http://repub.eur.nl/res/aut/11339/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/39556/ 2013-03-01T00:00:00Z Background and aims: It remains unclear when anticoagulant therapy should be given in patients with non-cirrhotic portal vein thrombosis (PVT). The aim of this study was to assess the effect of anticoagulation on recurrent thrombotic events and gastrointestinal bleeding in non-cirrhotic PVT patients. Methods: Retrospective study of all patients with non-cirrhotic PVT (n = 120), seen at our hospital from 1985 to 2009. Data were collected by systematic chart review. Results: Sixty-six of the 120 patients were treated with anticoagulants. Twenty-two recurrent thrombotic events occurred in 19 patients. The overall thrombotic risk at 1, 5 and 10 years was 4%, 8% and 27%, respectively. Seventy-four percent of all recurrent thrombotic events occurred in patients with a prothrombotic disorder. Anticoagulant therapy tended to lower the risk of recurrent thrombosis (hazard ratio [HR] 0.2, P = 0.1), yet the only significant predictor of recurrent thrombotic events was the presence of a prothrombotic disorder (HR 3.1, P = 0.03). In 37 patients, 83 gastrointestinal bleeding events occurred. The re-bleeding risk at 1, 5 and 10 years was 19%, 46% and 49%, respectively. Anticoagulation therapy (HR 2.0, P ≤ 0.01) was a significant predictor of (re)bleeding. Anticoagulation therapy had no effect on the severity of gastrointestinal bleeding. Poor survival was associated with recurrent thrombotic events (HR 3.1 P = 0.02), whereas bleeding (HR 1.6 P = 0.2) and anticoagulant treatment (HR 0.5 P = 0.2) had no significant effect on survival. Conclusions: In non-cirrhotic PVT patients recurrent thrombotic events are mainly observed in patients with underlying prothrombotic disorders. Anticoagulation therapy tends to prevent recurrent thrombosis but also significantly increases the risk of gastrointestinal bleeding. http://repub.eur.nl/res/pub/39565/ 2013-03-01T00:00:00Z http://repub.eur.nl/res/pub/38833/ 2012-11-01T00:00:00Z von Willebrand disease (VWD) affects approximately 1% of the population. Joint bleeds are not a predominant symptom of VWD, however they do occur. Especially in patients with severe VWD, joint bleeds have been described in up to 45% of the patients. Recurrent hemarthroses can lead to joint destruction which is the main cause of morbidity, as is observed in hemophilia patients. In VWD however, the occurrence, severity, onset, treatment and impact of arthropathy have not been well described. This literature review summarizes all publications on arthropathy in patients with hereditary VWD, published until 1-5-2012. Joint bleeds in VWD are associated with low FVIII levels and seem to occur at young age. Depending on the severity of VWD, arthropathy occurs in 2-30% of the patients. Radiological joint damage can be seen but has not systematically been studied. Arthropathy can affect daily functioning and interfere with the quality of life. For acute management of joint bleeds FVIII/VWF concentrates can be used in VWD patients unresponsive to desmopressin or desmopressin in responsive VWD patients. When severe joint bleeds have caused synovitis and arthropathy, chemical or radioactive synovectomy and surgical joint procedures seem feasible to prevent further joint damage. Additional research is needed to learn more about the severity, onset and impact of arthropathy in VWD. Ongoing studies will hopefully answer the question whether prophylactic treatment with coagulation factor concentrates should be considered standard of care in severe VWD to prevent arthropathy. http://repub.eur.nl/res/pub/37999/ 2012-03-01T00:00:00Z http://repub.eur.nl/res/pub/33818/ 2011-11-01T00:00:00Z A nation-wide cross-sectional study was initiated to assess gynaecological and obstetrical symptoms in an unselected cohort of women with moderate and severe von Willebrand disease (VWD) in the Netherlands. A total of 423 women aged ≥16 years were included. Bleeding severity was measured using the Tosetto Bleeding Score (BS). Menorrhagia, defined as occurrence of ≥2 menorrhagia symptoms, was reported by 81%. Of all VWD women, 78% received any kind of treatment for menorrhagia and 20% underwent a hysterectomy predominantly because of severe menstrual bleeding. Over half of the women reported more blood loss than can be expected with a normal delivery. In 52% of reported pregnancy losses curettage was needed because of bleeding. Mean number of live births was 1.9, which is comparable with the general Dutch population. In conclusion, women with moderate or severe VWD frequently have menorrhagia in need of treatment, and 20% of the VWD women underwent a hysterectomy. Bleeding complications occurred in over 50% of the women after childbirth or pregnancy loss. Progeny seems not to be affected in women with moderate or severe VWD. http://repub.eur.nl/res/pub/34432/ 2011-11-01T00:00:00Z Background:Myeloproliferative neoplasms (MPNs) are frequently identified as an underlying cause in patients with non-cirrhotic portal vein thrombosis (PVT). The aim of this study was to describe the long-term outcome of patients with PVT and MPN. Methods:A cohort study was performed including all adult patients referred to our hospital between 1980 and 2008 with non-cirrhotic, non-malignant PVT and confirmed MPN. Results:A total of 44 patients (70% female) were included, with a median age at PVT-diagnosis of 48years (range 18-79). In 31 patients (70%) PVT was the first manifestation of an MPN. Additional risk factors for thrombosis were present in 20 patients (45%). Median follow-up was 5.8years (range 0.4-21). Twenty-three patients (52%) were treated with oral anticoagulants after diagnosis of PVT, of whom 15 (34%) received long-term therapy. During follow-up, 17 patients (39%) experienced at least one episode of gastrointestinal bleeding. Additional thrombotic events occurred in 12 patients (27%). Twelve patients (27%) had progression of the underlying MPN. Seventeen patients (39%) died at a median age of 64years (range 30-88). Death was directly related to end-stage MPN in eight patients (47%) and to a new thrombotic event in three patients (18%). No patients died from gastrointestinal bleeding. Conclusions:PVT is often the presenting symptom of an underlying MPN, highlighting the need for thorough screening for this disease. Recurrent thrombosis is a common and severe complication in patients with PVT and MPN. Mortality is primarily related to the underlying MPN and not to complications of portal hypertension. http://repub.eur.nl/res/pub/30717/ 2011-10-06T00:00:00Z Patients with von Willebrand disease (VWD), the most common inherited bleeding disorder, display large variation in bleeding tendency, which is not completely related to VWF levels. The cause of variability in clinical expression is largely unknown. The effect of plasma fibrinolytic capacity on bleeding tendency in VWD patients has not been investigated. We hypothesized that enhanced fibrinolysis may result in a more severe bleeding phenotype. Therefore, we measured the fibrinolytic potential in patients with moderate or severe VWD to investigate the contribution of fibrinolysis to the bleeding tendency. Fibrinolytic potential was measured as plasma clot lysis time (CLT) with and without addition of potato carboxypeptidase inhibitor (PCI) in 638 patients with moderate or severe VWD who participated in a nationwide multicentre cross-sectional study. Bleeding severity was measured using the Bleeding Score (BS).The CLTs were significantly longer, indicative of hypofibrinolysis, in men compared to women with VWD [106.2 (IQR 95.7-118.1) vs. 101.9 (IQR 92.8-114.0) min]. The CLTs prolonged with increasing age. No association was found between VWF or FVIII levels and CLT, or between VWF or FVIII levels and CLT+PCI. No association was observed for BS in a model with 10log-transformed CLT, adjusted for age, gender, VWF:Act and FVIII [b=6.5 (95%CI -0.3 to 13.4)]. Our study showed that the plasma fibrinolytic potential does not influence bleeding tendency in VWD patients and therefore does not explain the variability in bleeding phenotype in VWD. http://repub.eur.nl/res/pub/30978/ 2011-09-13T00:00:00Z Background: The fibrinogen γ' variant (γ') has both antithrombotic and prothrombotic properties when compared to normal fibrinogen. It may therefore be of relevance in intracerebral hemorrhage and intraventricular extension of the bleeding. Objective: To study the role of γ' in intracerebral hemorrhage, and in intraventricular extension of the hemorrhage. Patients/Methods: We performed a case-control study in 156 controls and 55 patients with intracerebral hemorrhage, with and without intraventricular extension. Levels of fibrinogen γ' and the γ'/total fibrinogen ratio were measured in all participants. Results: Levels of γ' were increased in patients with intracerebral hemorrhage when compared with controls (0.40 vs 0.32 g/l, p < 0.001). The γ'/total fibrinogen ratio was similar in patients and controls (0.092 vs 0.096 p = 0.42). There was evidence for an unfavorable outcome in patients with fibrinogen levels in the highest tertile compared with the lowest tertile (OR 4.0, 95%CI 1.1-15.2), and a nonsignificant trend toward unfavorable outcome with higher levels of γ' (p-value for trend = 0.06). Conclusions: Our study shows that absolute levels of fibrinogen γ' are increased in patients with intracerebral hemorrhage, but relative levels are similar in patients and controls, suggesting that the absolute rise in γ' is an acute phase response. http://repub.eur.nl/res/pub/26687/ 2011-07-01T00:00:00Z http://repub.eur.nl/res/pub/25804/ 2011-05-01T00:00:00Z It is well established that high plasma von Willebrand factor (VWF) levels are associated with an increased risk of arterial thrombosis, including myocardial infarction and ischemic stroke. As plasma VWF levels are, to a large extent, genetically