Should emicizumab be used in patients with acquired hemophilia A?

Emicizumab is currently approved to prevent bleeding in patients with congenital hemophilia A with or without neutralizing antibodies (inhibitors) against factor VIII (FVIII). Here, we present a case-based discussion of its potential use in acquired hemophilia A (AHA), a severe bleeding disorder caused by autoantibodies against FVIII. State-of-the-art management is based on bypassing agents (recombinant factor VIIa, activated prothrombin complex concentrate) and recombinant porcine FVIII; immunosuppressive therapy (corticosteroids, rituximab, cyclophosphamide) is used to suppress autoantibody formation. Case reports and one series suggest that emicizumab can reduce the risk of bleeding and the requirement for hemostatic therapy until remission of AHA is achieved. Further, it may allow to postpone the start of immunosuppressive therapy or to use less intense regimens. However, the risk-benefit assessment of emicizumab in AHA is difficult because demographic and clinical characteristics are different compared with congenital hemophilia. Prospective clinical trials are needed before the use of emicizumab can be recommended in AHA.

Impact of double heterozygosity for Factor V Leiden and Prothrombin G20210A on the thrombotic phenotype

INTRODUCTION

Because of the rarity of double heterozygosity for Factor V Leiden (FVL) and Prothrombin (FII) G20210A, little is known about the thrombotic phenotype in double heterozygotes.

MATERIAL AND METHODS

In a retrospective cohort study of patients referred for a thrombophilia work-up, we investigated whether double heterozygotes (n = 138) exhibit a more severe thrombotic phenotype compared with single FVL or FIIG20210A heterozygotes, single FVL homozygotes, or wildtype carriers.

RESULTS

The risk of venous thromboembolism (VTE) was higher for female but not male double heterozygotes compared with single heterozygotes (FVL: 2.51, 95%CI 1.55-4.08, FIIG20210A: 1.75, 95%CI 1.14-2.68) and wildtype carriers (HR 2.53, 95%CI 1.58-4.05) but not compared with FVL homozygotes (HR 1.31, 95%CI 0.94-1.83). Female double heterozygotes developed VTE nearly a decade earlier than wildtype carriers and FVL heterozygotes (mean 44.2 vs. 52.6 and 52.2 years), most often in association with oral contraceptives. Spontaneous VTE and arterial thromboembolic events were not more frequent in double heterozygotes compared with the other genotype groups. Deep vein thrombosis (DVT) of the lower limb was the predominant VTE location in double heterozygotes, atypical vein thrombosis was rare. A phenomenon that has been described as the FVL paradox, a higher proportion of isolated DVT than pulmonary embolism, was also found for double heterozygotes.

CONCLUSION

The thrombotic phenotype in double heterozygotes resembles the appearance of the thrombotic phenotype in FVL carriers but the thrombotic risk is aggravated by women-specific risk factors.

Familial Multiple Coagulation Factor Deficiencies (FMCFDs) in a Large Cohort of Patients-A Single-Center Experience in Genetic Diagnosis

Background: Familial multiple coagulation factor deficiencies (FMCFDs) are a group of inherited hemostatic disorders with the simultaneous reduction of plasma activity of at least two coagulation factors. As consequence, the type and severity of symptoms and the management of bleeding/thrombotic episodes vary among patients. The aim of this study was to identify the underlying genetic defect in patients with FMCFDs. Methods: Activity levels were collected from the largest cohort of laboratory-diagnosed FMCFD patients described so far. Genetic analysis was performed using next-generation sequencing. Results: In total, 52 FMCFDs resulted from coincidental co-inheritance of single-factor deficiencies. All coagulation factors (except factor XII (FXII)) were involved in different combinations. Factor VII (FVII) deficiency showed the highest prevalence. The second group summarized 21 patients with FMCFDs due to a single-gene defect resulting in combined FV/FVIII deficiency or vitamin K–dependent coagulation factor deficiency. In the third group, nine patients with a combined deficiency of FVII and FX caused by the partial deletion of chromosome 13 were identified. The majority of patients exhibited bleeding symptoms while thrombotic events were uncommon. Conclusions: FMCFDs are heritable abnormalities of hemostasis with a very low population frequency rendering them orphan diseases. A combination of comprehensive screening of residual activities and molecular genetic analysis could avoid under- and misdiagnosis.

