Hemostatic factors and the risk of myocardial infarction or sudden death in patients with angina pectoris. European Concerted Action on Thrombosis and Disabilities Angina Pectoris Study Group

Inflammation, aspirin, and the risk of cardiovascular disease in apparently healthy men

BACKGROUND

Inflammation may be important in the pathogenesis of atherothrombosis. We studied whether inflammation increases the risk of a first thrombotic event and whether treatment with aspirin decreases the risk.

METHODS

We measured plasma C-reactive protein, a marker for systemic inflammation, in 543 apparently healthy men participating in the Physicians' Health Study in whom myocardial infarction, stroke, or venous thrombosis subsequently developed, and in 543 study participants who did not report vascular disease during a follow-up period exceeding eight years. Subjects were randomly assigned to receive aspirin or placebo at the beginning of the trial.

RESULTS

Base-line plasma C-reactive protein concentrations were higher among men who went on to have myocardial infarction (1.51 vs. 1.13 mg per liter, P<0.001) or ischemic stroke (1.38 vs. 1.13 mg per liter, P=0.02), but not venous thrombosis (1.26 vs. 1.13 mg per liter, P=0.34), than among men without vascular events. The men in the quartile with the highest levels of C-reactive protein values had three times the risk of myocardial infarction (relative risk, 2.9; P<0.001) and two times the risk of ischemic stroke (relative risk, 1.9; P=0.02) of the men in the lowest quartile. Risks were stable over long periods, were not modified by smoking, and were independent of other lipid-related and non-lipid-related risk factors. The use of aspirin was associated with significant reductions in the risk of myocardial infarction (55.7 percent reduction, P=0.02) among men in the highest quartile but with only small, nonsignificant reductions among those in the lowest quartile (13.9 percent, P=0.77).

CONCLUSIONS

The base-line plasma concentration of C-reactive protein predicts the risk of future myocardial infarction and stroke. Moreover, the reduction associated with the use of aspirin in the risk of a first myocardial infarction appears to be directly related to the level of C-reactive protein, raising the possibility that antiinflammatory agents may have clinical benefits in preventing cardiovascular disease.

Low-level increases in serum C-reactive protein are present in early osteoarthritis of the knee and predict progressive disease

OBJECTIVE

To examine the role of low-grade inflammation in the etiology and progression of early osteoarthritis (OA) of the knee.

METHODS

We used a new, high-sensitivity, automated monoclonal antibody immunoassay for the classic acute-phase protein, C-reactive protein (CRP), in serum. Anteroposterior radiographs of the knee with weight bearing were obtained on 845 women (ages 44-67) on entry into a population-based study of OA in Chingford, North London. In those defined radiologically as "cases," the knee radiographs were repeated after 4 years.

RESULTS

Levels of CRP were higher in 105 women with knee OA defined radiologically as Kellgren-Lawrence grade 2+ (median 2.4 mg/liter, interquartile range [IQR] 1.0-5.1), compared with 740 women without OA (median 0.7 mg/liter, IQR 0.3-1.8) (P < 0.001). Median levels of CRP were higher in the 31 women whose disease progressed at least 1 Kellgren-Lawrence grade (median 2.6 mg/liter, IQR 1.9-4.6), compared with the 39 whose disease did not (median 1.3 mg/liter, IQR 0.6-2.4) (P = 0.006) . The significance of these differences persisted after adjustment for age, weight, height, smoking, knee pain, or injury. Classifying disease by the presence of joint space narrowing or osteophytes alone produced similar results.

CONCLUSION

CRP levels are modestly but significantly increased in women with early knee OA, and higher levels predict those whose disease will progress over 4 years, suggesting that low-grade inflammation may be a significant aspect of early OA and may be amenable to therapeutic intervention and secondary prevention.

Increased levels of tissue plasminogen activator antigen in essential hypertension. A population-based study in Sweden

OBJECTIVE

To investigate components of the haemostatic and fibrinolytic system in borderline hypertensives and hypertensives, drug-treated or not, from a defined population.

DESIGN AND METHODS

A randomly selected sample of the population of northern Sweden, 1558 subjects aged 25-64 years, was studied. Eight per cent of them were being treated with antihypertensive drugs (trHT). Remaining subjects were classified according to their mean diastolic blood pressure (DBP). Normotension, DBP < 85 mmHg, was found in 63%, borderline hypertension (bHT), DBP 85-94 mmHg, in 21% and untreated hypertension (uHT), DBP > or = 95 mmHg, in 8% of the subjects.

RESULTS

Mean age increased from the normotensive group through the bHT and uHT groups to the trHT group, members of which were the oldest. Age-adjusted values for the body mass index, waist: hip ratio, serum triglyceride and Phadeseph plasma insulin levels increased with each level of hypertension. Plasma fibrinogen levels and plasminogen activator inhibitor type 1 activity (in men) increased stepwise from normotensives through bHT and uHT to the highest values found in the trHT group. The tissue plasminogen activator (tPA) activity in men declined strongly across the groups, trHT having the lowest fibrinolytic activity (P < 0.001). tPA antigen levels increased strongly from normotensives through bHT to uHT, but then were lower in the trHT group. Even after adjustment for possible confounders, men in the uHT group had 21% higher (P = 0.027) tPA antigen levels than did the normotensives. In bHT men, the tPA antigen and plasminogen activator inhibitor type 1 activities were 14 and 24% respectively, higher (P < 0.01) than those in the normotensives.

CONCLUSION

Hypertension is associated with multiple metabolic and fibrinolytic disturbances that are accentuated in drug-treated hypertensives and already discernible in subjects with borderline hypertension. Decreased fibrinolysis is associated with, and possibly secondary to, metabolic disturbances linked to the insulin-resistance syndrome. The independent increase in tPA antigen in hypertensive men might indicate an endothelial dysfunction.

