Relationships of Plasma Viscosity, Coagulation and Fibrinolysis to Coronary Risk Factors and Angina

Blood rheology as a mirror of endocrine and metabolic homeostasis in health and disease1

Rheological properties of plasma and blood cells are markedly influenced by the surrounding milieu: physicochemical factors, metabolism and hormones. Acid/base status, osmolality, lipid status, plasma protein pattern, oxidative stress induced by increased free radicals production, endothelium-derived factors such as nitric oxide (NO), achidonic acid derivatives modulate both red blood cell (RBC) and white cell mechanics. Therefore, regulatory axes involving liver, endothelium, kidney, pancreas, adrenal gland, endocrine heart, adipose tissue, pituitary gland, and surely other tissues play important roles in the regulation of blood fluidity. A comprehensive picture of all this complex network of regulatory loops is still unavailable but current progress of knowledge suggest that some attempts can currently be made.

Reference intervals for whole blood viscosity using the analytical performance-evaluated scanning capillary tube viscometer

OBJECTIVES

This study was performed to establish the reference intervals for whole blood viscosity (WBV) using the analytical performance-evaluated scanning capillary tube viscometer (SCTV).

DESIGN AND METHODS

The analytical performance of the SCTV was evaluated using three different levels of QC materials and sixty human EDTA-blood samples. To establish the reference intervals for WBV, 297 healthy individuals (123 men and 174 women) were selected from 1083 subjects.

RESULTS

Within-day precisions with QC materials and human whole blood and between-day precisions with QC materials were below 5.0%, 6.6% and 8.0% in CVs at all shear rates, respectively. Comparison tests between the SCTV and the Brookfield viscometer showed a significant correlation (R(2)=0.972, p<0.001). The reference intervals for WBV in healthy men were 3.66-5.41cP at 300s(-1) and 23.15-36.45cP at 1s(-1) while those in women were 3.27-4.32cP at 300s(-1) and 18.20-27.36cP at 1s(-1), respectively.

CONCLUSIONS

Using the analytical performance-evaluated SCTV, the reference intervals for WBV were established in healthy adults, which could be beneficial to the clinical utility of WBV in the aspect of appropriate modalities for the improvement of blood viscosity.

Plasma viscosity: is a biomarker for the differential diagnosis of Alzheimer's disease and vascular dementia?

In this study, the importance of plasma viscosity (PV) as a biomarker in differential diagnosis of dementia subtypes especially Alzheimer's disease (AD) and vascular dementia (VaD) was investigated. Our study recruited 45 patients with AD, 35 patients with VaD, and control participants. Individuals with inflammatory disease, infection, heart, liver, renal failure, and with high erythrocyte sedimentation rate and C-reactive protein levels were excluded from the study. The cases underwent comprehensive geriatric assessment. The PV measurements were performed with Brookfield DV-II viscometer. The PV measurements of AD, VaD, and control groups were 1.61 ± 0.08, 1.70 ± 0.06, and 1.48 ± 0.06 mPa S, respectively. The PV levels of the dementia group were significantly higher than the control group (P < .001). When the dementia group was analyzed by itself, patients with VaD had higher PV levels than the patients with AD (P < .001). The PV is a biomarker to be used in diagnosis as well as in differentiating between the 2 most common forms of dementia which are AD and VaD.

Obstructive sleep apnea syndrome: blood viscosity, blood coagulation abnormalities, and early atherosclerosis

Obstructive sleep apnea syndrome (OSAS) is an independent risk factor for atherosclerosis and arterial thrombosis, which are associated with high cardiovascular (CV) morbidity and mortality. In studies performed in clinical populations with elevated CV event risk profiles, the occurrence of moderate to severe OSAS was very often accompanied by a worsened vascular function and increased prevalence of structural abnormalities. Recent investigations of atherosclerosis in OSAS have focused on thrombotic tendency and blood viscosity, providing new insight into mechanisms of the disease. Despite that knowledge about the mechanisms of development of CV disease in patients with OSAS is still incomplete, observations confirm a relationship between sleep-disordered breathing and the rheological properties (flow properties) of blood. While platelet dysfunction and hypercoagulability (PDMPs, PaI-1, and SF) play important roles in the pathogenesis of vascular disease, there are limited studies on the potential role of blood viscosity in the development of vascular disease in OSAS.

Role of hypercoagulability in steroid-induced femoral head necrosis in rabbits

BACKGROUND

The pathogenesis of femoral head necrosis is still uncertain. Both steroid treatment and hypercoagulopathy are considered risk factors. To investigate possible changes in coagulability and histology during steroid-induced osteonecrosis, we used a combination of the Shwartzman reaction and corticoid injections in rabbits to develop an animal model of femoral head necrosis. We studied blood coagulability and histopathological characteristics of the femoral head and liver.

METHODS

A total of 30 rabbits were divided into three groups. In group A, rabbits were given two injections of lipopolysaccharide (40 microg/kg) at an interval of 24 h and were then immediately given one injection of prednisolone acetate (20 mg/kg). In group B, 10 rabbits were given one injection of prednisolone acetate (20 mg/kg). In group C, 10 rabbits were given no treatment and served as controls. At 1, 3, 7, 14, and 21 days after prednisolone injection, coagulability, blood lipid levels, and blood platelet levels were measured; and the femoral head and liver were removed for histopathological examination.

RESULTS

At 24 h after the prednisolone injection in group A, coagulability and blood lipid levels were increased (P < 0.01), and blood platelet levels were decreased (P < 0.01). These abnormal levels were maintained throughout the entire observation period. Histologically, degeneration and necrosis of hepatocytes and osteocytes were found at day 21 after prednisolone injection in group A. In group B, coagulability and blood lipid levels were significantly increased by day 3 after treatment.

CONCLUSIONS

Abnormal hypercoagulability might potentiate the thrombotic status and induce thrombus formation in the presence of steroid-induced necrosis of the femoral head.

Differential effect of high dietary fat intakes on haemorheological parameters in rats

High dietary intake of fats has been thought to be one of the major risk factors for the development of CVD. Less is known about the possible influence of fats from various sources on haemorheological abnormalities, which are considered an important factor in the pathogenesis of these diseases. The goal of the present study was to investigate effects of high-fat diets enriched in unsaturated fatty acids (USFA), SFA or trans-fatty acids (TFA), respectively, on haemorheological parameters in rats. Wistar female rats were divided into four groups and fed diets based on the AIN-93M formulation containing approximately 10 % energy from soyabean oil (control group) or 40 % energy from soyabean oil (USFA), palm oil (SFA) and vegetable shortening (TFA) for 8 weeks. The results showed that rats fed high-fat diets exhibited significant increases in serum TAG levels (P < 0.01), plasma viscosity (P < 0.01), whole blood viscosity (P < 0.01) and internal viscosity (P < 0.01) compared to the controls. The TFA group showed a significant decrease in erythrocyte deformability (P < 0.01) and increase in internal viscosity (P < 0.01) compared with the other groups. In addition, a significant increase in blood levels of free radicals (P < 0.01) was found in the TFA group, suggesting that the attack of oxygen-free radicals could be responsible for the impaired erythrocyte deformability. These impairments could be partly responsible for the development of various circulatory disorders. The present haemorheological study provides additional insights into the potential adverse effects of trans-fat and high-fat diets on haemorheological parameters.

