Perspective:

Prior retrospective studies have identified a relationship between bleeding after cardiac surgery and subsequent mortality, but it is not known whether this is attributable to bleeding itself, to anemia, or to transfusions. This study suggests that, in the specific population of patients who undergo CABG in the setting of an acute coronary syndrome, the culprit is transfusion of ≥4 units of RBCs––which was associated with both early (30-day) and late mortality, whereas mortality was not affected by bleeding without transfusion or with transfusion of platelets or fresh-frozen plasma. Transfusion thresholds were not prospectively specified in this multicenter study, and bleeding was more common among patients in whom CABG used fewer arterial grafts and in those who underwent more ancillary procedures; as such, bleeding severity at least in part reflected the patient population and surgical complexity. However, as the authors suggest, it appears prudent to concentrate efforts at minimizing bleeding associated with cardiac surgery in order to avoid the requirement for RBC transfusion.