Stented Prosthetic Heart Valve Uniform Stress Distribution
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Solution Overview
Problem
Current stented prosthetic heart valves experience uneven stress distribution and non-linear deflection due to their geometric design, leading to potential failure and difficulty in implantation, as they lack uniform rigidity and are prone to deformation under heart muscle action.
Innovation Solution
A stented prosthetic heart valve design featuring a stent post frame with a continuous, closed-curve shape and circumferentially spaced posts, where the cross-sectional shape is uniform and rotated 90 degrees at the tips, providing consistent bending inertia and rigidity, and mounting members secure the leaflets directly to the base frame through the stent post frame cloth covering, promoting linear deflection and reduced stress concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a devolved cylinder geometry is used for the stent post frame, then the stent can be manufactured using conventional methods, but the stress distribution becomes uneven and non-linear deflection occurs
Solution Approach 1:
The patent changes the geometric parameters of the stent post frame from a conventional devolved cylinder to a constant cross-section design with uniform thickness and rounded corners. This parameter change ensures uniform stress distribution while maintaining manufacturability through standard forming processes.
Solution Approach 2:
The patent introduces asymmetric rounding at the corners of the stent post frame cross-section. This asymmetric design with rounded corners eliminates stress concentration points that would otherwise occur at sharp angles, resulting in more uniform stress distribution throughout the structure.
2Ease of manufacture
If the stent post frame has varying cross-sectional geometry, then manufacturing is simplified, but the rigidity becomes non-uniform leading to deformation under heart muscle action
Solution Approach 1:
The patent employs a homogeneous cross-sectional geometry throughout the stent post frame, with constant thickness and uniform material distribution. This homogeneity ensures that the rigidity is uniform across the entire structure, preventing non-linear deflection and deformation under physiological loads.
3Ease of manufacture
If linear stent posts are used, then the structure is simple to manufacture, but stress concentration occurs at the tips leading to potential failure
Solution Approach 1:
The patent applies curvature by rounding the corners of the stent post frame cross-section. This spheroidal modification eliminates sharp angles that cause stress concentration, distributing stresses more evenly across the post tips and enhancing the overall strength and durability of the structure.
Data Source
AI summary
A stented prosthetic heart valve including a stent assembly, a leaflet assembly, and mounting members. The stent assembly includes a stent post frame, a stent post frame covering, and a base frame. The stent post frame includes a continuous rail forming a closed-curved shape defining a longitudinal axis, and a plurality of circumferentially-spaced posts projecting from cusp segments in a direction of the longitudinal axis. The cloth covering encompasses the rail. The base frame supports the cusp segments. The valve leaflet assembly is attached to the stent assembly, and includes a leaflet clamped between one of the cusp segments and the base frame. The mounting members each directly pass through the stent post frame cloth covering, the first leaflet and the base frame. The rail can have a constant cross-sectional shape with a major axis dimension that is greater than a minor axis dimension.