Coagulation system activation and increase of D-dimer levels in peripheral arterial occlusive disease

Paired Analysis of D-Dimer and Its Correlated Hemostatic Parameters in 30 Dogs with Neoplasms after Tumorectomy

Previous studies have reported that dogs with neoplasms had elevated D-dimer levels. However, few studies have addressed whether D-dimer could be an indicator of tumor burden. The clinical significance of paired analysis of pre- and post-operation of D-dimer levels in dogs has rarely been described. The present study investigated the values of D-dimer levels and their correlated hemostatic alterations in dogs with surgically removable benign and malignant tumors. This study analyzed 30 clinically healthy and 30 tumor-bearing dogs and evaluated the hemostatic functions including D-dimer, thromboelastography G (TEG G), fibrinogen, activated partial thromboplastin time (aPTT), prothrombin time, and platelet count. The median level of pre-treatment D-dimer was 0.8 µg/mL (range: 0.1–6.3 µg/mL), whereas the control dogs exhibited a median value of 0.1 µg/mL (range: 0.1–0.1 µg/mL, p < 0.0001). After tumorectomy, the median levels of D-dimer (p < 0.0001), fibrinogen (p < 0.0001), TEG G value (p < 0.01), and aPTT (p < 0.05) were significantly lower than those of the pre-treatment samples. However, further studies are needed to clarify the values of other hemostatic evaluations. The study revealed the clinical significance of D-dimer and its correlated hemostatic parameters by paired analysis in dogs with tumors. Though more cases are needed for solid confirmation, these values could be potential tumor biomarkers for dogs.

Potential clinical utility of plasma D-dimer levels among women with cervical cancer in Lagos, Nigeria

The link between plasma D-dimer levels and underlying malignancy has been established. How this translates in clinical practice as a marker of detection and prognosis of cervical cancer (CC) is still unknown. This study compared the plasma D-dimer levels in women with and without CC and assessed the associations between plasma D-dimer levels and the stage and grade of CC. It was a comparative cross-sectional study of 65 women with histological diagnosis of CC and an equal number of age-matched cancer-free women enrolled at the University Teaching Hospital in Lagos, Nigeria. Participants' sociodemographic and clinical data as well as venous blood samples for estimation of plasma D-dimer were collected for statistical analyses. A receiver operating characteristic (ROC) analysis is performed to select the cut-off value of plasma D-dimer for differentiating CC from non-cancer. There was a statistically significant difference in the median levels of plasma D-dimer of women with CC and their cancer-free comparison groups (3,120 (1,189-4,515) versus 210 (125-350) ng/mL; p = 0.001). A plasma D-dimer value of 543 ng/mL was chosen in a ROC analysis as the discriminatory cut-off to differentiate CC from non-cancer. There were significant associations between plasma D-dimer levels and the International Federation of Gynaecology and Obstetrics stage (p = 0.001) or grade (p = 0.001) of CC. The study, therefore, demonstrated the potential clinical usefulness of plasma D-dimer as a diagnostic and prognostic marker of CC.

Incidence of pulmonary embolism and impact on mortality in patients with malignant melanoma

PURPOSE

Pulmonary embolism (PE) occurs frequently in patients with malignant melanoma (MM). The aim of this study is to determine the incidence of PE in patients with MM and to assess the clinical characteristics and mortality of MM patients with PE.

MATERIAL AND METHODS

Medical records from 381 MM patients who underwent contrast-enhanced computed tomography were evaluated. Imaging parameters including location of PE and measurements of right heart dysfunction and clinical parameters including D-Dimer levels, local and distant tumor stage and time of death were analyzed.

RESULTS

PE was found in 23/381 (6%) MM patients, whereby 17/23 (74%) were detected incidentally and only 6/23 (26%) were symptomatic. The presence of PE significantly correlated with elevated D-Dimers (p < 0.001), right ventricular dysfunction (p = 0.04), higher local tumor stage (≥T3) (p = 0.05), presence of visceral (p = 0.02) or cerebral metastases (p = 0.03) and increased mortality (p = 0.05). Further, patients with central PE showed an increased mortality compared to peripheral PE (p = 0.03), but no correlation was found between the localization of PE and the occurrence of clinical symptoms (p = 0.36).

CONCLUSION

PE in patients with MM often occurs without clinical symptoms and is indicative for advanced disease and a poorer prognosis.

Prognostic value of pretreatment plasma D-dimer level in dogs with intermediate to high-grade non-Hodgkin lymphoma

Pretreatment D-dimer levels have been reported to predict survival in several types of malignancies in human patients. The objective of this study was to evaluate the prognostic value of pretreatment D-dimer level in dogs with intermediate to high-grade non-Hodgkin lymphoma (NHL). In a prospective, randomized, double-blind study of F14512 vs etoposide phosphate, we assessed the prognostic value of pretreatment plasma D-dimer level in 48 client-owned dogs diagnosed with intermediate to high-grade NHL. The correlation between pretreatment plasma D-dimer level and various clinical features, progression-free survival (PFS) and overall survival (OS) was analysed. The median value of pretreatment plasma D-dimer level was 0.4 μg/mL (range: 0.1-14.3 μg/mL). High pretreatment plasma D-dimer level (>0.5 μg/mL) was detected in 44% (21/48) of dogs. High D-dimer levels were not correlated with naive vs relapsed lymphoma, clinical stage, substage, immunophenotype or treatment group. D-dimer levels >0.5 μg/mL were significantly associated with inferior median PFS (54 vs 104 days, P = .011) and OS (93 vs 169 days, P = .003). In the multivariate analysis, high D-dimer levels remained an independent predictor for worse PFS (HR: 3.21, 95% CI: 1.57-6.56, P = .001) and OS (HR: 3.87, 95% CI: 1.88-7.98; P < .001). This study suggests that pretreatment plasma D-dimer level can serve as a predictor of prognosis in dogs with intermediate to high-grade NHL. Further studies are warranted to confirm these findings.

A combined marker based on plasma D-dimer and serum albumin levels in patients with nasopharyngeal carcinoma is associated with poor survival outcomes in a retrospective cohort study

Background: Activation of the clotting-fibrinolytic system in cancer patients is common and results in an unfavorable clinical outcome. This study aimed to investigate the role of pretreatment plasma D-dimer levels and the combination of D-dimer and albumin (DA) on the prediction of survival prognosis in patients with nasopharyngeal carcinoma (NPC). Methods: The study comprised 511 patients with NPC. Pretreatment plasma D-dimer and serum albumin levels were measured. DA was classified as a new biomarker where D-dimer and albumin levels were combined and was grouped by the cutoff value of both. The correlations of plasma D-dimer levels with clinicopathological features and survival outcome were calculated using the Chi-square test. Kaplan-Meier estimates were performed to analyze the survival functions and were compared using log-rank tests. Cox proportional hazard regression analysis was used to assess the effects of D-dimer and DA on distant overall survival (OS) and distant metastasis-free survival (DMFS). Results: The median follow-up period was 45.2 months (range 2.1-79.8). Elevated plasma D-dimer levels were positively associated with age at diagnosis (P = 0.034), platelet levels (P = 0.043), and Epstein Barr Virus (EBV) DNA copy number (P = 0.035). Additionally, multivariate analysis demonstrated that elevated plasma D-dimer levels were strongly associated with a poorer OS (HR 2.074, 95% CI 1.190-3.612, P = 0.010), but not DMFS. After adjustment for other variables, DA stratification acted as an independent prognostic marker for OS (P = 0.038) and DMFS (P = 0.031) in patients with NPC, when combined with albumin levels. Conclusions: Increased plasma D-dimer levels accurately predict poor OS and may be an effective independent prognostic factor in patients with NPC. Moreover, in conjunction with serum albumin, DA may serve as a factor in predicting OS and DMFS.

