High Purity Factor IX and Prothrombin Complex Concentrate (PCC): Pharmacokinetics and Evidence that Factor IXa Is the Thrombogenic Trigger in PCC

Recent studies using assays for surrogate markers of thrombogenic-ity in man have demonstrated that activation of the coagulation system occurs following infusion of clinical doses of prothrombin complex concentrates (PCC) but not after the same doses of high-purity factor IX concentrates (HP-FIX) in patients with haemophilia B. Here we have investigated the mechanism of such thrombogenesis by applying assays that detect early-through to late-events in coagulation system activation in a pharmacokinetic cross-over study of 50 IU/kg PCC and a new HP-FIX product in haemophilia B patients. Satisfactory recoveries and half-lives were observed for both concentrates.

HP-FIX caused no increases in thrombin-antithrombin III complex (TAT), prothrombin activation peptide fragment F1+2 (F1+2), factor X activation peptide (FXAP) or factor Vila (FVIIa). In contrast the same dose of factor IX in the form of PCC was followed by significant increases over pre-infusion levels of TAT, F1+2 and FXAP, but not FVIIa. Elevations of FIXAP occurred after both HP-FIX and PCC but did not reach normal levels and were attributed to normalisation of the FIX concentration in those patients whose levels of FIXAP were initially low. We conclude that the thrombogenic trigger associated with PCC infusion occurs at the level of factor X activation. In the absence of any increase in FVIIa, we would attribute this to the likely presence of FIXa in the PCC.

Smoking, Haemostatic Factors and the Severity of Aorto-lliac and Femoro-Popliteal Disease

To determine relationships between haemostatic and rheological factors and severity of peripheral atherosclerosis and differences by site, an angiographic cross-sectional survey was carried out on 192 men and women with intermittent claudication or rest pain. 34 patients were classified as having aorto-iliac disease, 85 femoro-popliteal disease and 73 dual-site disease. Mean levels of haemostatic or rheological factors did not differ significantly between the three site groups. In all 192 patients, disease severity in the femoro-popliteal segments was correlated with plasma nephelometric fibrinogen (r = 0.20, p ≤0.01), von Willebrand factor (r = 0.14, p ≤0.05) and fibrin D-dimer (r = 0.22, p ≤0.001). On multiple regression analyses, fibrinogen was independently associated with disease severity in the femoro-popliteal segments (p ≤0.05), but not in the aorto-iliac segments. Adjustment for packyears or serum thiocyanate had little effect on the association of fibrinogen with severity of disease. An inverse relationship between plasminogen activator inhibitor and disease severity in the femoro-popliteal segments was found only in men (r = -0.24, p ≤0.01). We conclude that elevated fibrinogen and disturbed fibrinolytic activity may be related to the extent of disease within the femoro-popliteal arteries, more so than in the aorto-iliac arteries.

The Effect of Fibrinogen Genotype on Fibrinogen Levels after Strenuous Physical Exercise

We have examined the effect of two f3-fibrinogen gene promoter polymorphisms (-455G>A and -854G>A) on the fibrinogen response to severe exercise in a group of male army recruits undergoing basic training. Fibrinogen was measured pre-training and again serially after severe 48 h final military exercise (FME). Out of 884 subjects, 762 completed training of whom 250 were selected for post-FME study. Fibrinogen levels (g/l) were significantly elevated over baseline levels 2, 48 and 96 h after FME, representing increases of 15.7%, 3.4% and 7.6% (p <0.005; p = 0.05 and p <0.005 respectively), with higher levels in -455A allele carriers than genotype -455GG: 3.17 ± 0.05 vs. 2.94 ± 0.05 (p <0.001), 2.86 ± 0.05 vs. 2.60 ± 0.05 (p <0.0005) and 2.98 ± 0.06 vs. 2.69 ± 0.06 (p <0.0005) at 2, 48 and 96 h respectively. There was no effect of the -854G>A polymorphism on fibrinogen, even after taking into account f3-fibrinogen -455 genotype. Thus the fibrinogen -455G>A polymorphism influences fibrinogen levels following exercise. The effect of genotype might be clinically relevant at times of hyperfibrinogenaemia such as following an acute inflammatory response.

Fibrinogen, Factor VII and PAI-1 Genotypes and the Risk of Coronary and Peripheral Atherosclerosis: Edinburgh Artery Study

There are now many epidemiological studies that have shown a relationship between haemostatic factors and subsequent risk of both coronary and peripheral arterial disease. However, there is less information on the association between genetic variation in these factors and the risks of coronary and peripheral arterial disease. As part of the five-year follow-up of the Edinburgh Artery Study, polymorphisms of the fibrinogen (-455G/A), factor VII (R/Q353) and PAI-1 (HindIII) genes were measured in men and women aged 60-79 years, together with their plasma levels. Using widely accepted criteria, 88 subjects were identified as having peripheral arterial disease (PAD), 195 having coronary artery disease (CAD) and 423 subjects comprised a “healthy” group. The -455AA genotype of the fibrinogen gene was found to be more frequent among those subjects with PAD. This genotype also showed the highest plasma fibrinogen levels in both disease groups and in the healthy group. Using logistic regression, after adjustment for age, sex, smoking and plasma level, the -455AA genotype was associated with over twice the risk of PAD compared with the -455GG genotype, the odds ratio reaching marginal significance (p″0.10). Combining those with genotype -455AA with the heterozygotes in order to increase the power of the study resulted in a more significant multiple-adjusted risk of PAD (p″0.05). These data provide evidence that a polymorphism of the β fibrinogen gene is associated with an increased risk of peripheral atherosclerosis.

A Performance Evaluation of Commercial Fibrinogen Reference Preparations and Assays for Clauss and PT-derived Fibrinogen

The wide availability of fibrinogen estimations based on the prothrombin time (PT-Fg) has caused concern about the variability and clinical utility of fibrinogen assays. In a multi-centre study, we investigated fibrinogen assays using various reagents and analysers. Clauss assays generally gave good agreement, although one reagent gave 15–30% higher values in DIC and thrombolysis. Two commercial reference preparations had much lower potencies than the manufacturers declared, and plasma turbidity influenced parallelism in some Clauss assays. PT-Fg assays gave higher values than Clauss and showed calibrant dependent effects, the degree of disparity correlating with calibrant and test sample turbidity. Analyser and thromboplastin dependent differences were noted. The relationship between Clauss and PT-Fg assays was sigmoid, and the plateau of maximal PT-Fg differed by about 2 g/l between reagents. ELISA and immunonephelometric assays correlated well, but with a high degree of scatter. Antigen levels were higher than Clauss, but slightly lower than PT-Fg assays, which appeared to be influenced by degraded fibrinogen. Clauss assays are generally reproducible between centres, analysers and reagents, but PT-Fg assays are not reliable in clinical settings.

Fibrin D-dimer, Tissue Plasminogen Activator, Plasminogen Activator Inhibitor, and the Risk of Major Ischaemic Heart Disease in the Caerphilly Study

Plasma levels of fibrin D-dimer, tissue plasminogen activator (tPA) and plasminogen activator inhibitor (PAI) have been associated with ischaemic heart disease (IHD). However their associations with incident IHD in samples of the general population are not established. D-dimer antigen, tPA antigen and PAI activity were measured in stored, fasting plasma samples from 1,998 men aged 45-65 examined between 1984 and 1988, during the first re-examination of the Caerphilly Study cohort. These variables were related to major IHD events (myocardial infarction or IHD death) which occurred in 129 men during a follow-up period which averaged 61 months. Mean fibrin D-dimer was higher in men who developed IHD events (90 vs. 71 ng/ml; age-adjusted logarithmic mean difference 0.21; 95% CI 0.11, 0.30; p <0.0001). This association remained after adjusting for baseline IHD and for other risk factors including fibrinogen: the adjusted relative odds of IHD in the highest fifth of D-dimer were 3.5 (95% CI 1.8, 6.9; p = 0.0003). Mean tPA antigen was also higher in men who developed IHD (12.6 vs. 11.6 ng/ml; mean difference 0.9; 95% CI 0.2, 1.7; p = 0.02); however this difference largely disappeared after adjusting for other risk factors. PAI activity was not associated with risk of IHD.

