Date of Award

8-9-2014

Document Type

Open Access Thesis

Department

Biomedical Engineering

First Advisor

Tarek Shazly

Abstract

Cardiovascular diseases are known to be one of the major causes of death around the world. One of the major causes of cardiovascular disease is arterial malfunction. Arteries malfunction when they experience chronic perturbations in their local environment above normal levels. Hence, we developed a bioreactor system in order to study the effect of chronic changes in the arterial global parameters (axial force, luminal pressure, and flow rate) on the behavior of local parameters (circumferential stress, axial stress, and flow induced shear stress). The bioreactor system was designed to (i) perform biaxial mechanical testing, (ii) incorporate, for the first time, the outer pressure as a fourth global parameter, (iii) independently control flow rate, transmural pressure (inner pressure minus outer pressure), and axial force, (iv) continuously monitor the change in arterial geometry, and (v) automatically reach/maintain constant level of user defined target values for mean axial and circumferential stress. The bioreactor system was capable of performing inflation Extension tests at axial stretch ratios of 1.2, 1.4, and 1.6 for a porcine renal artery at a pressure range from 10 to 180 mmHg. The bioreactor system was also capable of achieving target values of circumferential stress (5, 10, 15, and 20 kPa) with a tolerance of 10% at a constant level of axial stress (100 kPa) and vice versa; 60, 100, 140, and 180 kPa axial stress at constant circumferential stress of 5 kPa. A 95% Confidence Level was used to remove outliers form the collected data points.

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