Stent with Offset Connecting Elements for 3D Vessel Curvature
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Solution Overview
Problem
Existing stents fail to effectively accommodate the three-dimensional curvature of blood vessels under loading conditions, leading to stress concentration and potential vascular diseases such as thrombosis and intimal hyperplasia.
Innovation Solution
A stent designed to expand from a delivery configuration to a deployment configuration, where it transitions from an unloaded, straight or two-dimensionally curved state to a loaded, three-dimensionally curved state, utilizing a biased structure with offset connecting elements to maximize fracture resistance and minimize stress points, and induce a swirling blood flow pattern that inhibits vascular diseases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a stent is designed with a straight or two-dimensionally curved configuration in the unloaded state, then it is easier to deliver through the vasculature, but it cannot effectively accommodate three-dimensional curvature of blood vessels under loading conditions
Solution Approach 1:
The stent is designed with dynamic geometric transformation capability, transitioning from a straight or two-dimensionally curved configuration in the unloaded state to a three-dimensionally curved configuration under compressive loading. This dynamic adaptation allows the stent to maintain ease of delivery while effectively accommodating the three-dimensional curvature of blood vessels during normal physiological loading conditions.
Solution Approach 2:
The stent structure incorporates elements that enable transformation from two-dimensional curvature in the unloaded state to three-dimensional curvature under load. The connecting elements and annular elements are configured to twist and rotate, adding a third dimensional component to the curvature, thereby allowing the stent to match the complex three-dimensional geometry of tortuous blood vessels while maintaining deliverability.
2Strength
If a stent is designed to be rigid to provide structural support, then it resists compression forces, but it creates stress concentration points and cannot accommodate vessel deformations
Solution Approach 1:
The stent incorporates regions of varying stiffness through its annular elements and connecting elements. The annular elements provide localized radial strength to resist compression forces, while the connecting elements are designed with lower stiffness to allow geometric transformation and accommodate vessel deformations. This local differentiation of mechanical properties allows the stent to maintain overall structural support while avoiding stress concentration at specific points.
3Force
If a stent is designed with high radial strength to resist compression, then it maintains vessel patency, but it promotes thrombosis and intimalhyperplasia due to stress concentration
Solution Approach 1:
The stent's geometric configuration dynamically adapts under compressive loading, transforming from a straight or two-dimensionally curved state to a three-dimensionally curved state that matches the natural geometry of the blood vessel. This dynamic adaptation distributes radial forces more evenly along the stent-vessel interface, maintaining adequate radial strength to prevent vessel collapse while eliminating stress concentration points that would otherwise promote thrombosis and intimalhyperplasia.
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 accommodates blood vessel deformations, reduces thrombosis and platelet adhesion, and prevents intimal hyperplasia by imposing a three-dimensional curvature that promotes a swirling blood flow, enhancing fracture resistance and inhibiting vascular diseases.
Implementation Method 1
the stent is expandable from a delivery configuration to a deployment configuration, wherein upon application of a load to the stent when the stent is in the deployment configuration the stent is movable from an unloaded configuration to a loaded configuration
Implementation Method 2
impose a three-dimensional curvature that promotes a swirling blood flow, enhancing fracture resistance and inhibiting vascular diseases
Data Source
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AI summary
A stent (10) suitable for deployment in a blood vessel to support at least part of an internal wall of the blood vessel comprises a plurality of longitudinally spaced-apart annular elements (11), and a plurality of connecting elements (12) to connect adjacent annular elements (11). Each connecting element (12) is circumf erentially offset from the previous connecting element (12). Upon application of a load to the stent (10), the stent (10) moves from an unloaded configuration to a loaded configuration. In the loaded configuration the longitudinal axis of the stent (10) is curved in three-dimensional space, and the stent (10) is helically shaped.