Aims: Red blood cell transfusion is associated with increased mortality among patients with acute coronary syndromes, but little is known about the consequences of transfusion in a contemporary setting of ST-segment elevation myocardial infarction. We describe the association between transfusion and 90-day mortality among patients with acute myocardial infarction treated with primary percutaneous coronary intervention.
Methods and results: Analyses were performed on 5532 patients with ST-elevation myocardial infarction from the Assessment of Pexelizumab in Acute Myocardial Infarction trial. The primary objective of this analysis was to ascertain the relation between red blood cell transfusion and 90-day mortality in patients with recent myocardial infarction. We initially determined the baseline and in-hospital predictors of transfusion (multivariable logistic regressions) and subsequently assessed the association between transfusion and mortality using a series of Cox proportional hazards regression combined to a landmark analyses. A total of 213 patients (3.9%) received a transfusion. Transfusion remained significantly associated with mortality [hazards ratio = 2.16 (1.20-3.88)], despite adjustment for baseline characteristics, in-hospital co-interventions, and for propensity of receiving a transfusion. Among patients who survived to hospital discharge, however, the hazard of death was not different in patients treated with transfusion.
Conclusion: Transfusion is associated with 90-day mortality in acute myocardial infarction treated with primary percutaneous coronary intervention. Although transfusion may be causally related to mortality, it is likely that at least part of the association is due to confounding. This association illustrates the complex relationship between transfusion, bleeding, and mortality and underscores the need for further research to understand the relationship between transfusion and clinical outcomes.