Patient-specific investigation into plaque rupture risk due to catheter tracking during TAVR

Abstract

Catheter delivery during transcatheter aortic valve replacement (TAVR) may result in plaque damage in patients with high plaque burden levels. Primarily, catheter tracking performance is measured through in-vitro methods, such as trackability testing, but these cannot account for the in vivo conditions that are dictated by anatomical variation and tissue properties. This study aims to apply patient-specific finite element (FE) modelling to investigate the potential stresses and contact pressures experienced in the aortic wall and by plaques during catheter tracking for TAVR delivery. This study utilised two patient-specific anatomies, derived from pre-TAVR CT imaging, to develop solid aorta and plaque models. A parameter study of plaque burden (low, moderate and high) and plaque stiffness (soft, intermediate and stiff) revealed a risk of plaque rupture only for one of the patients when they had a high plaque burden of intermediate stiffness. Highly stiff calcified nodules lead to very high plaque tissue stresses (6–9 MPa), but the rupture stress threshold for these plaque types remains unknown. We also observe no difference in catheter reaction forces between patients regardless of burden level or plaque stiffness, except for Patient 2's high plaque burden with stiff plaque variation.