Can haematological tests predict cardiovascular risk? The 2005 Kettle Lecture*

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.

Midlife Hemostasis Measures, 20-Year Cognitive Decline, and Incident Dementia

BACKGROUND AND OBJECTIVES

Blood concentrations of hemostatic factors affect thrombosis and bleeding diathesis and may contribute to cognitive impairment through modifiable vascular pathologies. Whether hemostasis, assessed in middle age, is associated with late-life cognitive impairment remains largely unknown in a community-dwelling population.

METHODS

Using data from 14,128 participants with cognitive function measurements in 1990-1992 from the Atherosclerosis Risk in Communities study, we assessed the associations of hemostasis measures with 20-year changes in cognitive performance and incident dementia. Activated partial thromboplastin time (aPTT) and level of fibrinogen, von Willebrand factor (VWF), factor VIII, factor VII, factor XI, d-dimer, and soluble thrombomodulin were measured in 1987-1989 or 1993-1995. Hemostasis measures were categorized into quintiles, with the lowest quintile indicating low coagulability. Cognitive performance was characterized using a combined z-score from 3 tests (that is, delayed word recall test [DWRT], digit symbol substitution [DSST], and word fluency test [WFT]), assessed in 1990-1992, 1996-1998, and 2011-2013. Dementia was determined either from in-person evaluations or using dementia surveillance through 2017. Mixed-effects models and Cox proportional hazards models were used to assess cognitive trajectories and risk of dementia, respectively.

RESULTS

Among 12,765 participants with hemostasis measures in 1987-1989, who were aged 47-70 years at the first cognitive assessment, we observed significant trends of shorter aPTT (p for trend <0.001; difference in 20-year cognitive decline for fifth vs first quintile [Q5 vs Q1]: -0.104 [95% CI -0.160 to -0.048]) and higher levels of factor VII (p < 0.002; Q5 vs Q1: -0.085 [-0.142, -0.028]) and factor VIII (p = 0.033; Q4 vs Q1: -0.055 [-0.111, -0.000]) with greater 20-year cognitive declines. The associations with the decline in DSST were stronger than those with the decline in WFT or DWRT. Consistently, shorter aPTT and higher factor VIII levels were associated with higher dementia risk with HRs for Q5 vs Q1 of 1.23 (95% CI 1.07 to 1.42) and 1.17 (1.01-1.36), respectively, and p for trend of 0.008 and 0.024, respectively.

DISCUSSION

Overall, our study found consistent trend associations of aPTT and factor VIII measured in midlife with cognitive decline and incident dementia over 20 years, likely driven by vascular pathologies.

Coagulation factors II, V, VII, IX, X and XI and mortality - a cohort study

Background

Elevated levels of coagulation factors (F) II (FII), FV, FVII, FIX, FX, and FXI have often been related with coronary heart disease, ischemic stroke, and venous thrombosis (VT). However, there are few studies on their associations with all-cause mortality.

Objective

We explored whether elevated levels of FII, FV, FVII, FIX, FX, and FXI are associated with an increased risk of death in patients who had VT and in individuals from the general population.

Methods

We followed 1919 patients with previous VT and 2800 age- and sex-matched community controls in whom coagulation factor levels were measured. A high coagulation factor was defined as the >90th percentile of normal in the controls. Cox regression analyses were adjusted for age and sex and for being a patient with VT or being a control subject.

Results

The median age at time of enrolment was 48 years for both patients and controls, and slightly more women than men were followed. Over a median follow-up of 6.1 years for patients and 5.0 years for controls, there were 79 and 60 deaths in patient and controls respectively. There was no association of FII, FV, FVII, FIX, FX, and FXI with all-cause mortality in patients or in control individuals.

Conclusions

Elevated levels of FII, FV, FVII, FIX, FX, and FXI levels may not be associated with an increased risk of all-cause mortality. Only for cardiac death, an association with high FX and FXI was found, which confirms the findings of previous studies, but numbers were small.

Hemostasis from Bench to Bedside: The History of Three Successful Stories of Translational Medicine

Looking at the history of hemostasis, one can easily conclude that most of the achievements we see today have been done through the ingenuity and dedication of scientists, who devoted their efforts to translate the basic concepts behind their hypotheses from the laboratory to the patient bedside. I am personally excited by three of these stories. This article aims to review the history on the development of D-dimer, heparin, and coagulometers, which have been chosen as paradigmatic examples of diagnostic testing, drugs, and measuring devices, respectively. They should be considered among the most successful histories of translational medicine.

Associations of Hemostatic Variables with Cardiovascular Disease and Total Mortality: The Glasgow MONICA Study

The associations of plasma levels of hemostatic factors, other than fibrinogen, with risks of cardiovascular disease (CVD) and all-cause mortality are not well defined. In two phases of the Glasgow MONICA study, we assayed coagulation factors (VII, VIII, IX, and von Willebrand factor), coagulation inhibitors (antithrombin, protein C, protein S), coagulation activation markers (prothrombin fragment 1 + 2, thrombin–antithrombin complexes, D-dimer), and the fibrinolytic factors, tissue plasminogen activator (t-PA) antigen and plasminogen activator inhibitor type 1. Over 15 to 20 years, we followed up between 382 and 1,123 men and women aged 30 to 74 years, without baseline CVD, for risks of CVD and mortality. Age- and sex-adjusted hazard ratios (HRs) for CVD (top third vs bottom third) were significant only for factor VIII (1.30; 95% confidence interval [CI], 1.06–1.58) and factor IX (1.18; 95% CI, 1.01–1.39); these HRs were attenuated by further adjustment for CVD risk factors: 1.17 (95% CI, 0.94–1.46) and 1.07 (95% CI, 0.92–1.25), respectively. In contrast, factor VIII (HR, 1.63; 95% CI, 1.35–1.96), D-dimer (HR, 2.34; 95% CI, 1.26–4.35), and t-PA (HR, 2.81; 95% CI, 1.43–5.54) were strongly associated with mortality after full risk factor adjustment. Further studies, including meta-analyses, are required to assess the associations of these hemostatic factors with the risks of stroke and heart disease and causes of mortality.

