Plasma fibrinogen and ischemic heart disease risk factors

Sex-specific associations between systolic, diastolic and pulse pressure and hemostatic parameters in the population-based KORA-Fit study: a cross-sectional study

BACKGROUND

Several prior studies postulated an effect of hypertension on coagulation factors. However, population-based studies investigating the sex-specific associations between hypertension and hemostatic parameters are scarce. Therefore, we investigated the relationship between blood pressure and parameters of coagulation, namely activated partial thromboplastin time (aPTT), international normalized ratio (INR), fibrinogen, factor VIII, antithrombin III, protein C, protein S, and D-dimer in men and women from the general population.

METHODS

Based on 803 participants (376 men, 427 women) from the KORA-Fit Study the sex-specific relationship between systolic, diastolic, and pulse pressure and commonly measured coagulation factors were investigated using multivariable-adjusted linear regression models.

RESULTS

Hypertensive males had significantly higher median fibrinogen levels and factor VIII activity in comparison to normotensive males. There was a statistically significant difference between females with and without hypertension regarding the parameter fibrinogen, D-dimers, Protein S activity, and factor VIII activity. In multivariable linear regression analyses no significant association between systolic blood pressure, diastolic blood pressure, as well as pulse pressure and the investigated hemostatic parameters was found in men. In women, a significant positive association could be observed between systolic blood pressure and D-dimer level [β-estimate per mmHg increase 3.37 (95% CI 0.935-5.804; p = 0.007)] and between pulse pressure and D-dimer level [β-estimate per mmHg increase 5.351 (95% CI 1.772-8.930; p = 0.003)].

CONCLUSIONS

It appears that sex differences exist in the association between blood pressure parameters and commonly measured coagulation markers in the general population. Further studies are needed to identify the underlying causes.

Sex-specific associations between serum lipids and hemostatic factors: the cross-sectional population-based KORA-fit study

BACKGROUND

Studies on the associations between lipid parameters and different hemostatic factors in men and women from the general population are scarce. It was therefore examined whether there are possible relationships between routinely measured serum lipids (total cholesterol, HDL-cholesterol, non-HDL-cholesterol, LDL-cholesterol, and triglycerides) and different hemostatic factors (activated partial thromboplastin time (aPTT), fibrinogen, factor VIII, antithrombin III (AT III), protein C, protein S, and D-dimer).

METHODS

The analysis was based on data from the Cooperative Health Research in the Region of Augsburg (KORA)-Fit study, which included 805 participants (378 men, 427 women) with a mean age of 63.1 years. Sex-specific associations between serum lipids and coagulation factors were investigated using multivariable linear regression models.

RESULTS

In men, total cholesterol was inversely related to aPTT but positively associated with protein C activity. HDL cholesterol was inversely related to aPTT and fibrinogen. LDL cholesterol, non-HDL cholesterol, and triglycerides showed a positive association with protein C and protein S activity. In women, LDL-cholesterol, total cholesterol, and non-HDL-cholesterol were positively related to AT III concentrations and protein C and S activity. Additionally, non-HDL-cholesterol was positively associated with factor VIII activity. HDL cholesterol was inversely related to fibrinogen. Triglycerides showed a positive relationship with protein C activity.

CONCLUSIONS

There seem to be sex differences regarding various associations between blood lipid levels and hemostatic factors. Further studies are needed to address the possible impact of these associations on cardiovascular risk and the underlying mechanisms.

Loneliness: An Immunometabolic Syndrome

Loneliness has been defined as an agonizing encounter, experienced when the need for human intimacy is not met adequately, or when a person’s social network does not match their preference, either in number or attributes. This definition helps us realize that the cause of loneliness is not merely being alone, but rather not being in the company we desire. With loneliness being introduced as a measurable, distinct psychological experience, it has been found to be associated with poor health behaviors, heightened stress response, and inadequate physiological repairing activity. With these three major pathways of pathogenesis, loneliness can do much harm; as it impacts both immune and metabolic regulation, altering the levels of inflammatory cytokines, growth factors, acute-phase reactants, chemokines, immunoglobulins, antibody response against viruses and vaccines, and immune cell activity; and affecting stress circuitry, glycemic control, lipid metabolism, body composition, metabolic syndrome, cardiovascular function, cognitive function and mental health, respectively. Taken together, there are too many immunologic and metabolic manifestations associated with the construct of loneliness, and with previous literature showcasing loneliness as a distinct psychological experience and a health determinant, we propose that loneliness, in and of itself, is not just a psychosocial phenomenon. It is also an all-encompassing complex of systemic alterations that occur with it, expanding it into a syndrome of events, linked through a shared network of immunometabolic pathology. This review aims to portray a detailed picture of loneliness as an “immunometabolic syndrome”, with its multifaceted pathology.

Relationship of perceived job stress to total coronary risk in a cohort of working men and women in Belgium

OBJECTIVE

To examine the relationships of job strain and iso-strain psychosocial work environment exposures to 'total coronary risk' (TCR) in a cohort of male and female workers in Belgium.

METHODS

The sample consists of 15,079 men and 4639 women aged 35-59 years employed in a wide range of occupations and free of any self-reported personal history of CHD. Karasek's job strain model was used to define high strain (high demands and low control), low strain, active and passive jobs. Iso-strain was defined as the combination of a high strain job with low worksite social support, and is compared to the other combinations. Total coronary risk is a composite measure based on a Framingham function assessing the risk of developing coronary heart disease (CHD) within the next 10 years; high and low levels of TCR were defined. Logistic regressions in each gender were applied to explore relationships, adjusting for age, level of education, occupational class and sector of employment.

RESULTS

In male workers, the age-adjusted prevalence of high TCR is highest in (1) in the lowest quartile group of job control and (2) in the 'high strain' group. The multivariate logistic regressions comparing high strain, active and passive work exposures to low strain work did not indicate a significant association with high TCR. Likewise, iso-strain jobs were neither found to be associated with high TCR.

CONCLUSION

Our cross-sectional analysis provides no support for the hypothesis that the psychosocial work environment is strongly associated with the TCR estimate in healthy workers.

Are fibrinogen and complete blood count parameters predictive in incarcerated abdominal hernia repair?

Therapeutic delays in cases of external incarcerated hernias typically result in increasing morbidity, mortality, and health expenditures. We investigated the diagnostic role of blood fibrinogen level, white blood count (WBC), mean platelet volume (MPV), and platelet distribution width (PDW) in patients with incarcerated hernia. Two groups, each containing 100 patients, were studied. Group A underwent elective, and group B underwent incarcerated and urgent external hernia repair. We observed high fibrinogen and WBC levels but low MPV and PDW values for patients in group B. Contrary to our expectations, we found lower MPV and PDW values in the complicated group than in the elective group. The morbidity rate and cost burden were higher in group B, and the results were statistically significant. Early operation should be recommended for patients with incarcerated external hernias if their fibrinogen and WBC levels are high.

