As the most commonly diseased valve of the heart, the mitral valve has been the subject of extensive research for many years. Prior research has focused on the development of surgical repair techniques and mainly consists of in vivo clinical studies into the efficacy and long-term effects of different procedures. There is a need for a means of studying the mitral valve ex vivo, incorporating patient data and the effects of different repair techniques on the valve prior to surgery. In this study, a method was developed for reconstructing the mitral valve from patient-specific data. Three-dimensional transthoracic and transesophageal echocardiography (3D-TTE and 3D-TEE) were used to obtain ultrasound images from a normal subject and a patient with mitral valve regurgitation. Geometric information was extracted from the images defining the primary structures of the mitral valve and a special program in MATLAB was created to automatically construct a finite element model of a valve. A dynamic finite element analysis solver, LS-DYNA 971, was used to simulate the dynamics of the valves and the non-linear, anisotropic behaviour of biological tissue. The two models were successful in simulating the dynamics of the mitral valve, with the subject model displaying normal function and the patient model showing the dysfunction displayed in the ultrasound images. A method was then developed to modify the original patient model, in a way that maintains its patient-specific nature, to model mitral valve repair. Four mitral valve repair techniques were simulated using the patient model: the annuloplasty ring, the double-orifice Alfieri stitch, the paracommissural Alfieri stitch, and the quadrangular resection. The former was coupled with the other three techniques, as is standard protocol in mitral valve repair. The effects of these techniques on the mitral valve were successfully determined, with varying degrees of improvement in valve function.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:OOU-OLD./22876 |
| Date | 28 May 2012 |
| Creators | Baxter, Iain A. |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Thèse / Thesis |
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