Left ventricular outflow tract eccentricity and the aortic annulus perimeter are strong predictors of permanent pacemaker implantation after self-expandable TAVR insertion
Authors: Romero Otero J M , Franco Pelaez J U A N A , Pinero Lozano A , Ibanez Cabeza B O R J A , Avila Barahona P A L O M A , Lopez Orosa J O R G E , Perona Miguez D A N I E L , Sanchez Gonzalez J C , Castillo Marin M A R , Rodriguez Lopez C A R L O S , Esteban Chapel J A , Pello Lazaro A M , Tomas Mallebrera M A R T A , Navarro Del Amo F E L I P E , Tunon Fernandez J O S E 
Published: November 2023

Abstract

Introduction
Transcatheter aortic valve replacement (TAVR) has become the treatment of choice for many patients with degenerative aortic stenosis. Nevertheless, need for permanent pacemaker implantation (PPI) continues being the Achilles heel after TAVR, especially for self-expanding valves. On the other hand, computed tomography (CT) scan provides several measurements with paramount importance for the success of the procedure. The aim of our study was to investigate whether CT-scan could help to identify patients at high risk for PPI need after TAVR.

Methods
We included all consecutive patients who underwent successful TAVR in a single center, since 2018 to 2022. Patients with previous PPI, "valve in valve" procedures, or without CT-scan measures of interest were excluded. Patients were followed-up at least 30 days after index procedure. Clinical, electrocardiographic and procedural characteristics were recorded, as well as CT-scan variables, such as annulus and left ventricle outflow tract (LVOT) perimeter and major and minor axis of both. Eccentricity index (EI) was calculated using the formula for the ellipse (the square root of 1-(minor axis/major axis)2), where the closer to 0 means more circular and the closer to 1 more eccentric ellipse. Multivariate binary logistic regression, including known clinical and electrocardiographic predictors of PPI after TAVR, along with CT-scan measurements, was done searching for the model best predicting PPI-need 30 days after TAVR.

Results
From the 297 patients undergoing TAVR in our centre during the study period, 106 were excluded because they met one of the excluding criteria (64 because of the lack of complete CT-scan data). Thus, 191 patients form the study population. 40 patients (20.9%) required a PPI. Characteristics of patients with/out PPI are shown at Table 1. After multivariate regression analysis, the best model predicting PPI included pre-existing complete right bundle branch block (RBBB) (HR: 3.86; 95%CI [1.35-11.02], p=0.013), larger valve size (HR (29-34 mm vs. 23-26 mm): 3.00; 95%CI [1.34-6.75], p=0.006) and LVOT EI (HR for every increase in 0.01: 0.96; 95%CI [0.94-0.99], p=0.021). C-statistic of the model was estimated in 0.762 (95%CI [0.677-0.847], p&lt;0.001). ROC curve obtained with the model is shown at Figure 1.

Conclusions
Previous CT-scan measurements may help to identify patients at high risk for PPI after self-expanding TAVR. In our series, the strongest predictors for PPI were RBBB, LVOT EI (the lower the eccentricity, the higher the risk) and use of larger prostheses size (29 and 34 mm), which may be considered as a surrogate of the annular perimeter obtained by CT-scan.Baseline characteristicsROC curve