Impaired blood rheology and elevated remnant-like lipoprotein particle cholesterol in hypercholesterolaemic subjects

Blood rheology, fasting serum concentrations of remnant-like lipoprotein particle cholesterol (RLP-C) and concentrations of other lipids were compared in 23 hypercholesterolaemic and 69 normocholesterolaemic subjects, and the relationship between red blood cell (RBC) deformability and RLP-C concentrations were studied in a different set of six hypercholesterolaemic and six normocholesterolaemic subjects. Passage time of whole blood and concentrations of total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C) and RLP-C were significantly higher in hypercholesterolaemic than in normocholesterolaemic subjects. Passage time of whole blood correlated positively with TC, TG, LDL-C and RLP-C and negatively with high-density lipoprotein cholesterol. Furthermore, the passage time of 10% haematocrit-adjusted RBCs in phosphate-buffered saline, which reflects RBC deformability, correlated positively with the passage time of whole blood and RLP-C. Thus, hypercholesterolaemic subjects had impaired blood rheology and elevated RLP-C concentrations, which may be associated with the pathophysiology of atherosclerosis in hypercholesterolaemic subjects. Impaired RBC deformability may contribute to impaired blood rheology associated with elevated RLP-C in hypercholesterolaemic subjects.

Markers of inflammation and hemodynamic measurements in obesity: Copenhagen City Heart Study

BACKGROUND

Low-grade chronic inflammation has been proposed to play a major role in the pathogenesis of hypertension. Low-grade chronic inflammation is also closely associated with obesity, an established causative factor in the development of hypertension. The purpose of this study was to investigate the relationship between two markers of inflammation, C-reactive protein (CRP) and fibrinogen, and blood pressure (BP) and other hemodynamic variables in obese subjects.

METHODS

From a large cardiovascular study based in the general population, we selected subjects with a body mass index (BMI) > or =30 kg/m2, free of major cardiovascular diseases, not taking BP-lowering or lipid-lowering drugs (n = 487; women = 51.1%; median (5th to 95th percentile) age = 62 years (36-80)). The cardiovascular study included measurements of traditional and new risk factors, including ankle brachial BP index, a measure of subclinical atherosclerosis. CRP was determined by a high-sensitive assay.

RESULTS

In partial Spearman rank correlation analysis, adjusted for age and sex, we found no significant relationships between either CRP or fibrinogen and systolic BP, diastolic BP, pulse pressure, or ankle brachial index (rho: -0.057 to 0.068; P > 0.13). However, fibrinogen and CRP were found to be significantly related to heart rate (rho: 0.127-0.169; P < 0.01).

CONCLUSIONS

In this study of generally healthy obese subjects from the general population, we found no significant relationships between markers of inflammation and systolic BP or diastolic BP, showing that obese subjects with higher levels of inflammatory markers do not have higher BP levels than their obese counterparts with lower levels of inflammatory markers.

Relationship between alcohol habits and hemorheology by a micro channel method in a general population

BACKGROUND

Hemorheology plays an important role in the development of cardiovascular disease. The Micro Channel array Flow Analyzer (MC-FAN) (Hitachi Haramachi Electronics Co., Ltd., Bentencho, Japan) is currently considered a useful new device to analyze hemorheology. However, the relationships between various lifestyle habits and hemorheology, especially using MC-FAN, have still not been thoroughly investigated.

HYPOTHESIS

The study was undertaken to determine whether there could be some correlations of lifestyle factors to hemorheology by MC-FAN.

METHODS

A total of 250 asymptomatic Japanese subjects (male:female = 100:150; mean age = 49.7 y) without any medication were enrolled in the present study. Hemorheology was assessed by the whole blood passage time (WBPT) and was corrected by the saline passage time using MC-FAN. Subjects' lifestyle factors, such as smoking habits, alcohol habits, and physical activity, were self-reported.

RESULTS

Partial correlation analysis for WBPT, after controlling for age, gender, hematocrit, white blood cell count, body mass index, blood pressure, blood biochemical measures, and all lifestyle habits, revealed a significant and inverse correlation between alcohol habits of 1-3 go (amount of alcohol intake) and WBPT (r = - 0.191, p = 0.003), in addition to a significant positive correlation between serum low-density lipoprotein (LDL) cholesterol and WBPT.

CONCLUSIONS

These data suggest that alcohol habits may beneficially affect hemorheology by MC-FAN, expanding the protective effect of light-to-moderate alcohol consumption against cardiovascular disease.

Homocysteine and fibrinogen changes with L-thyroxine in subclinical hypothyroid patients

The aim of the present study was to evaluate plasma total homocysteine (Hcys) and serum fibrinogen concentrations in subclinical hypothyroid (SH) and overt hypothyroid patients before and after L-thyroxine (LT4) replacement and to compare them in euthyroid subjects. Fifteen SH and 20 hypothyroid premenopausal women were recruited in the study. We measured fasting plasma levels of Hcys and serum levels of free thyroxine (fT4), free triiodothyronine (fT3), thyrotropin (TSH), folate, vitamin B12, fibrinogen, renal functions, and lipid profiles in patients with SH and overt hypothyroid patients before and after LT4 treatment. Eleven healthy women were included in the study as a control group. Pretreatment Hcys levels were similar in SH and control subjects, whereas mean fibrinogen level of SH patients was higher than that of control subjects (p<0.05). Baseline Hcys (p<0.01) and fibrinogen (p<0.001) levels of the overt hypothyroid patients were significantly higher than those of the healthy subjects, and the pretreatment Hcys levels decreased with LT4 treatment (p<0.001). In conclusion, our data support that SH is not associated with hyperhomocysteinemia and Hcys does not appear to contribute to the increased risk for atherosclerotic disease in patients with SH.

Relative Value of Inflammatory, Hemostatic, and Rheological Factors for Incident Myocardial Infarction and Stroke

Background— The aim of our present study was to compare the association of a wide range of 17 biomarkers of inflammation, hemostasis, and blood rheology with incident heart disease and stroke after accounting for an indicator of subclinical atherosclerotic disease and traditional risk factors and also to determine their incremental predictive ability.

Methods and Results— We used data from the Edinburgh Artery Study, a population cohort study started in 1987 that comprised 1592 men and women aged 55 to 74 years. Subjects were followed for a mean of 17 years, and 416 of them suffered at least 1 cardiovascular event. In analyses adjusted for cardiovascular risk factors and history of cardiovascular disease (CVD): C-reactive protein, interleukin-6, fibrinogen, fibrin D-dimer, tissue plasminogen activator (t-PA), leukocyte elastase, and lipoprotein(a) (all P <0.01), as well as von Willebrand factor and plasma viscosity (both P <0.05), had significant hazard ratios for incident CVD. Further adjustment for a measure of subclinical atherosclerosis (ankle brachial index) had little impact on these associations. The hazard ratios (95% CI) for incident CVD between top and bottom tertiles in the latter analysis were 1.78 (1.30 to 2.45) for C-reactive protein, 1.85 (1.33 to 2.58) for interleukin-6, and 1.76 (1.35 to 2.31) for fibrinogen. Single biomarkers provided little additional discrimination of incident CVD to that obtained from cardiovascular risk factors and the ankle brachial index. An incremental score of multiple markers [interleukin-6, t-PA, intercellular adhesion molecule 1, and lipoprotein(a)] provided some added discrimination.

Conclusions— Several “novel” risk factors predicted CVD after adjustments for conventional risk factors and also for a measure of asymptomatic disease. However, their incremental predictive ability was modest and their clinical utility remains uncertain.

