Hypercoagulability Is a Stronger Risk Factor for Ischaemic Stroke than for Myocardial Infarction: A Systematic Review

Activated partial thromboplastin time-based clot waveform analysis: a potential for application in acute myocardial infarction and its complications

Activated partial thromboplastin time (aPTT)-based clot waveform analysis (CWA) is a plasma-based global haemostatic assay. Elevated CWA parameters have been associated with hypercoagulability in venous thromboembolism, but its role in arterial thrombotic disease is uncertain. This study aims to explore the relationship between aPTT-based CWA and acute myocardial infarction (AMI) and its complications. In a retrospective cohort study of patients with AMI who underwent emergency cardiac catheterisation, pre-procedural aPTT and CWA parameters-min1, min2 and max2 were measured. These were compared against a control group of patients, consisting of patients who underwent elective orthopaedic and urological procedures. Within the AMI cohort, we also compared aPTT and CWA parameters of those with and without clinical complications of AMI. Results: Compared to controls (N = 109), patients with AMI (N = 214) had shorter aPTT (26.7 ± 3.3 s vs 27.9 ± 1.7 s, P < 0.001) and higher CWA parameters (min1: 6.11 ± 1.40%/s vs 5.58 ± 1.14%/s; min2: 0.98 ± 0.23%/s2 vs 0.90 ± 0.19%/s2; max2: 0.81 ± 0.20%/s2 vs 0.74 ± 0.16%/s2, all P ≤ 0.001). There was an increased incidence of elevated CWA parameters, in the AMI group, with odds ratio (OR) of 2.06 [95% CI 1.10-3.86], 2.23 (95% CI 1.18-4.24) and 2.01 (95% CI 1.07-3.77) for min1, min2 and max2, respectively. Similarly, elevated min1 and min2 were both individually associated with the presence of adverse outcomes of AMI, both with ORs of 2.63 (95% CI 1.24-5.59). Elevated aPTT-based CWA parameters are significantly associated with the occurrence of AMI and its complications. These findings identify the potential utility of CWA as risk and prognostic markers for AMI and warrants future works.

Characterisation of young stroke presentations, pathways of care, and support for 'invisible' difficulties: a retrospective clinical audit study

Background Young stroke survivors are likely to be discharged home from acute hospital care without rehabilitation more quickly than older survivors, but it is not clear why. File-audit studies capturing real-world clinical practice are lacking for this cohort. We aimed to compare characteristics and care pathways of young and older survivors and describe stroke presentations and predictors of pathways of care in young survivors (≤45years), including a focus on care received for 'invisible' (cognitive, psychological) difficulties. Methods A retrospective audit of 847 medical records (67 young stroke survivors, mean age=36years; 780 older patients, mean age=70years) was completed for stroke survivors admitted to an Australian tertiary hospital. Stroke characteristics and presence of cognitive difficulties (identified through clinician opinion or cognitive screening) were used to predict length of stay and discharge destination in young stroke survivors. Results There were no differences in length of stay between young and older survivors, however, young stroke survivors were more likely to be discharged home without rehabilitation (though this may be due to milder strokes observed in young stroke survivors). For young stroke survivors, stroke severity and age predicted discharge destination, while cognitive difficulties predicted longer length of stay. While almost all young survivors were offered occupational therapy and physiotherapy, none received psychological input (clinical, health or neuropsychology). Conclusions Cognitive and psychological needs of young stroke survivors may remain largely unmet by a service model designed for older people. Findings can inform service development or models of care, such as the new Australian Young Stroke Service designed to better meet the needs of young survivors.

Current and potentially novel antithrombotic treatment in acute ischemic stroke

Acute ischemic stroke (AIS) is the most common type of stroke and requires immediate reperfusion. Current acute reperfusion therapies comprise the administration of intravenous thrombolysis and/or endovascular thrombectomy. Although these acute reperfusion therapies are increasingly successful, optimized secondary antithrombotic treatment remains warranted, specifically to reduce the risk of major bleeding complications. In the development of AIS, coagulation and platelet activation play crucial roles by driving occlusive clot formation. Recent studies implicated that the intrinsic route of coagulation plays a more prominent role in this development, however, this is not fully understood yet. Next to the acute treatments, antithrombotic therapy, consisting of anticoagulants and/or antiplatelet therapy, is successfully used for primary and secondary prevention of AIS but at the cost of increased bleeding complications. Therefore, better understanding the interplay between the different pathways involved in the pathophysiology of AIS might provide new insights that could lead to novel treatment strategies. This narrative review focuses on the processes of platelet activation and coagulation in AIS, and the most common antithrombotic agents in primary and secondary prevention of AIS. Furthermore, we provide an overview of promising novel antithrombotic agents that could be used to improve in both acute treatment and stroke prevention.

Acute effects of high intensity interval training versus moderate intensity continuous training on haemostasis in patients with coronary artery disease

Exercise training is associated with an acute net increase in coagulation, which may increase the risk of atherothrombosis in coronary artery disease (CAD) patients. We sought to compare the acute haemostatic effects of a bout of moderate-intensity continuous (MICT) and high-intensity interval training (HIIT) in patients with CAD. Patients after a recent myocardial infarction were randomized into a HIIT or MICT session of exercise training on a stationary bike. Blood was sampled at baseline, after the exercise bout and after a one-hour resting period. We measured overall haemostatic potential (OHP), overall coagulation potential (OCP), fibrinogen, D-dimer and von Willebrand factor (vWF) and calculated overall fibrinolytic potential (OFP). Linear mixed models for repeated measures were constructed to assess the treatment effect. A total of 117 patients were included. OCP, OHP, fibrinogen, D-dimer and vWF significantly increased after exercise and returned to baseline after a one-hour rest, OFP decreased after exercise and returned to baseline levels after a one-hour rest. Linear mixed models showed a significant difference between HIIT and MICT in fibrinogen (p 0.043) and D-dimer (p 0.042). Our study has shown that an exercise bout is associated with a transient procoagulant state in patients with CAD, with similar exercise-induced haemostatic changes for HIIT and MICT.

Degree of COVID-19 severity and mortality in stroke: correlation of clinical and laboratory parameters

BACKGROUND

Stroke is one of the neurological manifestations of COVID-19, leading to a significant risk of morbidity and mortality. Clinical manifestations and laboratory parameters were investigated to determine mortality predictors in this case.

METHOD

The case control study was conducted at Dr. Sardjito General Hospital,Yogyakarta, Indonesia, with data collected between July 2020 and August 2021. All recorded clinical and laboratory data from acute stroke patients with confirmed COVID-19 were collected. Baseline characteristics, bivariate, and multivariate analyses were assessed to determine significant predictors for mortality.

RESULT

This study involved 72 subjects with COVID-19 and stroke. The majority experienced ischemic stroke, with hypertension as the most prevalent comorbidity. Notably, 45.8% of subjects (p < 0.05) loss of consciousness and 72.2% of exhibited motor deficits (p < 0.05). Severe degree of COVID-19 was observed in 52.8% of patients, with respiratory distress and death rates of 56.9% and 58.3%. Comparison of surviving and deceased groups highlighted significant differences in various clinical and laboratory characteristics differences. Hazard ratio (HR) analysis identified loss of consciousness (HR = 2.68; p = 0.01), motor deficit (HR = 2.34; p = 0.03), respiratory distress (HR = 81.51; p < 0.001), and monocyte count (HR:1.002; p = 0.04) as significant predictors of mortality.

