Cost-effectiveness of targeting patients undergoing cardiac surgery for therapy with intravenous amiodarone to prevent atrial fibrillation

OBJECTIVES: This study evaluated the cost-effectiveness of administering prophylactic intravenous (IV) amiodarone therapy to patients undergoing cardiac surgery according to their predicted risk of postoperative atrial fibrillation. BACKGROUND: Atrial fibrillation (AF) is a common complication of cardiovascular surgery that is associated with a significant increase in hospitalization costs. Intravenous amiodarone has been shown to decrease the incidence of postoperative AF. METHODS: All 8,709 patients who underwent coronary artery bypass grafting (CABG), 1,217 patients who underwent valve replacement and 624 patients who underwent CABG and valve replacement procedures (CABG + valve) from January 1, 1994, to June 30, 1999, at Emory University Hospitals were studied. Models predicting the risk of AF were developed using logistic regression; linear regression was used to estimate the influence of AF on hospitalization costs. Cost-effectiveness was evaluated for patient subsets identified according to their predicted risk of AF. RESULTS: Postoperative AF rates were 17.7% for CABG, 24.6% for valve and 33.8% for CABG + valve. Using 5,000 dollars as an acceptable cost per episode of atrial fibrillation averted, prophylactic IV amiodarone in CABG patients was not found to be cost-effective. Therapy would be recommended for roughly 5% of valve patients with a predicted risk of atrial fibrillation >45%, and roughly two thirds of CABG + valve patients who have a predicted risk of >30%. CONCLUSIONS: Cost-effectiveness of prophylactic IV amiodarone varies according to type of surgery and the predicted risk of atrial fibrillation. Older patients undergoing valve replacement, particularly those with a history of chronic obstructive pulmonary disease, and those undergoing concomitant CABG are likely to be the most appropriate candidates for IV amiodarone therapy in the perioperative period.