Utility of perioperative beta blocker therapy in patients undergoing cardiac surgery

Background Although there is abundant literature supporting the clinical utility of beta blocker initiation before non-cardiac surgery in high-risk patient populations, data supporting the routine initiation or continuation of beta blockers before and after cardiac surgery remains unclear. Purpose To perform a systematic review and meta-analysis evaluating the use of peri-operative beta-blockers in patients undergoing cardiac surgery and evaluate clinical outcomes such as rates of postoperative arrhythmias, cerebrovascular accidents (CVA), and in-hospital and all-cause mortality. Methods A literature search was performed using the databases PubMed, Embase, and Web of Science, identifying studies that evaluated the association of pre-operative initiation and continuation of beta-blocker with clinical endpoints in patients undergoing cardiac surgery. The endpoints of interest included development of post-operative atrial fibrillation (AFib), supraventricular tachycardia (SVT), in-hospital mortality, all-cause mortality, and CVA. Results 19 studies with 3749 patients (2018 treated with beta blockers, 1731 not treated with beta blockers) met inclusion criteria. The average follow-up duration was 12 days (ranging from 1 day to 90 days), the mean age was 63.4 years, 70% were men. Cardiac surgeries including coronary artery bypass grafting, aortic valve replacement, and mitral valve replacement. In patients undergoing cardiac surgery, perioperative use of beta blockers was associated with a significantly lower risk of post-op AFib (OR 0.49, 95% CI 0.31-0.78; P<0.01). Subgroup analysis shows this association was primarily with use of IV Landiolol and with a non-statistically significant trend toward lower risk of AFib in patients initiated or maintained on oral beta blockers (OR 0.29, 95% CI 0.20-0.41; p<0.01; OR 0.62, 95% CI 0.33-1.16; P=0.06). There was a statistically significantly lower risk of developing SVT after cardiac surgery in patients treated with beta-blockers (OR 0.45, 95% CI 0.24-0.86, P=0.02). The association between beta blocker use and other clinical endpoints including the risk of CVA, in-hospital mortality, and all-cause mortality were not statistically significant, however there was a trend toward lower risk of both in-hospital and all-cause mortality in patients who were treated with beta-blockers compared to those who were not (OR 0.46, 95% CI 0.16-1.36; P=0.16; OR 0.50, 95% CI 0.17-1.47; P=0.21). Discussion: This meta-analysis demonstrates that in patients who are undergoing cardiac surgery, preoperative initiation of beta-blockers, particularly IV Landilol, or continuation of chronic beta-blockers is associated with a lower risk of adverse cardiovascular outcomes, particularly post-operative AFib and SVT. The use of beta-blockers may also be associated with a mortality benefit, however additional high-quality studies with extended follow-up time and monitoring are needed to fully elucidate this association.