26 resultados para Prothrombin


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BACKGROUND: It has been suggested that changes in blood coagulation and fibrinolysis might explain the observed association between depression and coronary artery disease (CAD). So far, only a few coagulation factors have been investigated in this regard, and the results were not consistent. DESIGN: The aim of our study was to analyse a broad range of coagulation and fibrinolytic factors, with emphasis on factors directly involved in clot formation and degradation or reflecting coagulation activation, in patients with CAD and controls without CAD, as assessed by coronary angiography, who also underwent a diagnostic procedure for depression. METHODS: We screened 306 patients with CAD and controls without CAD for depression using the Hospital Anxiety and Depression Scale and Allgemeine Depressions Skala-L questionnaires. In participants with positive screening result, diagnosis of major depression was confirmed or excluded by a structured interview. We analysed the following coagulation and fibrinolytic factors: fibrinogen, prothrombin fragment F1+2, factor XIII A-subunit, factor XIII B-subunit, tissue plasminogen activator, plasminogen activator inhibitor-1, thrombin-activable fibrinolysis inhibitor, and D-dimer. RESULTS: We did not observe significant associations between depression and CAD, nor between depression and cardiovascular risk factors. Coagulation and fibrinolytic factors showed no differences between patients with CAD and controls, but they were associated with several cardiovascular risk factors. Depression was not associated with coagulation and fibrinolytic factors. No associations were found either when both CAD and depression were taken into account. CONCLUSION: Our study gives no evidence that there is a significant relation among depression, CAD, and blood coagulation and fibrinolysis.

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OBJECTIVE: Numerous studies have reported the technical aspects and results of surgical and/or endovascular treatment of cranial dural arteriovenous fistulae (cDAVF) and spinal dural arteriovenous fistulae (sDAVF). Only a few of them have addressed the question of thrombophilic conditions, which may be relevant as pathogenetic factors or can increase the risk for venous thromboembolic events. Therefore, the objective of this study is to compare thrombophilic risk factors in patients with cDAVF and sDAVF with no history of trauma. METHODS: A total of 43 patients (25 with cDAVF and 18 with sDAVF) were included in this study. Blood samples were analyzed for G20210A mutation of the prothrombin gene and factor V Leiden mutation. In all patients, prothrombin time, international normalized ratio, fibrinogen, antithrombin, protein C and S activity, von Willebrand factor antigen, ristocetin cofactor activity, D-dimer, coagulation factor VIII activity, and tissue factor pathway inhibitor were determined. Screening was performed for the occurrence of lupus antiphospholipid and cardiolipin antibodies. RESULTS: The prevalence of G20210A mutation of the prothrombin gene was significantly higher in patients with cDAVF (n = 6) compared with patients with sDAVF (n = 0; P < 0.05, Fisher's exact test). A factor V Leiden mutation was found in 3 patients with sDAVF and in 1 patient with cDAVF (P = 0.29, Fisher's exact test). No significant difference was found for other parameters, except for fibrinogen, but decreased protein C activity was more frequent in patients with cDAVF compared with patients with sDAVF (4 versus 1). Decreased protein S activity was encountered in 3 patients (2 with sDAVF and 1 with cDAVF). Cardiolipin antibodies were found in 2 patients with cDAVF but in none with sDAVF, whereas only 1 patient with sDAVF had lupus antiphospholipid antibodies. CONCLUSION: In both groups of patients with dural arteriovenous fistulae, genetic thrombophilic abnormalities occurred in a higher percentage than in the general population. The differences of the genetic abnormalities may be involved in different pathophysiological mechanism(s) in the development of these distinct neurovascular entities.

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Blood coagulation activation might be one mechanism linking acute mental stress with coronary events. We investigated the natural habituation of coagulation responses and recovery to short-term mental stress. Three times with one-week intervals, 24 men (mean age 47 +/- 7 years) underwent the same 13-min stressor (preparation, job interview, mental arithmetic). During each visit venous blood was obtained four times (baseline, immediately post-stress, 45 min of recovery, 105 min of recovery). Eight blood coagulation parameters were measured at weeks one and three. Acute stress provoked increases in von Willebrand factor antigen, fibrinogen, clotting factor FVII activity (FVII:C), FVIII:C, FXII:C (p's < or = 0.019), and D-dimer (N.S.). All coagulation parameters experienced full recovery except FVIII:C (p = 0.022). Stress did not significantly affect activated partial thromboplastin time and prothrombin time. At all time points FVIII:C and FXII:C levels were significantly higher at week one compared to week three (p's < or = 0.041). Before catheter insertion, systolic blood pressure (p = 0.001) and heart rate (p = 0.026) were relatively higher at week one. Unlike the magnitude of systolic blood pressure response to stress (p = 0.007) and of cortisol recovery from stress (p = 0.002), the magnitude of all coagulation responses to stress and the recovery from stress were similar in week one and week three. Sympathetic activation with anticipatory stress best explained increased baseline activity in FVIII and FXII at week one. An incapacity of the coagulation system to adapt to stress repeats is perhaps a consequence of evolution, but might also contribute to increased coronary risk in some individuals, particularly in those with cardiovascular diseases.