Positive Association Between Plasma Fibrinogen Level and Incident Hypertension Among Men

Elevated plasma fibrinogen is implicated in cardiovascular disease. However, it is not clear whether fibrinogen levels predict the development of hypertension. We examined the relationship between plasma fibrinogen level and hypertension in a population-based cohort study of 3654 participants (mean age: 61.5 years; range: 49 to 84 years) at the baseline examination (1992-1994) in the Blue Mountains region, west of Sydney, Australia, who were examined 5 years (1997-1999) later. Main outcomes of interest were prevalent hypertension (systolic blood pressure >or=140 mm Hg, diastolic blood pressure >or=90 mm Hg, or a combination of self-reported hypertension diagnosis and use of antihypertensive medications) at baseline (n=2212/3180) and 5-year incidence of hypertension among baseline normotensive individuals (n=361/637). Elevated plasma fibrinogen level was positively associated with prevalent hypertension both among men and women and positively associated with 5-year incident hypertension among men, independent of several cardiovascular risk factors. Multivariable odds ratio (95% CI) of 5-year incident hypertension comparing tertile 3 of plasma fibrinogen (>or=3.9 g/L) with tertile 1 (<or=3.2 g/L) was 1.95 (1.03 to 3.68; P trend=0.040). This prospective association, however, was not observed in women (odds ratio; 95% CI) comparing tertile 3 versus tertile 1 of plasma fibrinogen (1.00; 0.54 to 1.86; P trend=0.986). Subgroup analyses stratified by smoking, body mass index, diabetes, and blood pressure categories supported this male gender-specific pattern of association. These data provide prospective epidemiological evidence of an essential link between plasma fibrinogen level and incident hypertension among men but not among women, a finding consistent with that observed in the Atherosclerosis Risk in Communities Study.

Hemostatic factors, inflammatory markers, and progressive peripheral atherosclerosis: the Edinburgh Artery Study

The interplay between inflammatory and hemostatic mechanisms may play a crucial role in the development and progression of atherosclerosis. The authors evaluated the separate and joint associations of hemostatic and inflammatory variables on peripheral atherosclerotic progression in the Edinburgh Artery Study, a population cohort study of 1,592 men and women aged 55-74 years that started in 1987. Levels of fibrinogen, fibrin D-dimer, von Willebrand factor, tissue plasminogen activator antigen, factor VII, prothrombin fragment 1 + 2, urinary fibrinopeptide A, C-reactive protein, and interleukin-6 were measured at baseline. Arm and ankle blood pressures were measured, and atherosclerotic progression was assessed by computing ankle brachial index (ABI) at baseline (1,582 participants) and after 12 years of follow-up (813 participants). Fibrinogen (p = 0.05) and D-dimer (p < or = 0.05) were significantly associated with ABI change independently of baseline ABI and cardiovascular disease risk factors. However, these associations were no longer significant when analyses were adjusted for either C-reactive protein or interleukin-6. Moreover, subjects with higher levels of both D-dimer and interleukin-6 at baseline had the greatest ABI decline. In conclusion, fibrinogen and D-dimer, but not other hemostatic factors, were associated with progressive peripheral atherosclerosis. Since D-dimer and fibrinogen are acute phase reactants, these data support the hypothesis that inflammation is more related to atherosclerosis than is hypercoagulation.

Hemorheological abnormalities in lipoprotein lipase deficient mice with severe hypertriglyceridemia

Severe hypertriglyceridemia (HTG) is a metabolic disturbance often seen in clinical practice. It is known to induce life-threatening acute pancreatitis, but its role in atherogenesis remains elusive. Hemorheological abnormality was thought to play an important role in pathogenesis of both pancreatitis and atherosclerosis. However, hemorheology in severe HTG was not well investigated. Recently, we established a severe HTG mouse model deficient in lipoprotein lipase (LPL) in which severe HTG was observed to cause a significant increase in plasma viscosity. Disturbances of erythrocytes were also documented, including decreased deformability, electrophoresis rate, and membrane fluidity, and increased osmotic fragility. Scanning electron microscopy demonstrated that most erythrocytes of LPL deficient mice deformed with protrusions, irregular appearances or indistinct concaves. Analysis of erythrocyte membrane lipids showed decreased cholesterol (Ch) and phospholipid (PL) contents but unaltered Ch/PL ratio. The changes of membrane lipids may be partially responsible for the hemorheological and morphologic abnormalities of erythrocytes. This study indicated that severe HTG could lead to significant impairment of hemorheology and this model may be useful in delineating the role of severe HTG in the pathogenesis of hyperlipidemic pancreatitis and atherosclerosis.

Interleukin-6, Fibrin D-Dimer, and Coagulation Factors VII and XIIa in Prediction of Coronary Heart Disease

OBJECTIVE

Activated inflammation and activated blood coagulation are believed to increase the risk of coronary thrombosis and are related. We therefore compared plasma IL-6 (a key cytokine in the inflammatory process), fibrin D-dimer (a marker of fibrin turnover), and coagulation factors VII and XIIa (initiators of extrinsic and intrinsic blood coagulation, respectively) as predictors of coronary risk in the West of Scotland Coronary Prevention Study of pravastatin in men with hypercholesterolemia.

METHODS AND RESULTS

485 men who had had a coronary event (nonfatal myocardial infarction, death from coronary heart disease, or revascularization) were matched for age and smoking status with 934 controls. Baseline IL-6 and D-dimer were strong univariate predictors of coronary risk (relative risk in the highest quintile approximately twice that in the lowest quintile) and were associated with each other and with C-reactive protein. On multivariate analyses, D-dimer retained a significant association with coronary risk (relative risk, 1.86; 95% CI, 1.24 to 2.80), whereas IL-6 (1.47; 0.95 to 2.28) and C-reactive protein (1.33; 0.85 to 2.08) did not. Neither factor VII nor factor XIIa antigens were predictors of coronary events.

CONCLUSIONS

Fibrin D-dimer may be a stronger predictor of coronary risk than inflammatory markers, perhaps through its ability to stimulate monocyte release of IL-6.

Hemostatic system as a risk factor for cardiovascular disease in women with subclinical hypothyroidism

Hypothyroidism has been associated with atherosclerosis. The mechanisms of atherosclerosis in patients with thyroid failure remain controversial. Hypofibrinolysis might be a risk factor for thromboembolic disease in subclinical hypothyroidism (SH). We measured fibrinolytic activity in patients with SH before and after levothyroxine (LT(4)) treatment and compared it to those of controls. We prospectively included 35 patients with SH and 30 healthy controls. We treated patients with LT(4) until almost 6 months after the euthyroid state has been achieved. We measured fibrinogen, D-dimer, antithrombin III (ATIII), plasminogen activator inhibitor-1 (PAI-1), tissue plasminogen activator (tPA) activity, and factor VII. Clinical and anthropometric variables were recorded for both groups. We found increased levels of fibrinogen, PAI-1, and factor VII and decreased levels of ATIII activity in patients compared to control (p < 0.001 and p < 0.05). Decrease of tPA was not significant (p > 0.05). At the end of the LT(4) treatment, significant decreases were determined in PAI-1 and factor VII (p < 0.05). In conclusion, our data suggest an important role of hypofibrinolytic and hypercoagulable state on the development of atherosclerosis in patients with SH and beneficial effects of LT(4 )treatment for decreasing the risk of atherosclerosis.

Hematocrit is associated with carotid atherosclerosis in men but not in women

BACKGROUND

It is known that blood and plasma viscosities are associated with clinical manifestations of atherosclerosis, though evidence is not conclusive particularly in women.

OBJECTIVE

To verify whether hematocrit and blood and plasma viscosities are independently associated with carotid atherosclerosis and whether their measurement can improve the definition of the global coronary heart disease (CHD) risk.

