Date of Graduation

5-2019

Document Type

Thesis

Degree Name

Bachelor of Science in Biomedical Engineering

Degree Level

Undergraduate

Department

Biomedical Engineering

Advisor/Mentor

Jensen, Morten

Abstract

Malfunctioning venous cause issues ranging from cosmetic to life threatening situations for millions of people in the U.S. (1). Venous valve bioprosthetics often fail due to a loss in leaflet tissue flexibility following chemical fixation of donor tissue (2). A viable solution for testing venous valves prior to and post chemical fixation is in high demand for the development of a more durable prosthetic replacement. As a result, this research aims to create a fatigue apparatus that provides a means to model the durability of venous valves. The design criteria for this project included modeling physiological conditions in an accelerated time frame for fatigue. A big consideration was minimizing the allotted time for testing as much as possible. The completed apparatus can hold 5 vein segments at the same time in a clear acrylic chamber. A system of syringes with two linear actuators is used to propel the plungers to circulate saline solution through the valves. A preliminary test was run using this apparatus for 10 hours with 4 valves. Uniaxial mechanical testing was completed, however the condition of the leaflets upon harvest was very poor due to holes and they varied in size. Stress strain curves were plotted for 5 leaflet samples and the results of the peak tangent moduli made it evident the valves would need to be placed in the apparatus for longer than 10 hours. The preliminary testing made it evident that valves would need to be removed from sample data if they are found defective prior to fatiguing. The built apparatus meets all the design criteria and can model 1 year of valve life in 2.6 days. Further work is needed in the form of biaxial testing with comparisons of mechanics made among fresh, fatigued, and chemically fixated valves.

Keywords

venous valves; fatigue; cardiovascular

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