determined, numerous association studies have been performed to assess the effect of genetic variability in the VWF gene (VWF) on VWF antigen and activity levels, and on the risk of arterial thrombosis. Genetic variations in other regulators of VWF, including the ABO blood group, ADAMTS-13, thrombospondin-1 and the recently identified SNARE protein genes, have also been investigated. In this article, we review the current literature as exploring the associations between genetic variations and the risk of arterial thrombosis may help elucidate the role of VWF in the pathogenesis of arterial thrombosis. However, as studies frequently differ in design, population and endpoint, and are often underpowered, it remains unclear whether VWF is causally related to the occurrence of arterial thrombosis or primarily mirrors endothelial dysfunction, which predisposes to atherosclerosis and subsequent arterial thrombosis. Nevertheless, current studies provide interesting results that do not exclude the possibility of VWF as causal mediator and justify further research into the relationship between VWF and arterial thrombosis. Large prospective studies are required to further establish the role of VWF in the occurrence of arterial thrombosis. http://repub.eur.nl/res/pub/26423/ 2011-05-01T00:00:00Z Background & Aims: Budd-Chiari syndrome (BCS) is a rare vascular liver disorder caused by thrombosis of the hepatic veins. In some patients, no known thrombophilic factor can be identified. This study aimed to identify novel factors that might play a role in thrombosis in BCS-patients by using a proteomic approach. Methods: The abundance of plasma clot-bound proteins was compared between nine BCS-patients and nine controls by using two-dimensional difference gel electrophoresis. The protein with the most significant decrease in patients was identified by mass spectrometry. Plasma levels of this protein were measured and the results were validated in a large cohort of BCS-patients. Results: A total of 26 protein spots significantly differed (p <0.001). The spot that decreased with the highest statistical significance in patients was identified by mass spectrometry as apolipoprotein A1 (apo A1). The mean level of apo A1 in the plasma of these BCS-patients (0.74 g/L) was also significantly lower than in controls (1.45 g/L, p = 0.002). This finding was validated in a large cohort of 101 BCS-patients and 101 controls (0.97 g/L vs. 1.32 g/L, p <0.0001). There was no major correlation between plasma levels of apo A1 and various liver function tests. Conclusions: BCS-patients show decreased clot-bound protein abundance and plasma levels of apo A1. Decreased levels of apo A1 may play a role in the etiology of thrombosis in BCS-patients and possibly in other patients with venous thrombosis. http://repub.eur.nl/res/pub/26484/ 2011-04-14T00:00:00Z The germline JAK2 46/1 haplotype has been associated with the development of JAK2V617F-positive as well as JAK2V617F-negative myeloproliferative neoplasms (MPNs). In this study we examined the role of the 46/1 haplotype in the etiology and clinical presentation of patients with splanchnic vein thrombosis (SVT), in which MPNs are the most prominent underlying etiological factor. The singlenucleotide polymorphism rs12343867, which tags 46/1, was genotyped in 199 SVT patients. The 46/1 haplotype was overrepresented in JAK2V617F-positive SVT patients compared with controls (P<.01). Prevalence of the 46/1 haplotype in JAK2V617F-negative SVT patients did not differ from prevalence in the controls. However, JAK2V617F-negative SVT patients with a proven MPN also exhibited an increased frequency of the 46/1 haplotype (P =.06). Interestingly, 46/1 was associated with increased erythropoiesis in JAK2V617F-negative SVT patients. We conclude that the 46/1 haplotype is associated with the development of JAK2V617F-positive SVT. In addition, our findings in JAK2V617F-negative SVT patients indicate an important role for the 46/1 haplotype in the etiology and diagnosis of SVT-related MPNs, independent of JAK2V617F, that requires further exploration. http://repub.eur.nl/res/pub/23850/ 2011-03-01T00:00:00Z Background: Von Willebrand disease (VWD) is the most frequent inherited bleeding disorder. Whether VWD is associated with health-related quality of life (HR-QoL) in children is unknown. Objectives: This nationwide cross-sectional study measured HR-QoL in children with moderate or severe VWD. Our primary aim was to compare HR-QoL of VWD patients with that of reference populations. Additionally, we studied the impact of bleeding phenotype and VWD type on HR-QoL. Methods: HR-QoL was assessed with the Infant/Toddler QoL Questionnaire (0-5 years) and Child Health Questionnaire (6-15 years), and compared with reference population scores. Multivariate analysis was used to evaluate the influence of type of VWD and bleeding phenotype on HR-QoL scores. Results: Preschool children (0-5 years, n=46) with VWD had lower HR-QoL scores for general health perceptions and parental time than reference populations. School children (6-15 years, n=87) with VWD had lower scores for physical functioning, role functioning - emotional/behavioral, general health perceptions, and physical summary. Type of VWD was associated with HR-QoL in school children for bodily pain, general health perceptions, parental emotion, family activities, and physical summary. Scores of children with type 3 VWD were, on average, 15 points lower than those of the reference population on the above-mentioned scales. A more severe bleeding phenotype was associated with a lower score on 11/15 physical, emotional and social scales. Conclusion: HR-QoL is lower in VWD children than in reference populations, in particular in school children. The negative impact of VWD is sensitive to type of VWD and bleeding phenotype; as well as physical scales, emotional and social scales are affected. http://repub.eur.nl/res/pub/23874/ 2011-03-01T00:00:00Z Background: Previous studies suggested that hypofibrinolysis is associated with increased risk of peripheral arterial disease. Thrombin activatable fibrinolysis inhibitor (TAFI) has been identified as an important inhibitor of fibrinolysis. The aim of our study was to assess the role of TAFI in young patients with peripheral arterial disease. Methods: In a single-center case-control study we measured plasma TAFI antigen levels and functional TAFI in consecutive young patients (men 18-45 years and women 18-55 years) with a first manifestation of peripheral arterial disease and compared these with a population-based control group. Results: A total of 47 peripheral arterial disease patients and 141 controls (mean age 43) were included. Intact TAFI antigen levels were significantly higher in patients with peripheral arterial disease (112.4 ± 21.1%) than in controls (104.9 ± 19.9%, p = 0.03). The risk of peripheral arterial disease increased with 18% (OR 1.18; CI 1.01-1.34) per 10% increase of TAFI antigen. Functional TAFI levels were slightly higher in patients compared to controls, however this difference was not significant. For individuals with the highest functional TAFI levels, above the 90th percentile, the increased risk for peripheral arterial disease was most pronounced (OR 3.1; CI 1.02-9.41). Conclusion: High TAFI levels are associated with increased risk of premature peripheral arterial disease. http://repub.eur.nl/res/pub/34237/ 2011-03-01T00:00:00Z In this review, we provide an overview of the risk factors for venous thromboembolism, focusing on hypercoagulability and hypofibrinolysis. In the first part of this review, we discuss the risk factors for commonly occurring venous thrombosis, in particular deep vein thrombosis and pulmonary embolism. In the second part, we provide an overview of the risk factors for the Budd-Chiari syndrome and portal vein thrombosis. These are rare, life-threatening forms of venous thromboembolism located in the splanchnic veins. There are many similarities in the risk profiles of patients with common venous thrombosis and splanchnic vein thrombosis. Inherited thrombophilia and hypofibrinolysis increase the risk of both common venous thrombosis and splanchnic vein thrombosis. However, there are also apparent differences. Myeloproliferative neoplasms and paroxysmal nocturnal hemoglobinuria have a remarkably high frequency in patients with thrombosis at these unusual sites but are rarely seen in patients with common venous thrombosis. There are also clear differences in the underlying risk factors for Budd-Chiari syndrome and for portal vein thrombosis, suggesting site specificity of thrombosis even within the splanchnic venous system. These clear differences in underlying risk factors provide leads for further research on the site specificity of venous thrombosis and the development of thrombosis at these distinct sites. Copyright http://repub.eur.nl/res/pub/31642/ 2011-01-27T00:00:00Z High levels of von Willebrand factor (VWF) are associated with an increased risk for cardiovascular disease (CVD). Although VWF levels are strongly heritable and genetic susceptibility is an important risk factor for CVD, information on the contribution of common VWF gene variants to VWF levels and CVD risk is limited. In a case-control study of 421 young patients with a first event of acute coronary heart disease (CHD) or ischemic stroke (IS), and 409 healthy control participants (men aged ≤ 45 years, women aged ≤ 55 years), 27 haplotypetagging single-nucleotide polymorphisms (ht-SNPs), covering the total common VWF gene variation, were selected and genotyped. The associations between these SNPs, VWF antigen (VWF:Ag) levels, VWF collagen-binding (VWF:CB) activity, and CVD risk was investigated. Two new associations were identified. For ht-SNP rs4764478 (intron 45), the increase in VWF:Ag levels and VWF:CB activity per minor allele was 0.082 (± 0.026) IU/mL (P = .001) and 0.096 (± 0.030) IU/mL (P = .002), respectively. ht-SNP