Impact of aortic valve leaflets calcium volume and distribution on Post-TAVR conduction abnormalities

Transcatheter aortic valve replacement (TAVR) is increasingly used to treat aortic stenosis, including in low-risk patients. However, post-procedural cardiac conduction abnormalities (CCA), often requiring permanent pacemaker implantation (PPI), remain a concern. This study investigates how the volume and distribution of aortic leaflet calcium deposits influence the risk of post-TAVR CCA.

An electromechanically coupled four-chamber beating heart model was used to simulate TAVR with a self-expandable Evolut® 26 mm device. Five virtual patient scenarios were modeled with varying calcium volumes and distributions: no calcium, uniform distribution (3 Calc), and isolated calcification on the left coronary leaflet (LCL), right coronary leaflet (RCL), or non-coronary leaflet (NCL). Electrical conduction was simulated using a monodomain model and coupled with structural mechanics to evaluate tissue-device interactions. Metrics included principal stress, contact pressure, and contact pressure index (CPI) over three cardiac cycles.

Larger calcium volumes and specific leaflet distributions increased stress and contact pressure near the atrioventricular node. The LCL model exhibited the highest mechanical stress and peak contact pressure (13.1 kPa), while the NCL model showed the lowest (6.42 kPa). The RCL model had intermediate values. Elevated contact pressure and stress in the LCL case suggest an increased risk of conduction disruption and PPI.

Leaflet calcium deposit volume and distribution significantly influence mechanical stress and contact dynamics near the conduction system following TAVR. These insights support the integration of clinical data, such as leaflet calcium volume and distribution into pre-procedural planning to personalize risk assessment and improve patient outcomes.