Treating thrombus in the coronary arteries

Primary percutaneous coronary intervention (PCI) has greatly improved outcomes in patients with ST-elevation myocardial infarction (STEMI) and has, therefore, become the preferred reperfusion strategy for this patient group. The goal of primary PCI is to achieve a thrombolysis in myocardial infarction (TIMI) 3 flow and also to restore adequate perfusion at the myocardial level. Distal thrombus embolization during primary PCI occurs frequently and is also associated with compromised long-term outcomes. In this article, we provide an overview of the treatment of thrombus and the role of thrombectomy in PCI for STEMI.

Occupation and plasma fibrinogen in Japanese male and female workers: the Jichi Medical School Cohort study

This study explored the association between socioeconomic indices and plasma fibrinogen levels in Japanese male and female workers. Occupational category (white-collar vs. blue-collar) and position (manager vs. non-manager) were examined as relevant socioeconomic indices. The study population was a total of 1677 male and 1747 female workers aged 65 and younger taken from the Jichi Medical School Cohort study, a multicenter study designed to explore cardiovascular risk factors in the Japanese population. The association between socioeconomic indices and plasma fibrinogen levels was examined after taking into account several variables such as age, educational attainment, job strain, alcohol consumption, and smoking status and (for women) menopause status. Male white-collar workers had significantly lower fibrinogen levels than blue-collar workers. However, no significant association was found between occupational position and plasma fibrinogen for men. Occupational category interacted with occupational position for women. Among white-collar women, those in non-managerial positions showed higher levels of fibrinogen than those in managerial positions; among blue-collar women, there was no such difference. The association of occupational category and position on fibrinogen levels varied as a function of gender, implying that gender-specific socioeconomic differences could exist in cardiovascular risks in Japanese workers.

Burnout and risk of cardiovascular disease: evidence, possible causal paths, and promising research directions

Burnout is characterized by emotional exhaustion, physical fatigue, and cognitive weariness, resulting from prolonged exposure to work-related stress. The authors review the accumulated evidence suggesting that burnout and the related concept of vital exhaustion are associated with increased risk of cardiovascular disease and cardiovascular-related events. The authors present evidence supporting several potential mechanisms linking burnout with ill health, including the metabolic syndrome, dysregulation of the hypothalamic-pituitary-adrenal axis along with sympathetic nervous system activation, sleep disturbances, systemic inflammation, impaired immunity functions, blood coagulation and fibrinolysis, and poor health behaviors. The association of burnout and vital exhaustion with these disease mediators suggests that their impact on health may be more extensive than currently indicated.

Differences in leisure-time, household, and work-related physical activity by race, ethnicity, and education

BACKGROUND

Racial and ethnic minority groups have lower levels of leisure-time physical activity (LTPA) than whites, but it is unclear how much of this is explained by differences in socioeconomic status and health.

OBJECTIVE

To examine differences in LTPA, work-related physical activity (WRPA; heavy household chores and strenuous job activities), and total physical activity (TPA) by race, ethnicity, and education.

DESIGN, SETTING, AND PARTICIPANTS

Cross-sectional analyses of data from the 1992 Health and Retirement Study for a nationally representative cohort of 9,621 community-dwelling adults aged 51-61 years.

MEASUREMENTS

Physical activity scores for LTPA, WRPA, and TPA based upon self-reported frequency of light or vigorous recreational activities, heavy household chores, and strenuous job-related physical activities.

MAIN RESULTS

LTPA was lower for blacks and Hispanics compared to whites, and LTPA steadily declined with lower levels of education. WRPA showed the reverse pattern, being lowest for whites and persons with greater education. Education was far more important than race/ethnicity as a determinant of LTPA and WRPA in multivariate analyses. After adjusting for differences in overall health and physical functioning, mean TPA scores were similar across racial/ethnic and education categories; blacks (beta=1.0; 95% confidence interval [CI], 0.5 to 1.5) and Spanish-speaking Hispanics (beta=1.1; 95% CI, 0.3 to 1.9) had slightly higher levels of TPA than whites (P<.01 and P=.01, respectively).

CONCLUSIONS

Differences in educational attainment and health status accounted for virtually all of the racial and ethnic differences in LTPA. After accounting for WRPA, TPA was similar across race, ethnicity, and education subgroups.

Fibrinogen and other coronary risk factors

The association between plasma fibrinogen concentration and other coronary risk factors diverged in previous studies, and the impact from complex lipoprotein patterns has not been studied. Our research involved 24 healthy subjects without coronary heart disease (control) and 22 patients who had survived having acute myocardial infarction before the age of 41 years (cases), overall 40 men and 6 women with age range of 34 to 54 years. In multiple linear regression analyses concerning control subjects, family disposition, social class, a score based on serum triglyceride and high-density lipoprotein (HDL) cholesterol concentrations, and fasting capillary blood glucose concentration were significantly associated with plasma fibrinogen concentration (P < .00005, R2 = 0.81). For case subjects, the ratio between serum low-density lipoprotein cholesterol and high-density lipoprotein cholesterol concentrations was significantly associated with plasma fibrinogen concentration (P = .0018, R2 = 0.39). Thus, for healthy subjects, 4 coronary risk factors explained three quarters of the variation of plasma fibrinogen concentration, and for patients with a previous acute myocardial infarction, another coronary risk factor explained one third of the variation. In conclusion, the pattern of coronary risk factors associated with plasma fibrinogen concentration differed between those without coronary heart disease and those with a previous acute myocardial infarction.