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INTRODUCTION: Acute psychosocial stress accelerates blood coagulation and elicits hemoconcentration which mechanisms are implicated in acute coronary thrombotic events. We investigated the extent to which the change in prothrombotic measures with acute stress reflects hemoconcentration and genuine activation of coagulation. MATERIAL AND METHODS: Twenty-one middle-aged healthy men underwent three sessions of a combined speech and mental arithmetic task with one-week intervals. Coagulation and plasma volume were assessed at baseline, immediately post-stress, and 45 min post-stress at sessions one and three. Measures of both visits were aggregated to enhance robustness of individual biological stress responses. Changes in eight coagulation measures with and without adjustment for simultaneous plasma volume shift were compared. RESULTS: From baseline to immediately post-stress, unadjusted levels of fibrinogen (p=0.028), clotting factor VII activity (FVII:C) (p=0.001), FVIII:C (p<0.001), FXII:C (p<0.001), and von Willebrand factor (VWF) (p=0.008) all increased. Taking into account hemoconcentration, fibrinogen (p=0.020) and FVII:C levels (p=0.001) decreased, activated partial prothrombin time (APPT) shortened (p<0.001) and prothrombin time (PT) was prolonged (p<0.001). Between baseline and 45 min post-stress, unadjusted (p=0.050) and adjusted (p=0.001) FVIII:C levels increased, adjusted APTT was prolonged (p=0.017), and adjusted PT was shortened (p=0.033). D-dimer levels did not significantly change over time. CONCLUSIONS: Adjustment for stress-hemoconcentration altered the course of unadjusted levels of several prothrombotic factors. After adjustment for hemoconcentration, APPT was shortened immediately post-stress, whereas 45 min post-stress, FVIII:C was increased and PT was shortened. Procoagulant changes to acute stress may reflect both hemoconcentration and genuine activation of coagulation molecules and pathways.

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BACKGROUND While the assessment of analytical precision within medical laboratories has received much attention in scientific enquiry, the degree of as well as the sources causing variation between them remains incompletely understood. In this study, we quantified the variance components when performing coagulation tests with identical analytical platforms in different laboratories and computed intraclass correlations coefficients (ICC) for each coagulation test. METHODS Data from eight laboratories measuring fibrinogen twice in twenty healthy subjects with one out of 3 different platforms and single measurements of prothrombin time (PT), and coagulation factors II, V, VII, VIII, IX, X, XI and XIII were analysed. By platform, the variance components of (i) the subjects, (ii) the laboratory and the technician and (iii) the total variance were obtained for fibrinogen as well as (i) and (iii) for the remaining factors using ANOVA. RESULTS The variability for fibrinogen measurements within a laboratory ranged from 0.02 to 0.04, the variability between laboratories ranged from 0.006 to 0.097. The ICC for fibrinogen ranged from 0.37 to 0.66 and from 0.19 to 0.80 for PT between the platforms. For the remaining factors the ICC's ranged from 0.04 (FII) to 0.93 (FVIII). CONCLUSIONS Variance components that could be attributed to technicians or laboratory procedures were substantial, led to disappointingly low intraclass correlation coefficients for several factors and were pronounced for some of the platforms. Our findings call for sustained efforts to raise the level of standardization of structures and procedures involved in the quantification of coagulation factors.