Ten-year follow-up results from the Goettingen Risk, Incidence and Prevalence Study (GRIPS). I. Risk factors for myocardial infarction in a cohort of 5790 men

Besides the accepted major risk factors for myocardial infarction (MI), cholesterol, hypertension and smoking, several other variables such as lipoproteins, apolipoproteins, fibrinogen and family history of MI, have been considered, but their usefulness as predictors of MI is controversially discussed. The Göttingen Risk Incidence and Prevalence Study (GRIPS) aimed to evaluate the independent impact of the latter in comparison to the established risk factors. GRIPS is a prospective cohort study, which included 5790 men, aged 40-59.9 years, without cardiovascular disease at baseline. Multivariate logistic regression models for the estimation of the MI risk based on the 10-year follow-up data from 97.4% of the study participants established LDL cholesterol as the strongest predictor of MI. It was followed by family history of MI, Lp(a), age, smoking, systolic blood pressure, HDL cholesterol (inversely related) and plasma glucose (P < 0.001). Apolipoprotein B as well as the ratios total/HDL cholesterol, LDL/HDL cholesterol and Apo B/AI were less effective predictors than LDL cholesterol and did not contribute independently to the estimation of MI risk. Similarly apoprotein AI was a weaker predictor of MI risk then HDL cholesterol. GRIPS is the first prospective cohort study which clearly justifies the key role of LDL cholesterol in preventive strategies. However, the data also give strong support for the additional consideration of other risk factors for a valid estimation of the MI risk for an individual subject.

The renin-angiotensin system and fibrinolysis

In addition to causing vasoconstriction and the retention of salt and water, angiotensin inhibits fibrinolysis, thereby promoting clot formation and protecting against hemorrhage. Activation of the renin-angiotensin system (RAS) can disturb the balance of the fibrinolytic system by stimulating excess production of plasminogen activator inhibitor type 1 (PAI-1) and increasing the risk of thrombotic events. This risk is exacerbated by angiotensin-converting enzyme (ACE)-induced degradation of bradykinin, which normally stimulates production of tissue-type plasminogen activator (t-PA). Modification of the RAS via ACE inhibition may protect against thrombosis by limiting vascular expression of PAI-1 and augmenting bradykinin-induced production of t-PA. Survivors of myocardial infarction treated with an ACE inhibitor have demonstrated a reduction in PAI-1 activity and preservation of the normal ratio of PAI-1 to t-PA. This effect on the fibrinolytic system may contribute to the favorable impact ACE inhibition has been demonstrated to have on the incidence of recurrent myocardial infarction.

Gender-specific associations of the fibrinogen B beta 448 polymorphism, fibrinogen levels, and acute cerebrovascular disease

Fibrinogen is an independent risk factor for the development of stroke. Factors influencing circulating levels of fibrinogen include age, smoking, gender, and genetic factors. The aim of this study was to determine the relationship between a polymorphism at position 448 of the B beta fibrinogen gene, fibrinogen levels, gender, and the risk of stroke. Fibrinogen levels were determined in 305 patients with stroke, taken within 10 days of the acute event and 3 months later, and in 197 control subjects. Initial fibrinogen levels in patients (4.49 g/L) were significantly higher than at 3 months (3.85 g/L, P < .0001), consistent with resolution of the acute-phase response. At 3 months, levels were only significantly higher than for control subjects in the male patients (3.86 g/L versus 3.31 g/L, P < .0001). Fibrinogen levels were associated with B beta 448 genotype in male patients at 3 months (1/1 = 3.62 g/L, 1/2 + 2/2 = 4.27 g/L, P = .01). There was a significant difference in the genotype distribution in female patients and control subjects (patients: 1/1 = 95, 1/2 = 34, 2/2 = 6; control subjects: 1/1 = 61, 1/2 = 50, 2/2 = 3, P = .008). These data suggest that the mechanisms linking fibrinogen and the development of cerebrovascular disease are different in males and females. In male patients, the increase in fibrinogen levels may be influenced by environmental factors, while in females there may be a functional difference in the fibrinogen molecule unrelated to fibrinogen levels.

Hypobetalipoproteinemia is associated with low levels of hemostatic risk factors in the Framingham offspring population

BACKGROUND

Given the importance of thrombosis in causation of acute coronary syndromes, it is possible that the beneficial effect of low lipid levels on the risk of coronary events is achieved by lowering thrombotic potential of the blood. Hypobetalipoproteinemia is characterized by plasma concentrations of apolipoprotein B and LDL cholesterol that are one third of those observed in the general population. The aim of this study was to utilize subjects with hypobetalipoproteinemia to examine the relation between thrombotic potential and low levels of LDL cholesterol.

METHODS AND RESULTS

Hemostatic risk factors were measured in 1878 individuals (1003 women and 875 men) participating in cycle 5 of the Framingham Offspring Study. The subjects were divided into five groups on the basis of LDL cholesterol level. Subjects with hypobetalipoproteinemia (LDL cholesterol < 70 mg/dL) had the lowest levels of fibrinogen, plasminogen activator inhibitor-1 antigen, and tissue plasminogen activator antigen. As LDL cholesterol increased, there was a significant increase in the levels of the hemostatic risk factors, with the exception of von Willebrand factor antigen. Adjustment with multivariate regression analyses for the covariates age, sex, body mass index, diabetes mellitus, smoking, alcohol intake, triglyceride level, and use of antihypertensive medication did not materially alter the results.

CONCLUSIONS

Decreasing levels of LDL cholesterol are associated with decreasing levels of hemostatic risk factors. Subjects with hypobetalipoproteinemia have the lowest levels of hemostatic risk factors and may be protected against thrombotic complications of atherosclerotic cardiovascular disease because of reduced thrombotic potential. One mechanism by which lipid-lowering therapy may decrease clinical cardiac events is through a reduction in thrombotic tendency.

Production of C-reactive protein and risk of coronary events in stable and unstable angina. European Concerted Action on Thrombosis and Disabilities Angina Pectoris Study Group

BACKGROUND

Inflammation is an important feature of atherosclerotic lesions, and increased production of the acute-phase reactant. C-reactive protein (CRF), is associated with a poor prognosis in severe unstable angina. We have investigated the existence and possible significance of the acute-phase responses of CRP and another sensitive reactant, serum amyloid A protein (SAA), in patients with unstable or stable angina.

