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Abstract Unstable angina is a clinical model of coronary ischemia that is complicated in 10-14% of patients by myocardial infarction,vascular death or both (Duncan et al., 1979). Evidence has been accumlating that platelets are involved in cardiovascular complications of arteriosclerotic origin, and several trials have been made, therefore, to assess whether antiplatelet therapy can improve the natural history of ischemic heart disease (Klint et al., 1986). There is compelling evidence from several large scale trials that aspirin is beneficial in treatment of unstable angina (The RISK group., 1990). ln contrast, placebo controlled trials ofheparin therapy have produced discordant results (Theroux et al., 1988). Nonetheless, patients frequently receive both aspirin and heparin during the acute phase of unstable angina despite the lack of evidence from clinical trials that combination therapy is supenor to treatment with aspirin alone (Holdright et al., 1994). The striking differences in aspmn efficacy in various forms of myocardial ischemia as well as marginal results in most other patients with the stable coronary artery disease, highlights the proplem facing investigators who design clinical trials as well as physicians who must recommend appropriate treatment for their patients (Theroux et al., 1994). Introduction and Aim of the work **2** Consequently several treatment strategies have evolved for management of patients with unstable angina, some ofthem showed that combination of aspirin and heparin confers no benefit to treatment with aspirin alone (Holdright et al., 1994), other showed that heparin is more effective in controlling myocardial ischemia in patients with unstable angina (NeriSerneri- GG et al, 1995) and that heparin prevents myocardial infarction better than aspirin during the acute phase of unstable angina (Theroux et al, 1993), other studies showed that combination of both heparin and aspirin gives the best results (Cohen et al., 1994). Ticlopidine is a potent inhibitor of platelet aggregation. It has been shown to significantly decrease the frequency of chest pain due to ischemia and the frequency of electrocardiographic signs of myocardial ischemia (Fox et al., 1982). It has been shown also to siginificantly decrease the incidence of ischemic complications during coronary angioplasty and to prevent reocclusion after thrombolysis and after PICA (Ketzume et al, 1993). Ticlopidine doesn’t cause GIT bleeding and unlike aspirin it may be used in patients having peptic ulceration (Gabriel Khan., 1992). |