Body fat is the main predictor of fibrinogen levels in healthy non-obese men

Previous studies have demonstrated that circulating levels of C-reactive protein (CRP), a marker of cardiovascular risk, are strictly related to body fatness. Elevated fibrinogen levels are also predictive of future cardiovascular events. The metabolic background of this relationship and the predictors of fibrinogen levels have not been well established. We aimed to evaluate whether fibrinogen levels are associated with body fat content and distribution and to determine the independent predictors of fibrinogen levels in a sample of healthy, non-obese, nonsmoking young adult men. Age, anthropometric measures (body mass index [BMI], waist-to-hip ratio [WHR]), total and regional fat content (determined by dual x-ray absorptiometry [DXA]), metabolic variables (total cholesterol [T-Chol], low-density lipoprotein cholesterol [LDL-C], and high-density lipoprotein cholesterol [HDL-C]; triglycerides [TG]; glucose and insulin levels; fasting insulin resistance index [FIRI]; blood pressure), interleukin-6 (IL-6), and acute-phase reactants levels (fibrinogen, highly sensitive [hs]-CRP) were determined in 87 healthy nonsmoking, non-obese subjects. Linear regression analysis was used to evaluate the association between body fat, fibrinogen, and metabolic variables, and multiple regression model analysis was used to examine the independent predictors of fibrinogen levels. Eighty-seven (30.5 +/- 3.5 years) non-obese (mean BMI 24.1 +/- 3.5) men were studied. Fibrinogen levels were strongly associated with measures of body fat and with metabolic variables. Total body fat (P < .0001) and LDL-cholesterol (P < .01) were the independent predictors of fibrinogen levels, accounting for 29.5% and 10.9% of its variance, respectively. Total body fat was the best independent predictor of hs-CRP levels, accounting for 32.5 % of its variance. We conclude that in healthy, non-obese subjects, body fat content is the main predictor of fibrinogen levels, as well of hs-CRP levels. These findings support the speculation that there is a direct mechanism by which adipose tissue might regulate the levels of circulating acute-phase reactants.

Sustained plasma fibrinogen elevation in subtotal nephrectomized rats: effect of cilazapril, an angiotensin-converting enzyme inhibitor

The present study was undertaken to examine whether plasma fibrinogen persistently elevates in subtotal nephrectomized rats, an animal model with inflammatory renal changes. Eight weeks after the induction of 5/6 nephrectomy in male Wistar rats, plasma fibrinogen concentration was determined for the next 12 weeks in the animals received vehicle or an angiotensin-converting enzyme inhibitor, cilazapril (1 or 10 mg/kg per day) orally. In the vehicle-treated nephrectomized rats, plasma fibrinogen concentration significantly (P<0.001) increased (from 127.3 +/- 4.6 [S.E.M.] to 182.3 +/- 5.2 mg/dL) compared with that in the control rats (from 118.0 +/- 2.0 to 153.5 +/- 5.4 mg/dL). Cilazapril attenuated the increases in plasma fibrinogen concentration in a dose-dependent manner. Serum concentration of monocyte chemoattractant protein-1, a key macrophage chemoattractant and activator, increased in the vehicle-treated nephrectomized rats, which was also reduced by cilazapril. These results suggest that plasma fibrinogen elevates persistently in the nephrectomized rats. Local inflammation may be involved in the hepatic fibrinogen synthesis in this model.

Leisure-time physical activity and reduced plasma levels of obesity-related inflammatory markers

OBJECTIVE

This study investigated the relationship between physical activity and the obesity-related inflammatory markers C-reactive protein, interleukin-6, and soluble tumor necrosis factor receptors (sTNF-Rs) 1 and 2. Furthermore, we examined the relationship between physical activity and insulin sensitivity (insulin, C-peptide, and hemoglobin A(1c) levels) and whether inflammatory markers mediate this association.

RESEARCH METHODS AND PROCEDURES

Biomarkers were measured in 405 healthy men and 454 healthy women from two large ongoing prospective studies. Information about physical activity and other variables was assessed by questionnaires.

RESULTS

After adjustment for other predictors of inflammation, physical activity was inversely associated with plasma levels of sTNF-R1, sTNF-R2, interleukin-6, and C-reactive protein (p = 0.07, p = 0.004, p = 0.04, and p = 0.009). After further adjustment for BMI and leptin, as a surrogate for fat mass, most of these associations were no longer significant. Physical activity was also inversely related to insulin and C-peptide levels (p = 0.008 and p < 0.001); however, in contrast to BMI and leptin, levels of inflammatory markers explained only very little of this inverse relationship.

DISCUSSION

These results suggest that frequent physical activity is associated with lower systemic inflammation and improved insulin sensitivity. These associations can partially be explained by a lower degree of obesity in physically active subjects. Although inflammatory markers may mediate obesity-dependent effects of physical activity on inflammatory related diseases such as type 2 diabetes or coronary heart disease, our study suggests that they do not directly account for the beneficial effects of physical activity on insulin resistance.

Influence of depressive mood on the association of CRP and obesity in 3205 middle aged healthy men

We studied concentrations of C-reactive proteins (CRP) in a population-based sample of 3204 men aged 45-74 years. Obesity was identified in 726 (23%) men (body mass index (BMI) >30 kg/m(2)). Stratification of the sample into three levels of depressive mood revealed a significant association between increased CRP in the obese sample with highest level of depression in comparison to the low level obese depression group (p=.013). The obesity x depression interaction was significant (p=.021). Multivariate analysis confirmed this effect after adjusting for possible confounding variables (age, high blood pressure, smoking, physical inactivity, low social class, and low alcohol intake) (p=.008). In the non-obese sample, there was no association between depressive mood and concentrations of CRP. These findings suggest a possible synergistic effect of obesity and depressive mood on chronic low level inflammation which may play a crucial role in the pathogenesis of atherosclerosis.

Combined segregation and linkage analysis of fibrinogen variability in Israeli families: evidence for two quantitative-trait loci, one of which is linked to a functional variant (-58G > A) in the promoter of the alpha-fibrinogen gene

The association of alpha- and beta-fibrinogen polymorphisms with plasma fibrinogen levels was examined in a sample of 452 family members from 80 Israeli kindreds. The measured genotype analysis indicated that the beta-fibrinogen -455G > A polymorphism was not associated with fibrinogen levels, while the alpha-fibrinogen -58G > A locus showed a significant association with fibrinogen levels (chi2= 17.7; df = 3; p < 0.001), with the -58A allele being associated with higher levels. Segregation analysis in this sample suggested a recessive quantitative-trait locus (QTL) with a major effect that controlled the sex- and age-adjusted fibrinogen levels. Results from a combined segregation/linkage analysis indicated that a single QTL influencing plasma fibrinogen is in gametic equilibrium with the beta-fibrinogen -455G > A and alpha-fibrinogen -58G > A polymorphisms. An extended analysis with a two-QTL model significantly improved the fit of the model (p < or = 0.001), and gave support for linkage between the fibrinogen QTL and the alpha-fibrinogen polymorphism. In vitro analysis with a DNA fragment containing this variant, linked to a reporter gene, showed 2-fold higher expression of the A allele compared to the G allele in the liver cell line HepG2, both under basal conditions and after stimulation with interleukin 6. These results demonstrate that two QTLs are jointly involved in determining plasma fibrinogen levels in this sample of families, one of which is located close to a functional variant in the alpha-fibrinogen locus.

