Abstract 14523: N-acetylcysteine for the Prevention of Atrial Fibrillation After Noncardiac Thoracic Surgery: A Double-blind, Randomized, Placebo-controlled Trial

Abstract

Introduction: Adding N-acetylcysteine (NAC) to amiodarone may mitigate inflammation and oxidative stress, preventing postoperative atrial fibrillation (POAF). NAC, reported to reduce cardiac surgery POAF, has not been tested in major thoracic surgery. Methods: Patients at high risk for POAF (BNP≥25pg/ml, male, age≥75, or history of AF) who underwent major thoracic surgery (n=154) were randomized to amiodarone + NAC (n=78) or amiodarone + placebo (n=76). Begun on arrival to the PACU were amiodarone 150 mg iv then 1 g/24 h iv x 48 h, and NAC or placebo bolus 50 mg/kg iv then 50 mg/kg/24 h iv x 48 h. The primary endpoint was sustained AF >30 s by telemetry (first 72 h) or symptoms within 7 days of surgery; patients with the primary endpoint underwent home ECG monitoring. Secondary endpoints were AF up to 1-year post discharge and systemic markers of inflammation. Results: Baseline characteristics were similar between arms (Table). POAF occurred in 15/78 NAC patients (19%) and 13/76 placebo patients (17%) (p=0.8). The trial was stopped at the interim analysis for futility. Regardless of treatment, of 28 patients with POAF, 3/28 (11%) were discharged in AF, and 1/28 (4%) met the primary endpoint after discharge. At 1-year, 7/28 patients with POAF (25%) had recurrent episodes of AF, and 1 developed persistent AF—none developed stroke. Inflammatory markers were similar between treatment arms; however, regardless of NAC, on postoperative day 2, patients with POAF (n=28) had higher CRP (p=0.008) and IL-6 (p=0.001) than patients without POAF (n=126). Conclusions: Compared to amiodarone alone, NAC + amiodarone did not reduce the incidence of POAF nor markers of inflammation early after major thoracic surgery. Recurrent AF episodes are common among patients with POAF within 1-year of surgery.