Background: Amiodarone effectively reduces the incidence of postoperative atrial fibrillation (POAF) in randomized trials and guidelines give a Class IIa recommendation for its use in high risk patients to improve outcomes; but little is known about its effectiveness to prevent POAF in routine clinical practice. Our aim was to determine the association between perioperative amiodarone use and clinical outcomes in a real-world cohort.
Methods: We identified patients aged ≥18 years without atrial fibrillation at baseline, who underwent elective coronary artery bypass surgery ± heart valve surgery in a hospital that contributed to PREMIER, Inc. data warehouse during 2013-2014. We excluded patients to replicate patients enrolled in prior randomized controlled studies. Perioperative amiodarone use was defined as receipt of amiodarone on the day of surgery or prior to surgery within the same hospitalization. We used propensity scores to match patients who received perioperative amiodarone to patients who did not, and compared outcomes. Our primary outcome was POAF (not present on admission). Secondary outcomes included in-hospital mortality, 1 month-readmission among survivors, length of stay and cost.
Results: We examined 12,758 patients free of AF admitted at 235 hospitals, of which 2191 (17%) were treated with perioperative amiodarone. Baseline characteristics were well matched after propensity scoring. (Table 1) After adjustment, receipt of amiodarone was associated with reduction in POAF in the matched cohort (ARR 5.6%; RR 0.83, 95% CI 0.75-0.92) but was associated with greater risk of ventricular arrhythmias (OR: 1.66, 95% CI: 1.20 - 2.29), cardiogenic shock (OR: 1.66, 95% CI: 1.13 - 2.42) and higher hospitalization costs ($1,159, 95% CI: $373 - $1,946). There were no differences in in-hospital mortality, length of stay, 1 month readmission.
Conclusions: In this large cohort of propensity matched patients undergoing elective cardiac surgery, perioperative amiodarone use was associated with a modest reduction in POAF, but there was no significant relationship with mortality, length of stay, or 1 month readmission. However, we found a small increase in risk of ventricular arrhythmias, cardiogenic shock and costs; findings that have not previously been described and require further evaluation.