Dual Antiplatelet Compared to Triple Antithrombotic Therapy in Anterior Wall Acute Myocardial Infarction Complicated by Depressed Left Ventricular Ejection Fraction

Abstract

Current guidelines recommend triple antithrombotic therapy (TT) consist-ing of warfarin, aspirin, and a P2Y12 inhibitor following an anterior ST elevation myocardial infarction (STEMI) complicated by extensive wall motion abnormalities. This recommendation, however, is based on data collected before percutaneous coronary intervention (PCI) became the standard of care for the treatment of STEMI. We designed a retrospective study of patients who received PCI for anterior STEMI over an 8-year period to compare rates of thromboembolic and bleeding events between patients receiving dual antiplatelet therapy (DAPT) and those receiving TT, including warfarin. Patients were included if the predischarge echocardio-gram showed extensive wall motion abnormality and an ejection fraction ≤35%. Patients with known left ventricular thrombus were excluded. A total of 124 patients met the criteria, with 80 patients in the DAPT group and 44 in the TT group. The median age was 58 years in the TT group and 64 years in the DAPT group (P < 0.04), with an average ejection fraction of 31%. Thromboembolic events occurred in 4 patients (5%) in the DAPT group compared with 3 patients (6.8%) in the TT group (P = 0.70). Bleeding occurred in 2 patients in the DAPT group and 4 patients in the TT group (2.5% in DAPT vs. 9.1% in TT group, P = 0.18). No dif-ferences in rates of clinical embolism or left ventricular thrombus were found. Our data support recent findings that warfarin may not be indicated for patients following PCI for anterior STEMI, even when significant wall motion abnormalities and reduced ejection fraction ≤35% are present. A cute thromboembolic events due to left ventricular thrombus (LVT) formation, particularly in patients with reduced ejection fraction (EF), remain a risk for patients surviving an anterior ST elevation myocardial infarction (STEMI) (1). Th e reported incidence of LVT forma-tion and subsequent embolization varies based on the timing of the echocardiographic examination and the diagnostic, an-ticoagulation, and reperfusion strategies utilized in managing the initial presentation but is noted to range from 0 to as high as 86% (1–9). Warfarin as a prophylactic strategy is therefore utilized and suggested in guidelines based on data derived from pooled results of studies done before catheter-based treatment of STEMI was prominent (10, 11). A recent report by Le May et al has suggested that warfarin treatment might be unneces-sary in patients managed by primary PCI and dual antiplatelet therapy (DAPT) (12). Th e potential adequacy of DAPT alone