralized and structured radiological assessments of ischemic stroke patients in the Stroke Genetics Network, the results of the MRI-Genetics Interface Exploration (MRI-GENIE) study are described in this work. Methods: The MRI-GENIE study included patients with symptoms caused by ischemic stroke (N = 3,301) from 12 international centers. We established and used a structured reporting protocol for all assessments. Two neuroradiologists, using a blinded evaluation protocol, independently reviewed the baseline diffusion-weighted images (DWIs) and magnetic resonance angiography images to determine acute lesion and vascular occlusion characteristics. Results: In this systematic multicenter radiological analysis of clinical MRI from 3,301 acute ischemic stroke patients according to a structured prespecified protocol, we identified that anterior circulation infarcts were most prevalent (67.4%), that infarcts in the middle cerebral artery (MCA) territory were the most common, and that the majority of large artery occlusions 0 to 48 h from ictus were in the MCA territory. Multiple acute lesions in one or several vascular territories were common (11%). Of 2,238 patients with unilateral DWI lesions, 52.6% had left-sided infarct lateralization (P = 0.013 for χ2 test). Conclusions: This large-scale analysis of a multicenter MRI-based cohort of AIS patients presents a unique imaging framework facilitating the relationship between imaging and genetics for advancing the knowledge of genetic traits linked to ischemic stroke.

Relationship of White Matter Lesions with Intracerebral Hemorrhage Expansion and Functional Outcome: MISTIE II and CLEAR III.

BACKGROUND/OBJECTIVE: Intracerebral hemorrhage (ICH) patients commonly have concomitant white matter lesions (WML) which may be associated with poor outcome. We studied if WML affects hematoma expansion (HE) and post-stroke functional outcome in a post hoc analysis of patients from randomized controlled trials. METHODS: In ICH patients from the clinical trials MISTIE II and CLEAR III, WML grade on diagnostic computed tomography (dCT) scan (dCT, < 24 h after ictus) was assessed using the van Swieten scale (vSS, range 0-4). The primary outcome for HE was > 33% or > 6 mL ICH volume increase from dCT to the last pre-randomization CT (< 72 h of dCT). Secondary HE outcomes were: absolute ICH expansion, > 10.4 mL total clot volume increase, and a subgroup analysis including patients with dCT < 6 h after ictus using the primary HE definition of > 33% or > 6 mL ICH volume increase. Poor functional outcome was assessed at 180 days and defined as modified Rankin Scale (mRS) ≥ 4, with ordinal mRS as a secondary endpoint. RESULTS: Of 635 patients, 55% had WML grade 1-4 at dCT (median 2.2 h from ictus) and 13% had subsequent HE. WML at dCT did not increase the odds for primary or secondary HE endpoints (P ≥ 0.05) after adjustment for ICH volume, intraventricular hemorrhage volume, warfarin/INR > 1.5, ictus to dCT time in hours, age, diabetes mellitus, and thalamic ICH location. WML increased the odds for having poor functional outcome (mRS ≥ 4) in univariate analyses (vSS 4; OR 4.16; 95% CI 2.54-6.83; P < 0.001) which persisted in multivariable analyses after adjustment for HE and other outcome risk factors. CONCLUSIONS: Concomitant WML does not increase the odds for HE in patients with ICH but increases the odds for poor functional outcome. CLINICAL TRIAL REGISTRATION: http://www.clinicaltrials.gov trial-identifiers: NCT00224770 and NCT00784134.

Association of Apolipoprotein E With Intracerebral Hemorrhage Risk by Race/Ethnicity: A Meta-analysis.

