Major benefit from antiplatelet therapy for patients at high risk for adverse cardiac events after coronary Palmaz-Schatz stent placement: Analysis of a prospective risk stratification protocol in the intracoronary stenting and antithrombotic regimen (ISAR) Trial

Background: The Intracoronary Stenting and Antithrombotic Regimen (ISAR) Trial is a randomized study in which antiplatelet therapy is compared with anticoagulant therapy after coronary stent placement, showing a significantly lower rate of noncardiac and cardiac events with antiplatelet therapy. The present study is a report of the analysis of a prospective risk stratification protocol in the ISAR Trial and the association with the incidence of adverse cardiac events and stent vessel occlusion. Methods and Results: In all 517 patients randomized in the ISAR Trial, risk stratification was done with a list of 18 clinical, procedural, and angiographic variables: 165 patients with two or fewer criteria were classified as low risk, 148 patients with three criteria were classified as intermediate risk, and 204 patients with four or more criteria were classified as high risk. Within a 30-day follow-up, cardiac event rate (death, myocardial infarction, repeat intervention) was 6.4% for high-risk, 3.4% for intermediate-risk, and 0% for low-risk patients (P<.01). Stent vessel occlusion occurred in 5.9%, 2.7%, and 0%, respectively (P<.01). There was no significant difference between anticoagulant and antiplatelet therapy in the low- and intermediate-risk groups. In high-risk patients, however, the cardiac event rate was 12.6% with anticoagulant therapy and 2.0% with antiplatelet therapy (P=.007), and the rate of stent vessel occlusion was 11.5% and 0%, respectively (P<.001). Conclusions: This risk stratification protocol can help to identify patients at risk for adverse cardiac events and stent vessel occlusion. Patients in the high-risk group had the most benefit from antiplatelet therapy. These data suggest that antiplatelet therapy is the therapy of choice after coronary stenting specifically for patients with acute ischemic syndromes, difficult procedures, or suboptimal final results.