Loneliness, lack of emotional support, lack of companionship, and the likelihood of having a heart condition in an elderly sample

Social isolation has been linked to a variety of adverse health outcomes, including cardiovascular disease. Researchers have attributed this association to the feelings of loneliness that accompany social isolation, but they have rarely assessed loneliness directly. In a sample of 180 older adults, feelings of loneliness and two kinds of social deficits that underlie loneliness--limited emotional support and limited companionship--were examined in relation to the likelihood of having a coronary condition. Potential physiological, behavioral, and affective mediators were examined as well. Greater loneliness was found to be associated with an increased probability of having a coronary condition, as were low levels of both emotional support and companionship. Mediators of these links were not identified, however, in this sample. These results underscore the value of examining the specific social deficits that underlie loneliness in investigations of the relation between loneliness and cardiovascular health in later life.

Influence of socioeconomic status and job control on plasma fibrinogen responses to acute mental stress

OBJECTIVE

An elevation in plasma fibrinogen may be one of the pathways through which low socioeconomic status increases cardiovascular disease risk. This study assessed the influence of socioeconomic status, job control, and social isolation on fibrinogen responses to acute stress.

METHODS

The study was conducted with 125 white men and 96 white women aged 47 to 58 years, drawn from the Whitehall II cohort. Socioeconomic status was indexed by grade of employment, with 82 high, 75 intermediate, and 64 low grade participants. Plasma fibrinogen and hematocrit were assessed at baseline, immediately after performance of color-word and mirror tracing tasks, and 45 minutes later.

RESULTS

Plasma fibrinogen increased from baseline to stress (from 2.85 +/- 0.57 to 2.92 +/- 0.58 g/liter), remaining elevated 45 minutes after stress (2.89 +/- 0.58 g/liter, p <.001). Fibrinogen concentration was greater in the low than in the high or intermediate employment grade groups, independently of sex, age, body mass index, smoking status, and hematocrit. Fibrinogen responses to acute stress did not differ across employment grades. Women had higher fibrinogen levels than men, but this pattern was abolished in women taking hormone replacement therapy. Men experiencing low job control showed greater fibrinogen responses to acute stress than did those with high job control (p =.003). Fibrinogen levels were greater in socially isolated individuals, but social isolation did not affect responses to acute stress.

CONCLUSIONS

Socioeconomic status and acute stress had independent effects on the plasma fibrinogen level. Low job control may influence cardiovascular disease risk in men partly through provoking greater fibrinogen stress responses.

Obesity, haemostasis and the fibrinolytic system

Obese patients are at risk for the development of cardiovascular diseases, which can in part be explained by disturbances in the haemostatic and fibrinolytic systems. Indeed, obese subjects tend to have higher values of fibrinogen, factor VII, factor VIII, von Willebrand factor and plasminogen activator inhibitor compared to non-obese subjects. Abdominal obesity, in particular, has been shown to be associated with disturbances in fibrinogen, factor VIII and von Willebrand factor, while less consistent results have been found for factor VII. Recently it has been demonstrated that the adipocyte itself is able to produce plasminogen activator inhibitor-1, possibly explaining the high levels found in obesity. Different studies have investigated the association between haemostatic and fibrinolytic parameters and the insulin resistance syndrome, often present in obese subjects. Fibrinogen has been found to be related to insulin, but it has been suggested that this relationship is not independent of the accompanying inflammatory reaction. Results from studies on the relationship between insulin resistance and factor VII, factor VIII and von Willebrand factor levels are inconsistent. In contrast, plasminogen activator inhibitor-1 has been found to correlate with all components of the insulin resistance syndrome, and can be considered as a true component of this metabolic syndrome. Weight loss seems to have a beneficial effect on factor VII--probably mediated through a reduction in triglycerides. Data on factor VIII and von Willebrand factor are scarce but weight loss does not seem to have an effect. Fibrinogen does not seem to be reduced by modest weight loss and a more substantial weight loss seems necessary to lower fibrinogen levels. In contrast, both modest and substantial weight loss have been found to significantly reduce plasminogen activator inhibitor-1 levels. In conclusion, the increased cardiovascular risk observed in obesity could in part be explained by the association between insulin resistance and components of the fibrinolytic and haemostatic systems. Whether this relationship is truly causal or indirect needs to be elucidated further.

Stress, inflammation and cardiovascular disease

Various psychosocial factors have been implicated in the etiology and pathogenesis of certain cardiovascular diseases such as atherosclerosis, now considered to be the result of a chronic inflammatory process. In this article, we review the evidence that repeated episodes of acute psychological stress, or chronic psychologic stress, may induce a chronic inflammatory process culminating in atherosclerosis. These inflammatory events, caused by stress, may account for the approximately 40% of atherosclerotic patients with no other known risk factors. Stress, by activating the sympathetic nervous system, the hypothalamic-pituitary axis, and the renin-angiotensin system, causes the release of various stress hormones such as catecholamines, corticosteroids, glucagon, growth hormone, and renin, and elevated levels of homocysteine, which induce a heightened state of cardiovascular activity, injured endothelium, and induction of adhesion molecules on endothelial cells to which recruited inflammatory cells adhere and translocate to the arterial wall. An acute phase response (APR), similar to that associated with inflammation, is also engendered, which is characterized by macrophage activation, the production of cytokines, other inflammatory mediators, acute phase proteins (APPs), and mast cell activation, all of which promote the inflammatory process. Stress also induces an atherosclerotic lipid profile with oxidation of lipids and, if chronic, a hypercoagulable state that may result in arterial thromboses. Shedding of adhesion molecules and the appearance of cytokines, and APPs in the blood are early indicators of a stress-induced APR, may appear in the blood of asymptomatic people, and be predictors of future cardiovascular disease. The inflammatory response is contained within the stress response, which evolved later and is adaptive in that an animal may be better able to react to an organism introduced during combat. The argument is made that humans reacting to stressors, which are not life-threatening but are "perceived" as such, mount similar stress/inflammatory responses in the arteries, and which, if repetitive or chronic, may culminate in atherosclerosis.