rs216293 (intron 17) was associated with CVD risk (odds ratio, 1.44; 95% confidence interval [CI], 1.12-1.86 per minor allele). We confirmed the association between rs1063857 and CVD risk. Our data show that common variants in the VWF gene are associated with VWF levels and with the risk for CVD. http://repub.eur.nl/res/pub/22942/ 2011-01-01T00:00:00Z Multiple myeloma (MM) is associated with an increased risk of venous thromboembolic (VTE) complications. Aim of this study was to measure microparticle-associated tissue factor (MP-TF) activity in patients with newly diagnosed MM before and after chemotherapy and to investigate whether MP-TF activity is associated with VTE. MP-TF activity was assessed in 122 newly diagnosed MM patients who were eligible for combination chemotherapy. MP-TF activity levels (17.6 fM Xa/min [8.6-33.2] (median [IQR]) were higher in untreated MM patients compared to normal healthy volunteers (4.1 fM Xa/min [2.3-6.6], p <0.001). MP-TF activity prior to the start of treatment was not different between patients who developed a VTE during follow-up (n=15) and those who did not (n=107). In 75 patients in whom plasma was obtained before and after chemotherapy, MP-TF activity decreased significantly (from 17.4 [10.2-32.8] to 12.0 [7.0-18.5] fM Xa/min, P=0.006). MP-TF activity remained, however, elevated in patients who developed VTE (15.1 [10.3-25.2]), in contrast to patients not developing VTE (11.4 [7.0-25.2], P<0.001). In conclusion, MP-TF activity is increased in patients with MM. Whether MP-TF activity has a pathogenetic role in VTE in MM patients remains to be established in future studies. http://repub.eur.nl/res/pub/25489/ 2010-12-01T00:00:00Z Background - Elevated von Willebrand factor (VWF) plasma levels are associated with an increased risk of cardiovascular disease. A meta-analysis of genomewide association studies on VWF identified novel candidate genes, that is, syntaxin-binding protein 5 (STXBP5) and syntaxin 2 (STX2), which are possibly involved in the secretion of VWF. We investigated whether VWF antigen levels (VWF:Ag), VWF collagen-binding activity (VWF:CB) and the risk of arterial thrombosis are affected by common genetic variations in these genes. Methods and Results - In 463 young white subjects (men ≤45 years of age and women ≤55 years of age), who were included 1 to 3 months after a first event of arterial thrombosis, and 406 control subjects, we measured VWF:Ag and VWF:CB. Nine haplotype tagging single-nucleotide polymorphisms of STXBP5 and STX2 were selected and subsequently analyzed using linear regression with additive genetic models adjusted for age, sex, and ABO blood group. The minor alleles of rs9399599 and rs1039084 in STXBP5 were associated with lower VWF plasma levels and activity, whereas the minor allele of rs7978987 in STX2 was associated with higher VWF plasma levels and activity. The minor alleles of the single-nucleotide polymorphisms in STX2 were associated with a reduced risk of arterial thrombosis (rs1236: odds ratio, 0.73 [95% confidence interval, 0.59, 0.89]; rs7978987: odds ratio, 0.81 [95% confidence interval, 0.65, 1.00]; rs11061158: odds ratio, 0.69 [95% confidence interval, 0.55, 0.88]). Conclusions-Genetic variability in STXBP5 and STX2 affects both VWF concentration and activity in young individuals with premature arterial thrombosis. Furthermore, in our study, genetic variability in STX2 is associated with the risk of arterial thrombosis. However, at this point, the underlying mechanism remains unclear. http://repub.eur.nl/res/pub/22158/ 2010-10-01T00:00:00Z Background And Purpose-: Many studies have investigated the role of plasma von Willebrand factor level in coronary heart disease, but few have investigated its role in stroke. The aim of this study was to determine if von Willebrand factor levels are associated with the risk of stroke. Methods-: The study was part of the Rotterdam Study, a large population-based cohort study among subjects aged ≥55 years. We included 6 250 participants who were free from stroke at baseline (1997 to 2001) and for whom blood samples were available. Follow-up for incident stroke was complete up to January 1, 2005. Data were analyzed with Cox proportional hazards models adjusted for age and sex and additionally with models adjusted for other potential confounders including ABO blood group. A subgroup analysis was performed in participants without atrial fibrillation. Effect modification by sex was tested on a multiplicative and on an additive scale. Results-: During an average follow-up time of 5.0 years, 290 first-ever strokes occurred, of which 197 were classified as ischemic. The risk of stroke increased with increasing von Willebrand factor levels (age- and sex-adjusted hazard ratios per SD increase in von Willebrand factor level: 1.12 [95% CI, 1.01 to 1.25] for stroke, 1.13 [95% CI, 0.99 to 1.29] for ischemic stroke). Adjustments for additional confounders slightly attenuated the association. The association was also present in subjects without atrial fibrillation and did not differ between sexes. Conclusion-: High von Willebrand factor levels are associated with stroke risk in the general population. http://repub.eur.nl/res/pub/33009/ 2010-10-01T00:00:00Z The diagnostic workup in patients with ischaemic stroke often includes testing for prothrombotic conditions. However, the clinical relevance of coagulation abnormalities in ischaemic stroke is uncertain. Therefore, we reviewed what is presently known about the association between inherited and acquired coagulation disorders and ischaemic stroke, with a special emphasis on the methodological aspects. Good-quality data in this field are scarce, and most studies fall short on epidemiological criteria for causal inference. While inherited coagulation disorders are recognised risk factors for venous thrombosis, there is no substantial evidence for an association with arterial ischaemic stroke. Possible exceptions are the prothrombin G20210A mutation in adults and protein C deficiency in children. There is proof of an association between the antiphospholipid syndrome and ischaemic stroke, but the clinical significance of isolated mildly elevated antiphospholipid antibody titres is unclear. Evidence also suggests significant associations of increased homocysteine and fibrinogen concentrations with ischaemic stroke, but whether these associations are causal is still debated. Data on other acquired coagulation abnormalities are insufficient to allow conclusions regarding causality. For most coagulation disorders, a causal relation with ischaemic stroke has not been definitely established. Hence, at present, there is no valid indication for testing all patients with ischaemic stroke for these conditions. Large prospective population-based studies allowing the evaluation of interactive and subgroup effects are required to appreciate the role of coagulation disorders in the pathophysiology of arterial ischaemic stroke and to guide the management of individual patients. © 2010 The Authors. Journal compilation http://repub.eur.nl/res/pub/33146/ 2010-10-01T00:00:00Z Patients with malignancy frequently present with clinically suspected pulmonary embolism (PE). However, the safe and efficient combination of a clinical decision rule (CDR) and D-dimer test to rule out PE performs less well in patients with malignancy. We examined potential explanations and analysed whether elevating the D-dimer cut-off could improve the clinical utility. We used data on consecutive patients with suspected PE included in a multicenter management study. The performance of the Wells CDR and the D-dimer test was compared between patients with and without malignancy and multivariable analysis was used to compare the weights of the CDR variables. Furthermore, we combined the CDR (cut-off ≤4) with different D-dimer cut-off levels for the exclusion of PE. Of 3,306 patients with suspected PE, 475 (14%) had cancer. The Wells rule variables were less diagnostic in cancer patients. Increasing the D-dimer cut-off level to 700 μg/l for all ages or using an age-dependent cut-off resulted in an increase in the proportion of patients in whom PE could be excluded from 8.4% to 13% and 12%, respectively. The corresponding false-negative rates were 1.6% (95% confidence interval 0.3-8.7%) and 0.0% (0.0-6.3%). The Wells CDR and D-dimer perform less well in patients with suspected PE if they have cancer. Individual variables in the Wells rule are less diagnostic in cancer patients than in non-cancer patients with suspected PE. A CDR combined with an age-dependent D-dimer cut-off shows a modest improvement of the strategy in cancer patients. http://repub.eur.nl/res/pub/32800/ 2010-08-01T00:00:00Z The role of coagulation disorders in the pathogenesis of (recurrent) ischemic stroke is uncertain. Therefore, the clinical utility of screening patients with ischemic stroke for these conditions and the therapeutic implications of a detected coagulation disorder in a patient who experienced ischemic stroke are uncertain. We reviewed the currently available data on the relationship between various inherited and acquired coagulation abnormalities (factor V Leiden and prothrombin G20210A mutations, deficiencies of protein C, protein S and anti-thrombin, hyperhomocysteinemia, the antiphospholipid syndrome and increased levels of fibrinogen) and ischemic stroke. Based on the existing evidence we discuss the usefulness of screening stroke patients for prothrombotic conditions and current recommendations regarding the optimal management of ischemic stroke patients in whom a coagulation disorder is found. http://repub.eur.nl/res/pub/21120/ 2010-07-08T00:00:00Z This prospective study evaluated the risk of arterial thrombosis in 195 consecutive patients aged 18 to 65 years with newly diagnosed multiple myeloma (MM). All patients were treated with 3 cycles of VAD (vincristine, doxorubicin, and dexamethasone) or