D-dimers in malignant melanoma: Association with prognosis and dynamic variation in disease progress

Malignant cells elicit a chronic hemostatic activation in disease progress. This procoagulant activity does not only bear a risk for thromboembolism but also facilitates tumor growth and dissemination. An elevated plasma D-dimer level indicates an activated coagulation and fibrinolysis. In this study, the association of D-dimer levels with clinicopathological parameters and patients outcome in melanoma was investigated analyzing in total 533 melanoma patients retrospectively. Using the cut-off point of 0.6 mg/L D-dimer 145 of the total 533 patients (27.2%) were identified with elevated plasma D-dimer levels. This increased D-dimer level positively correlated with tumor thickness (p = 0.0003), lymph node invasion (p = 0.0004) and metastatic state (p <0.0001). To assess the association of D-dimer levels with progression-free survival (PFS) and overall survival (OS), long-rank test and the Cox proportional hazard model was performed. Univariate analyses revealed that elevated D-dimer levels were significantly associated with decreased PFS (HR:2.89, 95% CI (2.07-7.56), p < 0.0001) and OS (HR:2.22, 95% CI (1.06-4.57), p = 0.035). Moreover, multivariate analyses identified elevated D-dimer levels being associated with poor disease outcome (PFS:HR:2.47, 95% CI (1.23-4.98), p = 0.012; OS:HR:2.01, 95% CI (0.09-4.45), p = 0.087). Additionally, D-dimer levels were significantly increased in terminal stage patients when comparing plasma levels 0-8 versus 24-48 weeks before death (p = 0.0003). In summary, this study presents multiple evidence that elevated D-dimer levels in melanoma patients associate with poor prognosis and therefore plasma levels of D-dimers could reveal a more aggressive phenotype of melanoma and may guide the management of anti-melanoma treatment including the concept of an anti-coagulatory therapy in tumor patients.

The effect of exercise on coagulation and fibrinolysis factors in patients with peripheral arterial disease

Peripheral arterial disease is a widely prevalent atherosclerotic occlusive disorder. Symptoms commence with exercise-induced pain in the lower extremities, known as claudication. Despite the fact that exercise has been shown to improve fibrinolytic profile some patients, the effect of exercise on coagulation and fibrinolysis cascades in claudicants has not been comprehensively defined. Literature search in English language yielded 13 studies of exercise on claudicants, including 420 patients. Claudicants tend to have a higher coagulation activity at rest compared to healthy individuals, a trend that persists even after exercise. Post-exercise coagulation activity of claudicants is increased when compared to their respective baseline levels, but it is so in a non-consistent manner. From the available data, it has been suggested that claudicants have a functional and effective fibrinolytic mechanism in place, operating continuously at a relatively higher activity level compared to healthy individuals. Fibrinolysis seems to be activated by exercise; a positive outcome with a prolonged effect as shown by a few of the studies. A final conclusion whether coagulation or fibrinolysis activity is affected mostly by exercise type and intensity in claudicants could not be answered. All conclusions regarding the effect of exercise on the coagulation and fibrinolysis mechanisms should be taken under cautious consideration, due to the limited number of studies, the small number of patients and the different exercise strategies employed in each study. Further randomized studies with similar exercise protocols could provide safer conclusions in the future.

Venous and Arterial Thrombosis: Is There a Link?

An increasing body of evidence suggests the likelihood of a link between venous and arterial thrombosis. The two vascular complications share several risk factors, such as age, obesity, smoking, diabetes mellitus, blood hypertension, hypertriglyceridemia, and metabolic syndrome. Moreover, there are many examples of conditions accounting for both venous and arterial thrombosis, such as the antiphospholipid antibody syndrome, hyperhomocysteinemia, malignancies, infections, and the use of hormonal treatment. Finally, several recent studies have consistently shown that patients with venous thromboembolism are at a higher risk of arterial thrombotic complications than matched control individuals. We, therefore, speculate the two vascular complications are simultaneously triggered by biological stimuli responsible for activating coagulation and inflammatory pathways in both the arterial and the venous system. Future studies are needed to clarify the nature of this association, to assess its extent, and to evaluate its implications for clinical practice.

Pretreatment plasma D-dimer, fibrinogen, and platelet levels significantly impact prognosis in patients with epithelial ovarian cancer independently of venous thromboembolism

OBJECTIVE

The study aimed to evaluate the prognostic value of pretreatment plasma dimerized plasmin fragment D (D-dimer), fibrinogen, and platelet levels in epithelial ovarian cancer (EOC) after adjusting for venous thromboembolism (VTE) and to screen out the patients with the greatest risk for poor prognosis.

METHODS

The study comprised 190 patients with EOC. The plasma D-dimer, fibrinogen, and platelet levels were examined before treatment and analyzed with patient clinicopathological parameters, progression-free survival (PFS), and overall survival (OS). The survival analysis was performed using the Kaplan-Meier method, and prognostic factors were assessed using the Cox proportional hazards regression model.

RESULTS

The incidences of elevated plasma D-dimer levels, hyperfibrinogenemia, and thrombocytosis were 40%, 42.11%, and 45.26%, respectively. Elevated plasma D-dimer level, hyperfibrinogenemia, and thrombocytosis were associated with advanced tumor stage (P < 0.001, P = 0.013, P < 0.001). In addition, the elevated plasma D-dimer levels were associated with macroscopic postoperative residual disease (P = 0.002) and VTE events (P = 0.006). In multivariate Cox regression model, plasma D-dimer, fibrinogen, and platelet levels were identified as independent prognostic factors for OS (P = 0.039, P = 0.002, and P = 0.049). However, plasma fibrinogen and platelet levels, but not D-dimer levels, had independent prognostic value for PFS (P = 0.012 and P = 0.022). Patients with at least any 2 abnormalities of plasma D-dimer, fibrinogen, and platelet levels showed shorter PFS and OS than did patients with at most 1 abnormality of 3 parameters (P < 0.001).

CONCLUSIONS

Pretreatment plasma D-dimer, fibrinogen, and platelet levels, which impact prognosis independently of VTE, were demonstrated to be potential markers to predict disease progression and surgery outcome in patients with EOC. The combined use of plasma D-dimer, fibrinogen, and platelet levels may help to identify the high-risk populations for treatment decisions.