ASSOCIATIONS OF HAEMOSTATIC VARIABLES WITH CARDIOVASCULAR DISEASE AND TOTAL MORTALITY - THE GLASGOW MONICA STUDY

The associations of plasma levels of hemostatic factors, other than fibrinogen, with risks of cardiovascular disease (CVD) and all-cause mortality are not well defined. In two phases of the Glasgow MONICA study, we assayed coagulation factors (VII, VIII, IX, and von Willebrand factor), coagulation inhibitors (antithrombin, protein C, protein S), coagulation activation markers (prothrombin fragment 1 + 2, thrombin–antithrombin complexes, D-dimer), and the fibrinolytic factors, tissue plasminogen activator (t-PA) antigen and plasminogen activator inhibitor type 1. Over 15 to 20 years, we followed up between 382 and 1,123 men and women aged 30 to 74 years, without baseline CVD, for risks of CVD and mortality. Age- and sex-adjusted hazard ratios (HRs) for CVD (top third vs bottom third) were significant only for factor VIII (1.30; 95% confidence interval [CI], 1.06–1.58) and factor IX (1.18; 95% CI, 1.01–1.39); these HRs were attenuated by further adjustment for CVD risk factors: 1.17 (95% CI, 0.94–1.46) and 1.07 (95% CI, 0.92–1.25), respectively. In contrast, factor VIII (HR, 1.63; 95% CI, 1.35–1.96), D-dimer (HR, 2.34; 95% CI, 1.26–4.35), and t-PA (HR, 2.81; 95% CI, 1.43–5.54) were strongly associated with mortality after full risk factor adjustment. Further studies, including meta-analyses, are required to assess the associations of these hemostatic factors with the risks of stroke and heart disease and causes of mortality.

D-dimers are associated with coronary artery disease severity assessed using Syntax and Syntax II scores in patients with ST elevation myocardial infarction

INTRODUCTION AND OBJECTIVES

D-dimers are a determinant of hypercoagulable state and have been found to be related to acute coronary syndromes. We aimed to establish the association between increased D-dimer levels and coronary artery disease (CAD) severity using SYNTAX Score (SS) II in patients with ST elevation myocardial infarction (STEMI) who underwent primary percutaneous coronary intervention (PCI).

METHODS

This retrospective study included 300 consecutive patients (81.7% males, mean age 55±12 years) with STEMI who underwent a primary PCI. Patients were divided into two groups according to their median SSII [SSII<25 as a low group (n=151) and SSII≥25 as a high group (n=149)]. Blood samples for D-dimers and the other biochemical parameters were obtained from each patient at admission.

RESULTS

When compared with the low SSII group, frequency of female gender, no-reflow phenomenon, D-dimer levels, thrombus score, creatine kinase MB and troponin were significantly higher, whereas left ventricular ejection fraction (LVEF) and glomerular filtration rate (GFR) were lower in the high SSII group (p<0.05, for all). D-dimer levels, thrombus score, LVEF, GFR and no-reflow phenomenon were independent predictors of CAD severity (p<0.05, for all). Receiver operating characteristic curve analysis showed that the D-dimer cut-off value for predicting the severity of CAD was 0.26 μg/ml (69.8% sensitivity and 65.6% specificity, p<0.001).

CONCLUSION

Increased D-dimer levels are associated with the severity of CAD based on Syntax Score II, in patients with STEMI who successfully underwent revascularization with a primary PCI.

Acute exposure to diesel and sewage biodiesel exhaust causes pulmonary and systemic inflammation in mice

Biodiesel is a renewable energy source that reduces particle emission, but few studies have assessed its effects. To assess the effects of acute inhalation of two doses (600 and 1200 μg/m³) of diesel (DE) and biodiesel (BD) fuels on the inflammatory pulmonary and systemic profile of mice. Animals were exposed for 2 h in an inhalation chamber inside the Container Laboratory for Fuels. Heart rate, heart rate variability (HRV) and blood pressure were determined 30 min after exposure. After 24 h, we analyzed the lung inflammation using bronchoalveolar lavage fluid (BALF); neutrophil and macrophage quantification in the lung parenchyma was performed, and blood and bone marrow biomarkers as well as receptor of endothelin-A (ET-Ar), receptor of endothelin-B (ET-Br), vascular cell adhesion molecule 1 (VCAM-1), inducible nitric oxide synthase (iNOs) and isoprostane (ISO) levels in the pulmonary vessels and bronchial epithelium were evaluated. HRV increased for BD600, D600 and D1200 compared to filtered air (FA). Both fuels (DE and BD) produced alterations in red blood cells independent of the dose. BALF from the BD600 and BD1200 groups showed an increase in neutrophils compared to those of the FA group. Numeric density of the polymorphonuclear and mononuclear cells was elevated with BD600 compared to FA. In the peribronchiolar vessels, there was an increase in ET-Ar and ET-Br expression following BD600 compared to FA; and there was a reduction in the iNOs expression for BD1200 and the VCAM-1 for D1200 compared to FA. In the bronchial epithelium, there was an increase in ETAr at BD600, ET-Br at two doses (600 and 1200 μg/m³) of DE and BD, iNOs at D600 and VCAM-1 at BD1200 and D600; all groups were compared to the FA group. Acute exposure to DE and BD derived from sewage methyl esters triggered pulmonary and cardiovascular inflammatory alterations in mice.

The relevance of coagulation in cardiovascular disease: what do the biomarkers tell us?

Several haemostatic factors have been associated with incident arterial cardiovascular disease in prospective studies and meta-analyses. Plasma fibrinogen shows a strong and consistent association with risk; however, this may reflect its inflammatory marker status, and causality remains to be proven. The common haemostatic gene polymorphisms for factor II, factor V and the von Willebrand factor: Factor VIII (non-O blood group) show significant associations with coronary heart disease (CHD) risk, consistent with potential causality. Increased D-dimer and t-PA antigen levels are associated with CHD risk, suggesting roles for coagulation activation and endothelial disturbance. There is little evidence for associations with CVD with other haemostatic factors.

Hyperglycaemia, oxidative stress and inflammatory markers

INTRODUCTION

The increasing prevalence of hyperglycaemia implicates a state of oxidative stress and inflammation. Traditional and emerging biomarkers associated with increasing hyperglycaemia were assessed to clarify their role they play in hyperglycaemia.

RESULTS

309 participants attending a rural diabetic screening program were categorised into control and quintile groups based upon glucose levels: 1st quintile - <4.5 mmol/L and 4th, 5th quintile - >6.1 mmol/L. Significant results were obtained for anthropometric data and biochemical markers - glucose, HbA1c and total cholesterol (P < 0.001); oxidative stress: glutathione (P < 0.001), glutathione:glutathione disulfide and 8-hydroxy-2-deoxyguanosine (P < 0.05). Interleukin -1β and inflammatory marker ratios IL-6/IL-10, IL-1β/IL-10, MCP-1/IL-10, IGF-1/IL-10 and IL-6/IL-1β were significant (P < 0.05).

