Date of Award

12-2011

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Mechanical Engineering

Advisor

Figliola, Richard S

Committee Member

Beasley , Donald E

Committee Member

Xuan , Xiangchun

Abstract

Every year many people suffer from severe chronic pulmonary insufficiency. Problems that can be incurred include the valve becoming stenotic, where it inhibits antegrade flow, and incompetent, allowing retrograde flow. When either of these conditions occurs with great severity, it is often necessary for the native valve to be replaced. There are no acceptable, permanent solutions currently available for a pulmonary valve replacement. Previous research, based on regurgitant fraction and transvalvular gradient, has indicated that a fluid diode could possibly serve as a permanent valve replacement solution. This study investigated the effectiveness of a diode to reduce the workload of a right ventricle while maintaining a tolerable regurgitant fraction and transvalvular pressure gradient. Three different diode geometries were compared to each other and also to a comparable stenosis and a blank annulus. The valve prototypes were tested in two positions in the mock pulmonary circulatory system (MPCS), immediately in the right ventricle outflow tract (RVOT) and also 3 cm downstream, in the pulmonary artery test section. The results of this study indicate that while all three of the diode designs performed very similarly to each other in each set of tests, the performance of the diodes varied greatly between the two positions in which they were tested. The diodes tested in the RVOT significantly reduced regurgitant fraction (RF), transvalvular gradient (TVG), and ventricular work as compared to the stenosis. However, the diodes demonstrated no significant reduction in TVG or ventricular work as compared to the stenosis or the blank annulus when placed within the pulmonary artery.

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