Stent Graft with Variable Wall Thickness for Anastomosis Strength
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Solution Overview
Problem
Stent grafts with small thicknesses used in treating arterial dissections are prone to ripping and blood leakage during anastomosis, complicating the treatment process and potentially leading to treatment insufficiency.
Innovation Solution
A stent graft design with a graft thickness greater than the diameter of its wire members, featuring enhanced liquid retainability on the outer surface and reduced liquid retainability on the inner surface, to improve anastomosis and reduce the risk of blood leakage, while embedding wire members partially within the graft to prevent protrusion and enhance force dispersion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the graft thickness is reduced to fit the stent graft on a fine catheter, then the deliverability and ease of insertion are improved, but the strength and reliability of the graft deteriorate, causing ripping and blood leakage
Solution Approach 1:
The graft is designed with non-uniform thickness: thinner at the distal end (1-3mm) for easier delivery through catheters, and thicker at the proximal end (3-6mm) for enhanced strength during anastomosis. This local variation in thickness allows the graft to simultaneously satisfy both deliverability and strength requirements in different spatial locations.
2Shape
If the graft thickness is reduced, then the outer diameter is decreased for better catheter compatibility, but the resistance to ripping and blood leakage during anastomosis decreases
Solution Approach 1:
The graft exhibits spatially varying thickness to balance dimensional constraints and mechanical strength. The distal portion maintains small outer diameter (1-3mm) for catheter compatibility, while the proximal portion increases outer diameter and thickness (3-6mm) to provide sufficient strength for surgical anastomosis and resist ripping and blood leakage.
3Reliability
If the graft thickness is increased to improve strength, then the resistance to ripping is improved, but the ability to be inserted through fine catheters is reduced
Solution Approach 1:
The graft is segmented into distinct thickness zones: a distal segment with thinner walls (1-3mm) optimized for delivery through fine catheters, and a proximal segment with thicker walls (3-6mm) optimized for strength during implantation and anastomosis. This segmentation allows each portion to be optimized for its specific functional requirement.
4Strength
If the graft thickness is increased, then the strength during anastomosis is improved, but the outer diameter increases making catheter insertion difficult
Solution Approach 1:
The graft employs local quality variation with thickness transitioning from 1-3mm at the distal end to 3-6mm at the proximal end. This allows the proximal region to have larger outer diameter and greater strength for anastomosis, while the distal region maintains small outer diameter for catheter insertion, resolving the contradiction between strength and insertability.
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 design enhances the strength and durability of the stent graft, reducing the risk of ripping and blood leakage, facilitating effective anastomosis and improving treatment convenience by maintaining blood flow and preventing blood clot formation.
Implementation Method 1
the graft has liquid retainability that is greater on outer circumferential surface side of the graft than on inner circumferential surface side of the graft
Data Source
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AI summary
Provided is a stent graft that is able to improve convenience in treatment. A stent graft 1 includes a tubular graft 12 and at least one stent 11. The at least one stent 11 is disposed in a region corresponding to part or all of the graft 12, and includes one or a plurality of wire members 11w. The graft 12 has a thickness d12 that is greater than a diameter d11 of at least one of the one or the plurality of wire members 11w of the at least one stent 11.