Impaired endothelial function in patients with cryptogenic stroke and patent foramen ovale is not affected by closure.

INTRODUCTION: Patent foramen ovale (PFO) is associated with cryptogenic stroke (CS) and migraine with aura (MA). Endothelial dysfunction (ED) is a risk factor for development of cardiovascular disease, but might also be involved in migraine pathophysiology. Short-term worsening of migraine has been described after closure of PFO. We evaluated endothelial function in patients with CS and PFO, before and after closure of PFO, and in patients with migraine, whether changes in endothelial function was related to a change in migraine frequency. MATERIAL AND METHODS: Patients with CS and PFO were included; 20 with planned closure of PFO and seven controls on medical treatment only. Endothelial function was assessed by peripheral arterial tonometry (EndoPatR ) and biomarkers of endothelial activation. Patients were followed longitudinally at baseline, day 1, 1 month, and 6 months. A headache diary was used to assess migraine frequency. RESULT: Mean age of the cohort was 45.4 years, and migraine prevalence was 50% whereof 84.6% had MA. Median EndoPatR index (RHI) at baseline was 1.60 (IQR 1.41-2.00). There was no change in RHI over time, either in closure patients (P = 0.66), nor in controls (P = 0.31), and there was no change in biomarkers of endothelial activation. Three migraine patients experienced worsening of migraine frequency directly after closure. DISCUSSION: Endothelial function did not change after closure of PFO. Although patients were lacking cardiovascular risk factors, a high proportion had impaired endothelial function. Whether ED can have predictive value, identifying PFO at higher risk for recurrent stroke warrants further investigations.

High cholesterol levels are associated with improved long-term survival after acute ischemic stroke.

BACKGROUND: Prior statin treatment and high admission cholesterol have been associated with favorable outcome after ischemic stroke (IS), a paradox not completely explained. The aim of this study was to investigate the effect of admission cholesterol levels and the impact of statin treatment on short- and long-term survival after IS. METHODS: Consecutive patients admitted in 2006 and 2010 were included in the study. Total cholesterol of 4.6 mmol/L or more was defined as high. Logistic regression analysis was performed to assess predictors of 1-month mortality, and Cox proportional hazard regression analysis was applied to investigate predictors of long-term mortality. RESULTS: Of 190 patients included in the final analysis, 21 (11%) died within 1 month and 61 (32%) died during 7 years of observation. Low cholesterol was associated with older age, lower blood pressure (BP), presence of angina, and higher risk of death. Three-month, 1-year, and 5-year survival rates were 100%, 98%, and 84%, respectively, in high cholesterol patients, compared with 92%, 87%, and 57% in low cholesterol group (P = .0001 with the log-rank test). Mortality risk was increased for patients with low cholesterol (hazard ratio: 1.97; 95% confidence interval [CI]: 1.05-3.69), after adjustment for age and admission National Institutes of Health Stroke Scale score. After further adjustment for angina and admission BP, the effect of cholesterol on mortality risk was still obvious, yet attenuated (hazard ratio: 1.87; 95% CI: .94-3.32). CONCLUSIONS: High admission cholesterol may be associated with increased long-term survival after IS. Future studies on the temporal profile of cholesterol levels and stroke outcome would be of interest.

Variants conferring risk of atrial fibrillation on chromosome 4q25.

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in humans and is characterized by chaotic electrical activity of the atria. It affects one in ten individuals over the age of 80 years, causes significant morbidity and is an independent predictor of mortality. Recent studies have provided evidence of a genetic contribution to AF. Mutations in potassium-channel genes have been associated with familial AF but account for only a small fraction of all cases of AF. We have performed a genome-wide association scan, followed by replication studies in three populations of European descent and a Chinese population from Hong Kong and find a strong association between two sequence variants on chromosome 4q25 and AF. Here we show that about 35% of individuals of European descent have at least one of the variants and that the risk of AF increases by 1.72 and 1.39 per copy. The association with the stronger variant is replicated in the Chinese population, where it is carried by 75% of individuals and the risk of AF is increased by 1.42 per copy. A stronger association was observed in individuals with typical atrial flutter. Both variants are adjacent to PITX2, which is known to have a critical function in left-right asymmetry of the heart.

