Association between anemia and blood transfusion with long-term mortality following cardiac surgery.
This study by Padmanabhan et al. is a well-conducted retrospective analysis that confirms that anaemia before cardiac surgery is strongly associated with long-term mortality.
The impact of preoperative anaemia seems to be stronger than and outweigh the risk of RBC transfusion, especially with low volumes (1-2 units) of RBCs that were not associated with a higher risk of mortality. The importance of preoperative anaemia is underscored by the interaction analysis of preoperative anaemia and transfusion, which showed no association.
However, these results need to be interpreted with great caution before it can be concluded that RBC transfusions are safe. There are too many data out showing different results (strong impact on adverse reactions) for RBC transfusions. While confirming preoperative anaemia as a risk factor in cardiac surgery, this study fuels the debate on the impact of RBC transfusions.
Finally, a large and well-designed prospective randomised study comparing causal anaemia treatment to RBC transfusions in anaemic cardiac surgery patients is needed to answer this question.
– Christian von Heymann