Are Atrial Fibrillation Guidelines Altering Management? A Community Based Study

Background and Aims: We wanted to determine the prevalence of atrial fibrillation (AF) in a community based cross sectional study in greater Glasgow and how current anti thrombotic management compares to published guidelines. Methods: 1466 patients with AF were identified in General Practices in our community and 1008 consented to take part. Their demographic details and medical history were recorded. Results: 1466 patients (mean age 73.4; 55% female) with AF were identified, in our community, giving a prevalence of 1%. 53% of patients were on warfarin therapy. Of those not receiving warfarin, only one third had a putative contra-indication. The proportion of AF patients on warfarin increased with increasing stroke risk, and over the period of the study. Conclusions: Prevalence of AF was in keeping with previous estimates. The proportion of patients with AF receiving warfarin therapy appears to be increasing. In the moderate risk group, there was a tendency to use more warfarin in the younger age groups compared to the elderly. It was in the moderate and low risk groups that there was still evidence of deviation from published guidelines.

Systemic effects of polymethylmethycrylate in total knee replacement: A prospective case-control study

OBJECTIVE

Mortality rates reported by the National Joint Registry for England and Wales (NJR) were higher following cemented total knee replacement (TKR) compared with uncemented procedures. The aim of this study is to examine and compare the effects of cemented and uncemented TKR on the activation of selected markers of inflammation, endothelium, and coagulation, and on the activation of selected cytokines involved in the various aspects of the systemic response following surgery.

METHODS

This was a single centre, prospective, case-control study. Following enrolment, blood samples were taken pre-operatively, and further samples were collected at day one and day seven post-operatively. One patient in the cemented group developed a deep-vein thrombosis confirmed on ultrasonography and was excluded, leaving 19 patients in this cohort (mean age 67.4, (sd 10.62)), and one patient in the uncemented group developed a post-operative wound infection and was excluded, leaving 19 patients (mean age 66.5, (sd 7.82)).

RESULTS

Both groups had a similar response with regards to the levels of C-reactive protein (CRP), interleukin 6 (IL-6) and tumour necrosis factor-alpha (TNFα). CD40 levels rose significantly on the cemented group over day one to day seven compared with that of the uncemented group, which occurred over the first 24 hours. The CD14/42a levels demonstrated a statistically significant increase in the cemented group (p < 0.001 first 24 hours and p = 0.02 between days one and seven).

CONCLUSIONS

The uncemented and cemented groups demonstrated significant changes in the various parameters measured at various time points but apart from CD14/42a levels, there was no significant difference in the serum markers of inflammation, coagulation and endothelial dysfunction following cemented TKR. Cite this article: Bone Joint Res 2014;3:108-16.

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.

Prospective study of circulating soluble CD40 ligand concentrations and the incidence of cardiovascular disease in a nested prospective case-control study of older men and women

BACKGROUND

CD40 ligand(CD40L) is implicated in atherosclerotic plaque formation.

OBJECTIVES

We investigated prospective associations between circulating soluble CD40L and myocardial infraction (MI) or stroke in an older general population cohort, accounting for established and novel cardiovascular risk factors.

METHODS

Baseline serum CD40L (sCD40L) was measured in incident MI (n = 368) and stroke (n = 304) cases and two controls per case, 'nested' in prospective UK studies of 4252 men and 4286 women aged 60-79 years, sampled from general practices in Britain in 1998-2000, with 7-year follow-up for fatal and non-fatal MI and stroke.

RESULTS

sCD40L was higher in smokers and negatively associated with lung function and positively associated with total cholesterol and markers of inflammation, but not with other established cardiovascular disease (CVD) risk factors. Geometric mean sCD40L levels did not differ between MI cases and controls (5.94 ng mL(-1) vs. 5.82 ng mL(-1); P = 0.5) or between stroke cases and controls (5.61 ng mL(-1) vs. 5.28 ng mL(-1), P = 0.1). There was no strong evidence for elevated risk of MI or stroke in multivariable models comparing participants in the top to those in the bottom third of sCD40L. Age-adjusted odds ratios (ORs) were 1.39 [95% confidence interval (CI) 0.98, 1.96] for MI and 1.16 (0.78, 1.73) for stroke. These attenuated to 1.24 (95% CI 0.86, 1.79) and 1.18 (0.78, 1.78), respectively, after adjustment for established and novel CVD risk factors.

CONCLUSIONS

sCD40L is associated with other inflammatory markers but is not itself a strong independent risk marker for either stroke or MI.

Sex differences in the relationship between inflammatory and hemostatic biomarkers and metabolic syndrome: British 1958 Birth Cohort

BACKGROUND

Circulating levels of C-reactive protein (CRP), fibrinogen, fibrin D-dimer, tissue plasminogen activator antigen (t-PA) and von Willebrand factor (VWF) are associated with incident coronary heart disease (CHD). However, their associations with metabolic syndrome and its components in large populations of men and women have not been well defined.

OBJECTIVES

We compare the sex associations of these biomarkers with established CHD risk factors, metabolic syndrome and its components in a large cohort.

PATIENTS AND METHODS

8302 men and women aged 45 years from the British 1958 birth cohort provided a blood sample. Analyses were restricted to 3457 men and 3464 women with complete data on all risk factors and no history of cardiovascular disease. Multiple regression analyses adjusted for smoking, social class, alcohol consumption and variables related to biomarker measurement error.

RESULTS

Adjusted sex differences in levels of all biomarkers (except VWF) varied according to presence/absence of metabolic syndrome, its components and obesity (BMI ≥30 kg m(-) (2)). Associations in women were up to twice as strong for CRP, fibrinogen and t-PA with markers of obesity (body mass index, waist circumference), blood pressure, blood lipids and metabolic syndrome. D-dimer showed weaker associations and less heterogeneity by sex. There was no evidence of sex interaction in associations with VWF.

CONCLUSIONS

Associations between CRP, fibrinogen and t-PA and metabolic syndrome and its components were stronger in women than in men. Understanding the reasons for these differences across sex will be important in understanding the pathophysiology of cardiovascular and metabolic disease in men and women.

Effects of short-term therapy with glibenclamide and repaglinide on incretin hormones and oxidative damage associated with postprandial hyperglycaemia in people with type 2 diabetes mellitus

AIM

To examine the effects of glibenclamide and repaglinide on glucose stimulated insulin release, incretins, oxidative stress and cell adhesion molecules in patients with type 2 diabetes suboptimally treated with metformin.

METHODS

A randomized clinical trial was performed recruiting 27 subjects (HbA(1c) between 7.5 and 10.5%) free from cardiovascular and renal disease. Glucose, insulin, C-peptide, glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic peptide (GIP), total antioxidant status, F(2)-isoprostane, interleukin-6 and cell adhesion molecules were measured during an oral glucose load at baseline and after eight weeks of treatment. The areas under the curve were analysed at 45, 60 and 120 min (AUC(45), AUC(60), AUC(120)).