TAD (thalidomide-AD) or PAD (bortezomib-AD) in national trials, followed by high-dose melphalan and autologous stem cell transplantation. For a period of 522 patient-years, 11 of the 195 patients (5.6%) developed arterial thrombosis. The highest incidence was seen during induction chemotherapy courses. Median age at onset of arterial thrombosis was 59 years (range, 43-65 years). Hypertension and smoking were significantly associated with arterial thrombosis with a relative risk of 11.7 (2.23-61.2) and 15.2 (1.78-130), respectively. Factor VIII levels (FVIII:C) correlated significantly with age (P = .02) and higher International Scoring System (ISS) stage (P = .001). A higher FVIII:C was associated with arterial thrombosis (hazard ratio [HR] = 1.85; 95% confidence interval [CI] = 0.99-3.47) after adjustment for age, ISS score, and assigned treatment arm. MM patients have an increased risk for arterial thrombotic events during and after induction chemotherapy. Hypertension, smoking, and high factor VIII levels, possibly reflecting disease activity, contribute to the risk of arterial thrombosis. http://repub.eur.nl/res/pub/28549/ 2010-07-01T00:00:00Z Background: von Willebrand Disease (VWD) is the most frequent inherited bleeding disorder. It is unknown how this disorder affects quality of life. Objectives: This nationwide multicenter cross-sectional study determined health-related quality of life (HR-QoL) in adult patients with moderate or severe VWD, and assessed whether bleeding severity and type of VWD are associated with HR-QoL. Methods: HR-QoL was assessed using the Short Form (SF)-36, and bleeding severity was measured using the Bleeding Score (BS). Results: Five hundred and nine patients participated; 192 males and 317 females, median age and range 45 (16-87) and 47 (16-84) years, respectively. Compared with the general population, HR-QoL in VWD patients was lower in the vitality domain (61 vs. 66 P < 0.001 for females, 67 vs. 72 P < 0.001 for males). Patients with the most severe bleeding phenotype (highest quartile BS, BS > 17) had a lower HR-QoL in eight domains than patients with a less severe bleeding type (lowest quartile BS, BS < 7) in the univariate analysis. After adjustment for age, gender, co-morbidity and employment/educational status, a more severe bleeding phenotype was associated with lower scores on the domains of physical functioning, role limitations due to physical functioning, bodily pain, general health, social functioning and physical component summary. Conclusions: HR-QoL is lower in VWD patients compared with the general population. HR-QoL is strongly associated with bleeding phenotype. http://repub.eur.nl/res/pub/33006/ 2010-06-01T00:00:00Z Multiple organ failure is a common feature of pediatric meningococcal sepsis and is associated with an imbalance of coagulation and fibrinolysis. This is partly due to an increased secretion of prothrombotic ultralarge von Willebrand factor (VWF) as the result of vascular endothelial damage. Another factor that may contribute is ADAMTS13, which converts VWF into smaller, less active, VWF multimers and thus influences VWF activity in plasma. We investigated the role of ADAMTS13 and VWF in the severity and outcome of sepsis. In 58 children with severe meningococcal sepsis we measured ADAMTS13 activity and antigen, VWF collagen binding activity (VWF:CB) and antigen levels (VWF:Ag), VWF propeptide and factor VIII at different time points during their stay in the paediatric intensive care unit. In the acute phase, both ADAMTS13 activity and antigen were decreased (median 23.4% and 33.7% of normal, respectively) and VWF:CB and VWF:Ag levels were strongly increased (325% and 348%, respectively.) ADAMTS13 antigen (23.9% vs. 34.6%; p=0.06) and VWF:CB (240% and 340% p<0.001) were lower in non-survivors than in survivors. ADAMTS13 activity and VWF:CB were both correlated with the severity of the disease, as indicated by the Pediatric Risk of Mortality score (Rs= -0.38 and Rs= -0.50, p=0.01, respectively, p<0.001). In the acute phase of severe sepsis decreased levels of ADAMTS13 and increased levels of VWF are observed, and the changes are related to severity of disease and outcome. This may contribute to the formation of microthrombi and the severity of thrombotic sequelae of sepsis. http://repub.eur.nl/res/pub/20411/ 2010-02-05T00:00:00Z Rede, Rede uitgesproken bij de aanvaarding van het ambt van bijzonder hoogleraar met als leeropdracht hemostase en trombose aan het Erasmus MC, faculteit van de Erasmus Universiteit Rotterdam op 5 februari 2010 http://repub.eur.nl/res/pub/27438/ 2010-02-01T00:00:00Z http://repub.eur.nl/res/pub/33011/ 2010-02-01T00:00:00Z Novel P2Y12 inhibitors are in development to overcome the occurrence of atherothrombotic events associated with poor responsiveness to the widely used P2Y12 inhibitor clopidogrel. Cangrelor is an intravenously administered P2Y12 inhibitor that does not need metabolic conversion to an active metabolite for its antiplatelet action, and as a consequence exhibits a more potent and consistent antiplatelet profile as compared to clopidogrel. It was the objective of this study to determine the contribution of variation in the P2Y12 receptor gene to platelet aggregation after in vitro partial P2Y12 receptor blockade with the direct antagonist cangrelor. Optical aggregometry was performed at baseline and after in vitro addition of 0.05 and 0.25 μM cangrelor to the platelet-rich plasma of 254 healthy subjects. Five haplotype-tagging (ht)-SNPs covering the entire P2Y12 receptor gene were genotyped (rs6798347C>t, rs6787801T>c, rs9859552C>a, rs6801273A>g and rs2046934T>c [T744C]) and haplotypes were inferred. The minor c allele of SNP rs6787801 was associated with a 5% lower 20 μM ADP-induced peak platelet aggregation (0.05 μM cangrelor, p<0.05). Aa homozygotes for SNP rs9859552 showed 20% and 17% less inhibition of platelet aggregation with cangrelor when compared to CC homozygotes (0.05 and 0.25 μM cangrelor respectively; p<0.05). Results of the haplotype analyses were consistent with those of the single SNPs. Polymorphisms of the P2Y12 receptor gene contribute significantly to the interindividual variability in platelet inhibition after partial in vitro blockade with the P2Y12 antagonist cangrelor. http://repub.eur.nl/res/pub/27635/ 2010-01-14T00:00:00Z In Budd-Chiari syndrome (BCS), thrombosis develops in the hepatic veins or inferior vena cava. To study the relationship between hypofibrinolysis and BCS, we measured plasma levels of fibrinolysis proteins in 101 BCS patients and 101 healthy controls and performed a plasmabased clot lysis assay. In BCS patients, plasminogen activator inhibitor 1 (PAI-1) levels were significantly higher than in controls (median, 6.3 vs 1.4 IU/mL,. P < .001). Thrombin-activatable fibrinolysis inhibitor and plasmin inhibitor levels were lower than in controls (13.8 vs 16.9 μg/mL and 0.91 vs 1.02 U/L, both P < .001). Median plasma clot lysis time (CLT) was 73.9 minutes in cases and 73.0 minutes in controls (P = .329).Asubgroup of cases displayed clearly elevated CLTs. ACLT above the 90th or 95th percentile of controls was associated with an increased risk of BCS, with odds ratios of 2.4 (95% confidence interval, 1.1-5.5) and 3.4 (95% confidence interval, 1.2-9.7), respectively. In controls, only PAI-1 activity was significantly associated with CLT. Analysis of single nucleotide polymorphisms of fibrinolysis proteins revealed no significant differences between cases and controls. This case-control study provides the first evidence that an impaired fibrinolytic potential, at least partially caused by elevated PAI-1 levels, is related to the presence of BCS. http://repub.eur.nl/res/pub/16501/ 2009-11-01T00:00:00Z ADAMTS13 may play a role in arterial thrombosis by cleaving the highly active and thrombogenic ultralarge Von Willebrand Factor (VWF) multimers into less active VWF multimers. The aim was to investigate the relationship between plasma levels of ADAMTS13, VWF and genetic variation in the ADAMTS13 gene with cardiovascular disease. We performed a case-control study in 374 patients with a first-ever arterial thrombosis before the age of 45 years in males and 55 years in women. We included 218 patients with coronary heart disease (CHD), 109 patients with ischemic stroke (IS) and 47 patients with peripheral arterial disease (PAD) and 332 healthy population-based controls. ADAMTS13 and VWF levels were measured 1-3 months after the event. ADAMTS13 levels were associated with cardiovascular disease (OR antigen 5.1 (95% CI 3.1-8.5, p < 0.001) and OR activity 4.4 (95% CI 2.5-7.5, p < 0.001), in the lowest quartiles). VWF levels were associated with cardiovascular disease (OR antigen 2.1 (95% CI 1.3-3.3, p = 0.001) and OR activity 2.0 (95% CI 1.3-3.1, p = 0.003), in the highest quartile). Patients with combined low ADAMTS13 levels and high VWF levels had an odds ratio of 7.7 (95% CI 3.3-17.7) (p for trend <0.0001). No association was found between genetic variation in the ADAMTS13 gene with levels of ADAMTS13 or with risk of cardiovascular disease. In conclusion, levels of ADAMTS13 and VWF are strongly associated with the risk of cardiovascular disease. http://repub.eur.nl/res/pub/17267/ 2009-10-01T00:00:00Z Background/Aims: A well recognized cause of Budd-Chiari syndrome (BCS) is paroxysmal nocturnal hemoglobinuria (PNH). PNH is an acquired disorder of hematopoietic stem cells, characterized by intravascular hemolysis and venous thrombosis. Testing for this hematological disorder should be considered in all BCS patients. Methods: Using data from the EN-Vie study, a multi-center study of 163 patients with BCS, we investigated the relationship between BCS and PNH in 15 patients with combined disease and compared the results to 62 BCS patients in whom PNH was excluded. Results: Median follow-up for the study group (n = 77) was 20 months (range 0-44 months). BCS patients with