Safety of direct oral anticoagulant exposure during pregnancy: a retrospective cohort study

BACKGROUND

Direct oral anticoagulants (DOACs) have largely replaced vitamin K antagonists in many indications for anticoagulation. Prescribed to millions of patients, including women of reproductive age, exposure to DOACs in early pregnancy is not uncommon, but data on the embryotoxic risks are scarce. We aimed to assess the risk of DOAC embryotoxicity in a large sample of reported cases.

METHODS

In this retrospective cohort study, we collected individual case reports of DOAC exposure in pregnancy from gynaecologists, haematologists, and vascular specialists starting from May, 2015. We obtained exports in April and October, 2017, August, 2018, and December, 2019, from the pharmacovigilance databases of the DOAC manufacturers, the European Medicines Agency (EMA), the German drug authority, and searched the homepage of the US Food and Drug Administration (FDA) for pregnancy exposure reports. Data from the International Society of Thrombosis and Haemostasis (ISTH) registry were obtained in August, 2018, and on July 21, 2020; data from the Teratology Information Service in Ulm, Germany, were received July 22, 2020. We also ran a systematic literature search on July 22, 2020, for cases of DOAC exposure. These data were compiled with those from our 2016 risk assessment and duplicate reports were excluded. Fetal or neonatal abnormalities were classified as a major birth defect according to the European Concerted Action on Congenital Anomalies and Twins (EUROCAT) classification and adjudicated into four categories: relation to DOAC exposure likely, possible, unlikely, or unrelated.

FINDINGS

We identified 1193 reports of DOAC exposure during pregnancy: 49 from physicians, 48 from the ISTH registry, 29 from the Teratology Information Service, 62 from the German drug authority, 536 from Bayer (extracted from the Bayer pharmacovigilance system, the WHO VigiBase, and from the FDA Adverse Event Reporting System), 87 from Boehringer Ingelheim, 16 from Daiichi Sankyo, 98 from the literature search, two from the FDA homepage search, ten from the Risk Evaluation and Mitigation Strategy Review, and 256 from the EMA reports. After excluding potential duplicates, we identified 614 unique cases of DOAC exposure in pregnancy occurring between Feb 1, 2007, and July 9, 2020, that consisted of rivaroxaban in 505 (82%) pregnancies, dabigatran in 36 (6%), apixaban in 50 (8%), and edoxaban in 23 (4%). The median duration of DOAC exposure was 5·3 weeks (IQR 4·0-7·0) into pregnancy. Information on pregnancy outcome was available in 336 (55%) of 614 pregnancies: 188 (56%) livebirths, 74 (22%) miscarriages, and 74 (22%) elective pregnancy terminations. 21 (6%; 95% CI 4-9) of 336 showed fetal abnormalities, of which 12 (4%; 2-6) were adjudicated as major birth defects potentially related to DOAC exposure.

INTERPRETATION

Although reports of pregnancy outcomes after DOAC exposure are missing important details and predominantly describe rivaroxaban exposures, the available data do not suggest that DOAC exposure in pregnancy carries a high risk of embryopathy. The 2016 ISTH guidance against elective pregnancy termination for fear of DOAC embryotoxicity and the recommendation in favour of close pregnancy surveillance is still valid. Pregnancy outcome data are inconsistently captured in pharmacovigilance databases, indicating a strong need for a more robust system of reporting.

FUNDING

None.

[Anticoagulation-direct oral anticoagulants]

Since direct oral anticoagulants (DOAC) have become available, use of anticoagulant treatment has become easier and safer-for patients suffering from thromboembolic diseases as well as for patients with atrial fibrillation: Because of constant bioavailability, fixed dose regimen treatment is possible, monitoring not necessary and severe bleeding complications-particularly intracranial hemorrhages-rare in comparison to vitamin K anticoagulants. To gain all these advantages, it is essential to give DOAC in the correct dosage. Dose reduction of single DOAC has to be considered depending on underlying disease, body weight and renal function. DOAC are not allowed in patients with artificial heart valves, in pregnancy and in children. In case of severe bleeding complications under DOAC treatment, prothrombin complex concentrates is one treatment option. For dabigatran an antidote is available.