RESULTS

Significant improvements in glucose were observed with repaglinide (HBA(1c): -1.5%, fasting glucose: -2.8 mmol/L, 2-h glucose: -3.7 mmol/L, AUC(120): -18.9%) and glibenclamide (-1.0%, -2.2 mmol/L, -2.5 mmol/L, -17.5%). Repaglinide was also associated with an increase in the AUC(60) and AUC(120) for insulin (+56%, +61%) and C-peptide (+41%, +36%). GLP-1, GIP, IL-6, ICAM-1 and E-selectin levels did not change in either group. No association was observed between GLP-1, GIP-1 and plasma markers of oxidative stress.

CONCLUSION

Repaglinide is associated with improved postprandial glycaemic control via insulin and C-peptide release. We observed no direct effects of glibenclamide or repaglinide on plasma levels of GLP-1 or GIP. We observed no associations of GLP-1 and GIP with plasma markers of oxidative stress.

Prospective study of circulating soluble CD40 ligand concentrations and the incidence of cardiovascular disease in a nested prospective case-control study of older men and women

BACKGROUND

CD40 ligand(CD40L) is implicated in atherosclerotic plaque formation.

OBJECTIVES

We investigated prospective associations between circulating soluble CD40L and myocardial infraction (MI) or stroke in an older general population cohort, accounting for established and novel cardiovascular risk factors.

METHODS

Baseline serum CD40L (sCD40L) was measured in incident MI (n = 368) and stroke (n = 304) cases and two controls per case, 'nested' in prospective UK studies of 4252 men and 4286 women aged 60-79 years, sampled from general practices in Britain in 1998-2000, with 7-year follow-up for fatal and non-fatal MI and stroke.

RESULTS

sCD40L was higher in smokers and negatively associated with lung function and positively associated with total cholesterol and markers of inflammation, but not with other established cardiovascular disease (CVD) risk factors. Geometric mean sCD40L levels did not differ between MI cases and controls (5.94 ng mL(-1) vs. 5.82 ng mL(-1); P = 0.5) or between stroke cases and controls (5.61 ng mL(-1) vs. 5.28 ng mL(-1), P = 0.1). There was no strong evidence for elevated risk of MI or stroke in multivariable models comparing participants in the top to those in the bottom third of sCD40L. Age-adjusted odds ratios (ORs) were 1.39 [95% confidence interval (CI) 0.98, 1.96] for MI and 1.16 (0.78, 1.73) for stroke. These attenuated to 1.24 (95% CI 0.86, 1.79) and 1.18 (0.78, 1.78), respectively, after adjustment for established and novel CVD risk factors.

CONCLUSIONS

sCD40L is associated with other inflammatory markers but is not itself a strong independent risk marker for either stroke or MI.

The prevalence and analysis of risk factors for age-related macular degeneration: 18-year follow-up data from the Speedwell eye study, United Kingdom

AIMS/PURPOSE

To determine the prevalence of age-related maculopathy (ARM) and age-related macular degeneration (AMD) in men aged 65-83 years living in the Speedwell region of Bristol, United Kingdom and identify modifiable risk factors.

METHODS

A total of 2348 men recruited to the Speedwell prospective cohort study in 1979 were followed up in 1997 with an eye questionnaire and had retinal photographs that were assessed using the International Classification System for ARM.

RESULTS

In all, 934 men (66.8% response rate) attended with a mean of 17.9 years (15.3-20.6 years) follow-up. Early ARM (grades 2-3) was found in 9.2% (95% confidence interval (CI) 7.4%, 11.4%) and late age-related maculopathy (grade 4, AMD) in 0.5% (95% CI 0.2%, 1.2%). The risk of ARM (grades 2-4) was increased with raised C-reactive protein and consumption of lard and solid fats, whereas triglyceride levels were associated with a lower risk. The latter were confirmed in multivariable analyses and in addition, haemodynamic measures also predicted risk (eg mean arterial pressure odds ratio (OR) per z-score 1.37, 95% CI 1.04, 1.79).

CONCLUSIONS

In a representative cohort of men aged 65-83 from Bristol, United Kingdom, many had macular changes that put them at higher risk of developing AMD. Various modifiable exposures were associated with an increased risk ARM/AMD. Opportunities for screening and undertaking secondary prevention interventions need to be explored to prevent progression of the disease and blindness.

Socioeconomic inequalities in coronary heart disease risk in older age: contribution of established and novel coronary risk factors

BACKGROUND

Evidence on socioeconomic inequalities in coronary heart disease (CHD) and their pathways in the elderly is limited. Little is also known about the contributions that novel coronary risk factors (particularly inflammatory/hemostatic markers) make to socioeconomic inequalities in CHD.

OBJECTIVES

To examine the extent of socioeconomic inequalities in CHD in older age, and the contributions (relative and absolute) of established and novel coronary risk factors.

METHODS

A population-based cohort of 3761 British men aged 60-79 years was followed up for 6.5 years for CHD mortality and incidence (fatal and non-fatal). Social class was based on longest-held occupation recorded at 40-59 years.

RESULTS

There was a graded relationship between social class and CHD incidence. The hazard ratio for CHD incidence comparing social class V (unskilled workers) with social class I (professionals) was 2.70 [95% confidence interval (CI) 1.37-5.35; P-value for trend = 0.008]. This was reduced to 2.14 (95% CI 1.06-4.33; P-value for trend = 0.11) after adjustment for behavioral factors (cigarette smoking, physical activity, body mass index, and alcohol consumption), which explained 38% of the relative risk gradient (41% of absolute risk). Additional adjustment for inflammatory markers (C-reactive protein, interleukin-6, and von Willebrand factor) explained 55% of the relative risk gradient (59% of absolute risk). Blood pressure and lipids made little difference to these estimates; results were similar for CHD mortality.

CONCLUSIONS

Socioeconomic inequalities in CHD persist in the elderly and are at least partly explained by behavioral risk factors; novel (inflammatory) coronary risk markers made some further contribution. Reducing inequalities in behavioral factors (especially cigarette smoking) could reduce these social inequalities by at least one-third.

Circulating inflammatory and hemostatic biomarkers are associated with risk of myocardial infarction and coronary death, but not angina pectoris, in older men

AIMS

The extent to which hemostatic and inflammatory biomarkers are related to angina pectoris as compared with myocardial infarction (MI) remains uncertain. We examined the relationship between a wide range of inflammatory and hemostatic biomarkers, including markers of activated coagulation, fibrinolysis and endothelial dysfunction and viscosity, with incident myocardial infarction (MI) or coronary heart disease (CHD) death and incident angina pectoris uncomplicated by MI or CHD death in older men.

METHODS

A prospective study of 3217 men aged 60-79 years with no baseline CHD (angina or MI) and who were not on warfarin, followed up for 7 years during which there were 198 MI/CHD death cases and 220 incident uncomplicated angina cases.

RESULTS

Inflammatory biomarkers [C-reactive protein (CRP), interleukin-6, fibrinogen], plasma viscosity and hemostatic biomarkers [von Willebrand factor (VWF) and fibrin D-dimer] were associated with a significant increased risk of MI/CHD death but not with uncomplicated angina even after adjustment for age and conventional risk factors. Adjustment for CRP attenuated the relationships between VWF, fibrin D-dimer and plasma viscosity with MI/CHD death. Comparisons of differing associations with risk of MI/CHD deaths and uncomplicated angina were significant for the inflammatory markers (P < 0.05) and marginally significant for fibrin D-dimer (P = 0.05). In contrast, established risk factors including blood pressure and high-density lipoprotein (HDL)-cholesterol were associated with both MI/CHD death and uncomplicated angina.

