A Parameterized Cross-Sectional Model for Simulating Balloon Angioplasty in Atherosclerotic Arteries

Atherosclerotic arteries exhibit geometric alterations due to plaque deposition, which often leads to luminal narrowing. Balloon angioplasty is a common and suggested treatment to restore blood flow. However, depending on balloon oversizing, rupture at the plaque shoulder or the fibrous cap may occur. The rupture risk is influenced by factors such as the geometry of the fibrous cap, the lipid pool size, and calcifications. Despite advances in clinical imaging, predicting plaque rupture remains challenging because of lesion variability. This study addresses this gap by identifying key geometrical factors that influence stress distribution during balloon angioplasty, thus improving biomechanical insights and risk assessment. In this work, we develop a parameterized cross-sectional model of the atherosclerotic artery to investigate the influence of these components on stress distribution during balloon angioplasty. This model can be adapted to different stages and geometries of atherosclerosis. The parametric model enables the evaluation of the influence of uncertain input parameters, especially geometrical parameters, on the outcome of a finite element analysis. Experimental data from a layer-specific mechanical test on an iliac artery and pressure-diameter curves from balloon inflation tests are used to calibrate the respective constitutive models. Balloon angioplasty is then simulated by inflating a balloon in the narrowed artery without explicitly considering balloon unfolding. We perform $3000$ simulations for a local sensitivity analysis by varying the six most influential geometrical parameters and leaving the remaining parameters and the material parameters unchanged. The results show that the amount of the lipid pool has the largest influence on the maximum principal stress in the arterial tissue. Furthermore, the thickness of the fibrous cap plays a critical role in determining the specific location where this maximum occurs. These findings offer valuable insights into potential initiation sites of damage in atherosclerotic arteries.