Soy protein intake by perimenopausal women does not affect circulating lipids and lipoproteins or coagulation and fibrinolytic factors

Soy protein favorably alters serum lipids and lipoproteins in hypercholesterolemic individuals, thereby reducing cardiovascular disease risk. The primary purpose was to determine the effect of soy protein (40 g/d) on circulating lipids and lipoproteins or coagulation and fibrinolytic factors in normocholesterolemic and mildly hypercholesterolemic perimenopausal women. We also determined the contribution of coagulation and fibrinolytic and other factors (e.g., body size and composition; serum estrogens, ferritin, iron; dietary intake) to lipid profiles. Subjects were randomly assigned to treatment: isoflavone-rich soy (n = 24), isoflavone-poor soy (n = 24), or whey control (n = 21) protein. We measured circulating lipids and lipoproteins at baseline, wk 12 and wk 24, and coagulation/fibrinolytic factors at baseline and wk 24. Coagulation and fibrinolytic factors were not adversely affected by treatment. Treatment did not alter lipid profiles in mildly hypercholesterolemic (n = 30) or in all subjects combined. Time significantly (P < 0.001) affected serum total cholesterol, triacylglycerol, LDL cholesterol and HDL cholesterol concentrations. We could not attribute changes over time to various factors, but at baseline accounted for 57% of the variability in HDL cholesterol (P < or = 0.0001) and for 50% in the total to HDL cholesterol ratio (P < or = 0.0001). Dietary vitamin E and % energy from fat had positive effects, whereas plasma plasminogen activator inhibitor-1, fibrinogen, body weight and serum ferritin had negative effects on HDL and total to HDL cholesterol. Isoflavone-rich or isoflavone-poor soy protein had no effect on lipid profiles or coagulation and fibrinolytic factors, whereas the effect of time suggested that the hormonal milieu during the menopausal transition may have overridden any detectable treatment effect on lipids. The relationship between coagulation factors and serum lipids should be examined further as indices of cardiovascular disease risk in midlife women.

Effects of psychological stress and psychiatric disorders on blood coagulation and fibrinolysis: a biobehavioral pathway to coronary artery disease?

OBJECTIVE

A hypercoagulable state before overt thrombosis resulting from an imbalance between the coagulation and fibrinolysis systems is related to cardiovascular disease progression and acute coronary syndromes. Psychological stressors and depressive and anxiety disorders also are associated with coronary artery disease. This review explores whether changes in blood coagulation, anticoagulant, and fibrinolytic activity may constitute psychobiological pathways that link psychological factors with coronary syndromes.

METHODS

Literature on coagulation, anticoagulation, and fibrinolysis measures in conjunction with psychological factors (mental stress, psychosocial strain, and psychiatric disorders) was identified by MEDLINE search back to 1966 and through checking the bibliographies of these sources. Sixty-eight articles were critically reviewed.

RESULTS

In healthy subjects, acute mental stress simultaneously activates coagulation (ie, fibrinogen or von Willebrand factor) and fibrinolysis (ie, tissue-type plasminogen activator) within a physiological range. In patients with atherosclerosis and impaired endothelial anticoagulant function, however, procoagulant responses to acute stressors may outweigh anticoagulant mechanisms and thereby promote a hypercoagulable state. Chronic psychosocial stressors (job strain or low socioeconomic status) are related to a hypercoagulable state reflected by increased procoagulant molecules (ie, fibrinogen or coagulation factor VII) and by reduced fibrinolytic capacity. There is also some evidence that points to hypercoagulability in depression.

CONCLUSIONS

Different categories of psychological measures to varying extent are associated with characteristic patterns of coagulation and fibrinolysis activity. Associations between psychological factors and several coagulation and fibrinolysis variables related to atherosclerosis provide a plausible biobehavioral link to coronary artery disease.

Association between job strain status and cardiovascular risk in a population of Taiwanese white-collar workers

Using data from a survey of a white-collar working population in Taiwan (438 women, 526 men), the relation between job strain status and cardiovascular risk factors (high serum total cholesterol, low serum high-density lipoprotein (HDL) cholesterol, and high plasma fibrinogen) was examined. Job strain indicators, defined by Karasek's model, included psychological demand and decision latitude. Blood pressure, cholesterol and fibrinogen were analyzed as continuous variables, whereas psychological demand and decision latitude were dichotomized into 2 levels and job strain into 4 exposure categories. Plasma fibrinogen was significantly and positively associated with job strain status in both male and female workers and also with decision latitude in female workers only. No consistent association between job strain status and total serum and HDL cholesterol was detectable. In conclusion, plasma fibrinogen is a possible intermediate factor linking occupational stress to elevated cardiovascular risk.

Idiopathic polypoidal choroidal vasculopathy: a disease with diverse clinical spectrum and systemic associations

PURPOSE

To report the clinical findings, angiographic results, clinical course, response to laser photocoagulation and systemic-associations in a group of patients with idiopathic polypoidal choroidal vasculopathy (IPCV).

METHODS

All patients with IPCV attending the macular clinic underwent a complete ocular examination, and fluorescein and indocyanine green angiography. In addition, a systemic examination including blood pressure, full blood count, plasma viscosity and coagulation status of patients was carried out.

RESULTS

We present a series of 5 patients (7 eyes) with clinical and angiographic evidence of IPCV with follow-up of 3-6 years. We report diverse demographic and clinical manifestations. One patient had polypoidal lesions found at the peripheral retina (anterior to equator) of both eyes. Three patients were treated with laser photocoagulation and achieved stable vision; 2 patients who had no laser treatment experienced deteriorated vision, one of whom had a vitrectomy. One patient was hypertensive, 2 patients were found to have raised plasma viscosity, and 1 patient had thrombocytopenia.

CONCLUSIONS

The clinical spectrum of IPCV is wider than previously documented. It is a distinct clinical entity which should be differentiated from other forms of haemorrhagic and exudative maculopathy. The availability of indocyanine green angiography has allowed increased recognition of these cases. Early selective laser treatment on lesions affecting maculae-could stabilise the disease. Its association with systemic cardiovascular disease and blood disorder may predispose to the recurrence of haemorrhagic events in this entity.

Plasma viscosity and its biochemical predictors: associations with lifestyle factors in healthy middle-aged men

The association of lifestyle factors and biochemical variables with plasma viscosity was examined in a sample of middle-aged males of high social status. Analyses were performed on a subsample of men that had relevant rheological and biochemical variables determined during a preventive medical assessment conducted between 1992 and 1996. Among 622 subjects (64 smokers), measures of physical activity or predicted VO2max and adiposity (sum of subcutaneous skinfolds) were the lifestyle factors significantly associated with plasma viscosity (both P < 0.001). Among the biochemical variables, serum total protein and plasma fibrinogen concentrations accounted for most of the explained variability in plasma viscosity within subjects (combined adjusted r2 = 65.5%). Logarithm-transformed triglyceride, leukocyte count and serum globulin together contributed an additional 3.0% of the variance in plasma viscosity. Serum total protein, In triglycerides and leukocyte count decreased significantly across higher quartiles of predicted VO2max (all P < 0.0001), with trends towards lower fibrinogen and globulin concentrations (P = 0.054 and P = 0.050, respectively). Higher levels of adiposity were also significantly associated with higher levels of serum total protein (P < 0.0001), globulin (P < 0.0001), fibrinogen (P < 0.01), leukocyte count (P < 0.05), and triglycerides (P < 0.0001). The association of lifestyle factors with the biochemical predictors of plasma viscosity may result directly from a pro-inflammatory state of adipose tissue origin and/or a larger plasma volume related to higher levels of cardiorespiratory fitness. Randomised controlled trials of the effects of regular physical activity of different intensities on plasma viscosity, with reference to body composition, are now required.

