This is another elegant investigation from the Cleveland Clinic cardiovascular surgical experience and the Atrial Fibrillation Innovation Center [1Koch C.G. Li L. Van Wagoner D.R. Duncan A.I. Gillinov A.M. Blackstone E.H. Red cell transfusion is associated with an increased risk for postoperative atrial fibrillation.Ann Thorac Surg. 2006; 82: 1747-1757Abstract Full Text Full Text PDF PubMed Scopus (128) Google Scholar]. It brings together two of the most vexing postoperative care issues in cardiac surgery, namely, the need for red blood cell (RBC) transfusion and the occurrence of postoperative atrial fibrillation. That they may be linked, as suggested by this investigation, has not been previously established. Table 1 illustrates that overall, the patients who have postoperative atrial fibrillation (AF) develop have received more in quantity and type of blood products, including RBCs, fresh frozen plasma, and platelets. These patients also manifest the usual preoperative risk factors for AF (age, prior AF, valve procedures, chronic obstructive pulmonary disease), and had higher inotropic requirements. Preoperative hematocrit was higher in the non-AF cohort. The multivariate regression analysis demonstrated that intraoperative RBC transfusion, female gender, and preoperative statin use were protective against the development of postoperative AF. The propensity analysis for on-pump cases demonstrated that postoperative RBC transfusion is an independent risk factor for AF. As the number of RBC units increased, so did the likelihood of AF. In the off-pump comparison, female gender, but not intraoperative RBC transfusion, ameliorated the postoperative transfusion impact on AF. Although the cohort number is small, this propensity analysis also demonstrated an effect from postoperative RBC transfusion. Time is the confounding variable here, because to fully understand this relationship requires the linking of events separated by as much as 72 to 96 hours. Data support the authors’ hypothesis that this link may be mediated by the inflammatory effect of RBC transfusion. Alternatively a major contributing factor here may be the need for intracardiac volume resuscitation in the patients who receive RBCs, and the effect of atrial volume changes on atrial stretch and nonuniform dispersion of refractoriness leading to postoperative AF. The findings in the off-pump coronary artery bypass cohort suggest that factors in addition to inflammation may be contributing to this link. Of course the indication for RBC transfusion (low oxygen carrying capacity vs bleeding vs volume requirement) is not available, so that at present the mechanism for this link remains unknown. Importantly the recommendation to carefully consider the indications and benefits and risks associated with transfusions in cardiac surgery patients is further strengthened by this investigation. Additional studies examining the link established in this analysis may ultimately provide new information to address each of these remaining thorny issues in adult cardiac surgery. Red Cell Transfusion is Associated With an Increased Risk for Postoperative Atrial FibrillationThe Annals of Thoracic SurgeryVol. 82Issue 5PreviewAtrial fibrillation (AF) is a common complication after cardiac surgery and is associated with increased resource utilization. Recent evidence supports a role of inflammation in the development of AF. It is also known that red blood cell transfusion modulates inflammation by increasing plasma levels of inflammatory markers. Therefore, we tested the hypothesis that red blood cell transfusion increases the risk of postoperative AF for patients undergoing cardiac surgery. Full-Text PDF