my personal edition > angina pectoris/mi > news


  E-Mail this DGReview to a colleague

DGReview

Low Molecular Weight Heparin as Effective as Unfractionated Heparin During Myocardial Infarction

Adjunctive low molecular weight heparin (LMWH) is at least as effective as unfractionated heparin (UFH) during the acute phase of myocardial infarction (MI), concludes the author of a new review article on the subject.

David Brieger, PhD, with the Department of Cardiology, at the University of Sydney, New South Wales, Australia, discussed the advantages and disadvantages of using UFH and LMWH during ST-Segment Elevation MI (STEMI). He also discussed the use of LMWH as an adjunct to streptokinase and fibrin-specific thrombolysis as well as the use of prehospital fibrinolysis with LMWH.

"Randomized clinical trials have shown that LMWH is at least as effective as UFH as an adjunct to both fibrin-specific and streptokinase-based thrombolytic regimens," Dr. Brieger states. He also points out that LMWH also has more favourable effects on secondary ischaemic events following STEMI, and the clinical benefits are achieved without an increase in major bleeding or thrombocytopenia.

According to Dr. Brieger, data have not confirmed the benefits of UFH over placebo as adjunctive therapy to thrombolysis agents. In addition, UFH has several disadvantages including the need for coagulation monitoring, difficulties attaining a stable and reliable anticoagulant effect, and the risk of hemorrhagic side effects.

By comparison, LMWH binds less strongly to circulating plasma proteins, resulting in a longer half-life and more stable levels of anticoagulation. Furthermore, LMWH results in greater inhibition of thrombin generation (higher anti-factor Xa:anti-factor IIa ratio) and prolonged anti-factor Xa activity.

Additional advantages of LMWH include greater inhibition of von Willebrand factor and less platelet activation, resulting in a greater net antiplatelet effect. In addition, patients receiving LMWH do not require coagulation monitoring, and it is conveniently administered subcutaneously, either once or twice daily.

Furthermore, LMWH has an acceptable safety profile and is associated with fewer in-hospital recurrent ischaemic events than UFH, Dr. Brieger notes.

"These clinical advantages, together with its convenience and modest cost, ensure that LMWH should evolve as the adjunctive antithrombotic agent of choice for patients with STEMI," he concludes.




Clin Cardiol 2004;27:3-8. "Optimizing adjunctive antithrombotic therapy in the treatment of acute myocardial infarction: a role for low-molecular-weight heparin"

E-Mail this DGReview to a colleague

To print, use this version