Impact of Aortic Valve Leaflets Calcium Volume and Distribution on Post-TAVR Conduction Abnormalities

Introduction

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.

Methods

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.

Results

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.

Conclusion

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.

Highlights

• Beating heart model used to assess post-TAVR conduction abnormality risk.

• Higher calcium volume increases contact pressure near conduction pathways.

• Left coronary leaflet calcification linked to elevated post-TAVR CCA risk.

• Dynamic simulations show stress fluctuations during cardiac cycles.

• Findings support personalized TAVR planning to reduce PPI need.