Predictors of Cardiac Conduction Disturbances After Transcatheter Aortic Valve Implantation Using Selfexpandable Valves

Background: The advent of transcatheter aortic valve implantation (TAVI) represented a paradigm shift for treating patients with severe symptomatic aortic stenosis (AS) who are at high or prohibitive surgical risk. With the growing experience in this field, the rate of periprocedural complications has decreased over time and TAVI has been increasingly performed with a minimalist approach, evolving into a safe procedure with predictable outcomes. However, unlike other procedural complications, the incidence of conduction disturbances which could be in the form of bundle branch blocks, oratrioventricular blocks, has failed to decrease in recent times, with reports suggesting an increased risk associated with the use of some newer-generation transcatheter valves. Aim of the work: To determine the predictors of cardiacconduction disturbances after transcatheter aortic valve implantation. Patients and Methods: From January 2017 to April 2019, we included 38 consecutive patients with severe symptomatic AS underwent TAVI using self-expandable valves (CoreValve or Evolut R) or the balloon expandable Sapien XT valve at the Ain Shams University Hospitals. All patients were subjected to electrocardiographic evaluation pre- and post-TAVI and at 30 days. Several parameters were studied including preprocedural parameters: clinical, electrocardiographic, echocardiographic, and CT derived parameters, and procedural parameters: type and size of the valve, the use of balloon pre- and post- implantation dilatation, and depth ofimplantation. All quantitative parameters were indexed to body surface area (BSA). Results: Conduction disturbances were seen in 16 patients (42.1%), in which 10 patients (26.3%) experienced left bundle branch block (LBBB), 6 patients (15.8%) experienced complete heart block (CHB), with only one of them (2.6%) experienced permanent CHB requiring permanent pacemaker implantation (PPI). Multivariate logistic regression analysis for pre-procedural predictors showed that the presence of basal septal calcification is the most powerful independent predictor (OR: 98.73, 95% CI: 7.63 to 1278.23, p < 0.001). Multivariate logistic regression analysis for procedural predictors showed that the relationship between depth of implantation and membranous septum expressed in percentage (DIMS) with cut-off >75.00% is the most powerful independent procedural predictor (OR:16.00, 95% CI: 2.12 to 120.65, p 0.007). Conclusion: Conduction disturbances remain a common complication of TAVI. Presence of basal septal calcification is a risk factor that increase patient propensity for developing such complication after TAVI. The relationship between depth of implantation and membranous septum is a strong independent procedural predictor and prospective validation of its cut-offs is needed.