Job strain and risk indicators for cardiovascular disease in young female nurses

This study examined the possible effects of job demands, decision latitude, and job-related social support on risk indicators for cardiovascular disease (CVD) in 165 female nurses. Job strain was measured with the Job Content Questionnaire; CVD risk was measured with insulin, total cholesterol, triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), fibrinogen, tissue-type plasminogen activator (tPA) antigen, tPA activity, plasminogen activator inhibitor-1 antigen, and blood pressure. Multivariate analysis of covariance and regression analyses revealed no effects of either job strain or social support on these risk indicators. All risk indicators deteriorated with age and body mass index. Oral contraceptive use improved fibrinolytic potential and increased HDL-C but had adverse effects on TG levels. Results suggest that in healthy young women job strain is not associated with an unfavorable metabolic or fibrinolytic risk profile.

The relationship between employment grade and plasma fibrinogen level among Japanese male employees. YKKJ Research Group

Plasma fibrinogen is an important risk factor for cardiovascular disease, and is associated with socioeconomic status in Europe and the United States. We evaluated whether the relationship between socioeconomic status and plasma fibrinogen level exists in Japanese male employees, and whether this relationship is independent of other correlates of plasma fibrinogen. This cross-sectional study was conducted on full-time male employees aged 20-58 in a metal-products factory between April 1996 and March 1997. Altogether 4375 employees (92.9%) participated. Low employment grade and low educational background were associated with increased age-adjusted plasma fibrinogen level. Adjusting for body mass index, waist to hip ratio, height, smoking habit, alcohol consumption, physical activity at leisure and systolic blood pressure did not attenuate these associations much. Adjusting for white blood cell count and hemoglobin Alc reduced the associations of both employment grade and educational background with plasma fibrinogen level, nevertheless these relationships remained significant.

Contribution of fibrinogen and lipoproteins to plasma viscosity in hypercholesterolemia and hypertriglyceridemia: evaluation by selective depletion of low-density lipoproteins or fibrinogen

Epidemiological studies suggest that the plasma fibrinogen concentration is the main determinant of plasma viscosity (PV), but the concentration of other macromolecules (eg, immunoglobulins) and low-density lipoprotein (LDL) cholesterol and triglycerides are also correlated with PV. However, only a few data exist concerning the in vitro effects of these plasma constituents on PV. Therefore, we investigated PV before and after the specific elimination of fibrinogen and LDL in hypercholesterolemic and hypertriglyceridemic plasma. First, hypercholesterolemic samples (n = 7) were pumped simultaneously through 2 columns: a fibrinogen-depleting column containing the pentapeptide Gly-Pro-Arg-Pro-Lys (GPRPK) and a LDL-depleting column containing specific antibodies against apolipoprotein B-100. In the plasma and in each fraction from the column, the cholesterol level was measured enzymatically, fibrinogen was determined by immunonephelometry, and PV was analyzed using a low-shear rotation viscosimeter. After the fibrinogen-depleting column, the fibrinogen concentration decreased from 3.21 +/- 0.20 to 0.94 +/- 0.16 g/L (P < .005), inducing a decrease in PV from 1.27 +/- 0.02 to 1.17 +/- 0.01 mPas (milliPascal seconds) (P < .005). Despite a marked reduction of the LDL cholesterol after the LDL-depleting column (from 6.40 +/- 0.23 to 4.08 +/- 0.32 mmol/L, P < .005), PV remained unchanged. Second, hypertriglyceridemic samples (n = 7) were pumped through the fibrinogen-depleting column, which reduced the fibrinogen concentration from 4.29 +/- 0.79 to 1.62 +/- 0.69 g/L (P < .001) and PV from 1.42 +/- 0.06 to 1.03 +/- 0.05 mPas (P < .01) while the triglyceride concentration remained unchanged. Our results confirm the epidemiological correlation between the fibrinogen concentration and PV in patients with hypercholesterolemia and hypertriglyceridemia. The influence of fibrinogen on PV seems much more pronounced than the direct effect of lipoprotein concentrations. Therefore, the elevated PV in patients with hypercholesterolemia and especially with hypertriglyceridemia seems mainly due to elevated fibrinogen levels.

Leisure time physical activity, cardiorespiratory fitness, and plasma fibrinogen concentrations in nonsmoking middle-aged men

PURPOSE

The relationship of both leisure time physical activity and predicted maximum oxygen consumption (VO2max) with plasma fibrinogen concentration was examined within a cohort of employed middle-aged men.

METHODS

Analyses were performed on a subsample of 635 nonsmoking men (46.7 +/- 7.7 yr) who completed a preventive medical assessment between 1992 and 1996.

RESULTS

Among nonsmokers, mean age-adjusted fibrinogen concentration decreased significantly with higher physical activity index (PAL) categories and quartiles of predicted VO2max (mL x kg(-1) x min(-1)) (both P = 0.001). Mean age-adjusted plasma fibrinogen concentrations were significantly different (P < 0.05) between inactive and vigorous PAI groups and extreme quartiles of predicted VO2max (mL x kg(-1) x min(-1)). These relationships were no longer significant after adjustment for the confounding effect of other ischemic heart disease risk factors. Stepwise multiple regression analyses showed that age, sum of skinfolds, and blood leukocyte count were the strongest predictors of plasma fibrinogen concentration.

CONCLUSION

These data do not confirm a significant independent association of both physical activity and predicted VO2max (mL x kg(-1) x min(-1)) with fibrinogen concentrations among nonsmoking middle-aged men of similar high social class.

Physical activity, cardiorespiratory fitness, and the primary components of blood viscosity

PURPOSE

The relationship of both self-reported leisure time physical activity (LTPA) and predicted maximum oxygen consumption (VO2max) with plasma viscosity and hematocrit (Hct) concentration was examined within a cross-sectional sample of employed middle-aged men.

METHODS

Analyses were performed on a subsample of nonsmoking men who completed a preventive medical assessment between 1992-1996.

