Document Type : Full Research Paper

Authors

• Faeze Jahani ¹
• Malikeh Nabaei ¹
• Zhenxiang Jiang ²
• Seungik Baek ²

¹ Biological Fluid Dynamics Research Laboratory, Department of Biomedical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran

² Cardiovascular and Tissue Mechanics Research Laboratory, Department of Mechanical Engineering, Michigan State University, East Lansing, MI, USA

Abstract

An abdominal aortic aneurysm is a gradual enlargement of the diameter of the aorta, which can threaten the patient's life if it ruptures. Several factors are effective in reducing aneurysm rupture risk and behavior. One of the important factors is the geometric characteristics of the aneurysm. It is necessary to examine the geometric characteristics (shape and maximum diameter) of abdominal aortic aneurysms for each patient to predict the risk of aneurysm rupture and its behavior. Growth and remodeling models based on the finite element method are tools for describing biological characteristics and predicting the progression of diseases such as abdominal aortic aneurysms. In this article, a stress-mediated growth and remodeling model was used to simulate different geometries of abdominal aortic aneurysms with the help of elastin damage function and collagen turnover. The simulation results emphasized the role of elastin damage on the geometrical changes of the aneurysm and the sensitivity of collagen turnover on wall stress distribution and expansion rate, so that with the change of the collagen rate from 0.07 to 0.04, the wall stress increased up to 300 kPa. The results showed that the stress distribution and local expansion correspond to the amount of elastin damage. The elastin damage function plays a key role in determining the location of the maximum diameter and in creating different forms of abdominal aortic aneurysms. Furthermore, time changes have a direct impact on elastin degradation. The remodeling of collagen, which was caused by increasing stress, compensated for the loss of elastin and controlled the expansion rate of the aneurysm. In the future, this computational model will have the ability to depict patient-specific abdominal aortic aneurysm growth with the help of the geometrical changes of the aneurysm, the amount of elastin damage, and collagen remodeling.

Keywords

• Growth and remodeling computational model
• Damage function of elastin
• Collagen turnover
• Aneurysm growth

Main Subjects

• Computational Biomechanics