The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform
Fritz Mertzlufft - One of the best experts on this subject based on the ideXlab platform.
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a quick assay for monitoring recombinant hirudin during cardiopulmonary bypass in patients with heparin induced thrombocytopenia type iiadaptation of the Ecarin clotting time to the act ii device
The Journal of Thoracic and Cardiovascular Surgery, 2000Co-Authors: Reas Koster, Matthias Loebe, Roland Hansen, Mathias Bauer, Fritz MertzlufftAbstract:Abstract Background: Recombinant hirudin is increasingly advocated as a promising alternative anticoagulation for patients with heparin-induced thrombocytopenia type II during cardiopulmonary bypass. This requires monitoring of the Ecarin clotting time. No commercial Ecarin clotting time assay is available for clinical use. We adapted the Ecarin clotting time to the easy-to-handle ACT II device. Methods: Three different concentrations of the Ecarin reagent (20, 10, 5 U/mL) were investigated as preliminary studies. Standard calibration curves were constructed for concentrations of recombinant hirudin ranging from 0 to 5 μg/mL. In vivo samples were collected from patients with heparin-induced thrombocytopenia type II who underwent cardiopulmonary bypass, and the values were compared with the values obtained by the chromogenic method. The final concentration for the assay of 5 IU/mL Ecarin was further assessed in vitro for reproducibility and the influence of variations in hematocrit, platelet count, and procoagulants. Results: All three concentrations of Ecarin revealed linearity to 5 μg/mL concentrations of recombinant hirudin. The Ecarin concentration of 5 U/mL revealed the best correlation (0.87) to the laboratory method, was reproducible over the whole recombinant hirudin range, and was not influenced by the variations in the in vitro setup. Conclusions: The ACT II/Ecarin clotting time with an Ecarin concentration of 5 U/mL is a simple and reliable assay for monitoring recombinant hirudin during cardiopulmonary bypass. Use of this assay allows a wider use of recombinant hirudin in patients with heparin-induced thrombocytopenia type II during bypass and thereby may contribute to the safer management of these patients. (J Thorac Cardiovasc Surg 2000;119:1278-83)
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hirudin monitoring using the tas Ecarin clotting time in patients with heparin induced thrombocytopenia type ii
Journal of Cardiothoracic and Vascular Anesthesia, 2000Co-Authors: Andreas Koster, Roland Hansen, Mathias Bauer, O Grauhan, Harald Hausmann, R Hetzer, Herrmann Kuppe, Fritz MertzlufftAbstract:Abstract Objective: To assess the reliability of the TAS/Ecarin clotting time (ECT) for on-line monitoring of r-hirudin in cardiovascular surgery with and without cardiopulmonary bypass (CPB). Design: Samples were spiked with r-hirudin (0 to 5 μg/mL) and calibration curves constructed. Reproducibility was evaluated by measurement of the sample five times at each concentration. The influence of variations in hematocrit, plasma factors, and platelet count on the test results was examined. Samples were obtained from patients during cardiovascular surgery with CPB (n = 8), without CPB (n = 3), and from volunteers (n = 5) and compared with the laboratory reference tests. All tests were performed in duplicate. Setting: Deutsches Herzzentrum Berlin. Participants: Five healthy volunteers and 11 patients undergoing cardiovascular surgery. Interventions: None. Measurements and Main Results: The TAS/ECT showed linearity and reliability to an r-hirudin concentration of 5 μg/mL and was not influenced (p
Gary W Moore - One of the best experts on this subject based on the ideXlab platform.
