Minocycline Plus Amiodarone Versus Amiodarone Alone for the Prevention of Atrial Fibrillation After Cardiac Surgery (MINA)

• Atrial fibrillation [ Time Frame: 2 years ] [ Designated as safety issue: Yes ]
  

Currently, the most effective therapy to prevent PAF after cardiac surgery remains undetermined. Amiodarone administration should be considered to decrease the incidence of new-onset postoperative atrial fibrillation (PAF) after cardiac operations. However, PAF requiring anticoagulation therapy occurs in 40-50% of cases early after cardiac surgery despite amiodarone prophylaxis. PAF is associated with increased morbidity and mortality including complications resulting from long-term anticoagulation. The findings that an exaggerated inflammatory response manifested by elevated acute oxidative stress proteins, and the induction of apoptotic mediators in right atrial myocytes may be responsible for PAF, and that steroidal or non-steroidal anti-inflammatory drug therapy can reduce PAF support this mechanism as a possible etiological factor. Minocycline, a tetracycline antibiotic, has specific atrial myocyte anti-apoptotic effect which decreases right atrial tissue inflammation, oxidative stress activity and molecular indices of apoptosis. Apoptosis of cardiac myocytes is thought to be one etiologic factor underlying postoperative atrial fibrillation. These observations lead to this trial hypothesis that the addition of minocycline to amiodarone may favorably affect suppression of PAF. This randomized controlled trial compares the efficacy and safety of treatment effects of intravenous minocycline 100 mg daily x 5 days starting intra-operatively combined with oral amiodarone (400 mg twice daily for 7 days, then 200 mg twice daily for the next 7 days), versus the same dose oral amiodarone alone, in the prevention of PAF among adult patients undergoing coronary artery bypass grafts, heart valve replacement/repair, or combined procedures. All patients receive 150 mg intravenous amiodarone intraoperatively and a 2nd similar dose of amiodarone bolus is permitted for tachyarrhythmia any time within 24 hours after surgery. PAF is detected by telemetry during hospitalization and 2 weeks following hospital discharge, by a 12-lead electrocardiogram. The primary outcome is PAF occurrence. Secondary outcomes include thromboembolic stroke, need for pharmacologic or electric cardioversion, mediastinal exploration for anticoagulation-related bleeding, serious drug side effects, Clostridium difficile superinfection, length of hospital stay and 30-day mortality from cardiovascular causes. Based on a projected PAF incidence of 26% and assuming 5% dropout rate and a two-sided alpha of 0.05, this design requires 400 subjects to detect a reduction of 50% in the primary outcome with 90% power. This is a valuable trial that would affect the method in which the investigators practice.