The emerging role of low-molecular-weight heparin in cardiovascular medicine
Section snippets
Limitations of unfractionated heparin
UFH has a number of pharmacokinetic, biophysical, and biological limitations.10 Although LMWH overcomes the pharmacokinetic and some of the biological limitations of UFH (Table 1), both classes of heparin share the same biophysical limitations.
Low-molecular-weight heparins
LMWHs are fragments of UFH produced by chemical or enzymatic depolymerization processes that yield fragments approximately one-third the size of heparin.9 Like UFH, LMWHs are heterogeneous with respect to molecular size and anticoagulant activity. Because LMWHs are prepared by different methods of depolymerization and have different molecular weight profiles, they differ to some extent in their pharmacokinetic properties and anticoagulant profiles and, therefore, may not be clinically
Clinical experience with low-molecular-weight heparin preparations in cardiovascular disease
LMWHs have been evaluated in patients with unstable angina, acute myocardial infarction (MI), and after percutaneous coronary interventions.
Unresolved issues in low-molecular-weight heparin therapy
The unresolved issues related to the use of LMWH include (1) the need for laboratory monitoring in certain subgroups, (2) cost-benefit relative to UFH, (3) the interchangeability of the different LMWH preparations, and (4) reversal of anticoagulant effect with protamine sulfate.
One of the most appealing features of LMWHs is their more predictable dose response, which has been translated clinically into treatment with weight-adjusted dosing without laboratory monitoring. The only study that
Conclusion
Platelet deposition and thrombin generation at sites of plaque rupture lead to the formation of platelet-rich thrombi. Aspirin and UFH are limited in their ability to attenuate this process. LMWH has been evaluated in patients with acute coronary syndromes and in those undergoing percutaneous coronary interventions. This new class of anticoagulants has pharmacokinetic and biological advantages over UFH. These advantages have resulted in (1) greater convenience afforded by the ability to
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Microparticles as a strategy for low-molecular-weight heparin delivery
2011, Journal of Pharmaceutical SciencesCitation Excerpt :These are the major advantages that can potentially reduce the cost of health care.10,11 Because of the limitations of antithrombotic agents, new agents aimed at improving the safety of these medications have been developed over the last 10 years, but these did not seem to be more effective or safer than heparin.12−15 The strategies that have been used are based on the synthesis of new molecules, use of absorption promoters, intercellular junction modifications, and increases in the paracellular permeability, but these have not been successful due to the high doses needed to reach therapeutic blood concentration.
Models of blood coagulation
2006, Blood Cells, Molecules, and DiseasesMedical indications and considerations for future clinical decision making
2003, Thrombosis ResearchA novel approach to thrombin inhibition
2003, Thrombosis ResearchCurrent anticoagulant therapy - Unmet clinical needs
2003, Thrombosis ResearchThe use of low-molecular-weight heparins in outpatient oral surgery for patients receiving anticoagulation therapy
2002, Journal of the American Dental AssociationCitation Excerpt :The antidote is protamine sulfate. With unfractionated heparin there is a potential for drug-induced thrombocytopenia and thromboembolic disease.6–12 In cases in which patients receive unfractionated heparin, the patient usually is admitted to the hospital a few days before the surgical procedure, oral anticoagulation therapy is discontinued, and intravenous, or IV, heparin therapy is initiated.