Impact of Preoperative Atrial Fibrillation on In-Hospital Outcomes of Coronary Artery Bypass Grafting

Perioperative atrial fibrillation (AF) is associated with increased mortality, morbidity, and excess healthcare costs. The objective of our study was to assess if preoperative AF in patients undergoing coronary artery bypass grafting is a predictor of operative mortality, postoperative stroke, and need for postoperative dialysis by interrogating a large registry database. We included all isolated procedures performed between February 1996 and March 2019. We used a generalized linear mixed model to assess the effect of preoperative AF on mortality stroke and the need for postoperative dialysis after adjusting for the relevant confounders derived from EuroSCORE 2. Confounders considered included age, gender, neurological dysfunction, renal dysfunction, recent myocardial infarction, pulmonary disease, unstable angina, NYHA class, pulmonary hypertension, diabetes on insulin and peripheral vascular disease, and urgency of the operation. We treated the hospital and operating consultant as random effect variables. We also performed LV function subgroup analyses to assess the effect of preoperative AF on the outcomes of interest. The incidence of pre-existent AF in the cohort of patients we analyzed (N = 356,040 patients) was 3.5% (N = 12,664). In the unadjusted baseline characteristics, preoperative AF patients had more associated comorbidities. After adjustment, preoperative AF remained a significant predictor of increased mortality (odds ratio [OR]: 1.63, confidence interval [CI] 1.48-1.79, p0.001), stroke (OR: 1.33, CI 1.16-1.54, p = 0.001), and need for renal dialysis (OR:1.61, CI 1.46-1.78, p0.001). Preoperative AF was a significant predictor of adverse outcomes in patients with moderate and good LV function but not in patients with poor LV function (EF30%). Our study suggests that preoperative AF is associated with an increased risk for perioperative mortality and stroke in patients undergoing coronary artery bypass grafting.