Bettina Kemkes-Matthes

Low-Molecular-Weight Heparin Versus Placebo for the Prevention of Venous Thromboembolism in Metastatic Breast Cancer or Stage III/IV Lung Cancer

In 2 double-blind studies, ambulatory patients with objectively proven, disseminated metastatic breast carcinoma (TOPIC-1) or stage III/IV non–small-cell lung carcinoma (TOPIC-2) were randomized to certoparin 3000 IU or placebo subcutaneously once daily, for 6 months. Primary efficacy outcome was objectively confirmed symptomatic or asymptomatic venous thromboembolism (VTE). Safety outcomes included bleeding (major and minor), and thrombocytopenia. TOPIC-1 was halted after an interim analysis. Venous thromboembolism occurrence was not different between treatment groups in TOPIC-1 (4% treated with certoparin, 7 of 174 vs 4% receiving placebo, 7 of 177, odds ratio [OR] 1.02; 95% confidence interval [CI] 0.30-3.48) and in TOPIC-2 (4.5%, 12 of 268) vs 8.3%, 22 of 264, respectively, OR 0.52; CI 0.23-1.12). Mortality was not different between groups. A post hoc analysis showed certoparin significantly reduced VTE in stage IV lung carcinoma (3.5% vs 10.2%; P = .032) without increased bleeding. In conclusion, thrombosis risk and prophylactic benefit was highest in stage IV lung carcinoma patients.

Risk stratification and heparin prophylaxis to prevent venous thromboembolism in pregnant women.

Women with a history of venous thromboembolism (VTE), thrombophilia or both may be at increased risk of thrombosis during pregnancy, but the optimal management strategy is not well defined in clinical guidelines because of limited trial data. A strategy of risk assessment and heparin prophylaxis was evaluated in pregnant women at increased risk of VTE. In a prospective trial (Efficacy of Thromboprophylaxis as an Intervention during. Gravidity [EThIG]), 810 pregnant women were assigned to one of three management strategies according to pre-defined risk factors related to history of VTE and thrombophilic profile. Low-risk women (group I), received 50-100 IU dalteparin/kg body weight/day for 14 days postpartum, or earlier when additional risk factors occurred. Women at high (group II) or very high risk (group III) received dalteparin from enrollment until six weeks postpartum (50-100 IU and 100-200 IU/kg/day, respectively). Objectively confirmed, symptomatic VTE occurred in 5/810 women (0.6%; 95% confidence interval [CI], 0.2 to 1.5%) (group I, 0 of 225; II, 3/469; III, 2/116). The rate of serious bleeding was 3.0% (95 % CI, 1.9 to 4.4%); 1.1% (95 % CI, 0.5 to 2.2%) was possibly dalteparin-related. There was no evidence of heparin-induced thrombocytopenia, one case of osteoporosis, and rates of miscarriage and stillbirth were similar to previous, retrospective studies. Risk-stratified heparin prophylaxis was associated with a low incidence of symptomaticVTE and few clinically important adverse events. Antepartum heparin prophylaxis is, therefore, warranted in pregnant women with idiopathic thrombosis or symptomatic thrombophilia.

Markers of platelet activation and platelet-leukocyte interaction in patients with myeloproliferative syndromes.

INTRODUCTION Changes in platelet count and function contribute to thrombo-hemorrhagic episodes in chronic myeloproliferative syndromes (MPS). We used flow cytometry to study platelet-leukocyte conjugates and markers of platelet activation in patients with MPS. METHODS Whole blood from patients with chronic myelogenous leukemia (CML), polycythemia vera (PV), chronic myelofibrosis (MF), and essential thrombocythemia (ET) and from healthy volunteers was prepared for flow cytometry. Platelet microparticles and platelet microaggregates were identified with anti-CD42b and forward scatter, activated platelets with anti-CD62p. Anti-CD42b, anti-CD14, and anti-CD45 were used to study platelet-leukocyte conjugates. RESULTS The percentage of CD62p-positive platelets was elevated in all myeloproliferate syndrome subtypes. The median percentage of platelet microparticles was 5.2% in controls and significantly higher in PV (12.0%), MF (11.0%), and ET (11.0%, all p<0.05). There was an increased percentage of platelet-neutrophil conjugates in patients with PV (8.3%) and ET (10.4%) compared to normal controls (6.8%, all p<0.05). Platelet-monocyte conjugates were 8.0% in controls and elevated in PV (15.4%) and ET (15.0%, all p<0.05). Patients with a history of venous or arterial thrombotic events had slightly less platelet-leukocyte conjugates and slightly more microparticles than patients without thrombosis; however, this difference was not statistically significant. CONCLUSIONS These findings suggest that platelet-leukocyte conjugate formation occurs in myeloproliferative syndromes and indicates platelet activation. Also, platelet microparticles are elevated and might provide a catalytic surface for thrombin generation. This could explain the clinical observation that patients with myeloproliferative syndromes have an increased risk to experience arterial or venous thrombotic events.

