Seminars in thrombosis and hemostasis
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Semin. Thromb. Hemost. · Jun 2004
Review Randomized Controlled Trial Clinical TrialRecombinant platelet factor 4 for heparin neutralization.
Protamine sulfate has been used for many years to reverse the effects of unfractionated heparin, but it can cause hemodynamic changes and other serious side effects. Platelet factor 4 (PF4) is a naturally occurring protein synthesized in megakaryocytes and eventually stored in the alpha granules of platelets for later release. Although the complete physiologic role of PF4 is unknown, it is highly effective for the neutralization of heparin anticoagulation. ⋯ Serial measurements of rPF4 levels showed a monophasic elimination pattern with a serum half-life of 25.5 +/- 13.5 minutes that was independent of dose administered. A randomized and blinded trial comparing rPF4 to protamine confirmed the safety and effectiveness of rPF4. Although rPF4 was initially being evaluated as a clinical alternative to protamine, it is not currently being developed for general clinical use.
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Semin. Thromb. Hemost. · Jun 2004
Randomized Controlled Trial Clinical TrialBivalirudin, blood loss, and graft patency in coronary artery bypass surgery.
A safe and effective alternative is needed for patients in whom unfractionated heparin (UFH) or protamine is contraindicated (e.g., those with heparin-induced thrombocytopenia or allergy to protamine). Furthermore, choice of anticoagulant may influence graft patency in coronary surgery and may therefore be important even when there is no contraindication to UFH. Direct thrombin inhibitors have several potential advantages over UFH, demonstrated in acute coronary syndromes. ⋯ Median graft flow was significantly higher in the bivalirudin group. We concluded that anticoagulation for OPCAB surgery with bivalirudin was feasible without a clinically important increase in perioperative blood loss. A larger study is needed to investigate the impact of improved graft patency on other clinical outcomes after cardiac surgery.
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Semin. Thromb. Hemost. · Feb 2004
ReviewHeparin and low-molecular-weight heparin therapy for venous thromboembolism: will unfractionated heparin survive?
Recent improvements in clinical trials methodology and the use of accurate objective tests to detect venous thromboembolism (VTE) have made it possible to carry out a series of randomized trials to evaluate various treatments for VTE. The results of these trials have resolved many of the uncertainties a clinician confronts in selecting the appropriate course of anticoagulant therapy. These trials have shown that the intensity of both initial heparin treatment and long-term anticoagulant therapy must be sufficient to prevent unacceptable rates of recurrence of VTE. ⋯ Treatment with low-molecular-weight heparin (LMWH), which does not require monitoring or dose finding, has largely replaced unfractionated heparin for the initial management of VTE. Efficacy in terms of recurrent VTE or extension of thrombus has been at least as good with LMWH as unfractionated heparin and there is evidence that the incidence of major bleeding, heparin-induced thrombocytopenia, and osteoporosis are less with LMWH as compared with unfractionated heparin. Although unfractionated heparin may survive as a treatment option for acute VTE, its use has been largely supplanted by LMWH.
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Semin. Thromb. Hemost. · Oct 2003
ReviewHyperviscosity in polycythemia vera and other red cell abnormalities.
Thrombosis is a major cause of mortality and morbidity in polycythemia vera (PV). The wide range of thrombotic events reflects the complex picture in PV. There are multiple factors involved in thrombogenesis in this disease, including increased hematocrit, thrombocytosis, impaired fibrinolytic activity, platelet activation, leukocyte activation, endothelial damage, interactions between platelets and endothelium, various modalities of therapy, and increased in whole-blood viscosity. ⋯ Thrombotic complications can also occur in both arteries and veins and manifest as stroke, myocardial infarction, deep vein thrombosis, or pulmonary embolism. The hemodynamic principle is aptly applied in the management of PV. The most important objective is the reduction of the patient's hematocrit.
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Semin. Thromb. Hemost. · Apr 2003
Meta AnalysisAcquired thrombophilia in pregnancy: essential thrombocythemia.
The management of pregnant patients with essential thrombocythemia (ET) is a difficult problem. The clinical course of ET is mainly determined by thromboembolic complications. Pregnancy itself is a physiological hypercoagulable state. ⋯ A meta-analysis revealed a significant benefit for aspirin in comparison to no treatment. If cytoreductive therapy becomes necessary, interferon alpha appears to be the drug of choice. The value of heparin prophylaxis has not been established but may have a role in selected cases.