Myocardial salvage after ST-segment-elevation myocardial infarction: comparison between prasugrel and clopidogrel in the presence or absence of high-residual platelet reactivity

Background: The effect of prasugrel over clopidogrel on myocardial salvage in ST-segment-elevation myocardial infarction (STEMI) patients undergoing primary percutaneous coronary intervention (p-PCI) is not fully elucidated. Methods: Among 854 consecutive STEMI patients who underwent p-PCI, 446 patients were evaluated by two-phase (7 days and 3 months) single-photo emission computed tomography (SPECT). Patients were divided into two groups based on the loading P2Y12 inhibitor. The clopidogrel group was further divided based on the result of platelet function testing. Thus, the prasugrel group included 227 patients; the clopidogrel without high-residual platelet reactivity (HRPR) group, 109 patients; and the clopidogrel with HRPR group, 107 patients. The primary endpoint was the Myocardial Salvage Index (MSI), determined by SPECT. Results: The incidence of final TIMI 0/1 and TIMI myocardial perfusion grade 0/1 was higher in the clopidogrel with HRPR group (0.9%, 1.8%, and 7.5%, P = .002; 19.8%, 29.4%, and 41.1%, P = .0002, in the prasugrel, clopidogrel without HRPR, and clopidogrel with HRPR groups, respectively). The MSI was significantly lower in the clopidogrel with HRPR group (48% [27-66], 44% [30-72], and 36% [15-55], P = .006, respectively). Conclusions: Prasugrel in STEMI patients was associated with an increased MSI compared with clopidogrel in the presence of HRPR.