To compare the effect of alirocumab with placebo on the occurrence of cardiovascular (CV) events (composite endpoint of coronary heart disease (CHD) death, non-fatal myocardial infarction (MI), fatal and non-fatal ischemic stroke, unstable angina (UA) requiring hospitalization) in participants who experienced an acute coronary syndrome (ACS) event 4 to 52 weeks prior to randomization and were treated with evidence-based medical and dietary management of dyslipidemia.