Patient-specific Finite Element Model of Coronary Artery Stenting

Abstract

Background: Although several clinical and numerical studies have been conducted on plaque vulnerability assessment, it still remains a critical target for investigation. The stresses whether because of the blood pressure or stenting induce within plaque and arterial layers inside an atherosclerotic artery might exceed from their yield stresses and trigger plaque rupture or arterial layer injury. This study is aimed at conducting a comparative study to understand the vulnerability of the plaques, i.e., calcified, cellular, and hypocellular, as well as the coronary arterial layers, i.e., intima, media, and adventitia, during the stent expansion inside a patient-specific atherosclerotic coronary-artery model.

Methods: To do that, a three-dimensional (3D) finite element (FE) model of the atherosclerotic coronary artery is established on a basis of CT/MRI data of a patient. The stent is then expanded inside the atherosclerotic artery and the resulted stresses and strains in the plaque components, i.e., the fibrotic capsule (FC) and necrotic core (NC), and arterial layers are computed.

Results: The results revealed that the distribution and magnitude of the von Mises stresses in each component involved in stenting are different according to the plaque types and arterial layers. The stress in the calcified plaque is the highest as compared to the cellular and hypocellular. Lower stresses are observed in the adjacent medial and adventitial layers while the stress in the intima is high enough to invoke injury. The results suggest FC and plaque rupture may occur at localized regions as well as plaque shoulders. Eventually, the dogboning and foreshortening parameters found to be independent on that of the plaque types.

Conclusions: The results may have implications not only for understanding the vulnerable plaques and arterial layers to rupture during the stenting, but also for providing a comprehensive information for the medical and biomechanical experts in interventions and surgeries, including balloon-angioplasty, bypass, and stenting.

Keywords: Coronary stent; artery layers; atherosclerotic artery; balloon; finite element model; plaque..