Ticlopidine treatment for patients with unstable angina at rest. A further analysis of the study of ticlopidine in unstable angina. Studio della Ticlopidina nell'Angina Instabile Group.

Data collected to investigate the effects of ticlopidine in a subset of 489 patients with angina at rest accompanied by transient ischaemic electrocardiographic changes have been analysed. Of the 489 patients, 255 received conventional treatment including beta-blockers, nitrates, or calcium antagonists (control group); 234 received conventional treatment plus ticlopidine 250 mg b.i.d. (ticlopidine group). The predefined end-points were vascular death and acute myocardial infarction (AMI). The incidence of end-points was assessed according to the intention-to-treat principle. The post-hoc estimated statistical power was 80%. The rate of death or AMI in the 6-month follow-up period was reduced from 14.9 to 6.8% (-54.4%) (odds ratio: 0.42; confidence intervals: 0.22, 0.80). The incidence of fatal or nonfatal AMI was reduced from 12.2 to 4.3% (-65%) (odds ratio: 0.32; confidence intervals: 0.14, 0.70) and of nonfatal AMI from 10.2 to 3.8% (-63%) (odds ratio: 0.35; confidence intervals: 0.15, 0.80). Nineteen patients died; 12 in the control group (4.7%) and seven in the ticlopidine group (83%) (-36%) (odds ratio: 0.62; confidence intervals: 0.21, 1.74); five patients in the control group and only one in the ticlopidine group died of an AMI. The post-hoc estimated statistical power was 80%. However, we cannot draw definitive conclusions about the clinical effect of ticlopidine treatment in the patients with angina at rest accompanied by transient ischaemic electrocardiographic changes because the subgroup analysis was not planned a priori. Nevertheless, this report strongly suggests that such patients can benefit from antiplatelet treatment with ticlopidine; the benefit mainly depends on the protective effect against myocardial infarction.