Randomized, Double-Blind, Placebo-Controlled Trial of Colchicine to Prevent Post-Operative Atrial Fibrillation After CABG With Strategy-Stratified Randomization

This single-center, prospective, randomized, double-blind, placebo-controlled clinical trial aims to evaluate the efficacy of colchicine in preventing post-operative atrial fibrillation (POAF) following coronary artery bypass grafting (CABG) and to compare its pharmacologic and clinical effects between different surgical strategies - off-pump CABG (OPCAB) and on-pump CABG (ONCAB).

Post-operative atrial fibrillation is one of the most common arrhythmias after CABG, with an incidence of approximately 50%, and is associated with prolonged ICU and hospital stay and increased healthcare utilization. Intravenous amiodarone is commonly used for POAF treatment but may increase the risk of catheter-related infection. Colchicine, an anti-inflammatory and immunomodulatory agent, has shown potential to reduce postpericardiotomy syndrome and POAF in small-scale studies, but existing evidence remains inconsistent, and most prior trials did not distinguish between surgical strategies.

In this trial, 400 adult patients undergoing elective CABG will be enrolled and randomized in a 1:1 ratio within each stratum (OPCAB and ONCAB) to receive either colchicine or placebo. The treatment group will receive colchicine 0.5 mg orally twice daily, starting on postoperative day -3 and continuing through postoperative day 7. The placebo group will receive identically appearing tablets on the same schedule.

The primary endpoint is the incidence of new-onset atrial fibrillation within 14 days after surgery, defined as any episode lasting ≥30 seconds documented by 12-lead ECG, continuous telemetry, or Holter monitoring.

Secondary outcomes include the incidence and management of other arrhythmias (atrial flutter, supraventricular tachycardia), total dose and duration of intravenous amiodarone, ICU and total hospital length of stay, ischemic stroke or TIA, infection events (including catheter-related infection), and 30-day readmission. Safety outcomes will include gastrointestinal intolerance, hepatic enzyme elevation, creatine kinase elevation with myalgia, hematologic abnormalities, and serious adverse events (SAE).