In patients with acute coronary syndrome, several studies have shown poorer outcomes, including increased mortality, in transfused groups compared with nontransfused patients after adjustment for potential confounders [21, [35] [36] [37] ; similar findings have been reported in patients who undergo percutaneous coronary interventions (PCI) [38] . However, although still controversial, RBC transfusions may be useful in subgroups of elderly patients with acute myocardial infarction [39] or patients with ST elevation myocardial infarction (STEMI) [21] .