CONCLUSION

Mortality in COVID-19 patients with stroke was significantly associated with loss of consciousness, motor deficit, respiratory distress, and raised monocyte count. The risk of mortality is heightened when multiple factors coexist.

Neurological manifestations of SARS-CoV-2: complexity, mechanism and associated disorders

BACKGROUND

Coronaviruses such as Severe Acute Respiratory Syndrome coronavirus (SARS), Middle Eastern Respiratory Syndrome (MERS) and Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) are associated with critical illnesses, including severe respiratory disorders. SARS-CoV-2 is the causative agent of the deadly COVID-19 illness, which has spread globally as a pandemic. SARS-CoV-2 may enter the human body through olfactory lobes and interact with the angiotensin-converting enzyme2 (ACE2) receptor, further facilitating cell binding and entry into the cells. Reports have shown that the virus can pass through the blood-brain barrier (BBB) and enter the central nervous system (CNS), resulting in various disorders. Cell entry by SARS-CoV-2 largely relies on TMPRSS2 and cathepsin L, which activate S protein. TMPRSS2 is found on the cell surface of respiratory, gastrointestinal and urogenital epithelium, while cathepsin-L is a part of endosomes.

AIM

The current review aims to provide information on how SARS-CoV-2 infection affects brain function.. Furthermore, CNS disorders associated with SARS-CoV-2 infection, including ischemic stroke, cerebral venous thrombosis, Guillain-Barré syndrome, multiple sclerosis, meningitis, and encephalitis, are discussed. The many probable mechanisms and paths involved in developing cerebrovascular problems in COVID patients are thoroughly detailed.

MAIN BODY

There have been reports that the SARS-CoV-2 virus can cross the blood-brain barrier (BBB) and enter the central nervous system (CNS), where it could cause a various illnesses. Patients suffering from COVID-19 experience a range of neurological complications, including sleep disorders, viral encephalitis, headaches, dysgeusia, and cognitive impairment. The presence of SARS-CoV-2 in the cerebrospinal fluid (CSF) of COVID-19 patients has been reported. Health experts also reported its presence in cortical neurons and human brain organoids. The possible mechanism of virus infiltration into the brain can be neurotropic, direct infiltration and cytokine storm-based pathways. The olfactory lobes could also be the primary pathway for the entrance of SARS-CoV-2 into the brain.

CONCLUSIONS

SARS-CoV-2 can lead to neurological complications, such as cerebrovascular manifestations, motor movement complications, and cognitive decline. COVID-19 infection can result in cerebrovascular symptoms and diseases, such as strokes and thrombosis. The virus can affect the neural system, disrupt cognitive function and cause neurological disorders. To combat the epidemic, it is crucial to repurpose drugs currently in use quickly and develop novel therapeutics.

Intake of dietary flavonoids and incidence of ischemic heart disease in the Danish Diet, Cancer, and Health cohort

BACKGROUND/OBJECTIVES

Few studies have investigated the association between dietary flavonoid intake, including all major subclasses, and the long-term risk of ischemic heart disease (IHD). We examined whether dietary flavonoid intake associated with IHD incidence, assessing the possible modifying role of sex and smoking, in participants from the Danish Diet, Cancer, and Health study.

SUBJECTS/METHODS

In a cohort study design, 54,496 adults (46.8% male), aged 50-64 years, without a history of IHD, were followed for up to 23 years. Habitual dietary flavonoid intake was estimated from food frequency questionnaires using Phenol-Explorer. Incident cases of IHD were identified within Danish nationwide health registries. Restricted cubic splines in Cox proportional hazards models were used to examine associations between flavonoid intake and IHD risk.

RESULTS

During follow-up, 5560 IHD events were recorded. No overall association was seen between total flavonoid intake, nor any subclass, and IHD, following adjustment for demographics, lifestyle, and dietary confounders. Stratified by sex and smoking status, higher intakes of specific subclasses associated with lower IHD risk among ever-smokers [Q5 vs. Q1 flavonols HR (95% CI): 0.90 (0.82, 0.99); flavanol oligo+polymers: 0.88 (0.80, 0.97)], but not among never-smokers, nor either sex specifically.

CONCLUSIONS

While we did not find clear evidence that higher habitual dietary flavonoid intake was associated with lower IHD risk, these results do not exclude the possibility that certain subclasses may have a protective role in prevention of IHD among population sub-groups; this was evident among smokers, who are at a higher risk of atherosclerosis.

Strategies for Therapeutic Amelioration of Aberrant Plasma Zn2+ Handling in Thrombotic Disease: Targeting Fatty Acid/Serum Albumin-Mediated Effects

The initiation, maintenance and regulation of blood coagulation is inexorably linked to the actions of Zn²⁺ in blood plasma. Zn²⁺ interacts with a variety of haemostatic proteins in the bloodstream including fibrinogen, histidine-rich glycoprotein (HRG) and high molecular weight kininogen (HMWK) to regulate haemostasis. The availability of Zn²⁺ to bind such proteins is controlled by human serum albumin (HSA), which binds 70–85% of plasma Zn²⁺ under basal conditions. HSA also binds and transports non-esterified fatty acids (NEFAs). Upon NEFA binding, there is a change in the structure of HSA which leads to a reduction in its affinity for Zn²⁺. This enables other plasma proteins to better compete for binding of Zn²⁺. In diseases where elevated plasma NEFA concentrations are a feature, such as obesity and diabetes, there is a concurrent increase in hypercoagulability. Evidence indicates that NEFA-induced perturbation of Zn²⁺-binding by HSA may contribute to the thrombotic complications frequently observed in these pathophysiological conditions. This review highlights potential interventions, both pharmaceutical and non-pharmaceutical that may be employed to combat this dysregulation. Lifestyle and dietary changes have been shown to reduce plasma NEFA concentrations. Furthermore, drugs that influence NEFA levels such as statins and fibrates may be useful in this context. In severely obese patients, more invasive therapies such as bariatric surgery may be useful. Finally, other potential treatments such as chelation therapies, use of cholesteryl transfer protein (CETP) inhibitors, lipase inhibitors, fatty acid inhibitors and other treatments are highlighted, which with additional research and appropriate clinical trials, could prove useful in the treatment and management of thrombotic disease through amelioration of plasma Zn²⁺ dysregulation in high-risk individuals.

Risk of ischaemic heart diseases and stroke in behçet disease: A systematic review and meta-analysis

BACKGROUND

Behçet disease (BD) is a systemic vasculitis. In addition to the mucocutaneous lesions, the vascular injury of pathophysiology in BD is theoretically correlated with cardiovascular diseases. This study aimed to elucidate the association of BD with ischaemic heart diseases (IHDs) and stroke.

METHODS

A systematic search of PubMed, Embase, Web of Science and Cochrane Library databases was performed for all relevant observational studies from database inception until 10 July 2021. No language restriction was applied. A random-effects model was used for meta-analysis.