RESULTS

Among nonsmokers the mean age-adjusted levels of plasma viscosity (N = 590) and Hct concentration (N = 632) were significantly lower with higher Physical Activity Index (PAI) categories (P = 0.001 and P = 0.01, respectively). Following adjustment for conventional IHD risk factors and blood leukocyte count, a significant inverse relationship remained for Hct (P = 0.044) but not plasma viscosity. Mean age-adjusted plasma viscosity and Hct concentration also showed a significant decrease with higher quartiles of predicted VO2max (mL x kg(-1) x min(-1))(P = < 0.00005 and P = 0.0004, respectively). Following adjustment for all confounding variables mean plasma viscosity and Hct concentration remained significantly lower with higher quartiles of predicted VO2max (mL x kg(-1) x min(-1))(P = < 0.00005 and P = 0.047).

CONCLUSIONS

These data confirm the inverse relationship between LTPA and/or predicted VO2max with plasma viscosity and Hct concentration within nonsmoking middle-aged men of high socioeconomic status.

Association between job characteristics and plasma fibrinogen in a normal working population: a cross sectional analysis in referents of the SHEEP Study. Stockholm Heart Epidemiology Program

STUDY OBJECTIVE

To explore the association between job characteristics and plasma fibrinogen concentrations.

DESIGN

Cross sectional design.

SETTING

The Greater Stockholm area.

SUBJECTS

A total of 1018 men and 490 women aged 45-70 who were randomly selected from the general population during 1992-1994. They were all employed and had no history of myocardial infarction.

MAIN RESULTS

The self reported job characteristics were measured by a Swedish version of the Karasek demand-control questionnaire. For inferred scoring of job characteristics, psychosocial exposure categories (job control and psychological demands) were assigned by linking each subject's occupational history with a work organisation exposure matrix. Job strain was defined as the ratio between demands and control. In univariate analyses, expected linear trends were found in three of four tests of association between high plasma fibrinogen and low control (the self reported score for women and the inferred score for both sexes), in one of four tests of association between high plasma fibrinogen and high demands (the inferred score for women) and in two of four tests of association between high plasma fibrinogen and job strain (the inferred score for both sexes). Multiple logistic regression analyses showed that men in the inferred job strain group have an increased risk of falling into the increased plasma fibrinogen concentration group (above median level of the distribution) (odds ratio (OR) 1.2; 95% CI 1.0, 1.5) after adjustment for the variables that were associated with plasma fibrinogen in the univariate analyses. In women, low self reported control, high inferred demand, and inferred job strain were significantly associated with increased plasma fibrinogen concentration (OR 1.3; 95% CI 1.0, 1.8, OR 1.5; 95% CI 1.0, 2.2, OR 1.5; 95% CI 1.1, 2.2, respectively).

CONCLUSIONS

These results indicate that adverse job characteristics may be related to plasma fibrinogen concentrations and this relation is more relevant in female workers. The clearest evidence for psychosocial effects on plasma fibrinogen seems to be with job control and the associations are clearer for the objective than for the self report variables.

Job strain and biological coronary risk factors: A cross-sectional study of male and female workers in a japanese rural district

To investigate the association between job strain and biological coronary risk factors, a demand-control questionnaire was applied to 138 male (mean age 51.5) and 166 female (50.8) workers in Japanese rural town. In Model I, workers rated as both above the median on demands and below the median on control were defined as a strain group and compared to the rest. In Model II, the effect of a multiplicative term of demands by control was tested once the component main effects were controlled. In both models, possible confounders were controlled. Men in the strain group had higher blood glucose than did the others (Model 1), and the multiplicative term was significantly associated with diastolic blood pressure in men and with Lipoprotein(a) in women (Model II). The results suggest that the demand-control model predicts coronary risk factors in Japanese rural workers, and the associations are different between genders.

Thrombin generation and activation of the thrombomodulin protein C system in open heart surgery depend on the underlying cardiac disease

The exposure of blood to foreign surfaces during extracorporeal circulation (ECC) leads to an activation of the coagulation system. In arteriosclerotic patients thrombin activation is increased and plasma fibrinogen is elevated, while protein C levels are reduced. In this study we investigated the influence of different cardiac diseases on ECC-induced thrombin generation and activation of the thrombomodulin-protein C system. Twenty-four patients undergoing either elective coronary artery bypass grafting (CABG) or elective aortic valve replacement (AVR) were included in the study. Blood samples were taken at different time intervals before, during and after ECC, and in the postoperative period. Plasma concentrations of thrombin-antithrombin III-complex (TAT), modified antithrombin (ATM), prothrombin fragment F1+2, free protein S, thrombomodulin, and protein C-antigen were determined by ELISA. Fibrinogen and antithrombin III levels were detected by nephelometry. Both groups were comparable with respect to biometric and ECC-related data. TAT concentrations were elevated in both groups after induction and increased during surgery (p<0.001). As a marker of thrombin generation levels of F1+2 were higher in the CABG group during cardiopulmonary bypass (p=0.003). In CABG patients ATM peaks were higher during ECC (p=0.0024). Significantly higher plasma thrombomodulin concentrations were found in CABG patients after induction (p<0.001), while protein S concentrations were higher in the AVR group (p=0.002). Protein C levels and antithrombin III concentrations did not differ between the groups. Patients undergoing CABG were found to have lower protein S levels and increased plasma thrombomodulin concentrations as markers of endothelial damage. In these patients contact activation and as a consequence thrombin generation takes place at a higher level, indicating a hypercoagulable state. Thromboembolic events in the perioperative period may be caused by different hemostatic changes in CABG patients.

Effects of lipids and lipoproteins on thrombosis and rheology

Atherosclerotic plaque rupture and erosions precipitate thrombus formation and may lead to an acute ischemic syndrome. Lipids and lipoproteins modulate the expression and/or function of thrombotic, fibrinolytic and rheologic factors, and thereby influence hemostasis and potential tissue damage resulting from vascular injury. Triglyceride-enriched lipoproteins are accompanied by elevations in factor VII clotting activity, plasminogen activator inhibitor (PAI-1) and viscosity of blood and plasma. Low density lipoprotein (LDL) promotes platelet activation and tissue factor expression and LDL levels correlate with levels of vitamin K dependent coagulation factors and fibrinogen. Conversely, LDL inhibits tissue factor pathway inhibitor (TFPI) which limits activation of the extrinsic coagulation pathway. High density lipoprotein (HDL) has anti-atherothrombotic properties that result from inhibition of platelet and erythrocyte aggregation, reduced blood viscosity and suppression of tissue factor activity and PAI-1 activity and antigen levels. The effects of lipids and lipoproteins on hemostasis and rheology may have important implications for the clinical sequelae following plaque disruption and erosion.

Plasma fibrinogen of black South Africans: the BRISK study

OBJECTIVE

To describe the distribution of plasma fibrinogen and relationships with other risk factors for coronary heart disease (CHD) and stroke in the black population of the Cape Peninsula.

