Abstract 16670: Anterior Myocardial Infarction and Low Ejection Fraction: Should We Anticoagulate?

Abstract

Introduction: Left ventricular (LV) thrombus formation is a recognized complication in patients with anterior STEMI. Warfarin is often used in this setting to prevent thrombus formation despite limited data to support this practice. We sought to determine the incidence of LV thrombus formation and assess the clinical benefit of anticoagulation for prophylaxis against LV thrombus and ischemic stroke in patients presenting with anterior STEMI and reduced ejection fraction (EF) who were treated with early reperfusion therapies and dual antiplatelet agents. Methods: Consecutive patients (N=298) with anterior STEMI and low post-infarct EF (<40%) presenting to a single center between 2001 and 2010 were identified using an institutional registry. Patient demographics, presence of LV thrombus, anticoagulation strategy, and clinical outcomes at 6 months were determined using chart review. Patients with thrombus on the initial post-infarct echocardiogram were excluded (N=26). The primary outcomes were bleeding, stroke, and death within 6 months of the infarct. Results: LV thrombus occurred in 8.7% of patients with anterior STEMI and EF <40%. The incidence of clinically relevant bleeding was 13.2% and ischemic stroke was 2.2%.There was no significant difference in the rates of bleeding, stroke, or death based on treatment with warfarin (see table). There were four fatal bleeds, all occurring in patients on warfarin therapy. Conclusions: The incidence of LV thrombus in this high-risk group of patients with anterior STEMI and reduced EF is approximately 9%. The rate of ischemic stroke at 6 months was not affected by the addition of warfarin to dual antiplatelet therapy. In conclusion, the rate of thrombus formation and ischemic stroke were low, while the rate of clinically relevant bleeding was relatively high, suggesting that the routine use of warfarin for prophylaxis is not warranted.