Usefulness of membranous septum length in the prediction of major conduction disturbances in patients undergoing transcatheter aortic valve replacement with different devices

BACKGROUND Conduction disturbances (CD) are one of the most common adverse events after transcatheter aortic valve replacement (TAVR), and seem to be dependent on the device used as well as anatomical factors. AIMS The aim of this study was to evaluate whether the length of the membranous septum (MS) could provide useful information about the risk of CD and to examine the impact of the MS on CD after TAVR using different devices. METHODS This study included 140 patients undergoing TAVR with a balloon-expandable valve or self-expanding valve. The length of the MS was assessed by preoperative computed tomography. Delta MSID was calculated as the length of the MS minus implantation depth. RESULTS A total of 24 patients (17%) received a permanent pacemaker (PPM), 53 (38%) developed new-onset left bundle-branch block (LBBB) following TAVR. The MS length was shown to be the strongest independent predictor of new-onset LBBB (odds ratio [OR], 3.05; 95% CI, 1.96-4.77; P <0.001) and PPM implantation (OR, 3.76; 95% CI, 2.01-7.06; P <0.001). Delta MSID was also inversely associated with the development of LBBB and the need for PPM. In a head-to-head comparison, Delta MSID values were found to be statistically lower in the self-expanding valve group (-0.8 mm vs 0.7 mm; P <0.001). CONCLUSIONS A short MS and Delta MSID with a negative value increase the risk of CD. Assessment of the MS length prior to TAVR might serve as an additional tool to guide clinical decision-making and appropriate device selection to reduce the the risk of CD.