Carvedilol Versus Metoprolol for the Prevention of Atrial Fibrillation After Off-Pump Coronary Bypass Surgery
Condition: Coronary Disease; Atrial Fibrillation
MeSH terms: Atrial Fibrillation; Coronary Disease
Study type: Interventional

Summary: 
      Postoperative new-onset atrial fibrillation (AF) is the most common complication stemming
      from coronary artery bypass graft surgery, and is associated with increased early and late
      mortality risk. Standard guidelines recommend β blockers for the prevention of AF; however,
      no prospective study has compared the relative efficacy of β-blocking agents. We hypothesize
      that carvedilol, a non-selective adrenergic blocker with both anti-inflammatory and
      antioxidant properties, is more effective than metoprolol, a conventional β1-selective
      antagonist, in suppressing new-onset AF following off-pump coronary bypass surgery. We have
      designed the Carvedilol or Metoprolol Post-Revascularization Atrial Fibrillation Controlled
      Trial (COMPACT) to test our hypothesis in a multi-center, open-label, and randomized
      controlled trial.
    

Detailed description: 
      Occurring in 20% to 50% of patients, postoperative new-onset atrial fibrillation (AF) is the
      most common complication of coronary artery bypass graft (CABG) surgery. Reports have
      indicated that the occurrence of postoperative AF is associated with a prolonged stay in the
      hospital, readmission to the intensive care unit, stroke, and, consequently, increased
      overall costs. Moreover, recent results from both retrospective and prospective observational
      studies suggest that its associated early and late mortality risk is high. During the past
      decade, off-pump coronary bypass (OPCAB) surgery has gained widespread acceptance as an
      alternative to conventional on-pump CABG surgery, as avoiding cardiopulmonary bypass and
      myocardial ischemia-reperfusion is thought to significantly reduce postoperative systemic
      complications. Nevertheless, recent studies have revealed that OPCAB surgery does not reduce
      the incidence of postoperative AF, possibly because the consistent inflammatory differences
      between on-pump CABG and OPCAB surgery are present only at the beginning of the postoperative
      course, or partially because general surgical trauma may play a greater role. It has thus
      been anticipated that, as with on-pump CABG surgery, OPCAB surgery has high AF-related
      mortality and morbidity risks, and the prevention of new-onset AF following OPCAB surgery
      should significantly reduce the risk of these outcomes. To date, most reviews reflect a
      growing consensus in favor of the prophylactic administration of β blockers. In addition, the
      American College of Cardiology/American Heart Association guidelines for CABG surgery
      recommend β blockers for the prevention of AF. To the best of our knowledge, however, no
      prospective study has evaluated the merits of a specific β-blocking agent or concluded that
      each of these agents is equally efficacious.

      Carvedilol, a non-selective beta adrenergic blocking agent approved for use in heart failure
      cases, has a number of ancillary activities including anti-inflammatory and antioxidant
      properties. Although the exact pathophysiology of new-onset AF following OPCAB surgery has
      not yet been elucidated, recent reports suggest that markers of inflammation and oxidative
      injury are elevated in patients with non-surgical AF. In addition, clinical studies indicate
      that, unlike the β1-selective agent metoprolol, carvedilol has incremental benefits for AF
      management in heart failure patients. The anti-inflammatory and antioxidant properties of
      carvedilol have generated interest in its use as a prophylaxis for postoperative AF.

      These considerations led to the organization of COMPACT, a multi-center, randomized
      controlled trial of 650 patients designed to test the hypothesis that carvedilol is more
      effective than metoprolol, a conventional β1-selective antagonist, in suppressing new-onset
      AF following OPCAB surgery.
    

Intervention name(s): Carvedilol versus Metoprolol
Intervention type(s): Drug
Intervention MeSH terms: Metoprolol; Carvedilol
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Prevention
Keywords: Adrenergic beta-Antagonists; Carvedilol; Metoprolol; Coronary Artery Bypass; Atrial Fibrillation