METHOD

Eight hundred and ninety-two participants in a cardiovascular disease prevention campaign were examined with regard to conventional CHD risk factors (age, blood pressure, lipids, glucose, body mass index, waist/hip ratio, cigarette smoking and diabetes), hematocrit and blood and plasma viscosities. According to the degree of carotid atherosclerosis, investigated by echo-Doppler, participants were divided in three groups: those without atherosclerosis, those with a low degree of atherosclerosis and those with a high degree of atherosclerosis.

RESULTS

In men, age, blood pressure, intima-media thickness (IMT), hematocrit (47.4+/-3.7%, 47.8+/-3.7%, 48.4+/-3.7%, P<0.05) and blood viscosity (4.69+/-0.51 cP, 4.77+/-0.55 cP, 4.82+/-0.51 cP, P=0.05) increased with increasing degree of carotid atherosclerosis. In women, age, blood pressure, total cholesterol and low-density lipoprotein-cholesterol, IMT and plasma viscosity (1.42+/-0.12 cP, 1.44+/-0.11 cP, 1.46+/-0.13 cP, P<0.05) increased with increasing carotid score. Analysis of covariance (ANCOVA) showed that after adjusting for hematocrit, blood viscosity was no longer different in the three groups. In discriminant analysis, hematocrit, among the hemorheological variables investigated, was independently associated with carotid score in men (F=3.66, P<0.05). Neither hematocrit nor blood and plasma viscosities were significantly associated with carotid score in women.

CONCLUSION

These findings suggest that in men, both hematocrit and blood viscosity are related to carotid atherosclerosis but hematocrit would appear to have an independent effect over and above that mediated by viscosity.

Effects of folic acid supplementation on inflammatory and thrombogenic markers in chronic smokers. A randomised controlled trial

INTRODUCTION

Cigarette smoking may induce pro-inflammatory and pro-thrombotic changes. It is not known whether these abnormalities are caused at least partly by increased homocysteine levels. We investigated whether lowering homocysteine by folic acid supplementation might reduce the plasma concentration of inflammatory and thrombogenic markers in chronic smokers.

MATERIAL AND METHODS

Twenty-four healthy cigarette smokers (age 37.8+/-2.5 years, mean+/-SEM) were randomly assigned to 4 weeks of folic acid 5 mg/day or placebo. The following parameters were measured before and after treatment: (1) markers of inflammation (C-reactive protein, CRP, and white cell count, WCC); (2) blood coagulation screen (Activated Partial Thromboplastin time Ratio, APTR, and International Normalized Ratio, INR); (3) pro-thrombotic markers (fibrinogen, factor VIII coagulant activity, VIII:C, von Willebrand factor, vWF, and D-dimer).

RESULTS

Folic acid induced a significant reduction in homocysteine (10.8+/-0.6 vs. 8.2+/-0.5 micromol/l, p<0.001), plasma fibrinogen (3.15+/-0.14 vs. 2.87+/-0.14 g/l, p<0.05), and D-dimer (102+/-44 vs. 80+/-26 microg/l, p<0.05) concentrations. By contrast, no significant changes were observed in CRP (2.2+/-0.7 vs. 1.7+/-0.7 mg/l), WCC (7.2+/-0.5 vs. 6.8+/-0.5 10(9) cells/l), APTR (0.91+/-0.02 vs. 0.93+/-0.02), INR (0.92+/-0.01 vs. 0.91+/-0.01), vWF (103+/-8 vs. 102+/-9 U/dl), and VIII:C (120+/-8 vs. 107+/-8 U/dl) levels. Changes in folic acid plasma concentrations were significantly and negatively correlated with changes in fibrinogen (r=-0.48, p=0.01) but not with changes in D-dimer (r=-0.15, p=0.5) levels. Changes in plasma homocysteine concentrations did not correlate with changes in either fibrinogen or D-dimer. No significant changes in homocysteine, inflammatory and thrombogenic markers were observed in the placebo group.

CONCLUSIONS

Short-term folic acid supplementation had no significant effects on inflammatory markers but induced a significant reduction in plasma fibrinogen and D-dimer concentrations in healthy chronic smokers. Thus, folic acid might have an anti-thrombotic effect in this high-risk group independent of the homocysteine lowering effect.

Intraindividual comparison of two extracorporeal LDL apheresis methods: lipidfiltration and HELP

Low density lipoprotein (LDL) apheresis is an effective treatment option for patients with severe hypercholesterolemia not adequately responding to diet and drug therapy. Membrane differential filtration (MDF), synonymous with double filtration plasmapheresis (DFPP), here named Lipidfiltration, and heparin-induced extracorporeal LDL-precipitation (HELP) are two of the five methods available for extracorporeal LDL apheresis. In this prospective investigation 6 patients with severe LDL-hypercholesterolemia and CAD were treated in a cross-over design with Lipidfiltration at two stages of technical development and HELP to compare the efficacy of these two LDL apheresis methods with respect to lowering and modifying plasma lipids and rheologically relevant plasma proteins, especially fibrinogen. In total, 44 LDL apheresis sessions were investigated. In weekly intervals, patients were treated with consecutive LDL apheresis sessions with either Lipidfiltration and HELP, treating identical plasma volumes. In one part of the investigation Lipidfiltration was performed with the novel Lipidfilter EC-50, combined with a newly developed blood and plasma therapy machine allowing optimized plasma heating. The results showed that the reduction rates of LDL-cholesterol, lipoprotein(a) and triglycerides were essentially identical for both methods. Also pretreatment levels of total cholesterol, triglycerides, LDL-cholesterol and HDL-cholesterol were not significantly different in both treatment groups. Both methods lead to a significant reduction of serum lipoproteins, especially for LDL-cholesterol, which was decreased by 61.4% with Lipidfiltration (treated plasma volume: 2998 ml) and 61.3% with HELP (treated plasma volume: 3013 ml). With respect to Lipidfiltration LDL-cholesterol reduction was more efficient with the novel Lipidfilter EC-50. Mean pretreatment HDL cholesterol concentrations remained unchanged. Comparing Cascadeflo AC-1770 with the novel Lipidfilter EC-50 reduction rates of HDL-cholesterol (17.4% versus 6.4%) and total protein (17.9% versus 7.8%) were significantly reduced. Lipidfiltration and HELP both resulted in a reduction of plasma viscosity and hemorheologically relevant plasma proteins, like fibrinogen.

The role of whole blood viscosity in premature coronary artery disease in women

BACKGROUND

Impaired hemorheology has been demonstrated in atherosclerotic disease and has shown a relationship with classical risk factors. Blood viscosity (eta), being the ratio of shear stress over shear rate, is an important parameter of hemorheology. In women with premature coronary artery disease (CAD), the underlying risk factors are a matter of debate and the role of whole blood viscosity in its pathogenesis has not been documented.

AIM

To investigate the association of whole blood viscosity with premature CAD in women, with complaints suggestive of angina pectoris.

METHODS

Eighty-eight women (mean age 53 years) were divided into two groups, those with a high likelihood of CAD (LIKELI+) and those with a low likelihood of CAD (LIKELI-), based on medical history and technical investigations. Assessment of risk factors comprised smoking, diabetes mellitus, arterial hypertension, left ventricular hypertrophy (LVH), systolic and diastolic blood pressures, total low-density lipoprotein (LDL)- and high-density lipoprotein (HDL)-cholesterol, triglycerides, body mass index, menopause, hormone replacement therapy, uric acid and creatinine, and predicted 10-year cardiovascular risk according to the Framingham study was calculated. Whole blood viscosity was determined at 37 degrees C using a rotational cone-and-plate viscosimeter.

