Depth of implantation in relation to membranous septum as a predictor of conduction disturbances after transcatheter aortic valve implantation.

Background: Conduction disturbances remain one of the most common complications occurring post TAVI. We aim to determine the predictors of cardiac conduction disturbances after Transcatheter Aortic Valve Implantation (TAVI) and propose a relevant predictive model. We included 70 consecutive patients with severe symptomatic AS who underwent TAVI using the self-expanding valve Evolut R or the balloon expandable Sapien XT valve. All patients were subjected to electrocardiographic evaluation pre- and post-TAVI and at 30 days. Clinical, echocardiographic, CT-derived, and procedural parameters were collected and analyzed.

Results: Conduction disturbances affected 28 patients (40%): 16 patients (22.9 %) developed Left Bundle Branch Block (LBBB), 7 patients (10%) experienced transient Complete Heart Block (CHB), and 5 patients (7.1%) experienced permanent CHB requiring Permanent Pacemaker Implantation (PPI). We classified predictors into preprocedural and procedural predictors. Multivariate logistic regression analysis of pre-procedural predictors showed that the presence of basal septal calcification is the most powerful independent predictor (OR: 28.63, 95% CI: 4.59-178.68, p < 0.001). Multivariate logistic regression analysis for pre and post procedural predictors showed that the relationship between depth of implantation at the septum and membranous septum expressed in percentage (sDIMS) with cut-off >70.42% is the most powerful independent procedural predictor (OR: 1.11, 95% CI: 1.03-1.2, p 0.006).

Conclusion: Conduction disturbances remain a common complication of TAVI. Presence of basal septal calcification is a non-modifiable risk factor that increase patient propensity of development such complication after TAVI. A depth of implantation exceeding 70% of the membranous septal length has been found to strongly predict conduction disturbances post TAVI. sDIMS can be used in planning the depth of implantation to reduce incidence of conduction disturbances post TAVI.