CONCLUSION

Circulating biomarkers of inflammation and hemostasis are associated with incident MI/CHD death but not incident angina uncomplicated by MI or CHD death in older men.

Secondhand smoke (SHS) exposure is associated with circulating markers of inflammation and endothelial function in adult men and women

AIMS

Secondhand smoke (SHS) exposure is associated with elevated CHD risks. Yet the pathways through which this may operate have not been investigated in epidemiologic studies with objective SHS exposure measures and a wide range of CHD risk factors associated with active smoking. Therefore we investigate associations between SHS exposure and CHD risk factors, to clarify how SHS exposure may raise risk of CHD.

METHODS

Cross-sectional population-based study of 5029 men and women aged 59-80 years from primary care practices in Great Britain. Smoking, behavioural and demographic information was reported in questionnaires; nurses made physical measurements and took blood samples for analysis of serum cotinine and markers of inflammation, hemostasis and endothelial dysfunction.

RESULTS

Active cigarette smokers had lower albumin and higher triglycerides, CRP, IL-6, white cell count, fibrinogen, blood viscosity, factor VIII, VWF and t-PA than non-smokers. Among non-smokers, serum cotinine levels were independently positively associated with CRP, fibrinogen, factor VIII, VWF and t-PA and inversely associated with albumin, after adjustment for age, gender, social and behavioural factors. The differences in CRP, fibrinogen and albumin between cotinine < or =0.05 and >0.7 ng/ml were one-third to one half the size of differences between cotinine < or =0.05 ng/ml and current smokers, but were of similar magnitude for VWF and t-PA.

CONCLUSIONS

Endothelial, inflammatory and haemostatic markers related to CHD risk showed independent associations with SHS exposure in the same direction as those for active smoking. Results aid understanding of the associations between SHS exposure and elevated CHD risks.

Associations of C-reactive protein and interleukin-6 with cognitive symptoms of depression: 12-year follow-up of the Whitehall II study

BACKGROUND

A lack of longitudinal studies has made it difficult to establish the direction of associations between circulating concentrations of low-grade chronic inflammatory markers, such as C-reactive protein and interleukin-6, and cognitive symptoms of depression. The present study sought to assess whether C-reactive protein and interleukin-6 predict cognitive symptoms of depression or whether these symptoms predict inflammatory markers.

METHOD

In a prospective occupational cohort study of British white-collar civil servants (the Whitehall II study), serum C-reactive protein, interleukin-6 and cognitive symptoms of depression were measured at baseline in 1991-1993 and at follow-up in 2002-2004, an average follow-up of 11.8 years. Symptoms of depression were measured with four items describing cognitive symptoms of depression from the General Health Questionnaire. The number of participants varied between 3339 and 3070 (mean age 50 years, 30% women) depending on the analysis.

RESULTS

Baseline C-reactive protein (beta=0.046, p=0.004) and interleukin-6 (beta=0.046, p=0.005) predicted cognitive symptoms of depression at follow-up, while baseline symptoms of depression did not predict inflammatory markers at follow-up. After full adjustment for sociodemographic, behavioural and biological risk factors, health conditions, medication use and baseline cognitive systems of depression, baseline C-reactive protein (beta=0.038, p=0.036) and interleukin-6 (beta=0.041, p=0.018) remained predictive of cognitive symptoms of depression at follow-up.

CONCLUSIONS

These findings suggest that inflammation precedes depression at least with regard to the cognitive symptoms of depression.

Serum matrix metalloproteinase-9 and coronary heart disease: a prospective study in middle-aged men

BACKGROUND

Matrix metalloproteinase-9 (MMP-9) has a potential role in arterial plaque rupture, but its relation to risk of coronary heart disease (CHD) is uncertain.

AIM

To determine whether circulating levels of serum MMP-9 are prospectively related to the risk of CHD in the general population.

METHODS

We measured baseline MMP-9 levels in stored serum samples of subjects in a case-control study nested within a prospective study of 5661 men followed up for 16 years for CHD events (465 cases, 1076 controls).

RESULTS

MMP-9 values were associated with cigarette smoking, and with several inflammatory and haemostatic markers, but not with age, body mass index, blood pressure or lipid measurements. Men in the top third of baseline MMP-9 levels had an age-adjusted odds ratio (OR) for CHD of 1.37 (95% CI 1.04-1.82) compared with those in the bottom third. Adjustment for conventional risk factors (smoking in particular) reduced the odds ratio to borderline significance: OR 1.28 (95% CI 0.95-1.74), while additional adjustment for two markers of generalized inflammation, interleukin-6 and C-reactive protein, further attenuated the association: OR 1.13 (0.82-1.56).

CONCLUSION

Serum MMP-9 has a modest association with incident CHD in the general population, which is not independent of cigarette smoking exposure and circulating markers of generalized inflammation. MMP-9 is unlikely to be a clinically useful biomarker of CHD risk, but may still play a role in the pathogenesis of CHD.

Early life growth and hemostatic factors: the Barry Caerphilly Growth study

Associations between early life growth trajectories and a range of adult (aged approximately 25 years) hemostatic factors were assessed in the Barry Caerphilly Growth study (N = 517) in South Wales, 1974-1999. Associations of birth weight, birth length, and weight and height velocities during three periods ("immediate": 0-<5 months, "infant": 5 months-<1 year 9 months, and "childhood": 1 year 9 months-5 years) with adult levels of hemostatic factors were assessed. Birth weight was inversely associated with fibrinogen (beta per 1-unit change in z score = -0.08, 95% confidence interval (CI): -0.15, -0.02). Immediate weight velocity was inversely associated with factor VII (beta = -1.88, 95% CI: -3.84, 0.09), factor VIII (beta = -2.58, 95% CI: -4.07, -0.45), and von Willebrand factor antigen (beta = -4.07, 95% CI: -7.25, -0.89). Birth length was inversely associated with fibrinogen (beta = -0.07, 95% CI: -0.14, -0.01). Evidence was weaker for an inverse association of immediate height velocity with factor VIII (beta = -2.16, 95% CI: -4.62, 0.29) and von Willebrand factor antigen (beta = -2.85, 95% CI: -6.52, 0.81). Childhood height velocity was positively associated with D-dimer (ratio of geometric means = 1.11, 95% CI: 1.01, 1.23). Results support the view that the immediate postnatal period may be particularly important, possibly through impaired liver development and/or infection in early life, in determining cardiovascular disease risk.

Evidence that high von Willebrand factor and low ADAMTS-13 levels independently increase the risk of a non-fatal heart attack

BACKGROUND

A disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS-13) may influence von Willebrand factor (VWF) levels and consequently the risk of myocardial infarction (MI). Moreover, ADAMTS-13 influences hemostatic plug formation in mouse models. We therefore studied their associations in the Glasgow MI Study (GLAMIS).

METHODS AND RESULTS

We measured ADAMTS-13 and VWF antigen levels by ELISAs in stored plasma from a case-control study of 466 MI cases and 484 age- and sex-matched controls from the same north Glasgow population. There was no correlation between ADAMTS-13 and VWF levels in cases or controls. ADAMTS-13 levels correlated positively with serum cholesterol and triglycerides and body mass index, and negatively with high-density lipoprotein-cholesterol. VWF levels correlated with age, fibrinogen and C-reactive protein. In multivariable analyses including risk factors, VWF correlated positively with risk of MI, and ADAMTS-13 correlated negatively with risk of MI. These associations were independent of each other. The association of ADAMTS-13 with risk of MI was observed only in multivariable analysis.