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taipan snake venom time coupled with Ecarin time enhances lupus anticoagulant detection in nonanticoagulated patients
Blood Coagulation & Fibrinolysis, 2016Co-Authors: Gary W Moore, Aidan P Culhane, James C Maloney, Robert A Archer, Karen Breen, Beverley J HuntAbstract:A study is presented which assesses the diagnostic impact of incorporating Taipan snake venom time (TSVT) with Ecarin time confirmatory test into an existing dilute Russell's viper venom time (dRVVT) and activated partial thromboplastin time (APTT) repertoire when testing nonanticoagulated patients
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combining taipan snake venom time Ecarin time screening with the mixing studies of conventional assays increases detection rates of lupus anticoagulants in orally anticoagulated patients
Thrombosis Journal, 2007Co-Authors: Gary W MooreAbstract:Background Oral anticoagulation compromises conventional lupus anticoagulant (LA) screening assays. Mixing studies can counteract the oral anticoagulant effect but the dilution reduces sensitivity and can generate false negative results. A firm diagnosis can be made from mixing studies when an elevated screen ratio is accompanied by a confirm ratio that generates significant correction to demonstrate phospholipid dependence, but also returns into the reference range, indicating complete normalisation of the oral anticoagulant effect. Taipan snake venom time (TSVT) with Ecarin time (ET) as a confirmatory test comprises an oral anticoagulant insensitive LA detection system and this study investigates the potential impact on detection rates when coupled with mixing studies on standard assays.
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Combining Taipan snake venom time/Ecarin time screening with the mixing studies of conventional assays increases detection rates of lupus anticoagulants in orally anticoagulated patients
Thrombosis Journal, 2007Co-Authors: Gary W MooreAbstract:Background Oral anticoagulation compromises conventional lupus anticoagulant (LA) screening assays. Mixing studies can counteract the oral anticoagulant effect but the dilution reduces sensitivity and can generate false negative results. A firm diagnosis can be made from mixing studies when an elevated screen ratio is accompanied by a confirm ratio that generates significant correction to demonstrate phospholipid dependence, but also returns into the reference range, indicating complete normalisation of the oral anticoagulant effect. Taipan snake venom time (TSVT) with Ecarin time (ET) as a confirmatory test comprises an oral anticoagulant insensitive LA detection system and this study investigates the potential impact on detection rates when coupled with mixing studies on standard assays.
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Alteration in the laboratory profile of a lupus anticoagulant in a patient with non‐Hodgkin's lymphoma
Clinical and Laboratory Haematology, 2004Co-Authors: Gary W Moore, A Kamat, D A Gurney, O O'connor, Savita Rangarajan, Robert Carr, Geoffrey F. SavidgeAbstract:Summary We describe a patient with non-Hodgkin's lymphoma who developed a lupus anticoagulant (LA) detectable by activated partial thromboplastin time (APTT), dilute Russell's viper venom time (DRVVT) and kaolin clotting time (KCT). IgM anticardiolipin antibodies (ACA) were elevated. At a later admission, and following treatment for the lymphoma, routine coagulation screening showed an elevated prothrombin time (PT) without correction in mixing tests using a recombinant thromboplastin. Routine APTT was below the reference range and ACA levels were normal. Raw data for one-stage factor assays demonstrated the presence of an inhibitor. Analysis for LA was undertaken by DRVVT, KCT, activated seven lupus anticoagulant assay, Taipan snake venom time, platelet neutralisation procedures (PNP), Ecarin time and PT using rabbit brain thromboplastin. The results revealed a LA capable of prolonging the clotting times of the PNPs and PT using recombinant thromboplastin, but that was corrected using Ecarin venom, modified PNP and brain thromboplastin. The antibody also demonstrated the lupus anticoagulant co-factor effect. The factor VIII : C was markedly raised which may have masked the LA in the APTT. The changing laboratory profile over time demonstrates the effects of LA heterogeneity and variations in sensitivity and specificity of assays for the detection of antiphospholipid antibodies.
John W. Eikelboom - One of the best experts on this subject based on the ideXlab platform.
