Objectives: To assess the risk of conduction system abnormalities requiring permanent pacemaker (PPM) implantation following transcatheter aortic valve implantation (TAVI) with balloon expandable valve.
Background: The membranous septum (MS) length serves as an anatomic surrogate of the distance between aortic annulus and bundle of His and thus may shows an inverse relation to risk of conduction system abnormalities.
Methods: Fifty two consecutive patients (80.6 ± 7.4 years) with symptomatic severe aortic stenosis underwent a native and contrast-enhanced 256-slice computed tomography (CT) with iterative reconstruction technique before TAVI. The contrast-enhanced CT-data was reconstructed at 10% increments of the RR-interval and the (non-reformatted) standard coronal view in the systolic phase (40% of RR interval) was used for MS length was measurement.
Results: Eighteen patients (35%) required PPM implantation after the procedure due to high degree atrioventricular block (n = 12), new-onset bundle branch block with PR prolongation (n = 3), and slow atrial fibrillation (n = 3). Pre-procedural multivariable logistic regression model revealed MS length as the most powerful independent predictors of PPM implantation with an odds ratio of 1.3 (CI: 1.04 - 1.62; P = 0.02). In the post-procedural analysis MS length minus implantation depth was the most powerful independent predictors of PPM implantation in patients undergoing TAVI with an odds ratio of 1.33 (CI: 1.6 - 1.12; P = 0.001).
Conclusion: MS length as assessed by CT imaging is the most powerful pre-procedural predictor for pacemaker following TAVI, while the difference between MS length and implantation depth is the most powerful post-procedural predictor as well as the most powerful independent predictor in general.