PNH presented with a significantly higher percentage of additional splanchnic vein thrombosis (SVT) as compared to BCS patients without PNH (47% vs. 10%, p = 0.002). During follow-up, type and frequency of interventions for BCS was similar between both groups. Six patients with BCS and PNH were successfully treated with a transjugular intrahepatic portosystemic shunt (TIPS). Of 15 patients with PNH, six underwent allogenic stem cell transplantation after diagnosis of BCS. PNH was successfully cured in five cases. There was no significant difference in survival between BCS patients with and without PNH. Conclusions: This study shows that despite a higher frequency of additional SVT, short-term prognosis of BCS patients with PNH does not differ from BCS patients without PNH. Treatment with TIPS can be safely performed in patients with PNH. Stem cell transplantation appears to be a feasible treatment option for PNH in BCS patients. http://repub.eur.nl/res/pub/25276/ 2009-10-01T00:00:00Z Background-The clinical efficacy of clopidogrel is hampered by a large interindividual variability in platelet inhibition. Polymorphisms in the P2RY12 receptor gene have been suggested to contribute to this variability, but previous studies included a relatively small number of patients and incompletely covered the common variation in the P2RY12 gene. The aim of this study was to comprehensively investigate the possible association between common variation in the entire P2RY12 locus and the magnitude of residual on-clopidogrel platelet reactivity measured by 2 commonly used platelet function assays in a large cohort of patients. Methods and Results-A total of 1031 consecutive patients with coronary artery disease who were scheduled for elective percutaneous coronary interventions were enrolled. Platelet function was assessed by means of ADP-induced light-transmittance aggregometry and the VerifyNow P2Y12 assay. Six haplotype-tagging single nucleotide polymorphisms were carefully selected to comprehensively cover the total common variation in the P2RY12 gene and its flanking regulatory regions. Six common haplotypes were inferred from these haplotype-tagging single nucleotide polymorphisms (denoted A to F). Haplotype F was associated with significantly lower residual on-clopidogrel platelet reactivity compared with the reference haplotype A. The size of this effect per haplotype allele was approximately 5% aggregation in the ADP-induced light-transmittance aggregometry (P<0.05) and 11 P2Y12 reaction units in the VerifyNow P2Y12 assay (P<0.05). Conclusions-Common variation in the P2RY12 gene is a significant determinant of the interindividual variability in residual on-clopidogrel platelet reactivity in patients with coronary artery disease. (Circ Cardiovasc Genet. 2009;2:515-521.) http://repub.eur.nl/res/pub/17108/ 2009-08-05T00:00:00Z Background: Concentrations of inflammatory and hemostatic variables are influenced by biological variation, which is the natural within-subject variation over time. Objectives: The aim of this study was to determine fibrinogen, C-reactive protein (CRP), platelet aggregation, thrombin generation and prothrombin time (PT): (i) the number of repeated measurements needed to obtain the true habitual concentration of an individual; (ii) the recommended analytical imprecision for diagnosis and monitoring; (iii) the recommended analytical bias; (iv) the contribution of analytical imprecision to test result variability; (v) the index of individuality; (vi) the reference change value; and (vii) the seasonal variation. Subjects and methods: We collected 520 blood samples over a 1-year period from 40 healthy individuals, and determined the between-subject, within-subject and seasonal variation in fibrinogen, CRP, platelet aggregation, thrombin generation and PT. Results: One or two repeated measurements were sufficient to establish the true habitual concentration, except for platelet aggregation and peak thrombin generation, where at least four and nine repeated measurements were needed, respectively. For diagnosis, the maximal recommended coefficient of analytical variation (CV) was 4%-27%, except for CRP (77.7%). For monitoring, these CVs were on average 3% lower. Recommended analytical bias varied between 1.7% and 33.2%. Finally, seasonal variation was observed in concentrations of fibrinogen and thrombin generation, which could explain approximately 11% of their total variation. Conclusion: This study provides insights into the biological variability of selected inflammatory and hemostatic markers, which can be used for sample size calculations and to determine the analytical quality specifications for their respective assays. http://repub.eur.nl/res/pub/24289/ 2009-07-01T00:00:00Z Objective laboratory tools are needed to monitor developing organ damage in sickle cell disease (SCD). Circulating endothelial cells (CECs) are indicative of vascular injury. We determined whether elevated CEC can be detected in asymptomatic SCD with the CellSearch system and whether the CEC count is related to clinical and blood-based biomarkers of disease severity. Fifteen consecutive clinically asymptomatic HbSS patients and 15 matched HbAA controls were analyzed for CEC counts, laboratory parameters of disease severity (Hb, leukocyte counts, HbF%), plasma levels of markers for endothelial activation (sVCAM-1, VWF:Ag) and of endogenous inhibitors of nitric oxide synthase (asymmetrical dimethylarginine [ADMA]). CEC counts were significantly higher in patients (12 cells/mL, IQR 8-29) as compared to controls (4 cells/mL, 3-10) (P = 0.007). CEC counts were significantly higher in patients with pulmonary hypertension (PHT) (P = 0.015), and increased with increasing number of affected organs (0-4 involved organs, P = 0.002). No significant correlations between CEC and any other laboratory parameter were detected. In conclusion, CECs could prove to be an important new tool for assessing developing vasculopathy and organ damage in SCD. http://repub.eur.nl/res/pub/16510/ 2009-05-29T00:00:00Z Background and objectives: Thrombin activatable fibrinolysis inhibitor (TAFI) attenuates fibrinolysis and may therefore contribute to the pathophysiology of arterial thrombosis. The aim of the present study was to elucidate the pathogenetic role of TAFI levels and genotypes in young patients with arterial thrombosis. Patients and methods: In a case-control study, 327 young patients with a recent first-ever event of coronary heart disease (CHD subgroup) or cerebrovascular disease (ischemic stroke subgroup) and 332 healthy young controls were included. TAFI levels [intact TAFI, activation peptide (TAFI-AP) and (in)activated TAFI (TAFIa(i)] and TAFI activity were measured and genetic variations in the TAFI gene (-438G/A, 505G/A and 1040C/T) were determined. Results: In the total group of patients, TAFIa(i) levels were higher (145.1 ± 37.5%) than in controls (137.5 ± 31.3%, P = 0.02). Plasma levels of intact TAFI, TAFI-AP and TAFI activity were similar in patients and controls. In the CHD subgroup (n = 218), intact TAFI levels were higher (109.4 ± 23.0%) than in controls (102.8 ± 20.7%, P = 0.02). In 325Ile/Ile homozygotes, lower TAFI levels and a decreased risk of arterial thrombosis were observed (OR 0.58, 95% CI 0.34-0.99) compared with patients with the common 325Thr/Thr genotype. This association was most evident in CHD patients (OR 0.48, 95% CI 0.26-0.90). Haplotype analyses supported a role for the Thr325Ile polymorphism. Conclusions: TAFIa(i) levels were higher in patients with cardiovascular disease. Furthermore, the TAFI 325Thr/Ile polymorphism was associated with lower TAFI levels and with the risk of cardiovascular disease in young patients, especially in CHD. http://repub.eur.nl/res/pub/18148/ 2009-04-01T00:00:00Z The relationship between defective fibrinolysis and arterial thrombosis is uncertain. The evaluation of the plasma fibrinolytic potential might provide stronger evidence linking fibrinolysis to arterial thrombosis than the evaluation of the individual fibrinolytic factors. We determined the plasma fibrinolytic potential of 335 young survivors of a first arterial thrombosis, including coronary artery disease (n = 198), ischaemic stroke (n = 103) and peripheral artery disease (n = 34), enrolled in a population-based case-control study and of 330 healthy individuals. Patients had significantly higher clot lysis times (CLTs) than the controls. Odds ratios (ORs) were calculated as a measure of relative risk. The OR for arterial thrombosis was determined in these subjects who had a CLT above the 60th, 70th, 80th, 90th and 95th percentiles of the values found in the control subjects. We found a progressive increase in risk of arterial thrombosis in subjects with hypofibrinolysis (OR: 1·7, 2·0, 2·3, 2·3 and 2·9, respectively). Relative risk estimates obtained in the whole group were comparable those obtained in the event-subgroups. In conclusion, a low plasma fibrinolytic potential, found in 10% of the population, increases the relative risk of arterial thrombosis twofold. This points to an important contribution of hypofibrinolysis to the burden of arterial thrombosis. http://repub.eur.nl/res/pub/18434/ 2009-03-01T00:00:00Z Background: Quantitative D-Dimer tests are established methods in the non-invasive diagnostic management to rule out venous thromboembolism (VTE). The diagnostic performance and the clinical efficiency different D-Dimer assays in the exclusion of pulmonary embolism (PE) have not yet been compared in a clinical outcome study. Objective: Evaluation of the efficiency and safety of excluding the diagnosis of PE with two different quantitative D-Dimer assays in consecutive patients with clinically suspected PE. Patients and Methods: We studied the VTE-failure rate of 2206 consecutive patients with an unlikely clinical probability in whom VIDAS or Tinaquant D-Dimer tests were performed. Results: The prevalence of