RESULTS

A total of six observational studies consisting of three cohort studies, two cross-sectional studies and one study with both study designs were adopted in the meta-analysis. The numbers of patients with BD and healthy controls were 9,813 and 41,802, respectively. The pooled analysis demonstrated no significant association between BD and IHD. By contrast, we found that patients with BD had a significantly higher risk of stroke (adjusted hazard ratio, 2.083; 95% confidence interval, 1.339-3.240; p = 0.001) than healthy controls. We observed substantial heterogeneity across studies in few meta-analyses, but no significant publication bias was detected in any of the meta-analyses.

CONCLUSIONS

BD was significantly associated with stroke but not IHD. Physicians should be aware of possible vascular and neurological complications during care of patients with BD.

Protein C or Protein S deficiency associates with paradoxically impaired platelet-dependent thrombus and fibrin formation under flow

Background

Low plasma levels of protein C or protein S are associated with venous thromboembolism rather than myocardial infarction. The high coagulant activity in patients with thrombophilia with a (familial) defect in protein C or S is explained by defective protein C activation, involving thrombomodulin and protein S. This causes increased plasmatic thrombin generation.

Objective

Assess the role of platelets in the thrombus- and fibrin-forming potential in patients with familial protein C or protein S deficiency under high-shear flow conditions.

Patients/Methods

Whole blood from 23 patients and 15 control subjects was perfused over six glycoprotein VI-dependent microspot surfaces. By real-time multicolor microscopic imaging, kinetics of platelet thrombus and fibrin formation were characterized in 49 parameters.

Results and Conclusion

Whole-blood flow perfusion over collagen, collagen-like peptide, and fibrin surfaces with low or high GPVI dependency indicated an unexpected impairment of platelet activation, thrombus phenotype, and fibrin formation but unchanged platelet adhesion, observed in patients with protein C deficiency and to a lesser extent protein S deficiency, when compared to controls. The defect extended from diminished phosphatidylserine exposure and thrombus contraction to delayed and suppressed fibrin formation. The mechanism was thrombomodulin independent, and may involve negative platelet priming by plasma components.

Major adverse cardiovascular events in survivors of immune-mediated thrombotic thrombocytopenic purpura

Cardiovascular disease is a leading cause of death in survivors of immune-mediated thrombotic thrombocytopenic purpura (iTTP), but the epidemiology of major adverse cardiovascular events (MACE) in iTTP survivors is unknown. We evaluated the prevalence and risk factors for MACE, defined as the composite of non-fatal or fatal myocardial infarction (MI), stroke, and cardiac revascularization, during clinical remission in two large iTTP cohorts (Johns Hopkins University and Ohio State University). Of 181 patients followed for ≥ 3 months after recovery from acute iTTP, 28.6% had a MACE event over a median follow up of 7.6 years. Stroke was the most common type of MACE (18.2%), followed by non-fatal MI (6.6%), cardiac revascularization (4.9%) and fatal MI (0.6%). Compared to the general United States population, iTTP survivors were younger at first stroke in remission (males [56.5 years vs. 68.6 years, p = 0.031], females [49.7 years vs. 72.9 years, p <  0.001]) or MI in remission (males [56.5 years vs. 65.6 years, p <  0.001] and females [53.1 years vs. 72.0 years, p < 0.001]). Age (HR 1.03 [95% CI 1.002-1.054]), race (Black/Other vs. White) (HR 2.32 [95% CI 1.12-4.82]), and diabetes mellitus (HR 2.37 [95% CI 1.09-0.03]) were associated with MACE in a Cox regression model also adjusted for sex, hypertension, obesity, hyperlipidemia, chronic kidney disease, atrial fibrillation, autoimmune disease, and relapsing iTTP. Remission ADAMTS13 activity was not significantly associated with MACE. In conclusion, iTTP survivors experience high rates of MACE and may benefit from aggressively screening for and managing cardiovascular risk factors.

Acute Viral Illnesses and Ischemic Stroke: Pathophysiological Considerations in the Era of the COVID-19 Pandemic

The severe acute respiratory syndrome coronavirus 2 or coronavirus disease 2019 (COVID-19) pandemic has raised concerns about the correlation with this viral illness and increased risk of stroke. Although it is too early in the pandemic to know the strength of the association between COVID-19 and stroke, it is an opportune time to review the relationship between acute viral illnesses and stroke. Here, we summarize pathophysiological principles and available literature to guide understanding of how viruses may contribute to ischemic stroke. After a review of inflammatory mechanisms, we summarize relevant pathophysiological principles of vasculopathy, hypercoagulability, and hemodynamic instability. We will end by discussing mechanisms by which several well-known viruses may cause stroke in an effort to inform our understanding of the relationship between COVID-19 and stroke.

Systemic thrombosis in a large cohort of COVID-19 patients despite thromboprophylaxis: A retrospective study

BACKGROUND

Incidence of thrombotic events associated to Coronavirus disease-2019 (COVID-19) is difficult to assess and reported rates differ significantly. Optimal thromboprophylaxis is unclear.

OBJECTIVES

We aimed to analyze the characteristics of patients with a confirmed thrombotic complication including inflammatory and hemostatic parameters, compare patients affected by arterial vs venous events and examine differences between survivors and non-survivors. We reviewed compliance with thromboprophylaxis and explored how the implementation of a severity-adjusted protocol could have influenced outcome.

METHODS

Single-cohort retrospective study of COVID-19 patients admitted, from March 3 to May 3 2020, to the Infanta Leonor University Hospital in Madrid, epicenter of the Spanish outbreak.

RESULTS

Among 1127 patients, 80 thrombotic events were diagnosed in 69 patients (6.1% of the entire cohort). Forty-three patients (62%) suffered venous thromboembolism, 18 (26%) arterial episodes and 6 (9%) concurrent venous and arterial thrombosis. Most patients (90%) with a confirmed thrombotic complication where under low-molecular-weight heparin treatment. Overt disseminated intravascular coagulation (DIC) was rare. Initial ISTH DIC score and pre-event CRP were significantly higher among non-survivors. In multivariate analysis, arterial localization was an independent predictor of mortality (OR = 18, 95% CI: 2.4-142, p < .05).

CONCLUSIONS

Despite quasi-universal thromboprophylaxis, COVID-19 lead to a myriad of arterial and venous thrombotic events. Considering the subgroup of patients with thrombotic episodes, arterial events appeared earlier in the course of disease and conferred very poor prognosis, and an ISTH DIC score ≥ 3 at presentation was identified as a potential predictor of mortality. Severity-adjusted thromboprophylaxis seemed to decrease the number of events and could have influenced mortality. Randomized controlled trials are eagerly awaited.

Accelerated Spatial Fibrin Growth and Impaired Contraction of Blood Clots in Patients with Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an autoimmune disease associated with thrombotic complications. To elucidate pathogenic mechanisms, hemostatic disorders in RA were correlated with other laboratory and clinical manifestations. Hemostasis was assessed using relatively new complementary tests, the spatial growth of a plasma clot (Thrombodynamics assay), and contraction of whole blood clots. Platelet functionality was assessed with flow cytometry that quantified the expression of P-selectin and the fibrinogen-binding capacity of platelets before and after activation with a thrombin receptor-activating peptide. Parameters of fibrin clot growth and the kinetics of contraction of blood clots were significantly altered in patients with RA compared to the control group. In Thrombodynamics measurements, an increase in the clot growth rate, size, and optical density of plasma clots altogether indicated chronic hypercoagulability. The rate and extent of blood clot contraction in patients with RA was significantly reduced and associated with platelet dysfunction revealed by an impaired response to activation. Changes in the parameters of clot growth and contraction correlated with the laboratory signs of systemic inflammation, including hyperfibrinogenemia. These results confirm the pathogenic role of hemostatic disorders in RA and support the validity of fibrin clot growth and the blood clot contraction assay as indicators of a (pro)thrombotic state.