CONCLUSIONS

VWF and ADAMTS-13 levels were not associated in this study, and showed associations with MI risk in opposite directions but of similar strength. The association of ADAMTS-13 with MI is influenced by lipid levels, and consequently requires further investigation.

Fetal corticotrophin-releasing hormone mRNA, but not phosphatidylserine-exposing microparticles, in maternal plasma are associated with factor VII activity in pre-eclampsia

BACKGROUND

Pre-eclampsia is associated with increased placental debris circulating in maternal plasma.

OBJECTIVES

This study related placental debris to maternal markers of coagulation and endothelial activation in pre-eclampsia.

PATIENTS/METHODS

Circulating fetal corticotrophin-releasing hormone (CRH) mRNA and phosphatidylserine (PS)-exposing microparticles were assayed in third trimester plasma from women with pre-eclampsia (n = 32) and controls (n = 32) matched for age, body mass index, parity, and gestational age at sampling. Markers of maternal hemostasis and endothelial function were assessed.

RESULTS

Fetal CRH mRNA levels were higher in pre-eclampsia [mean 0.75 (SD 2.77) CRH/glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA ratio] than in control pregnancies [0.20 (0.74), P = 0.014]. PS-exposing microparticle levels were not different between the groups. Women with pre-eclampsia had higher levels of tissue factor pathway inhibitor (TFPI), prothrombin F(1+2) fragment (F(1+2)), factor XIIa, soluble vascular cell adhesion molecule 1, von Willebrand factor and plasminogen activator inhibitor 1 than controls. Fetal CRH mRNA correlated with TFPI in pre-eclampsia and control groups (r = 0.38, P = 0.031, and r = 0.37, P = 0.039, respectively). Fetal CRH mRNA correlated with FVII activity (r = 0.43, P = 0.017) and PS-exposing microparticles correlated inversely with F(1+2) (r = -0.64, P < 0.001) in pre-eclampsia.

CONCLUSIONS

Placental debris, assessed by fetal CRH mRNA levels in maternal blood, is related to coagulation potential, i.e. FVII activity, but not to markers of coagulation or endothelial activation in pre-eclampsia.

A comparison of the associations between seven hemostatic or inflammatory variables and coronary heart disease

BACKGROUND

While meta-analyses of prospective studies have established that plasma levels of several hemostatic variables are associated with the risk of coronary heart disease (CHD), these have been suggested to be acute-phase reactant proteins. This study examines their associations with inflammatory markers [C-reactive protein (CRP) and interleukin-6 (IL-6)] and the effect of adjustment on their associations with CHD risk.

METHODS AND RESULTS

In a nested case-control study, 247 CHD cases and 473 controls were matched for age and sex from 10 529 men and women in the Fletcher Challenge cohort. Plasma levels of all hemostatic variables except von Willebrand factor (VWF) and lipoprotein (a) [Lp(a)] showed significant associations with CRP and IL-6. Fibrinogen, VWF, tissue plasminogen activator antigen (t-PA), D-dimer, Lp(a), CRP and IL-6 levels were significantly associated with risk of CHD. After adjustment for conventional risk factors, CRP, D-dimer and IL-6 levels were significantly associated with risk of CHD. On further adjustments for the other six hemostatic and inflammatory variables these associations were reduced, but remained significant for D-dimer and IL-6; odds ratios (95% CI), comparing the highest to lowest third, were 3.10 (1.25-7.67) and 2.79 (1.11-6.99), respectively.

CONCLUSION

The associations of plasma levels of some hemostatic variables (fibrinogen, VWF, t-PA and Lp(a); but not fibrin D-dimer) with CHD risk are attenuated when inflammatory markers (CRP and IL-6) as well as conventional risk factors are included in multivariable analyses. D-dimer and IL-6 each have the potential to increase the prediction of CHD, in addition to conventional risk factors.

Inter-relationships of interleukin-6, cardiovascular risk factors and the metabolic syndrome among older men

OBJECTIVES

Interleukin-6 (IL-6) has been implicated in the development of cardiovascular disease. We have examined the relationship between plasma IL-6 and insulin resistance, and metabolic, inflammatory and hemostatic markers.

METHODS

We examined 3490 men aged 60-79 years who were drawn from general practices in 24 British towns. The men were not diabetic and were not taking warfarin.

RESULTS

IL-6 was significantly associated with age, body mass index (BMI), waist circumference (WC), cigarette smoking, low physical activity, social class and alcohol intake (U-shaped). IL-6 showed no association with insulin resistance or its other components (blood glucose, triglycerides, blood pressure) except high-density lipoprotein-cholesterol (inversely), and no association with hematocrit, factor (F) VII or adiponectin after adjustment for age and WC. IL-6 was strongly associated with markers of inflammation (C-reactive protein, fibrinogen, white cell count); plasma viscosity; elevated markers of coagulation (fibrin D-dimer, FVIII, FIX); markers of endothelial dysfunction (von Willebrand factor, tissue plasminogen activator); and to a smaller extent with platelet count, APC ratio and gamma glutamyltransferase. Risk of the metabolic syndrome increased significantly with increasing IL-6 but was attenuated after adjustment for BMI.

CONCLUSION

IL-6 may have a potential role as a mediator between cardiovascular risk factors and several biological mechanisms for cardiovascular disease.

Associations of adiponectin with metabolic and vascular risk parameters in the British Regional Heart Study reveal stronger links to insulin resistance-related than to coronory heart disease risk-related parameters

BACKGROUND AND AIM

Adiponectin is considered by many to be part of the 'common soil' linking type 2 diabetes and coronary heart disease (CHD). We examined the relationship between adiponectin and insulin resistance, metabolic, inflammatory and haemostatic risk factors and hepatic function.

METHODS AND RESULTS

The study was carried out in 3640 non-diabetic men aged 60-79 years drawn from general practices in 24 British towns and who were not on warfarin. Adiponectin was associated with waist circumference (inversely), alcohol intake (positively) and physical activity (nonlinearly); no association was seen with cigarette smoking, prevalent CHD or stroke. After adjustment for these factors, adiponectin was significantly inversely associated with insulin resistance, triglyceride, C-reactive protein (but not interleukin 6), tissue plasminogen activator and alanine aminotransferase and positively associated with high-density lipoprotein cholesterol (HDL-cholesterol) and Factor VIII, factors associated with diabetes. No association was seen with cholesterol, smoking, systolic blood pressure or coagulation factors. Risk of the metabolic syndrome decreased significantly with increasing adiponectin.

CONCLUSION

Adiponectin is inversely associated with factors strongly associated with the development of diabetes. Limited associations with the established major risk factors for CHD suggest adiponectin may be a stronger marker of risk for diabetes than for CHD.

Effects of older age on fibrin D-dimer, C-reactive protein, and other hemostatic and inflammatory variables in men aged 60-79 years

BACKGROUND

Previous studies have suggested that several hemostatic and inflammatory variables, which are risk predictors for arterial or venous thrombosis, increase with age. However, there is a lack of data from large population studies for reliable estimates of reference ranges.

OBJECTIVES

To establish reliable reference ranges of hemostatic and inflammatory variables for 5-year age groups in older men and their implications for pathogenesis and diagnosis.

PATIENTS AND METHODS

A total of 3861 men aged 60-79 years at the 20 years follow-up of the British Regional Heart Study.

