Hamostaseologie
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Most hospitalized patients present risk factors for venous thromboembolism (VTE). Deep vein thrombosis and pulmonary embolism are relevant causes for morbidity and mortality in the perihospital phase, with a possibly fatal outcome. ⋯ Definition of different risk categories and treatment of patients according to the individual risk profile is standard in VTE prophylaxis. For VTE prophylaxis various medical and mechanical options are available.
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The prognosis of patients suffering cardiac arrest is still poor. Until today, no drug therapy has shown to improve longterm survival after cardiac arrest. Thrombolysis has been shown to be an effective therapy in patients with acute myocardial infarction (AMI) or massive pulmonary embolism (PE). ⋯ Although numerous small clinical studies have shown the efficacy of thrombolysis during CPR in selected patients, the generalized treatment of patients suffering cardiac arrest with thrombolytics can not be recommended based on current clinical evidence. According to the recent CPR guidelines, thrombolysis may be considered in cardiac arrest patients with suspected massive PE or as a so-called rescue therapy after unsuccessful conventional CPR in patients with a suspected thrombotic cause of cardiac arrest. The risk of severe bleeding complications following thrombolysis during CPR seems to be outweighed by the potential benefit of this therapy in selected patients.
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Rivaroxaban (Xarelto) is a novel, oral, direct Factor Xa (FXa) inhibitor in late-stage development for the prevention and treatment of thromboembolic disorders. Rivaroxaban inhibits clot-associated and free FXa activity, and prothrombinase activity, and reduces thrombin generation. In animal models, rivaroxaban prevented venous and arterial thrombosis, and was effective at treating venous thrombosis. ⋯ In a phase III study, rivaroxaban demonstrated significantly superior efficacy to enoxaparin for thromboprophylaxis after total knee arthroplasty, with similar low bleeding. Rivaroxaban is also being assessed for the treatment and secondary prevention of VTE, prevention of stroke in patients with atrial fibrillation and secondary prevention in patients with acute coronary syndrome. Rivaroxaban is a promising alternative to current pharmacological agents for thromboembolic disorders.
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Therapy with acetylsalicylic acid (ASA) and/or clopidogrel is used to achieve prophylactic inhibition of platelet aggregation in patients with arterial thrombosis. We examined if aggregometry can be used to see the effect of antiplatelet drugs (ASA 30, 50, 100, 300 mg/d, clopidogrel 75 mg/d or ASA 100 + clopidogrel 75 mg/d). A modified platelet aggregation test was used to investigate maximum aggregation in response to ADP, collagen, adrenalin and arachidonic acid. ⋯ Patients on clopidogrel alone were found to have prolonged aggregation when induced with ADP, collagen and arachidonic acid. The failure rate to achieve adequate platelet inhibition on 100 mg/d ASA, 75 mg/d clopidogrel or combination therapy was 27%, 26% and 7%, respectively. Our results demonstrate that platelet inhibition in aggregometry is inadequate in many patients with arterial thrombosis.
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The findings of a large prospective study designed to identify primary and/or secondary haemostatic disorders before surgical interventions are presented. A total of 5649 unselected adult patients were enrolled to identify impaired haemostasis before surgical interventions. Each patient was asked to answer a standardized questionnaire concerning bleeding history. ⋯ The positive predictive value (to detection of impaired haemostasis) of the PFA-100: collagen-epinephrine with the standardized questionnaire was high (82%), but the negative predictive value was higher (93%). The use of a standardized questionnaire and, if indicated, the PFA-100: C/E and/or other specific tests not only ensure the detection of impaired haemostasis in almost every case but also a significant reduction of the costs. Based on these data, national regards are formulated or under construction.