Importance: Genetic studies of intracerebral hemorrhage (ICH) have focused mainly on white participants, but genetic risk may vary or could be concealed by differing nongenetic coexposures in nonwhite populations. Transethnic analysis of risk may clarify the role of genetics in ICH risk across populations. Objective: To evaluate associations between established differences in ICH risk by race/ethnicity and the variability in the risks of apolipoprotein E (APOE) ε4 alleles, the most potent genetic risk factor for ICH. Design, Setting, and Participants: This case-control study of primary ICH meta-analyzed the association of APOE allele status on ICH risk, applying a 2-stage clustering approach based on race/ethnicity and stratified by a contributing study. A propensity score analysis was used to model the association of APOE with the burden of hypertension across race/ethnic groups. Primary ICH cases and controls were collected from 3 hospital- and population-based studies in the United States and 8 in European sites in the International Stroke Genetic Consortium. Participants were enrolled from January 1, 1999, to December 31, 2017. Participants with secondary causes of ICH were excluded from enrollment. Controls were regionally matched within each participating study. Main Outcomes and Measures: Clinical variables were systematically obtained from structured interviews within each site. APOE genotype was centrally determined for all studies. Results: In total, 13 124 participants (7153 [54.5%] male with a median [interquartile range] age of 66 [56-76] years) were included. In white participants, APOE ε2 (odds ratio [OR], 1.49; 95% CI, 1.24-1.80; P < .001) and APOE ε4 (OR, 1.51; 95% CI, 1.23-1.85; P < .001) were associated with lobar ICH risk; however, within self-identified Hispanic and black participants, no associations were found. After propensity score matching for hypertension burden, APOE ε4 was associated with lobar ICH risk among Hispanic (OR, 1.14; 95% CI, 1.03-1.28; P = .01) but not in black (OR, 1.02; 95% CI, 0.98-1.07; P = .25) participants. APOE ε2 and ε4 did not show an association with nonlobar ICH risk in any race/ethnicity. Conclusions and Relevance: APOE ε4 and ε2 alleles appear to affect lobar ICH risk variably by race/ethnicity, associations that are confirmed in white individuals but can be shown in Hispanic individuals only when the excess burden of hypertension is propensity score-matched; further studies are needed to explore the interactions between APOE alleles and environmental exposures that vary by race/ethnicity in representative populations at risk for ICH.

Prediction of Long-Term Outcome After Intracerebral Hemorrhage Surgery.

BACKGROUND: Surgery for spontaneous primary intracerebral hemorrhage (ICH) remains controversial. Previous surgical trials have primarily focused on short-term mortality while studies on long-term functional outcome are rare. We therefore conducted this retrospective study of long-term outcome on all ICH patients who underwent craniotomy at a single neurosurgical center during a 10-year period. METHODS: We included all patients >15 years of age who underwent evacuation of spontaneous ICH at Skåne University Hospital between 2003 and 2012. Case fatality at 30 days, 1 year, and long-term follow-up (up to 10 years) were analyzed in relation to potential predictors of outcome. Long-term functional outcome was assessed in 2013 by telephone interview using the modified Rankin Scale (mRS). RESULTS: Of 229 operated patients, overall case fatality was 20% at 30 days and 31% at 1 year. For patients with supratentorial ICH, the case fatality was 16% at 30 days and 27% at 1 year, and 29% at 30 days and 41% at 1 year for patients with cerebellar ICH. The most consistent independent predictors of mortality were preictal heart disease and level of consciousness on admission. Of 185 patients with long-term functional outcome available (median follow-up 6.14 years), 44 of them (24%) had a good outcome (mRS score 0-3) and 141 (76%) were severely disabled or dead (mRS score 4-6). CONCLUSIONS: The case fatality in our study was comparatively low, but most survivors lived dependently several years after surgery. Heart disease and level of consciousness were the most consistent predictors of mortality.

17p12 Influences Hematoma Volume and Outcome in Spontaneous Intracerebral Hemorrhage.

BACKGROUND AND PURPOSE: Hematoma volume is an important determinant of clinical outcome in spontaneous intracerebral hemorrhage (ICH). We performed a genome-wide association study (GWAS) of hematoma volume with the aim of identifying novel biological pathways involved in the pathophysiology of primary brain injury in ICH. METHODS: We conducted a 2-stage (discovery and replication) case-only genome-wide association study in patients with ICH of European ancestry. We utilized the admission head computed tomography to calculate hematoma volume via semiautomated computer-assisted technique. After quality control and imputation, 7 million genetic variants were available for association testing with ICH volume, which was performed separately in lobar and nonlobar ICH cases using linear regression. Signals with P<5×10-8 were pursued in replication and tested for association with admission Glasgow coma scale and 3-month post-ICH dichotomized (0-2 versus 3-6) modified Rankin Scale using ordinal and logistic regression, respectively. RESULTS: The discovery phase included 394 ICH cases (228 lobar and 166 nonlobar) and identified 2 susceptibility loci: a genomic region on 22q13 encompassing PARVB (top single-nucleotide polymorphism rs9614326: ß, 1.84; SE, 0.32; P=4.4×10-8) for lobar ICH volume and an intergenic region overlying numerous copy number variants on 17p12 (top single-nucleotide polymorphism rs11655160: ß, 0.95; SE, 0.17; P=4.3×10-8) for nonlobar ICH volume. The replication included 240 ICH cases (71 lobar and 169 nonlobar) and corroborated the association for 17p12 (P=0.04; meta-analysis P=2.5×10-9; heterogeneity, P=0.16) but not for 22q13 (P=0.49). In multivariable analysis, rs11655160 was also associated with lower admission Glasgow coma scale (odds ratio, 0.17; P=0.004) and increased risk of poor 3-month modified Rankin Scale (odds ratio, 1.94; P=0.045). CONCLUSIONS: We identified 17p12 as a novel susceptibility risk locus for hematoma volume, clinical severity, and functional outcome in nonlobar ICH. Replication in other ethnicities and follow-up translational studies are needed to elucidate the mechanism mediating the observed association.