METHODS

We used new ultrasensitive immunoassays to measure CRP and SAA concentrations in plasma from 2121 outpatients with angina (1030 unstable, 743 stable, the rest atypical) enrolled in the European Concerted Action on Thrombosis and Disabilities (ECAT) Angina Pectoris Study. All patients underwent coronary angiography and extensive clinical and laboratory assessment at study entry, and were then followed up for 2 years. All suspected coronary events during follow-up were reviewed by an independent endpoint committee.

FINDINGS

75 individuals (41 with unstable, 29 with stable, and 5 with atypical angina) had a coronary event during follow-up. Concentrations of CRP at study entry were associated with coronary events in patients with stable or unstable angina: there was about a two-fold increase in the risk of a coronary event in patients whose CRP concentration was in the fifth quintile (> 3.6 mg/L), compared with the first four quintiles. A third of the events occurred among patients who had a CRP concentration of more than 3.6 mg/L. CRP concentrations were positively correlated with age, smoking, body-mass index, triglycerides, extent of coronary stenosis, history of myocardial infarction, and lower ejection fraction. By contrast, concentrations of SAA were not associated with risk of a coronary event.

INTERPRETATION

We found that raised circulating concentrations of CRP are predictors of coronary events in patients with stable or unstable angina. The modest acute-phase responses of CRP were probably not the result of myocardial necrosis. Whatever the underlying mechanisms, the sensitive measurement of CRP as a prognostic marker may be useful in the management of coronary heart disease.

[Cardiovascular risk factors in diabetic nephropathy]

BACKGROUND

Diabetic nephropathy is associated with increased cardiovascular mortality. This may be contributed to by changes in plasma lipids, fibrinogen and hemorheology. Cardiovascular autonomic dysfunction, which is related to an increased incidence of arrhythmic death, may also play a role.

PATIENTS AND METHODS

Therefore, we investigated in 58 IDDM-patients with none (n = 28), incipient (albuminuria 30 to 300 mg/day, n = 11) and overt clinical nephropathy (albuminuria > 300 mg/day, n = 19) plasma concentrations of lipoproteins and fibrinogen, plasma viscosity, erythrocyte aggregation and erythrocyte rigidity. Assessments of neuropathy included tibial nerve motor conduction velocity, perception of vibration, beat-to-beat variation during rest and during forced respiration, heart-rate response to Valsalva maneuver and heart-rate response to standing (30:15).

RESULTS

Patients with clinical overt nephropathy had, compared to those without nephropathy, significantly higher concentrations of LDL-cholesterol, triglycerides and fibrinogen, significantly lower concentrations of HDL-cholesterol and significantly higher plasma viscosity, erythrocyte aggregability and erythrocyte rigidity. Regarding the assessments of neuropathy we found in patients with nephropathy, compared to those without nephropathy, significantly reduced tibial nerve motor conduction velocity, reduced perception of vibration thresholds and reduced heart rate variability during rest, during forced respiration, in response to Valsalva maneuver and in response to standing. In diabetic patients with microalbuminuria erythrocyte aggregability and erythrocyte rigidity were significantly higher and heart rate variability during rest was significantly lower than in patients without nephropathy.

CONCLUSION

In clinical overt nephropathy there is an aggregation of different cardiovascular risk factors, namely, disturbances in lipoprotein concentrations, increased fibrinogen concentration and disturbances in hemorheology. Furthermore marked deterioration in peripheral and autonomic cardial nerve function in these patients is evident accounting for a part of the greatly increased cardiovascular mortality of these patients.

Effect of endurance training and seasonal fluctuation on coagulation and fibrinolysis in young sedentary men

The effect of 12 wk of submaximal training on hemostatic variables was studied in 20 young sedentary men (Tr) and 19 nontraining matched controls (Con). After training, a more pronounced increase in factor VIII coagulant activity (P < 0.01), reflected in a decrease in activated partial thromboplastin time (P < 0.01) during maximal exercise, was seen. Both basal plasminogen activator inhibitor 1 antigen (PAI-1 Ag) and activity (PAI-1 Act; P < 0.05), as well as basal and exercise-induced tissue-type plasminogen activator antigen (t-PA Ag; P < 0.05), were decreased after training. The overall effect on fibrinolysis was reflected in an increase in the t-PA Act/t-PA Ag ratio in the Tr group. In contrast, during the same period (February-June), the Con group demonstrated an increase in basal PAI-1 Ag and PAI-1 Act (P < 0.05), together with an increase in basal and exercise-induced t-PA Ag (P < 0.05). Both basal and exercise-induced t-PA Act were unchanged, but t-PA Act/t-PA Ag was decreased (P < 0.05) in the Con group. We conclude that physical training promotes both coagulation and fibrinolytic potential during exercise and may reverse unfavorable seasonal effects on fibrinolysis.

Arterial and venous thrombosis is not associated with the 4G/5G polymorphism in the promoter of the plasminogen activator inhibitor gene in a large cohort of US men

BACKGROUND

The 4G allele of the 4G/5G polymorphism in the promoter of the plasminogen activator inhibitor (PAI-1) gene is associated with increased PAI-1 activity. In a small group of young Swedish men, this allele has been reported to predict risk of myocardial infarction. Whether this polymorphism increases risk of arterial and venous thrombosis among middle-aged men is unknown.

METHODS AND RESULTS

Among 14916 men 40 to 84 years old participating in the Physicians' Health Study who provided baseline blood samples for DNA analysis, 374 suffered first myocardial infarction and 121 had venous thromboembolism during 8.6 years of follow-up. Distributions of the 4G/5G polymorphism in the PAI-1 gene promoter were assessed in these men as well as in a sample of study participants matched on age and smoking who did not develop vascular occlusion during the prospective follow-up period. The distributions of the 4G/4G, 4G/5G, and 5G/5G genotypes among men who developed myocardial infarction (0.27, 0.51, 0.22; P = .7) or venous thromboembolism (0.30, 0.49, 0.21; P = .5) were virtually identical to those of men who remained free of vascular disease (0.27, 0.50, 0.23). Thus, the relative risk of future thrombosis among those with the 4G/4G genotype compared with those without the 4G/4G genotype was 1.02 (95% CI, 0.8 to 1.3). There was no effect modification by age, smoking status, family history of premature thrombosis, history of hypertension, hypercholesterolemia, or aspirin use.