PE in 1238 patients whose D-Dimer level was analyzed with Tinaquant assay was 11%. The VIDAS assay group consisted of 968 patients with a PE prevalence of 13%. The VIDAS assay had a sensitivity of 99.2% (95%CI; 96- > 99.9%), the Tinaquant assay of 97.3% (95%CI; 93 -99%). The negative predictive value (NPV) in the Tinaquant assay group was 99.4% (95%CI 98-99.8%) in comparison to 99.7% (95%CI 99-> 99.9%) in the VIDAS assay group. During 3 month of follow-up, there were no fatal cases of PE among patients with normal D-Dimer and unlikely clinical probability in both D-Dimer assay groups. In addition, the test efficiency of Tinaquant assay was significantly higher in comparison to VIDAS assay (52% vs 42%, p < 0.001). Conclusion: Both Tinaquant and VIDAS D-Dimer tests perform equally well in combination with an unlikely clinical probability in excluding PE. The Tinaquant test was shown to be more efficient. http://repub.eur.nl/res/pub/16759/ 2009-01-01T00:00:00Z http://repub.eur.nl/res/pub/16824/ 2009-01-01T00:00:00Z Background: The Budd-Chiari syndrome (BCS) is hepatic venous outflow obstruction. What is known about the syndrome is based on small studies of prevalent cases. Objective: To characterize the causes and treatment of incident BCS. Design: Consecutive case series of patients with incident BCS, enrolled from October 2003 to October 2005 and followed until May 2006. Setting: Academic and nonacademic hospitals in France, Spain, Italy, Great Britain, Germany, Belgium, the Netherlands, Portugal, and Switzerland. Patients: Persons older than 16 years with definite hepatic outflow obstruction diagnosed by imaging. Persons with hepatic outflow obstruction due to heart failure, sinusoidal obstruction syndrome, cancer, or liver transplantation were excluded. Measurements: Signs and symptoms; laboratory and imaging findings; diagnosis; treatment; and overall, transplantation-free, and intervention-free survival. Results: 163 incident cases of BCS were identified. Median follow-up was 17 months (range, 0.1 to 31 months). Most patients (84%) had at least 1 thrombotic risk factor, and many (46%) had more than 1; the most common was myeloproliferative disorders (49% of 103 tested patients). Patients were mainly treated with anticoagulation (140 patients [86%]), transjugular intrahepatic portosystemic shunting (56 patients [34%]), or liver transplantation (20 patients [12%]), and 80 patients (49%) were managed noninvasively. Only 3 patients underwent surgical shunting. The survival rate was 87% (95% CI, 82% to 93%) at 1 year and 82% (CI, 75% to 88%) at 2 years. Limitation: Treatment was not standardized across all centers, and data on important clinical variables were missing for some patients. Conclusion: Most patients with BCS have at least 1 thrombotic risk factor, and many have more than 1; myeloproliferative disorders are most common. One- and 2-year survival rates are good with contemporary management, which includes noninvasive therapies (anticoagulation and diuretics) and invasive techniques. Transjugular intrahepatic portosystemic shunting seems to have replaced surgical shunting as the most common invasive therapeutic procedure. Primary Funding Source: Fifth Framework Programme of the European Commission. http://repub.eur.nl/res/pub/32500/ 2008-12-01T00:00:00Z http://repub.eur.nl/res/pub/14245/ 2008-12-01T00:00:00Z Background: Protein Z (PZ) is a vitamin K-dependent plasma protein that plays a role in both pro-and anticoagulant pathways, but its exact physiological function remains unclear. The aim of this study was to determine the association between the G79A PZ gene polymorphism in intron F, PZ levels and the occurrence of ischemic stroke. Methods: We performed a case-control study in 118 Caucasian patients with first ever ischemic stroke or TIA confirmed by CT, and 113 age-and sex-matched population controls. Venous blood samples for PZ levels were collected 7 to 14 days and 3 months after stroke onset. Estimates of relative risk (odds ratios) were adjusted for vascular risk factors. Results: The adjusted relative risk of ischemic stroke associated with PZ levels in the lowest quartile versus the highest quartile was 3.0 (95% CI: 1.1-8.7) at 7-14 days, and 5.1 (95% CI: 1.2-21.9) at 3 months after the stroke. PZ levels in the convalescent sample were significantly lower than in the acute sample. In the convalescent sample, odds ratios increased with lower quartiles of protein Z level (test for trend p = 0.02). Thirty-nine patients (33%) and 32 (28%) controls were heterozygous for the G79A PZ gene polymorphism and 4 (3%) patients and 4 (4%) controls had the AA-genotype. The PZ levels were significantly lower in subjects with the AA-genotype and intermediate in heterozygote subjects. The odds ratio of ischemic stroke associated with A-allele carriers versus GG-homozygotes was 1.2 (95% CI: 0.7-2.1). Conclusion: No association between the G79A PZ gene polymorphism and the occurrence of stroke was observed. However, low PZ levels are independently associated with an increased risk of ischemic stroke. http://repub.eur.nl/res/pub/29043/ 2008-12-01T00:00:00Z Ischemic stroke is associated with leucocyte activation. Activated leucocytes release elastase, an enzyme that can degrade fibrinogen. Fibrinogen elastase degradation products (FgEDP) may serve as a specific marker of elastase proteolytic activity. In a case-control study of 111 ischemic stroke patients and 119 controls, significantly higher FgEDP levels were observed in cases than in controls, both in the acute phase and in the convalescent phase. Results were only slightly affected by adjustment for cardiovascular risk factors, C-reactive protein and fibrinogen. Our findings suggest that FgEDP might be involved in the pathogenesis of stroke. http://repub.eur.nl/res/pub/15148/ 2008-09-12T00:00:00Z http://repub.eur.nl/res/pub/32405/ 2008-09-01T00:00:00Z Dose-response relationship was studied between PFA-100 closure times (PFA CTs) and factor (F)VIII-von Willebrand factor (VWF) parameters in patients with von Willebrand disease (VWD) type 1 and type 2 before and after treatment with DDAVP (n=84) or FVIII/VWF concentrate (n=38). DDAVP treatment of patients with VWD type 1 normalised the PFA CTs by increasing VWF levels to normal. Of the 14 patients with VWD type 2, PFA CTs did not normalize in eight. Haemate-P substitution in patients with VWD type 1 induced a less favourable response as compared to DDAVP, because PFA CTs did not correct in all patients. Of 12 patients with VWD type 2 treated with Haemate-P, six showed a correction of PFA CTs (<250 sec), which correlated with the normalisation of the VWF CB/Ag ratio. In-vitro studies were performed by using whole blood of patients with VWD and adding various amounts of FVIII/VWF concentrate. Addition of Haemate-P induced an increase of the VWF CB/Ag ratio from 0.30 to 0.70 in blood of patients with VWD type 2 with correction of the PFA CTs. Immunate did not result in an increase of VWF CB/Ag ratio in blood of VWD type 2 patients, and the PFA CTs remained prolonged. We conclude that PFA-100 might be an adequate instrument not only for diagnosis but also for monitoring of DDAVP responses and FVIII/VWF substitution of patients with VWD type 1 and 2, but this is dependent upon the type of VWD and the concentrate used. http://repub.eur.nl/res/pub/15975/ 2008-08-26T00:00:00Z http://repub.eur.nl/res/pub/32339/ 2008-08-01T00:00:00Z Haplotypes of the fibrinogen gamma and alpha (FGG and FGA) genes are associated with the structure of the fibrin network and may therefore influence the risk of stroke. We investigated the relationship between common variation in these genes with ischemic and haemorrhagic stroke. The study was based on 6,275 participants of the prospective population-based Rotterdam Study who at baseline (1990-1993) were aged 55 years or over, free from stroke, and had successful assessment of at least one FGG or FGA single nucleotide polymorphisms (SNP). Common haplotypes were estimated using seven tagging SNPs across a 30 kb region containing the FGG and FGA genes. Follow-up for incident stroke was complete until January 1, 2005. Associations between constructed haplotypes and risk of stroke were estimated with an age- and sex-adjusted logistic regression model. We observed 668 strokes, of which 393 were ischemic and 62 haemorrhagic, during a median follow-up time of 10.1 years. FGG+FGA haplotype 3 (H3) was associated with an increased risk of ischemic stroke (odds ratio [OR] 1.36, 95% confidence interval [CI] 1.09-1.69) and the risk estimate for hemorrhagic stroke was 0.71 (95% CI 0.46-1.09) compared to the most frequent H1. The FGG and FGA genes were not associated with stroke or its subtypes when analyzed separately. In conclusion, risk of ischemic stroke was higher in FGG+FGA H3 than in H1. The results suggested that an opposite association may exist for haemorrhagic stroke. http://repub.eur.nl/res/pub/29975/ 2008-08-01T00:00:00Z Objective. To determine the utility of high quantitative D-dimer levels in the diagnosis of pulmonary embolism. Methods. D-dimer testing was performed in consecutive patients with suspected pulmonary embolism. We included patients with suspected pulmonary embolism with a high risk for venous thromboembolism, i.e. hospitalized patients, patients older than 80 years, with malignancy or previous surgery. Presence of pulmonary embolism was based on a diagnostic management strategy using a clinical decision rule (CDR), D-dimer testing and computed tomography. Results. A total of 1515 patients were included with an overall pulmonary embolism prevalence of 21%. The pulmonary embolism prevalence was strongly associated with the height of the D-dimer level, and increased fourfold with D-dimer levels greater than 4000 ng mL-1compared to levels between 500 and 1000 ng mL-1. Patients with D-dimer levels higher than 2000 ng mL-1and an unlikely CDR had a pulmonary embolism prevalence