RESULTS

Baseline characteristics did not differ significantly between the groups except for antiplatelet therapy (P=0.001), prevalence of diabetes mellitus (P=0.002), predicted 10-year cardiovascular risk (P=0.007), essential hypertension (P=0.02), LVH (P=0.03) and smoking habits (P=0.04). LIKELI+ women had a significantly higher whole blood viscosity at all shear rates compared with LIKELI- women (P<0.05). All blood viscosities measured from 25 to 125 s(-1) were highly significantly (P<0.0001) correlated with eta(250s(-1)). Univariate correlates with eta(250s(-1)) comprised triglycerides (P=0.006) and haematocrit (P=0.026). Binary logistic multivariate regression analysis for high likelihood of CAD revealed that only presence of arterial hypertension (P<0.0001) was predictive. Multiple regression analysis demonstrated that haematocrit (P=0.001) and likelihood of CAD (P=0.01) were the only significant determinants of eta(250s(-1)).

CONCLUSION

In this study, blood viscosity did not appear as an independent risk factor for the prediction of premature CAD in women. Viscosity may act as a marker of CAD or of classical risk factors.

Marked removal of bezafibrate-induced high-density lipoprotein-cholesterol by low-density lipoprotein apheresis

BACKGROUND

A case of marked reduction of the bezafibrate-induced increase of high-density lipoprotein (HDL)-cholesterol by low-density lipoprotein apheresis (LDL-apheresis) has not been previously reported.

METHODS

A 68-year-old Japanese man with arteriosclerosis obliterans (ASO), diabetes mellitus, and hyperlipidemia underwent LDL-apheresis, followed by the concomitant bezafibrate administration. Plasma lipids of pre- and post-LDL-apheresis were measured and apolipoprotein E (apoE) localization of the pre- and post-LDL-apheresis was detected by agarose gel electrophoresis.

RESULTS

Plasma concentrations of the total cholesterol, LDL-cholesterol, triglyceride, and HDL-cholesterol of pre-LDL-apheresis were 4.78 +/- 0.36, 2.74 +/- 0.24, 2.44 +/- 0.52, and 0.92 +/- 0.10 mmol/l, respectively; those of the post-LDL-apheresis were 1.94 +/- 0.31, 0.72 +/- 0.13, 0.81 +/- 0.38, and 0.86 +/- 0.11 mmol/l, respectively. LDL-apheresis reduced HDL-cholesterol by 6.4% (p=0.346). During the bezafibrate administration, plasma concentrations of the above of pre-LDL-apheresis were 5.24 +/- 0.34, 3.28 +/- 0.22, 1.26 +/- 0.25, and 1.39 +/- 0.21 mmol/l, respectively; those of the post-LDL-apheresis were 2.25 +/- 0.44, 0.80 +/- 0.12, 0.58 +/- 0.19, and 1.18 +/- 0.16 mmol/l, respectively. LDL-apheresis reduced HDL-cholesterol by 15.2% (p<0.01). Plasma apolipoprotein E detected between the prebeta- and alpha-mobility was markedly lower after the LDL-apheresis in the agarose gel electrophoresis.

CONCLUSIONS

The removal of the bezafibrate induced an increase of the HDL-cholesterol by LDL-apheresis.

Hypertriglyceridemia is associated with an elevated blood viscosity Rosenson: triglycerides and blood viscosity

Elevated blood viscosity is a predictor of cardiovascular disease. The major determinants of blood viscosity are hematocrit and plasma viscosity. Plasma triglycerides elevate plasma viscosity; however, the contribution of plasma triglycerides to blood viscosity after adjustment for other major covariates has not been reported. This cross-sectional study of 257 adult subjects evaluated the associations between fasting plasma lipids, fibrinogen, total serum protein, hematocrit and blood viscosity. Blood viscosity was measured at 37 degrees C with a coaxial cylinder microviscometer at shear rates of 100 and 1 s(-1). Blood viscosity values are reported both as uncorrected measurements and measurements corrected to a hematocrit of 45% by a regression equation. Uncorrected blood viscosity at a shear rate of 100 s(-1) was significantly associated with triglycerides, fibrinogen, high density lipoprotein (HDL) cholesterol, total serum protein, and hematocrit using stepwise multivariate regression analysis. When corrected blood viscosity at 100 s(-1) was the dependent variable, there were statistically significant associations with triglycerides, HDL cholesterol, and total serum protein. Corrected blood viscosity at 1 s(-1) was significantly associated with triglycerides, fibrinogen, total serum protein, and an indicator variable for diabetes mellitus. This study supports an additional mechanism whereby triglycerides may contribute to cardiovascular risk.

Primary cutaneous microangiopathy in heart recipients

In this study we investigated whether a disturbance in microcirculation is detectable in heart recipients with cardiac allograft vasculopathy (CAV) and severe hypercholesterolemia (n = 11) and in 7 heart recipients without CAV in comparison to patients with severe coronary artery disease (n = 49) and age-matched apparently healthy subjects (n = 100). For this purpose, the flow velocity of erythrocytes through cutaneous capillaries at the nail fold of the finger was measured under resting conditions. In addition, reactive hyperemia in the same capillaries after a 3-min ischemia was determined. Patients with CAV and severe lipid disorder showed a pathological reduction in mean capillary erythrocyte velocity under resting conditions with v(RBC) = 0.10 +/- 0.07 mm/s. The latter was significantly and relevantly lower than in patients with coronary three-vessel disease (v(RBC) = 0.46 +/- 0.35 mm/s). It was notable that under resting conditions temporary cessation of flow occurred in 8 of the 11 patients which did not occur in healthy subjects and rarely in patients with three-vessel disease (1 of 49 patients). In comparison to age-matched healthy subjects (v(max) = 1.46 +/- 0.52 mm/s), the patients with three-vessel disease showed a significant reduction in postischemic maximum erythrocyte velocity (v(max) = 0.85 +/- 0.55 mm/s), with a considerable shortening of the duration of reactive hyperemia. Patients with CAV demonstrated a total loss of postischemic reactive hyperemia (only 1 of the 11 patients presented a weak reactive hyperemia). Since no macroangiopathy was detectable in the upstream arm arteries, primary cutaneous microangiopathy can be assumed in patients with cardiac allograft vasculopathy and severe hypercholesterolemia.

Plasma fibrinogen in relation to the severity of arteriosclerosis in patients with stable angina pectoris after myocardial infarction

BACKGROUND

Authors both of retrospective and of prospective studies have demonstrated that there is a relationship between concentration of fibrinogen in plasma and the angiographically determined severity of coronary heart disease (CHD).

OBJECTIVE

To determine the relevance of the plasma fibrinogen concentration for the severity of CHD, particularly in cases with additional arteriosclerotic changes in the extracranial arteries supplying the brain [cerebrovascular disease (CVD)], in the pelvic/leg arteries [peripheral occlusive arterial disease (POAD)], or in both.

PATIENTS AND METHODS

In a retrospective cross-sectional survey the cardiological and angiographical status of a total of 1112 male and 299 female patients with stable angina pectoris after sustained myocardial infarction and an age-matched control group of 326 male and 138 female subjects with no clinical symptoms of CHD was determined, together with measurements of plasma fibrinogen, dynamic plasma viscosity and D-dimers.

