Trends in the occurrence of new conduction abnormalities after transcatheter aortic valve implantation

OBJECTIVES: The aim of the study was to investigate trends over time in the occurrence of left bundle branch block (LBBB) and permanent pacemaker implantation (PPI) after transcatheter aortic valve implantation (TAVI) with the Medtronic CoreValve System (MCS) and Edwards SAPIEN Valve (ESV). BACKGROUND: TAVI-induced conduction abnormalities (TAVI-CAs) such as LBBB and the need for PPI are frequent postoperative complication. New techniques, procedural refinements, and increased awareness are focused on the reduction of these abnormalities. METHODS: Electrocardiograms of 549 patients without preprocedural LBBB and/or pacemaker were assessed to determine the frequency and nature of TAVI-CAs. To study the effect of experience, patients were subdivided per center into tertiles based on the number of procedures. Univariate and multivariate logistic regression was used to study predictors of TAVI-induced LBBB (TAVI-LBBB) and PPI. RESULTS: TAVI-LBBB occurred in 185 patients (33.7%) and significantly decreased over time, from 42.6% to 27.3% (P=0.006). This effect was only significant after implantation of the MCS (59.6% vs. 46.5% vs. 31.1%, P=0.001, ESV: 22.6% vs. 13.1% vs. 24.8%, P=0.11). Between tertiles there was no difference in the frequency of PPI after TAVI (n=73, 13.1% vs. 14.8% vs. 12%, P=0.74). Multivariate analysis revealed that, independent from valve type, depth of implantation was the only significant predictor of TAVI-LBBB (OR [95% C.I.]: 1.16 [1.10-1.24], P<0.001). In case of PPI pre-existing RBBB (OR [95% C.I.]: 7.22 [3.28-15.88], P<0.001) was the only significant predictor. CONCLUSIONS: Over time the frequency of LBBB after TAVI decreased significantly, especially in patients undergoing TAVI with the MCS. Experience and the subsequent reduction in depth of implantation seem responsible for this reduction. Contrary to TAVI-LBBB, the incidence of PPI remained unchanged over time and was not affected by experience. Although experience has led to a decrease in new CAs after TAVI, elucidation of pathophysiologic mechanisms underlying these CAs and subsequent changes in patient stratification, valve design and the procedure are needed to further reduce this complication.