of 36%. This prevalence is comparable to the pulmonary embolism likely CDR group. When D-dimer levels were above 4000 ng mL-1, the observed pulmonary embolism prevalence was very high, independent of CDR score. Conclusion. Strongly elevated D-dimer levels substantially increase the likelihood of pulmonary embolism. Whether this should translate into more intensive diagnostic and therapeutic measures in patients with high D-dimer levels irrespective of CDR remains to be studied. http://repub.eur.nl/res/pub/29434/ 2008-07-01T00:00:00Z Background: Venous thromboembolism (VTE) occurs frequently in multiple myeloma patients, especially during induction treatment with thalidomide in combination with anthracyclines and/or dexamethasone. Several coagulation abnormalities have been described in untreated myeloma patients, but these have not been prospectively evaluated during and after treatment. Patients and methods: We performed a prospective study in 138 multiple myeloma patients in whom coagulation factor levels were evaluated longitudinally before, during induction and after intensification. Patients were randomized to induction treatment consisting of adriamycin and dexamethason, in combination with either vincristin (VAD), thalidomide (TAD), or bortezomib (PAD) followed by high-dose melphalan (HDM) and autologous stem cell transplant (ASCT). Results: Factor VIII:C (FVIII:C) and von Willebrand factor (VWF) were significantly elevated before treatment (median FVIII:C 2.26 U/ml, VWF:Ag 1.95 U/ml). Irrespective of the type of induction regimen, these variables increased strongly during induction therapy (FVIII:C 2.55 U/ml and VWF:Ag 2.96 U/ml). Fibrinogen also showed a significant increase after induction therapy (3.5 g/l pre-treatment and 4.0 g/l after treatment, respectively, P < 0.001). This was significantly higher in TAD than VAD treated patients. Three to six month after ASCT levels of VWF and FVIII:C had decreased to values lower than observed before treatment (1.71 and 1.67 U/ml respectively). There was no correlation between the increased levels at start and the response of multiple myeloma to treatment. High levels of VWF, fibrinogen and FVIII:C before start of treatment were significantly associated with mortality. Fourteen patients (10%) developed a venous thrombotic event (VTE). The coagulation factor abnormalities before and during treatment were not associated with the development of VTE. Conclusion: During induction treatment several changes in coagulation factor levels are observed, which may result in a prothrombotic state. Larger studies are required to establish whether the changes in these coagulation factors during induction treatment contribute to the increased risk of venous thromboembolism in multiple myeloma patients. http://repub.eur.nl/res/pub/28912/ 2008-05-15T00:00:00Z Myeloproliferative diseases (MPDs) represent the commonest cause of splanchnic vein thrombosis (SVT), including Budd- Chiari syndrome (BCS) and portal vein thrombosis (PVT), but their diagnosis is hampered by changes secondary to portal hypertension, while their influence in the outcome of SVT remains unclear. We assessed the diagnostic and prognostic value of JAK2 and MPL515 mutations in 241 SVT patients (104 BCS, 137 PVT). JAK2V617F was found in 45% of BCS and 34% of PVT, while JAK2 exon 12 and MPL515 mutations were not detected. JAK2V617F was found in 96.5% of patients with bone marrow (BM) changes specific for MPD and endogenous erythoid colonies, but also in 58% of those with only one feature and in 7% of those with neither feature. Stratifying MPD diagnosis first on JAK2V617F detection would have avoided BM investigations in 40% of the patients. In BCS, presence of MPD carried significantly poorer baseline prognostic features, required hepatic decompression procedures earlier, but had no impact on 5-year survival. Our results suggest that JAK2V617F testing should replace BM investigations as initial test for MPD in patients with SVT. Underlying MPD is associated with severe forms of BCS, but current therapy appears to offset deleterious effects of MPD on the medium-term outcome. http://repub.eur.nl/res/pub/30504/ 2008-04-01T00:00:00Z Background: A 22-year-old female presented with edema, diarrhea, hypoalbuminemia and pancytopenia. She had previously been diagnosed with congenital disorder of glycosylation type Ib, and had a history of congenital hepatic fibrosis, portal hypertension and esophageal varices. In the past she had refused mannose therapy because of associated diarrhea and abdominal pain. Investigations: Laboratory examinations, abdominal ultrasonography, bacterial and viral cultures of blood, urine and stools, double-balloon enteroscopy and fecal excretion test using51Cr-labeled albumin. Diagnosis: Protein-losing enteropathy. Management: Infusion of albumin followed by intravenous and subcutaneous therapy with unfractionated heparin. http://repub.eur.nl/res/pub/29230/ 2008-03-01T00:00:00Z BACKGROUND AND PURPOSE - To determine the contribution of fibrinogen γ′ levels and FGG haplotypes to ischemic stroke. METHODS - Associations between fibrinogen γ′ levels, fibrinogen γ′/total fibrinogen ratio, and FGG haplotypes with the risk of ischemic stroke were determined in 124 cases and 125 controls. RESULTS - Fibrinogen γ′/total fibrinogen ratio was higher in patients than in controls during the acute phase of the stroke and lower in the convalescent phase 3 months after the stroke. FGG haplotype 3 (H3) was associated with a reduced risk of ischemic stroke (odds ratio 0.60; 95% CI, 0.38 to 0.94), but not with the fibrinogen γ′/total fibrinogen ratio. In contrast, FGG-H2 was associated with a decreased fibrinogen γ′/total fibrinogen ratio, but not with risk of stroke. CONCLUSIONS - Fibrinogen γ′/total fibrinogen ratio is associated with ischemic stroke, especially in the acute phase of the disease. In addition, FGG-H3 haplotype appears to be protective against ischemic stroke. http://repub.eur.nl/res/pub/29262/ 2008-03-01T00:00:00Z http://repub.eur.nl/res/pub/30102/ 2008-03-01T00:00:00Z The platelet receptor P2Y12 (gene symbol P2RY12) is involved in several processes that contribute to restenosis after percutaneous coronary interventions (PCI). Therefore, common variation in the P2Y12 gene may serve as a useful marker for risk stratification. We studied whether common variation in the platelet receptor P2Y12 gene affects the risk of restenosis after PCI. Comprehensive coverage of common variation in the P2Y12 gene was obtained by genotyping five haplotype-tagging SNPs (ht-SNPs) in 2,062 PCI-treated patients who received a stent and participated in the GENetic DEterminants of Restenosis (GENDER) Study. Haplotypes were inferred and their association with target vessel revascularization (TVR) was studied. Seven P2Y12 haplotypes were identified with an allelic frequency above 5% (designated here H1 to H7) of which two (H5 and H7) were associated with a higher risk of TVR (hazard ratios [HR] = 1.4, 95% confidence interval [CI] = 1.0-2.0; and HR = 1.6, 95% CI = 1.2-2.0, respectively) than the reference P2Y12 haplotype (H1), which contains the common alleles of all five P2Y12 ht-SNPs. Our study shows that common variation in the P2Y12 gene predicts restenosis in PCI-treated patients. http://repub.eur.nl/res/pub/28976/ 2008-01-01T00:00:00Z High D-dimer levels are predictors of death in patients with pulmonary embolism (PE), as are more proximally located, larger emboli. The direct link between these three has not yet been described. A cohort of 674 consecutive patients with confirmed PE was studied. Patients were followed up for 3 months. D-dimer levels were measured only in patients with an unlikely clinical probability (n = 262). The odds ratio (OR) for death of all variables was calculated. Multivariate analysis was performed to identify independent risk factors for mortality. The best predictive D-dimer cut-off point for mortality was a concentration >3000 ng/ml FEU (OR 7.29). High D-dimer levels were correlated with active malignancy and age over 65 years, both being indicators of 3-month mortality. High D-dimer levels were also correlated with centrally located pulmonary emboli and 15-d mortality. The combination of high D-dimer levels and central emboli increased early mortality risk by 2.2. High D-dimer levels in patients with an unlikely clinical probability were associated with fatal outcome after PE. Centrally located pulmonary emboli were associated with higher D-dimer levels and worse 15-d mortality. Active malignancy, being an inpatient at time of diagnosis and age over 65 years were associated with higher D-dimer levels and worse 3-month survival. http://repub.eur.nl/res/pub/35932/ 2007-07-01T00:00:00Z In most patients with acute or chronic liver failure, extensive changes in all pathways contributing to hemostasis are found. These hemostatic alterations concern both pro- and antihemostatic pathways, and therefore the net result of the hemostatic dysbalance is unclear. Although it is generally believed that patients with liver disease have a hemostasis-related bleeding tendency, this concept is challenged in recent literature. Although the bleeding problems in patients with liver disease are obvious, the clinically most relevant bleeding episodes, i.e., bleeding from ruptured varices or ulcers, are due to vascular abnormalities and portal hypertension, and not to an abnormal hemostatic system. Moreover, patients with liver disease sometimes experience thrombosis of the portal vein or hepatic artery, which is in part attributed to hypercoagulation. In addition, a substantial part of the patients with liver disease undergoing liver transplantation can nowadays undergo this major surgical procedure, which involves significant hemostatic challenges, without transfusion of blood products. Therefore, the recent debate on the presence of a major hemostatic defect in patients with liver disease seems