Comparative Properties of Polymers Guiding the Development of an Abdominal Aorta Model

Hemodynamics, the study of the forces involved in the circulation of blood, is an area that researchers have approached in various manners for many years. The study of how blood flows through arteries and veins as well as the effect of the composition of the blood has been defined and thoroughly characterized in past studies. Although in-depth studies have been performed on the flow characteristics of blood, most often the observations are made as the fluid flows through tubes composed of some rigid material. It is well known that the arteries and veins have a layered histology that show varying viscoelastic characteristics. It is also accepted that the varying geometry of the vessel wall and the taper of the vessel have a significant effect on the flow characteristics of the vascular system. Therefore, a physical model of the vascular system that takes into account the elasticity and varying geometry of the blood vessel would prove extremely valuable in the hemodynamic study of the vascular system.

This study approached the task of determining the most suitable material to incorporate into a physical model of the abdominal aorta. The purpose of this study was to compare the mechanical properties of selected materials to those of canine blood vessels in order to choose which of these materials most accurately represents the viscoelasticity seen in large blood vessels such as the aorta. An in-depth approach to choosing a material with similar mechanical properties is defined. There is also a comparison of the time dependency of the vessel properties as well as the differences of the mechanical properties when the testing is performed in different directions.

The result of this study was the selection of a base material to which modifications will be made in the future to more accurately represent the mechanical properties of the abdominal aorta. It was determined that the time of storage and direction of testing had no effect on the properties demonstrated by the canine thoracic aortas and therefore did not effect the material selection process. The material selection process led to the conclusion that silicone rubber has the most similar mechanical properties to the blood vessels tested and therefore should be incorporated as the base material in a physical model of the abdominal aorta. The future of this study will include expanded testing that includes a broader range of materials and more in depth testing methods such as biaxial tensile tests and creep tests.