Abstract 18260: Local Interleukin-6 and Pericardial Drainage Volume are Associated with Atrial Fibrillation After Coronary Artery Bypass Grafting

Objective. To examine the relationship between IL-6, WBC, CRP levels and volume of pericardial drainage in patients with AF following CABG. Method. In 124 patients with sinus rhythm (SR) undergoing elective isolated CABG, IL-6, WBC count and CRP levels were measured in pericardial drainage and peripheral blood at six, 12, and 18 hours (hrs) postoperatively. The volume of pericardial drainage was also recorded at the same time interval. Two-factor ANOVA for repeated measures was used to test the trends of the above parameters and their relationship with postoperative AF (POAF). Results. AF occurred in 44 (35.5%) patients and IL-6 levels in pericardial drainage increased over time in this group (from 1353.9 pg/ml at six hours to 2189.2 pg/ml at 18 hrs), while it was peaked at 12 hrs and declined thereafter in the SR group (1541.5 pg/ml at six hours, 1906.3pg/ml at 12 hrs, and 1876.2 pg/ml at 18 hrs). Two-factor ANOVA for repeated measures showed that the change of mean IL-6 levels in drainage over time between the two groups was significantly different ( P = 0.016). The postoperative levels of IL-6 in peripheral blood declined slowly over 18 hours in both groups (from 71.61 pg/ml to 62.90 pg/ml and 85.56 pg/ml to 75.92 pg/ml, respectively). Interestingly, IL-6 levels in drainage were 28 and 22 times higher in drainage than those in blood in the AF and SR groups, while the difference of IL-6 levels in drainage and blood in the AF group was six times higher than in the SR group ( P = 0.014). Although the volume of drainage decreased over time in both groups, logistic regression showed that age adjusted total drainage of ≥ 430 ml during the first 18 hours post-op was an independent predictor of POAF (OR 3.91, 95%CI 1.55-10.27). CRP levels in the drainage of the AF and SR groups increased noticeably from 3.74 and 3.08 mg/L at six hours, to 16.76 and 15.45 mg/L at 18 hrs after surgery, and in blood from 9.95 and 9.82 mg/L to 41.70 and 41.36 mg/L, respectively. CRP levels in blood were higher than in drainage for both groups ( P < 0.001). There was no association between the occurrence of POAF and CRP levels or WBC in either drainage, or blood. Conclusion. IL-6 may be produced locally after CABG, and the levels of IL-6 in, as well as the volumes of pericardial drainage were associated with POAF.