Preoperative white blood cells phenotype is associated with postoperative atrial fibrillation after cardiac surgery

Introduction Postoperative atrial fibrillation (POAF) contributes significantly to morbidity and mortality in patients after cardiac surgery that requires cardiopulmonary bypass. Inflammation, mediated by white blood cells, is involved in the pathogenesis of atrial fibrillation. Objective The aim of the study was to investigate whether a preoperative white blood cells phenotype before cardiac surgery could be associated with POAF. Method Flow cytometry was performed on fresh blood sample patients one day before they underwent aortic valve replacement and/or coronary artery bypass graft surgery at Lille University Hospital. Patients who already developed atrial fibrillation were excluded. Two panels were analyzed with sixteen clusters of differentiation (CD) on T-cells and eighteen CD on myeloid-cells. A Fortessa X20 and FlowJo software were used to analyze the samples. Results Forty-one patients were included and 8 (20%) of them developed POAF. Before cardiac surgery, patients who will develop POAF had already lower myeloid dendritic cells ( P  = 0.033), CD8+ naives T-cells ( P  = 0.016), effectors non-regulatory T cells ( P  = 0.024) and specially effectors Th17 non-regulatory T-cells ( P  = 0.0067) ( Fig. 1 ). Conclusion Patients who will develop POAF after a cardiac surgery displayed a preoperative white blood cells phenotype with T-cells and myeloid-cells modifications.