RESULTS

Several variables increased with age. The greatest median increases between 60-64 and 75-79 years age groups were observed for fibrin D-dimer (91%) and C-reactive protein (CRP) (57%). Significant median increases were also observed for von Willebrand factor antigen (23%), tissue plasminogen activator antigen (11%), factor VIII (10%), and fibrinogen (8%). In contrast, levels of classical cardiovascular risk factors neither decreased nor increased substantially with age, with the exception of systolic blood pressure (median increase 10%).

CONCLUSIONS

The exponential increases in risk of arterial and venous thrombotic events in men between age 60 and 79 years (when most such events occur) may be related in part to increasing activation of blood coagulation, fibrinolysis, and inflammation; possibly related to the increasing inflammatory burden of both atherosclerotic and non-vascular disease. These increases also have implications for diagnosis of suspected acute venous thromboembolism (D-dimer), and recently proposed screening for prediction of coronary heart disease risk and detection of occult disease (CRP).

Plasma lipid peroxides: relationships to cardiovascular risk factors and prevalent cardiovascular disease

BACKGROUND

The epidemiology of plasma lipid peroxides, which may play a role in atherogenesis, has not been well defined.

AIM

To study the relationships of plasma lipid peroxides to cardiovascular risk factors in a random population sample.

DESIGN

Random, age- and sex-stratified population sample.

METHODS

We studied 739 men and women aged 25-74 years. Lipid peroxides were assayed by the thiobarbituric acid (TBA) assay for malondialdehyde (MDA) in stored plasma samples.

RESULTS

Lipid peroxide levels increased with age. In men, lipid peroxides were significantly associated with smoking habit. Lipid peroxides correlated with non-fasting serum triglycerides (r = 0.33; p < 0.0001) in both sexes. Weaker associations were observed for cholesterol, high-density lipoprotein cholesterol (inversely), body mass index, fibrinogen and white cell count; as well as an inverse association with serum vitamin C in men.

DISCUSSION

These findings clarify the relationships of plasma lipid peroxides to cardiovascular risk factors; and are consistent with the hypothesis that lipid peroxidation may be one mechanism through which several risk factors may promote cardiovascular disease.

A randomized comparison of the effects of aspirin and clopidogrel on thrombotic risk factors and C-reactive protein following myocardial infarction: the CADET trial

A randomized, double-blind multicenter trial-the Clopidogrel and Aspirin: Determination of the Effects on Thrombogenicity (CADET) trial-was carried out to compare the effects of clopidogrel vs. aspirin on thrombotic variables and C-reactive protein (CRP), over a 6-month period of treatment, in patients with an acute myocardial infarction within the previous 3-7 days, who were not scheduled for major surgery including coronary artery bypass grafting. Patients (n = 184) were randomly allocated to aspirin (75 mg day(-1)) or clopidogrel (75 mg day(-1)). Blood samples were taken at baseline and then at clinic visits at 1, 3 and 6 months. By 1 month, clottable and immunonephelometric fibrinogen, D-dimer, von Willebrand factor, factor VIII and CRP were significantly (P < 0.05) reduced from baseline values in both treatment groups; as well as tissue plasminogen activator antigen in the aspirin group only. At 6 months, there were no differences between treatment groups (P > 0.05) for any of the variables, whether or not potential confounding variables were adjusted for. Similarly, there were no differences between treatments in the difference between baseline and final values for any of the variables. Aspirin and clopidogrel were thus found to have similar effects on thrombotic variables and CRP in this patient population.

Dementia in subjects with atrial fibrillation: hemostatic function and the role of anticoagulation

BACKGROUND

Atrial fibrillation (AF) is associated with cognitive impairment and dementia, perhaps through encouraging a prothrombotic state and cardioembolism.

OBJECTIVES

We wished to test the hypotheses that hemostatic function is altered in subjects with AF who develop dementia, and that long-term warfarin anticoagulation is protective against this complication.

PATIENTS AND METHODS

Recruitment was from an observational cohort study of AF. Baseline assessment included measurement of plasma fibrinogen, fibrin D-dimer, prothrombin fragment 1+2 (F1+2), thrombin-antithrombin complexes (TAT), von Willebrand factor and tissue plasminogen activator. We assessed cognitive function after 3 years' follow-up using the 13-item modified Telephone Interview for Cognitive Status (TICSm) and the short form of the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE).

RESULTS

Of the 218 subjects assessed, 145 (66%) were prescribed warfarin. Forty-nine (22%) met TICSm/IQCODE criteria for dementia. D-dimer, F1+2 and TAT levels were higher in AF subjects with dementia compared with those without (medians 81 vs. 60 ng mL(-1), P = 0.008; 0.76 vs. 0.49 nmol L(-1), P = 0.006; and 1.78 vs. 1.44 microg L(-1), P = 0.003, respectively). These associations became of borderline statistical significance following adjustment for age. Logistic regression showed a trend towards warfarin use being independently associated with reduced prevalence of dementia (odds ratio 0.52, P = 0.08).

CONCLUSIONS

We found evidence of increased thrombin generation and fibrin turnover in subjects with AF and dementia compared with those without dementia. Long-term warfarin use may be protective against the development of dementia in subjects with AF.

Insulin resistance, haemostatic and inflammatory markers and coronary heart disease risk factors in Type 2 diabetic men with and without coronary heart disease

AIMS/HYPOTHESIS

We have examined markers of haemostasis and inflammation in men with diabetes, coronary heart disease (CHD) or both, and assessed their associations with insulin resistance in men with Type 2 diabetes.

METHODS

The study was carried out in 4066 British men aged 60 to 79 years who were not on warfarin or insulin, of whom there were 426 men with prevalent Type 2 diabetes and 842 with prevalent CHD.

RESULTS

Men with Type 2 diabetes were more likely to have multiple risk factors and higher levels of haemostatic and inflammatory markers than men without, irrespective of CHD status. Compared with men with CHD only, men with diabetes only showed increased levels of tissue plasminogen activator antigen, increased plasma and blood viscosity, and increased levels of coagulation factors VII, VIII and IX. They also had dyslipidaemia. In men with diabetes, increased insulin resistance (homeostasis model assessment, HOMA) was associated with increased levels of haemostatic markers and dyslipidaemia. The prevalence of CHD increased significantly with increasing tertiles of HOMA (adjusted odds ratio 1.32 [95% CI: 0.72-2.42] in the second, and 1.70 [95% CI: 0.92-3.44] in the third tertile; p=0.04 for trend).

CONCLUSIONS/INTERPRETATION

Increased insulin resistance among men with Type 2 diabetes is associated with increased prevalence of CHD and of activated haemostasis and dyslipidaemia. Reducing insulin resistance in men with diabetes may reduce their tendency to develop thrombosis and hence CHD risk.

C-reactive protein, fibrin D-dimer, and risk of ischemic heart disease: the Caerphilly and Speedwell studies

BACKGROUND

There is increasing interest in the predictive value of C-reactive protein (CRP) and fibrin D-dimer in the prediction of ischemic heart disease (IHD). We assessed their joint and independent associations with IHD in a large combined analysis of 2 population cohorts.