Prognostic Significance of Combination of Preoperative Platelet Count and Neutrophil-Lymphocyte Ratio (COP-NLR) in Patients with Non-Small Cell Lung Cancer: Based on a Large Cohort Study

Introduction

The aim of this study was to investigate the prognostic significance of the combination of the preoperative platelet count and neutrophil-lymphocyte ratio (COP-NLR) for predicting postoperative survival of patients undergoing complete resection for non-small cell lung cancer (NSCLC).

Methods

The preoperative COP-NLR was calculated on the basis of data obtained.Patients with both an increased platelet count (>30.0×10⁴ mm^-3) and an elevated NLR (>2.3) were assigned a score of 2, and patients with one or neither were assigned as a score of 1 or 0, respectively.

Results

A total of 1238 NSCLC patients were enrolled in this analysis. Multivariate analysis using the 15 clinicolaboratory variables selected by univariate analyses demonstrated that the preoperative COP-NLR was an independent prognostic factor for DFS (HR: 1.834, 95%CI: 1.536 to 2.200, P<0.001) and OS (HR: 1.810, 95%CI: 1.587 to 2.056, P<0.001). In sub-analyses by tumor stage (I, II, IIIA), a significant association was found between DFS and OS and level of COP-NLR in each subgroup (P<0.001, P=0.002, P<0.001 for DFS, respectively; P<0.001, P=0.001, P<0.001 for OS). When the subgroup of patients with high-risk COP-NLR (score of 2) was analyzed, no benefit of adjuvant chemotherapy could be found (P=0.237 for DFS and P=0.165 for OS).

Conclusions

The preoperative COP-NLR is able to predict the prognosis of patients with NSCLC and divide these patients into three independent groups before surgery. Our results also demonstrate that high-risk patients based on the COP-NLR do not benefit from adjuvant chemotherapy. Independent validation of our findings is warranted.

Predictive value of plasma D-dimer levels in patients with advanced non-small-cell lung cancer

Purpose

The relationship between plasma D-dimer level and the prognosis of advanced non-small-cell lung cancer (NSCLC) is not well studied. This study investigated the role of plasma D-dimer as a prognostic factor in advanced NSCLC.

Methods

The plasma D-dimer was measured in 1,931 newly diagnosed advanced NSCLC patients by enzyme-linked immunosorbent assay. Correlations between plasma D-dimer levels and other clinical parameters were analyzed. Survival curves were plotted using the Kaplan–Meier method. The Cox proportional hazard model was used for multivariate analysis.

Results

Plasma D-dimer concentrations were within the normal range in 1,393 patients (72.1%) and elevated in 538 patients (27.9%). The median overall survival was 11.5 and 8.8 months in the normal and high plasma D-dimer group, respectively (P<0.001). The progression-free survival of first-line chemotherapy was 5.0 months and 4.4 months in the groups with normal and high levels of plasma D-dimer, respectively, (P<0.001). By multivariate analyses, the elevated plasma D-dimer level was found to be an independent prognostic factor for poor survival (hazard ratio =1.245; P<0.001).

Conclusion

Plasma D-dimer is an independent determinant of poor prognosis in advanced NSCLC.

Microparticle-associated tissue factor activity in patients with pancreatic cancer: correlation with clinicopathological features

BACKGROUND

Patients with pancreatic cancer have an unfavourable prognosis. A central role in pancreatic cancer progression has been suggested for tissue factor (TF), the main initiator of the blood coagulation cascade. We hypothesized that elevated levels of plasma microparticle (MP)-associated TF activity might indicate the presence of poorly differentiated pancreatic cancer, disease dissemination and infiltration of peripancreatic vessels.

METHODS

MP-TF activity was measured in 73 pancreatic cancer patients and 22 healthy controls. Abdominal computerized tomography (CT) scans performed at study inclusion were investigated for probability of tumoural vascular invasion. In addition, intratumoural TF expression, D-dimer and CA 19-9 levels were determined.

RESULTS

MP-TF activity (pg/mL) was significantly higher in patients (median: 0·37 [range: 0·00-11·91]) than in controls (median: 0·05 [range: 0·00-0·76]; P < 0·001). When pancreatic cancer patients were compared with regard to stage and grade, significantly elevated levels of MP-TF activity were only present in those with poorly differentiated metastatic nonresectable tumours (n = 11, median: 2·95 [range: 0·25-11·91]). In three patients with poorly differentiated tumours, a high probability of vascular invasion was found (MP-TF activity in these cases: 2·95, 7·00 and 10·34). MP-TF activity correlated strongly with CA 19-9 (r = 0·60) and weakly with D-dimer (r = 0·33) levels. Immunohistochemical staining for TF was positive in 14 of 15 resected tumours. MP-TF activity was associated with an increased risk of mortality (HR: 1·8 per doubling in MP-TF activity, [95% CI: 1·4-2·4, P < 0·001]).

CONCLUSION

MP-TF activity might represent a biomarker for a poorly differentiated and invasive pancreatic cancer phenotype and poor survival.

Prognostic significance of elevated D-dimer for survival in patients with sarcoma

BACKGROUND

Elevated levels of D-dimer, a marker for the systemic activation of the clotting and fibrinolysis, are frequently observed in patients with venous thromboembolism (VTE) and malignancy. We examined the prognostic significance of baseline plasma D-dimer levels for predicting survival in sarcoma.

METHODS

The study comprised of 45 patients receiving first-line chemotherapy for inoperable, high-risk for relapse, or metastatic disease. Plasma D-dimer levels was measured before chemotherapy. Univariate and multivariate analysis were performed for association between plasma D-dimer levels and baseline clinical characteristics in predicting survival.

RESULTS

D-dimer levels were elevated to ≥500 ng/mL in 53% (24 of 45 patients). Six of 45 patients (13%) developed VTE. The Kaplan-Meier analysis showed that the median survival for patients with VTE, metastatic disease, progression on chemotherapy, or D-dimer ≥500 ng/mL was shorter (log-rank test, P=0.012, 0.001, 0.034, and 0.015, respectively). The mortality rate for patients with D-dimer ≥500 ng/mL was higher (P<0.0001) than those with <500 ng/ml for both metastatic (100% vs. 62.5%) and nonmetastatic (58% vs. 31%) groups [median follow-up; 60 mo (range, 9 to 106 mo)]. Using stepwise proportional hazard model, D-dimer levels and metastasis status were independent significant predictors for survival [hazard ratios (95% confidence intervals), 4.24 (1.88-9.60), and 3.28 (1.42-7.58), respectively].

CONCLUSIONS

Elevated D-dimer levels have independent significant prognostic value for survival in sarcoma patients with both metastatic and nonmetastatic disease and may help identify high-risk patients for treatment decisions.