Relevance of a single dose of 270 μg/kg recombinant factor VIIa for the treatment of patients with haemophilia and inhibitors

Recombinant activated factor VII (rFVIIa; Novo Seven®) is, besides other indications, authorised for the treatment of bleeding episodes in patients with hereditary haemophilia A or B and inhibitors. Based on the results of three clinical studies, marketing authorisation was granted for the single dose of 270 μg/kg body weight rFVIIa for the treatment of mild-to-moderate bleeding episodes in patients with haemophilia A or B with inhibitors in March 2007. Thereupon, an expert group analysed the relevance of this additional treatment option for clinical routine. Compared with the repeated application of 90 μg/kg body weight rFVIIa, quality of life may be improved if the single dose of 270 μg/kg body weight rFVIIa reduces the number of injections. The single dose has a benefit for those patients who require several rFVIIa applications or who do not respond adequately to low doses. Moreover, patients with poor venous access or who fear injections or reject them (especially children) may benefit from the single dose. The prescription of 270 μg/kg body weight rFVIIa as a single dose instead of multiple dosing of 90 μg/kg body weight is basically an individual and indication-related decision.

Orale Antikoagulanzien vom Cumarintyp

Es wird ein Überblick über Pharmakologie und Indikationen zur Therapie mit Vitamin-K-Antagonisten gegeben sowie zur Therapiehandhabung mit Selbstkontrolle durch die Patienten .

Long- and short-term in vitro D-dimer stability measured with INNOVANCE D-Dimer

In vitro D-dimer stability in plasma is widely assumed, but has not yet been documented by systematic studies using samples covering a wide range of D-dimer. We investigated the short- and long-term stability of D-dimer in clinical citrated plasma samples with normal and pathological levels. The short-term stability was analysed by measuring D-dimer fresh, after storage of plasma for 4 hours at room temperature (RT) and after an additional 24 h storage at +2 to +8°C (n=40). Long-term stability samples (n=40) were measured fresh and after storage for 19, 25 and 36 months at ≤-60°C. The effect of repeated freezing was analysed by measuring samples (n=50) fresh and after four consecutive freeze-thaw cycles. D-dimer was measured on the BCS System using the INNOVANCE D-Dimer assay (Siemens Healthcare Diagnostics Products GmbH, Marburg, Germany). D-dimer values at baseline ranged from 0.23–22.2 mg/l FEU. The mean percentage change after storage for 4 hours at RT and additional 24 hours at +2 to +8°C was +3.8% and +2.7%, respectively. The mean percentage change after frozen storage for 19, 25 and 36 months at ≤-60°C was –11.7%, –4.8% and –9.3%, respectively. The small decrease of D-dimer values after frozen storage was not time-dependent. Repeated freezing did not significantly alter D-dimer values (mean change ≤5%). The data demonstrate stability of D-dimer in plasma prior to freezing for up to 4 hours at RT and for up to 24 hours at +2 to +8°C as well as in plasma stored for up to three years at ≤-60°C.

Increase in the plasma levels of protein Z-dependent protease inhibitor in normal pregnancies but not in non-pregnant patients with unexplained recurrent miscarriage

Protein Z (PZ)-dependent protease inhibitor (ZPI) is a serine protease inhibitor which efficiently inactivates activated factor X, when ZPI is complexed with PZ in plasma. Reduced plasma levels of ZPI and PZ have been reported in association with thrombosis. It has also been reported that PZ increases during pregnancy and that its partial deficiency is related to early pregnancy loss or recurrent miscarriage (RM). However, until now there has been no report on ZPI in pregnancy. To explore the possible role(s) of ZPI in the maintenance of pregnancy, we studied 42 non-pregnant normal women, 32 women with normal pregnancies, and 134 cases of unexplained RM in Japan, as well as 64 non-pregnant normal German females. Plasma ZPI was measured by in-house ELISA. There were significantly higher concentrations of plasma ZPI in normal pregnancies compared to non-pregnant women. The present study also confirmed that both factor X, the major target of ZPI, and protein Z increased during normal pregnancies. This increased ZPI and PZ may counteract the increased activated factor X, which may in turn contribute to the maintenance of normal placental circulation. Plasma ZPI levels were unchanged in non-pregnant RM women, while the plasma PZ level was slightly reduced, a finding consistent with existing reports. The exact relationship between RM and this unaltered ZPI with mild PZ reduction relative to normal pregnancies warrants further investigation.