The G534E polymorphism of the gene encoding the factor VII–activating protease is associated with cardiovascular risk due to increased neointima formation

The G534E polymorphism (Marburg I [MI]) of factor VII–activating protease (FSAP) is associated with carotid stenosis and cardiovascular disease. We have previously demonstrated that FSAP is present in atherosclerotic plaques and it is a potent inhibitor of vascular smooth muscle proliferation and migration in vitro. The effect of wild-type (WT)- and MI-FSAP on neointima formation in the mouse femoral artery after wire-induced injury was investigated. Local application of WT-FSAP led to a 70% reduction in the neointima formation, and this effect was dependent on the protease activity of FSAP. MI-FSAP did not inhibit neointima formation in vivo. This is due to a reduced proteolytic activity of MI-FSAP, compared to WT-FSAP, toward platelet-derived growth factor BB, a key mediator of neointima development. The inability of MI-FSAP to inhibit vascular smooth muscle accumulation explains the observed linkage between the MI-polymorphism and increased cardiovascular risk. Hence, FSAP has a protective function in the vasculature, and analysis of MI polymorphism is likely to be clinically relevant in restenosis.

Protein Z influences the prothrombotic phenotype in Factor V Leiden patients

Protein Z enhances the inhibition of factor Xa by protein Z-dependent protease inhibitor (ZPI). Thus, diminution of protein Z should induce prothrombotic tendency due to lowered cofactor activity for ZPI. In Factor V Leiden mice, prothrombotic tendency of severe diminution or lack of protein Z was demonstrated. We here present first studies in humans, indicating that diminution of protein Z in factor V Leiden patients aggravates thromboembolic risk.

Factor VII-activating protease (FSAP): Vascular functions and role in atherosclerosis

FSAP is a plasma serine protease for which a potential role in the regulation of coagulation and fibrinolysis is postulated, based on its property to activate factor VII (FVII) as well as pro-urokinase (uPA). In clinical studies, the G534E single nucleotide polymorphism (Marburg I) of FSAP has been linked to late complications of atherothrombosis and is associated with a low proteolytic activity, particularly, towards pro-uPA. This has stimulated much interest in a search for additional functions of FSAP in the cardiovascular system. FSAP is a potent inhibitor of vascular smooth muscle cell proliferation and migration in vitro and local application of FSAP (but not Marburg I variant) in animal models reduces neointima formation. This is due to a reduced proteolytic activity of the variant isoform towards platelet derived growth factor-BB, a key mediator of neointima development. Moreover, appreciable quantities of FSAP are localized to unstable atherosclerotic plaques and may contribute to plaque instability. These data indicate that the cellular regulatory effects of FSAP may be more important than its influence on haemostasis. In this review the contribution of FSAP to vascular fibroproliferative inflammatory diseases in the context of pericellular proteolysis of the extracellular matrix, growth factor activity and haemostasis will be highlighted.

Screening for thrombophilic risk factors among 25 German patients with cerebral venous thrombosis.