CONCLUSIONS

These data indicate that the 4G/5G polymorphism in the promoter of the PAI-1 gene is not a major pathogenetic risk factor for arterial or venous thrombosis among middle-aged men.

Variability in the measurement of C-reactive protein in healthy subjects: implications for reference intervals and epidemiological applications

We developed a reproducible ELISA for C-reactive protein (CRP), calibrated with WHO Reference Material, for which intra- and interassay CVs were 3.0% and 6.0%, respectively. Analytical recovery was 97.9%. The distribution of CRP in a healthy blood donor population (n = 143) was nongaussian, with 2.5th, 50th, and 97.5th percentile values of 0.08, 0.64, and 3.11 mg/L, respectively. There was no sex-related difference, and the association with age was weak. In a study of variability [by the method of Fraser and Harris (Crit Rev Clin Lab Sci 1989;27:409–37)], the analytical variability was 5.2%; the within-subject variability, CVI, was 42.2%; and the between-subject variability, CVG, was 92.5%. The critical difference for sequential values significant at P ≤0.05 (i.e., the smallest percentage change unlikely to be due to analytical variability or CVI) was calculated as 118%, and the index of individuality, CVI/CVG, was 0.46. This suggests that CRP, like many clinical chemistry analytes, has limited usefulness in detecting early disease-associated changes when used in conjunction with a healthy reference interval. From a molecular epidemiological standpoint, the usefulness of CRP in longitudinal studies is suggested by the small index of individuality and by observations that (a) short-term fluctuations were infrequent, (b) all data stayed within the reference interval, and (c) relative rankings of the subjects over 6 months only moderately deteriorated.

Fibrinogen and its relations to subclinical extracoronary and coronary atherosclerosis in hypercholesterolemic men

The association between plasma fibrinogen and the presence of carotid, femoral, and aortic plaque (high-resolution B-mode ultrasonography) and coronary calcium deposit (ultrafast computed tomography scanner) was determined in 693 hypercholesterolemic, never-treated men free of previous or current clinical symptoms of cardiovascular disease. The number of subjects with extracoronary disease sites and coronary calcification deposits was significantly higher in the upper than in the lower tertile of fibrinogen. Plasma fibrinogen increased according to the number of diseased sites. The odds ratio of the upper to lower fibrinogen tertile for the presence of arterial lesions was 2.6 (1.7 to 4) for carotid, 2.2 (1.5 to 3.2) for aorta, 2.2 (1.5 to 3.1) for femoral, 1.8 (1.3 to 2.6) for coronary, and 3.6 (2.3 to 6.1) for one of four diseased sites. Adjustment for age, total cholesterol, HDL cholesterol, triglycerides, current smoking, and systolic pressure slightly reduced the association between fibrinogen and atherosclerosis. A synergistic effect between fibrinogen and total cholesterol/ HDL cholesterol (TC/HDL) ratio seemed to be operating on atherosclerosis, because nearly all of the individuals (98%) had a diseased site when fibrinogen and TC/HDL tertiles were the highest. This result suggests that fibrinogen is involved in the subclinical phase of extracoronary and coronary atherosclerosis and may potentiate the atherogenic effect of hyperlipidemia.

Plasma protein C inhibitor is elevated in survivors of myocardial infarction

Many studies have shown alterations of the hemostatic and fibrinolytic systems in patients with atherosclerotic disease, principally in levels of plasminogen activator inhibitor-1. However, in a large prospective study only fibrinogen, von Willebrand factor antigen, and tissue plasminogen activator antigen were found to be independent risk markers for acute coronary events. The present study evaluated the fibrinolytic system in coronary artery disease, paying particular attention to another inhibitor of fibrinolysis, plasminogen activator inhibitor-3, also called protein C inhibitor (PCI). One hundred fifteen nonanticoagulated male survivors of myocardial infarction were investigated for a range of hemostatic and fibrinolytic parameters that were compared with values in 87 age-matched healthy control male subjects. PCI active antigen was significantly (P < .03) elevated in the myocardial infarction group compared with the control group and was associated with the number of acute coronary events suffered (P = .005) but not with the severity of disease as determined by coronary angiography. Elevated PCI plasma levels can be considered as a risk marker for acute coronary events and might be of particular importance in the pathogenesis of this disease due to the interference of PCI in both the anticoagulant and fibrinolytic systems.

Hemostatic variables and ischemic cardiovascular disease: do we need a concerted effort for more profitable future clinical investigations?

Abnormally high levels of some hemostatic variables are often associated with the occurrence of the major ischemic complications of atherosclerosis, myocardial infarction, and stroke. Intervention studies have shown that prolonged treatment with antiplatelet drugs significantly reduces the recurrence of coronary and cerebral ischemic episodes. The association of the ischemic event with the hemostatic abnormality has often been just descriptive. Although suggestive, the link between the abnormality and the development and progression of atherosclerosis is only circumstantial. Finally, no information is available on the presence of one or more abnormal variables in subjects who did or did not experience a recurrence of thrombosis with treatment. To strengthen the clinical relevance of these hemostatic variables and to maximize the effectiveness of antithrombotic strategies, these indices should be taken into account in studies evaluating nonpharmacological and pharmacological interventions against arterial thrombosis. We believe that a task force on this subject would serve a useful purpose. The task force should develop and publicize within the cardiological community guidelines for (a) defining the size of the problem, (b) identifying the variables to measure, (c) standardizing detection and monitoring techniques, and (d) suggesting appropriate strategies of prevention and treatment.

