[Low molecular weight heparins in acute coronary syndrome]

Low molecular weight heparins (LMWH) have gained an increased role in the treatment of acute coronary syndrome within the last years. Compared to unfractionated heparins LMWH are user-friendly (high bioavailability after subcutaneous application, no needed routine control of plasma efficacy).

International trials have demonstrated a comparable (dalteparin, nadroparin) or even higher (enoxaparin) efficacy of LMWH compared to unfractionated heparin in the treatment of patients with unstable angina or non-Q-wave infarction. The use of LMWH has thereby been accompanied by a low rate of side effects. Enoxaparin appears to have the highest efficacy compared with other LMWH in the acute phase of disease, but confirming "head-to head" studies with different LMWH are lacking. A significant higher efficacy of a prolonged treatment with LMWH compared to placebo has been shown in one study (FRISC-2) in unstable patients who were not treated by coronary intervention in the early phase of disease. This lasted for about 60 days but was associated with a higher risk of bleeding.

Currently, prospective clinical trials investigate the efficacy of combined use of LMWH with thrombolytics, GPIIb/IIIa blockers and the optimal dosage of LMWH during coronary interventions.