Role of Irbesartan in Prevention of Post-Coronary Artery Bypass Graft Atrial Fibrillation

Background and Objective: Atrial fibrillation (AF) is a common complication of cardiothoracic surgery (CTS). Existing evidence about the potential protective role of angiotensin II type 1 receptor antagonists (angiotensin receptor blockers [ARBs]) for post-CTS AF has been limited and conflicting. In this single-blind, open-label, randomized prospective pilot study, we evaluated the potential protective role of irbesartan (an ARB) in post-coronary artery bypass graft (CABG) AF. Methods: A total of 100 consecutive patients undergoing CABG were randomly assigned to irbesartan (n = 50) versus no irbesartan (n = 50) for 5 days prior to the scheduled surgery. Data were collected for imaging studies, laboratory values, and pen-operative details. Patients were monitored post-operatively for in-hospital AF episodes. Unadjusted and adjusted logistic regression analysis was performed to assess the effect of irbesartan on the incidence of post-CABG AF. Results: A total of 14 patients developed AF during their post-operative hospital stay. The incidence of AF in patients who received irbesartan was 6% (n = 3) compared with 22% (n = 11) in patients who did not receive irbesartan (p = 0.021). Univariate logistic regression analysis identified irbesartan and age as statistically significant variables. An adjusted multivariate logistic model identified irbesartan as an important protective factor against development of post-CABG AF (adjusted odds ratio [OR] 0.20; 95% confidence interval [CI] 0.04, 0.94; p = 0.04). Increasing age (adjusted OR 1.09, 95% CI 1.01, 1.17; p = 0.03) was also identified as an independent risk factor for development of post-CABG AF. Conclusion: Pretreatment with irbesartan tends to have a significant protective effect against the occurrence of AF during the post-operative period in patients undergoing CABG.