Detection of Citrullinated Fibrin in Plasma Clots of Rheumatoid Arthritis Patients and Its Relation to Altered Structural Clot Properties, Disease-Related Inflammation and Prothrombotic Tendency

Aims

The risk of cardiovascular events in patients with Rheumatoid Arthritis (RA) is disproportionately heightened as a result of systemic inflammation. The relative effect of autoimmune-associated citrullination on the structure and thrombotic potential of fibrin(ogen) remains unknown. We therefore compared indices of vascular function, inflammation, coagulation and fibrin clot composition in RA patients with healthy controls and evaluated parameter association with disease presence.

Methods

Blood samples were collected from 30 RA patients and 30 age- and gender-matched healthy volunteers. Levels of serum amyloid A (SAA), c-reactive protein (CRP), soluble intercellular adhesion molecule 1 (sICAM-1) and soluble vascular cell adhesion molecule 1 (sVCAM-1) was measured using a sandwich immunoassay. Whole blood coagulation was assessed using Thromboelastography (TEG^®). Fibrin clot networks and fiber structure was investigated using Scanning Electron Microscopy. The detection and quantification of citrullination in formed fibrin clots was performed using a fluorescently labeled Citrulline monoclonal antibody with Fluorescence Wide Field Microscopy.

Results

Concentrations of SAA, CRP and ICAM-1 were significantly elevated in RA patients compared to controls. TEG parameters relating to coagulation initiation, rate of fibrin cross-linking, and time to reach maximum thrombus generation were attenuated in RA patients. Microscopic analysis revealed denser networks of thicker fibrin fibers in RA patients compared to controls and multiple citrullinated regions within fibrin clot structures in RA patients were present.

Conclusion

Our findings provide novel evidence for the citrullination of fibrin within vasculature is more prominent in RA plasma compared to control plasma and plasma is more accessible than synovial fluid. Citrullinated fibrinogen could play a role as a determinant of thrombotic risk in RA patients.

Coagulation factor XII, XI, and VIII activity levels and secondary events after first ischemic stroke

BACKGROUND

Though risk for recurrent vascular events is high following ischemic stroke, little knowledge about risk factors for secondary events post-stroke exists.

OBJECTIVES

Coagulation factors XII, XI, and VIII (FXII, FXI, and FVIII) have been implicated in first thrombotic events, and our aim was to estimate their effects on vascular outcomes within 3 years after first stroke.

PATIENTS/METHODS

In the Prospective Cohort with Incident Stroke Berlin (PROSCIS-B) study, we followed participants aged 18 and older for 3 years after first mild to moderate ischemic stroke event or until occurrence of recurrent stroke, myocardial infarction, or all-cause mortality. We compared high coagulation factor activity levels to normal and low levels and also analyzed activities as continuous variables. We used Cox proportional hazards models adjusted for age, sex, and cardiovascular risk factors to estimate hazard ratios (HRs) for the combined endpoint.

RESULTS

In total, 94 events occurred in 576 included participants, resulting in an absolute rate of 6.6 events per 100 person-years. After confounding adjustment, high FVIII activity showed the strongest relationship with the combined endpoint (HR = 2.05, 95% confidence interval [CI] 1.28-3.29). High FXI activity was also associated with a higher hazard (HR = 1.80, 95% CI 1.09-2.98), though high FXII activity was not (HR = 0.86, 95% CI 0.49-1.51). Continuous analyses yielded similar results.

CONCLUSIONS

In our study of mild to moderate ischemic stroke patients, high activity levels of FXI and FVIII but not FXII were associated with worse vascular outcomes in the 3-year period after first ischemic stroke.

Coagulation factor VIII, white matter hyperintensities and cognitive function: Results from the Cardiovascular Health Study

OBJECTIVE

To investigate the relationship between high FVIII clotting activity (FVIII:C), MRI-defined white matter hyperintensities (WMH) and cognitive function over time.

METHODS

Data from the population-based Cardiovascular Health Study (n = 5,888, aged ≥65) were used. FVIII:C was measured in blood samples taken at baseline. WMH burden was assessed on two cranial MRI scans taken roughly 5 years apart. Cognitive function was assessed annually using the Modified Mini-Mental State Examination (3MSE) and Digit Symbol Substitution Test (DSST). We used ordinal logistic regression models adjusted for demographic and cardiovascular factors in cross-sectional and longitudinal WMH analyses, and adjusted linear regression and linear mixed models in the analyses of cognitive function.

RESULTS

After adjustment for confounding, higher levels of FVIII:C were not strongly associated with the burden of WMH on the initial MRI scan (OR>p75 = 1.20, 95% CI 0.99-1.45; N = 2,735) nor with WMH burden worsening over time (OR>p75 = 1.18, 95% CI 0.87-1.59; N = 1,527). High FVIII:C showed no strong association with cognitive scores cross-sectionally (3MSE>p75 β = -0.06, 95%CI -0.45 to 0.32, N = 4,005; DSST>p75 β = -0.69, 95%CI -1.52 to 0.13, N = 3,954) or over time (3MSE>p75 β = -0.07,95% CI -0.58 to 0.44, N = 2,764; DSST>p75 β = -0.22, 95% CI -0.97 to 0.53, N = 2,306) after confounding adjustment.

INTERPRETATION

The results from this cohort study of older adult participants indicate no strong relationships between higher FVIII:C levels and WMH burden or cognitive function in cross-sectional and longitudinal analyses.

Preceding infection and risk of stroke: An old concept revived by the COVID-19 pandemic

Anecdotal reports and clinical observations have recently emerged suggesting a relationship between COVID-19 disease and stroke, highlighting the possibility that infected individuals may be more susceptible to cerebrovascular events. In this review we draw on emerging studies of the current pandemic and data from earlier, viral epidemics, to describe possible mechanisms by which SARS-CoV-2 may influence the prevalence of stroke, with a focus on the thromboinflammatory pathways, which may be perturbed. Some of these potential mechanisms are not novel but are, in fact, long-standing hypotheses linking stroke with preceding infection that are yet to be confirmed. The current pandemic may present a renewed opportunity to better understand the relationship between infection and stroke and possible underlying mechanisms.

Association of Factor V Leiden With Subsequent Atherothrombotic Events: A GENIUS-CHD Study of Individual Participant Data

BACKGROUND

Studies examining the role of factor V Leiden among patients at higher risk of atherothrombotic events, such as those with established coronary heart disease (CHD), are lacking. Given that coagulation is involved in the thrombus formation stage on atherosclerotic plaque rupture, we hypothesized that factor V Leiden may be a stronger risk factor for atherothrombotic events in patients with established CHD.