This work was presented at the 23rd International Society on Thrombosis and Haemostasis meetings in Kyoto, July 2011.

Reduced platelet aggregation in a boy with scurvy

Pediatric scurvy is a rare condition characterized by perifollicular petechiae and bruising, hemorrhagic gingivitis and musculoskeletal symptoms, all assumed to be predominantly related to abnormal collagen structure. We report on a 9-year-old autistic boy with vitamin C deficiency due to a highly limited food range presenting with multiple petechiae, gum bleeding and debilitating bone pain, in whom platelet aggregometry revealed a distinctly reduced thrombocyte aggregation, normalizing after vitamin C supplementation. This observation indicates that platelet dysfunction may additionally contribute to the hemorrhagic diathesis in scurvy, and demonstrates that ascorbic acid deficiency should be considered in children with an otherwise unexplained acquired thrombocytopathy.

Deficiencies of antithrombin, protein C and protein S - practical experience in genetic analysis of a large patient cohort

Deficiencies of natural anticoagulant proteins including antithrombin (AT), protein C (PC) and protein S (PS) are important causes of inherited thrombophilia. This study aimed to report on the practical experience gained in performing genetic analyses of a large cohort of patients with AT, PC and PS deficiencies and to relate this knowledge to clinical application. We genotyped a large cohort of 709 unrelated patients with AT (231), PC (234) and PS (244) deficiencies referred to us by physicians throughout Germany. Mutations were detected by direct sequencing and multiplex ligation-dependent probe amplification (MLPA). The highest mutation detection rate (MDR) was found for the SERPINC1 gene (83.5%), followed by the PROC (69%) and PROS1 (43%) genes. Even at AT activities close to the normal range (75%), the MDR was 70%. Contrastingly, for PC and PS deficiencies, the MDR dropped significantly and mildly lowered to subnormal values. At PS activities >55% for PS no mutations were detected. Mutation profiles of all three genes were similar with the highest prevalence for missense mutations (63-78%), followed by nonsense (7-11%), splice-site mutations (7-13%), small deletions (1-8%), small insertions/duplications (1-4%) and large deletions (3-6%). In conclusion, genetic testing is a useful diagnostic tool for diagnosing thrombophilia. Based on our data, genetic analysis for patients with AT deficiency is indicated for all subnormal activities. In contrast, genotyping is not advisable for PC activities >70% and for PS activities >55%.

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.

Inhibitor-immunology-study. Evaluation of inhibitor development in haemophilia B

The development of inhibitors in haemophilia B is one of the most important complications of replacement therapy, affecting mortality and morbidity. Inhibitor development is based on complex immunological factors, and to date, only little is known about its underlying mechanisms. Here, we present first results of the haemophilia B group of our Inhibitor-Immunology study.

PATIENTS, METHODS

So far we have analysed 15 patients with haemophilia B. Four of them developed a high titre inhibitor; the remaining 11 had no inhibitor. We evaluated 9 SNPs in 8 genes (CD40, CTLA-4 , IL-1β, IL-10, TLR2 , TLR4, TLR9, TNF-α). We compared the distribution of these alleles between inhibitor and non-inhibitor haemophilia B patients and between haemophilia B patients and a normal male control population. HLA typing was performed in all patients. Results, discussion: There appears to be a trend towards a skewed distribution of TLR 9, IL-10 and CTLA4 alleles in haemophilia B patients. Due to the limited number these differences are, however, not statistically significant. The t-test of all patients with inhibitor versus without inhibitor was significant for HLA-A*03 and DPB1*0401 and borderline for DRB1*0201.

[New anticoagulants. Characteristics, monitoring and management of bleeding]

Vitamin K antagonists and heparins have been standard anticoagulation drugs over the past decades. They are effective and safe but they have several drawbacks which has led to the development of new oral anticoagulants. Dabigatran etexilate is a specific oral thrombin inhibitor and rivaroxaban and apixaban are oral inhibitors of factor Xa. These agents produce a predictable anticoagulant response after fixed-dose administration so that routine coagulation monitoring is unnecessary. Currently, dabigatran etexilate, rivaroxaban and apixaban are licensed for thromboprophylaxis after elective total hip or knee replacement surgery. Since august 2011, dabigatran etexilate is licensed for patients with atrial fibrillation, rivaroxaban will follow. However, indications will be expanded e.g. for therapy of venous thromboembolism. It is important to be aware of the pharmacokinetic and pharmacodynamic profiles of these new agents. The drugs considerably influence the global test of coagulation thus making an interpretation of test results difficult. Currently, there is a lack of suitable coagulation tests to monitor anticoagulation in emergency cases, such as bleeding. Specific antidotes are not yet available.