Ischemic stroke and patent foramen ovale: risk factors and genetic profile.

BACKGROUND: Patent foramen ovale (PFO) is considered to be a risk factor for ischemic cerebrovascular disease (ICVD), especially in young people. However, the potential pathophysiological relevance in ischemic stroke is controversial and in need of further investigation. In this study, we examined the conventional risk factors and the distribution of 100 polymorphisms in 47 suspected susceptibility genes for ICVD in stroke patients with or without a PFO. METHODS: In the South Stockholm Ischemic Stroke Study, 928 ICVD patients and 602 controls were genotyped for 100 different gene polymorphisms. The stroke patients also underwent relevant investigation and standardized blood tests. Patients who underwent transeosophageal echocardiography as part of their investigation were divided into groups that either had or did not have a PFO. RESULTS: There were no significant differences in the 2 groups with regard to conventional risk factors or blood analyses. Three different polymorphisms located in the prothrombin, F2 (20210G/A), and apolipoprotein-C3 (-641A/C and -455T/A) genes were significantly associated with ICVD and PFO. The strongest association was found for F2 (P = .0049; odds ratio 26.4). CONCLUSIONS: We found that F2, which previously has been described as being a possible link between PFO and ICVD, was significantly associated with ICVD and PFO. There was also a trend toward an association between 2 other polymorphisms in the APO-CIII gene and PFO and ICVD.

Risk variants for atrial fibrillation on chromosome 4q25 associate with ischemic stroke.

OBJECTIVE: To find sequence variants that associate with the risk for ischemic stroke (IS), we performed a genome-wide association study. METHODS: We genotyped 1,661 Icelandic IS patients and 10,815 control subjects using the Infinium HumanHap300 chip (Illumina, San Diego, CA). A total of 310,881 single nucleotide polymorphisms (SNPs) were tested for association with IS, and the most significant signals were replicated in two large European IS sample sets (2,224 cases/2,583 control subjects). Two SNPs, rs2200733 and rs10033464, were tested further in additional European IS samples (2,327 patients and 16,760 control subjects). RESULTS: In the Icelandic samples and the two replication sets combined, rs2200733 associated significantly with cardioembolic stroke (CES) (odds ratio [OR], 1.54; p = 8.05 x 10(-9)). No other variants associated with IS or any of its subtypes. rs2200733 associated significantly with IS in all sample sets combined (OR, 1.26; p = 2.18 x 10(-10)), and both rs2200733 and its neighbour, rs10033464 associated strongly with CES (rs2200733: OR, 1.52; p = 5.8 x 10(-12); rs10033464: OR, 1.27; p = 6.1 x 10(-4)). Interestingly, rs2200733 also showed significant association to IS not classified as CES. INTERPRETATION: We discovered that variants previously shown to associate with atrial fibrillation (AF), rs2200733 and rs10033464, significantly associated with IS, with the strongest risk for CES. The association with noncardiogenic stroke is intriguing and suggests that atrial fibrillation may be underdiagnosed in patients presenting with stroke. This discovery may have implications for workup and treatment of IS.

Consensus statements and recommendations from the ESO-Karolinska Stroke Update Conference, Stockholm 11-13 November 2018.