METHODS

We performed an individual-level meta-analysis including 25 prospective studies (18 cohorts, 3 case-cohorts, 4 randomized trials) from the GENIUS-CHD (Genetics of Subsequent Coronary Heart Disease) consortium involving patients with established CHD at baseline. Participating studies genotyped factor V Leiden status and shared risk estimates for the outcomes of interest using a centrally developed statistical code with harmonized definitions across studies. Cox proportional hazards regression models were used to obtain age- and sex-adjusted estimates. The obtained estimates were pooled using fixed-effect meta-analysis. The primary outcome was composite of myocardial infarction and CHD death. Secondary outcomes included any stroke, ischemic stroke, coronary revascularization, cardiovascular mortality, and all-cause mortality.

RESULTS

The studies included 69 681 individuals of whom 3190 (4.6%) were either heterozygous or homozygous (n=47) carriers of factor V Leiden. Median follow-up per study ranged from 1.0 to 10.6 years. A total of 20 studies with 61 147 participants and 6849 events contributed to analyses of the primary outcome. Factor V Leiden was not associated with the combined outcome of myocardial infarction and CHD death (hazard ratio, 1.03 [95% CI, 0.92-1.16]; I2=28%; P-heterogeneity=0.12). Subgroup analysis according to baseline characteristics or strata of traditional cardiovascular risk factors did not show relevant differences. Similarly, risk estimates for the secondary outcomes including stroke, coronary revascularization, cardiovascular mortality, and all-cause mortality were also close to identity.

CONCLUSIONS

Factor V Leiden was not associated with increased risk of subsequent atherothrombotic events and mortality in high-risk participants with established and treated CHD. Routine assessment of factor V Leiden status is unlikely to improve atherothrombotic events risk stratification in this population.

Normal-range thyroid-stimulating hormone levels and cardiovascular events and mortality in type 2 diabetes

AIMS

Thyroid dysfunction is a risk factor for cardiovascular disease. Whether thyroid function within the normal range is a risk factor for cardiovascular disease remains uncertain. The aim of this study is to evaluate whether plasma thyroid-stimulating hormone (TSH) levels in the normal range are a risk factor for cardiovascular disease and mortality in participants with type 2 diabetes mellitus with high cardiovascular risk.

METHODS

We included 1265 participants with high cardiovascular risk, type 2 diabetes, and TSH within the normal range (0.35-5.00 mIU/L) from the Second Manifestations of ARTerial disease cohort. The primary outcome was major cardiovascular events (MACE; vascular death, stroke and myocardial infarction). Secondary outcomes of interest were the separate vascular outcomes and all-cause mortality. Cox proportional hazard models were used to evaluate the risk of plasma TSH levels on all outcomes.

RESULTS

A total of 191 MACE occurred during a total follow-up of 8183 years. Plasma TSH levels were not associated with MACE (hazard ratio (HR) per mIU/L TSH increase 0.93; 95% confidence interval (95%CI) 0.80-1.08). With a total of 54 strokes during the study period, plasma TSH was associated with a lower risk of stroke (HR per mIU/L 0.64, 95% CI 0.45-0.89). There was no association between plasma TSH levels and risk of myocardial infarction, vascular death, or all-cause mortality.

CONCLUSIONS

Higher TSH levels within the normal range are associated with a lower risk of stroke in high-risk patients with type 2 diabetes, but not associated with the risk of other cardiovascular events or mortality.

A Population-Based Study of Incidence, Presentation, Management and Outcome of Primary Thromboembolic Ischemia in the Upper Extremity

OBJECTIVES

To investigate the epidemiology of acute upper limb thromboembolism in a well-defined Norwegian population.

METHODS

This study was a retrospective, single-center, observational population-based cohort study of acute upper limb thromboembolism. The study included all patients from the hospital's primary catchment area from January 2000 to December 2015. Age- and gender-adjusted incidence rates were calculated using population demographics from Statistics Norway.

RESULTS

A total of 54 patients were identified, of which 49 were included in the analyses: 27 (55%) females (median age 83 years, range 40-96) and 22 (45%) males (median age 70 years, range 42-95) (P = .053). The adjusted incidence rate for the period was 1.6 patients per 100,000 inhabitants per year (95% confidence interval 1.2-2.2) and did not change significantly during the period studied. Atrial fibrillation was detected by electrocardiography in 30 (61%) patients; in this group, 10 patients were on warfarin but only two had an international normalized ratio > 1.9 and the remaining 20 were not anticoagulated. Altogether, 38 (78%) patients underwent surgery, 1 (2%) was treated with thrombolysis, and the remaining patients were treated conservatively; no amputations were performed. Four patients (8%) died within 30 days, and 12 of the surviving 45 patients (27%) had recurrent thromboembolism.

CONCLUSION

The incidence rate was stable during the study period. Patients with upper limb thromboembolism due to atrial fibrillation were inadequately anticoagulated. One in four patients experienced a recurrent thromboembolic event. Lifelong anticoagulation should be considered in all patients with upper limb thromboembolism.

Effect of prothrombotic genotypes on the risk of venous thromboembolism in patients with and without ischemic stroke. The Tromsø Study

Essentials Prothrombotic genotypes may agument the risk of venous thromboembolism (VTE) after ischemic stroke. We studied this effect in a case-cohort study using a genetic risk score. In stroke patients, a one-category increase in the genetic risk score was associated with a 50% higher relative risk of VTE. The risk of VTE in stroke patients increased with an increasing number of risk alleles. SUMMARY: Background Patients with ischemic stroke have a transiently increased risk of subsequent venous thromboembolism (VTE). Prothrombotic genotypes may augment VTE risk under conditions of high thrombosis risk related to stroke. Aims To investigate the effect of prothrombotic genotypes in patients with ischemic stroke on the risk of VTE in a population-based case-cohort study. Methods Cases with incident VTE (n = 664) and a randomly selected age-weighted subcohort (n = 1817) were sampled from three surveys of the Tromsø Study (1994-2008). Participants were genotyped for ABO (rs8176719), F5 (rs6025), F2 (rs1799963), FGG (rs2066865) and F11 (rs2036914) single-nucleotide polymorphisms (SNPs). Cox regression models were used to calculate hazard ratios (HRs) for incident VTE according to individual SNPs and categories of risk alleles (5-SNP score; 0-1, 2, 3-4 and ≥ 5) in participants with and without ischemic stroke. Results There were 192 patients with incident stroke, of whom 43 developed VTE during a median of 15.2 years of follow-up. The risk alleles of individual SNPs augmented the elevated VTE risk brought about by ischemic stroke. In stroke patients, a one-category increase in the genetic risk score was associated with a 50% higher relative risk of overall VTE (HR 1.5, 95% confidence interval [CI] 1.3-1.8) and an 80% higher relative risk of provoked VTE (HR 1.8, 95% CI 1.5-2.1). Stroke patients with ≥ 5 risk alleles had a 12-fold (HR 11.7, 95% CI 4.1-33.3) higher relative risk of VTE than stroke-free participants with 0-1 risk alleles. Conclusions Prothrombotic genotypes increased the risk of VTE in stroke patients, and the risk increased with an increasing number of risk alleles.

Hypercoagulability and the risk of recurrence in young women with myocardial infarction or ischaemic stroke: a cohort study

Background

We aimed to investigate the role of hypercoagulability on the risk of lifetime cardiovascular recurrences after myocardial infarction or ischaemic stroke.

