Patient-specific coronary angioplasty simulations -- a mixed-dimensional finite element modeling approach

TL;DR

This paper introduces a mixed-dimensional finite element framework for patient-specific coronary angioplasty simulations, coupling a 1D beam-stent model with 3D artery and simplified balloon components via mortar and beam-to-solid contact. The approach enables efficient, realistic capture of stent deployment, balloon inflation, and post-procedural mechanical remodeling in both generic and patient-specific arteries. Key findings show high endothelial stresses near stenosis and stent boundaries during inflation, with persistent but diminished stresses after balloon withdrawal, suggesting potential mechanobiological drivers of ISR. The framework provides a foundation for objective, image-driven risk assessment across lesions and stenting scenarios, supporting future clinical studies and broader applications in slender biomechanical problems.

Abstract

Coronary angioplasty with stent implantation is the most frequently used interventional treatment for coronary artery disease. However, reocclusion within the stent, referred to as in-stent restenosis, occurs in up to 10% of lesions. It is widely accepted that mechanical loads on the vessel wall strongly affect adaptive and maladaptive mechanisms. Yet, the role of procedural and lesion-specific influence on restenosis risk remains understudied. Computational modeling of the stenting procedure can provide new mechanistic insights, such as local stresses, that play a significant role in tissue growth and remodeling. Previous simulation studies often featured simplified artery and stent geometries and cannot be applied to real-world examples. Realistic simulations were computationally expensive since they featured fully resolved stenting device models. The aim of this work is to develop and present a mixed-dimensional formulation to simulate the patient-specific stenting procedure with a reduced-dimensional beam model for the stent and 3D models for the artery. In addition to presenting the numerical approach, we apply it to realistic cases to study the intervention's mechanical effect on the artery and correlate the findings with potential high-risk locations for in-stent restenosis. We found that high artery wall stresses develop during the coronary intervention in severely stenosed areas and at the stent boundaries. Herewith, we lay the groundwork for further studies towards preventing in-stent restenosis after coronary angioplasty.

Figures (15)

• Figure 1: Artery macro- and microstructure
• Figure 2: Setup of artery, balloon, and stent; the fixation points are only free to move in the radial direction.
• Figure 3: Stent geometry; the stent struts are represented with their true thickness, though modeled as 1D beam elements
• Figure 4: Patient-specific artery geometry with lumen centerline, initial balloon and stent geometry
• Figure 5: Balloon diameter at different pressures for the generic free stent expansion simulation