Preoperative B-Blockers as a coronary surgery quality metric: the lack of evidence of efficacy

Abstract Background Two quality measures used in public-reporting and value-based payment programs require β-blockers be administered Methods We conducted a systematic search for randomized controlled trials (RCTs) examining the impact of pre-operative β-blockers on AF or mortality following isolated CABG to determine what evidence of efficacy supports the measures. Results We identified 11 RCTs. All continued B-blockers post-operatively, making it unfeasible to separate the benefits of pre- vs post-operative administration. Meta-analysis was precluded by methodological variation in β-blocker utilized, timing and dosage, and supplemental and comparison treatments. Of the 8 comparisons of β-blockers/β-blocker+digoxin versus placebo (n=826 patients), 6 showed significant reductions in AF/supraventricular arrhythmias. Of the 3 comparisons (n=444) of β-blockers versus amiodarone, 2 found no significant difference in AF; the third showed significantly lower incidence with amiodarone. One RCT compared β-blocker+amiodarone versus each of those drugs separately; the combination reduced AF significantly better than the β-blocker alone, but not amiodarone alone. 7 RCTs reported short-term mortality, but this outcome was too rare and the sample sizes too small to provide any meaningful comparisons. Conclusions Existing RCT evidence does not support the structure of quality measures that require B-blocker administration specifically within 24 hours prior to CABG to prevent post-operative AF or short-term mortality. Quality measures should be revised to align with the evidence, and further studies conducted to determine optimal timing and method of prophylaxis.