Methods

Young women (< 50 years) with either myocardial infarction (n = 197) or ischaemic stroke (n = 107) were followed between 1995 and 2012 in the RATIO follow-up study. To determine whether hypercoagulability affects the risk or recurrence, a coagulation score based on acquired and inherited markers was compiled and used in a quartile analysis. Hazard ratios (HRs) obtained from Cox proportional models and adjusted for several cardiovascular risk factors were used to compare quartiles of the coagulation score for the risk of recurrence.

Results

During a median follow-up of 19 years, 59 cardiovascular recurrences occurred. In patients with myocardial infarction no association was found between a high prothrombotic score and recurrences (highest quartile vs lowest quartile HR 0.7, 95% CI, 0.3–1.8). Conversely, ischaemic stroke patients with a high prothrombotic score showed a doubling in risk of long-term cardiovascular recurrences (HR 1.9, 95% CI 0.6–6.3) compared with ischaemic stroke patients and low levels of the score, with a dose response relationship.

Conclusions

An increased coagulation tendency might be associated with long-term cardiovascular risk in women with ischaemic stroke, but not in women with myocardial infarction.

Genetic determinants of activity and antigen levels of contact system factors

Essentials Genetic variation may provide valuable insight into the role of the contact system in thrombosis. Explored associations of genetic variants with activity, antigen, and disease in RATIO study. Two novel loci were identified: KLKB1 rs4253243 for prekallikrein; KNG1 rs5029980 for HMWK levels. Contact system variants and haplotypes were not associated with myocardial infarction or stroke. SUMMARY: Background The complex, interdependent contact activation system has been implicated in thrombotic disease, although few genetic determinants of levels of proteins from this system are known. Objectives Our primary aim was to study the influence of common F11, F12, KLKB1, and KNG1 variants on factor (F) XI activity and FXI, FXII, prekallikrein (PK) and high-molecular-weight kininogen (HMWK) antigen levels, as well as the risk of myocardial infarction and ischemic stroke. Patients/methods We analyzed samples from all 630 healthy participants, 182 ischemic stroke patients and 216 myocardial infarction patients in the RATIO case-control study of women aged < 50 years. Forty-three tagging single nucleotide variants (SNVs) were genotyped to represent common genetic variation in the contact system genes. Antigen and activity levels were measured with sandwich-ELISA-based and one-stage clotting assays. We performed single variant, age-adjusted, linear regression analyses per trait and disease phenotype, assuming additive inheritance and determined conditionally independent associations. Haplotypes based on the lead SNV and all conditionally independent SNVs were tested for association with traits and disease. Results We identified two novel associations of KLKB1 SNV rs4253243 with PK antigen (βconditional = -12.38; 95% CI, -20.07 to -4.69) and KNG1 SNV rs5029980 with HMWK antigen (βconditional = 5.86; 95% CI, 2.40-9.32) and replicated previously reported associations in a single study. Further analyses probed whether the observed associations were indicative of linkage, pleiotropic effects or mediation. No individual SNVs or haplotypes were associated with the disease outcomes. Conclusion This study adds to current knowledge of how genetic variation influences contact system protein levels and clarifies interdependencies.

Correlative Light-Electron Microscopy detects lipopolysaccharide and its association with fibrin fibres in Parkinson's Disease, Alzheimer's Disease and Type 2 Diabetes Mellitus

Many chronic diseases, including those classified as cardiovascular, neurodegenerative, or autoimmune, are characterized by persistent inflammation. The origin of this inflammation is mostly unclear, but it is typically mediated by inflammatory biomarkers, such as cytokines, and affected by both environmental and genetic factors. Recently circulating bacterial inflammagens such as lipopolysaccharide (LPS) have been implicated. We used a highly selective mouse monoclonal antibody to detect bacterial LPS in whole blood and/or platelet poor plasma of individuals with Parkinson’s Disease, Alzheimer’s type dementia, or Type 2 Diabetes Mellitus. Our results showed that staining is significantly enhanced (P < 0.0001) compared to healthy controls. Aberrant blood clots in these patient groups are characterized by amyloid formation as shown by the amyloid-selective stains thioflavin T and Amytracker™ 480 or 680. Correlative Light-Electron Microscopy (CLEM) illustrated that the LPS antibody staining is located in the same places as where amyloid fibrils may be observed. These data are consistent with the Iron Dysregulation and Dormant Microbes (IDDM) hypothesis in which bacterial inflammagens such as LPS are responsible for anomalous blood clotting as part of the aetiology of these chronic inflammatory diseases.

Risk factors and mechanisms of stroke in young adults: The FUTURE study

Incidence of ischemic stroke and transient ischemic attack in young adults is rising. However, etiology remains unknown in 30-40% of these patients when current classification systems designed for the elderly are used. Our aim was to identify risk factors according to a pediatric approach, which might lead to both better identification of risk factors and provide a stepping stone for the understanding of disease mechanism, particularly in patients currently classified as "unknown etiology". Risk factors of 656 young stroke patients (aged 18-50) of the FUTURE study were categorized according to the "International Pediatric Stroke Study" (IPSS), with stratification on gender, age and stroke of "unknown etiology". Categorization of risk factors into ≥1 IPSS category was possible in 94% of young stroke patients. Chronic systemic conditions were more present in patients aged <35 compared to patients ≥35 (32.6% vs. 15.6%, p < 0.05). Among 226 patients classified as "stroke of unknown etiology" using TOAST, we found risk factors in 199 patients (88%) with the IPSS approach. We identified multiple risk factors linked to other mechanisms of stroke in the young than in the elderly . This can be a valuable starting point to develop an etiologic classification system specifically designed for young stroke patients.

Impact of Chronic Inflammation, Assessed by hs-CRP, on the Association between Red Cell Distribution Width and Arterial Cardiovascular Disease: The Tromsø Study

Red cell distribution width (RDW), a measure of variability in size of circulating erythrocytes, is associated with arterial cardiovascular disease (CVD), but the underlying mechanism remains unclear. We aimed to investigate the impact of chronic inflammation as measured by high-sensitivity C-reactive protein (hs-CRP) on this relationship, and explore whether RDW could be a mediator in the causal pathway between inflammation and arterial CVD. Baseline characteristics, including RDW and hs-CRP, were obtained from 5,765 individuals attending a population-based cohort study. We followed up participants from inclusion in the fourth survey of the Tromsø Study (1994/1995) until December 31, 2012. Multivariable Cox-regression models were used to calculate hazard ratios (HR) with 95% confidence intervals (CI) for incident myocardial infarction (MI) and ischemic stroke across quintiles of hs-CRP and RDW. Subjects with hs-CRP in the highest quintile had 44% higher risk of MI (HR: 1.44, 95% CI: 1.14-1.80), and 64% higher risk of ischemic stroke (HR: 1.64, 95% CI: 1.20-2.24) compared with subjects in the lowest quintile. RDW mediated 7.2% (95% CI: 4.0-30.8%) of the association between hs-CRP and ischemic stroke. Subjects with RDW in the highest quintile had 22% higher risk of MI (HR: 1.22, 95% CI: 0.98-1.54) and 44% higher risk of ischemic stroke (HR: 1.44, 95% CI: 1.06-1.97) compared with subjects in the lowest quintile. These risk estimates were slightly attenuated after adjustments for hs-CRP. Our findings suggest that chronic inflammation is not a primary mechanism underlying the relationship between RDW and arterial CVD.

