Abstract 4144490: Impact of Transient Conduction Disturbances on Long-term Outcomes Following Transcatheter Aortic Valve Implantation

Background: Conduction disturbances (CD) following transcatheter aortic valve implantation (TAVI) are well known as one of the important predictors of poor post-TAVI prognosis. Although persistent CD are evidently associated with poor prognosis, data on transient CD are limited. The aim of this study was to investigate the prognostic impact of transient CD on long-term clinical outcomes after TAVI. Methods: Patients with severe aortic stenosis (AS) undergoing TAVI between February 2017 and October 2022 were retrospectively enrolled. CD were defined as any of the following: 2nd- or 3rd-degree atrioventricular block, right or left bundle branch block, and intraventricular CD with QRS duration ≥120 ms. Transient CD were defined as CD that appeared after TAVI but improved either before discharge or within 7 days. Persistent CD were defined as CD that appeared after TAVI and presented at hospital discharge or >7 days after TAVI. The primary endpoint was cardiovascular adverse events (CAE) after discharge, defined as a composite of cardiovascular death, heart failure hospitalization, and new pacemaker implantation. Results: Of 412 enrolled patients, transient CD occurred in 81 patients (19.7%), persistent CD in 72 patients (17.5%), and no CD in 259 patients (62.9%). In comparison between the transient and no CD groups, membranous septum length was significantly shorter in the transient CD group (5.0 mm vs. 6.1 mm, p=0.005). For a maximum of 2,000 days follow-up (the median follow-up period was 569 days), the transient CD group showed a significantly higher incidence of CAE compared with the no CD group (18.5% vs. 9.3%, p=0.012) (Figure). Although there was no significant difference in cardiovascular mortality (11.1% vs. 8.5%, p=0.48), the incidence of heart failure hospitalization tended to be higher in the transient CD group (6.2% vs. 2.3%, p=0.091), and new pacemaker implantation was more frequent in the transient CD group (4.9% vs. 0.0%, p<0.001) compared with the no CD group. Conclusions: Post-TAVI transient CD were associated with a higher risk of long-term adverse events. Even though CD were transient and no longer present at discharge, careful outpatient follow-up may be necessary after TAVI.