Clinical multicenter evaluation of a new FXa-based Antithrombin assay

INTRODUCTION

The determination of functional Antithrombin is a central part of thrombophilia screening. In this multicenter study, a new FXa-based method (INNOVANCE® Antithrombin) was evaluated on four different analyzers.

METHODS

The INNOVANCE Antithrombin method was evaluated by precision and reference interval studies and by comparing the new method with established methods through parallel measurement of samples from 249 patients and 151 apparently healthy individuals.

RESULTS

The INNOVANCE Antithrombin assay demonstrated on all analyzers repeatability coefficients of variation (CVs) ≤ 3.2% and within-device and between-run CVs ≤ 6.9%. The reference intervals of all analyzers are comparable with 2.5th percentiles between 80% and 85% of normal. The INNOVANCE Antithrombin and the FIIa-based Berichrom® AT III (A) methods demonstrated good concordance with correlation coefficients of r = 0.908 or higher. The INNOVANCE Antithrombin method demonstrated furthermore an excellent comparability with the STA® Antithrombin III assay and an acceptable comparability with the Coamatic® LR Antithrombin assay. The patients with congenital deficiency (n = 31) were identified with all assays except for the patients carrying the P41L heparin-binding site mutation, which was only identified with the INNOVANCE Antithrombin and the STA Antithrombin III methods.

CONCLUSION

The INNOVANCE Antithrombin assay has high sensitivity for Antithrombin deficiencies and is reliable, precise and suitable for routine clinical use.

Inhibitor-Immunology-Study

The development of inhibitors in haemophilia B is one of the most important complications of replacement therapy, affecting mortality and morbidity. Inhibitor development is based on complex immunological factors, and to date, only little is known about its underlying mechanisms. Here, we present first results of the haemophilia B group of our Inhibitor-Immunology study.

Patients, methods So far we have analysed 15 patients with haemophilia B. Four of them developed a high titre inhibitor; the remaining 11 had no inhibitor. We evaluated 9 SNPs in 8 genes (CD40, CTLA-4, IL-1β, IL-10, TLR2, TLR4, TLR9, TNF-α). We compared the distribution of these alleles between inhibitor and non-inhibitor haemophilia B patients and between haemophilia B patients and a normal male control population. HLA typing was performed in all patients.

Results, discussion There appears to be a trend towards a skewed distribution of TLR 9, IL-10 and CTLA4 alleles in haemophilia B patients. Due to the limited number these differences are, however, not statistically significant.The t-test of all patients with inhibitor versus without inhibitor was significant for HLA-A*03 and DPB1*0401 and borderline for DRB1*0201.

Distinct C-terminus of the B subunit of factor XIII in a population-associated major phenotype: the first case of complete allele-specific alternative splicing products in the coagulation and fibrinolytic systems

OBJECTIVES

The purpose of this study was to elucidate the molecular bases of the heterogeneity of the B subunit of coagulation factor XIII (FXIII-B), classified by isoelectric focusing into its three population-associated major phenotypes.

METHODS AND RESULTS

By genetic sequencing and polymerase chain reaction (PCR)-restriction fragment length polymorphism analyses, a C-to-G change was identified in intron K for the Asian-associated major phenotype FXIII-B*3. A transcript containing the novel exon XII' was detected by reverse transcription PCR using hepatocyte cell lines with this allele. The exclusive existence of a novel C-terminal peptide in a homozygote of FXIII-B*3 was also detected by matrix-assisted laser-desorption ionization time of flight mass spectrometry. The FXIII-B*3 isoform had a C-terminus 15 residues longer than the other isoforms, containing two additional basic amino acids and one extra acidic amino acid. Accordingly, the C-to-G nucleotide substitution created an efficient splice acceptor AG dinucleotide, which resulted in allele-specific alternative splicing in intron K. When compared with FXIII-B*1, the third major phenotype, FXIII-B*2, had an A-to-G change in exon III, converting His95 to Arg, and a rare phenotype, FXIII-B*4, had an A-to-T change in exon VII, converting Glu368 to Val.

