Blood coagulation & fibrinolysis : an international journal in haemostasis and thrombosis
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Blood Coagul. Fibrinolysis · Jan 2007
Epsilon-aminocaproic acid inhibition of fibrinolysis in vitro: should the 'therapeutic' concentration be reconsidered?
The therapeutic concentration of epsilon-aminocaproic acid (EACA) has been 130 microg/ml or greater for nearly 50 years. We tested the effects on clot growth/disintegration of EACA with a plasmatic model of hyperfibrinolysis in vitro. Human plasma was exposed to 1000 U/ml tissue-type plasminogen activator containing 0, 13, 65 or 130 microg/ml EACA, with clot growth/disintegration kinetics quantified via thrombelastography. ⋯ Samples with 130 microg/ml EACA had no sign of lysis present for 30 min. Subtherapeutic to therapeutic concentrations of EACA significantly attenuated or abolished fibrinolysis in the presence of a concentration of tissue-type plasminogen activator more than 2000-fold that encountered systemically during cardiopulmonary bypass. Further clinical investigation is warranted to determine whether smaller concentrations of EACA could provide a reduction in bleeding with a concomitant decrease in thrombotic complications.
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Blood Coagul. Fibrinolysis · Jan 2007
Research for bleeding tendency in patients presenting with significant epistaxis.
To evaluate the association of inherited coagulopathies and acquired conditions (e.g. hypertension, aspirin use) with emergency department admission due to epistaxis. Patients admitted to the emergency department with epistaxis were included. A questionnaire for personal and family history of any bleeding disorder was used. ⋯ Thirteen (68%) patients had hypertensive values on admission. Aspirin use and hypertension were the leading causes of emergency service admission in adults due to epistaxis in this study, although the number of the patients was relatively low. Regarding the low prevalence of inherited coagulopathies, detailed coagulation tests should be reserved for adult patients with positive personal and/or family history of bleeding.
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Blood Coagul. Fibrinolysis · Jan 2007
Hydroxyethyl starch enhances argatroban-mediated decreases in clot propagation and strength by diminishing thrombin-fibrinogen interactions.
Direct thrombin inhibitors (DTIs) have been administered for anticoagulation during cardiopulmonary bypass for patients with heparin-induced thrombocytopenia. While DTIs prolonged clot initiation and decreased clot propagation, clot strength did not change. Hydroxyethyl starches (HES), however, significantly decreased clot propagation and strength. ⋯ Addition of alpha-thrombin/fibrinogen restored clot strength. DTI/HES administration diminished hemostasis to a greater extent than DTI exposure alone. Further investigation is warranted to determine whether this therapeutic approach can improve the safety of anticoagulation during cardiopulmonary bypass in patients with heparin-induced thrombocytopenia.
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Blood Coagul. Fibrinolysis · Jan 2007
In-vitro efficacy of different platelet glycoprotein IIb/IIIa antagonists and thrombolytics on platelet/fibrin-mediated clot dynamics in human whole blood using thrombelastography.
Suppressing platelet activation improves efficacy of thrombolytic therapy for stroke and acute myocardial infarction. Combination treatment with recombinant tissue plasminogen activator (r-tPA) and glycoprotein IIb/IIIa (GPIIb/IIIa) inhibitor that binds with high affinity to platelets may therefore improve the efficacy of thrombolytic therapy. ⋯ The combination of the active form of roxifiban (XV459; Class I) or the active form of orbofiban (Class II) with a subeffective concentration of r-tPA resulted in a synergistic effect in clot lysis with roxifiban active form XV459 but not with that of orbofiban at therapeutically achievable concentrations that inhibit human platelet aggregation. These data indicate differential enhanced thrombolysis of low levels of r-tPA with high-affinity Class I but not with low-affinity Class II GPIIb/IIIa antagonists in the absence of anticoagulants.