Coronary artery bypass surgery for acute coronary syndrome: A network meta-analysis of on-pump cardioplegic arrest, off-pump, and on-pump beating heart strategies

Abstract

Background: Coronary artery bypass grafting (CABG) in the setting of an acute coronary syndrome is a high-risk procedure, and the best strategy for myocardial revascularisation remains debated. This study compares the 30-day mortality benefit of on-pump CABG (ONCAB), off-pump CABG (OPCAB), and on-pump beating heart CABG (OnBHCAB) strategies.

Methods: A systematic search of three electronic databases was conducted for studies comparing ONCAB with OPCAB or OnBHCAB in patients with acute coronary syndrome (ACS). The primary outcome, 30-day mortality, was compared using a Bayesian hierarchical network meta-analysis (NMA). A random effects consistency model was applied, and direct and indirect comparisons were made to determine the relative effectiveness of each strategy on postoperative outcomes.

Results: One randomised controlled trial and eighteen observational studies fulfilling the inclusion criteria were identified. A total of 4320, 5559, and 1962 patients underwent ONCAB, OPCAB, and OnBHCAB respectively. NMA showed that OPCAB had the highest probability of ranking as the most effective treatment in terms of 30-day mortality (odds ratio [OR], 0.50; 95% credible interval [CrI], 0.23-1.00), followed by OnBHCAB (OR, 0.62; 95% CrI, 0.20-1.57), however the 95% CrI crossed or included unity. A subgroup NMA of nine studies assessing only acute myocardial infarction (AMI) patients demonstrated a 72% reduction in likelihood of 30-day mortality after OPCAB (CrI, 0.07-0.83). No significant increase in rate of stroke, renal dysfunction or length of intensive care unit stay was found for either strategy.

Conclusions: Although no single best surgical revascularisation approach in ACS patients was identified, the significant mortality benefit with OPCAB seen with AMI suggests high acuity patients may benefit most from avoiding further myocardial injury associated with cardiopulmonary bypass and cardioplegic arrest.

Keywords: ONCAB; OPCAB; OnBHCAB; acute coronary syndrome; coronary artery bypass grafting.

Figure 1

Network diagram of direct comparisons. The thickness of each arm and size of each node represents the number of data points in that comparison and number of included studies, respectively. OnBHCAB, On‐pump beating heart CABG; ONCAB, on‐pump CABG; OPCAB, Off‐pump CABG.

Figure 2

ONCAB versus OPCAB pairwise meta‐analysis forest plot. ONCAB, on‐pump CABG; OPCAB, Off‐pump CABG.

Figure 3

ONCAB versus OnBHCAB pairwise meta‐analysis forest plot. OnBHCAB, On‐pump beating heart CABG; ONCAB, on‐pump.

Figure 4

Ranking probability graph for 30‐day mortality. OPCAB has ~65% likelihood of being ranked the most effective revascularisation strategy, followed by OnBHCAB with a ~35% likelihood, then ONCAB with ~1% likelihood. OnBHCAB, On‐pump beating heart CABG; ONCAB, on‐pump CABG; OPCAB, Off‐pump CABG.