CONCLUSIONS

We found an extremely rare event of complete allele-specific alternative splicing for FXIII-B. The FXIII-B*3 isoform had a distinct C-terminal peptide, while the FXIII-B*2 and FXIII-B*4 isoforms had His95 to Arg and Glu368 to Val substitutions, respectively, which led to differential isoelectric points of these isoforms. Such variations in the amino acid sequence of FXIII-B may have profound effects on its structure-function relationship, plasma FXIII levels, and disease susceptibility.

[Relevance of a single dose of 270 microg/kg recombinant factor VIIa for the treatment of patients with haemophilia and inhibitors - Recommendations from the GTH experts]

Recombinant factor VIIa (rFVIIa; NovoSeven) is, besides other indications, authorised for the treatment of bleeding episodes in patients with hereditary haemophilia A or B and inhibitors. Based on the results of three clinical studies, marketing authorisation was granted for the single dose of 270 microg/kg body weight rFVIIa for the treatment of mild to moderate bleeding episodes in patients with haemophilia A or B with inhibitors in March 2007. Thereupon, an expert group analysed the relevance of this additional treatment option for clinical routine. Compared with the repeated application of 90 microg/kg body weight rFVIIa, quality of life may be improved if the single dose of 270 microg/kg body weight rFVIIa reduces the number of injections. The single dose has a benefit for those patients who require several rFVIIa applications or who do not respond adequately to low doses. Moreover, patients with poor venous access or patients who fear injections or reject them (especially children) may benefit from the single dose. The prescription of 270 microg/kg body weight rFVIIa as a single dose instead of multiple dosing of 90 microg/kg body weight is basically an individual and indication-related decision.

[Anticoagulation by oral treatment with vitamin K antagonists]

A survey is given on pharmacology and indications for the treatment with vitamin K antagonists. The therapeutic handling and self control by the patient is described.

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.

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.

Elevated Lipoprotein(a) does not promote early atherosclerotic changes of the carotid arteries in young, healthy adults

BACKGROUND

Elevated levels of Lipoprotein(a) [Lp(a)] have been linked to an increased risk of ischemic cardiovascular events. Yet the mechanism by which Lp(a) might contribute to this increased risk is not clear.

METHODS

To elucidate whether high plasma levels of Lp(a) contribute to the development of early atherosclerotic vessel wall changes, the intima-media thickness of the common carotid arteries [CCA-IMT] of 151 healthy young volunteers without additional relevant cardiovascular risk factors was measured by high-resolution ultrasound. Plasma concentrations of Lp(a) were quantified and other established risk factors, such as body mass index [BMI], plasma levels of cholesterol, triglycerides and homocysteine, were determined. Furthermore, the carotid arteries were examined for the presence of plaques and stenoses.

RESULTS

Univariate analysis showed a significantly negative correlation of CCA-IMT with HDL cholesterol and positive correlations with age, BMI, total and LDL cholesterol, triglycerides and even with homocysteine, but not with Lp(a). When the study population was dichotomized according to Lp(a) levels, no statistically significant differences in CCA-IMT could be detected between persons with plasma Lp(a)<300mg/l or >or=300mg/l, respectively.

CONCLUSION

Our data suggest that elevated Lp(a) levels alone do not contribute to increased cardiovascular risk by promoting early atherogenesis in vivo.

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.

Value of soluble adhesion molecules and plasma coagulation markers in assessing transplant coronary artery disease in pediatric heart transplant recipients

BACKGROUND

With an increasing number of heart transplantations (HTx) performed in children and an extended long-term survival of these patients, the importance of transplant coronary artery disease (TCAD) rises in this group of transplant recipients. Reliable serum markers for diagnosis or non-invasive monitoring of this disease in pediatric transplant recipients are still missing. We studied the systemic expression of adhesion molecules as well as plasma coagulation markers and the occurrence of TCAD and/or rejection in pediatric heart transplant recipients.