justified. This paper will review the hemostatic changes that occur in acute and chronic liver failure, and will review hemostasis testing and reversal of coagulopathy in these patients. Copyright http://repub.eur.nl/res/pub/37002/ 2007-07-01T00:00:00Z Purpose: An increased incidence of thromboembolic complications has been observed in multiple myeloma (MM), especially when patients are treated with anthracycline-based chemotherapy. In patients with MM, plasma levels of several prothrombotic coagulation factors are increased, and this can contribute to the prothrombotic state of these patients. Recently, an increased thrombosis risk has also been described for other plasma cell disorders (PCDs), such as monoclonal gammopathy of uncertain significance (MGUS) and systemic amyloidosis. The aim of this study was to analyze prothrombotic coagulation disorders in patients with paraprotein-producing B-cell disorders, such as MGUS, systemic amyloidosis, Waldenstrom's macroglobulinemia, and MM. Patients and Methods: An increase in factor VIII and von Willebrand factor was observed in patients with MGUS and systemic amyloidosis that was similar to increases seen in patients with untreated MM. The highest levels were observed in patients with systemic amyloidosis. Results: We observed several coagulation abnormalities in patients with different PCDs. Conclusion: These prothrombotic changes in patients with MM, systemic amyloidosis, and Waldenström's macroglobulinemia might be causally related to the observed incidence of venous thromboembolism in these forms of PCDs. http://repub.eur.nl/res/pub/36087/ 2007-06-01T00:00:00Z It is unknown whether strategies validated for diagnosing pulmonary embolism (PE) are valid in patients with a history of PE. It was the objective of this study to investigate whether a diagnostic algorithm consisting of sequential application of a clinical decision rule (CDR), a quantitative D-dimer test and computed tomography (CT) safely ruled out a clinical suspicion of acute recurrent PE. Data were obtained from a diagnostic outcome study of patients suspected of PE. Acute recurrent PE was ruled out by an unlikely probability of PE (CDR score ≤4 points) combined with a normal D-dimer test (≤500 ng/ml) or by a normal CT in all other patients. The primary outcome was the incidence of acute recurrent venous thromboembolism during three months of follow-up in patients with normal tests and not treated with anticoagulants. Of 3,306 patients suspected of acute PE, 259 patients (7.8%) had a history of PE of whom 234 were not treated with anticoagulants. The probability of PE was unlikely in 82 of 234 patients (35%), and 42 had a normal D-dimer test (18%), excluding recurrent PE. None of these patients had a thrombotic event during follow-up (0%, 95%Cl: 0-6.9). A CT was indicated in all other patients (192) and ruled out recurrent PE in 127 patients (54%). Only one patient with a negative CT had a fatal recurrent PE during follow-up (0.8%; 95%Cl: 0.02-4.3). In conclusion, this prospective study demonstrates the safety of ruling out a clinical suspicion of acute recurrent PE by a simple diagnostic algorithm in patients with a history of PE. http://repub.eur.nl/res/pub/35529/ 2007-03-15T00:00:00Z The glycosylation profile of von Willebrand factor (VWF) is known to strongly influence its plasma levels. VWF contains several carbohydrate structures, including O-linked glycans that primarily consist of sialylated T antigen (NeuAc(α2-3)Gal-(β1-3)-[NeuAc(α2-6)]GalNAc). It is not yet known whether O-linked carbohydrates affect VWF levels. We developed an immunosorbent assay based on neuraminidase incubation allowing subsequent binding of peanut agglutinin (PNA) to desialylatedO-linked T antigen on VWF. An inverse relation was found between PNA binding and VWF antigen levels in healthy individuals (n = 111; Pearson rank - -0.43; P < .001). A similar inverse association was observed in randomly selected plasma samples from our diagnostic laboratory: 252% ± 125% for VWF levels less than 0.5 U/mL (n = 15); 131% ± 36% for VWF levels between 0.5 and 1.5 U/mL (n = 32); and 92% ± 40% for VWF levels more than 1.5 U/mL (n = 19). Reduced or increased PNA binding was also observed in patients with increased (liver cirrhosis) or reduced (von Willebrand disease [VWD] type 1) VWF antigen levels, respectively. VWD type 1 patients further displayed increased ratios of propeptide over mature VWF antigen levels (0.38 ± 0.18 versus 0.17 ± 0.03 for patients and controls, respectively; P < .001), which is indicative of reduced VWF survival in these patients. Of interest, a linear relation between PNA binding and propeptide/VWF ratio was observed (Spearman rank = 0.47), suggesting a potential association between O-linked glycosylation and VWF survival. Finally, we detected a marked decrease in PNA binding in post-DDAVP (1-deamino-8-D- arginine vasopressin) samples from various patients, indicating that the O-linked glycosylation profile of VWF stored in endothelial storage organelles may differ from circulating VWF. http://repub.eur.nl/res/pub/36129/ 2007-02-01T00:00:00Z http://repub.eur.nl/res/pub/36142/ 2007-02-01T00:00:00Z Splanchnic vein thrombosis (SVT) has been associated with a hypercoagulable state. Thrombin-activatable fibrinolysis inhibitor (TAFI) may contribute to a hypercoagulable state, and therefore we were interested in the role of TAFI in SVT. Since the disease is frequently associated with liver insufficiency, which affects plasma levels of TAFI, we studied the role of variation in the TAFI gene in SVT. In a multicenter case-control study on 118 patients with SVT (39 Budd-Chiari syndrome and 85 portal vein thrombosis) and 118 population-based controls, the relationship of SVT with single nucleotide polymorphisms (SNPs) and haplotypes in the TAR gene (- 438G/A, Ala I47Thr, Thr3251le and 1583A/T) was determined.The risk for SVT was decreased (OR 0.2, 95% Cl 0. 1-0.7) in 147Thr/Thr homozygotes and slightly, but not significantly, increased in carriers of the 3251le allele (OR 1.6, 95%Cl 0.9-2.7). Haplotype analysis confirmed that the Ala 147Thr SNP has the strongest association with risk of SVT. In conclusion, genetic variation in the TAR gene is associated with risk of SVT, suggesting a role for TAFI in the pathogenetic mechanism of SVT. http://repub.eur.nl/res/pub/22479/ 2005-01-01T00:00:00Z BACKGROUND: To determine whether -148 C/T fibrinogen gene promoter polymorphism increases stroke risk by modifying the fibrinogen level. DESIGN: A case-control study of patients with first ever ischaemic stroke, confirmed by computed tomography. METHODS: Venous blood samples were collected for fibrinogen and routine coagulation tests one week after the stroke, and after three months in about half the patients. Population controls were age and sex matched. -148 C/T fibrinogen polymorphism was determined by polymerase chain reaction followed by digestion with restriction enzymes HindIII/AluI. RESULTS: There were 124 patients and 125 controls, mean age 56 years (range 18 to 75); 34 patients (27%) and 41 controls (33%) were heterozygous for -148 C/T fibrinogen polymorphism; six patients (5%) and five controls (4%) had the T/T genotype. The odds ratio of ischaemic stroke associated with CC homozygotes v T carriers was 0.8 (95% confidence interval, 0.5 to 1.4). Relative risk for ischaemic stroke associated with fibrinogen levels in the highest quartile was 3.9 (1.9 to 8.4) at one week, decreasing to 1.4 (0.6 to 3.3) at three months. CONCLUSIONS: -148 C/T fibrinogen gene polymorphism was not a strong risk factor for ischaemic stroke. High fibrinogen levels early after acute stroke probably represent an acute phase response. http://repub.eur.nl/res/pub/13020/ 2002-03-01T00:00:00Z http://repub.eur.nl/res/pub/9788/ 2001-01-01T00:00:00Z Cardiovascular risk is increased in GH deficiency (GHD). GHD adults are frequently abdominally obese and display features of the metabolic syndrome. Otherwise healthy abdominally obese subjects have low GH levels and show features of the metabolic syndrome as well. We investigated in healthy nonobese males the effect of the GH receptor antagonist pegvisomant in different metabolic conditions. This is a model for acute GHD without the alterations in body composition associated with GHD. We compared the effect of pegvisomant with that of placebo before and after 3 d of fasting. In addition, we investigated the effect of pegvisomant under normal, i.e. fed, conditions. Three days of fasting as well as pegvisomant alone decreased serum free IGF-I levels (1.0 +/- 0.15 vs. 0.31 +/- 0.05 ng/ml and 0.86 +/- 0.23 vs. 0.46 +/- 0.23 ng/ml, respectively). Fasting in combination with pegvisomant also decreased serum free IGF-I levels (1.0 +/- 0.15 vs. 0.31 +/- 0.07 ng/ml). Treatment with pegvisomant had no additional influence on the decline of free IGF-I induced by fasting. Pegvisomant alone had no influence on insulin sensitivity. The increase in insulin sensitivity induced by fasting was comparable to the increase in insulin sensitivity induced by fasting combined with pegvisomant. Among serum lipid concentrations, only serum triglycerides increased significantly as a result of pegvisomant alone (1.0 +/- 0.2 vs. 1.6 +/- 0.4 mmol/liter). The changes in lipid concentrations induced by fasting alone or pegvisomant were not different from those induced by pegvisomant alone. von Willebrand factor antigen levels declined significantly under the influence of pegvisomant alone (1.1 +/- 0.07 vs. 0.8 +/- 0.06 U/ml). In conclusion, in different metabolic conditions the GH receptor antagonist pegvisomant induces no significant acute changes in the major risk markers for cardiovascular disease. These data suggest that the secondary metabolic changes, e.g. abdominal obesity or inflammatory factors, that develop as a result of long-standing GHD are of primary importance in the pathogenesis of atherosclerosis in patients with GHD.