Objectives– In this study the frequency of inherited thrombophilic risk factors in a population of German CVT patients and their influence on clinical outcome were evaluated. Material and methods– Twenty‐five patients (age 37.1±16.3 years) with CVT were screened for inherited coagulation disorders. All participants received a full clinical follow‐up (mean follow‐up period 4.8±6.4 years). Results– Inherited thrombophilic risk factors were identified in 9 (36%) of the 25 patients studied. Four were found positive for the heterozygous factor V Leiden mutation, 2 were heterozygous carriers of the prothrombin‐G20210A‐polymorphism. APC resistance proved to be a reliable screening method for factor V Leiden mutation, whereas genetic evaluation for protein S and C deficiencies failed to demonstrate any mutations despite the identification of 1 patient with a protein C and protein S deficiency each. One patient suffered from a familial plasminogen deficiency. These 9 patients had a less favorable outcome (P<0.05). Conclusion– Our results demonstrate that screening for inherited thrombophilia should be an integral part in the diagnostic work up of CVT patients. Patients with inherited coagulopathies tended to have a less favorable outcome, corroborating recommendations for a longer period of oralanticoagulation.

Fixed-dose, body weight-independent subcutaneous low molecular weight heparin Certoparin compared with adjusted-dose intravenous unfractionated heparin in patients with proximal deep venous thrombosis

Subcutaneous body weight-adjusted low molecular weight heparin (LMWH) has been proven as effective and safe as intravenous aPTT-adjusted unfractionated heparin (UFH) for the treatment of patients with acute deep venous thrombosis (DVT). In this study we evaluate the efficacy of the initial treatment of proximal DVT with a fixed-dose, body weight-independent application of the LMWH Certoparin with a six month follow-up. In a prospective, multicentre, randomized, active-controlled study 1220 patients with objectively diagnosed proximal DVT were randomly assigned to subcutaneous 8000 U anti-factor Xa of Certoparin twice daily for 10 to 14 days or intravenous aPTT-adjusted UFH for 5 to 8 days. Both regimen were followed by oral anticoagulation for 6 months. The primary end point was the rate of symptomatic and objectively confirmed thromboembolic events within 6 months. The aim of the study was to demonstrate the non-inferiority of the Certoparin regimen as compared to UFH. The per-protocol analysis revealed 22 (3.8%) thromboembolic events in the Certoparin group and 24 (4.3%) in patients assigned to UFH within 6 months, thereby proving the non-inferiority (p<0.01), confirmed by intent-to-treat analysis (p<0.001). Major bleeding occurred in 6 and 7 patients started on Certoparin or UFH during the treatment period. Thromboembolic events were equally distributed in body weight categories with < 50, 50-80 and >80 kg as followed: 0, 3.6% and 4.1% of patients for the Certoparin group and 0, 4.6% and 4.2% of patients for the UFH group. The same was true for major bleeding complications with 0, 2.9% and 1.5% for Certoparin and 0, 3.5% and 4.2% for UFH. Overall mortality was 1.9% in the Certoparin group and 2.7% in the UFH group. Fixed-dose body weight-independent subcutaneous LMWH Certoparin is at least as efficacious and safe as intravenous aPTT-adjusted UFH for the initial treatment of acute proximal DVT. This effect is maintained during a 6-months follow-up of treatment with oral anticoagulation.

S protein/vitronectin in chronic liver diseases: correlations with serum cholinesterase, coagulation factor X and complement component C3.

S protein/vitronectin plays an important role as a regulatory component in the terminal steps of the complement‐ and coagulation cascades. In patients suffering from chronic liver diseases, plasma S protein concentration was measured and compared with changes in serum cholinesterase activity, coagulation factor X activity and complement component C3 concentration. Significant decreases of all these proteins were seen in liver cirrhosis. Changes in S protein concentration correlated closely with those of cholinesterase, factor X and complement C3. The data give support for the liver as the main organ of plasma S protein/vitronectin synthesis.

Comparison of β-Thromboglobulin, Flow Cytometry, and Platelet Aggregometry to Study Platelet Activation

This study compares granule membrane protein (GMP)-140 expression measured by flow cytometry, release of beta-thromboglobulin (beta-TG), and platelet aggregometry as markers of platelet activation in vitro. Whole blood was activated with different concentrations of thrombin. There was a significant increase in beta-TG plasma levels after stimulation with 0.01 and 0.04 U thrombin/ml. There was also an increase in GMP-140 expression, but interindividual variability was high. Aggregometry of platelet-rich plasma did not detect platelet activation and formation of platelet aggregates with 0.05 and 0.1 U thrombin/ml, while flow cytometry showed an early and significant increase of GMP-140 expression with these doses. Beta-TG release is a more sensitive marker of platelet activation than GMP-140 while flow cytometry is easier to perform and less susceptible to artifacts.