RESTENOSIS AFTER CORONARY STENT PLACEMENT AND RANDOMIZATION TO A 4-WEEK COMBINED ANTIPLATELET OR ANTICOAGULANT-THERAPY - 6-MONTH ANGIOGRAPHIC FOLLOW-UP OF THE INTRACORONARY STENTING AND ANTITHROMBOTIC REGIMEN (ISAR) TRIAL

Background Platelets and mural thrombus at the lesion site may play a key role in initiating the restenosis process after coronary intervent ions. The ISAR Trial provides a comparison of the outcomes of patients randomized to two different antithrombotic regimens administered for 4 weeks after successful coronary stent placement: combined antiplatel et therapy (aspirin plus ticlopidine) or a conventional anticoagulant regimen (phenprocoumon with initial overlapping heparin plus aspirin). Within the first 4 weeks after stent placement, combined antiplatelet therapy has been associated with a significant reduction of ischemic complications. In the present study, we examined whether combined anti platelet therapy administered for 4 weeks after stent placement is abl e to reduce the process of restenosis at 6 months. Methods and Results Of 517 patients initially randomized, 496 were eligible for 6-month a ngiographic follow-up. Scheduled angiography was performed in 432 of t he eligible patients (87.1%), 216 in each group. In a comparison of th e two groups, there were no significant differences in clinical and pr ocedural variables or in qualitative and quantitative lesion character istics before and after stenting. At 6 months, minimal luminal diamete r was 1.95+/-0.86 mm in the group with initial combined antiplatelet t herapy and 1.90+/-0.87 mm in the group with initial anticoagulant ther apy (P=.55). Late lumen loss was 1.10+/-0.81 and 1.15+0.75 mm (P=.54), and the restenosis rate was 26.8% and 28.9%, respectively (P=.70). Ta rget lesion revascularization rate was 14.6% in the antiplatelet thera py group and 15.6% in the anticoagulant therapy group (P=.85). Conclus ions This study shows that combined antiplatelet therapy (aspirin plus ticlopidine) administered for 4 weeks after coronary Palmaz-Schatz st ent placement does not result in a detectable benefit for the preventi on of restenosis compared with conventional anticoagulant therapy (phe nprocoumon with initial overlapping heparin plus aspirin).