Genetic variants influencing elevated myeloperoxidase levels increase risk of stroke.

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 NINDS-SiGN, 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 (P < 5 × 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.

Genetic variants in CETP increase risk of intracerebral hemorrhage.

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 × 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 ∼2.85mg/dl in the Global Lipids Genetics Consortium was strongly associated with ICH risk (OR = 1.86, SE = 0.13, p = 1.39 × 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.

Applicability of Clinical Trials in an Unselected Cohort of Patients With Intracerebral Hemorrhage.

BACKGROUND AND PURPOSE: Patient selection in clinical trials on intracerebral hemorrhage (ICH) affects overall applicability of results. We estimated eligibility for completed, ongoing, and planned clinical trials in an unselected cohort of patients with ICH. METHODS: Large clinical ICH trials were identified using trial registration databases. Each trial's inclusion criteria were applied to a consecutive group of patients with ICH from the prospective hospital-based Lund Stroke Register. Survival status was obtained from the National Census Office and 90-day poor functional outcome (modified Rankin Scale ≥4) from the Swedish Stroke Register or medical files. RESULTS: Among 253 patients with ICH, estimated eligibility proportions ranged between 2% and 36% for the 11 identified clinical trials. Patients not eligible for any trial (n=96) had more intraventricular hemorrhage, lower baseline level of consciousness, higher rates of cerebellar ICH, and lower rates of lobar ICH (P≤0.001). Thirty-day case fatality for noneligible patients was 54% versus 18% among patients eligible in ≥1 trial (95% confidence interval, 44%-64% versus 13%-25%; P<0.001). Noneligible ICH patients more frequently had poor functional outcome (75% versus 48%; 95% confidence interval, 65%-83% versus 40%-56%; P<0.001). CONCLUSIONS: There is large variation in proportions of patients with ICH eligible for inclusion in clinical trials and over a third of patients with ICH are not eligible for any trial.

Intraventricular Extension of Supratentorial Intracerebral Hemorrhage: The Modified Graeb Scale Improves Outcome Prediction in Lund Stroke Register.

BACKGROUND/AIMS: The modified Graeb Scale (mGS) is a semi-quantitative method to assess the extension of intraventricular hemorrhage (IVH) in patients with intracerebral hemorrhage (ICH). The mGS has been shown to prognosticate outcome after ICH in cohorts derived from convenience samples. We evaluated the external validity of mGS in supratentorial ICH-patients from an unselected cohort. METHODS: ICH-patients were included prospectively and consecutively in Lund Stroke Register. Follow-up survival status was obtained from the National Census Office; functional outcome was obtained from the Swedish Stroke Register or medical records. Using multivariate analyses, we examined if mGS was related to 30-day survival or poor functional outcome (modified Rankin Scale ≥4) at 90 days. RESULTS: Of 198 supratentorial ICH-patients, 86 (43%) had IVH (median mGS 12, range 1-28). In multivariate regression analyses, the mGS independently predicted 30-day mortality (per point; OR 1.16; 95% CI 1.06-1.27; p = 0.002) and poor functional outcome (OR 1.11; 95% CI 1.02-1.20; p = 0.011) after ICH. In receiver-operator characteristic analysis, the addition of mGS tended to be associated with a higher prognostic accuracy for survival (area under curve 0.886 vs. not including mGS 0.812; p = 0.053). CONCLUSIONS: The mGS improves outcome prediction after supratentorial ICH beyond other previously established factors in an unselected population.