CONCLUSION

This study provided further evidence that inflammatory and oxidative stress biomarkers may contribute to diagnostic information associated with preclinical increases in BGL. Further we have provided a unique study in the analysis of ratios of inflammatory biomarkers and correlations with increasing BGL.

Update on the Cardiovascular Risks of Hormone Replacement Therapy

Systematic reviews of randomized, controlled trials have shown that use of hormone replacement therapy in women increases the risk of total cardiovascular disease (venous thromboembolism, stroke and coronary heart disease; there may also be an increased risk of peripheral arterial disease). The relative increase in risk is similar to that for use of combined oral contraceptives, but the absolute increase in risk is higher owing to the higher age of hormone replacement therapy users. The increased risk appears confined to current users, increases with age and obesity, and may differ with type of preparation. Transdermal hormone replacement therapy may carry a lower risk of venous thromboembolism compared with oral hormone replacement therapy. The mechanism for the increased risk is probably activated blood coagulation. The risk of venous thromboembolism is higher in women with thrombophilias; however, the value of screening for thrombophilias is not established. Further research is required to establish the risks of cardiovascular (and other) diseases in different groups of women for different types of hormone replacement therapy, including an individual participant meta-analysis of reported randomized, controlled trials.

Plasma d-Dimer as a Useful Marker Predicts Severity of Atherosclerotic Lesion and Short-Term Outcome in Patients With Coronary Artery Disease

Increased d-dimer is indicative of a hypercoagulable state and found to be associated with acute coronary syndromes. The present study aimed to evaluate whether plasma d-dimer levels could predict subsequent major clinical events in patients with coronary artery disease (CAD). First, 2209 angiographic-proven patients with CAD were consecutively enrolled. Then, all patients were subjected to follow up for an average of 18 months (ranged from 14 to 1037 days). The relationships of the plasma d-dimer with the severity of CAD and future clinical outcomes were evaluated. We found that plasma d-dimer was higher in patients with prior myocardial infarction (MI) than that in patients with nonprior MI (P = .006). Multivariate linear regression analysis suggested that the plasma d-dimer was linked to the severity of CAD assessed by Gensini score (β = 0.052, 95% confidence interval [CI]: 1.20-6.84, P = .005) even after adjusting for confounding factors. During the follow-up, 42 patients underwent prespecified outcomes. After adjustment for multiple variables in the Cox regression model, the d-dimer levels remained to be a potential predictor of total outcome (hazard ratio = 1.22, 95% CI: 1.09-1.37, P = .001). Therefore, plasma d-dimer levels appeared to be a useful predictor for the severity of CAD and the subsequent major clinical events.

Prospective study of γ' fibrinogen and incident venous thromboembolism: The Longitudinal Investigation of Thromboembolism Etiology (LITE)

INTRODUCTION

Epidemiological studies generally have not found plasma total fibrinogen to be a risk factor for venous thromboembolism (VTE), but several have reported associations between variants in the fibrinogen gamma gene (FGG) and VTE. A case-control study in whites suggested plasma γ' fibrinogen concentration may be associated inversely with VTE, but this was not replicated in African Americans.

OBJECTIVE

To examine the prospective association between γ' fibrinogen concentrations and occurrence of VTE.

METHODS

We used the Longitudinal Investigation of Thromboembolism Etiology (LITE), involving two pooled population-based cohorts in the United States including 16,234 participants. The cohorts comprised white and African American men and women, aged 50years and older at study onset in the early 1990s. We identified VTEs during follow-up and documented they met standardized diagnostic criteria.

RESULTS

During two decades of follow-up, neither γ' fibrinogen nor total fibrinogen nor their ratio was associated with VTE overall (n=521 VTEs), in subgroups defined by race, or in other subgroups. In both race groups, the minor allele of FGG rs2066865 was associated with lower γ' fibrinogen concentrations, but this allele was not associated with VTE.

CONCLUSIONS

A lower plasma concentration of γ' fibrinogen in healthy adults does not appear to increase VTE risk.

Associations Between Thrombin Generation and the Risk of Cardiovascular Disease in Elderly Patients: Results From the PROSPER Study

BACKGROUND

Hypercoagulability may be an important contributor to the pathophysiology of atherosclerosis and atherothrombosis. As thrombin fulfills a central role in coagulation and links to several cellular mechanisms involved in arterial disease, we hypothesized that thrombin generation is associated with cardiovascular events in elderly patients.

METHODS

We studied the relationship between plasma thrombin generation and incident coronary heart disease (CHD) and stroke in the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER). From this multicenter prospective cohort, 4,932 samples of subjects (70-82 years) with pre-existing vascular disease or risk factors were available for thrombin generation measurements.

RESULTS

Within the 3.2 years of follow-up incident stroke and CHD was observed in 227 and 545 subjects, respectively. Baseline thrombin generation was significantly decreased in subjects with incident stroke compared with subjects without: normalized peak height 71.1±40.8% versus 82.3±44.9%, p = .0002, and normalized endogenous thrombin potential 79.1±23.3% versus 87.0±24.8%, p < .0001 (mean and SDs). Thrombin generation was independently and inversely associated with stroke risk: hazard ratio 0.71 (95%CI: 0.60-0.85), 0.68 (95%CI: 0.58-0.79), for normalized peak height and normalized endogenous thrombin potential, respectively (all p < .001). In subjects with incident CHD, thrombin generation was comparable to subjects without a coronary event. Only an increased normalized peak height was significantly associated with incident CHD (hazard ratio 1.17 [95% CI: 1.06-1.28], p = .002).

CONCLUSIONS

We demonstrate that a delayed and decreased thrombin generation is a strong and independent predictor for stroke in elderly people at increased risk of vascular disease. However, no convincing consistent association could be demonstrated between thrombin generation and incident CHD.

Relationship Between Hematocrit Level and Cardiovascular Risk Factors in a Community-Based Population

BACKGROUND

This study aimed to determine the relationship between hematocrit (HCT) levels and cardiovascular risk factors in a community-based population of middle-aged adults.

METHODS

From April 2011 to February 2012, a total of 1,884 middle-aged adults were selected from a community-based population in China. Blood and urine samples were collected for routine blood and urine tests, and measurement of plasma glucose and lipid levels. Baseline information including traditional cardiovascular risk factors was obtained by standard questionnaire to analyze. We evaluated the distribution of the HCT values for middle-aged adults with or without cardiovascular risk factors. There were 548 males and 1,336 females in this study. The mean age of all subjects was 54.7 ± 6.7 years. There were 1,209 subjects with risk factors and 675 without risk factors.

