Abstract 13440: The Asp358 A/C Polymorphism in Interleukin-6 Receptor Gene as a Novel Predictor of Atrial Fibrillation Following Coronary Artery Bypass Graft Surgery in Chinese Han Population

Objective: Growing evidences suggest that genetic variation in inflammatory cytokines may play a key role in the development of postoperative atrial fibrillation (POAF). This study aimed to examine the association between three single-nucleotide polymorphisms in interleukin-6 receptor (IL-6R) gene Asp 358 A/C, IL-6 gene -174 G/C and -597 G/A and POAF following coronary artery bypass grafting (CABG). Methods: This prospective study enrolled 371 Chinese Han patients undergoing first time isolated CABG. The primary endpoint was the occurrence of POAF lasting ≥ 5mins. The patients were grouped as either POAF or non-POAF according to their ECGs, which were continuously monitored for the first 7 postoperative days. Genotypes for IL-6R gene Asp358 A/C, IL-6 gene -174 G/C and -597 G/A were determined. Multivariate logistic regression analysis was performed to identify independent risk factors for POAF. Results: Overall, 112 (30.2%) patients developed POAF. There was no significant difference in demographic and clinic data between the two groups, except that patients in the POAF group were significantly older than those in the non-POAF group (p < 0.001), patients who had POAF appeared to have cerebrovascular disease more frequently than those who did not have POAF(p < 0.05). Although frequencies of alleles and genotypes of IL-6 gene -174 G/C and -597 G/A polymorphism were similar in both groups, the CC genotype distribution and C allele frequencies of IL-6R gene Asp358 A/C were significantly higher in patients with POAF than those without POAF (p = 0.003). Univariate logistic analysis showed that the CC genotype for IL-6R gene Asp358 A/C, age, and history of cerebrovascular disease emerged as predictors of POAF. Multivariate analysis shows that the CC genotype for IL-6R gene Asp358 A/C and age were independent predictors of POAF. The adjusted (OR 2.06; 95% CI, 1.16 - 3.63; p = 0.01) of the CC genotype for IL-6R gene Asp358 A/C for predicting POAF was even greater than the unadjusted (OR 1.22; 95% CI, 1.01- 1.64; p = 0.04). Conclusions: This study suggests IL-6R gene Asp358 A/C polymorphism may contribute to the genetic susceptibility of POAF after CABG in Chinese Han population.