Impact of coronary collateral circulation and severity of coronary artery disease in the development of postoperative atrial fibrillation

OBJECTIVES: Atrial fibrillation (AF) after cardiac surgery has been reported to be approximately 30%, making it one of the most important causes of morbidity and mortality post surgery. Although various clinical and laboratory predictors and underlying mechanisms progressing to postoperative AF have been proposed, the role of ischaemia in pathogenesis is doubtful. In this study, the association of coronary collateral circulation (CCC) and severity of coronary artery disease (CAD) with the development of postoperative AF was investigated. METHODS: A total of 597 patients who underwent on-pump coronary artery bypass surgery were included in the study. Pre-, peri- and postoperative variables were recorded in a computerized database. CCC and severity of CAD were documented for each patient according to Rentrop classification and Gensini score. RESULTS: Postoperative AF was observed in 96 patients (16.1%). Advanced age, female gender, presence of hypertension and low haematocrit level were significantly associated with postoperative AF. By contrast, CCC and severity of CAD were not associated with postoperative AF (P = 0.22 and 0.5, respectively). Older age and lower preoperative haematocrit levels were the major predictors of postoperative AF development in the multivariate regression analysis. CONCLUSIONS: CCC and severity of CAD did not have a significant effect on the occurrence of postoperative AF, suggesting an ineffective role of myocardial ischaemia in the development of this condition.