Incremental value of left ventricular systolic and diastolic function to determine outcome in patients with acute ST-segment elevation myocardial infarction: The echocardiographic substudy of the OASIS-6 trial

Background The echocardiographic substudy of the OASIS-6 trial evaluated the prognostic implications of left ventricle (LV) systolic and diastolic dysfunction early postacute ST-segment elevation myocardial infarction (STEMI) in patients treated with fondaparinux versus usual care. Methods Comprehensive echocardiograms were performed a median of 6 days after the index STEMI in 528 patients, 258 randomized to fondaparinux and 270 to usual care (unfractionated heparin or placebo), to assess LV systolic and diastolic function, LV mass, and LV end-systolic and end-diastolic volumes. A total of 245 (46.4%) patients were followed up for 3 months and 283 (53.6%) for 6 months. Major cardiac events (MACE) were defined as the composite of death, reinfarction, heart failure, or cardiogenic shock and resuscitated cardiac arrest. Results Patients with LV ejection fraction (LVEF) ≤ 45% and restrictive diastolic function (RDF) were at greatly increased risk of MACE (hazard ratio [HR] = 8.85, 95% CI, 4.21-18.60) compared to patients with LVEF ≥ 45% and without RDF. RDF remained a strong predictor for MACE in patients with LVEF ≥ 45% (HR = 4.38, 95% CI, 1.52-12.60) and in multivariate models adjusted for LVEF, LV end-systolic volume, and clinical variables. Conclusion In this large international trial, LV systolic and diastolic function, as determined by echocardiography early following STEMI, are incremental predictors of MACE. In addition, RDF is a strong independent predictor of MACE after STEMI across a broad range of LVEF.