Prothrombin fragments in cardiovascular disease

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

Intima-media thickness of common carotid and brachial arteries and prothrombin fragment 1 + 2 are associated with left ventricular diastolic dysfunction in patients with myocardial infarction

AIMS

To investigate the association between intima-media thickness of brachial and common carotid arteries and factors of the coagulation- and fibrinolysis-system with left ventricular diastolic dysfunction in patients with a previous myocardial infarction.

PATIENTS AND METHODS

One hundred and twenty three patients, men (76%) and women (24%) aged between 32 and 81 years with a history of previous acute myocardial infarction were included. B-mode ultrasound of common carotid and brachial arteries and echocardiography with tissue Doppler imaging (TDI) were evaluated. Factors of the coagulation- and fibrinolysis-system were also measured.

RESULTS

In patients with previous myocardial infarction, late diastolic filling time was significantly and positively associated with log Prothrombin fragment 1 + 2 (P < 0.001) and with calculated intima-media area (cIMa) of the both common carotid and brachial arteries (P < 0.05). Mitral early-to-late flow velocity ratio (E/A) was significantly and negatively associated with log Prothrombin fragment 1 + 2 (P < 0.001), total cholesterol and cIMa of the both common carotid and brachial arteries (P < 0.05). Moreover both late diastolic filling time and mitral E/A correlated significantly with age and systolic blood pressure. In stepwise multiple regression analysis, log Prothrombin fragment 1 + 2 remained the only variable with independent significant correlation to late diastolic filling time and mitral E/A.

CONCLUSIONS

In a population sample of patients with myocardial infarction, late diastolic filling time and mitral E/A were associated with cIMa of common carotid and brachial arteries, systolic blood pressure, and prothrombin fragment 1 + 2, suggesting a relationship between diastolic dysfunction, thrombin generation and atherosclerosis.

Protein Z-dependent protease inhibitor and protein Z in peripheral arterial disease patients

SUMMARY INTRODUCTION

Protein Z is a vitamin K-dependent protein that serves as a cofactor for the inhibition of activated factor X by the serpin protein Z-dependent protease inhibitor (ZPI). Protein Z plasma levels have been shown to be reduced in patients with peripheral arterial disease (PAD), but ZPI levels have not yet been reported. The aim of this study was to more fully assess the protein Z-ZPI system in individuals with atherosclerosis selected by the presence of symptomatic PAD.

MATERIALS AND METHODS

Protein Z and ZPI levels were determined in 95 PAD patients (73 males; 22 females) [median age: 73 years (range, 50-86 years)] and in 190 controls comparable for age and gender. Protein Z was measured using a commercial immunoassay, and ZPI was measured with a homemade immunoassay and a functional assay.

RESULTS

Protein Z antigen, ZPI antigen and ZPI function were found to be significantly lower in PAD patients with respect to controls [protein Z, median 72.5% (range: 3.4-123.7%) vs. 90.7% (range: 32.1-203.2%), P < 0.0001; ZPI antigen, 86.1% (range: 25.1-149.5%) vs. 93.2% (range: 48.9-171.3%), P = 0.004; ZPI function, 83.5% (range: 21.1-135.2%) vs. 97.2% (range: 50.5-175.5%), P < 0.0001]. The lowest tertiles of protein Z antigen [odds ratio (OR) 5.4, 95% confidence interval (CI) 2.2-13.5, P < 0.0001] and ZPI function (OR 2.4, 95% CI 1.1-5.5, P = 0.03) were associated with PAD on multivariate analysis after adjustment for age, gender, and traditional cardiovascular risk factors. A significant inverse relationship was also observed between protein Z and ZPI levels and the number of traditional cardiovascular risk factors and the clinical severity of disease (Fontaine stage).

CONCLUSIONS

Low levels of protein Z antigen and protein Z activity are significantly associated with the occurrence and severity of atherosclerotic PAD.

African-American ethnicity is associated with higher plasma levels of D-dimer in adults with hypertension

BACKGROUND

African Americans with hypertension have higher cardiovascular morbidity and mortality than hypertensives from other ethnic groups. Plasma D-dimer, a fragment generated from fibrin during lysis of mature clot in vivo, is a predictor of adverse cardiovascular events.

OBJECTIVE

We investigated whether plasma levels of D-dimer differ between African American (AA) and non-Hispanic white (NHW) adults with hypertension.

METHODS

Participants included 933 AA (65 +/- 9 years, 72% women) and 821 NHW (61 +/- 9 years, 56% women) from the community. D-dimer was measured using an immunoturbidimetric assay. Multivariable regression analyses, stratified by gender, were performed to assess whether AA ethnicity was associated with D-dimer levels after adjustment for age, body mass index (BMI), total and high-density lipoprotein (HDL) cholesterol, systolic blood pressure, diabetes, history of smoking, medication (statin and aspirin) use, lifestyle variables (physical activity, alcohol intake, and education), estimated glomerular filtration rate (eGFR), and a marker of inflammation, C-reactive protein (CRP).

RESULTS

D-dimer levels were higher in AA men and women than in their NHW counterparts (mean +/- SD; men 256 +/- 199 vs. 190 +/- 183 ng mL(-1), P < 0.001; women, 290 +/- 233 vs. 225 +/- 195 ng mL(-1), P < 0.001). In both sexes, after adjustment for age, conventional risk factors, medication use, and lifestyle variables, AA ethnicity remained associated with higher D-dimer levels (P = 0.002 in men, P = 0.006 in women). These associations remained significant after additional adjustment for eGFR and plasma CRP (P = 0.003 in men, P < 0.0001 in women).

CONCLUSIONS

Among adults with hypertension, AA ethnicity was independently associated with higher plasma levels of D-dimer.

Links between arterial and venous disease

An increasing body of evidence suggests the likelihood of a link between arterial and venous disease. According to the results of recent studies, atherosclerosis and venous thromboembolism (VTE) share common risk factors, including age, obesity, diabetes mellitus and metabolic syndrome. Atherosclerosis has the potential to promote the development of thrombotic disorders in the venous system. Another scenario assumes that the two clinical conditions are simultaneously triggered by biological stimuli responsible for activating coagulation and inflammatory pathways in both the arterial and the venous system. Several recent studies have consistently shown that patients with VTE of unknown origin are at a higher risk of cardiovascular diseases, including atherosclerotic complications, than patients with secondary VTE and matched control individuals. Future studies are needed to clarify the nature of this association, to assess its extent and to evaluate its implications for clinical practice.

Venous thromboembolism and atherosclerosis: is there a link?

After the initial demonstration provided 4 years ago by a case-control study in the New England Journal of Medicine, numerous investigations have addressed the association between venous and arterial thrombotic disorders. According to the results of recent studies, the two conditions are likely to share common risk factors, including age, obesity, cigarette smoking, diabetes mellitus, arterial hypertension, hyperlipemia and metabolic syndrome. The nature of this association is unclear. On the one hand, atherosclerosis has the potential to promote the development of thrombotic disorders in the venous system. On the other hand, the two clinical conditions can be simultaneously triggered by biological stimuli responsible for activating coagulation and inflammatory pathways in both the arterial and the venous system. Based on the results of two population-based studies carried out in the USA, atherosclerosis is unlikely to constitute a risk factor for venous thromboembolic (VTE) disorders. Several recent studies have consistently shown that subjects with VTE of unknown origin are at a higher risk of subsequent arterial cardiovascular events than subjects with secondary VTE and matched control individuals. In conclusion, the separate nature of arterial and venous disorders has been challenged. Future studies are needed to clarify the nature of this association, to assess its extent, and to evaluate its implications for clinical practice.

