Cardiovascular Biomechanics
Sara Barati; Nasser Fatouraee; Malikeh Nabaei
Volume 15, Issue 4 , March 2022, , Pages 355-366
Abstract
Transcatheter aortic valves have become the standard procedure for high-risk patients with severe aortic valve stenosis. This minimally invasive procedure can expand to a wider range of patients with a lower risk of surgery. The complications after the implantation and the structural malfunction of these ...
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Transcatheter aortic valves have become the standard procedure for high-risk patients with severe aortic valve stenosis. This minimally invasive procedure can expand to a wider range of patients with a lower risk of surgery. The complications after the implantation and the structural malfunction of these prostheses are the obstacles of this transition. Design optimization of the stents of these prostheses can improve their performance and reduce the post-operative complications associated with them. Since all prostheses are crimped before implantation, the designs should guarantee an acceptable structural performance after expansion, especially self-expandable stents for which the fatigue behavior strongly depends on the strain. This study applies a simple, cost-effective optimization framework to optimize the geometric parameters of these stents regarding the maximum strain during the crimping process. The design parameters include diameter profile, cell size, number of repeating components, and strut cross-section. The simplified models are evaluated and verified by the 3D simulations. The results show that the middle cells' height, number of cells, and strut width have the most prominent effect on the maximum crimping strain of the stent. The maximum strain of the optimized stent in the selected design space was 0.52. This stent had a width of 0.2 mm, thickness of 0.3 mm, the number of cells and patterns of 3 and 15, respectively, and the diameter profile associated with the diameter ratio of 1.05. This framework can be applied to a wide range of stent designs and tremendously reduce the cost of stent design and optimization.
