Antiplatelet treatment with ticlopidine in unstable angina. A controlled multicenter clinical trial. The Studio della Ticlopidina nell'Angina Instabile Group.

We conducted a controlled multicenter trial with central randomization and evaluation of events under blind conditions involving 652 patients with unstable angina. Patients were treated either with conventional therapy alone (group C) (n = 338) or with conventional therapy combined with an inhibitor of platelet aggregation, ticlopidine 250 mg b.i.d. (group C + T) (n = 314). Patients were assigned randomly within 48 hours of admission and followed up for 6 months. With the "intention-to-treat" approach, the primary end points, vascular death and nonfatal myocardial infarction, were observed in 13.6% of the patients in group C and in 7.3% of the patients in group C + T, which is a reduction in risk of 46.3% (p = 0.009). Vascular mortality was 4.7% in patients in group C and 2.5% in patients in group C + T, which is a reduction in risk of 46.8% (p = 0.139). The risk of nonfatal myocardial infarction was reduced by 46.1% (p = 0.039), with a frequency of 8.9% in patients in group C and 4.8% in patients in group C + T. New Q wave myocardial infarction occurred with a frequency of 6.8% in patients in group C and 3.8% in patients in group C + T, which is a reduction in risk of 44.1% (p = 0.091). Fatal and nonfatal myocardial infarction was 10.9% in patients in group C and 5.1% in patients in group C + T, which is a reduction in risk of 53.2% (p = 0.006). These findings confirm the importance of platelets in the pathogenesis of unstable angina and the usefulness of antiplatelet treatment for the prevention of cardiovascular events.