Common variation in COL4A1/COL4A2 is associated with sporadic cerebral small vessel disease.

OBJECTIVES: We hypothesized that common variants in the collagen genes COL4A1/COL4A2 are associated with sporadic forms of cerebral small vessel disease. METHODS: We conducted meta-analyses of existing genotype data among individuals of European ancestry to determine associations of 1,070 common single nucleotide polymorphisms (SNPs) in the COL4A1/COL4A2 genomic region with the following: intracerebral hemorrhage and its subtypes (deep, lobar) (1,545 cases, 1,485 controls); ischemic stroke and its subtypes (cardioembolic, large vessel disease, lacunar) (12,389 cases, 62,004 controls); and white matter hyperintensities (2,733 individuals with ischemic stroke and 9,361 from population-based cohorts with brain MRI data). We calculated a statistical significance threshold that accounted for multiple testing and linkage disequilibrium between SNPs (p < 0.000084). RESULTS: Three intronic SNPs in COL4A2 were significantly associated with deep intracerebral hemorrhage (lead SNP odds ratio [OR] 1.29, 95% confidence interval [CI] 1.14-1.46, p = 0.00003; r(2) > 0.9 between SNPs). Although SNPs associated with deep intracerebral hemorrhage did not reach our significance threshold for association with lacunar ischemic stroke (lead SNP OR 1.10, 95% CI 1.03-1.18, p = 0.0073), and with white matter hyperintensity volume in symptomatic ischemic stroke patients (lead SNP OR 1.07, 95% CI 1.01-1.13, p = 0.016), the direction of association was the same. There was no convincing evidence of association with white matter hyperintensities in population-based studies or with non-small vessel disease cerebrovascular phenotypes. CONCLUSIONS: Our results indicate an association between common variation in the COL4A2 gene and symptomatic small vessel disease, particularly deep intracerebral hemorrhage. These findings merit replication studies, including in ethnic groups of non-European ancestry.

Meta-analysis in more than 17,900 cases of ischemic stroke reveals a novel association at 12q24.12.

OBJECTIVES: To perform a genome-wide association study (GWAS) using the Immunochip array in 3,420 cases of ischemic stroke and 6,821 controls, followed by a meta-analysis with data from more than 14,000 additional ischemic stroke cases. METHODS: Using the Immunochip, we genotyped 3,420 ischemic stroke cases and 6,821 controls. After imputation we meta-analyzed the results with imputed GWAS data from 3,548 cases and 5,972 controls recruited from the ischemic stroke WTCCC2 study, and with summary statistics from a further 8,480 cases and 56,032 controls in the METASTROKE consortium. A final in silico "look-up" of 2 single nucleotide polymorphisms in 2,522 cases and 1,899 controls was performed. Associations were also examined in 1,088 cases with intracerebral hemorrhage and 1,102 controls. RESULTS: In an overall analysis of 17,970 cases of ischemic stroke and 70,764 controls, we identified a novel association on chromosome 12q24 (rs10744777, odds ratio [OR] 1.10 [1.07-1.13], p = 7.12 × 10(-11)) with ischemic stroke. The association was with all ischemic stroke rather than an individual stroke subtype, with similar effect sizes seen in different stroke subtypes. There was no association with intracerebral hemorrhage (OR 1.03 [0.90-1.17], p = 0.695). CONCLUSION: Our results show, for the first time, a genetic risk locus associated with ischemic stroke as a whole, rather than in a subtype-specific manner. This finding was not associated with intracerebral hemorrhage.

Meta-analysis of genome-wide association studies identifies 1q22 as a susceptibility locus for intracerebral hemorrhage.

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.

Long term (13 years) prognosis after primary intracerebral haemorrhage: a prospective population based study of long term mortality, prognostic factors and causes of death.

