Finite element analysis of expandable bi-leaflet heart valves for infants

Abstract

The objective of this report is to highlight the various techniques utilised, improvements to existing designs, and results obtained in the finite element analysis of expandable bi-leaflet heart valves for paediatric patients in the pulmonary position. It is also intended to serve as a useful reference for the steps and thought processes involved in the modelling processes and in setting up and initiating the simulations. These considerations would be particularly useful for future students taking on this project as well as shed light onto the mechanics of bi-leaflet pulmonary valves under physiological loading. The computer-aided design software, Solidworks, was used to draw the heart valves and their surrounding conduits. These models were then exported to a finite element modelling software, ABAQUS CAE, to facilitate the study of their behaviour and performance under simulated physiological pulmonary pressure loading conditions. Some of the bi-leaflet heart valves that were attached to their respective conduits were modelled to simulate the growth of the right ventricular outflow tract of a paediatric patient. Upon completion of the finite element simulations for each bi-leaflet heart valve, the main performance parameters were analysed in greater detail. These parameters are namely the approximate percentage of regurgitation, maximum coaptation height, areas of maximum Von Mises stress and the coaptation areas over multiple cardiac cycles. Improvements on previous studies include finding and correcting errors in calculations and designs, testing the valve and conduit sizes that were previously not included in earlier studies and the establishment of a standard set of dimensions that can serve as a reference for all future studies. Other contributions include supporting the student participating in the experimental portion of this study by supplying the heart valve and conduit models completed on SolidWorks. Comparisons of the simulations results with experimental results were also considered but were unfortunately not obtainable due to issues faced by the student completing the experimental portion of this study.