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The new oral anticoagulants (NOACs) represent alternative antithrombotic agents for prophylaxis and therapy of thromboembolic diseases. They act either by inhibition of the clotting factor Xa or IIa (thrombin). As a consequence, they influence several coagulation assays (for example prothrombin time, activated partial thromboplastin time). Because of the short half-life of these new agents, these changes show great variations in the course of 24 hours. Furthermore, there are significant differences of laboratory results depending on the used reagents. We explain the influence of apixaban, rivaroxaban (factor Xa inhibitors) and dabigatran (thrombin inhibitor) on the most commonly used coagulation assays. Besides we show that this influence depends on the way of action of the drug as well as on the principle of the coagulation assay. Being aware of this relationships helps to interpret the results of coagulation assays under influence of NOACs correctly.

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Habituelle Aborte Ein Spontanabort ereignet sich bei etwa 15 % aller klinisch festgestellten Schwangerschaften. Vom betroffenen Paar wird er ausnahmslos als äußerst traumatisch erlebt. Insbesondere gilt dies beim habituellen Abort (≥ 3 Aborte in Folge), der etwa 1 % der Schwangerschaften betrifft. In der Hoffnung, weitere Aborte zu verhindern, werden entsprechend große Anstrengungen unternommen, die jeweilige Ursache zu eruieren. Gerinnungsphysiologische Einflüsse Pathophysiologisch spielen nebst organischen und zytogenetischen Anomalien beim Fetus vermutlich auch gerinnungsphysiologische Einflüsse eine ursächliche Rolle, insbesondere erworbene und hereditäre prokoagulatorische Störungen. Diese können das im Rahmen der Schwangerschaft schon physiologisch erhöhte Gerinnungspotenzial zusätzlich verstärken und damit die Blutversorgung des Fetus potenziell behindern, was mit der Gefahr seiner Abstoßung einhergeht. Thrombophilie Auch wenn der diesbezügliche Beweis im Einzelfall schwierig zu erbringen ist, erscheint eine ungünstige Beeinflussung des Abortrisikos durch erworbene und hereditäre Thrombophilien plausibel. Daraus ergibt sich unschwer die Folgerung oder Hoffnung, dass antiaggregatorische und antikoagulatorische Maßnahmen eine günstige Wirkung haben könnten. Der vorliegende Beitrag geht auf die bekannten sowie teils auch nur vermuteten pathophysiologischen Mechanismen und die sich daraus ergebenden therapeutischen bzw. präventiven Möglichkeiten ein.

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BACKGROUND Dysregulation of the coagulation system due to inflammatory responses and cross-species molecular incompatibilities represents a major obstacle to successful xenotransplantation. We hypothesized that complement inhibition mediated by transgenic expression of human CD46 in pigs might also regulate the coagulation and fibrinolysis cascades and tested this in ex vivo human-to-pig xenoperfusions. METHODS Forelimbs of wild-type and hCD46/HLA-E double transgenic pigs were ex vivo xenoperfused for 12 hours with whole heparinized human blood. Muscle biopsies were stained for galactose-α1,3-galactose, immunoglobulin M, immunoglobulin G, complement, fibrin, tissue factor, fibrinogen-like protein 2, tissue plasminogen activator (tPA), and plasminogen activator inhibitor (PAI)-1. The PAI-1/tPA complexes, D-dimers, and prothrombin fragment F1 + 2 were measured in plasma samples after ex vivo xenoperfusion. RESULTS No differences of galactose expression or deposition of immunoglobulin M and immunoglobulin G were found in xenoperfused tissues of wild type and transgenic limbs. In contrast, significantly lower deposition of C5b-9 (P < 0.0001), fibrin (P = 0.009), and diminished expression of tissue factor (P = 0.005) and fibrinogen-like protein 2 (P = 0.028) were found in xenoperfused tissues of transgenic limbs. Levels of prothrombin fragment F1 + 2 (P = 0.031) and D-dimers (P = 0.044) were significantly lower in plasma samples obtained from transgenic as compared to wild-type pig limb perfusions. The expression of the fibrinolytic marker tPA was significantly higher (P = 0.009), whereas PAI-1 expression (P = 0.022) and PAI-1/tPA complexes in plasma (P = 0.015) were lower after transgenic xenoperfusion as compared to wild-type xenoperfusions. CONCLUSIONS In this human-to-pig xenoperfusion model, complement inhibition by transgenic hCD46 expression led to a significant inhibition of procoagulant and antifibrinolytic pathways.