The purpose of the European Stroke Organisation-Karolinska Stroke Update Conference is to provide updates on recent stroke therapy research and to give an opportunity for the participants to discuss how these results may be implemented into clinical routine. The meeting started 22 years ago as Karolinska Stroke Update, but since 2014 it is a joint conference with European Stroke Organisation. Importantly, it provides a platform for discussion on the European Stroke Organisation guidelines process and on recommendations to the European Stroke Organisation guidelines committee on specific topics. By this, it adds a direct influence from stroke professionals otherwise not involved in committees and work groups on the guideline procedure. The discussions at the conference may also inspire new guidelines when motivated. The topics raised at the meeting are selected by the scientific programme committee mainly based on recent important scientific publications. This year's European Stroke Organisation-Karolinska Stroke Update Meeting was held in Stockholm on 11-13 November 2018. There were 11 scientific sessions discussed in the meeting including two short sessions. Each session except the short sessions produced a consensus statement (Full version with background, issues, conclusions and references are published as web-material and at www.eso-karolinska.org and http://eso-stroke.org) and recommendations which were prepared by a writing committee consisting of session chair(s), scientific secretary and speakers. These statements were presented to the 250 participants of the meeting. In the open meeting, general participants commented on the consensus statement and recommendations and the final document were adjusted based on the discussion from the general participants Recommendations (grade of evidence) were graded according to the 1998 Karolinska Stroke Update meeting with regard to the strength of evidence. Grade A Evidence: Strong support from randomised controlled trials and statistical reviews (at least one randomised controlled trial plus one statistical review). Grade B Evidence: Support from randomised controlled trials and statistical reviews (one randomised controlled trial or one statistical review). Grade C Evidence: No reasonable support from randomised controlled trials, recommendations based on small randomised and/or non-randomised controlled trials evidence.

PDE4D and ALOX5AP genetic variants and risk for Ischemic Cerebrovascular Disease in Sweden.

BACKGROUND: Genetic variants in Phosphodiesterase 4D (PDE4D) and 5-lipoxygenase activating protein (ALOX5AP) have been shown to confer risk of Ischemic Cerebrovascular Disease (ICVD) in Iceland. We investigated whether these variants associate with ICVD in Sweden. METHODS: Previously published PDE4D and ALOX5AP gene variants were genotyped for cases (685) and controls (751). In PDE4D this consisted of SNP41, SNP45 and microsatellite AC008818-1 and in ALOX5AP four SNPs that define the HapA haplotype. RESULTS: The PDE4D SNPs, showed a non-significant risk in the ICVD group which increased for the Large Artery Atherosclerosis subtype (SNP45: RR=1.43, P=0.063, SNP41: RR=1.57, P=0.018). The SNP haplotype GA (SNP45, SNP41) showed an increased risk for LAA (RR=1.58, P=0.016) and the combined LAA and Cardioembolism (CE) (RR=1.34, P=0.031) subgroups. As the SNPs are in strong LD, this haplotype corresponds to the complement of the protective haplotype in the Icelandic study. No allele of the microsatellite marker, showed association to stroke or any subtype and nor did the Icelandic PDE4D at-risk haplotype (GA0). We did not confirm the association between ALOX5AP HapA haplotype and ICVD, but a non-significant risk was observed in the LAA subtype. CONCLUSION: Our PDE4D findings although non-significant considering the number of markers and phenotypes tested, are consistent with the association observed in the original study, with a trend observed in the whole ICVD group, which was strengthened in the stroke subtype LAA and the combined group of LAA and CE stroke. This supports the notion that PDE4D contributes to the risk of developing stroke.

Elevated plasma homocysteine upon ischemic stroke is associated with increased long-term mortality in women.