Blood Coagulation Following an Acute Ischemic Stroke

Objective. Hemostasis is a complex physiological process that stops bleeding at the site of a vascular injury. Although the majority of vascular accidents are ischemic, the role of hypercoagulable state and stroke needs further investigation. Materials and Methods. Fresh whole blood was taken from 61 acute ischemic stroke patients and compared to 18 healthy subjects and investigated with optical coherence tomography imaging after initiating coagulation. We used an OCT1300SS system (Thorlabs) and did 3D scans. We then processed the images with ImageJ. For each image mean, integrated density, skewness and kurtosis of gray values were analyzed. Results. Mean gray value and integrated intensity of sampled data showed an intrinsic difference detected with OCT. This difference was further confirmed by the data distribution analysis. Conclusions. Results suggest, that normal blood coagulation, is not a random reaction while in the case of stroke patients, the relatively symmetrical distribution of gray values brings coagulation closer randomized process.

Coagulation Profile as a Risk Factor for 30-day Morbidity Following Cervical Laminectomy and Fusion

STUDY DESIGN

Retrospective analysis of prospectively collected data.

OBJECTIVE

The aim of this study was to determine the ability of abnormal coagulation profile to predict adverse events following posterior cervical laminectomy and fusion (PCLF).

SUMMARY OF BACKGROUND DATA

PCLF is an increasingly common procedure used to treat a variety of traumatic and degenerative spinal conditions. Abnormal coagulation profile is associated with postoperative adverse events, including blood transfusion. There is a paucity of literature that specifically addresses the relationship between coagulation profile and complications following PCLF.

METHODS

ACS-NSQIP was utilized to identify patients undergoing PCLF between 2006 and 2013. A total of 3546 patients met inclusion criteria. Multivariate analysis was utilized to identify associations between abnormal coagulation profile and postoperative complications.

RESULTS

Membership in the low-platelet cohort was an independent risk factor for myocardial infarction (Odds Ratio (OR) = 5.4 [1.0, 29.1], P = 0.049) and bleeding transfusion (OR = 2.0 [1.2, 3.4], P = 0.011). Membership in the high international normalized ratio group was an independent risk factor for pneumonia (OR = 6.3 [2.5, 16.1], P < 0.001), ventilation >48 hours (OR = 6.5 [2.3, 18.4], P < 0.001), organ space surgical site infection (OR = 11.1 [2.1, 57.3], P = 0.004), urinary tract infection (OR = 3.0 [1.2, 8.0], P = 0.024), bleeding transfusion (OR = 6.0 [3.4, 10.7], P < 0.001), sepsis (OR = 5.1 [1.6, 16.4], P = 0.006), and septic shock (OR = 6.8 [1.7, 27.4], P = 0.007). Membership in the bleeding disorders cohort was an independent predictor of unplanned intubation (OR = 3.2 [1.1, 9.5], P = 0.041), pneumonia (OR = 2.9 [1.2, 7.2], P = 0.023), ventilation >48 hours (OR = 4.8 [1.9, 12.4], P = 0.001), cerebrovascular accident/stroke with neurological deficit (OR = 24.8 [2.9, 210.6], P = 0.003), bleeding transfusion (OR = 2.1 [1.1, 4.1], P = 0.032), reoperation (OR = 3.6 [1.4, 9.3], P = 0.008), and sepsis (OR = 3.4 [1.1, 10.4], P = 0.031).

CONCLUSION

This is the first large study to document abnormal coagulation profile as an independent predictor of outcomes following PCLF. Abnormal coagulation profile represents a predictor of complications that can be medically mitigated, and is therefore a valuable parameter to assess preoperatively. Coagulation profile should continue to play a role in targeting patients for risk stratification, preoperative optimization, and quality improvement initiatives.

LEVEL OF EVIDENCE

3.

Neuroendocrine System Regulatory Mechanisms: Acute Coronary Syndrome and Stress Hyperglycaemia

Neurohormonal systems are activated in the early phase of acute coronary syndromes to preserve circulatory homeostasis, but prolonged action of these stress hormones might be deleterious. Cortisol reaches its peak at 8 hours after the onset of symptoms, and individuals who have continued elevated levels present a worse prognosis. Catecholamines reach 100-1,000-fold their normal plasma concentration within 30 minutes of ischaemia, therefore inducing the propagation of myocardial damage. Stress hyperglycaemia induces inflammation and endothelial dysfunction, and also has procoagulant and prothrombotic effects. Patients with hyperglycaemia and no diabetes elevated in-hospital and 12-month mortality rates. Hyperglycaemia in patients without diabetes has been shown to be an appropriate independent mortality prognostic factor in this type of patient.

A Prothrombotic Score Based on Genetic Polymorphisms of the Hemostatic System Differs in Patients with Ischemic Stroke, Myocardial Infarction, or Peripheral Arterial Occlusive Disease

Background

While twin studies indicate a genetic component in arterial thrombosis such as ischemic stroke, myocardial infarction (MI), or peripheral arterial occlusive disease (PAOD), the clinical relevance of hemostatic polymorphisms in arterial thrombosis is a matter of debate.

Methods

We analyzed the prevalence of 13 hemostatic polymorphisms [PAI-1, PLAT, F5 (including factor V Leiden and HR2 haplotype), F2, F7, F13A, FGB, TFPI, THBD, MTHFR, ACE, and ITGA2] in patients referred to a tertiary referral center. A “prothrombotic score” was calculated by dividing the number of risk-increasing polymorphisms for thrombosis minus the number of risk-lowering polymorphisms (F7 and F13A) by the number of polymorphisms tested.

Results

Datasets of 144 patients with prior ischemic stroke (mean age 44 ± 13 years; 65% female) were compared to 62 patients with MI or PAOD (mean age 54 ± 14 years; 47% female). The prothrombotic score was lower in MI and PAOD patients compared to stroke patients [odds ratios 2.7 (95% confidence intervals 1.1–6.2)]. Frequencies of individual polymorphisms did not differ between both groups.

Conclusion

Patients with MI or PAOD had a lower burden of prothrombotic mutations compared to patients with prior stroke, indicating that a prothrombotic state might play a different role in distinct forms of arterial thrombosis.

Contribution of Established Stroke Risk Factors to the Burden of Stroke in Young Adults

BACKGROUND AND PURPOSE

As stroke in young adults is assumed to have different etiologies and risk factors than in older populations, the aim of this study was to examine the contribution of established potentially modifiable cardiovascular risk factors to the burden of stroke in young adults.

METHODS

A German nationwide case-control study based on patients enrolled in the SIFAP1 study (Stroke In Young Fabry Patients) 2007 to 2010 and controls from the population-based GEDA study (German Health Update) 2009 to 2010 was performed. Cases were 2125 consecutive patients aged 18 to 55 years with acute first-ever stroke from 26 clinical stroke centers; controls (age- and sex-matched, n=8500, without previous stroke) were from a nationwide community sample. Adjusted population-attributable risks of 8 risk factors (hypertension, hyperlipidemia, diabetes mellitus, coronary heart disease, smoking, heavy episodic alcohol consumption, low physical activity, and obesity) and their combinations for all stroke, ischemic stroke, and primary intracerebral hemorrhage were calculated.