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comparison of the Ecarin chromogenic assay and diluted thrombin time for quantification of dabigatran concentrations
Journal of Thrombosis and Haemostasis, 2017Co-Authors: Iqbal H Jaffer, John W. Eikelboom, Noel C Chan, Robin S Roberts, James C Fredenburgh, Jeffrey I WeitzAbstract:Essentials Routine monitoring is unnecessary but measuring dabigatran levels is helpful in certain situations. We compared Ecarin chromogenic assay (STA-ECA-II) and dilute thrombin time (dTT) in patient samples. Both tests provided accurate measurements over a wide range of dabigatran concentrations. Adoption of STA-ECA-II and dTT into routine clinical practice will improve patient care. SummaryBackground Although routine coagulation monitoring is unnecessary, measuring plasma dabigatran concentrations can be useful for detecting drug accumulation in renal failure or overdose, assessing the contribution of dabigatran to serious bleeding, planning the timing of urgent surgery or intervention, or determining the suitability for thrombolytic therapy for acute ischemic stroke. Dabigatran concentrations can be quantified using chromogenic or clot-based tests, such as the Ecarin chromogenic assay (ECA) and the diluted thrombin time (dTT), respectively. Objective The purpose of this study was to compare the results of these assays with dabigatran concentrations measured by the reference standard of mass spectrometry in samples from 50 dabigatran-treated patients collected at peak and trough after at least 4 months of drug intake. Methods Drug levels measured with either the STA Ecarin Chromogenic Assay-II (STA-ECA-II) or dTT were linearly correlated with those determined by mass spectrometry over a wide range of concentrations. Results and Conclusions For detection of levels below 50 ng mL−1 both tests have specificities of at least 96%, suggesting that they accurately detect even low levels of drug. Therefore, regardless of whether a chromogenic or clot-based platform is preferred, the STA-ECA-II and dTT are useful tests for measuring dabigatran concentrations. Unfortunately, neither test is licensed by the United States Food and Drug Administration. Although approved in other jurisdictions, the dTT and STA-ECA-II are not widely or rapidly available in most hospitals. Therefore, cooperation between regulators and hospitals is urgently needed to render these tests readily available to inform patient care.
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Idarucizumab for Dabigatran Reversal — Full Cohort Analysis
The New England Journal of Medicine, 2017Co-Authors: Charles V. Pollack, Paul A. Reilly, John W. Eikelboom, Stephan Glund, Richard A. Bernstein, Robert Dubiel, Menno V. Huisman, Elaine M. HylekAbstract:BackgroundIdarucizumab, a monoclonal antibody fragment, was developed to reverse the anticoagulant effect of dabigatran. MethodsWe performed a multicenter, prospective, open-label study to determine whether 5 g of intravenous idarucizumab would be able to reverse the anticoagulant effect of dabigatran in patients who had uncontrolled bleeding (group A) or were about to undergo an urgent procedure (group B). The primary end point was the maximum percentage reversal of the anticoagulant effect of dabigatran within 4 hours after the administration of idarucizumab, on the basis of the diluted thrombin time or Ecarin clotting time. Secondary end points included the restoration of hemostasis and safety measures. ResultsA total of 503 patients were enrolled: 301 in group A, and 202 in group B. The median maximum percentage reversal of dabigatran was 100% (95% confidence interval, 100 to 100), on the basis of either the diluted thrombin time or the Ecarin clotting time. In group A, 137 patients (45.5%) presented ...