The risk and cost-effective individual patient management: the challenge of a new generation of clinical trials

The percentage reduction of risk demonstrated in several recent trials in quite remarkable. For example 1 out of 5, and even as many as 1 out of 3, fatal cardiovascular events can be prevented by some treatments. Further efforts aimed at producing a substantially greater percentage reduction of risk than demonstrated so far with thrombolytic agents in acute MI, aspirin in patients discharged from the hospital with a diagnosis of unstable angina, or statins in the secondary and primary prevention of ischemic heart disease would be quite difficult to achieve and would require greater patient compliance and more powerful drugs, possibly with greater side effects and costs. The growing size of trials with very broad inclusion criteria may seem logical to "trialists," who reason that the broader the inclusion criteria, the easier it is recruit very large numbers of patients in a short space of time and the more widely applicable the results of the study. The pharmaceutical industry also prefers broad inclusion criteria, which imply wider indications for use of their products. However, very large trials with broad inclusion criteria raise two grounds for concern for practicing physicians and for the economics of health care. The first is the fact that the larger the number of patients that have to be included in a trial in order to prove a statistically significant benefit, the greater the uncertainty about the reason why the beneficial effects of the treatment cannot be detected in a smaller trial. Secondly, this method of assessment is rapidly increasing the number of treatments that produce a statistically significant improvement in prognosis within the same broad group of patients. A large percentage reduction in mortality that reaches statistical significance only in very large trials suggests either a relatively low rate of preventable deaths in all individuals in the group or considerable heterogeneity in the patients enrolled, only a few of whom benefit from the treatment. This alternative is of considerable practical importance, first because a large heterogeneity of patients implies a "dilution effect" of those susceptible to the benefits of treatment by those who are not susceptible and are treated unnecessarily, and second, because uniformly low rates of potentially preventable death rise such issues as prolongation of life expectancy, surrogate endpoints, and the effects of treatment on the quality of life. Only a new generation of clinical trials that include only homogenous groups of potential responders can produce both results more readily applicable to personalized patient care in clinical practice (which is a desirable target for the practicing physician) and a large reduction in the number of events per patient treated (which is a desirable target for the economics of health care.

Antithrombotic treatment in stable coronary syndromes: long-term intermittent urokinase therapy in end-stage coronary artery disease and refractory angina pectoris

Interventions that modify lipid metabolism and blood coagulation have been shown to favourably influence the natural course of coronary artery disease in terms of the primary prevention and treatment of acute cardiovascular events. Various findings suggest that such interventions may also preserve and enhance myocardial perfusion in the chronic stage of the disease. Long-term intermittent urokinase therapy was developed for patients with end-stage coronary artery disease and refractory angina pectoris. A dose of 500,000 IU of urokinase given intravenously as a bolus three times a week for of 12 weeks reduced symptoms by 70% and was accompanied by objective improvements in myocardial perfusion and an increase of ergometric exercise capacity. The possible therapeutic mechanisms of long-term intermittent urokinase therapy-improvement of rheological blood properties mediated by fibrinogen reduction, thrombolysis of non-occlusive subclinical thrombi, and regression of atherosclerotic plaques-are discussed in the context of other antithrombotic approaches.

Changes in hemostatic function at times of cyclic variation in occupational stress

In this study we demonstrated, in the same healthy subjects, a significant elevation in coagulation factors VII and VIII, fibrinogen, thrombocyte count, and thrombin and adenosine diphosphate-induced platelet aggregation during a period of increased workload compared with a calm work period. These findings may add to the understanding of the mechanism that links mental stress to coronary disease.

Aortic atherosclerosis and stroke

METHODS

Studies using transesophageal echocardiography (TEE) suggest aortic atherosclerosis may be a risk factor for stroke, particularly stroke of undetermined mechanism, but controls in prior studies were not balanced for vascular risk factors. We used TEE to evaluate aortic atherosclerosis in 60 patients with stroke compared with a high-risk control population of 46 subjects. We also examined the possible association of plasma viscosity and fibrinogen levels to aortic atherosclerosis.

RESULTS

The mean maximal plaque thickness (MMPT) was similar for the control (2.8 +/- 3.6 mm) and the stroke group (3.3 +/- 3.5 mm), but varied with stroke mechanism. The MMPT was similar in stroke of undetermined and atherosclerotic mechanism [3.5 +/- 4 mm (n = 25) and 4.2 +/- 4.3 mm (n = 16), respectively], significantly greater than in stroke of other mechanisms (1.7 +/- 1.2 mm, P < .05, n = 19). Patients with stroke of undetermined mechanism were four times more likely (95% confidence interval [CI] 1.2-12) to have plaques >/=5 mm compared with controls. Ulcerated plaque was associated with plaque thickness (P < .001) and plasma viscosity (P < .001).

CONCLUSIONS

Aortic atherosclerosis is associated with stroke of undetermined cause suggesting atherosclerosis is a cause of stroke of undetermined etiology. Plaque ulceration was associated with the thickness of aortic plaque and plasma viscosity.

Associations between carotid atherosclerosis and high factor VIII activity, dyslipidemia, and hypertension

BACKGROUND AND PURPOSE

A subsample of 147 Chinese subjects from a population-based study of cardiovascular diseases (Cardiovascular Disease Risk Factor Two-Township Study) participated in an ancillary study on extracranial carotid color duplex ultrasonography that aimed to assess the relations of coagulation factors to stroke and carotid atherosclerosis.

METHODS

Logistic models were used to study the associations between cardiovascular disease risk factors and stroke/carotid atherosclerosis, controlling for the effects of age and sex.

RESULTS

Stroke was significantly associated with hypertension and high values of plasma glucose but not with fibrinogen, factor VIIc, or factor VIIIc. Carotid plaques identified in this study were mostly mild and moderate. The presence of these mild and moderate carotid plaques was significantly associated with high values of factor VIII activity, hypercholesterolemia, hypertriglyceridemia, and hypertension. The highest tertile of factor VIIIc (> 1.53) was associated with an odds ratio of 3.35 for carotid atherosclerosis when compared with the lowest tertile (< 1.20). A multiple logistic regression including all significant risk factors showed that the degree of association between factor VIIIc and atherosclerosis was attenuated to an odds ratio of 2.65 (P = .061).

CONCLUSIONS

In the present study, the roles of hypertension, hypercholesterolemia, and hypertriglyceridemia have been implicated in the pathogenesis of carotid atherosclerosis, and roles for hypertension and hyperglycemia in stroke were indicated. A positive association between factor VIIIc and carotid atherosclerosis in this Chinese population was found. Whether this association is independent of the effect of other cardiovascular risk factors awaits further study.