RESULTS

Low physical activity and hypertension were the most important risk factors, accounting for 59.7% (95% confidence interval, 56.3-63.2) and 27.1% (95% confidence interval, 23.6-30.6) of all strokes, respectively. All 8 risk factors combined explained 78.9% (95% confidence interval, 76.3-81.4) of all strokes. Population-attributable risks of all risk factors were similar for all ischemic stroke subtypes. Population-attributable risks of most risk factors were higher in older age groups and in men.

CONCLUSIONS

Modifiable risk factors previously established in older populations also account for a large part of stroke in younger adults, with 4 risk factors explaining almost 80% of stroke risk.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00414583.

Ischemic Stroke and Risk of Venous Thromboembolism in the General Population: The Tromsø Study

Background

Even though clinical data support a relation between ischemic stroke and venous thromboembolism (VTE), the strength and time dependence of the association remain to be settled at the population level. We therefore aimed to investigate the association between ischemic stroke and VTE in a prospective population‐based cohort.

Methods and Results

Participants (n=30 002) were recruited from 3 surveys of the Tromsø study (conducted in 1994–1995, 2001, and 2007–2008) and followed through 2010. All incident events of ischemic stroke and VTE during follow‐up were recorded. Cox‐regression models with age as time scale and ischemic stroke as a time‐dependent variable were used to calculate hazard ratios (HR) of VTE adjusted for cardiovascular risk factors. During a median follow‐up time of 15.7 years, 1360 participants developed ischemic stroke and 722 had a VTE. The risk of VTE was highest the first month (HR 19.7; 95% CI, 10.1–38.5) and from 1 to 3 months after the stroke (HR 10.6; 95% CI 5.0–22.5), but declined rapidly thereafter. The risk estimates were approximately the same for deep vein thrombosis (HR 19.1; 95% CI, 7.8–38.5), and pulmonary embolism (HR 20.2; 95% CI, 7.4–55.1). Stroke was associated with higher risk for provoked (HR 22.6; 95% CI, 12.5–40.9) than unprovoked VTE (HR 7.4; 95% CI, 2.7–20.1) the first 3 months.

Conclusions

The risk of VTE increased during the first 3 months after an ischemic stroke. The particularly high risk of provoked VTE suggests that additional predisposing factors, such as immobilization, potentiate the VTE risk in patients with ischemic stroke.

Low ADAMTS-13 activity and the risk of coronary heart disease - a prospective cohort study: the Rotterdam Study

Essentials An association between ADAMTS-13 and coronary heart disease (CHD) has been suggested. 5688 participants ≥ 55 years from the Rotterdam Study without a history of CHD were included. Over a median follow-up time of 9.7 years, 456 individuals suffered from CHD. Low ADAMTS-13 activity was associated with an increased CHD risk.

SUMMARY

Background The metalloprotease ADAMTS-13 cleaves high-molecular-weight von Willebrand factor multimers into smaller, less procoagulant forms. Low ADAMTS-13 activity is associated with an increased risk of ischemic stroke but its pathogenic role in coronary heart disease (CHD) is unclear. Objectives We aimed to determine the association between ADAMTS-13 activity and the risk of CHD in a large prospective population-based cohort study. Methods A total of 5688 participants of the Rotterdam Study, a population-based cohort study involving individuals aged ≥ 55 years without a history of CHD, were included. ADAMTS-13 activity was measured by the FRETS-VWF73 assay and VWF:Ag levels by ELISA. We assessed the association between ADAMTS-13 activity, VWF:Ag levels and CHD using Cox proportional hazard regression analysis, adjusting for cardiovascular risk factors. Results Over a median follow-up time of 9.7 years, 456 individuals suffered from CHD. A low ADAMTS-13 activity (quartile 1) was associated with an increased CHD risk (HR 1.42, 95% CI 1.07-1.89) compared with the reference highest quartile. Conclusions Low ADAMTS-13 activity is associated with an increased risk of CHD in the elderly, independently of VWF and established cardiovascular risk factors.

Ischemic stroke in the young: Current perspectives on incidence, risk factors, and cardiovascular prognosis

About one-fourth of ischemic strokes occur in working-aged individuals in the high-income countries, with worldwide increasing incidence in this age group from 1980s to present. Recent evidence suggests that traditional vascular risk factors are more prevalent than previously suggested in young adult stroke patients and they accumulate with age particularly in men. Accordingly, relatively high rates of atherosclerotic changes have been detected in these patients. The strength of association of vascular risk factors has gone poorly studied, however. Many young patients with ischemic stroke have, in turn, no traditional risk factors, while they may harbor other conditions with weak or uncertain association with the stroke alone. These individual conditions often represent a risk factor that may be strictly young-age specific, more prevalent in younger than older stroke patients (e.g. patent foramen ovale), or more prevalent among the young in the population. Despite high rates of vascular risk factors and atherosclerotic changes, these findings do not translate to higher frequencies of identified classical stroke mechanisms. In fact, cryptogenic causes are markedly common and even more frequent among the very young patients. Limited randomized trial evidence exists to support secondary prevention decision-making in patients, yet they face an increased risk of death and future vascular events for years to come-dependent on risk factor profile and cause of the stroke. This review provides an overview of recent data on epidemiology, risk factors, and their strength of association in ischemic stroke in the young. Furthermore, the relationship between with the risk factors and cardiovascular outcomes and key features on the evidence related to secondary prevention will be discussed.

Low ADAMTS13 activity is associated with an increased risk of ischemic stroke

ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin motif repeats 13) has antithrombotic properties because it cleaves von Willebrand factor (VWF) in smaller, less active multimers. The aim of our study was to investigate prospectively the association between ADAMTS13 activity and ischemic stroke. We included 5941 individuals ≥55 years without a history of stroke or transient ischemic attack (TIA) of the Rotterdam Study, a population-based cohort study. ADAMTS13 activity was measured at inclusion with the FRETS-VWF73 assay and VWF antigen (VWF:Ag) levels by enzyme-linked immunosorbent assay. We assessed the association among ADAMTS13 activity, VWF:Ag levels, and ischemic stroke by Cox proportional hazard analysis. The added value of ADAMTS13 activity above the traditional risk factors for ischemic stroke risk prediction was examined by the C-statistic and the net reclassification improvement index (NRI). All individuals were followed for incident stroke or TIA. Over a median follow-up time of 10.7 years (56,403 total person-years), 461 participants had a stroke, 306 of which were ischemic. After adjustment for cardiovascular risk factors, individuals with ADAMTS13 activity in the lowest quartile had a higher risk of ischemic stroke (absolute risk, 7.3%) than did those in the reference highest quartile (absolute risk, 3.8%; hazard ratio, 1.65; 95% confidence interval [CI], 1.16-2.32). Adding ADAMTS13 to the model in prediction of ischemic stroke, increased the C-statistic by 0.013 (P = .003) and provided 0.058 (95% CI, -0.002 to 0.119) NRI. Low ADAMTS13 activity is associated with the risk of ischemic stroke and improves the accuracy of risk predictions for ischemic stroke beyond traditional risk factors.