Prospective study of subclinical atherosclerosis as a risk factor for venous thromboembolism

BACKGROUND

Whether atherosclerotic disease predisposes to venous thrombosis is uncertain.

OBJECTIVE

To determine whether subclinical atherosclerosis, manifested as increased carotid intima-media thickness (IMT) or presence of carotid plaque, is associated with increased incidence of venous thromboembolism (VTE).

PATIENTS AND METHODS

The Atherosclerosis Risk in Communities study is a prospective cohort of adults aged 45-64 years, examined at baseline (1987-89) and followed for cardiovascular events. Bilateral carotid ultrasound for IMT measurements was done at baseline for portions of the common and internal carotid arteries, and carotid bifurcation and also to detect the presence of carotid plaque. Exclusion criteria included baseline anticoagulant use, history of coronary heart disease, stroke, or VTE, and incomplete data. First VTE during follow-up was validated using abstracted medical records.

RESULTS

Among 13,081 individuals followed for a mean of 12.5 years, 225 first VTE events were identified. Unadjusted hazard ratios (HR) (95% CI) of VTE across quartiles of baseline IMT were 1.0, 1.16 (0.77-1.75), 1.64 (1.12-2.40), and 1.52 (1.03-2.25). However, this association disappeared after adjustment for age, sex, and ethnicity (HRs: 1.0, 1.06, 1.40, and 1.18). Further adjustment for body mass index and diabetes weakened the relative risks even further. Presence of carotid plaque at baseline also was not associated with VTE occurrence; adjusted HR = 0.97, 95% CI = 0.72-1.29.

CONCLUSION

Increased carotid IMT or presence of carotid plaque was not associated with an increased incidence of VTE in this middle-aged cohort, suggesting subclinical atherosclerosis itself is not a VTE risk factor.

Haemostasis, inflammation and renal function following exercise in patients with intermittent claudication on statin and aspirin therapy

Background

Previous studies have suggested that exercise in patients with intermittent claudication (IC) may induce a systemic thrombo-inflammatory response. The effect of secondary prevention therapy on this response is unknown. This study aimed to investigate the effects of treadmill exercise on markers of coagulation activation, inflammation and renal function in patients with IC, receiving aspirin and statin therapy compared to healthy controls.

Methods

Samples were taken before, immediately and 1 hour after exercising on a treadmill in 20 patients with IC and 20 healthy volunteers. Interleukin-6 (IL-6), thrombin-anti-thrombin complex (TAT) and fibrin D-dimer were measured by ELISA. High sensitivity CRP (HsCRP) and urinary albumin were measured via a nephelometric technique, urinary protein via a turbidometric assay and N-acetyl-β-D-glucosaminidase (NAG) via a colorimetric assay.

Results

Elevated baseline levels of Hs-CRP, IL-6, white cell counts, D-dimer and urinary NAG occurred in patients with IC compared to volunteers (p > 0.05). Following exercise there was no increase in Hs CRP or IL-6. D-dimer levels significantly increased following exercise in the patients and volunteers. TAT levels increased immediately after exercise in the patient group only and were significantly increased at 1 hour in both patients and volunteers. A transient rise in the protein creatinine ratio occurred in both groups (p < 0.007), and in albumin creatinine ratio in the patient group. There was no change in urinary NAG.

Conclusion

Elevated markers of inflammation occurred in patients with IC on statin and aspirin therapy but these did not increase following exercise. However, acute exercise resulted in a prothrombotic state evident in both groups, although this was more prolonged in patient with IC. The clinical significance of these findings in patients who are known to be at an increased risk of cardiac and other thrombotic event are unclear.

The constitutive procoagulant and hypofibrinolytic state in patients with intermittent claudication due to infrainguinal disease significantly improves with percutaneous transluminal balloon angioplasty

BACKGROUND

Patients with intermittent lower limb claudication (IC) exhibit a prothrombotic diathesis that is acutely exacerbated by exercise. This may occur because of ischemia/reperfusion injury within the leg muscles during walking and may contribute to the increased risk of thrombotic vascular events in this group of patients. This randomized study compared the effect of lower limb revascularization by percutaneous transluminal balloon angioplasty (PTA), supervised exercise, and best medical therapy (BMT) alone on this prothrombotic state.

METHODS

Twenty-three patients (16 men and 7 women; median age, 67 years; range, 57-77 years) with IC due to infrainguinal disease were randomized to receive BMT alone (n = 7), BMT plus PTA (n = 9), or BMT plus supervised exercise (n = 7) as part of the Health Technology Assessment-funded EXercise vs Angioplasty in Claudication Trial (EXACT). Patients were assessed at baseline and at 3 and 6 months. Thrombin-antithrombin complex (TAT) was determined as a marker of thrombin generation, and plasminogen activator inhibitor (PAI) antigen was determined as a marker of fibrinolysis. Increased TAT indicates a procoagulant state, and increased PAI antigen indicates a hypofibrinolytic state.

RESULTS

At 6 months, subjects randomized to BMT plus PTA demonstrated a significant improvement in ankle-brachial pressure index (P = .013) and maximal walking distance (P = .008), a significant decline in resting thrombin generation (median [interquartile range] TAT, 6.4 microg/L [2.7-13.5 microg/L] to 1.5 microg/L [0.3-2.9 microg/L]; P = .038), and an improvement in resting fibrinolysis (median [interquartile range] PAI-1, 10.0 ng/mL [1.0-20.5 ng/mL] to 1.0 ng/mL [1.0-14.8 ng/mL]; P = .043). There was no significant change in any of these parameters in patients randomized to BMT plus supervised exercise or to BMT alone.

CONCLUSIONS

The addition of lower limb revascularization by PTA to BMT in patients with IC due to infra-inguinal disease results in a medium-term improvement in the resting procoagulant and hypofibrinolytic state. This may translate into a reduction in morbidity and mortality from thrombotic vascular events in this group of patients.

Prothrombin Fragment 1+2 Is Associated With Carotid Intima-Media Thickness in Subjects Free of Clinical Cardiovascular Disease

Background and Purpose— Thrombin, a central enzyme in the clotting cascade, plays a role not only in thrombosis but also in the progression of atherosclerosis. We studied the relationship between prothrombin fragment 1+2 (F1+2), a specific marker of thrombin generation in vivo, and carotid intima-media thickness (IMT), an index of subclinical atherosclerosis.

