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E M De Wee,
K Klaij, H C J Eikenboom,
J G Van Der Bom,
K Fijnvandraat,
B A P Laros-Van Gorkom,
E P Mauser-Bunschoten,
K Meijer,
G Goverde,
P W G Van Der Linden,
D C Rijken,
F W G Leebeek
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ABSTRACT: 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.
Haemophilia 09/2011; 18(3):444-51. · 2.60 Impact Factor
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ABSTRACT: Microparticles (MPs) carrying active tissue factor (TF) have been detected in the plasma of cancer patients in particular in those presenting with acute deep vein thrombosis (DVT) or pulmonary embolism (PE). Experimental studies in mice have revealed that circulating MPs carrying TF contribute to thrombus formation.
To study whether unselected patients with an acute confirmed PE have elevated TF activity in the MP fraction (MP-TF activity).
Plasma MP-TF activity was measured in 159 non-selected patients with clinically suspected PE and in 48 healthy controls as previously described. Blood was collected at time of inclusion. The diagnosis of acute PE was confirmed in 54 patients and excluded in 105 patients.
Median MP-TF activity in 159 patients with clinically suspected PE was 72 fM Xa/min [range 32-6657] fM Xa/min and higher than in healthy controls (66 [range 28-183] fM Xa/min; P<0.05). There was no significant difference (P=0.169) in MP-TF activity between patients with confirmed PE (median 84.5 fM Xa/min [range 36-2149]) and patients without PE (72 fM Xa/min [range 32-6657]) fM Xa/min). In the 159 patients with clinically suspected PE we observed in an exploratory analysis higher MP-TF activity levels in patients with active cancer (median 137 fM Xa/min [range 36-6657]) and cardiovascular disease (median 131.5 fM Xa/min [range 45-2149]) than in patients without these disorders (P=0.0004 and P=0.014, respectively).
In patients presenting with clinically suspected PE plasma MP-TF activity was not associated with confirmed PE.
Thrombosis Research 10/2010; 126(4):345-9. · 2.44 Impact Factor
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Journal of Thrombosis and Haemostasis 04/2010; 8(4):853-6. · 5.73 Impact Factor
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ABSTRACT: 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.
British Journal of Haematology 01/2008; 140(2):218-22. · 4.94 Impact Factor
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ABSTRACT: Elevated levels of factor (F)VIII are associated with an increased risk of thrombosis. FVIII levels are determined mainly by von Willebrand factor (VWF). We have investigated the contribution of secretion and clearance rates to the elevated VWF antigen (VWF:Ag) and to the risk of thrombosis. VWF is secreted in equimolar amounts with its propeptide, which has a shorter half-life. VWF propeptide can be used as a measure of VWF secretion and allows estimation of the VWF half-life.
We have measured VWF propeptide, VWF:Ag, FVIII:Ag and FVIII activity (FVIII:C) in the Leiden Thrombophilia Study. In controls, high VWF propeptide was associated with high VWF:Ag, FVIII:Ag and FVIII:C. In contrast to mature VWF:Ag, VWF propeptide was not influenced by blood groups. Using an ELISA-based assay we have shown that VWF propeptide lacks ABO antigens. Levels were higher in men and increased with age. A long VWF half-life was also associated with high VWF:Ag, FVIII:Ag and FVIII:C. The VWF half-life was influenced by blood group (10 h in O vs. 12 h in non-O individuals), but not by sex, and only slightly by age. VWF propeptide was higher in thrombosis patients than in controls. The VWF half-life was similar in patients and controls (11.4 and 11.1 h, respectively).
Both secretion and clearance rates are important determinants of VWF and FVIII levels. However, mainly high VWF and FVIII levels caused by increased secretion seem to be associated with thrombosis. ABO blood group influences the clearance rates of VWF rather than VWF secretion rates.
Journal of Thrombosis and Haemostasis 01/2007; 4(12):2556-62. · 5.73 Impact Factor
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ABSTRACT: To determine the safety, efficacy and user-friendliness of two different postoperative autologous blood re-infusion systems, an open, randomized, controlled study was performed. Eligible consecutive primary and revision total hip and knee replacement patients were randomized for one of the two systems or for a control group in which shed blood was not re-infused. The nursing staff scored user-friendliness. Patients were monitored after re-infusion. In all three patient groups, a restrictive transfusion trigger was used. Sixty-nine of 70 randomized patients were evaluated. Ease of use, efficacy and safety of both re-infusion systems were comparable. There was no difference in allogeneic blood use between the groups. Thirty per cent of the patients re-infused with autologous blood developed a mainly mild, febrile transfusion reaction. No other adverse reactions were seen. Signs of coagulopathy after re-infusion were not found. In multivariate analysis, autologous re-infusion was an independent factor associated with a shorter hospital stay. Both postoperative autologous blood re-infusion systems were of equal efficacy and safety. The contribution of autologous wound blood re-infusion to reduce allogeneic transfusions must be investigated in a larger study.
Transfusion Medicine 11/2006; 16(5):321-8. · 1.14 Impact Factor