BACKGROUND: Ischemic stroke is a leading cause of death worldwide, despite preventive and therapeutic advances during the last twenty years. Blood-borne biomarkers have been studied in association to short- and long-term outcome, in order to investigate possible modifiable predictors of disability and death. Increased homocysteine has been associated with increased vascular risk and unfavorable outcome, but homocysteine lowering treatment has not consistently been successful in risk reduction. The aim of this study was to investigate homocysteine levels upon acute ischemic stroke in association to long-term mortality. METHODS: Of 622 patients included in our hospital-based registry, 331 survived the first month after admission, and had a diagnosis of ischemic stroke and available homocysteine values. All-cause and vascular mortality were investigated based on the national patient- and cause of death-registries. Survival analysis and Cox proportional hazard models were used to investigate time to death and predictors of outcome. RESULTS: Of 331 patients, 148 (45%) had low homocysteine (<13 micromol/L) and 183 (55%) had high homocysteine (> = 13 micromol/L). During 10 years of follow-up (median 5.5 years), 47 patients (32%) with low homocysteine and 94 (51%) with high homocysteine died (p<0.0001). Estimated median survival was not reached for the low homocysteine group, and was 80 months in the high homocysteine group (p with log-rank test 0.002). High homocysteine was not independently associated with increased risk for death after adjustment for age, sex, comorbidities, and eGFR (HR 1.29, 95% CI 0.86-1.93; p = 0.2). Subgroup analysis by sex showed that high homocysteine was an independent predictor of mortality in women after adjustment for age and vascular comorbidities (HR 1.85; 95% CI 1.03-3.31; p = 0.04), but not in men (HR 0.87; 95% CI 0.52-1.43; p = 0.6). CONCLUSION: Increased plasma homocysteine (> = 13 micromol/L) upon acute ischemic stroke was not independently associated with mortality in our study. In the subgroup of women, high homocysteine was associated with increased five-year risk of death. Our study's retrospective design and the exploratory nature of subgroup analysis, prevent robust conclusions based on that observation. Future studies on homocysteine levels before as well as upon stroke will shed further light on a possible causal association.

Hospital comparison of stroke care in Sweden: a register-based study.

BACKGROUND AND PURPOSE: The objective of this study was to estimate the level of health outcomes and resource use at a hospital level during the first year after a stroke, and to identify any potential differences between hospitals after adjusting for patient characteristics (case mix). METHOD: Data from several registries were linked on individual level: seven regional patient administrative systems, Swedish Stroke Register, Statistics Sweden, National Board of Health and Welfare and Swedish Social Insurance Agency. The study population consisted of 14 125 patients presenting with a stroke during 2010. Case-mix adjusted analysis of hospital differences was made on five aspects of health outcomes and resource use, 1 year post-stroke. RESULTS: The results indicated that 26% of patients had died within a year of their stroke. Among those who survived, almost 5% had a recurrent stroke and 40% were left with a disability. On average, the patients had 22 inpatient days and 23 outpatient visits, and 13% had moved into special housing. There were significant variations between hospitals in levels of health outcomes achieved and resources used after adjusting for case mix. CONCLUSION: Differences in health outcomes and resource use between hospitals were substantial and not entirely explained by differences in patient mix, indicating tendencies of unequal stroke care in Sweden. Healthcare organisation of regions and other structural features could potentially explain parts of the differences identified.

Electrical Bioimpedance Spectroscopy on Acute Unilateral Stroke Patients: Initial Observations regarding Differences between Sides.

PURPOSE: Electrical Bioimpedance Cerebral Monitoring is assessment in real time of health of brain tissue through study of passive dielectric properties of brain. During the last two decades theory and technology have been developed in parallel with animal experiments aiming to confirm feasibility of using bioimpedance-based technology for prompt detection of brain damage. Here, for the first time, we show that electrical bioimpedance measurements for left and right hemispheres are significantly different in acute cases of unilateral stroke within 24 hours from onset. METHODS: Electrical BIS measurements have been taken in healthy volunteers and patients suffering from acute stroke within 24 hours of onset. BIS measurements have been obtained using SFB7 bioimpedance spectrometer manufactured by Impedimed ltd. and 4-electrode method. Measurement electrodes, current, and voltage have been placed according to 10-20 EEG system obtaining mutual BIS measurements from 4 different channels situated in pairs symmetrically from the midsagittal line. Obtained BIS data has been analyzed, assessing for symmetries and differences regarding healthy control data. RESULTS: 7 out of 10 patients for Side-2-Side comparisons and 8 out 10 for central/lateral comparison presented values outside the range defined by healthy control group. When combined only 1 of 10 patients exhibited values within the healthy range. CONCLUSIONS: If these initial observations are confirmed with more patients, we can foresee emerging of noninvasive monitoring technology for brain damage with the potential to lead to paradigm shift in treatment of brain stroke and traumatic brain damage.

