Conduction disorders after transcatheter aortic valve implantation: association with long-term outcome
Authors: Chua A P A , Myagmardorj R , Nabeta T , Kuneman J H , Van Der Kley F , Bax J J , Ajmone Marsan N 
Published: November 2023

Abstract

Background
As the indications for Transcatheter Aortic Valve Implantation (TAVI) are expanding, the long term consequences of its potential complications, such as the development of new left bundle branch block (LBBB) or the need for permanent pacemaker (PPM) implantation, are of increasing clinical importance. Studies on the prognostic impact of conduction disorders after TAVI showed conflicting results, and data after the first year are limited.

Purpose
To examine the progression of significant conduction abnormalities (CA) within the first year after TAVI, and investigate the long-term outcome of PPM implantation and permanent LBBB beyond the first year.

Methods
Patients who underwent TAVI between 2007-2019 and who had at least 1 year follow-up were included, and divided into 3 groups: 1)PPM implantation within the first year, 2)development of LBBB persisting until 1 year (permanent LBBB), and 3)no CA. Twelve-lead electrocardiograms (ECG) were collected at baseline, post-TAVI, and at 1 year. The primary end-point was all-cause mortality.

Results
Among 794 patients, 502 who underwent TAVI without baseline CA were divided into those with PPM(n=89), permanent LBBB(n=56), and no CA(n=357). Baseline clinical characteristics did not significantly differ, except for the self-expanding valve, which was more common among the PPM group (40% vs 25% in LBBB and 15% in no CA, p&lt;0.001). Baseline echocardiographic parameters were also comparable. The PPM group showed more frequent first degree AV block and right bundle branch block, as well as longer PR and QRS intervals, on pre-TAVI ECG. Immediately post TAVI, 32% of patients developed new LBBB, but only 19% persisted until discharge, and 11% at 1 year (Figure 1). Meanwhile, 18% needed a PPM within the first year, with a median time of 4 days. At 1-year follow up, overall improvement in NYHA class was observed but significantly more patients remained in NYHA class III-IV among the LBBB group (11% vs 6% in PPM and 3% in no CA, p=0.039). At 1 year, echocardiographic parameters showed significant differences, with lower left ventricular ejection fraction and global longitudinal strain (GLS) in the PPM and LBBB group compared to the no CA group (55±9% and 15±4% vs. 54±11% and 15±4% vs. 58±9% and 17±4% respectively, p&lt;0.001). Beyond 1 year, survival analysis showed a significant difference in all-cause mortality (2= 10.168, p=0.006) between PPM and no CA group (p=0.001, Figure 2) during a median follow-up of 49 months [IQR 34-74 months]. Multivariable Cox regression showed that PPM implantation (HR 1.654, p=0.011), baseline EuroSCORE II (HR 1.072, p=0.002), NYHA III-IV at 1 year (HR 4.432, p=&lt;0.001) and GLS at 1 year (HR 0.950, p=0.027) were independently associated with outcomes.

Conclusion
Post-TAVI conduction disorders are dynamic until 1 year follow-up and patients who needed a PPM implantation showed worse long term outcomes. Therefore, adequate follow-up after TAVI is of paramount importance.Progression of LBBB and PPM after TAVRKaplan Meier Survival Analysis