Aortic and arterial mechanics

TL;DR

This paper reviews the mechanical properties of the aorta, including elasticity and rupture strength, and discusses how these properties are measured, modeled, and altered in disease, with a focus on predictive simulations for personalized treatment.

Contribution

It provides a comprehensive overview of aortic biomechanics, highlighting recent advances in measurement, modeling, and the implications for treating aortic diseases.

Findings

Elastic modulus in the circumferential direction is key for aortic elasticity.

Tensile strength in the thoracic aorta is about 1.5 MPa, radial strength about 0.1 MPa.

Mechanical properties vary spatially and change with disease progression.

Abstract

Knowledge of the mechanical properties of the aorta is essential as important concerns regarding the treatment of aortic pathologies, such as atherosclerosis, aneurysms and dissections, are fundamentally mechanobiological. A comprehensive review is presented in the current chapter. As the function of arteries is to carry blood to the peripheral organs, the main biomechanical properties of interest are elasticity and rupture properties. Regarding elastic properties, an essential parameter remains the physiological linearized elastic modulus in the circumferential direction, although sophisticated constitutive equations including hyperelasticity are available to model the complex coupled roles played by collagen, elastin and smooth muscle cells in the mechanics of the aorta. Regarding rupture properties, tensile strengths in the axial and circumferential directions are on the order of 1.5 MPa in the thoracic aorta and the radial strength, which is important regarding dissections, is about 0.1 MPa. All these properties may vary spatially and change with the adaptation of the aortic wall to different conditions through growth and remodelling. The progression of diseases, such as aneurysms and atherosclerosis, also manifests with alterations of these material properties. After presenting how the mechanical properties of elastic arteries, including the aorta, can be measured and how they can be used in models to predict the biomechanical response of same under different circumstances, a section will focus on the biomechanics of the ascending thoracic aorta and the chapter will end with current challenges regarding predictive numerical simulations for personalized medicine.