RESULTS

More than two-thirds of the patients with arteriosclerosis had plasma fibrinogen concentrations in the uppermost tertile of the control range (men > 2.75; women > 2.83 g/l). Plasma fibrinogen concentration was correlated to the severity of CHD (for men r = 0.173, P < 0.001; for women r= 0.144, P < 0.013). Patients with generalized arteriosclerosis had higher plasma fibrinogen concentrations than did those suffering from CHD only (for men, control 2.65 +/- 0.51, CHD 3.07 +/- 0.73, CHD plus POAD 3.17 +/- 0.77 and CHD plus POAD plus CVD 3.45 +/- 0.78 g/l; for women, control 2.69 +/- 0.44, CHD 3.25 +/- 0.67, CHD plus POAD 3.19 +/- 0.77, CHD plus POAD plus CVD 3.60 +/- 0.84 g/l). Multivariate analysis showed that C-reactive protein, D-dimers and dynamic plasma viscosity accounted for 48.2% (for men) and 49.4% (for women) of the variance in plasma fibrinogen concentration.

CONCLUSIONS

Our findings demonstrate that there is not only a correlation between plasma fibrinogen concentration and the severity of CHD, but also a correlation to the incidence of additional POAD or CVD.

Smoking, other risk factors and fibrinogen levels. evidence of effect modification

PURPOSE

Recent investigations have indicated that smoking may act as an important modifier of the risk associated with dyslipidemia. We hypothesized as a potential mechanism that smoking modifies the association between traditional risk factors of early atherosclerosis, such as dyslipidemia, hypertension, or diabetes, with fibrinogen, a risk factor more closely related to plaque progression and thrombosis.

METHODS

The sample for this cross-sectional study, was collected from the MONICA Augsburg population survey of 1989/90 and included 1840 men and 1784 women, aged 25 to 64 years. Traditional risk factors hypertension, diabetes mellitus, and dyslipidemia were assessed by personal interviews, and medical examinations. Plasma fibrinogen concentration was determined by nephelometry. Effect modification was assessed by stratified analyses and tests for statistical interaction.

RESULTS

Fibrinogen levels were higher in women than in men and, after adjustment for potential confounders, higher in smokers than in nonsmokers (each p < 0.001). The effect of smoking was greater in men (p < 0.001). The elevation of mean adjusted fibrinogen levels associated with hypertension or with diabetes in men was significantly higher in smokers as compared to nonsmokers (test for interaction, p < 0.001). By contrast, smoking in women showed significantly stronger impacts only with regard to the association of dyslipidemia and fibrinogen (p < 0.001). Comparing groups of subjects with increasing numbers of concomitant risk factors, stratified according to their smoking status, effect modification by smoking was particularly evident in male participants with two or more risk factors. Numbers of women with more than one risk factor and smoking were too low for analysis.

CONCLUSIONS

We demonstrate that smoking contributes more than additively to the strong influences of single and combined traditional risk factors on fibrinogen levels. These data confirm that smoking is a dominant determinant of fibrinogen levels in the general population.

Changes in hemostasis during treatment of hypertriglyceridemia with a diet rich in monounsaturated and n-3 polyunsaturated fatty acids in comparison with a low-fat diet

High levels of fibrinogen, factor (F) VIIc, plasminogen activator inhibitor-1 (PAI-1), and plasma viscosity are associated with an increased coronary risk. As positive correlations of these parameters with triglycerides have been shown, the increased coronary risk associated with high levels of triglycerides may be assumed to be due to alterations within the hemostatic system. To reduce the coronary risk to which hypertriglyceridemic patients are exposed, dietary treatment is recommended; the optimal composition of such a diet is, however, a matter of debate. With regard to the effects on hemostasis, we compared in a sequential approach two diets for treatment of 25 nonobese male patients (age, mean+/-S.D., 40.4+/-8.7 years) with fasting triglycerides >2.3 mmol/l. The first diet (high fat) was rich in monounsaturated fatty acids (MUFA) and marine n-3 polyunsaturated fatty acids (PUFA), whereas the second diet (low-fat) was rich in complex carbohydrates and dietary fiber. The high-fat diet induced a significant lowering of FIIc, FIXc, FXc, FVIIc, FVIIa, FXIIa, PAI-1, plasma viscosity, and platelet activity, but led to an increase in fibrinogen, whereas the low-fat diet lowered FXIIc values and induced a nonsignificant decrease in fibrinogen. Probands on this diet had a slightly higher FVIIa and platelet activity than those on the high-fat diet. However, as all changes appeared to be within the normal range of each hemostatic parameter, it remains to be clarified whether the likely beneficial effects of the high-fat diet on most hemostatic factors are outweighed by the small increase in fibrinogen levels.

Effect of the angiotensin-converting enzyme inhibitor perindopril on haemostasis in essential hypertension

Endothelial damage, platelet hyperactivity and other changes of blood coagulation may play a role in the vascular complications of essential hypertension. Undesirable changes of haemostasis induced by some anti-hypertensive drugs can encourage the acceleration of atherogenesis. Therefore, the effect of angiotensin-converting enzyme (ACE)-inhibitors on haemostasis is of interest. The therapeutic dose of perindopril was previously shown to reduce platelet aggregation. In the present study, selected parameters of haemostasis were investigated in 23 patients with first and second stage of non-treated essential hypertension. The measurements were carried out before therapy, after 1 week of placebo administration, and after 1 week and after 1 month of ACE-inhibitor perindopril therapy in a once-daily dose of 4 mg. Plasma prothrombin time, activated partial thromboplastin time, fibrinogen level, plasminogen and antithrombin III activities, protein C and free protein S antigens, total fibrinolytic activity as well as fibrin monomers and D-dimers were assayed. There were no significant changes in any haemostasis variables investigated following placebo administration or perindopril therapy. On the basis of this study, no unfavourable effects on haemostasis induced by this therapy were found. The platelet-inhibitory effect of perindopril, without any harmful effects on coagulation or fibrinolytic activity and coagulation inhibitors, is desirable in the new approach to hypertension treatment. These properties of perindopril may be important in terms of the beneficial role of anti-hypertensive drugs in cardiovascular morbidity.

Effect of gemfibrozil on peripheral atherosclerosis and platelet activation in a pig model of hyperlipidemia

BACKGROUND

Gemfibrozil has been shown to have beneficial effects in the primary and secondary prevention of atherosclerosis. However, a platelet pro-activating effect induced by the drug has been reported.

MATERIAL AND METHODS

We analysed the effect of hyperlipidemia and its treatment with gemfibrozil on platelet-fibrinogen binding and the development of early fibrinogen-rich vascular lesions in a porcine model of atherosclerosis. Polyclonal antibodies were raised against purified pig fibrinogen and intact platelets. Two groups of animals were fed a cholesterol/saturated fat-enriched diet for 50 days; one group was treated with gemfibrozil and the other with placebo.

RESULTS

The hyperlipidemic diet induced a significant increase in total cholesterol; this was prevented by gemfibrozil (P<0.05). The increase in platelet-fibrinogen binding induced by hypercholesterolemia was mildly reduced in the gemfibrozil treated animals. Histological analysis of aortic vascular wall (abdominal aorta at the iliac bifurcation) from hyperlipidemic animals showed early lesions with fibrinogen infiltration; the lesions were reduced in the fibrate-treated animals.

CONCLUSIONS

Gemfibrozil delayed the development of peripheral atherosclerotic plaque, normalised the impaired lipid profile induced by the hyperlipidemic diet and did not show a functionally detectable platelet pro-activating effect able to increase platelet-fibrinogen binding.