Methods— We examined 181 asymptomatic middle-aged subjects (mean age 55.6 years, 76.7% men) free of overt clinical atherosclerotic disease. F1+2 was measured by enzyme-linked immunosorbent assay and IMT by duplex ultrasonography of carotid artery. Multiple linear regression analysis was used to assess the relationship between the 2 parameters.

Results— Compared with individuals in the lowest tertile of F1+2, those in the upper tertile (>0.55 nmol/L) showed significantly higher IMT ( P <0.01). In correlation analysis, a positive relationship was found between plasma F1+2 and carotid IMT. F1+2 also correlated positively with cholesterol ( P <0.008) and low-density lipoprotein cholesterol ( P <0.005), but not with blood pressure or body mass index. In the multivariate analysis, the association of F1+2 with carotid IMT remained significant ( P <0.001) after adjustment for age, sex, body mass index, systolic blood pressure, cholesterol, diabetes, and smoking.

Conclusions— In a population sample of adults without clinically overt atherosclerotic disease, the plasma levels of F1+2 were significantly associated with carotid IMT, suggesting a relationship between thrombin generation and the development atherosclerosis.

Exercise-induced changes in coagulation and fibrinolysis in healthy populations and patients with cardiovascular disease

This review highlights the clinical significance of coagulation and fibrinolytic responses, and adaptations in healthy individuals and patients with cardiovascular disease (CVD). Much of the review focuses on indicators of the potential for coagulation and fibrinolysis. The terms 'coagulation potential' and 'fibrinolytic potential' are used frequently, as much of the literature in the area of exercise haemostasis evaluates factors that reflect an increased potential for coagulation, while coagulation per se, may or may not be occurring. Similarly, fibrinolysis is definitively the lysis of inappropriate or excessive blood clot, which may or may not be occurring when the enzymes that stimulate fibrinolysis are activated. Nevertheless, markers of coagulation and fibrinolytic potential are associated with CVD, ischaemic events, and cardiovascular mortality. Additionally, fibrinolytic potential is associated with other established CVD risk factors. Ischaemic events triggered by physical exertion are more likely to occur due to an occlusive thrombus, suggesting the exercise-induced responses related to haemostasis are of clinical significance. The magnitude of increase in coagulation potential, platelet aggregation and fibrinolysis appears to be primarily determined by exercise intensity. Patients with CVD may also have a larger increase in coagulation potential during acute exercise than healthy individuals. Additionally, the magnitude of the fibrinolytic response is largely related to the resting fibrinolytic profile of the individual. In particular, high resting plasminogen activator inhibitor-1 may diminish the magnitude of tissue plasminogen activator response during acute exercise. Therefore, acute responses to exercise may increase the risk of ischaemic event. However, chronic aerobic exercise training may decrease coagulation potential and increase fibrinolytic potential in both healthy individuals and CVD patients. Due to the aforementioned importance of resting fibrinolysis on the fibrinolytic response to exercise, chronic aerobic exercise training may cause favourable adaptations that could contribute to decreased risk for ischaemic event, both at rest and during physical exertion.

Exercise in claudicants is accompanied by excessive thrombin generation

BACKGROUND

exercise in IC leads to ischaemia-reperfusion injury of leg muscles and a systemic inflammatory response, but the effect of on coagulation is unknown.

OBJECTIVE

to compare the effect of exercise on thrombin formation and fibrin turnover in patients with IC (n = 10), and age and sex matched smokers ([S] n = 5) and non-smokers ([NS] n = 5) without peripheral vascular disease.

METHODS

blood was taken from subjects 60 and 30 min before, and 1, 5, 20, 40, 60 and 120 min after, treadmill exercise. Markers of thrombin generation (thrombin-antithrombin complexes [TAT] and prothrombin fragments 1 + 2 [PF1 + 2]) and fibrin turnover (D-dimer and fibrin degradation products [FbDP]) were assayed at each time point.

RESULTS

following exercise, thrombin generation was significantly greater in the claudicant group compared to the control groups (Area Under Curve [AUC] post exercise IC vs S vs NS; TAT 3960 vs 1623 vs 1476 vs = 0.007 Kruskal-Wallis [KW]; PF1 + 2 163 vs 107 vs 123 p = 0.024 KW). Pre and post-exercise, fibrin turnover in claudicants was similar to smoking controls, but higher than non-smoking controls. (AUC post exercise IC vs NS; D-dimer 6340 vs 2754 p = 0.055 Mann-Whitney U[MW]; FbDP 45113 vs 21511 p = 0.009 MW).

CONCLUSION

when compared to non-claudicants, exercise in IC is associated with excessive production of thrombin. Despite this, claudicants have a similar level of fibrin turnover suggesting a possible defect in fibrinolysis. This prothrombotic state may contribute to the excess thrombotic morbidity and mortality suffered by claudicants.

Intravenous prostaglandin E1 reduces soluble vascular cell adhesion molecule-1 in peripheral arterial obstructive disease

OBJECTIVES

Elevated levels of soluble (s) vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1, pointing to activation of cells involved in vascular inflammation, have been previously reported in peripheral arterial obstructive disease (PAOD). We tested the hypothesis that intravenous prostaglandin E(1) (PGE(1)) treatment, which produces clinical benefits in this condition, might decrease such levels.

METHODS

Ten subjects (age range 58 +/- 10 years, 6 male, 4 female) with characterized Fontaine stage IIa to IV PAOD (ankle/arm pressure index <0.96) were entered into a treatment protocol with twice daily intravenous infusions of PGE(1) (alprostadil) at 120 microg per day, repeated for 10 consecutive days. Preinfusion and postinfusion plasma samples were stored for blind enzyme immunoassays of soluble adhesion molecules and the fibrinolytic marker tissue plasminogen activator, type-1 plasminogen-activator inhibitor, and D -dimer.

RESULTS

Estimates of severity of pain at rest, consumption of analgesics, magnitude of trophic lesions, remission to lower Fontaine stages, and favorable changes in the venoarteriolar reflex documented significant beneficial effects of the treatment. Significant (P <.01) pretreatment and posttreatment reductions of in all soluble markers explored were found. Particularly, sVCAM-1 exhibited a significant decrease after each infusion, which was sustained at the last day of treatment (from 854 +/- 214 ng/mL to 775 +/- 215 ng/mL across the first infusion, from 773 +/- 146 ng/mL to 680 +/- 110 ng/mL across the last infusion).

CONCLUSION

Thus a global decrease of vascular cell activation appears to occur as a result of PGE(1) administration and may contribute to the observed clinical benefits in PAOD.

Coagulation, fibrinolysis and platelet P-selectin expression in peripheral vascular disease

OBJECTIVES

to examine coagulation, fibrinolysis, and platelet activity in patients with peripheral vascular disease (PVD).

DESIGN

fifty consecutive PVD patients and 50 healthy volunteers. (Prospective comparative study.)

