Axially Compressible Bare Stent for Aortic Dissection
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Solution Overview
Problem
Existing stents for treating aortic dissection and aneurysm, particularly type A lesions, face challenges such as large diameter requirements, difficulty in delivery through femoral arteries, insufficient radial support force, and potential obstruction of branch arteries, especially in Asian patients with thinner vessels.
Innovation Solution
A bare stent with at least two layers of woven meshes, comprising first and second wires of different diameters, allowing axial compression and radial expansion, with sparse mesh areas at branch arteries to minimize obstruction and enhance radial support force, facilitating delivery through conventional catheters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a dense mesh stent is used to treat type A aortic dissection, then radial support force is improved, but delivery through femoral artery becomes difficult due to large diameter requirement
Solution Approach 1:
The stent is designed with a nested structure where the stent body is positioned inside a delivery catheter during delivery, and the mesh structure allows the stent to be compressed into a smaller delivery configuration while maintaining its expanded radial support function at the treatment site
Solution Approach 2:
The stent transitions from a compressed dynamic state during delivery through the femoral artery to an expanded static state at the treatment site, allowing the same structure to satisfy both small delivery diameter and large expanded diameter requirements
2Strength
If a covered stent is used for EVAR intervention, then radial support and false lumen obstruction are improved, but branch artery obstruction risk increases
Solution Approach 1:
The stent features variable mesh density with denser mesh regions providing radial support and sparser mesh regions at branch artery locations to minimize obstruction, allowing different functional zones within the same stent structure
Solution Approach 2:
The bare mesh structure allows blood flow through the stent body while still providing radial support, unlike covered stents that completely block flow, reducing the risk of branch artery obstruction while maintaining therapeutic effect
3Reliability
If open surgery is performed for aortic dissection, then treatment efficacy is improved, but intraoperative mortality and re-operation rate increase
Solution Approach 1:
The mechanical open surgical procedure is replaced with an endovascular intervention using a self-expanding or balloon-expandable stent delivered through catheters, transitioning from open mechanical reconstruction to minimally invasive endovascular mechanics
Data Source
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AI summary
A stent (10, 20) for aorta is formed by weaving at least two types of filaments having different diameters, such as a first filament (13, 23) and a second filament (14, 24). The stent is configured to be at least partially compressible and extensible along the axial direction of the stent in a natural release state, wherein the first filament (13, 23) has a diameter of 20-150 µm, and the second filament (14, 24) has a diameter of 150-800 µm. When the stent is used in the treatment of aortic aneurysm and/or aortic dissection lesions, due to the axial compressibility and extensibility of the stent, low liquid permeability and strong radial support force are provided where needed in the aorta, and due to the axial stretchability thereof, the stent can be easily assembled to a delivery system having an appropriate diameter. Also provided are a stent kit comprising the stent and a stent delivery system.