Effect Of Pre-Existing Left Bundle Branch Block On Post-Procedural Outcomes Of Transcatheter Aortic Valve Replacement: A Meta-Analysis Of Comparative Studies

Background: As an established procedure for patients with aortic valve stenosis and a high surgical risk profile, transcatheter aortic valve replacement (TAVR) can be associated with conductance abnormalities. However, data regarding the impact of pre-existing left bundle branch block (LBBB) on post-TAVR outcome is scarce. Objectives: We conducted this meta-analysis to pool available data in the literature on the impact of pre-existing LBBB on the clinical outcomes of patients undergoing TAVR. Methods: We queried Medline/PubMed, Scopus, and Cochrane Library to identify comparative studies of patients with and without a pre-existing LBBB undergoing TAVR for aortic stenosis. Risk ratio (RR) and the corresponding 95% confidence interval (95% CI) were estimated to measure the effect of pre-existing LBBB on developing post-procedure stroke, permanent pacemaker implantation (PPM), or moderate/severe aortic regurgitation (AR). Results: Data of three clinical trials encompassing 4,668 patients undergoing TAVR were included in this meta-analysis. Patients with pre existing LBBB prior to TAVR had an increased risk of developing moderate/severe AR (RR = 1.04 [0.79 1.37]; P = 0.77), stroke (RR = 1.72 [0.61-4.85]; P = 0.31), and a need for PPM implantation (RR = 4.43 [0.43-45.64]; P = 0.21) following TAVR. Conclusion: Preexisting LBBB seems to increase the risk of developing stroke, aortic regurgitation, and the need for a permanent pacemaker implantation. However, due to scarcity of data and high heterogeneity among the current studies, further clinical trials are warranted.