Background: Very little is known about the determinants of blood transfusions in patients undergoing coronary artery bypass graft surgery.
Study design and methods: To identify factors that influenced the transfusion of red cells, platelets, plasma, and cryoprecipitate, statistical methods were used to study 2476 consecutive diagnosis-related group 106 and 107 patients in five teaching hospitals who underwent coronary artery bypass surgery between January 1, 1992, and June 30, 1993.
Results: The likelihood of red cell transfusion was significantly associated with 10 preoperative factors: 1) admission hematocrit, 2) the patient's age, 3) the patient's gender, 4) previous coronary artery bypass surgery, 5) active tobacco use, 6) catheterization during the same admission, 7) coagulation defects, 8) insulin-dependent diabetes with renal or circulatory manifestations, 9) first treatment of new episode of transmural myocardial infarction, and 10) severe clinical complications. Platelet and/or plasma transfusions were strongly associated with the dose of red cells transfused. Transfusion requirements and other in-hospital outcomes were associated with patient characteristics, surgical procedure (reoperation vs. primary procedure), and the conduits used for revascularization (venous graft only, venous and internal mammary artery graft, or internal mammary artery graft only). Blood resource use and donor exposures were evaluated with respect to the risk to patients of contracting hepatitis C virus and human immunodeficiency virus infections.
Conclusion: The classification of coronary artery bypass graft patients on the basis of attributes known preoperatively and by conduits used yields subsets of patients with distinctly different transfusion requirements and in-hospital outcomes.