Hyperlipidemia promotes thrombosis after injury to atherosclerotic vessels in apolipoprotein E-deficient mice

The increased risk of hyperlipidemia on the development of complications of atherosclerosis is well established. Cholesterol-lowering therapies lead to a decrease in the incidence of vascular thrombotic events that is out of proportion to the reduction in plaque size. This suggests that the occurrence of acute thrombosis overlying a disrupted plaque is influenced by changes in lipid levels. The influence of acute hyperlipidemia on the development of thrombosis overlying an atherosclerotic plaque in vivo has not been extensively studied. We used a murine model of vascular injury induced by a photochemical reaction to elicit thrombus formation overlying an atherosclerotic plaque. Fifteen apolipoprotein E-deficient mice were maintained on normal chow until the age of 30 weeks. Five days before the induction of thrombosis, 6 mice were started on a high fat diet, and 9 mice were continued on normal chow. Mice then underwent photochemical injury to the common carotid artery immediately proximal to the carotid bifurcation, where an atherosclerotic plaque is consistently present. Mice maintained on normal chow developed occlusive thrombi, determined by cessation of blood flow, 44+/-5 minutes (mean+/-SEM) after photochemical injury, whereas mice fed a high fat chow developed occlusive thrombosis at 27+/-3 minutes (P<0.02). Histological analysis confirmed the presence of acute thrombus formation overlying an atherosclerotic plaque. These studies demonstrate a useful model for assessing the determinants of thrombosis in the setting of atherosclerosis and show that acute elevations in plasma cholesterol facilitate thrombus formation at sites of atherosclerosis after vascular injury.

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.

Methylene tetrahydrofolate reductase (MTHFR) and nitric oxide synthase (ecNOS) genes and risks of peripheral arterial disease and coronary heart disease: Edinburgh Artery Study

Hyperhomocysteinaemia and reduced nitric oxide synthesis may each result in endothelial dysfunction predisposing to atherogenesis. Genetic variants of methylene tetrahydrofolate reductase (MTHFR) and endothelial nitric oxide synthase (ecNOS) influence homocysteine metabolism and nitric oxide synthesis, respectively and might thus be determinants of the risk of atherosclerotic disease. The aim of our study was to identify, in a general population sample, the risks of peripheral arterial disease and of coronary heart disease related to MTHFR (175;198) and ecNOS (4;5) polymorphisms. In the Edinburgh Artery Study, which is a population based cohort study, 940 men and women aged 60-79 years, who had previously been selected at random from the general population, had DNA extracted from a venous blood sample. Based on a clinical examination at baseline and follow up investigations, three groups of subjects were identified: those with peripheral arterial disease (n=80), those with coronary heart disease (n=137), and healthy controls who had no evidence of cardiovascular disease (n=300). The distributions of the ecNOS and MTHFR genotypes did not differ significantly between the groups with and without cardiovascular disease. However, the ecNOS-4 allele (frequency 0.13) was related to the occurrence of coronary heart disease in non smokers, OR=2.47 (95% CI [1.42, 4.34], P=0.02). No association was found with peripheral arterial disease. The MTHFR-175 allele (frequency 0.31) was not related to coronary heart disease, but was associated with a reduced risk of peripheral arterial disease, OR=0.54 (95% CI [0.32, 0.90], P=0.02). Neither the ecNOS-4 allele or MTHFR-175 allele was related to the ankle brachial pressure index in the whole study population. In conclusion, the ecNOS-4 allele was associated with a slightly increased risk of coronary heart disease in non-smokers, but otherwise the MTHFR and ecNOS genotypes appeared to have little influence on the risks of peripheral arterial disease and coronary heart disease in this older population.

Serum C-reactive protein and fibrinogen concentrations and self-reported angina pectoris and myocardial infarction: findings from National Health and Nutrition Examination Survey III

C-reactive protein may predict the risk of cardiovascular disease, but its association with angina pectoris in the general population has not been clearly established, however. We used data from National Health and Nutrition Examination Survey III conducted from 1988-1994 to examine the associations between serum C-reactive protein and plasma fibrinogen concentrations and self-reported angina pectoris and myocardial infarction among 7,948 U.S. men and women aged 40 years and older. C-reactive protein and fibrinogen concentrations were moderately correlated (r = 0.43). After adjustment for age, sex, race or ethnicity, education, smoking status, systolic blood pressure, serum cholesterol, high-density lipoprotein cholesterol, history of diabetes mellitus, body mass index, and physical activity, fibrinogen (but not C-reactive protein) concentration was significantly associated with self-reported angina pectoris. Neither fibrinogen or C-reactive protein concentrations were significantly associated with angina pectoris when entered in the model simultaneously. C-reactive protein and fibrinogen concentrations were positively associated with myocardial infarction when entered separately into models, but only C-reactive protein concentration was significantly associated with myocardial infarction when both variables were entered simultaneously. These cross-sectional data showed a significant positive association between C-reactive protein concentration and myocardial infarction but not self-reported angina pectoris in the U.S. population.

Rheological influences on thrombosis

Blood flow plays important roles in the localization and morphology of thrombosis within the circulation. Blood flow properties (rheological variables) are associated with thrombotic risk factors and thrombotic risk; conversely their modification may reduce thrombotic risk.

Lipoproteins and the haemostatic system in atherothrombotic disorders

The remarkable extent to which interactions between the plasma lipoproteins, inflammatory factors and the haemostatic system contribute to the response to injury and growth of the plaque in atherosclerosis is being increasingly documented. High plasma concentrations of very-low density (VLDL) and low-density lipoproteins (LDL), together with oxidatively modified LDL and lipoprotein (a), can induce responses in vascular endothelial cells, smooth muscle cells, monocytes/macrophages, platelets, neutrophils and humoral factors that are in a variety of ways both procoagulant and antifibrinolytic. Plasma high-density lipoproteins appear to promote anticoagulant mechanisms. Post-prandial lipaemia is associated with transient changes in factor VII which may be indicative of temporary hypercoagulability. The cellular and humoral effects of LDL and VLDL on the haemostatic system appear to be largely reversible, which may help to explain the prompt improvement in the atherothrombotic state gained by correction of hyperlipidaemia.

Plasma fibrinogen and incident hypertension in the Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND

Several cross-sectional studies have reported a positive association between plasma fibrinogen levels and prevalent hypertension. Other studies have reported a positive association between hypertension and whole-blood or plasma viscosity, to which fibrinogen contributes. To our knowledge, there has been no prospective study of fibrinogen and incident hypertension.

SUBJECTS AND METHODS

We measured plasma fibrinogen levels in a population-based cohort study of middle-aged adults and related it to the occurrence of incident hypertension (systolic blood pressure > or = 140 mmHg or diastolic blood pressure > or = 90 mmHg or use of antihypertensive medication) over 6 years.

RESULTS

There was a moderately strong positive association between fibrinogen levels and prevalent hypertension in both men and women, with the odds of hypertension elevated by 50% for the highest fibrinogen quartile versus the lowest. Among 7884 participants at risk, 1609 developed hypertension over 6 years. Adjusted for age, race, field center and baseline systolic blood pressure, the odds ratio of incident hypertension in relation to fibrinogen quartiles was 1.0, 1.07, 1.21 and 1.43 in men (P= 0.003 for trend) and 1.0, 0.92, 0.99 and 0.99 in women (P= 0.89 for trend). After adjustment for other risk factors, the odds ratios were 1.0, 1.03, 1.15 and 1.29 (P= 0.045 for trend) in men and remained nonsignificant in women.

CONCLUSIONS

Despite a moderately strong positive association between fibrinogen levels and prevalent hypertension in both sexes, there was only a weak positive association between fibrinogen levels and incident hypertension in men and no association in women. Whether an elevated fibrinogen level is a risk factor for, or a consequence of, hypertension remains unclear.