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Idarucizumab for Dabigatran Reversal — Full Cohort Analysis
New England Journal of Medicine, 2017Co-Authors: Charles V. Pollack, Paul A. Reilly, Joanne Van Ryn, John W. Eikelboom, Stephan Glund, Richard A. Bernstein, Robert Dubiel, Menno V. Huisman, Elaine M. Hylek, Chak-wah KamAbstract:© 2017 Massachusetts Medical Society. BACKGROUND Idarucizumab, a monoclonal antibody fragment, was developed to reverse the anticoagulant effect of dabigatran. METHODS We performed a multicenter, prospective, open-label study to determine whether 5 g of intravenous idarucizumab would be able to reverse the anticoagulant effect of dabigatran in patients who had uncontrolled bleeding (group A) or were about to undergo an urgent procedure (group B). The primary end point was the maximum percentage reversal of the anticoagulant effect of dabigatran within 4 hours after the administration of idarucizumab, on the basis of the diluted thrombin time or Ecarin clotting time. Secondary end points included the restoration of hemostasis and safety measures. RESULTS A total of 503 patients were enrolled: 301 in group A, and 202 in group B. The median maximum percentage reversal of dabigatran was 100% (95% confidence interval, 100 to 100), on the basis of either the diluted thrombin time or the Ecarin clotting time. In group A, 137 patients (45.5%) presented with gastrointestinal bleeding and 98 (32.6%) presented with intracranial hemorrhage; among the patients who could be assessed, the median time to the cessation of bleeding was 2.5 hours. In group B, the median time to the initiation of the intended procedure was 1.6 hours; periprocedural hemostasis was assessed as normal in 93.4% of the patients, mildly abnormal in 5.1%, and moderately abnormal in 1.5%. At 90 days, thrombotic events had occurred in 6.3% of the patients in group A and in 7.4% in group B, and the mortality rate was 18.8% and 18.9%, respectively. There were no serious adverse safety signals. CONCLUSIONS In emergency situations, idarucizumab rapidly, durably, and safely reversed the anticoagulant effect of dabigatran.
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Laboratory measurement of the direct oral anticoagulants
British Journal of Haematology, 2015Co-Authors: Brian Dale, Noel C Chan, John W. EikelboomAbstract:Summary Direct oral anticoagulants (DOACs), including the direct thrombin inhibitor, dabigatran, and the direct factor Xa (FXa) inhibitors, rivaroxaban, apixaban and edoxaban, are approved for thromboembolism prevention and treatment. These drugs do not require routine coagulation monitoring but, in some circumstances, measurement of drug level or anticoagulant effect may be necessary. Although traditional coagulation tests lack analytical sensitivity and specificity, they are widely available and inexpensive, and can provide useful information regarding the residual anticoagulant effect of DOACs. Hemoclot® and Ecarin-based assays can be used to quantify dabigatran level and calibrated chromogenic anti-FXa assays are suitable for measuring rivaroxaban, apixaban and edoxaban levels, but these tests are not yet widely available.
Reas Koster - One of the best experts on this subject based on the ideXlab platform.
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a quick assay for monitoring recombinant hirudin during cardiopulmonary bypass in patients with heparin induced thrombocytopenia type iiadaptation of the Ecarin clotting time to the act ii device
The Journal of Thoracic and Cardiovascular Surgery, 2000Co-Authors: Reas Koster, Matthias Loebe, Roland Hansen, Mathias Bauer, Fritz MertzlufftAbstract:Abstract Background: Recombinant hirudin is increasingly advocated as a promising alternative anticoagulation for patients with heparin-induced thrombocytopenia type II during cardiopulmonary bypass. This requires monitoring of the Ecarin clotting time. No commercial Ecarin clotting time assay is available for clinical use. We adapted the Ecarin clotting time to the easy-to-handle ACT II device. Methods: Three different concentrations of the Ecarin reagent (20, 10, 5 U/mL) were investigated as preliminary studies. Standard calibration curves were constructed for concentrations of recombinant hirudin ranging from 0 to 5 μg/mL. In vivo samples were collected from patients with heparin-induced thrombocytopenia type II who underwent cardiopulmonary bypass, and the values were compared with the values obtained by the chromogenic method. The final concentration for the assay of 5 IU/mL Ecarin was further assessed in vitro for reproducibility and the influence of variations in hematocrit, platelet count, and procoagulants. Results: All three concentrations of Ecarin revealed linearity to 5 μg/mL concentrations of recombinant hirudin. The Ecarin concentration of 5 U/mL revealed the best correlation (0.87) to the laboratory method, was reproducible over the whole recombinant hirudin range, and was not influenced by the variations in the in vitro setup. Conclusions: The ACT II/Ecarin clotting time with an Ecarin concentration of 5 U/mL is a simple and reliable assay for monitoring recombinant hirudin during cardiopulmonary bypass. Use of this assay allows a wider use of recombinant hirudin in patients with heparin-induced thrombocytopenia type II during bypass and thereby may contribute to the safer management of these patients. (J Thorac Cardiovasc Surg 2000;119:1278-83)
Mathias Bauer - One of the best experts on this subject based on the ideXlab platform.
