Prasugrel versus clopidogrel in patients with ST-segment elevation myocardial infarction according to timing of percutaneous coronary intervention: a TRITON-TIMI 38 subgroup analysis (Trial to Assess Improvement in Therapeutic Outcomes by Optimizing Platelet Inhibition with Prasugrel-Thrombolysis In Myocardial Infarction 38).

OBJECTIVES: This study sought to evaluate the efficacy of prasugrel versus clopidogrel in ST-segment elevation myocardial infarction (STEMI) by the timing of percutaneous coronary intervention (PCI).

BACKGROUND: Treatment strategies and outcomes for patients with STEMI may differ when treated with primary compared with secondary PCI.

METHODS: STEMI patients in the TRITON-TIMI 38 (Trial to Assess Improvement in Therapeutic Outcomes by Optimizing Platelet Inhibition with Prasugrel-Thrombolysis In Myocardial Infarction 38) were randomized to prasugrel or clopidogrel on presentation if primary PCI was intended or later during secondary PCI. Primary PCI was defined as within 12 h of symptom onset. The primary endpoint was cardiovascular death, myocardial infarction (MI), or stroke. Because periprocedural MI is difficult to assess in the setting of STEMI, we performed analyses excluding these events.

RESULTS: Reductions in the primary endpoint with prasugrel versus clopidogrel (hazard ratio [HR]: 0.79; 95% confidence interval [CI]: 0.65 to 0.97; p = 0.022) were consistent between primary and secondary PCI patients at 15 months (HR: 0.89; 95% CI: 0.69 to 1.13 vs. HR: 0.65; 95% CI: 0.46 to 0.93; p interaction = 0.15). However, a tendency toward a difference in treatment effect at 30 days (HR: 0.68; 95% CI: 0.54 to 0.87; p = 0.002) was observed between primary and secondary PCI patients (HR: 0.81; 95% CI: 0.60 to 1.09 vs. HR: 0.51; 95% CI: 0.34 to 0.76; p interaction = 0.06). When periprocedural MI was excluded, the efficacy of prasugrel remained consistent among primary and secondary PCI patients at 30 days (HR: 0.53; 95% CI: 0.34 to 0.81 vs. HR: 0.44; 95% CI: 0.22 to 0.88; p interaction = 0.68) and 15 months (HR: 0.76; 95% CI: 0.56 to 1.03 vs. HR: 0.75; 95% CI: 0.46 to 1.21; p interaction = 0.96).

CONCLUSIONS: The efficacy of prasugrel versus clopidogrel was consistent irrespective of the timing of PCI, particularly in preventing nonprocedural events. (Trial to Assess Improvement in Therapeutic Outcomes by Optimizing Platelet Inhibition with Prasugrel-Thrombolysis in Myocardial Infarction 38; NCT00097591).