Structural design of a stent for a percutaneous aortic heart valve
Date
2009-03
Authors
Esterhuyse, Anton
Journal Title
Journal ISSN
Volume Title
Publisher
Stellenbosch : University of Stellenbosch
Abstract
Elderly patients suffering from aortic valvular dysfunction are often denied
aortic valve replacement due to the fact that they are classified as
too old and fragile to handle the physical stress of open-heart surgery
and cardio-pulmonary bypass. There exists a need for an alternative solution
which places less physical stress on the body. The development
of a percutaneous aortic heart valve (PAHV), which may be implanted
through a minimally invasive procedure, will provide a solution to old
and fragile patients who otherwise have a very limited life expectancy.
The development of such a device entails a costly and time-consuming
process which involves a number of phases, including a prototype development
phase, an in-vitro testing phase, an animal trial phase and a
human trial phase.
This thesis focuses on the design and analysis of the stent component
for a PAHV, suitable for implantation in sheep (animal trial phase). The
process of developing a first prototype, involved an analysis of the stent design requirements. This analysis was followed by a concept generation
phase as well as comprehensive finite element (FE) analyses of the most
promising concepts. The objective of the FE analyses was to determine
the effects of a variation in strut width on the performance characteristics
of the concepts. Based on the results of the FE analyses, final geometries
were selected for each of the two most promising concepts. Subsequent
to the selection of the final geometries, a number of prototypes were manufactured.
The prototypes were subjected to an electro-polishing process.
An experimental analysis was also conducted on the prototypes to evaluate
the accuracy of the (FE) simulations as well as the actual performance
of the stent prototypes.
The results of the FE analyses and experimental analyses indicated
that strut width had a substantial influence on the parameters that were
defined to characterise stent performance. The results of the analyses also
highlighted the advantages and disadvantages of each concept and aided
in identifying the concept that would be most suitable for the required
application.
Limitations of the study were identified and recommendations were
made to assist the continued research and development of the device.
Description
Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2009.
Keywords
Interventional cardiology, Dissertations -- Mechanical engineering, Theses -- Mechanical engineering