METHODS AND RESULTS

Men aged 49 to 66 years from the general populations of Caerphilly and Speedwell were studied between 1982 and 1988 and re-examined for new IHD events at fixed intervals of approximately 105 months (Caerphilly) and 75 months (Speedwell). 3213 men had CRP and D-dimer measured at baseline and 351 (11%) had a new IHD event. Mean levels of CRP and D-dimer were significantly higher among men in whom IHD developed. The relative odds of IHD in men in the top 20% of the distribution of CRP was 2.97 (95% CI, 2.04, 4.32) and for D-dimer was 2.40 (95% CI, 1.69, 3.40); CRP and D-dimer had additive effects on risk of IHD. Multivariate analysis reduced the size of the relative odds, which remained significant for D-dimer.

CONCLUSIONS

Both inflammatory and thrombogenic markers are important (and potentially additive) predictors of coronary risk.

Tissue plasminogen activator antigen and coronary heart disease Prospective study and meta-analysis

AIMS

To determine whether circulating tissue plasminogen activator (t-PA) antigen concentrations are prospectively related to risk of coronary heart disease (CHD) in the general population.

METHODS AND RESULTS

We measured baseline concentrations of t-PA antigen in the stored serum samples of 606 CHD cases and 1227 controls 'nested' in a prospective cohort of 5661 men monitored for 16 years, and conducted a meta-analysis of previous relevant studies to place our findings in context. Tissue plasminogen activator antigen values were strongly correlated with several vascular risk factors, including serum lipids, body mass index, alcohol consumption, and markers of systemic inflammation. In a comparison of men in the top third compared with those in the bottom third of baseline t-PA antigen values, the odds ratio for CHD was 2.20 (95% confidence interval (CI) 1.70-2.85) after adjustment for age and town only, but this fell to 1.48 (1.09-2.01) after further adjustment. Analysis of t-PA as a continuous variable gave similar results. Similarly, when published information on all seven available prospective cohort studies in general populations (2119 cases and 8832 controls in total) was synthesized, the combined odds ratio was 2.18 (1.77-2.69) after adjustment for age and sex only, and this fell to 1.47 (1.19-1.81) after further adjustment.

CONCLUSION

Although there is a statistically significant association between circulating concentrations of t-PA antigen and subsequent CHD, additional studies are needed to determine to what extent this is independent from more established risk factors.

Human CRP gene polymorphism influences CRP levels: implications for the prediction and pathogenesis of coronary heart disease

OBJECTIVE

C-reactive protein (CRP) concentrations are predictive of cardiovascular disease, and levels are heritable, in part. We identified novel polymorphisms in the CRP gene and assessed their influence on CRP level.

METHODS AND RESULTS

CRP was measured in 250 male army recruits before and after strenuous exercise and perioperatively in 193 coronary artery bypass graft (CABG) patients. Two novel polymorphisms were identified in the CRP gene, -717G>A in the promoter and +1444C>T in the 3'UTR. Among army recruits, CRP was higher in +1444TT homozygotes than +1444 C-allele carriers at baseline (1.04+/-0.38 versus 0.55+/-0.06, P=0.014) and at all time points after exercise (2.35+/-0.68 versus 1.07+/-0.12, 2.11+/-0.53 versus 0.88+/-0.09, and 1.77+/-0.44 versus 0.71+/-0.09, P=0.034, P=0.007, and P=0.013, at 2, 48, and 96 hours after exercise, respectively). In the CABG patients, mean CRP (mg/L) rose from 1.97+/-0.36 at baseline to 167.2+/-5.0 72 hours postoperatively. Genotype did not influence CRP at baseline; however, peak post-CABG CRP levels were higher in +1444TT homozygotes compared with +1444C-allele carriers (198+/-17 versus 164+/-5, P=0.03).

CONCLUSIONS

The CRP gene +1444C>T variant influences basal and stimulated CRP level. These findings have implications both for the prediction and pathogenesis of coronary heart disease.

Associations of plasma fibrinogen assays, C-reactive protein and interleukin-6 with previous myocardial infarction

BACKGROUND

The association of plasma fibrinogen with myocardial infarction (MI) may (like that of C-reactive protein, CRP) be a marker of subclinical inflammation, mediated by cytokines such as interleukin-6 (IL-6). There are well-recognized discrepancies between commonly performed fibrinogen assays. Increased ratio of clottable fibrinogen to intact fibrinogen (measured by a recently developed immunoassay) has been proposed as a measure of hyperfunctional fibrinogen, and is elevated in acute MI.

OBJECTIVE

To compare the associations of intact fibrinogen and four routine fibrinogen assays (two von Clauss assays; one prothrombin-time derived; and one immunonephelometric) in a case-control study of previous MI.

PATIENTS/METHODS

Cases (n=399) were recruited 3-9 months after their event; 413 controls were age- and sex- matched from the case-control study local population. Intact fibrinogen was measured in 50% of subjects.

RESULTS

All routine fibrinogen assays showed high intercorrelations (r=0.82-0.93) and significant (P<0.0001) increased mean levels in cases vs. controls. These four routine assays correlated only moderately with intact fibrinogen (r=0.45-0.62), while intact fibrinogen showed only a small, nonsignificant increase in cases vs. controls. Consequently, the ratio of each of the four routine assays to the intact fibrinogen assay was significantly higher (P<0.0003) in cases vs. controls. Each fibrinogen assay correlated with plasma levels of CRP and IL-6 (which were also elevated in cases vs. controls). Each routine fibrinogen assay remained significantly elevated in cases vs. controls after further adjustment for C-reactive protein and interleukin-6.

CONCLUSIONS

These data provide evidence for acquired, increased hyperfunctional plasma fibrinogen in MI survivors, which is not associated with markers of inflammatory reactions. The causes and significance of these results remain to be established in prospective studies.

Adrenocortical, autonomic, and inflammatory causes of the metabolic syndrome: nested case-control study

BACKGROUND

The causes of metabolic syndrome (MS), which may be a precursor of coronary disease, are uncertain. We hypothesize that disturbances in neuroendocrine and cardiac autonomic activity (CAA) contribute to development of MS. We examine reversibility and the power of psychosocial and behavioral factors to explain the neuroendocrine adaptations that accompany MS.

METHODS AND RESULTS

This was a double-blind case-control study of working men aged 45 to 63 years drawn from the Whitehall II cohort. MS cases (n=30) were compared with healthy controls (n=153). Cortisol secretion, sensitivity, and 24-hour cortisol metabolite and catecholamine output were measured over 2 days. CAA was obtained from power spectral analysis of heart rate variability (HRV) recordings. Twenty-four-hour cortisol metabolite and normetanephrine (3-methoxynorepinephrine) outputs were higher among cases than controls (+ 0.49, +0.45 SD, respectively). HRV and total power were lower among cases (both -0.72 SD). Serum interleukin-6, plasma C-reactive protein, and viscosity were higher among cases (+0.89, +0.51, and +0.72 SD). Lower HRV was associated with higher normetanephrine output (r=-0.19; P=0.03). Among former cases (MS 5 years previously, n=23), cortisol output, heart rate, and interleukin-6 were at the level of controls. Psychosocial factors accounted for 37% of the link between MS and normetanephrine output, and 7% to 19% for CAA. Health-related behaviors accounted for 5% to 18% of neuroendocrine differences.

CONCLUSIONS

Neuroendocrine stress axes are activated in MS. There is relative cardiac sympathetic predominance. The neuroendocrine changes may be reversible. This case-control study provides the first evidence that chronic stress may be a cause of MS. Confirmatory prospective studies are required.

von Willebrand factor and coronary heart disease: prospective study and meta-analysis

AIMS

To determine whether circulating von Willebrand factor concentrations are prospectively related to risk of coronary heart disease in the general population.