DESIGN

A cross-sectional survey of a stratified proportional sample of randomly selected black men and women.

SETTING

Households in Gugulethu, Langa, Nyanga, New Crossroads, KTC, Old Crossroads and Khayelitsha in the Cape Peninsula, South Africa.

SUBJECTS

One subject per household (352 men and 447 women), aged 15-64 years, voluntarily participated. Visitors, pregnant, lactating, ill, mentally retarded and intoxicated subjects were excluded.

RESULTS

Mean fibrinogen (thrombin time coagulation method) of men and women were higher than published data for Europeans but slightly lower than values of black Americans. Women aged 45-54 years had the highest level (3.13+/-0.89 g l(-1)) and men aged 15-24 years had the lowest (2.13+/-0.88 g l(-1)). Fifteen per cent of the men and 12% of the women had a level greater than 1 standard deviation of the mean for their age group. Univariate and multivariate analyses revealed significant (P<0.05) positive correlations of fibrinogen with smoking habit, age, body mass index (BMI), total and low-density lipoprotein (LDL) cholesterol, triglycerides, blood pressure and white blood cell count, and significant negative correlations with high-density lipoprotein (HDL) cholesterol, gamma glutamyl transferase (GGT), serum iron and ferritin. The correlations with BMI, serum lipoproteins, iron, ferritin, and GGT suggest that nutritional status and therefore diet influences plasma fibrinogen.

CONCLUSION

Relatively high fibrinogen levels, tending to cluster with other, including diet-related, risk factors for CHD and stroke, were observed in black South Africans. It is suggested that fibrinogen may contribute to the high stroke incidence of this population group.

Association of factor VII protein concentration with lifestyle factors

Several studies have demonstrated that changes in fasting levels of factor VII coagulant activity (FVII:C), a thrombotic risk marker, are due to changes in FVII protein concentrations (FVII:Ag). Consequently, studies on FVII now often include measurements of FVII:Ag. The present cross-sectional study examined the association between several behavioural variables (body mass index, physical activity, tobacco or alcohol consumption) or physiological variables (total cholesterol, HDL-cholesterol, triglycerides, glucose, insulin, fibrinogen, resting pulse, systolic blood pressure, bleeding time) and FVII:Ag in 439 51-y-old Danish men. In the multivariate analyses, body mass index (BMI), low physical activity, total cholesterol, short bleeding time, and insulin showed an independent positive association with FVII:Ag. The strongest independent association with FVII:Ag was found for total cholesterol. These results suggest that blood lipids are major determinants of FVII:Ag, but that other lifestyle factors such as insulin, BMI and physical activity can also influence FVII:Ag. Furthermore, the association between FVII:Ag and bleeding time suggests an effect of FVII or the FVII pathway on primary haemostasis.

Relationship of blood coagulation and fibrinolysis to vital exhaustion

OBJECTIVE

Acute physical and psychological stressors affect blood coagulation and fibrinolysis, but little is known about hemostatic factors associated with chronic psychological stress. Prolonged psychological stress may end in a state of vital exhaustion, which has been shown to be a risk factor for first myocardial infarction and recurrent events after coronary angioplasty. The present study tested the hypothesis that vital exhaustion resulting from chronic psychological stress is associated with impaired fibrinolytic capacity and increased coagulation factors.

METHODS

On the basis of a validated questionnaire and subsequent structured interview, a well-defined group of otherwise healthy exhausted men was recruited (N = 15) and compared with age-matched not-exhausted controls (N = 15). Fibrinolytic measures included tissue plasminogen activator (TPA) antigen and plasminogen activator inhibitor (PAI-1) activity, and as coagulation factors we examined factors VIIc, factor VIIIc, and fibrinogen. Control variables were: blood pressure, smoking status, triglycerides, cholesterol, and standard hematological measures. Samples were collected twice to correct for intraindividual fluctuations. Statistical analyses were performed using 2 x 2 mixed model analysis of variance with subsequent univariate testing.

RESULTS

Vital exhaustion was associated with significantly elevated levels of PAI-1 activity (p = .023). The higher PAI-1 activity in exhausted subjects (median = 13.0 U/ml vs. 6.0 U/ml) was not accounted for by smoking status or serum lipids. No significant differences were observed in TPA antigen, factor VIIc, factor VIIIc, and fibrinogen. The groups did not differ in blood pressure, smoking status, triglycerides, cholesterol, or standard hematological measures.

CONCLUSION

These data suggest a reduced fibrinolytic capacity in exhausted individuals. Therefore, the relationship between vital exhaustion and risk of myocardial infarction may be mediated in part by an imbalance between blood coagulation and fibrinolysis.

Fibrinogen and cardiovascular risk

The hypothesis that fibrinogen is closely related to cardiovascular risk has been strengthened through the results of various lines of research, which this review will aim to unravel. Several prospective epidemiological studies convincingly show elevated fibrinogen to represent a major, independent cardiovascular risk factor. Cross-sectional studies strongly associate fibrinogen and conventional cardiovascular risk factors. Clinical cohort studies demonstrate that increased fibrinogen is also a risk factor for the sequelae of cardiovascular disease. Our knowledge about the determinants of the variable plasma level of fibrinogen in health and disease is incomplete. Understanding of the mechanisms that might be involved in the atherothrombogenic action of fibrinogen is also fragmentary. Fibrinogen strongly affects blood coagulation, blood rheology and platelet aggregation. In addition, it has direct effects on the vascular wall and is a prominent acute phase reactant. All of these phenomena might constitute pathophysiological mechanisms involved in the association between fibrinogen and cardiovascular events. Their relative importance is unclear at present. Even though many crucial questions await conclusive answers, little doubt exists that fibrinogen represents a major, independent risk factor.

Acute and chronic psychological risk factors for coronary syndromes: moderating effects of coronary artery disease severity

This article provides a selective review of the effects of psychosocial factors and responses to acute mental stress on the onset of acute coronary syndromes. The literature suggests that the relationship between the anatomical severity of coronary artery disease (CAD) and likelihood of subsequent cardiac events, such as myocardial infarction, is not linear. Furthermore, evidence will be provided that the age-dependent associations between psychosocial factors and risk of cardiac events is at least in part mediated through the severity of underlying CAD. Finally, research will be summarized that supports the importance of both chronic psychosocial factors (e.g., low socioeconomic status and/or high hostility) and episodic psychological distress syndromes, such as vital exhaustion and depression. In reviewing this literature, two perspectives will be focused on: (1) the relationship between psychosocial factors and progressive CAD; and (2) the evidence concerning underlying pathophysiological mechanisms.