The pathogenesis and prevention of atherosclerosis

Most measures taken to prevent atherosclerosis still aim at lowering the cholesterol content of the plasma lipoproteins by dietary and pharmacological means. This approach has only proved successful to a limited extent. Diseases secondary to atherosclerosis are still the commonest cause of death in western industrialized countries. As all metabolic processes are regulated by opposing processes of equilibrium, i.e. by processes directed towards performance and recovery, we asked ourselves whether the fatty degeneration and sclerosis of the arteries could be causally related to a continuous dysregulation of these processes. We consider this to be the case, with a continuous deficiency of glycosaminoglycans (heparin, heparinoids) on the endothelial surface of the vessels. Numerous studies indicate that in the case of thinning of the anionic glycosaminoglycan film on the endothelial surface, the lipoprotein-lipase and antithrombin III activity induced by heparin is reduced, as result of which hyperlipoproteinaemia and increased tendency to thrombosis can only by compensated for to an inadequate extent. The formation of glycosaminoglycans is a characteristic of all mesenchymal cells, whereby the exogenous introduction of glycosaminoglycans into the extracellular space is of decisive importance for adequate glycosaminoglycan synthesis. Since Engelberg reported outstanding results obtained with heparin injections in the prevention and treatment of atherosclerotic disorders of the cardiac circulation, we considered it appropriate to use the well-proven dietary supplement of glycosaminoglycans in rheumatology, in the treatment of arthrosis, as well as in the prevention and treatment of atherosclerosis.

Circulating levels of factor VII, fibrinogen, and von Willebrand factor and features of insulin resistance in first-degree relatives of patients with NIDDM

BACKGROUND

First-degree relatives of patients with non-insulin-dependent diabetes mellitus (NIDDM) have an increased risk of coronary artery disease partly attributable to clustering of risk factors in association with insulin resistance. Circulating levels of some hemostatic factors predict coronary events, and there is growing evidence that insulin resistance is also associated with abnormalities of coagulation and fibrinolysis. This study examined the hypotheses that elevated levels of factor VII coagulant activity (FVII:C), fibrinogen, and von Willebrand factor (vWF) occur (1) in first-degree relatives of NIDDM patients and (2) in association with recognized features of insulin resistance.

METHODS AND RESULTS

Fasting blood samples were taken from 132 first-degree relatives of NIDDM patients and 151 age matched control subjects for measurement of FVII:C, fibrinogen, vWF, insulin, total and HDL cholesterol, triglyceride, glucose, and HbAIC. Levels of FVII:C (130% versus 122%, P < .02) and fibrinogen (3.0 versus 2.7 g/L, P = .002) were higher in relatives than in control subjects, and there was no significant difference in levels of vWF (0.98 versus 0.95 IU/mL). There was a graded association with features of insulin resistance, which was strongest for FVII:C, weaker for fibrinogen, and weakest for vWF.

CONCLUSIONS

FVII:C and fibrinogen levels are increased in relatives of patients with NIDDM. Levels of FVII:C and, to a lesser extent, fibrinogen and vWF cluster with other risk factors associated with insulin resistance. Abnormalities of circulating hemostatic factors, possibly in relation to insulin resistance, may contribute to cardiovascular risk in relatives of patients with NIDDM.

Fibrinolytic factors and the risk of myocardial infarction or sudden death in patients with angina pectoris. ECAT Study Group. European Concerted Action on Thrombosis and Disabilities

BACKGROUND

Disturbances of the fibrinolytic system that lead to decreased removal of fibrin deposits may be important risk factors for coronary thrombosis. There is as yet no consensus on the prognostic value of fibrinolytic parameters, which may be attributed in part to the choice of confounding variables controlled for.

METHODS AND RESULTS

The ECAT study is a prospective multicenter study of 3043 patients with angina pectoris followed for 2 years. Baseline measurements included 10 fibrinolytic variables. The results were analyzed in relation to the subsequent incidence of myocardial infarction or sudden coronary death. They are presented before and after adjustment for clusters of confounding variables that are markers of different mechanisms: insulin resistance (body mass index, triglyceride, and HDL cholesterol), inflammation (fibrinogen and C-reactive protein), and endothelial cell damage (von Willebrand factor). An increased incidence of events was associated with higher baseline concentrations of tissue plasminogen activator (TPA) antigen (P = .0002), plasminogen activator inhibitor-1 (PAI-1) activity (P = .02), and PAI-1 antigen (P = .001). The associations of PAI-1 activity and PAI-1 antigen with risk of events disappeared after adjustment for parameters reflecting insulin resistance but were not affected by other adjustments. TPA antigen was affected to a similar extent by adjustment for parameters reflecting insulin resistance. Inflammation, or endothelial cell damage, but the risk association disappeared only after combined adjustments.

CONCLUSIONS

The prognostic role of PAI-1 in predicting coronary events is related principally to insulin resistance, whereas that of TPA antigen could be explained only by its relationship with different mechanisms, including insulin resistance, inflammation and endothelial cell damage.

Effects of n-3 fatty acids and fenofibrate on lipid and hemorrheological parameters in familial dysbetalipoproteinemia and familial hypertriglyceridemia

There is increasing evidence that hemorrheological abnormalities are associated with an enhanced risk of atherosclerosis. The n-3 fatty acids (n-3-FA) have been shown to have beneficial effects on atherosclerosis in patients with dyslipoproteinemias. We studied 23 patients with elevated plasma triglycerides to evaluate the influence of fish oil and fenofibrate therapy on hemorrheological parameters (15 patients with familial hypertriglyceridemia [FHTG] and eight with familial dysbetalipoproteinemia [FDL]). The patients (one woman and 22 men aged 45.7 +/- 2.0 years) were treated with increasing doses of n-3-FA (1.8 to 3.6 g/d: 0.9 to 1.8 g eicosapentaenoic acid and 0.6 to 1.2 g docosahexaenoic acid) for 8 weeks. Lipid parameters, whole-blood viscosity at different shear rates, plasma viscosity, fibrinogen concentration, and red blood cell aggregation (RCA) were measured at baseline and at weeks 2, 4, 8 (end of n-3-FA therapy), and 12. Compliance was ensured by measuring plasma concentrations of eicosapentaenoic acid and docosahexaenoic acid. After 12 weeks, patients began treatment with fenofibrate (250 mg daily); investigations were performed again at week 20. Total triglycerides (from 6.90 +/- 1.70 to 3.61 +/- 0.78 mmol/L in FDL and 7.44 +/- 1.50 to 4.15 +/- 0.55 in FHTG), very-low-density lipoprotein (VLDL) triglycerides, and VLDL cholesterol were significantly decreased with n-3-FA therapy in both groups (P < .05). In FHTG, low-density lipoprotein (LDL) cholesterol increased significantly (from 2.75 +/- 0.28 to 3.97 +/- 0.35 mmol/L, P < .01); in FDL, total cholesterol decreased (from 9.76 +/- 1.32 to 7.34 +/- 1.07 mmol/L, P < .05). No significant changes were observed in hemorrheological parameters, except for reduced RCA with 3.6 g n-3-FA in FHTG. However, with fenofibrate therapy, in addition to comparable lipoprotein changes seen with fish oil, fibrinogen levels and plasma and blood viscosity decreased in patients with FDL. We conclude that n-3-FA and fenofibrate have comparable effects on lipid parameters in patients with FDL and FHTG. Because of additional beneficial effects on hemorrheological parameters, fenofibrate may be preferred for the treatment of FDL.

