Date of Award

8-1973

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Interdisciplinary Studies

First Advisor

Banyl N. Sauer

Second Advisor

Francis W. Cooke

Third Advisor

A. E. Schwartz

Abstract

Presently used prosthetic valves although capable of restoring the patient to a nearly normal life may cause significant hemodynamic complications, many of which are directly related to turbulent flow in and around the valve. The ultimate solution is to develop new prosthetic valve designs. However, the improvement of the flow characteristics of existing prosthetic valves using drag reducing polymers may offer a more immediate approach. To determine the effect of high molecular weight polymer additives on the hemodynamics of presently available prosthetic aortic heart valves, a steady-flow system utilizing a glycerine-water blood analog and an anatomically correct aortic valve test chamber was designed and fabricated. The effect of two synthetic polymers, polyarylamide, and polyetheylene oxide and one naturally occuring polysaccaride (Okra mucilage on the flow characteristics of five clinically used prosthetic valves and two experimental valves was studied. Pressure drop studies revealed that drag reduction within physiological flow rates was obtainable: that a 25-30% reduction in pressure drop was possible. Differences in the behavior of different polymer additives could be explained by consideration of current onset hypothesis. Polyethylene oxide at a concetration of 75 wppm was the best additive used in the study. Digital power spectral density analysis of distal was pressure fluctuations revealed that the effect of the polymer additives was to decrease the high frequency energy dissipation. Prothetic valves with central flow occluders dissipated more energy at higher frequencies than artifical valves of the full orifice type. The magnitude of the wall pressure fluctuations and the associated power spectral density was found to be a function of the prosethetic valve used, the flowrate, and the pressure tap location.

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