MATERIALS AND METHODS

P-selectin expression in non-fixed, whole blood was measured flow cytometrically on non-stimulated and ADP- and TRAP-6-stimulated samples. Plasma fibrinogen, von Willebrand factor (vWF), tissue plasminogen activator (tPA), and plasminogen activator inhibitor-1 were determined using standard techniques. Disease severity was stratified on the basis of the ankle-brachial pressure index (ABPI) and the angiographic data were assessed using the Bollinger score.

RESULTS

coagulation and fibrinolysis parameters as well as the P-selectin expression on both stimulated and non-stimulated platelets were significantly increased in patients vs controls (all p<0.01). The respective sensitivity and specificity were as follows: P-selectin expression (81%, 94%), vWF (72%, 86%), fibrinogen (64%, 98%), PAI-1 (44%, 90%), tPA (15%, 100%). P-selectin expression on TRAP-6-stimulated MP correlated with disease severity (r=0.40, p<0.01).

CONCLUSIONS

these findings support the concept of ongoing thrombogenesis in the subclinical progression of PVD and demonstrate the high diagnostic sensitivity of flow cytometric analysis of platelet activation.

Deep venous thrombosis in peripheral vascular disease

BACKGROUND

This prospective study aimed to determine the prevalence of lower limb deep venous thrombosis in patients with peripheral vascular disease (PVD).

METHODS

Some 136 patients admitted for arteriography, angioplasty or arterial reconstruction with limiting claudication (n = 72), ischaemic rest pain (n = 26) or gangrene (n = 38) and 40 control subjects admitted for general surgical procedures but without evidence of PVD were screened with colour duplex ultrasonography for the presence of venous thrombosis in the lower limb deep veins before any surgical or radiological procedures were undertaken. Patient age, the ankle : brachial pressure index (ABPI) and the presence of other risk factors for venous thromboembolism were also recorded.

RESULTS

Venous thrombosis was found in 27 of 136 patients with PVD and two of 40 control patients (P = 0.03). Logistic regression analysis demonstrated that decreasing ABPI independently contributed to an increased risk of deep venous thrombosis.

CONCLUSION

There was a high prevalence of venous thrombosis among patients with PVD which was related to the severity of the ischaemia. Presented to the South West Vascular Surgeons Meeting in Newport, UK, March 1998

Prothrombin fragment 1+2 is a risk factor for myocardial infarction in treated hypertensive men

BACKGROUND

Haemostatic factors may play a part in the development of acute coronary heart disease.

OBJECTIVE

To evaluate as predictors of major coronary events (fatal and non-fatal myocardial infarctions and sudden death) levels of fibrinogen, von Willebrand factor, prothrombin fragment 1+2, thrombin-antithrombin complex, plasminogen activator inhibitor activity and C-reactive protein.

METHODS

We studied 131 men, aged 56-77 years, with treated hypertension and at least one additional cardiovascular risk factor (hypercholesterolaemia, diabetes mellitus or smoking). These patients were recruited from a continuing risk factor intervention study. The mean observation time was 3.0 years.

RESULTS

Fourteen patients died and 16 had a major coronary event during the follow-up period. After adjustments for other risk factors, levels of prothrombin fragment 1+2 and C-reactive protein were independent predictors of major coronary events. The other measured haemostatic variables were not significantly associated with major coronary events during follow-up. Fibrinogen and prothrombin fragment 1+2 levels were independent predictors for mortality.

CONCLUSIONS

Among treated hypertensive men, levels of prothrombin fragment 1+2 and C-reactive protein were independent predictors of major coronary events.

Progressive intermittent claudication is associated with impaired fibrinolysis

PURPOSE

Acute complications of atherosclerosis such as stroke and myocardial infarction are caused by thrombosis and may be associated with impaired fibrinolytic activity. The current study was performed to determine whether peripheral arterial disease (PAD) and its progression are also associated with impaired fibrinolysis, by measurement of tissue plasminogen activator (tPA, the activator of fibrinolysis) and its inhibitor plasminogen activator inhibitor-1 (PAI-1).

METHODS

The study group consisted of 80 men with a mean age of 69 years. This included 18 patients with mild intermittent claudication (MC, pain-free walking distance > or = 200 meters) and 51 patients with severe claudication (SC, walking distance <200 meters). Eleven age- and sex-matched patients without PAD served as controls. All patients had measurements of serum tPA antigen using an enzyme-linked immunoadsorbent assay. Serum levels of tPA and PAI-1 activity were assayed with an amidolytic method. Mean +/- SEM levels of the enzyme levels in patients with progressively more severe PAD were compared with normal controls.

RESULTS

Serum PAI-1 activity levels were significantly elevated in both PAD groups compared with normal controls (p < 0.02). There were no significant differences in the PAI-1 activity levels in groups with worsening degrees of PAD. There was a significant decrease in tPA activity levels in patients with SC (p = 0.01) relative to those with MC and the normal subjects. There was also a significant increase in tPA antigen level in the patients with SC compared with those with MC and the control subjects, as well as a significant inverse correlation between tPA antigen levels and pain-free walking time in patients with claudication (p = 0.001).

CONCLUSIONS

All patients with PAD in this study had significant reductions in endogenous fibrinolytic activity. Patients with SC had more impaired fibrinolytic activity than those with MC and the control subjects, suggesting that the progression to more severe levels of PAD may be associated with worsening endogenous fibrinolysis.

Role of hemostatic risk factors for restenosis in peripheral arterial occlusive disease after transluminal angioplasty

In a prospective study, the role of various hemostatic factors known to be associated with thrombotic risk was investigated in 71 patients with peripheral arterial occlusive disease (PAOD, stages II through IV, Fontaine; aged 68 +/- 13 years). Laboratory investigations were done before; 1, 24, and 48 hours after; and 3 and 6 months after percutaneous transluminal angioplasty (PTA). Thirty of 71 (42.3%) patients developed restenosis (> 50% reduction of the lumen diameter) at the site of PTA within 6 months, verified by color-coded duplex sonography. Significantly increased levels of thrombin-antithrombin III complexes (P < .01), prothrombin fragments 1 + 2 (P < .01), and D-dimers (P < .01) were found 1 hour, as well as 24 to 48 hours, after PTA. Fibrinogen (P < .01) and von Willebrand factor (P < .01) were significantly higher 48 hours after PTA. Restenotic patients as a whole had higher plasma fibrinogen (3.46 +/- 1.12 versus 2.95 +/- 0.62 g/L, P < .01) and C-reactive protein (25.4 +/- 46.7 versus 7.9 +/- 6.9 mg/L, P < .05) at baseline, as well as higher fibrinogen (P < .05) and prothrombin fragments 1 + 2 (P < .01) during months 3 to 6 after PTA. There was a nonsignificant tendency for higher values of von Willebrand factor (206 +/- 98% versus 184 +/- 100%, P = .2) at baseline in patients with restenosis, whereas tissue plasminogen activator, plasminogen activator inhibitor, coagulation screening tests, blood cell counts, and serum lipids showed no significant difference between the two groups. The relative risk for developing restenosis within 6 months while having high fibrinogen (> 2.8 g/L) or C-reactive protein at baseline was 2.80 (95% CI: 1.30-6.02, P < .01) and 1.96 (95% CI: 1.07-3.58, P < .05), respectively. Patients with critical limb ischemia (stage III/IV, Fontaine) had significantly higher fibrinogen and von Willebrand factor at repeated points of time, as well as significantly higher C-reactive protein and lower creatinine clearance at entry. In the logistic regression risk factor analysis, baseline plasma fibrinogen, C-reactive protein concentration, and the severity of the arterial disease were significantly predictive of restenosis. Our results indicate that high procoagulant factors and persistent thrombin generation of the hemostatic system might promote restenosis, particularly in patients with extended atherosclerosis. This finding suggests that new treatment strategies should be taken under consideration for patients with PAOD and PTA.

