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

Area of Science:

• Biomedical Engineering
• Cardiovascular Research
• Medical Imaging Analysis

Background:

• Catheter delivery in transcatheter aortic valve replacement (TAVR) poses risks of aortic plaque damage.
• Current in-vitro methods for assessing catheter trackability do not fully replicate in vivo conditions, including anatomical variations and tissue properties.

Purpose of the Study:

• To investigate potential stresses and contact pressures on the aortic wall and plaques during TAVR catheter delivery using patient-specific finite element (FE) modeling.
• To assess the impact of varying plaque burden and stiffness on these mechanical interactions.

Main Methods:

• Utilized patient-specific FE models of the aorta and plaques, derived from pre-TAVR CT imaging.
• Performed a parameter study varying plaque burden (low, moderate, high) and plaque stiffness (soft, intermediate, stiff).
• Analyzed catheter reaction forces and simulated stress/pressure distributions within the aortic wall and plaques.

Main Results:

• A risk of plaque rupture was identified in one patient with high plaque burden and intermediate stiffness.
• Highly stiff calcified nodules generated significant plaque tissue stresses (6-9 MPa), though rupture thresholds remain unknown.
• Catheter reaction forces showed no consistent difference across varying plaque burden or stiffness, except in one specific patient scenario (Patient 2, high burden, stiff plaque).

Conclusions:

• Patient-specific FE modeling is a valuable tool for assessing risks associated with TAVR catheter delivery.
• High plaque burden and intermediate stiffness present a potential risk for plaque rupture during TAVR.
• Further investigation into the rupture stress thresholds of different plaque types is crucial for improving TAVR safety.