RESULTS

The HCT levels in subjects with risk factors were higher than those without risk factors (P = 0.005). According to a simplified tool for evaluation of the 10-year risk of ischemic cardiovascular diseases (CVDs) in Chinese populations, all subjects were divided into four groups: the ultralow-risk group (1,367, 72.6%), low-risk group (232, 12.3%), intermediate-risk group (201, 10.7%), and high-risk/ultrahigh-risk group (84, 4.4%). Compared with HCT levels in the ultralow-risk group, significant differences were found in the low-risk, intermediate-risk, and high-risk/ultrahigh-risk groups (all P < 0.05).

CONCLUSION

Our results indicate that elevated HCT levels may be positively associated with cardiovascular risk factors. Thus, the combination of HCT values and cardiovascular risk factors may enable early diagnosis of CVDs.

Prognostic value of low and moderately elevated C-reactive protein in acute coronary syndrome: a 2-year follow-up study

BACKGROUND

The main goal of this study was to improve diagnostic and predictive value of low and moderately elevated C-reactive protein (CRP) in patients with acute coronary syndrome (ACS), related to noninvasive clinical parameters, in order to improve and prolong patient life with low or no additional costs.

MATERIAL/METHODS

A prospective, open clinical study was conducted at the University Hospital Split, Croatia with 112 patients with ACS and low or moderately elevated CRP (<3.0 mg/L). After diagnosing ACS, data on physical activity, alcohol consumption, and functional status were recorded. Anthropometric measurements were made. Blood and urine samples were taken for analyses. Electrocardiographic, ergometric, and echocardiographic testing was performed. A total of 72 parameters were monitored at the time of hospital admission in ACS patients to analyze which ones could predict disease outcome at the end of follow-up in patients with low or moderately elevated CRP. Patients were followed up for 2 years.

RESULTS

The variables that were predictive of major adverse cardiac events (MACE) within 2 years of ACS hospitalization were hemoglobin, fibrinogen, antithrombin III, cholesterol levels, brain natriuretic peptide, and microalbuminuria. ACS patients with CRP<3.0 mg/L had significantly higher risk of developing MACE within 2 years if ≥50% of the 8 key parameters were outside the reference values.

CONCLUSIONS

Major adverse cardiac events can be predicted in patients with acute coronary syndrome whose CRP values are low or moderately elevated.

Cardiovascular benefits of phlebotomy: relationship to changes in hemorheological variables

Renewed interest in the age-old concept of “bloodletting”, a therapeutic approach practiced until as recently as the 19th century, has been stimulated by the knowledge that blood loss, such as following regular donation, is associated with significant reductions in key hemorheological variables, including whole blood viscosity (WBV), plasma viscosity, hematocrit and fibrinogen. An elevated WBV appears to be both a strong predictor of cardiovascular disease and an important factor in the development of atherosclerosis. Elevated WBV through wall shear stress is the most direct physiological parameter that influences the rupture and erosion of vulnerable plaques. In addition to WBV reduction, phlebotomy may reduce an individual’s cardiovascular risk through reductions in excessive iron, oxidative stress and inflammation. Reflecting these findings, blood donation in males has shown significant drops in the incidence of cardiovascular events, as well as in procedures such as percutaneous transluminal coronary angioplasty and coronary artery bypass grafting. Collectively, the available data on the benefits of therapeutic phlebotomy point to the importance of monitoring WBV as part of a cardiovascular risk factor, along with other risk-modifying measures, whenever an increased cardiovascular risk is detected. The development of a scanning capillary tube viscometer allows the measurement of WBV in a clinical setting, which can prove to be valuable in providing an early warning sign of an increased risk of cardiovascular disease.

Thrombin generation in the Glasgow Myocardial Infarction Study

Background

Thrombin is a key protease in coagulation also implicated in complex pathology including atherosclerosis. To address the role of thrombin in relation to myocardial infarction (MI) we explored thrombin generation analysis in plasma from patients and controls that had participated in the Glasgow MI Study (GLAMIS).

Methods

Thrombin generation at 1 and 2 pM TF and with and without thrombomodulin (TM) was performed on plasmas from 356 subjects (171 cases, 185 age and sex matched controls) from GLAMIS collected between 3 and 9 months after the MI event.

Results

Although thrombin generation was slightly delayed in cases (lag time increased from 3.3 to 3.6 min) at the highest trigger, the overall potential to generate thrombin was increased by 7% for the ETP and by 15% for the peak height (both at the 1 pM TF trigger) in cases. Addition of TM did not reveal differences. Furthermore, an increased thrombin generation was associated with MI [normalized ETP: adjusted OR for the highest percentile = 2.4 (95% CI 1.3–4.5) and normalized peak height: adjusted OR = 2.6 (1.3–5.0)] at the lowest trigger; normalized ETP and peak height being 2.1 (1.1–3.8) and 2.0 (1.0–4.1) at the higher 2 pM trigger.

Conclusion

In GLAMIS, patients with a previous MI had an increased thrombin generation compared to controls. The absence of a clear difference in TM reduction suggests an unaltered anticoagulant activity in these patients. Further research is needed in order to unravel the underlying mechanisms of enhanced thrombin generation after MI.

A genome-wide association study for venous thromboembolism: the extended cohorts for heart and aging research in genomic epidemiology (CHARGE) consortium

Venous thromboembolism (VTE) is a common, heritable disease resulting in high rates of hospitalization and mortality. Yet few associations between VTE and genetic variants, all in the coagulation pathway, have been established. To identify additional genetic determinants of VTE, we conducted a two-stage genome-wide association study (GWAS) among individuals of European ancestry in the extended cohorts for heart and aging research in genomic epidemiology (CHARGE) VTE consortium. The discovery GWAS comprised 1,618 incident VTE cases out of 44,499 participants from six community-based studies. Genotypes for genome-wide single-nucleotide polymorphisms (SNPs) were imputed to approximately 2.5 million SNPs in HapMap and association with VTE assessed using study-design appropriate regression methods. Meta-analysis of these results identified two known loci, in F5 and ABO. Top 1,047 tag SNPs (P ≤ 0.0016) from the discovery GWAS were tested for association in an additional 3,231 cases and 3,536 controls from three case-control studies. In the combined data from these two stages, additional genome-wide significant associations were observed on 4q35 at F11 (top SNP rs4253399, intronic to F11) and on 4q28 at FGG (rs6536024, 9.7 kb from FGG; P < 5.0 × 10(-13) for both). The associations at the FGG locus were not completely explained by previously reported variants. Loci at or near SUSD1 and OTUD7A showed borderline yet novel associations (P < 5.0 × 10(-6) ) and constitute new candidate genes. In conclusion, this large GWAS replicated key genetic associations in F5 and ABO, and confirmed the importance of F11 and FGG loci for VTE. Future studies are warranted to better characterize the associations with F11 and FGG and to replicate the new candidate associations.