Idiopathic small fiber neuropathy: phenotype, etiologies, and the search for fabry disease.

BACKGROUND AND PURPOSE: The etiology of small fiber neuropathy (SFN) often remains unclear. Since SFN may be the only symptom of late-onset Fabry disease, it may be underdiagnosed in patients with idiopathic polyneuropathy. We aimed to uncover the etiological causes of seemingly idiopathic SFN by applying a focused investigatory procedure, to describe the clinical phenotype of true idiopathic SFN, and to elucidate the possible prevalence of late-onset Fabry disease in these patients. METHODS: Forty-seven adults younger than 60 years with seemingly idiopathic pure or predominantly small fiber sensory neuropathy underwent a standardized focused etiological and clinical investigation. The patients deemed to have true idiopathic SFN underwent genetic analysis of the alpha-galactosidase A gene (GLA) that encodes the enzyme alpha-galactosidase A (Fabry disease). RESULTS: The following etiologies were identified in 12 patients: impaired glucose tolerance (58.3%), diabetes mellitus (16.6%), alcohol abuse (8.3%), mitochondrial disease (8.3%), and hereditary neuropathy (8.3%). Genetic alterations of unknown clinical significance in GLA were detected in 6 of the 29 patients with true idiopathic SFN, but this rate did not differ significantly from that in healthy controls (n=203). None of the patients with genetic alterations in GLA had significant biochemical abnormalities simultaneously in blood, urine, and skin tissue. CONCLUSIONS: A focused investigation may aid in uncovering further etiological factors in patients with seemingly idiopathic SFN, such as impaired glucose tolerance. However, idiopathic SFN in young to middle-aged Swedish patients does not seem to be due to late-onset Fabry disease.

Visualising neuroinflammation in post-stroke patients: a comparative PET study with the TSPO molecular imaging biomarkers [11C]PK11195 and [11C]vinpocetine.

With the main objective of comparing the prospective diagnostic power of two 11C-labelled molecular imaging biomarkers with affinity for TSPO and used for the visualisation of activated microglia after a stroke, we measured with positron emission tomography (PET) in four post-stroke patients the regional brain uptake and binding potential of [11C]vinpocetine and [11C]PK11195. Percentage standard uptake values (%SUV) and binding potential (BPND) were used as outcome measures. The total peak brain uptake value and average global brain uptake value were higher for [11C]vinpocetine than for [11C]PK11195. The regional %SUV values were significantly higher for [11C]vinpocetine than for [11C]PK11195 in the hemispheres as well as in almost all standard brain regions. The %SUV values of [11C]vinpocetine were higher in the peri-infarct zone than in the ischaemic core, however, the difference did not prove to be significant. There was basically no difference in %SUV values between the ischaemic core and the peri-infarct zone for [11C]PK11195. The BPND values for [11C]vinpocetine were higher in all standard regions than those for [11C]PK11195, but the difference was not significant between them. The BPND values of [11C]vinpocetine were higher in the peri-infarct zone than in the ischaemic core, however, the difference did not prove to be significant. A comparative analysis of the two ligands indicates that [11C]vinpocetine shows a number of favourable characteristics over [11C]PK11195, but to demonstrate that it may serve as a prospective molecular imaging biomarker of microglia activation in post-stroke patients, further studies are required.

Evolution of microglial activation in ischaemic core and peri-infarct regions after stroke: a PET study with the TSPO molecular imaging biomarker [((11))C]vinpocetine.

