Background: Studies in patients undergoing coronary artery bypass grafting (CABG) have shown an increased long-term mortality rates associated with perioperative blood transfusions. However, some studies in other patient populations have shown no effect on death or even a lowered mortality rate in patients receiving blood transfusions, which suggests that the effects of blood transfusion may be disease-dependent.
Methods: Data of all patients who underwent valve operations with or without associated CABG between October 2, 1991, and November 14, 2007, were obtained from the department's database and analyzed using logistic regression for 30-day and Cox models for long-term mortality to determine the effects of transfusion on death. To control for the potential interaction between transfusion and complications and sicker patients being more likely to receive blood, we separately analyzed the data for the different valve populations and used propensity analysis to control for sicker patients being more likely to receive blood.
Results: Of 1823 patients who underwent valve operations, the operation was isolated in 993 and combined with CABG in 830. By 30 days, 125 patients (6.9%) had died, and 717 (39%) were dead at follow-up. After controlling for type of operation and factors that influenced the transfusion decision, transfusion was associated with increased death only in patients who had combined valve and CABG, and not in isolated valve operations.
Conclusions: Transfusion had no effect on the mortality rate after isolated valve operations but was associated with increased mortality when valve operations were combined with CABG.