Tirofiban therapy for patients with acute coronary syndromes and prior coronary artery bypass grafting in the PRISM-PLUS trial

The role of glycoprotein IIb/IIIa platelet receptor antagonist therapy for patients with an acute coronary syndrome (ACS) and a history of coronary artery bypass grafting (CABG) remains incompletely defined. We examined the outcomes of patients with an ACS and prior CABG who were treated with tirofiban versus placebo among subjects with prior CABG in the Platelet Receptor Inhibition in Ischemic Syndrome Management in Patients Limited by Unstable Signs and Symptoms (PRISM-PLUS) trial. Of 1,570 patients treated with tirofiban plus heparin (n = 773) or heparin alone (n = 797), 231 had prior CABG. Compared with patients without prior CABG, those with prior CABG were more likely to have risk factors for a complicated ACS course, including severe coronary artery disease and heart failure (all p <0.0001), typically had clinical predictors of benefit from tirofiban, such as ST-segment depression (p = 0.01) or a TIMI risk score ≥4 (p <0.001), and were more likely to die or have a myocardial infarction or refractory ischemia at all time points examined (p <0.0001). Among patients with prior CABG, decreases in the incidence of death, myocardial infarction, or refractory ischemia with tirofiban and heparin versus heparin alone were noted at 7 and 30 days (7 days: 16.9% vs 29.0%, p = 0.035; 30 days: 25.0% vs 40.2%, p = 0.015). Trends toward a decrease in death, myocardial infarction, and refractory ischemia with tirofiban and heparin versus heparin alone in the prior CABG subgroup were noted at 48 hours and 180 days (48 hours: 6.5% vs 14.0%, p = 0.09; 180 days: 37.1% vs 48.6%, p = 0.057). Bleeding rates were similar in patients with and without prior CABG. Tirofiban was well tolerated and tended to decrease the considerable risk for ischemic ACS complications in patients with prior CABG.