Braided Flow-Diverter Structure for Tortuous Vessel Apposition
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Solution Overview
Problem
Current flow-diverting stents or braids face challenges in approximating the vessel wall across the neck of an aneurysm, especially in tortuous vessels, leading to crimping, kinking, inadequate porosity, and undesired blockage of blood flow to branching vessels.
Innovation Solution
Expandable devices with small diameter strands, improved flexibility, and a novel heat setting process to reduce oxide layer thickness, enabling consistent apposition and reduced friction for effective deployment in tortuous vessels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current flow-diverting stent designs are used in tortuous vessels, then the device can be deployed, but it suffers from crimping and kinking that compromise its functionality
Solution Approach 1:
The patent changes the geometric parameters of the stent by reducing strand diameter from conventional sizes to 0.001 inches (25.4 μm) or less, and adjusting braid angle to 45-60 degrees. These parameter changes enable the stent to navigate tortuous vessels without crimping or kinking while maintaining shape stability and functionality.
Solution Approach 2:
The patent employs composite material structures with cobalt-chromium outer layers and nickel-titanium inner cores, combining materials with complementary properties. The cobalt-chromium provides surface durability and oxidation resistance, while the nickel-titanium provides elasticity and shape memory, resolving the contradiction between maintaining shape stability and adapting to tortuous vessel geometries.
2Reliability
If the stent is expanded to block blood flow into the aneurysm, then flow diversion is achieved, but porosity becomes inadequate for proper function
Solution Approach 1:
The patent controls porosity by precisely adjusting braid angle (45-60 degrees) and strand diameter (0.001 inches or less), creating an optimized balance between flow diversion capability and adequate porosity. The tight braid pattern with fine strands maintains sufficient open space for blood flow while achieving effective flow diversion into the aneurysm.
3Reliability
If the stent is positioned across the aneurysm neck, then flow diversion is achieved, but blood flow to branching vessels is undesirably blocked
Solution Approach 1:
The patent applies local quality by positioning the stent to selectively cover the aneurysm neck while preserving flow to branching vessels. The precise geometric control with strand diameters of 0.001 inches or less allows the stent to be tuned for specific vessel configurations, treating the aneurysm while maintaining adequate blood flow to collateral vessels.
4Stability of the object's composition
If conventional heat setting processes are used, then the stent achieves basic shape retention, but oxide layer thickness increases reducing performance
Solution Approach 1:
The patent employs inert atmosphere heat treatment processes that minimize oxide layer formation on the stent strands. By treating the stent in controlled atmospheric conditions with reduced oxygen availability, the process achieves necessary shape retention while suppressing harmful oxide layer formation that would otherwise increase friction and degrade performance.
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 devices achieve improved flexibility, shape retention, and reduced friction, allowing for precise positioning and effective blood flow diversion to promote aneurysm thrombosis and healing, even in challenging vascular geometries.
Implementation Method 1
Some aspects of the present technology include expandable devices that have been heat set according to, for example, a novel heat setting process disclosed herein. The resulting expandable devices have a reduced oxide layer thickness and improved shape retention over a range of strand sizes.
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3~4
AI summary
Vascular expandable devices and associated methods are disclosed herein. An expandable vascular device can include a generally tubular sidewall formed of a plurality of braided strands. The device can have a compressed state for delivery in which the device has a compressed state diameter of 0.027 inches or less. The device can have an expanded state in which the device has an expanded state diameter. A full expansion distance of the device corresponds to a longitudinal unconstrained distance at which the distal end of the expandable device attains the expanded state diameter. The full expansion distance can be 20 mm or less.