Blood transfusion and the risk of atrial fibrillation after cardiac surgery

Red blood cell transfusion (Tx) induces a proinflammatory state. Inflammatory mediators are associated with an increased risk of postoperative atrial fibrillation (AF). Therefore, in this study we determined the association between AF and Tx after isolated coronary artery bypass graft surgery (CABG).

Between January 2008 and December 2010, a total of 879 patients underwent CABG. Of these, 815 (92.7%) had complete data extracted from our institution's Society of Thoracic Surgeons (STS) database. Predictors of AF development among four levels of Tx versus nontransfused patients were examined. Multivariable logistic regression and propensity score matching models were used.

The mean age was 65.8 years (±10.3), 77.4% were male, and 54.4% had an STS predicted risk score (mortality/morbidity) of ≥10%. A total of 564 (69.2%) had at least one unit of Tx. Adjusting for age, sex, time on pump, congestive heart failure, stroke, creatinine level (<1.5 mg per deciliter vs. ≥1.5), STS morbidity/mortality score, perioperative myocardial infarction (MI), cross-clamp time, medications, and hemoglobin level, the odds ratio (OR) of AF increased with increasing Tx (OR, 1.36; 95% confidence interval [CI], 1.11 to 1.68; p = 0.003). The odds of AF increased 61% with each increasing level of Tx (OR, 1.61; 95% CI, 1.15 to 2.26; p = 0.006, by propensity analysis).

Perioperative Tx may be associated with excess AF following CABG. This risk increases with increasing number of Tx.