Hemostatic factors and risk of coronary heart disease in general populations: new prospective study and updated meta-analyses

BACKGROUND

Activation of blood coagulation and fibrinolysis may be associated with increased risk of coronary heart disease. We aimed to assess associations of circulating tissue plasminogen activator (t-PA) antigen, D-dimer and von Willebrand factor (VWF) with coronary heart disease risk.

DESIGN

Prospective case-control study, systematic review and meta-analyses.

METHODS

Measurements were made in 1925 people who had a first-ever nonfatal myocardial infarction or died of coronary heart disease during follow-up (median 19.4 years) and in 3616 controls nested within the prospective population-based Reykjavik Study.

RESULTS

Age and sex-adjusted odds ratios for coronary heart disease per 1 standard deviation higher baseline level were 1.25 (1.18, 1.33) for t-PA antigen, 1.01 (0.95, 1.07) for D-dimer and 1.11 (1.05, 1.18) for VWF. After additional adjustment for conventional cardiovascular risk factors, corresponding odds ratios were 1.07 (0.99, 1.14) for t-PA antigen, 1.06 (1.00, 1.13) for D-dimer and 1.08 (1.02, 1.15) for VWF. When combined with the results from previous prospective studies in a random-effects meta-analysis, overall adjusted odds ratios were 1.13 (1.06, 1.21) for t-PA antigen (13 studies, 5494 cases), 1.23 (1.16, 1.32) with D-dimer (18 studies, 6799 cases) and 1.16 (1.10, 1.22) with VWF (15 studies, 6556 cases).

CONCLUSIONS

Concentrations of t-PA antigen, D-dimer and VWF may be more modestly associated with first-ever CHD events than previously reported. More detailed analysis is required to clarify whether these markers are causal risk factors or simply correlates of coronary heart disease.

A gene-centric analysis of activated partial thromboplastin time and activated protein C resistance using the HumanCVD focused genotyping array

Activated partial thromboplastin time (aPTT) is an important routine measure of intrinsic blood coagulation. Addition of activated protein C (APC) to the aPTT test to produce a ratio, provides one measure of APC resistance. The associations of some genetic mutations (eg, factor V Leiden) with these measures are established, but associations of other genetic variations remain to be established. The objective of this work was to test for association between genetic variants and blood coagulation using a high-density genotyping array. Genetic association with aPTT and APC resistance was analysed using a focused genotyping array that tests approximately 50 000 single-nucleotide polymorphisms (SNPs) in nearly 2000 cardiovascular candidate genes, including coagulation pathway genes. Analyses were conducted on 2544 European origin women from the British Women's Heart and Health Study. We confirm associations with aPTT at the coagulation factor XII (F12)/G protein-coupled receptor kinase 6 (GRK6) and kininogen 1 (KNG1)/histidine-rich glycoprotein (HRG) loci, and identify novel SNPs at the ABO locus and novel locus kallikrein B (KLKB1)/F11. In addition, we confirm association between APC resistance and factor V Leiden mutation, and identify novel SNP associations with APC resistance in the HRG and F5/solute carrier family 19 member 2 (SLC19A2) regions. In conclusion, variation at several genetic loci influences intrinsic blood coagulation as measured by both aPTT and APC resistance.

Prospective study of seasonal patterns in hemostatic factors in older men and their relation to excess winter coronary heart disease deaths

BACKGROUND

In England and Wales, approximately 20% extra deaths from coronary heart disease (CHD) occur between December and March, among older people. Circulating concentrations of tissue plasminogen activator (t-PA), von Willebrand factor (VWF) and fibrin D-dimer are associated with arterial disease, and tend to peak in winter. The potential contributions of these hemostatic activation measures to excess winter mortality are unknown.

OBJECTIVES

To estimate contributions of hemostatic factors to excess winter mortality.

METHODS

Seasonal patterns in t-PA, VWF and D-dimer were investigated in 4088 men aged 60-79 years from 24 British towns. Data on established coronary risk factors were collected by questionnaire, physical examination and blood sampling. The adjusted mean increase in hemostatic markers during winter months, after adjustment for a range of coronary risk factors, was combined with associations of each marker with CHD mortality obtained from 9 years' follow-up of participants, to predict degree of excess CHD winter mortality. Associations of hemostatic markers with CHD incidence from large meta-analyses were also used.

RESULTS

All three markers showed peaks in winter; the adjusted mean increases during winter months were 0.21, 0.15 and 0.12 standard deviations for t-PA, VWF and log(D-dimer), respectively. Predicted excess hazard ratios for winter CHD mortality were 3.0%, 2.4% and 3.1%, respectively, in combination, representing an 8.6% excess. This increased to 14% when applying meta-analysis estimates.

CONCLUSIONS

Seasonal patterns in three hemostatic markers predict at least 8.6% excess CHD mortality in winter in Great Britain, potentially accounting for over half the excess observed in recent years.

Can haemostatic factors predict atherothrombosis?

Thrombosis is "haemostasis in the wrong place", and there is increasing evidence that haemostatic factors are associated with increased risk of atherothrombotic events. Increasing plasma levels of fibrinogen are associated with increased risks of coronary heart disease, stroke and peripheral arterial disease, and with vascular and nonvascular mortality. However, as with other markers of haemostasis (and of inflammation), their additional predictive value to conventional risk factors is small. Ongoing studies of activation markers of coagulation (e.g. fibrin D-dimer), endothelium (e.g. von Willebrand factor, tissue plasminogen activator antigen) and platelets (mean platelet volume) may provide additional predictive value for atherothrombotic events. However, at present there is no sufficient evidence base for their routine measurement in prediction.

A multicentric prospective study in usual care: D-dimer and cardiovascular events in patients with atrial fibrillation

AIM

Atrial fibrillation (AF), the most frequent arrhythmia, is a major independent cardiovascular (CV) risk factor, especially in elderly patients. The interest of Ddimer (DD) measurement for predicting CV risk has been suggested in some subgroups of patients with AF but little is known about the negative prognostic value of DD measurement. The primary aim was to assess whether DD measurement and monitoring could predict the occurrence of subsequent CV events, defined as MI, stroke or transient ischemic attack and arterial embolic events.