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.

von Willebrand factor, fibrinogen and other plasma proteins as determinants of plasma viscosity

Plasma viscosity and fibrinogen are risk factors for cardiovascular disease and on rheological grounds, it is widely believed that the latter is a major determinant of the former. However, other plasma constituents may also be important determinants of plasma viscosity. Our aim was to determine whether or not levels of von Willebrand factor contributed to plasma viscosity. We measured plasma viscosity, fibrinogen, von Willebrand factor, immunoglobulins G, A and M, total, HDL- and LDL-cholesterol, triglycerides and albumin in 95 patients with peripheral arterial disease and in 120 healthy controls. A stepwise multivariate analysis was performed to determine the major influences of plasma viscosity. We also measured fibrinogen, von Willebrand factor, immunoglobulins G, A and M, total, HDL- and LDL-cholesterol, triglycerides, albumin and viscosity in 32 smokers as they successfully progressed to being non-smokers. The level of von Willebrand factor was an independent influence on plasma viscosity in the controls (P < 0.05), patients (P < 0.01) and in the combined group (P < 0.001). von Willebrand factor, fibrinogen and plasma viscosity, but not the immunoglobulins, lipoproteins or albumin, fell (P < 0.05) in smokers as they became non-smokers. We find that von Willebrand factor contributes to plasma viscosity, hence a reduction in levels of von Willebrand factor should result in a reduction in viscosity. These data may have implications for the pathogenesis of cardiovascular disease.

Relationship between plasma viscosity and the severity of coronary heart disease

Several studies have indicated that plasma viscosity contributes to cardiovascular risk in men. So far, a significant relationship between plasma viscosity and the severity of coronary heart disease has not been found. Thus, the present study is the first to report on the relationship of plasma viscosity and the severity of coronary heart disease. In a collective of 1142 male myocardial infarction patients, plasma viscosity and additional laboratory parameters were determined. Atherosclerotic changes were quantified by coronary angiography. Patients were divided into groups without any, and with one to three stenosed vessels. We found a positive relationship between plasma viscosity and the severity of coronary heart disease, even after adjusting groups for age, fibrinogen, and use of diuretics. Mean plasma viscosity ranged from 1.141+/-0.035 mPa s in patients without stenosed vessels to 1.162+/-0.044 mPa s in patients who had three coronary vessels with stenoses >50%. Differences between the groups were significant (P<0.001 to 0.05), with two exceptions: differences between patients without any and with one stenosed vessel, as well as between patients with one and two stenosed vessels, did not reach the significance level. On the whole, we can give further support to the hypothesis that cardiovascular risk factors and coronary heart disease may be linked by plasma viscosity.

Blood viscosity and elevated carotid intima-media thickness in men and women: the Edinburgh Artery Study

BACKGROUND

Several hemostatic and rheological factors have been associated with incident cardiovascular events. However, there have been no reports on the relationship of rheological factors with early atherosclerosis and very few on hemostatic factors. We therefore studied the relationship between these factors and carotid intima-media thickness (IMT).

METHODS AND RESULTS

The Edinburgh Artery Study measured fibrinogen, tissue plasminogen activator (tPA), fibrin D-dimer, von Willebrand factor (vWF), blood and plasma viscosities, and hematocrit as part of its baseline examination during 1988-1989. At the 5-year follow-up, valid measurements of IMT had been recorded in 1106 men and women 60 to 80 years old. In men, blood viscosity (P< or =.001) and its major determinants, plasma viscosity, fibrinogen (both P< or =.01), and hematocrit (P< or =.05), were all linearly related to IMT. Furthermore, blood viscosity, fibrinogen (both P< or =.01), and plasma viscosity (P< or =.05) remained significantly associated on multivariate analysis. Correcting blood viscosity to a standard hematocrit of 45% had little effect on its association. In men, there was a significantly increased risk of having an IMT above versus below the upper quartile of its distribution (1.05 mm) for SD increases in blood viscosity (P< or =.01), fibrinogen, corrected blood viscosity, and plasma viscosity (all P< or =.05). With the exception of plasma viscosity, these risks were unaffected by adjustment for other common cardiovascular risk factors. No significant associations were found between any of the hemorheological factors and IMT in women or for tPA, fibrin D-dimer, or vWF in either sex.

CONCLUSIONS

These findings suggest that in men, blood viscosity and its major determinants are associated not only with incident cardiovascular events but also with the early stages of atherosclerosis. This may be one explanation for the link between rheological factors and events.

Liposuction in Dercum's disease: impact on haemostatic factors associated with cardiovascular disease and insulin sensitivity

OBJECTIVE

To study the impact of adipose tissue removal by liposuction on factors associated with increased risk of cardiovascular atherosclerotic disease within the coagulation and fibrinolytic system and glucose metabolism.

DESIGN, SETTING AND SUBJECTS

Liposuction was performed in 53 patients with Dercum's disease. The levels of fibrinogen, von Willebrand factor antigen (VWF:Ag) and plasminogen activator inhibitor type 1 activity (PAI-1) were measured preoperatively, and 2 weeks, 4 weeks and 3 months postoperatively. In a subsample of 10 patients, insulin sensitivity was determined before and 2-4 weeks after surgery using the 2-h euglycaemic hyperinsulinaemic clamp technique. The study was performed as a single-centre study.

MAIN OUTCOME MEASURE

Fibrinogen, PAI-1 and VWF:Ag levels, and glucose uptake before and after removal of adipose tissue.

RESULTS

Weight reduction was sustained throughout the follow-up period with a mean decrease from 90.7 to 86.6 kg (P < 0.0001). There was a slight increase in levels of coagulation factors 2 and 4 weeks postoperatively, probably in reaction to the surgical trauma. After 3 months the values had returned to preoperative levels except for PAI-1, which still showed a slight increase (P < 0.05). In the subsample of 10 patients, glucose uptake was improved (P < 0.05) from a short-term perspective after surgery.

CONCLUSION

Surgical removal of adipose tissue, without change in lifestyle, does not seem to improve the levels of coagulation and fibrinolytic factors associated with cardiovascular atherosclerotic disease, whereas glucose takeup may be facilitated and insulin sensitivity increases from a short-term perspective.

Hemostatic factors as predictors of ischemic heart disease and stroke in the Edinburgh Artery Study

Plasma fibrinogen is a consistent predictor of ischemic heart disease (IHD) in prospective studies, but there are fewer data relating other hemostatic variables to IHD and also to stroke. We therefore studied the relationships of plasma fibrinogen, von Willebrand factor antigen, tissue plasminogen activator (TPA) antigen, factor VII, and fibrin D-dimer to incidence of IHD and stroke and determined whether any associations could be explained by conventional risk factors and baseline heart disease. In the Edinburgh Artery study, 1592 men and women aged 55 to 74 years, randomly sampled from the general population, were followed prospectively over 5 years to detect fatal and nonfatal IHD and stroke events. During the 5 years, 268 new vascular events were identified. Baseline plasma fibrinogen was independently related to risk of stroke in multivariate analysis that adjusted for cigarette smoking, LDL-cholesterol, systolic blood pressure, and preexisting IHD (relative risk [RR] 1.52, 95% confidence interval [CI] 1.17, 1.98). TPA antigen, and fibrin D-dimer were also independently associated with risk of stroke (RR 1.69,95% CI 1.22,2.35 and RR 1.96, 95% CI 1.12,3.41, respectively). Significant relationships were found between TPA antigen and myocardial infarction (P < or = .05). In older men and women, increased coagulation activity and disturbed fibrinolysis are predictors of future vascular events (both IHD and stroke).