Segmented Stent for Fatigue Resistance in Pulsating Vessels
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Solution Overview
Problem
Conventional stents used in minimally invasive surgical procedures face premature failure due to cyclic stress from pulsating blood vessels, leading to potential injury and occlusion of interconnecting passages, especially when used between arteries and veins.
Innovation Solution
A stent design featuring two end portions with varying flexibility, where the intermediate portion is flexible to accommodate movement between the end portions, reducing stress and fatigue failure, and is made from a biocompatible polymer with embedded or external wire meshes for anchoring and support, allowing for differential expansion to maintain fluid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional stent is used to maintain fluid flow through blood vessels, then the stent can anchor securely and support the vessel wall, but the stent is subject to cyclic stress from pulsating vessels which leads to premature fatigue failure
Solution Approach 1:
The stent is divided into multiple segments or cells arranged in a pattern along its length. This segmentation allows each segment to move independently, accommodating the cyclic expansion and contraction of pulsating blood vessels without transmitting excessive stress throughout the entire structure, thereby reducing fatigue failure
Solution Approach 2:
The stent design incorporates variable parameters such as changing cell size, shape, or density along its length to optimize performance. By adjusting these parameters, the stent can provide enhanced flexibility in regions subject to high cyclic stress while maintaining structural integrity and anchoring capability in other regions
2Reliability
If the stent is made completely flexible to accommodate vessel movement, then fatigue failure is reduced, but the stent cannot anchor securely or maintain its shape to support the vessel wall
Solution Approach 1:
The stent is divided into multiple segments or cells arranged in a pattern along its length. This segmentation allows each segment to move independently, accommodating the cyclic expansion and contraction of pulsating blood vessels without transmitting excessive stress throughout the entire structure, thereby reducing fatigue failure
Solution Approach 2:
The stent design incorporates variable parameters such as changing cell size, shape, or density along its length to optimize performance. By adjusting these parameters, the stent can provide enhanced flexibility in regions subject to high cyclic stress while maintaining structural integrity and anchoring capability in other regions
3Stability of the object's composition
If the stent is made completely rigid to maintain its shape and anchor securely, then vessel wall support is improved, but the stent cannot accommodate movement between end portions leading to increased stress and fatigue failure
Solution Approach 1:
The stent is divided into multiple segments or cells arranged in a pattern along its length. This segmentation allows each segment to move independently, accommodating the cyclic expansion and contraction of pulsating blood vessels without transmitting excessive stress throughout the entire structure, thereby reducing fatigue failure
Solution Approach 2:
The stent design incorporates variable parameters such as changing cell size, shape, or density along its length to optimize performance. By adjusting these parameters, the stent can provide enhanced flexibility in regions subject to high cyclic stress while maintaining structural integrity and anchoring capability in other regions
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
The stent effectively maintains fluid flow between moving passages by reducing the likelihood of fatigue failure and anchoring securely within blood vessels, ensuring a stable pathway for blood flow, even under cyclic stress conditions.
Implementation Method 1
made from a biocompatible polymer with embedded or external wire meshes for anchoring and support
Implementation Method 2
intermediate portion is flexible to accommodate movement between the end portions, reducing stress and fatigue failure
Data Source
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AI summary
A device (10) for maintaining fluid flow through at least one passage in a human or animal body, the device comprising two end portions (12, 14) for anchoring the device in position, and an intermediate portion (16) which allows movement of the end portions relative to each another, wherein the end portions and intermediate portion together define a pathway for fluid flow through the device. The device is particularly suitable for use in the treatment of coronary heart disease by minimally invasive surgery, and the invention extends to a method for diverting fluid flow from one passage to another.