METHODS AND RESULTS

We measured baseline von Willebrand factor values in the stored serum samples of 625 men with major coronary events and in 1266 controls 'nested' in a prospective study of 5661 men aged 40-59 years, recruited from general practices in 18 British towns in 1978-1980 and followed up for 16 years for fatal coronary heart disease and non-fatal myocardial infarction. We conducted a meta-analysis of previous relevant studies to place our results in context. Men in the top third of baseline von Willebrand factor values (tertile cutoff >126 IU.dl(-1)) had an odds ratio for coronary heart disease of 1.83 (95% confidence interval 1.43-2.35; 2P <0.0001) compared with those in the bottom third (tertile cutoff <90 IU.dl(-1)), after adjustments for age and town. The odds ratio was little changed after further adjustment for risk factors (1.82, 95% CI 1.37-2.41), and was not significantly different in an analysis restricted to the 404 cases and 1007 controls without baseline evidence of coronary heart disease (odds ratio 1.53, 95% CI 1.10-2.12). A meta-analysis of all relevant population-based prospective studies (including the present study) yielded a combined odds ratio of 1.5 (95% CI 1.1-2.0). von Willebrand factor values were strongly correlated with Helicobacter pylori seropositivity and circulating concentrations of C-reactive protein (2 P<0.0001 for each), but not with smoking, blood lipids, or most other measured risk factors.

CONCLUSION

Though circulating von Willebrand factor concentrations may be associated with incident coronary heart disease, further studies are needed to determine the extent to which this is causal.

Effects of moderate weight loss on anginal symptoms and indices of coagulation and fibrinolysis in overweight patients with angina pectoris

OBJECTIVE

To evaluate the effects of moderate weight loss, in overweight patients with angina, on plasma coagulation, fibrinolytic indicies and pain frequency.

DESIGN

Single-stranded 12-week dietary intervention, an individualised eating plan with quantitative advice delivered by a dietitian. Target weight loss of 0.5 kg per week.

SETTING

Outpatient research clinic.

SUBJECTS

Fifty-four volunteers with angina pectoris were recruited. Five subjects withdrew, so 27 males, 22 females, mean body mass index (BMI) 29.3 (s.d. 4.3) kg/m(2) and age 60.3 (s.d. 6.5) y completed the intervention.

MEASUREMENTS

Body weight and frequency of anginal pain. Plasma fibrinogen, red cell aggregation (RCA), viscosity, factor VII activity, plasminogen activator inhibitor (PAI) activity, tissue plasminogen activator antigen (t-PA), plasma cholesterol, triglyceride and insulin.

RESULTS

After the 12-week dietary intervention period, mean body weight fell by 3.5 (s.d. 2.6) kg or 4.3% (P=0.0001), range -11.7 to +1.7 kg. Mean angina frequency fell by 1.8 (s.d. 3.6) from 3.2 to 1.4 episodes/week (P=0.009) and plasma cholesterol by 0.4 (s.d. 0.7) from 6.3 to 5.9 mmol/l (P=0.0001). HDL cholesterol and triglyceride were unchanged. Of the coagulation and fibrinolytic factors, factor VII activity and RCA were significantly reduced by 5 (s.d. 20), IU/dl (P=0.04) and 1.3 (s.d. 1.3) arbitrary units (P=0.014), respectively.

CONCLUSIONS

A conventional dietetic intervention, resulting in 4% weight loss, offers the potential to reduce atherosclerotic and thrombotic risk, and to reduce pain frequency, in angina patients. Given the importance of this result in a public health context, these results indicate that this may be a fruitful area for future nutrition research.

A performance evaluation of commercial fibrinogen reference preparations and assays for Clauss and PT-derived fibrinogen

The wide availability of fibrinogen estimations based on the prothrombin time (PT-Fg) has caused concern about the variability and clinical utility of fibrinogen assays. In a multi-centre study, we investigated fibrinogen assays using various reagents and analysers. Clauss assays generally gave good agreement, although one reagent gave 15-30% higher values in DIC and thrombolysis. Two commercial reference preparations had much lower potencies than the manufacturers declared, and plasma turbidity influenced parallelism in some Clauss assays. PT-Fg assays gave higher values than Clauss and showed calibrant dependent effects, the degree of disparity correlating with calibrant and test sample turbidity. Analyser and thromboplastin dependent differences were noted. The relationship between Clauss and PT-Fg assays was sigmoid, and the plateau of maximal PT-Fg differed by about 2 g/l between reagents. ELISA and immunonephelometric assays correlated well, but with a high degree of scatter. Antigen levels were higher than Clauss, but slightly lower than PT-Fg assays, which appeared to be influenced by degraded fibrinogen. Clauss assays are generally reproducible between centres, analysers and reagents, but PT-Fg assays are not reliable in clinical settings.

Hormonal replacement therapy, prothrombotic mutations and the risk of venous thrombosis

Hormone replacement therapy (HRT) increases the risk of venous thrombosis. We investigated whether this risk is affected by carriership of hereditary prothrombotic abnormalities. Therefore, we determined the two most common prothrombotic mutations, factor V Leiden and prothrombin 20210A in women who participated in a case-control study on venous thrombosis. Relative risks were expressed as odds ratios (OR) with 95% confidence intervals (CI95). Among 77 women aged 45-64 years with a first venous thrombosis, 51% were receiving HRT at the time of thrombosis, compared with 24% of control women (OR = 3.3, CI95 1.8-5.8). Among the patients, 23% had a prothrombotic defect, versus 7% among the control women (OR = 3.8, CI95 1.7-8.5). Women who had factor V Leiden and used HRT had a 15-fold increased risk (OR = 15.5, CI95 3.1-77), which exceeded the expected joint odds ratio of 6.1 (under an additive model). We conclude that the thrombotic risk of HRT may particularly affect women with prothrombotic mutations. Efforts to avoid HRT in women with increased risk of thrombosis are advisable.

Impact of angiotensin converting enzyme inhibition on post-coronary artery bypass interleukin 6 release

BACKGROUND

Angiotensin 1 converting enzyme (ACE) inhibitors reduce morbidity and mortality after coronary artery bypass graft surgery (CABG). This benefit may result from an anti-inflammatory action.

OBJECTIVE

To examine the effect of ACE inhibition on interleukin 6 (IL-6) concentrations after CABG.

PATIENTS AND METHODS

161 patients undergoing elective first time CABG were recruited, of whom 41 (25%) were receiving ACE inhibitor treatment; 21 patients with confounding postoperative complications were excluded. After these exclusions there were 33 patients (24%) on ACE inhibitor treatment. Plasma IL-6 was measured preoperatively and again six hours after CABG.

RESULTS

Baseline IL-6 concentrations (geometric mean (SEM)) were non-significantly lower among the patients receiving ACE inhibitors (3.7 (0.1) v 4.3 (0.1) pg/ml, p = 0.12). Overall, post-CABG IL-6 concentrations increased significantly (mean rise 177 (12) pg/ml, p < 0.0005). This response was blunted among ACE inhibitor treated patients. Median increases in IL-6 concentrations were 117 v 193 pg/ml, for treated v non-treated patients, respectively (Kruskal-Wallis, p = 0.02), with peak postoperative IL-6 concentrations lower among the subjects receiving ACE inhibitors than in untreated subjects (142 (19) v 196 (13) pg/ml, p = 0.02). The effect of ACE inhibitors remained significant after multivariate analysis (p = 0.018).

CONCLUSIONS

ACE inhibitor treatment is associated with a reduction in IL-6 response to CABG. The data suggest that this class of drug may have a direct anti-inflammatory effect, which could explain some of its clinical benefit.