The impact of minor blood transfusion on the outcome after coronary artery bypass grafting

Purpose: To investigate the impact of minor perioperative bleeding requiring transfusion of 1-2 red blood cell (RBC) units on the outcome after coronary artery bypass grafting (CABG). Methods: Sixteen cardiac surgical centers contributed to the prospective European CABG registry (E-CABG). 1014 patients receiving 1-2 RBC units during or after isolated CABG were compared to 2264 patients not receiving RBCs. Results: In 827 propensity score matched pairs, transfusion of 1-2 RBC units did not affect the risk of in-hospital/30-day death (p = 0.523) or stroke (p = 0.804). However, RBC transfusion was associated with an increased risk of acute kidney injury (p = 0.008), sternal wound infection (p = 0.001), postoperative use of antibiotics (p = 0.001), prolonged use of inotropes (p < 0.0001), use of intra-aortic balloon pump (p = 0.012), length of intensive care unit stay (p < 0.0001) and length of in-hospital stay (p < 0.0001). Matched paired analysis excluding pre- and postoperative critical hemodynamic conditions showed that RBC transfusion was associated with an increased risk of major complications except in-hospital/30-day death. Conclusion: Minor perioperative bleeding and subsequent transfusion of 1-2 RBC units did not affect the risk of early death, but increased the risk of other major adverse events. Minimizing perioperative bleeding and prevention of even low-volume RBC transfusion may improve the outcome after CABG.