Predictive Value of the Implantation Depth–to–Membranous Septum Ratio (DIMS) for Conduction Disturbances Following Transcatheter Aortic Valve Replacement: Development of a Hypothesis-Generating Risk Model

Abstract

Objective: Conduction disturbances remain a common complication following transcatheter aortic valve replacement (TAVR), particularly with self-expanding valve systems. This study aimed to evaluate the association between the implantation depth–to–membranous septum ratio (DIMS) and the occurrence of new-onset conduction disturbances, and to develop a hypothesis-generating risk model in patients undergoing TAVR with repositionable self-expanding valves. Methods: In this prospective observational study, 74 patients with severe symptomatic aortic stenosis undergoing TAVR were included. The primary endpoint was the occurrence of new-onset conduction disturbances within 30 days, defined as a composite of atrioventricular block, new left bundle branch block (LBBB), or PR interval prolongation. Multivariable logistic regression analysis was performed to identify independent predictors. A predictive model was constructed using significant variables and internally validated using bootstrap resampling techniques. Results: Conduction disturbances occurred in 25.6% of patients, with 17.5% classified as persistent. The DIMS ratio was independently associated with post-TAVR conduction disturbances. When combined with baseline QRS duration and aortic angulation, the predictive model demonstrated moderate discriminative ability (AUC 0.78). A hypothesis-generating risk score incorporating these variables showed high specificity but limited sensitivity. Predictive performance should be interpreted cautiously due to the limited number of outcome events and absence of external validation. Conclusion: The DIMS ratio is associated with conduction disturbances following TAVR using repositionable self-expanding valves. Integration of anatomical and electrocardiographic parameters may enhance risk stratification; however, these findings are exploratory and require validation in larger, multicenter cohorts before clinical application.