RESUMO
On the assumption that antithrombotic drugs are able to reduce the incidence of any vascular event independently of where it first occurs, they are used for the secondary prevention of arterial vascular disease in different locations. The Antiplatelet Trialists' Collaboration meta-analysis has shown that the net benefit of antiplatelet drugs in the prevention of stroke, acute myocardial infarction and vascular death is about the same for patients with prior stroke or prior myocardial infarction. Most of the trials included in the Antiplatelet Trialists' Collaboration meta-analysis used aspirin, which was shown to lower the risk of stroke, myocardial infarction, and vascular death in patients with a history of transient ischemic attack or stroke. Aspirin should be given to patients operated on for symptomatic carotid stenosis and should be considered for asymptomatic patients. In a comparative study ticlopidine (500 mg) vs aspirin (650 mg), ticlopidine reduced the relative risk of vascular events by 9% and of recurrent stroke by 21%. When clopidogrel (75 mg) was compared with aspirin (325 mg), a 7.3% relative risk reduction was seen in the stroke group (6431 patients) of the CAPRIE study; a reduction in hemorrhagic events, especially in gastrointestinal bleeding, was also seen. At variance with previous studies, the ESPS-2 showed an advantage when dipyridamole (400 mg) was added to aspirin (50 mg). Oral anticoagulants are more effective than aspirin in the prevention of cardioembolic stroke in patients with atrial fibrillation. The higher efficacy of indobufen with respect to aspirin in this particular setting needs confirmation. Inhibition of thrombosis may be one of the mechanisms explaining the effect of statins in reducing both stroke and cardiac events in high-risk patients.