METHODS AND RESULTS

The systemic plasma levels of soluble forms of sVCAM-1 and sICAM-1, d-dimer, tissue factor (TF), prothombin fragments F(1+2), and tissue factor pathway inhibitor (TFPI) were assessed in serial venous blood samples (2-4 per patient) in 50 pediatric transplant recipients children and 63 age- and sex-matched non-transplanted controls. TCAD and rejection were diagnosed angiographically or by combined histological, echocardiographic, or clinical signs, respectively. Plasma levels of sICAM-1 and sVCAM-1, d-dimers and prothrombin fragment F(1+2) but not TF and TFPI were significantly increased in children following HTx compared with non-transplanted controls (p<0.001). Among the transplanted patients, sICAM-1 levels were significantly higher in patients with angiographically detectable TCAD than in patients without evidence of TCAD (p<0.005). Plasma sICAM-1 levels above a cutoff value of 1500 ng/mL (95.5 percentile of control values) were indicative of the presence of TCAD (odds ratio 2.7; 95% confidence interval, 1.34-5.56, p = 0.022; Fisher's exact test). Only d-dimers were found to be significantly elevated in children with signs of myocardial rejection compared with those without rejection.

CONCLUSIONS

Our results suggest that plasma sICAM-1 and d-dimer levels may be potentially useful to non-invasively assess TCAD and rejection, respectively, in pediatric heart transplant recipients.

Argatroban treatment for patients with intolerance to heparin and hirudin

Argatroban is a synthetic thrombin inhibitor that acts independently of any cofactor. It inhibits free as well as fibrin- and clot-bound thrombin. The clinical history of two patients is presented, both with previous allergic reactions toward heparin and hirudin. In both patients, antibodies against hirudin were documented. Argatroban was successfully used in both patients without any side effects. We conclude argatroban to be the drug of choice in patients with intolerance to heparin and hirudin. Moreover, genetic variations affecting the hepatic catabolism of argatroban might exist, because very different dosages of argatroban were needed in the two patients.

R255h Amino acid substitution of protein Z identified in patients with factor V Leiden mutation

The clinical significance of diminished protein Z in plasma is controversial. Studies in mice demonstrated that deficiency of protein Z dramatically increases the prothrombotic tendency of factor V Leiden mutation. This finding was confirmed by initial results in humans, indicating that thromboembolism in factor V Leiden patients with lowered protein Z level occurs earlier than in patients with normal protein Z levels. Consequently, the aim of our present study was to find out whether genetic alterations of protein Z were demonstrated in patients with factor V Leiden mutation and early onset of thromboembolic disease. DNA-sequencing of the protein Z gene was performed in two patients with factor V Leiden mutation, early onset of thromboembolism, and lowered protein Z levels. In both patients, R255H substitution of the protein Z gene was identified. Subsequently, the R255H substitution was also found in 12 of 132 additional patients. Patients presenting with the R255H substitution in addition to factor V Leiden mutation showed thromboembolic events more frequently than factor V Leiden patients without R255H substitution of the protein Z gene. In conclusion, R255H substitution of the protein Z gene seems to influence clinical symptoms of thromboembolism in factor V Leiden patients.

A naturally occurring E30Q mutation in the Gla domain of protein Z causes its impaired secretion and subsequent deficiency

Protein Z is a vitamin K-dependent glycoprotein that plays a role in the regulation of coagulation. A nucleotide substitution of G by C in exon II of the protein Z gene, resulting in the replacement of Glu-30 with Gln (E30Q), and a G to A transition at the 79th nucleotide in intron F (IntF79G/A) were heterozygously identified in a patient with a severe thrombotic tendency, whose plasma protein Z level was about 15% of normal. Other vitamin K-dependent coagulation factors were within normal ranges. Glu-30 is one of 13 gamma-carboxylation sites in protein Z and is well conserved among vitamin K-dependent proteins. Expression studies revealed that the E30Q mutant was not released from synthesizing cells, although wild-type protein Z was readily secreted in a vitamin K-dependent fashion. The E30Q mutant was N-glycosylated, gamma-carboxylated, and translocated from the endoplasmic reticulum (ER) to the Golgi in the presence of vitamin K, as was the wild type. Coexpression of E30Q with wild-type protein Z interfered with the secretion of the wild type, while only a minor or no effect was observed on the secretion of factor X and plasminogen. The IntF79A allele has been reported to be also associated with lowered protein Z levels.