Urapidil treatment decreases plasma fibrinogen concentration in essential hypertension

The effects of antihypertensive drugs on cardiovascular metabolic risk factors were monitored in 42 patients with essential hypertension (diastolic blood pressure [DBP] >95 mm Hg). In a double-blind randomized parallel-group study, they were treated with atenolol 50 mg once per day (n = 25) or urapidil 60 mg twice per day (n = 17), a peripheral alpha1-receptor blocker with an additional central serotonin 1A (5HT1A) receptor agonistic effect, for 12 weeks. Plasma fibrinogen concentration decreased by 24% (P < .0001) during urapidil treatment and by 9% (P = .05) during atenolol treatment, with the effects of the two drugs differing significantly. Plasminogen activator inhibitor (PAI) activity tended to increase by 17% (nonsignificant [NS]) in the atenolol-treated group and to decrease by 4% (NS) in the urapidil group. Differences between the effects of the two drugs on very-low-density lipoprotein (VLDL) triglycerides (TG) and on total TG were significant. During urapidil medication, these two parameters were reduced by 22% and 13%, respectively, but the changes were nonsignificant (P = .11 and P = .14, respectively). In contrast, atenolol treatment caused a significant increase in both VLDL TG and total TG of 31% and 21%, respectively. Hemoglobin A1c (HbA1c) increased by 4% (P = .06) during atenolol treatment, but was unaffected by urapidil. There were no significant changes within or between atenolol- and urapidil-treated groups regarding glucose disposal on an oral glucose tolerance test (OGTT) or the insulin sensitivity index on a hyperinsulinemic-euglycemic clamp test. In conclusion, urapidil treatment was characterized by neutral or favorable effects on several variables associated with the metabolic syndrome. Atenolol treatment had neutral properties in some metabolic aspects, but deleterious effects on lipid status.

Coagulation and fibrinolytic profiles in patients with severe pulmonary hypertension

STUDY OBJECTIVES

Although in situ thrombosis is a prominent finding in lung vessels from patients with primary and secondary pulmonary hypertension, to our knowledge, plasma coagulation factors that might contribute to a hypercoagulable state have not been fully investigated. We hypothesized that the local coagulation environment in the lung vasculature is important to progression if not initiation of pulmonary hypertension.

DESIGN

Quasi-experimental cross-sectional design with concurrent controls.

SETTING

Referral clinics and inpatient services of a University Hospital and a Veterans Administration Medical Center.

PARTICIPANTS

To investigate the role of plasma coagulation factors in severe pulmonary hypertension, we sampled plasma from patients with primary pulmonary hypertension, patients with pulmonary hypertension secondary to a discernible etiology, and normal adult control subjects.

RESULTS

We detected abnormalities of the thrombomodulin/protein C anticoagulant system, evidenced by a decrease in soluble thrombomodulin, in patients with primary pulmonary hypertension. In the patients with primary pulmonary hypertension, we found impaired fibrinolytic activity, with a rise in the fibrinolytic inhibitor plasminogen activator 1 and elevated euglobulin lysis time. Lower fibrinolytic activity correlated with high mean pulmonary artery pressure. In contrast, in patients with secondary pulmonary hypertension, von Willebrand factor antigen and fibrinogen levels were increased, and fibrinolytic activity decreased.

CONCLUSIONS

Different patterns of coagulation and fibrinolytic abnormalities are apparent in plasma from patients with primary and secondary pulmonary hypertension. Although we are unable to address causality with this study, we speculate that abnormalities of these coagulation mechanisms may initiate or play a role in perpetuation of pulmonary hypertension.

Angiographic severity of coronary narrowing is a surrogate marker for the extent of coronary atherosclerosis

Most acute coronary events occur because of narrowings at sites of angiographically minor plaque. Despite this, angiograms are reported in terms of the number of coronary arteries with severe narrowings. Disease severity is correlated with prognosis, but this may simply be due to a strong positive correlation between the severity and extent of coronary atheroma. We therefore aimed to assess the relation between the severity and the extent of coronary atherosclerosis. Coronary angiograms of 350 consecutive patients referred for elective cardiac catheterization were analyzed. Two independent observers calculated the number of arteries with > or = 70% stenosis, a disease severity score, and an extent score (percentage of the coronary artery length with any luminal irregularity). There were no obstructive stenoses in 123 patients (35%); 91 (26%) had 1-vessel disease, 81 (23%) had 2-vessel disease, and 55 (16%) had 3-vessel coronary artery disease. The median severity score was 1 (lower, upper quartile 0, 3; range 0 to 8), and the median extent score was 66% (lower, upper quartile 32, 83; range 0% to 100%). There was a strong linear relation between severity score and extent score (r = 0.62, p < 0.001); however, the data were better described by 2 intersecting straight lines, with a steeper increase in disease severity when the extent score was between 80% and 90% (F1;121 = 6.9, p = 0.001). The severity of coronary disease is therefore significantly correlated with disease extent. This may explain the observed relation between the number of arteries with obstructive stenoses and subsequent risk, even though most events occur at sites of minor plaque.

