| Summary: | Includes abstract. === Includes bibliographical references. === Aortic valve replacement in humans may be needed due to pathology leading to valve stenosis and regurgitation. Replacement is by either mechanical or soft tissue prosthetic valves. Before new valves are medically approved and introduced into the market they are required to undergo rigorous testing to verify performance and product life expectancy. Performance testing is done in a hydrodynamic test apparatus and life expectancy verified in an accelerated test apparatus. The Cardiology Department at Tygerberg Hospital has proposed a project for the design and implementation of a prosthetic aortic valve test apparatus. This device is to be used primarily for fatigue, but also limited hydrodynamic, testing of prosthetic heart valves. The design of the test apparatus was based on the four-element Windkessel model of the arterial system. This simple lumped parameter electrical analogy of the arterial system takes aortic and arterial resistance, arterial compliance, and blood inertance into account to simulate total arterial impedance. This model was developed with physiological reference and thus the element parameters only hold for physiological simulation as the equation governing impedance is speed sensitive. The model was adapted to provide theoretidal, physiological loads from physiological speeds of 60BPM through to accelerated speeds up to 1OOOBPM through mathematical optimisation of the Windkessel.The test apparatus was designed and built taking into account the varying Windkessel parameters where possible. Both compliance and resistance could be varied within an acceptable range, inertance however, could not be varied due to the limitations of the project. The apparatus was controlled and pressures on either side of the valve monitored with a LabView® graphical user interface. The apparatus was able to mimic in vivo closely and satisfied the ISO requirements for valve testing up to speeds of 230BPM. Various modifications are proposed to both the Windkessel model and the physical apparatus to compensate for hydrodynamic effects at high testing speeds in improve performance, as well as increase the maximum testing speed.
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