Asymmetric Braided Stent Wire Angles Radial Force
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Solution Overview
Problem
Braided stents face limitations in achieving high radial force on the vessel wall due to the use of thin wires, which compromises their ability to maintain fixation and expansion, especially when thin wires deform and twist, resulting in a lower restoring moment on the vessel wall.
Innovation Solution
The implementation of a rotationally symmetrical lattice structure with wire elements having different braiding angles and elastic properties, where one wire element has a smaller braiding angle and is more extensible, and the other has a larger braiding angle and greater compressibility, allowing for an asymmetrical configuration that enhances radial force by storing elastic energy through stretching and compressing the wires differently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If thin wires are used in braided stents to achieve flexibility and fine mesh, then the stent can be crimped with lower external force and maintain good flexibility, but the radial force exerted on the vessel wall is limited and the restoring moment is reduced
Solution Approach 1:
The patent applies asymmetry by introducing wire elements with different braiding angles (first angle α′ and second angle α″) relative to the axis of rotation. This asymmetric configuration creates differential elastic energy storage during expansion, where wires at different angles experience different deformation states, thereby generating enhanced radial force while maintaining flexibility.
Solution Approach 2:
The patent changes physical parameters by varying the braiding angles of different wire elements and utilizing their different elastic properties. This parameter variation allows the stent to optimize both flexibility (through thin wires with appropriate elastic properties) and radial force (through asymmetric angle configuration that maximizes restoring moment).
2Reliability
If thin wires are used to achieve a fine lattice structure, then plaque particle detachment risk is reduced and vessel growth is inhibited, but the radial force and fixing capability on the vessel wall are compromised
Solution Approach 1:
The asymmetric braiding configuration with different angles (α′ and α″) creates unequal deformation distribution among wire elements during stent expansion. This asymmetry maximizes the restoring moment generated by elastic energy storage in the thinner wires, thereby enhancing fixation capability while preserving the fine mesh structure that prevents plaque particle detachment.
Solution Approach 2:
The patent utilizes the curved, helical geometry of the braided wire structure with different pitch angles. This curvature configuration allows thin wires to generate effective radial force through elastic deformation during expansion, transforming the geometric arrangement into a force-generating mechanism that maintains both fine mesh and reliable fixation.
3Length of moving object
If the stent is compressed in the delivery system for delivery, then it can be inserted into small vessels, but the potential elastic energy stored is limited with thin wires, reducing the expanding force
Solution Approach 1:
The asymmetric braiding angles (α′ and α″) create differential elastic energy storage in different wire elements during compression and expansion. This asymmetry ensures that even with thin wires, the stent accumulates sufficient elastic energy through optimized geometric configuration, enabling effective expansion after delivery through small catheters.
Solution Approach 2:
The patent utilizes the three-dimensional helical geometry of the braided structure with varying pitch angles to maximize elastic energy storage. By optimizing the spatial arrangement and angles of wire elements in three dimensions, the stent achieves enhanced energy storage capacity within the constraints of thin wire diameter, enabling effective expansion force after compression delivery.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration achieves a high radial force for effective vessel wall fixation while maintaining flexibility and a fine mesh, enabling the stent to be crimped with lower external force and expanded to the desired diameter, reducing the risk of wire breakage and improving compressibility.
Implementation Method 1
the deformation force stored in the form of potential elastic energy being at its maximum
Implementation Method 2
The residual force with which the stent tries to return to the original diameter corresponds to the radial force of the meshwork acting on the vessel wall
Data Source
Figure 1
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Figure 2b
AI summary
The invention relates to a medical device comprising a rotationally symmetrical grid structure (10) having at least two spiral-shaped wire elements (11, 12) which are wound about a common axis of rotation R and which form a first and second intersection S', S", respectively, with a common plane L arranged perpendicularly to the axis of rotation, wherein a first straight line R' runs through the first intersection S' and a second straight line R" runs through the second intersection S". Said straight lines are each arranged parallel to the axis of rotation and include an acute angle (a', a") with one of the two wire elements (11, 12), respectively. The invention is characterized in that the two angles (a', a") are different and the wire elements (11, 12) have different elastic properties.