RESUMO
Looking to their efficiency in the treatment of venous thrombosis and the problems caused by non fractioned heparins (NFH) in the treatment of acute coronary syndromes, several studies were realised to prove the interests of fractioned heparins (FH) as good alternative therapeutics in acute coronary syndromes. A fist attempt, FRISC study, showed that dalteparin was superior to the placebo given in patients receiving aspirin (75 mg daily). In the FRIC study the pursuit of dalteparin between the sixth and the fortieth day, at a low dose, don't give benefits compared to aspirin given simply. Enoxaparin seems to be superior to the NFH in ESSENCE and TIMI IIB studies:--In ESSENCE study witch was included 3171 patients with unstable angina or non Q wave myocardial infarction and all patients received aspirin, enoxaparin compared to NFH reduced significantly the combined risk of death, myocardial infarction, recurrent ischemia and the need of revascularisation. These benefits persisted after a year of the study:--TIMI IIB study realised in 3910 patients confirmed the results of ESSENCE study. Furthermore, their proved efficiency in unstable angina and the non Q wave myocardial infarction, a recent study published this year (2002) concluded that the use of FH, in patients with myocardial infarction and receiving fibrinolytic treatment (streptokinase), was associated of a less frequent major adverse cardiac evenment (MACE) than in patients receiving NFH.