The effect of oxidative stress related with ischemia-reperfusion damage on the pathogenesis of atrial fibrillation developing after coronary artery bypass graft surgery

OBJECTIVES
We aimed to investigate the role of oxidative stress related with ischemia- reperfusion damage on the pathogenesis of atrial fibrillation (AF) developing after coronary artery bypass graft (CABG) surgery.

STUDY DESIGN
In our prospective, single-center study, 118 patients who underwent elective isolated on-pump CABG surgery were included. Patients were divided into two groups according to the development of postoperative atrial fibrillation (POAF) as Group 1: Patients who developed POAF, and Group 2: Patients who remained in sinus rhythm. In addition to preoperative demographic, laboratory, echocardiographic, intraoperative, and postoperative clinical characteristics, levels of plasma total oxidative status (TOS) after placement and removal of aortic cross clamp (ACC) were compared between the two groups. Predictors of POAF were also investigated by multivariate logistic regression analysis.

RESULTS
A comparison of preoperative demographic, laboratory, echocardiographic, and postoperative clinical characteristics between the two groups showed that patients in Group 1 were significantly older (65.6±7.20 vs. 59.6±9.07, p<0.001), had a lower hematocrit level (37.5±5.16 vs. 39.7±5.28; p=0.034), and an enlarged left atrium diameter (39±0.45 vs. 3.6±0.48; p=0.006). Changes in plasma TOS levels after placement and removal of ACC were statistically significant in Group 1 [13 (8.6- 23), 30 (18.1-47.3); p=0.001 vs. 14 (8.8-22.2), 24 (21.4-42.7); p=0.060]. Length of stay in the intensive care unit [3 (2-14) vs. 2 (1-58); p=0.001] and length of stay in hospital [7 (6-85) vs. 7 (5-58); p=0.001] were prolonged in Group 1. In multivariate logistic regression analysis, aging (odds ratio (OR): 1.088, 95% confidence interval (CI): 1.005-1.177; p=0.036), hematocrit level (OR: 0.718, 95% CI: 0.538-0.958; p=0.025), pump temperature (OR: 1.445, 95% CI: 1.059-1.972; p=0.020), and plasma TOS level (OR: 1.040, 95% CI: 1.020-1.050; p=0.040) were found to be independent predictors of POAF.

CONCLUSION
Ischemia-reperfusion damage related with ACC placement may be an important factor on the pathogenesis of POAF. Minimizing the oxidative stress occurring intraoperatively should be targeted for preventing mortality and morbidity due to POAF