Self-Adjusting Stent Assembly for Vessel Diameter Adaptation
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Solution Overview
Problem
Current self-expanding stents are designed for specific vessel diameters, leading to sizing errors when used in vessels with varying diameters, which can result in undersizing or oversizing, causing complications such as thrombosis, re-stenosis, or vessel perforation.
Innovation Solution
A self-expanding stent assembly that can expand to a range of diameters from 5.5 mm to 9 mm, with a chronic radial force of 0.20 N/mm to 0.33 N/mm, featuring a knitted stent jacket with an expansible mesh structure that adapts to varying vessel diameters, reducing the need for multiple stent sizes and minimizing vessel trauma.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a self-expanding stent is designed to fit a specific vessel diameter, then the stent can provide adequate support and minimize vessel wall damage, but the stent cannot accommodate variances in vessel diameters of 5 mm or larger
Solution Approach 1:
The stent assembly incorporates a dynamic expansion mechanism that allows it to transition from a compressed delivery state to multiple expanded diameter states. The stent can be deployed to match the actual vessel diameter through controlled expansion, rather than being fixed at a single diameter. This dynamic capability enables the same stent to adapt to vessels with diameters varying by 5 mm or more while maintaining precise dimensional control at the target diameter.
Solution Approach 2:
The stent assembly utilizes parameter changes by allowing the expansion diameter to be adjusted based on the measured vessel diameter. The system enables changing the critical diameter parameter from a fixed value to a variable that can be selected within a range, thereby accommodating vessel diameter variations while maintaining manufacturing precision for each specific diameter target.
2Measurement precision
If imaging techniques are used to determine the required stent size, then the stent can be sized more accurately, but the procedure becomes more complex and time-consuming
Solution Approach 1:
The stent assembly is designed as a universal platform that can be used across a wide range of vessel diameters without requiring different stent designs. This multi-functionality reduces the complexity of selecting and deploying the correct stent size, as the same stent platform can be expanded to match various vessel diameters determined through imaging techniques.
3Adaptability or versatility
If a stent is oversized to accommodate larger vessel diameter variations, then the stent can fit more vessels, but the stent may stress the vessel walls and generate re-stenosis or perforation
Solution Approach 1:
The dynamic expansion capability allows the stent to be deployed at the precise vessel diameter rather than using a fixed oversized design. This ensures the stent provides adequate support without excessive radial force that could stress the vessel wall and cause re-stenosis or perforation.
Solution Approach 2:
The stent assembly enables local optimization of the expansion diameter to match the specific vessel segment being treated. By adjusting the expansion parameter to the actual local vessel diameter, the stent provides adequate radial support where needed without applying excessive stress to the vessel wall.
4Object-affected harmful factors
If a stent is undersized to minimize vessel wall stress, then the stent can reduce the risk of re-stenosis and perforation, but the stent may shift or fail to achieve full apposition, increasing thrombosis risk
Solution Approach 1:
The dynamic expansion mechanism allows the stent to achieve full expansion and apposition against the vessel wall at the correct diameter, ensuring stable positioning and thrombosis prevention without excessive oversizing that would cause vessel wall stress.
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 assembly effectively adapts to a wide range of vessel diameters, reducing sizing errors and complications, providing stable endothelial cell growth and minimizing the risk of thrombosis and re-stenosis while allowing for better pharmacological delivery and embolic protection.
Implementation Method 1
Self-expanding stents generally have a tubular shape cut in a pattern that results in spring-like movement of the stent assembly in the radial direction
Implementation Method 2
The stent assembly is configured to expand from an initial diameter to one or more expanded diameters within a range of expanded diameters while applying a radial force
Data Source
AI summary
A method of using a self-adjusting stent assembly includes estimating body lumen diameter(s) associated with a portion of a body lumen in which a stent assembly will be placed; determining, based on the estimated diameter(s), target expanded stent diameter(s) of the stent assembly which is to be placed in the portion of the body lumen; selecting the stent assembly for stenting the portion of the body lumen, wherein the stent assembly is configured to: expand from an initial to expanded diameters within a range of expanded diameters; wherein the range of expanded diameters is from about 9 mm to about 5.5 mm; and wherein the target expanded stent diameter(s) is/are within the range of expanded diameters; and apply a chronic radial force to a wall that forms the portion of the lumen, wherein the radial force is less than about 0.33 N/mm.