الفهرس 
Platelet Function and ThrombosisOnly 14 pages are availabe for public view
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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).