METHODS AND RESULTS

It was a prospective observational study including patients with AF. Overall 425 patients (mean age 77years) were included and followed-up every 4months for a 16-months-mean duration. During this period, 26 patients experienced an endpoint of combined CV events. Patients with DD lower than 334ng/ml had a very low risk of suffering of CV events (1.7%). Patients who will suffer from a CV event had a higher DD value, just before the occurrence of the CV event, while patients without CV event kept stable levels.

CONCLUSION

We identified a DD threshold defining at any time patients at low risk of CV event. In addition, patients with higher DD levels are at higher risk of CV events, even if they are receiving oral anticoagulants. Otherwise, DD measurement is relevant in elderly patients. DD measurement and monitoring are useful to assess the risk of CV events in usual care. The implications of DD measurement on the choice and the intensity of the antithrombotic treatment remain to be determined.

D-dimer testing in laboratory practice

BACKGROUND

D-dimer is a reliable and sensitive index of fibrin deposition and stabilization. As such, its presence in plasma should be indicative of thrombus formation. There are many conditions unrelated to thrombosis in which D-dimer concentrations are high, however, making its positive predictive value rather poor.

CONTENT

Notwithstanding these limitations, D-dimer can be regarded as a most valuable laboratory tool to diagnose and manage a vast array of thrombosis-related clinical conditions, including (a) diagnosis of venous thromboembolism (VTE), (b) identification of individuals at increased risk of first thrombotic event (both arterial and venous), (c) identification of individuals at increased risk of recurrent VTE, (d) establishment of the optimal duration of secondary prophylaxis after a first episode of VTE, (e) pregnancy monitoring, and (f) diagnosis/monitoring of disseminated intravascular coagulation (DIC). This article is aimed at reviewing the merits and pitfalls of these applications.

SUMMARY

From my analysis of the literature, I draw the following conclusions. (a) D-dimer, as measured by a sensitive test, can be safely used to exclude VTE in symptomatic outpatients, provided that it is used in combination with the pretest clinical probability. (b) High concentrations of D-dimer are associated with an increased risk of recurrent VTE. (c) Patients who present with D-dimer above cutoff after stopping the regular course of oral anticoagulation benefit from extended prophylaxis. (d) Finally, D-dimer can be used as a fibrin-related degradation marker for the diagnosis/management of patients with DIC.

Incident venous thromboembolic events in the Prospective Study of Pravastatin in the Elderly at Risk (PROSPER)

Background

Venous thromboembolic events (VTE), including deep venous thrombosis and pulmonary embolism, are common in older age. It has been suggested that statins might reduce the risk of VTE however positive results from studies of middle aged subjects may not be generalisable to elderly people. We aimed to determine the effect of pravastatin on incident VTE in older people; we also studied the impact of clinical and plasma risk variables.

Methods

This study was an analysis of incident VTE using data from the Prospective Study of Pravastatin in the Elderly at Risk (PROSPER), a randomized, double-blind, placebo-controlled trial of pravastatin in men and women aged 70-82. Mean follow-up was 3.2 years. Risk for VTE was examined in non-warfarin treated pravastatin (n = 2834) and placebo (n = 2865) patients using a Cox's proportional hazard model, and the impact of other risk factors assessed in a multivariate forward stepwise regression analysis. Baseline clinical characteristics, blood biochemistry and hematology variables, plasma levels of lipids and lipoproteins, and plasma markers of inflammation and adiposity were compared. Plasma markers of thrombosis and hemostasis were assessed in a nested case (n = 48) control (n = 93) study where the cohort was those participants, not on warfarin, for whom data were available.

Results

There were 28 definite cases (1.0%) of incident VTE in the pravastatin group recipients and 20 cases (0.70%) in placebo recipients. Pravastatin did not reduce VTE in PROSPER compared to placebo [unadjusted hazard ratio (95% confidence interval) 1.42 (0.80, 2.52) p = 0.23]. Higher body mass index (BMI) [1.09 (1.02, 1.15) p = 0.0075], country [Scotland vs Netherlands 4.26 (1.00, 18.21) p = 0.050 and Ireland vs Netherlands 6.16 (1.46, 26.00) p = 0.013], lower systolic blood pressure [1.35 (1.03, 1.75) p = 0.027] and lower baseline Mini Mental State Examination (MMSE) score [1.19 (1.01, 1.41) p = 0.034] were associated with an increased risk of VTE, however only BMI, country and systolic blood pressure remained significant on multivariate analysis. In a nested case control study of definite VTE, plasma Factor VIII levels were associated with VTE [1.52 (1.01, 2.28), p = 0.044]. However no other measure of thrombosis and haemostasis was associated with increased risk of VTE.

Conclusions

Pravastatin does not prevent VTE in elderly people at risk of vascular disease. Blood markers of haemostasis and inflammation are not strongly predictive of VTE in older age however BMI, country and lower systolic blood pressure are independently associated with VTE risk.

Trial Registration

Not applicable when study undertaken.

Cognitive function, dementia and type 2 diabetes mellitus in the elderly

Increasing numbers of people are developing type 2 diabetes mellitus, but interventions to prevent and treat the classic microvascular and macrovascular complications have improved, so that people are living longer with the condition. This trend means that novel complications of type 2 diabetes mellitus, which are not targeted by current management strategies, could start to emerge. Cognitive impairment and dementia could come into this category. Type 2 diabetes mellitus is associated with a 1.5-2.5-fold increased risk of dementia. The etiology of dementia and cognitive impairment in people with type 2 diabetes mellitus is probably multifactorial. Chronic hyperglycemia is implicated, perhaps by promoting the development of cerebral microvascular disease. Data suggest that the brains of older people with type 2 diabetes mellitus might be vulnerable to the effects of recurrent, severe hypoglycemia. Other possible moderators of cognitive function include inflammatory mediators, rheological factors and dysregulation of the hypothalamic-pituitary-adrenal axis. Cognitive function should now be included as a standard end point in randomized trials of therapeutic interventions in patients with type 2 diabetes mellitus.

Blood rheology and renal transplantation: an intriguing relationship for assessing cardiovascular risk

Renal transplant recipients (RTRs) are at increased risk of cardiovascular complications. An altered hemorheological profile may determine both cardiovascular complications and progression of renal failure in RTRs. We performed this study to evaluate the rheologic status in 239 RTRs at least 12 months after transplantation with stable and normal renal function compared with 90 control subjects. In RTRs, a significantly higher hematocrit-adjusted, but not native, whole blood viscosity was found (P < .0001). Moreover, plasma viscosity and red blood cell deformability were significantly higher in patients than in control subjects (P < .0001), whereas no difference in erythrocyte aggregation between patients and control subjects was observed (P = .5). Fibrinogen, but not hematocrit, significantly increased in RTRs (P = .001). This preliminary study provides evidence of an altered hemorheologic profile in RTRs.