INTRODUCTION: Many studies have focused on short term mortality after primary intracerebral haemorrhage (ICH) whereas long term prognosis and causes of death have been less studied. We therefore examined these issues in a population based cohort of 1 year ICH survivors. METHODS: ICH patients in a defined Swedish population (1.14 million inhabitants) were prospectively registered during 1996. Patients surviving 1 year after ICH onset were followed-up regarding survival status and cause of death until December 2009 using data from the National Census Office and the National Cause of Death Register. Patient prognosis was also compared with the general population using official Swedish mortality data. Clinical and radiological prognostic factors were evaluated. RESULTS: Of 323 patients with ICH, 172 (53%) survived after 1 year, 127 (39%) after 5 years and 57 (18%) after 13 years. Mortality of the 172, 1 year survivors (mean age 67.7 years at ICH) persistently exceeded expected mortality; 13 years post ictus survival was only 34% compared with 61% in the general population. Of 115 deaths among the 172, 1 year survivors, 36% were from cerebrovascular disease and 19% from ischaemic heart disease. Independent risk factors for death among 1 year survivors were age (HR 1.08 per year; 95% CI 1.06 to 1.10; p<0.001), diabetes mellitus at baseline (HR 2.10; 95% CI 1.18 to 3.74; p=0.012) and anticoagulant therapy (HR 1.99; 95% CI 1.12 to 3.53; p=0.018) at ICH onset. CONCLUSIONS: One year survivors after ICH had a substantial and persisting excess mortality compared with the general population. Major causes of death were stroke and ischaemic heart disease.

Heritability estimates identify a substantial genetic contribution to risk and outcome of intracerebral hemorrhage.

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-APOEloci 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.

Common variants within oxidative phosphorylation genes influence risk of ischemic stroke and intracerebral hemorrhage.

BACKGROUND AND PURPOSE: Previous studies demonstrated association between mitochondrial DNA variants and ischemic stroke (IS). We investigated whether variants within a larger set of oxidative phosphorylation (OXPHOS) genes encoded by both autosomal and mitochondrial DNA were associated with risk of IS and, based on our results, extended our investigation to intracerebral hemorrhage (ICH). METHODS: This association study used a discovery cohort of 1643 individuals, a validation cohort of 2432 individuals for IS, and an extension cohort of 1476 individuals for ICH. Gene-set enrichment analysis was performed on all structural OXPHOS genes, as well as genes contributing to individual respiratory complexes. Gene-sets passing gene-set enrichment analysis were tested by constructing genetic scores using common variants residing within each gene. Associations between each variant and IS that emerged in the discovery cohort were examined in validation and extension cohorts. RESULTS: IS was associated with genetic risk scores in OXPHOS as a whole (odds ratio [OR], 1.17; P=0.008) and complex I (OR, 1.06; P=0.050). Among IS subtypes, small vessel stroke showed association with OXPHOS (OR, 1.16; P=0.007), complex I (OR, 1.13; P=0.027), and complex IV (OR, 1.14; P=0.018). To further explore this small vessel association, we extended our analysis to ICH, revealing association between deep hemispheric ICH and complex IV (OR, 1.08; P=0.008). CONCLUSIONS: This pathway analysis demonstrates association between common genetic variants within OXPHOS genes and stroke. The associations for small vessel stroke and deep ICH suggest that genetic variation in OXPHOS influences small vessel pathobiology. Further studies are needed to identify culprit genetic variants and assess their functional consequences.

Burden of risk alleles for hypertension increases risk of intracerebral hemorrhage.

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. CONCLUSIONS: Increasing numbers of high blood pressure-related alleles are associated with increased risk of deep ICH as well as with clinically identified HTN.

APOE genotype and extent of bleeding and outcome in lobar intracerebral haemorrhage: a genetic association study.

BACKGROUND: Carriers of APOE ε2 and ε4 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 ε2 and ε4 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 ε4 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 ε2 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 ε2 increased haematoma size by a mean of 5·3 mL (95% CI 4·7-5·9; p=0·004). Carriers of APOE ε2 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 ε4 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 ε2 allele might have a role in the severity and clinical course of lobar ICH. Screening of patients who have ICH to identify the ε2 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.

Variants at APOE influence risk of deep and lobar intracerebral hemorrhage.

OBJECTIVE: Prior studies investigating the association between APOE alleles ε2/ε4 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 ε2 and ε4. 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 ε2 and ε4 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 × 10(-10); and OR = 2.20, 95%CI = 1.85-2.63, p = 2.4 × 10(-11), respectively). Restriction of analysis to definite/probable cerebral amyloid angiopathy ICH uncovered a stronger effect. Allele ε4 was also associated with increased risk for deep ICH (OR = 1.21, 95% CI = 1.08-1.36, p = 2.6 × 10(-4)). Risk prediction evaluation identified the additive model as best for describing the effect of APOE genotypes. INTERPRETATION: APOE ε2 and ε4 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 ε4 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.