Preoperative serum levels of interleukin-6 and interleukin-8 as predictors of the development of postoperative atrial fibrillation among patients undergoing coronary artery bypass grafting surgery

Objectives
The aim of the study was to evaluate the ability of preoperative estimation of serum interleukins (IL-6 and IL-8) for predicting the possibility of development of postoperative atrial fibrillation (POAF) among patients who have undergone coronary artery bypass grafting (CABG) surgery.
Patients and methods
The study included 90 patients who underwent CABG, with a mean age of 63.8 ± 4.7 years. All patients underwent on-pump surgery with a mean aortic cross-clamping time of 65.9 ± 14.6 min and a mean cardiopulmonary bypass (CPB) time of 99.1 ± 19.7 min. Preoperative blood samples were collected for enzyme-linked immunosorbent assay estimation of serum IL-6 and IL-8 levels.
Results
After CABG surgery, 24 patients developed POAF (26.7%); five were female and 19 were male with a mean age of 64.1 ± 5.2 years. Four patients had a history of previous atrial fibrillation (AF), whereas 20 patients had no history of preoperative AF. Mean aortic clamping and CPB times were significantly longer in POAF patients compared with AF-free patients. Mean preoperative serum IL-6 and IL-8 levels were significantly higher in patients compared with controls, with significantly higher levels in POAF patients compared with AF-free patients. There was a positive significant correlation between the occurrence of POAF and history of preoperative AF, preoperative serum levels of IL-6 and IL-8, and aortic clamping and CPB times. Regression analysis defined elevated serum levels of IL-6 and IL-8, prolonged aortic clamping and CPB times, and history of preoperative AF as predictors of the occurrence of POAF among patients undergoing CABG in decreasing order of significance.
Conclusion
Inflammatory factors play a prominent role in the pathogenesis of POAF; high preoperative serum levels of IL-6 and IL-8 could aid in identification of patients liable to develop POAF, especially when associated with prolonged clamping time or preoperative history of AF.