Osteoporose bei Patienten unter oraler Antikoagulantien-Therapie

BACKGROUND AND OBJECTIVE

Osteoporosis is thought to be one possible side-effect of oral anticoagulant therapy, especially after long-term treatment. Nevertheless, data concerning this problem only exist from earlier years. Therefore, we decided to look for the incidence of osteoporosis in patients under long-term oral anticoagulant treatment.

PATIENTS AND METHODS

30 patients (15 female, 15 male) - age between 38 and 77 years (average age 65,1+/-11,2 years) were examined. Group A: 10 patients with a capture time between 0,5 - 5 years, Group B: 10 patients with a capture time between 6 - 11 years, Group C: 10 patients with a capture time more than 11 years. The control group consisted 30 healthy persons - age between 39 and 81 years (18 female, 12 male, average age 61,5 +/- 12 years).

RESULTS

In 21 out of 30 patients (9 female, 12 male) osteoporosis was found due to results of x-ray and bone-density-measurements. In 9 patients (6 female, 3 male) no osteoporosis was detected. No correlation between appearance of osteoporosis and duration of oral anticoagulant treatment was detected. Nevertheless, the number of patients presenting with osteoporosis in comparison with the control group was highly unexpected and astonishing.

CONCLUSION

While treating patients with oral anticoagulants the possibility of appearing osteoporosis should be kept in view. In those circumstances the therapy should be supported by calcium and vitamin D.

[Oral anticoagulants and coumarin classes]

A survey is given on pharmacology and indications for the treatment with vitamin K antagonists. The therapeutic handling and self control by the patient is described.

Orale Antikoagulanzien vom Cumarintyp

Es wird ein Überblick über Pharmakologie und Indikationen zur Therapie mit Vitamin-K-Antagonisten gegeben sowie zur Therapiehandhabung mit Selbstkontrolle durch die Patienten.

Arthritis is linked to local and systemic activation of coagulation and fibrinolysis pathways

BACKGROUND

Activation of coagulation and fibrinolysis play a role in the pathophysiology of experimental arthritis.

OBJECTIVE

To determine the extent of activation of the coagulation and fibrinolytic pathways in different joint diseases in humans and to ascertain the factors that may influence fibrin deposition within the joint.

METHODS

Plasma from normal subjects (controls, n= 21) and plasma and synovial fluid samples from patients with rheumatoid arthritis (RA; n = 64), osteoarthritis (OA; n = 29), spondyloarthropathy (SpA; n = 22) and crystal arthritis (CA; n = 25) were analyzed for the levels of TF (tissue factor) and tissue factor pathway inhibitor (TFPI) activities, thrombin-antithrombin III (TAT) complexes, and F1 + 2 (thrombin fragment), fibrin d-dimer and thrombin-activated fibrinolysis inhibitor (TAFI) antigenic levels. The measurements were analyzed by pairwise correlation with each other as well as with standard parameters of inflammation [C-reactive protein (CRP), joint leukocyte count]. Inter-group comparisons were performed to look for disease-specific differences.

RESULTS

Compared with healthy controls, patients with joint diseases had higher levels of TAT, F1 + 2 and d-dimers in their plasma. In the synovial fluid, TF activity, TAT, d-dimers, and TAFI were significantly higher in inflammatory arthritides than in OA. The levels were highest in RA patients. In the plasma, TF activity was correlated with TAT and d-dimer levels with CRP, TFPI, and TAT. In the synovial fluid, TF activity correlated with plasma CRP levels, synovial fluid leukocyte count, and synovial TAT and TAFI levels. In addition, synovial d-dimers correlated with CRP, and synovial TAFI levels were correlated with synovial F1 + 2 and TAT.

CONCLUSIONS

Activation of the coagulation and fibrinolytic cascades in the joint and in the circulation is evident in both inflammatory and degenerative joint diseases. Within the joint, inflammatory mechanisms leading to TF-mediated activation of the coagulation pathway and subsequent fibrin deposition is the most likely explanation for the observed findings. In the plasma, the link between inflammation (CRP increase) and TF activation is weak, and a non-TF-mediated mechanism of coagulation activation could explain these findings. RA is characterized by significantly higher levels of TAT in the synovial fluid and plasma than other arthritides. Although fibrinolytic activity is linked to inflammation, the increased amounts of TAFI in the joint, particularly in RA, may explain why fibrin formation is so prominent in this condition compared with other joint diseases.

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.

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.