Transcatheter aortic valve replacement (TAVR) has expanded to a well-established treatment strategy in patients with severe symptomatic aortic stenosis at increased surgical risk. The new-onset of electrical conduction disturbances remains one of the most frequent adverse events of the procedure with possible impact on prognosis. LBBB can lead to heart failure and pacemaker dependency, but LBBB after TAVR is often transient and conduction defects may improve over time.

 

This single-centre observational study aimed to investigate the incidence of new-onset LBBB after TAVR and to evaluate predictive factors for LBBB persistence during follow-up.

 

Methods: 

From January 2014 to August 2021, TAVR was performed in a total of 2794 patients at our institution. All patients underwent multi-slice computed tomography before TAVR. Patients with new-onset LBBB were included in the final analysis if they completed follow-up examination during the first year after TAVR with clinical visit und 12-lead electrocardiography for evaluation of LBBB persistence or recovery. To obtain the significant predictors of LBBB persistence after TAVR we used multivariate logistic regression analysis.

 

Among 2794 patients undergoing TAVR (age 79.3 ± 6.8 years, 55.4% female, STS Score 4.8 ± 4.3%), 448 patients (16.0%) showed new-onset LBBB in electrocardiogram before hospital discharge. These patients had an average age of 79.3 years with balanced gender distribution (55.4% female) and increased surgical risk (STS Score 4.8 ± 4.3%). 185 of the 448 patients with new-onset LBBB completed a follow-up examination with spontaneous LBBB recovery in 82 patients (44.3%). Pre-existing diabetes mellitus (43.7% vs. 24.4%; p=0.006) and prior atrial fibrillation (51.5% vs. 26.8%; p<0.001) were more often in patients with LBBB persistence. Furthermore, patients with persisting LBBB had larger valve anatomy regarding aortic annulus perimeter (78.4 ± 7.8 mm vs. 76.4 ± 8.4 mm; p=0.062) and left ventricular outflow tract perimeter (77.4 ± 8.8 mm vs. 74.3 ± 9.0 mm; p=0.011). In patients with LBBB persistence, procedural differences turned out to be a deeper implantation depth measured below the left coronary cusp (6.1 ± 2.4 mm vs. 5.1 ± 2.7 mm; p=0.007), a smaller mean difference between implantation depth and the membranous septum length (MSL) (2.2 ± 3.5 mm vs. 3.3 ± 3.0 mm; p=0.037), and higher incidence of resheathing during implantation process (25.2% vs. 14.5%, p=0.07). A multivariate regression model demonstrated a significant associations of pre-existing diabetes mellitus (p=0.02), prior atrial fibrillation (p<0.001), and the difference between implantation depth and MSL (p=0.009) with LBBB persistence after TAVR. There was no difference in outcome between the both groups of patients with LBBB persistence and recovery regarding mortality, rehospitalization or progression to advanced conduction defects with need for pacemaker implantation (8.7% vs. 4.9%; p=0.327).

 

In summary, new-onset LBBB occurred in 16% of patients after TAVR and resolved spontaneously in about half of the cases (44.3%) during follow-up. Recognition of the adverse effects of new-onset LBBB following TAVR could lead to the development of new strategies that may enhance clinical outcomes.