Mechanical Performance of Thoracic Aortic Stent-Grafts: An In Vitro and In Silico Study

Area of Science:

• Biomedical Engineering
• Computational Mechanics
• Cardiovascular Surgery

Background:

• Thoracic endovascular aortic repair (TEVAR) is a standard treatment for thoracic aortic diseases.
• The clinical success of TEVAR depends on the appropriate selection of stent-grafts (SGs).
• Understanding SG mechanical performance is crucial for optimizing TEVAR procedures.

Purpose of the Study:

• To comprehensively assess the mechanical performance of four commercial SGs under ideal and patient-specific conditions.
• To investigate the relationship between SG design, device-wall interaction, and biomechanical parameters.
• To evaluate the utility of computational simulations in pre-operative planning for TEVAR.

Main Methods:

• Development and validation of high-fidelity finite element models for SG deployment.
• Validation against experimental tests and in vitro TEVAR procedures using 3D-printed phantoms.
• Virtual deployment of SGs in patient-specific aortic models to analyze geometrical and mechanical interactions.

Main Results:

• Finite element models showed strong agreement with experimental data (average error < 5%).
• Increased metal density in SGs correlated with higher graft apposition (up to 94%) and radial forces (up to 354 N).
• Denser metal structures resulted in higher localized stresses (0.49 MPa vs 0.25 MPa), potentially improving fixation but risking vascular remodeling.

Conclusions:

• SG design critically influences TEVAR outcomes, affecting graft apposition, radial force, and stress distribution.
• Validated computational simulations can aid in pre-operative planning and personalized device selection for TEVAR.
• Optimizing SG selection based on patient anatomy is essential for mitigating procedural risks and improving long-term TEVAR success.