Prothrombin fragments in cardiovascular disease

Prothrombin fragment 1+2 (F1+2), which comes from in vivo cleavage of prothrombin by factor Xa, is considered to be useful for diagnosis of thrombosis. Recognition of the central role of thrombosis in the pathogenesis ofcardiovascular disease has prompted growing interest in the association o F1+2 with cardiovascular clinical syndromes. Increased F1+2 levels have reported in venous thromboembolism, inflammation, cancer, sepsis, acute coronary syndromes, stroke, peripheral arterial disease, atrial fibrillation and during the postoperative period. However, a clear relationship with the appearance of thrombosis has not always been consistently demonstrated. Besides its potential prognostic and diagnostic value, it could also be usefu in assessing the impact of various therapies. However, it should be kept in mind that measurement of hemostasis activation markers has several important biological and methodological disadvantages. Activation markers reflect the presence of thrombosis in any vascular bed, so they are not specific. Furthermore, elevations occur not only in the presence of overt thrombosis but also during the hypercoagulable state. The cutoff level to be used for the definition of elevations is still largely unknown due to the use of different analytical methods, none of which have been standardized until know. Finally, the prognostic value of F1+2 and other markers of coagulation activation remains to be fully defined in future studies.

A clinical cardiology perspective of thrombophilias

Thrombophilias, an inherited and/or acquired predisposition to vascular thrombosis beyond hemostatic needs are common in cardiovascular medicine and include systemic disorders such as coronary atherosclerosis, atrial fibrillation, exogenous obesity, metabolic syndrome, collagen vascular disease, human immunodeficiency virus, blood replacement therapy and several commonly used medications. A contemporary approach to patients with suspected thrombophilias, in addition to a very selective investigation for gain-of-function and loss-of-function gene mutations affecting thromboresistance, must consider prevalent diseases and management decisions encountered regularly by cardiologists in clinical practice. An appropriate recognition of common disease states as thrombophilias will also stimulate platforms for much needed scientific investigation.

Blood rheology and cognition in the Edinburgh Type 2 Diabetes Study

BACKGROUND

the association between the rheological factors haematocrit and plasma viscosity and cognitive ability has not been extensively studied. It is possible that blood viscosity affects cerebral blood flow and cognitive function. This study tested the contemporaneous associations between these two markers of rheology and cognitive ability and estimated lifetime cognitive change in an elderly population with type 2 diabetes.

METHODS

a cross-sectional cohort of 1,066 men and women with type 2 diabetes (Edinburgh Type 2 Diabetes Study) was used for the analysis. Plasma viscosity and haematocrit were measured in venous blood samples at baseline. Contemporaneously, a battery of seven cognitive tests was administered to all participants. These data were used to derive a general intelligence factor, g. A vocabulary-based test was also administered as an estimate of prior intelligence, and adjustment for scores on this test was used to estimate lifetime cognitive decline.

RESULTS

increased plasma viscosity was associated with poorer age- and sex-adjusted scores on the cognitive domains of processing speed, mental flexibility and general intelligence, g, with standardised regression coefficients -0.092 (P < 0.01), -0.077 (P < 0.05) and -0.093 (P < 0.01), respectively. After adjusting for vocabulary, education level, cardiovascular dysfunction, duration of diabetes and glycaemic control, the associations remained significant for the measure of processing speed and g, with standardised regression coefficients -0.059 (P < 0.05) and -0.051 (P < 0.05). Increased haematocrit was significantly associated with better age- and sex-adjusted cognitive scores on the majority of the tests and with g. However, significant associations were not retained after adjustments for additional covariates.

CONCLUSIONS

increased plasma viscosity is associated with decreased cognitive ability and increased estimated lifetime cognitive decline. The relationship between haematocrit and cognitive ability requires further study.

Coagulation factors II, V, IX, X, XI, and XII, plasminogen, and alpha-2 antiplasmin and risk of coronary heart disease

AIM

To examine whether plasma levels of coagulation factors II, V, IX, X, XI, and XII, plasminogen, and alpha-2 antiplasmin are associated with coronary heart disease (CHD) in a prospective case-cohort study.

METHODS

This case-cohort sample consisted of 368 African-Americans or whites with incident CHD that occurred between 1990-92 and 1998, from the Atherosclerosis Risk in Communities (ARIC) study, and a cohort random sample of n=412. Hemostatic factors were measured in the case-cohort sample using plasma stored at -70 degrees C since 1990-92.

RESULTS

After adjustments for age, sex and race, coagulation factors IX and XI, and alpha-2 antiplasmin were associated positively with risk of CHD: The hazard ratio [95% confidence interval] for the highest vs lowest quartiles was 1.52 [1.01-2.27] for factor IX; 2.26 [1.47-3.48] for factor XI; and 1.64 [1.05-2.57] for alpha-2 antiplasmin. However, as these hemostatic factors were correlated with classical risk factors, their association with CHD was attenuated and no longer statistically significant after multivariable adjustments. No association was observed between CHD and factor II, V, X, or XII, or plasminogen.

CONCLUSIONS

Positive associations of factors IX and XI, and alpha-2 antiplasmin with incident CHD were not strong and accounted for by classical coronary risk factors.

Low protein C and incidence of ischemic stroke and coronary heart disease: the Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND

Protein C is an important plasma natural anticoagulant. Although protein C deficiency increases risk of venous thrombosis, it remains uncertain whether low protein C increases risk of atherothrombosis.

OBJECTIVE

To examine whether low protein C may be a risk factor for ischemic stroke or coronary events in a prospective population-based study.

PATIENTS/METHODS

The Atherosclerosis Risk in Communities Study assessed protein C antigen by ELISA at baseline in 1987-89 and followed participants (n = 13 879) for incident ischemic stroke or coronary events through 2005.

RESULTS

Over a median of 16.9 years of follow-up, 613 ischemic strokes and 1257 coronary heart disease events occurred. Protein C was inversely associated with incidence of ischemic stroke. Adjusted for multiple risk factors, the rate ratios (95% CIs) from highest to lowest quintiles were 1.0, 1.16 (0.90-1.50), 1.22 (0.94-1.58), 1.18 (0.90-1.55) and 1.52 (1.17-1.98). This inverse association was stronger for non-lacunar and cardioembolic stroke than for lacunar stroke. In contrast, there was a positive association between protein C and coronary heart disease in incompletely adjusted models, but no association after adjustment for plasma lipids.

