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Title: Pulsatile flow testing and development of prosthetic heart valves in conduits
Author: Leefe, Simon Edric
ISNI:       0000 0001 3607 6005
Awarding Body: Nottingham Trent University
Current Institution: Nottingham Trent University
Date of Award: 1991
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The work presented herein documents the development of a prototype valved conduit, building on previous work indicating that significant improvements in conduit haemodynamics were possible. Original contributions to this effort made by the author include an analysis of leakage data from which valve design guidelines are presented, the analysis of occluder instability during forward flow through an early prototype bail valve conduit and the development of an outlet profile to overcome this problem. The problem of performance evaluation is addressed. Since the fluid dynamical situation of a conduit-mounted valve differs from that for which a "hydraulic efficiency" or some similar performance indicator based on transvalvular pressure drop may be derived, an ideal orifice pressure drop does not represent a theoretical limit in conduit design. This consideration, together with the question of how to present data when the conduit is used as a second ventricular outflow tract prompts a rigorous enquiry into energy loss methods as an alternative criterion for conduit evaluation, demonstrating, for the first time, the particular suitability of this approach to valved conduits both as valvular replacements and, particularly, when used to provide a second ventricular outflow tract. It is demonstrated experimentally that the promising results of steady flow tests on the ball valve prototype may be realised under pulsatile flow conditions, for both modes of usage. The performance data are compared with those from a commercially available device in identical circumstances, constituting the first pulsatile test data for valved conduits.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Cardiac surgery