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BACKGROUND Whether screening for thrombophilia is useful for patients after a first episode of venous thromboembolism (VTE) is a controversial issue. However, the impact of thrombophilia on the risk of recurrence may vary depending on the patient's age at the time of the first VTE. PATIENTS AND METHODS Of 1221 VTE patients (42 % males) registered in the MAISTHRO (MAin-ISar-THROmbosis) registry, 261 experienced VTE recurrence during a 5-year follow-up after the discontinuation of anticoagulant therapy. RESULTS Thrombophilia was more common among patients with VTE recurrence than those without (58.6 % vs. 50.3 %; p = 0.017). Stratifying patients by the age at the time of their initial VTE, Cox proportional hazards analyses adjusted for age, sex and the presence or absence of established risk factors revealed a heterozygous prothrombin (PT) G20210A mutation (hazard ratio (HR) 2.65; 95 %-confidence interval (CI) 1.71 - 4.12; p < 0.001), homozygosity/double heterozygosity for the factor V Leiden and/or PT mutation (HR 2.35; 95 %-CI 1.09 - 5.07, p = 0.030), and an antithrombin deficiency (HR 2.12; 95 %-CI 1.12 - 4.10; p = 0.021) to predict recurrent VTE in patients aged 40 years or older, whereas lupus anticoagulants (HR 3.05; 95%-CI 1.40 - 6.66; p = 0.005) increased the risk of recurrence in younger patients. Subgroup analyses revealed an increased risk of recurrence for a heterozygous factor V Leiden mutation only in young females without hormonal treatment whereas the predictive value of a heterozygous PT mutation was restricted to males over the age of 40 years. CONCLUSIONS Our data do not support a preference of younger patients for thrombophilia testing after a first venous thromboembolic event.

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Chemerin is a well-established modulator of immune cell function and its serum levels are induced in inflammatory diseases. Liver cirrhosis is associated with inflammation which is aggravated by portal hypertension. The objective of this study was to evaluate whether chemerin is induced in patients with more severe liver cirrhosis and portal hypertension. Chemerin has been measured by ELISA in the portal venous serum (PVS), systemic venous serum (SVS) and hepatic venous serum (HVS) of 45 patients with liver cirrhosis. Chemerin is higher in HVS compared to PVS in accordance with our recently published finding. SVS, HVS and PVS chemerin decline in patients with more advanced liver injury defined by the CHILD-PUGH score. Hepatic chemerin has been determined in a small cohort and is similarly expressed in normal and cirrhotic liver. MELD score and serum markers of liver and kidney function do not correlate with chemerin. There is a positive correlation of chemerin in all compartments with Quick prothrombin time and of SVS chemerin with systolic blood pressure. PVS chemerin is induced in patients with modest/massive ascites but this does not translate into higher HVS and SVS levels. Chemerin is not associated with variceal size. Reduction of portal pressure by transjugular intrahepatic portosystemic shunt does not affect chemerin levels. These data show that low chemerin in patients with more severe liver cirrhosis is associated with reduced Quick prothrombin time.

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OBJECTIVE To evaluate horses with atrial fibrillation for hypercoagulability; plasma D-dimer concentrations, as a marker of a procoagulant state; and a relationship between coagulation profile results and duration of atrial fibrillation or presence of structural heart disease. DESIGN Case-control study. ANIMALS Plasma samples from 42 horses (25 with atrial fibrillation and 17 without cardiovascular or systemic disease [control group]). PROCEDURES Results of hematologic tests (ie, plasma fibrinogen and D-dimer concentrations, prothrombin and activated partial thromboplastin times, and antithrombin activity) in horses were recorded to assess coagulation and fibrinolysis. Historical and clinical variables, as associated with a hypercoagulable state in other species, were also recorded. RESULTS Horses with atrial fibrillation and control horses lacked clinical signs of hypercoagulation or thromboembolism. Compared with control horses, horses with atrial fibrillation had significantly lower antithrombin activity. No significant differences in plasma fibrinogen and D-dimer concentrations and prothrombin and activated partial thromboplastin times existed between horse groups. In horses with atrial fibrillation versus control horses, a significantly larger proportion had an abnormal plasma D-dimer concentration (10/25 vs 2/17), test results indicative of subclinical activated coagulation (18/25 vs 6/17), or abnormal coagulation test results (25/121 vs 7/85), respectively. CONCLUSIONS AND CLINICAL RELEVANCE Horses with atrial fibrillation did not have clinical evidence of a hypercoagulable state, but a higher proportion of horses with atrial fibrillation, compared with control horses, did have subclinical activated coagulation on the basis of standard coagulation test results.