CONCLUSIONS

In this cohort study, low protein C was a risk factor for incident ischemic stroke but not coronary heart disease. Levels of protein C associated with stroke risk were not restricted to the traditional 'deficient' range for protein C (< 0.5 percentile), suggesting that other etiologies for a lower protein C, or genetic variants associated with more subtle changes in protein C, are playing a role in disease pathogenesis.

Factor IX and deep vein thrombosis

Elevated levels of several coagulation factors have been found to be associated with an increased risk of thrombosis. In this perspective article, Dr. Lowe examines the implications of the report by Bezemer and coworkers in this issue for our understanding of the mechanisms involved and how they should direct future research.

[European Guidelines on Cardiovascular Disease Prevention in Clinical Practice. CEIPC 2008 Spanish Adaptation]

The present CEIPC Spanish adaptation of the European Guidelines on Cardiovascular Disease Prevention in Clinical Practice 2008. This guide recommends the SCORE model for risk evaluation. The aim is to prevent premature mortality and morbidity due to CVD by means of dealing with its related risk factors in clinical practice. The guide focuses on primary prevention and emphasizes the role of the nurses and primary care doctors in promoting a healthy life style, based on increasing physical activity, changing dietary habits, and not smoking. The therapeutic goal is to achieve a Blood Pressure<140/90mmHg, but in patients with diabetes, chronic kidney disease, or definite CVD, the objective is<130/80mmHg. Serum cholesterol should be<200mg/dl and cLDL<130mg/dl, although in patients with CVD or diabetes, the objective is<100mg/dl (80mg/dl if feasible in very high-risk patients). Patients with type 2 diabetes and those with metabolic syndrome must lose weight and increase their physical activity, and drugs must be administered whenever applicable, with the objective guided by body mass index and waist circumference. In diabetic type 2 patients, the objective is glycated haemoglobin<7%. Allowing people to know the guides and developing implementation programs, identifying barriers and seeking solutions for them, are priorities for the CEIPC in order to put the recommendations into practice.

Associations of factor VIIIc, D-dimer, and plasmin-antiplasmin with incident cardiovascular disease and all-cause mortality

To examine the associations of three understudied hemostatic factors--D-dimer, factor VIII(c), and plasmin-antiplasmin (PAP) complex--with incident cardiovascular disease (CVD) and all cause mortality in the Multiethnic Study of Atherosclerosis cohort. Hemostatic factors were measured at baseline in 45-84-year-old patients (n = 6,391) who were free of clinically recognized CVD. Over 4.6 years of follow-up, we identified 307 CVD events, 207 hard coronary heart disease events, and 210 deaths. D-dimer, factor VIII(c), and PAP were not associated with CVD incidence after adjustment for other risk factors. In contrast, each factor was associated positively with total mortality, and D-dimer and factor VIII(c) were associated positively with cancer mortality. When modeled as ordinal variables and adjusted for risk factors, total mortality was greater by 33% (95% CI 15-54) for each quartile increment of D-dimer, 26% (11-44) for factor VIIIc, and 20% (4-38) for PAP. This prospective cohort study did not find D-dimer, factor VIII(c), or PAP to be risk factors for CVD. Instead, elevated levels of these three hemostatic factors were associated independently with increased risk of death. Elevated D-dimer and factor VIII(c) were associated with increased cancer death.

Platelet turnover, coagulation factors, and soluble markers of platelet and endothelial activation in essential thrombocythemia: relationship with thrombosis occurrence and JAK2 V617F allele burden

Patients with essential thrombocythemia (ET) have an increased frequency of thrombosis, but the relationship of both thrombosis and JAK2 V617F allele burden with platelet turnover, acquired activated protein C resistance (aAPCR), and levels of coagulation factors and soluble markers of platelet, and endothelial activation is not well known. In 53 ET patients (26 with a history of thrombosis), reticulated platelets (RP) percentage, aAPCR, platelet tissue factor (TF) expression, and plasma levels of TF, coagulation factors, soluble P-selectin (sP-selectin), soluble CD40 ligand (sCD40L), von Willebrand factor antigen (VWF:Ag), soluble thrombomodulin (sTM), D-dimer and prothrombin fragment 1 + 2 were compared with those in matched healthy individuals and correlated with thrombosis occurrence and JAK2 mutational load. ET patients with thrombosis had significantly higher values for RP percentage, aAPCR, and levels of factors V and VIII, VWF:Ag, sP-selectin, and sCD40L than patients without thrombosis and controls. At multivariate study, RP percentage, factor V levels, and aAPCR were independently associated with an increased risk of thrombosis. Patients with JAK2 mutation had significantly lower levels of free protein S (PS) and higher levels of TF, sP-selectin, sCD40L, VWF:Ag, and sTM than those with wild-type allele. A mutant allele dosage effect (>or= 12%) was observed for TF, sP-selectin, sCD40L, VWF:Ag, and PS levels. These results support a role for platelet turnover, factor V, and aAPCR in the thrombosis of ET as well as the association between JAK2 V617F allele burden and either decreased free PS or increased TF and soluble markers of platelet and endothelial activation.

Cardiovascular risk assessment in prediabetes: A hypothesis

There are screening programs for future risk of cardiovascular disease (CVD) complications in diabetes, but not in subclinical diabetes. There is little or no risk and no differences between genders when a man or woman at age below 50 years presents blood pressure below 140/90 mmHg and total cholesterol/HDL less down 7.0. In the current screening programs, a hypothetical apparently non-diabetic and non-smoking person aged 49 years old; who present blood pressure 140/90 mmHg, fasting blood sugar 5.8 mmol/L and total cholesterol/HDL 6.5 has no risk of future CVD and does not require any intervention. However, by counting numbers, the person has two risk factors, hyperglycaemia and hyperlipidaemia. Furthermore, considering smoking as a factor and the propensity for hyperglycaemia-induced oxidative stress being a smoker-like effect of hyperglycaemia toxicity, the person actually has three risk factors, which qualifies the person for intervention. The issue is that a prediabetes sufferer is treated like a healthy person in the current screening programs. The problem here is that risk of CVD in prediabetes is inadequately assessed. We present a hypothesis that employs a combination of blood glucose level and an index of oxidative damage to improve CVD screening in prediabetes. We propose a longitudinal study to repeat the whole lipid modelling exercise in order to develop a separate model chart for the screening of future CVD in people with diagnosed or undiagnosed prediabetes. The proposal would also serve for people with undiagnosed diabetes.