Abstract 133: Outcomes Associated With Perioperative Amiodarone in Cardiac Surgery Patients Receiving Metoprolol

Abstract

Background: Post-operative atrial fibrillation (POAF) after cardiac surgery occurs frequently and the guidelines make a Class I recommendation for peri-operative betablocker use and a Class IIa recommendation for amiodarone use in high risk patients to reduce length of stay and mortality. Our aim was to study the association between perioperative amiodarone use and clinical outcomes in patients already receiving metoprolol, in a real-world cohort. Methods: Using the PREMIER, Inc. data warehouse, we identified patients ≥18 years without atrial fibrillation at baseline, who underwent elective cardiac surgery during years 2013-2014. We included patients with conditions replicating prior randomized controlled studies. We then excluded all patients not receiving metoprolol. Perioperative amiodarone use was defined as administered on the day of surgery or prior to surgery within the same hospitalization. After propensity matching, we compared outcomes for patients receiving perioperative amiodarone + metoprolol vs. those who received only metoprolol. The primary outcome was POAF and secondary outcomes were in-hospital mortality, length of stay and 1 month readmission among survivors. Results: Among 4351 patients who underwent cardiac surgery and received metoprolol at 212 hospitals, 997 (23%) were treated with perioperative amiodarone. We matched 928 (94%) of perioperative amiodarone treated group based on the propensity score. Table 1 shows baseline characteristics and outcomes of interest in the propensity matched cohort. Median age was 66 years and 74% were male. The propensity matched cohort was well balanced on type of surgery and comorbidities and some imbalances remained in demographic variables. After adjusting for unbalanced factors in the matched cohort, perioperative amiodarone+ metoprolol was associated with reduction in POAF (ARR 5.1%; RR 0.81, 95% CI 0.69-0.95). There were no differences in in-hospital mortality, length of stay, 1 month readmission or cost of hospitalization. Conclusions: In this large cohort of propensity matched patients undergoing elective cardiac surgery, perioperative amiodarone use was associated with a modestly significant reduction in POAF rates, but there were no significant relationships with mortality, length of stay, 1 month readmission or costs.