Publications by authors named "Thomas Siegemund"
Article Synopsis
- The study investigates how well the diluted Russel's Viper Venom Time (dRVVT) tests can detect leftover activity from direct oral anticoagulants (DOAC) in patients, aiming to find an efficient screening method for this purpose.
- A total of 80 patients received one of four DOAC medications, and their blood was tested at various times to measure dRVVT alongside DOAC plasma levels.
- Results show that while dRVVT is very effective at indicating significant levels of DOAC, especially with the LA2 assay, it can help in emergency settings to quickly assess anticoagulant effects and make treatment decisions.
Introduction: Recombinant porcine factor VIII (rpFVIII) is a treatment option for break-through bleeds in patients with congenital haemophilia A with inhibitors (CHAwI) on emicizumab. However, there are limited data about the measurement of rpFVIII in the presence of emicizumab.
Aim: To analyse whether rpFVIII can be measured with a chromogenic assay with bovine component (bCSA) in plasma from CHAwI on emicizumab treatment.
Haemophilia A (HA) and B (HB) are X-linked hereditary bleeding disorders caused by lack of activity of coagulation factors VIII (FVIII) or IX (FIX), respectively. Besides conventional products, modern replacement therapies include FVIII or FIX concentrates with an extended half-life (EHL-FVIII/FIX). Two main strategies for measuring plasma FVIII or FIX activity are applied: the one-stage clotting assay (OSCA) and the chromogenic substrate assay (CSA), both calibrated against plasma (FVIII/FIX) standards.
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- * It included plasma samples from 703 patients on rivaroxaban and 252 on apixaban, revealing significant correlations between DOAC levels and TG parameters, except for lag time with apixaban.
- * The findings indicate that rivaroxaban has a stronger impact on TG compared to apixaban, particularly at higher plasma levels, with over 85% accuracy in predicting low DOAC levels based on normal TG parameters.
Article Synopsis
- The study evaluated how direct oral anticoagulants (DOACs) affect thrombin generation (TG) in blood, focusing on their plasma levels in newly anticoagulated patients.
- It included 80 patients, monitoring TG and plasma levels of different DOACs (apixaban, edoxaban, rivaroxaban, and dabigatran) over time.
- Results showed that while all DOACs prolonged certain TG parameters, the effects were influenced by patient-specific baseline levels, suggesting that TG tests might provide a better measure of anticoagulation intensity than just measuring drug levels in plasma.
Article Synopsis
- The study investigates the relationship between the plasma levels of direct oral anticoagulants (DOACs) and thrombin generation (TG) parameters, which offers a more comprehensive understanding of a patient's coagulation status despite variability in drug levels.
- A total of 380 blood samples were analyzed from patients taking different DOACs, and results indicated significant correlations between DOAC drug levels and certain TG parameters, especially for anti-Xa DOACs like apixaban, edoxaban, and rivaroxaban.
- The findings suggest that TG parameters, particularly peak thrombin and velocity index, can be useful in assessing the anticoagulant effects of anti-Xa DOACs, while for
Article Synopsis
- The study investigates the residual effects of direct oral anticoagulants (DOACs) on thrombin generation 12 hours post-intake, which is crucial during emergencies like bleeding or surgery.
- Four types of DOACs (apixaban, edoxaban, rivaroxaban, and dabigatran) were tested on 80 patients, comparing their blood samples before and after medication, and against a control group of blood donors.
- Results showed that all DOACs significantly decreased thrombin generation parameters and prolonged lag time compared to baseline and the healthy control, indicating ongoing antithrombotic activity that may impact clinical decisions in urgent situations.
The present study was performed on whole-mount preparations to investigate the chemical neuroanatomy of the equine myenteric plexus throughout its distribution in the intestinal wall. The objective was to quantify neurons of the myenteric plexus, especially the predominant cholinergic and nitrergic subpopulations. Furthermore, we investigated the distribution of vasoactive intestinal polypeptide and the calcium-binding protein calretinin.
View Article and Find Full Text PDFIn this study we investigated the influence of the presence of the factor V HR2 haplotype, defined by the factor V gene mutation H1299R (FV(HR2)), on thrombin generation. Measurements were performed in platelet-poor plasma of individuals with factor V(HR2) or factor V(Leiden) in comparison to a control group carrying none of these mutations. Coagulation was triggered by low concentrations of recombinant tissue factor in the presence of activated protein C.
View Article and Find Full Text PDFDecrease in thrombin generation is the key effect in anticoagulation. The aim of the present study was to investigate the effect of anticoagulants on thrombin generation and the relation to platelet count. Plasma samples from 10 healthy volunteers (mean age 43.
View Article and Find Full Text PDFHigh plasma concentrations of factor VIII, factor IX and factor XI have been reported as thrombosis risk factors. Using the thrombin generation test in platelet-poor plasma, it was aimed to describe the mechanism for this increased thrombosis risk. Endogenous thrombin potential was measured in platelet-poor plasma in 180 patients with a history of thromboembolism, and results were compared with those of 180 age-matched and sex-matched controls.
View Article and Find Full Text PDFThrombin generation was investigated in platelet-rich plasma (PRP) from 11 healthy controls, 17 patients with severe haemophilia A and 7 patients with severe haemophilia B. Mean endogenous thrombin potential (ETP) in arbitrary fluorescence units (FU) was 226.9 +/- 44.
View Article and Find Full Text PDFPlasma factor II levels in carriers of the 20210A prothrombin variant.
Blood Coagul Fibrinolysis
July 2003