Background

Coronary artery bypass grafting (CABG) carries a high risk of bleeding and allogeneic blood transfusions, both associated with poor outcomes. We assessed perioperative transfusions and factors associated with transfusion over an 18-year period in a detailed and validated nationwide patient cohort.

Materials and methods

This retrospective cohort study included 1,850 consecutive CABG patients operated on at Landspitali University Hospital in Iceland 2005–2022. Clinical data and transfusions of red blood cells (RBCs), fresh-frozen plasma (FFP) and platelets (PLTs) were obtained from medical records and the Icelandic Blood Bank and analysed across three 6-year intervals. A multivariable logistic regression model was used to identify factors associated with perioperative transfusion.

Results

A total of 1,181 (63.8%) patients were transfused with at least one blood product. RBCs, FFP and PLTs were transfused to 59.2%, 29.6% and 21.4%, respectively. The proportion of patients receiving any transfusion was significantly lower during the last compared to the first 6-year interval (48.0% vs. 74.9%, p < 0.001), primarily due to reduced number of RBC transfusions. The risk of transfusion decreased by 34% from the first interval to the last (RR = 0.66, 95% CI 0.59–0.73). Simultaneously, chest drain output decreased (470 mL within 24 h vs. 790 mL within 24 h, p < 0.001) and the proportion of patients undergoing re-exploration for bleeding tended to decrease (3.3% vs. 6.0%, p = 0.13), while preoperative use of aspirin (81.1% vs. 38.4%, p < 0.001) and clopidogrel (11.4% vs. 2.8%, p < 0.001), and perioperative administration of fibrinogen (28.5% vs. 2.8%, p < 0.001) increased significantly. Factors associated with transfusion included advanced age, female sex, chronic kidney disease and use of clopidogrel < 5 days before surgery, whereas aspirin use until surgery was not associated with transfusion. After adjustment, the odds of transfusion decreased by 84% from the first to the last interval (aOR = 0.16, 95% CI 0.11–0.22).

Conclusions

The proportion of CABG patients receiving perioperative transfusions in Iceland is relatively high, but the risk of transfusion has decreased markedly during the past two decades. This is most likely attributed to increased focus on patient blood management, including the implementation of transfusion guidelines and perioperative use of heparin titration, viscoelastic testing and cell salvage.