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a quick assay for monitoring recombinant hirudin during cardiopulmonary bypass in patients with heparin induced thrombocytopenia type iiadaptation of the Ecarin clotting time to the act ii device
The Journal of Thoracic and Cardiovascular Surgery, 2000Co-Authors: Reas Koster, Matthias Loebe, Roland Hansen, Mathias Bauer, Fritz MertzlufftAbstract:Abstract Background: Recombinant hirudin is increasingly advocated as a promising alternative anticoagulation for patients with heparin-induced thrombocytopenia type II during cardiopulmonary bypass. This requires monitoring of the Ecarin clotting time. No commercial Ecarin clotting time assay is available for clinical use. We adapted the Ecarin clotting time to the easy-to-handle ACT II device. Methods: Three different concentrations of the Ecarin reagent (20, 10, 5 U/mL) were investigated as preliminary studies. Standard calibration curves were constructed for concentrations of recombinant hirudin ranging from 0 to 5 μg/mL. In vivo samples were collected from patients with heparin-induced thrombocytopenia type II who underwent cardiopulmonary bypass, and the values were compared with the values obtained by the chromogenic method. The final concentration for the assay of 5 IU/mL Ecarin was further assessed in vitro for reproducibility and the influence of variations in hematocrit, platelet count, and procoagulants. Results: All three concentrations of Ecarin revealed linearity to 5 μg/mL concentrations of recombinant hirudin. The Ecarin concentration of 5 U/mL revealed the best correlation (0.87) to the laboratory method, was reproducible over the whole recombinant hirudin range, and was not influenced by the variations in the in vitro setup. Conclusions: The ACT II/Ecarin clotting time with an Ecarin concentration of 5 U/mL is a simple and reliable assay for monitoring recombinant hirudin during cardiopulmonary bypass. Use of this assay allows a wider use of recombinant hirudin in patients with heparin-induced thrombocytopenia type II during bypass and thereby may contribute to the safer management of these patients. (J Thorac Cardiovasc Surg 2000;119:1278-83)
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hirudin monitoring using the tas Ecarin clotting time in patients with heparin induced thrombocytopenia type ii
Journal of Cardiothoracic and Vascular Anesthesia, 2000Co-Authors: Andreas Koster, Roland Hansen, Mathias Bauer, O Grauhan, Harald Hausmann, R Hetzer, Herrmann Kuppe, Fritz MertzlufftAbstract:Abstract Objective: To assess the reliability of the TAS/Ecarin clotting time (ECT) for on-line monitoring of r-hirudin in cardiovascular surgery with and without cardiopulmonary bypass (CPB). Design: Samples were spiked with r-hirudin (0 to 5 μg/mL) and calibration curves constructed. Reproducibility was evaluated by measurement of the sample five times at each concentration. The influence of variations in hematocrit, plasma factors, and platelet count on the test results was examined. Samples were obtained from patients during cardiovascular surgery with CPB (n = 8), without CPB (n = 3), and from volunteers (n = 5) and compared with the laboratory reference tests. All tests were performed in duplicate. Setting: Deutsches Herzzentrum Berlin. Participants: Five healthy volunteers and 11 patients undergoing cardiovascular surgery. Interventions: None. Measurements and Main Results: The TAS/ECT showed linearity and reliability to an r-hirudin concentration of 5 μg/mL and was not influenced (p