Correlates of thrombin markers in an elderly cohort free of clinical cardiovascular disease

Studies suggest that thrombosis is important in the progression of atherosclerotic lesions. The biochemical markers prothrombin fragment 1-2 and fibrinopeptide A reflect in vivo thrombin generation and activity, respectively. As such, they are markers that might be associated with cardiovascular risk. From the Cardiovascular Health Study, a cohort study of 5201 persons over 65 years of age, 399 persons free of clinical cardiovascular disease (CVD) at the baseline examination were selected for study of specialized markers of hemostasis. We report the cross-sectional relationships of the thrombin markers to CVD risk factors and measures of subclinical CVD. The range of fragment 1-2 2 was 0.12 to 0.85 nmol/L. The range of fibrinopeptide A was 0.9 to 44.1 micrograms/L. High levels of fragment 1-2 and fibrinopeptide A were associated with age, with levels higher in women than men. Fragment 1-2 was associated with smoking; high levels of triglyceride, creatinine, and C-reactive protein; and low levels of glucose. Fibrinopeptide A was associated with high C-reactive protein and apolipoprotein(a) and lower ankle-brachial index. There were no significant associations of the thrombin markers with race, fibrinogen, alcohol consumption, diabetes, or most measures of subclinical CVD. Study findings support a hypothesis that there are physiological interrelationships between cardiac risk factors, hemostasis, inflammation, and progression of atherosclerosis.

Increased platelet and coagulatory activity indicate ongoing thrombogenesis in peripheral arterial disease

In peripheral arterial disease (PAD) risk of thrombosis is high and systemic haemostatic derangement thought contributory. We investigated platelet and coagulatory activity in patients with PAD and sought to find the best disease indicator. Stagnation point flow adhesion-aggregometry (SPAA) enables real-time quantitative assessment of platelet adhesion and aggregation under well-defined flow conditions. SPAA and agonist-induced aggregometry (Born method) were performed and concentrations of fibrinogen, fibrin monomer (FM), D-dimer, and thrombin-antithrombin complex (TAT) measured in 92 PAD patients and 70 healthy volunteers. Agonist-induced aggregometry detected no differences between patients and controls. SPAA-measured platelet adhesion and spontaneous aggregation (p < 0.001), and concentrations of fibrinogen (p < 0.001), FM (p < 0.001), TAT (p < 0.02) and D-dimer (p < 0.001) were all significantly increased in patients. Neither platelet function nor coagulatory activity was altered in patients receiving aspirin. Sensitivity and specificity in detecting PAD were as follows: SPAA (95%, 93%), fibrinogen (36%, 91%), FM (48%, 84%), TAT (36%, 78%), D-dimer (73%, 80%). Our findings support the concept of ongoing thrombogenesis as being contributory to the progression and possibly to the initiation of PAD. Aspirin alone did not prevent haemostatic hyperreactivity in these patients and flow-mediated platelet function was the most sensitive and specific indicator of advanced disease. This technique thus appears to be valuable, not only for evaluating therapeutic strategies to prevent platelet activation, but also in elaborating platelet-related mechanisms involved in thrombogenesis and atheroma formation.

Influence of blockade at specific levels of the coagulation cascade on restenosis in a rabbit atherosclerotic femoral artery injury model

BACKGROUND

The relation among the coagulation cascade, its individual proteins, and the response to vascular injury is largely undefined. We have evaluated the effect of four probes that block specific levels of coagulation cascade on neointimal hyperplasia in the atherosclerotic rabbit arterial injury model.

METHODS AND RESULTS

Focal femoral atherosclerosis was induced by air-desiccation injury and hypercholesterolemic diet in 48 New Zealand White rabbits, followed by balloon angioplasty. Active-site inactivated factor VIIa (DEGR-VIIa), which blocks the binding of factor VIIa to tissue factor, was administered (n = 12 arteries) by intravenous bolus (1 mg/kg) at the time of balloon angioplasty and followed by infusion of 50 micrograms.kg-1.h-1 for 3 days; for the control (n = 13 arteries), 150 U heparin was injected as bolus and followed by infusion of saline at 50 microL.kg-1.min-1. Recombinant tissue factor pathway inhibitor (TFPI), which binds factor Xa and inhibits the tissue factor-factor VIIa complex and factor Xa, was given as a 1 mg/kg bolus followed by 15 micrograms.kg-1.min-1 infusion for 3 days (n = 17 arteries). Recombinant tick anticoagulant peptide (TAP; n = 15 arteries) and hirudin (n = 14 arteries), which block factor Xa and thrombin, respectively, were administered as a 1 mg/kg bolus followed by 5 micrograms.kg-1.min-1 infusion for 3 days. These three groups had their own controls (n = 14 arteries). There were no differences among treatment groups in preangioplasty and postangioplasty minimal luminal diameter (MLD) by angiography. The mean MLD 21 days after balloon angioplasty was significantly different between control and DEGR-VIIa-treated groups (0.74 +/- 0.25 and 1.24 +/- 0.27 mm, respectively; P = .0001) and between the TFPI-treated group and others (0.88 +/- 0.21 mm for control, 0.97 +/- 0.22 mm for hirudin-treated, 0.98 +/- 0.14 mm for TAP-treated, and 1.32 +/- 0.21 mm for TFPI-treated arteries; P = .0001 by ANOVA). By quantitative histological analysis, the ratio of neointimal cross-sectional area compared with the area of internal elastic lamina in the DEGR-VIIa-treated group was significantly less than control (0.48 +/- 0.12 versus 0.67 +/- 0.12, P = .0001), and the ratio of neointimal cross-sectional area to the area demarcated by the internal elastic lamina of the TFPI-treated group was significantly reduced compared with the other groups (0.46 +/- 0.20 for TFPI-treated, 0.67 +/- 0.15 for hirudin-treated, 0.61 +/- 0.15 for TAP-treated, and 0.64 +/- 0.13 for control groups; P = .003).

CONCLUSIONS

Treatment with DEGR-VIIa or TFPI for 3 days in this rabbit atherosclerotic injury model reduced angiographic restenosis and decreased neointimal hyperplasia compared with controls. These findings highlight the importance of early initiators of the extrinsic coagulation pathway, especially factor VII and tissue factor, in the response to arterial injury.