Although there is increasing evidence for microglial activation after an ischaemic stroke in the infarct core and the peri-infarct region, the "evolution" of the process in stroke patients is poorly known. Using PET and [((11))C]vinpocetine, we measured the regional changes of TSPO in the brain of nine ischaemic stroke patients up to 14weeks after the insult. Already a week after stroke there was an increased radioligand uptake, indicating the up-regulation of TSPO and the presence of activated microglia, in both the ischaemic core and the peri-infarct zone. This increased activation showed a steady decrease with post stroke time. The proportion between %SUV values in the peri-infarct zone and the ischaemic core increased with time. There were no time-dependent TSPO activity changes in other regions, not affected directly by the stroke. The present observations demonstrate that increased regional microglia activation, as a consequence of stroke, can be visualised with PET, using the TSPO molecular imaging biomarker [((11))C]vinpocetine. The evolution of this microglial activation shows a time dependent decrease the gradient of which is different between the peri-infarct zone and the ischaemic core. The findings indicate an increased microglial activation in the peri-stroke region for several weeks after the insult.

A sequence variant in ZFHX3 on 16q22 associates with atrial fibrillation and ischemic stroke.

We expanded our genome-wide association study on atrial fibrillation (AF) in Iceland, which previously identified risk variants on 4q25, and tested the most significant associations in samples from Iceland, Norway and the United States. A variant in the ZFHX3 gene on chromosome 16q22, rs7193343-T, associated significantly with AF (odds ratio OR = 1.21, P = 1.4 x 10(-10)). This variant also associated with ischemic stroke (OR = 1.11, P = 0.00054) and cardioembolic stroke (OR = 1.22, P = 0.00021) in a combined analysis of five stroke samples.

ASIP and TYR pigmentation variants associate with cutaneous melanoma and basal cell carcinoma.

Fair color increases risk of cutaneous melanoma (CM) and basal cell carcinoma (BCC). Recent genome-wide association studies have identified variants affecting hair, eye and skin pigmentation in Europeans. Here, we assess the effect of these variants on risk of CM and BCC in European populations comprising 2,121 individuals with CM, 2,163 individuals with BCC and over 40,000 controls. A haplotype near ASIP, known to affect a similar spectrum of pigmentation traits as MC1R variants, conferred significant risk of CM (odds ratio (OR) = 1.45, P = 1.2 x 10(-9)) and BCC (OR = 1.33, P = 1.2 x 10(-6)). The variant in TYR encoding the R402Q amino acid substitution, previously shown to affect eye color and tanning response, conferred risk of CM (OR = 1.21, P = 2.8 x 10(-7)) and BCC (OR = 1.14, P = 6.1 x 10(-4)). An eye color variant in TYRP1 was associated with risk of CM (OR = 1.15, P = 4.6 x 10(-4)). The association of all three variants is robust with respect to adjustment for the effect of pigmentation.

The same sequence variant on 9p21 associates with myocardial infarction, abdominal aortic aneurysm and intracranial aneurysm.

Recently, two common sequence variants on 9p21, tagged by rs10757278-G and rs10811661-T, were reported to be associated with coronary artery disease (CAD) and type 2 diabetes (T2D), respectively. We proceeded to further investigate the contributions of these variants to arterial diseases and T2D. Here we report that rs10757278-G is associated with, in addition to CAD, abdominal aortic aneurysm (AAA; odds ratio (OR) = 1.31, P = 1.2 x 10(-12)) and intracranial aneurysm (OR = 1.29, P = 2.5 x 10(-6)), but not with T2D. This variant is the first to be described that affects the risk of AAA and intracranial aneurysm in many populations. The association of rs10811661-T to T2D replicates in our samples, but the variant does not associate with any of the five arterial diseases examined. These findings extend our insight into the role of the sequence variant tagged by rs10757278-G and show that it is not confined to atherosclerotic diseases.