Poor oral health and coronary heart disease

A few recent studies have shown associations between poor oral health and coronary heart disease (CHD). The objective of this study was to examine the incidence of CHD in relation to number of teeth present and periodontal disease, and to explore potential mediators of this association, in a prospective cohort study. This study is a part of the ongoing Health Professionals Follow-Up Study (HPFS). Participants included a US national sample of 44,119 male health professionals (58% of whom were dentists), from 40 to 75 years of age, who reported no diagnosed CHD, cancer, or diabetes at baseline. We recorded 757 incident cases of CHD, including fatal and non-fatal myocardial infarction and sudden death, in six years of follow-up. Among men who reported pre-existing periodontal disease, those with 10 or fewer teeth were at increased risk of CHD compared with men with 25 or more teeth (relative risk = 1.67; 95% confidence interval, 1.03 to 2.71), after adjustment for standard CHD risk factors. Among men without pre-existing periodontal disease, no relationship was found (relative risk = 1.11; 95% confidence interval, 0.74 to 1.68). The associations were only slightly attenuated after we controlled for dietary factors. No overall associations were found between periodontal disease and coronary heart disease. Tooth loss may be associated with increased risk of CHD, primarily among those with a positive periodontal disease history; diet was only a small mediator of this association.

Thrombogenic and fibrinolytic factors and cardiovascular risk in non-insulin-dependent diabetes mellitus

Disturbances of the haemostatic system may favour the development of vascular damage and the final occlusion events in the progress of coronary heart disease (CHD). It has been shown recently in epidemiological studies, that increased concentration of several factors, mainly fibrinogen, factor VII, von Willebrand factor (vWF), and the fibrinolytic variables plasminogen activator inhibitor 1 (PAI-1) and tissue plasminogen activator (t-PA), can be considered as risk factors for CHD. As morbidity and mortality through coronary atherosclerosis are higher in type 2 diabetic patients than in nondiabetic subjects and as insulin resistance represents a situation which favours the development of atherothrombosis, evaluation of the haemostatic factors which are recognized as risk factors may be interesting to consider in these situations. In fact, it has been shown that the fibrinolytic parameters PAI-1 and t-PA antigen are strongly related to the metabolic disorder of insulin resistance, whereas the link with fibrinogen, factor VII, and vWF remains weak. Many cross-sectional studies conducted in different populations have shown that PAI-1 and t-PA antigen (which represents t-PA/PAI-1 complexes) are strongly correlated with insulin, triglyceride, high-density lipoprotein (HDL) cholesterol, body mass index, walst-to-hip ratio and blood pressure, and that the improvement of insulin resistance improves in parallel the metabolic abnormalities and the concentration of the fibrinolytic parameters. Attempts at explaining the elevated PAI-1 and t-PA antigen levels in the insulin resistance syndrome have involved many clinical and in vitro studies, in which the role of insulin, insulin propeptides, very-low-density lipoprotein (VLDL) triglyceride, insulin resistance per se, glucose, and adipose tissue have successively been analysed and the main results of these studies are presented in this review. Due to recent experimental data from animal models of thrombosis, a pathogenic role of decreased fibrinolytic activity or increased PAI-1 levels can be proposed and could play a role in the development of vascular disease in subjects with Type 2 diabetes or insulin resistance.

Prognostic value of plasma fibrinogen concentration in patients with unstable angina and non-Q-wave myocardial infarction (TIMI IIIB Trial)

Inflammation may play an important role in acute coronary syndromes. We studied the prognostic value of fibrinogen, an acute-phase protein directly involved in thrombotic process, measured serially in 1,473 patients with unstable angina and non-Q-wave myocardial infarction participating in the Thrombolysis in Myocardial Infarction IIIB trial. Overall, no association was found between baseline (pretreatment) fibrinogen and in-hospital (< or = 10 days) myocardial infarction (p=0.70) and death (p=0.64); however, patients with spontaneous ischemia (p=0.004) and the combined unsatisfactory outcome of death, myocardial infarction, and spontaneous ischemia (p=0.003) had higher fibrinogen concentrations than those without these events. This association was confined to patients with unstable angina. A baseline fibrinogen concentration > or = 300 mg/dl was associated with a modest trend toward an increased risk of death, myocardial infarction, or spontaneous ischemia (odds ratio 1.61, 95% confidence interval 1.02 to 2.52; p=0.04). Elevation of fibrinogen, a readily measurable acute-phase protein, at the time of hospital admission is associated with coronary ischemic events and a poor clinical outcome in patients with unstable angina.

Long-term influence of fibrinogen on initial and recurrent cardiovascular events in men and women

Examination of the long-term relation of a single fibrinogen determination to initial and recurrent atherosclerotic cardiovascular events over 20 years of follow-up revealed a powerful and comparably independent impact on initial events in both sexes but an influence on recurrent events only in men.

Cardiovascular mortality and morbidity in type-2 diabetes mellitus

A representative number of prospective studies clearly indicate that cardiovascular morbidity and mortality is significantly increased in type-2 diabetic patients in comparison with non-diabetic control subjects. The cardiovascular death rate is 4.4 fold increased in those diabetic patients presenting none of the classical risk factors (hypertension, hypercholesterinemia or smoking) compared with age-matched control subjects (MRFIT). A decreased survival rate after myocardial infarction, congestive heart failure and an increased occurrence of silent ischemia are responsible for the poor prognosis of type-2 diabetic patients. Recent studies indicate that haemostatic abnormalities and endothelial dysfunction are important risk factors for coronary events in diabetic as well as in nondiabetic patients. In newly diagnosed type-2 diabetic patients a similar prevalence of myocardial infarction and angina compared to previously known type-2 diabetes was found. The long prediabetic period and clustering of risk factors may be very relevant for the high prevalence of cardiovascular disease already at diagnosis of type-2 diabetes. More recent studies performed in Scotland and Verona demonstrated a mortality risk approximately only 50% higher than in nondiabetic subjects. The reduction in the mortality risk could reflect an improvement in diabetes prognosis from the 1960s to the 1980s. Recent observations in type-2 diabetic patients from Finland indicate that glycemic control is an important predictor for coronary heart disease morbidity and mortality. However incidence of coronary heart disease is only low in those patients presenting with a HbAlc value below 6.0%. More information will be available after analysis of the United Kingdom prospective diabetes study. (UKPDS).