Dual Stent Blood Clot Retrieval System
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Solution Overview
Problem
Existing stent systems face challenges in securely capturing and retrieving blood clots, especially in the brain region, due to clot size or hardness, and the risk of clots coming off during withdrawal through blood vessels with varying diameters.
Innovation Solution
A stent system comprising a wire with a first stent connected to its distal portion and a second stent proximal to the first, where the second stent is movable and expandable to securely hold the blood clot between both stents, allowing for reliable capture and retrieval, even through blood vessels with changing diameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single stent is used to capture a blood clot, then the device structure is simple, but the ability to securely capture and retain hard or large blood clots is insufficient
Solution Approach 1:
The single stent is divided into two separate stents (first stent and second stent) positioned at different locations on the wire. The first stent captures the blood clot, while the second stent provides additional securing capability. This segmentation allows each stent to perform a specific function, improving overall capture reliability without requiring one overly complex single-stent design.
Solution Approach 2:
The second stent is designed to be movable and can be positioned to work in conjunction with the first stent. When deployed, the second stent can engage with the blood clot from a different position, creating a nested or overlapping configuration that secures the clot more effectively. This nested arrangement allows the system to handle larger and harder clots that a single stent cannot secure alone.
2Reliability
If the stent is expanded to capture large blood clots, then the capture capacity increases, but the ability to pass through microcatheters and blood vessels with limited diameter is reduced
Solution Approach 1:
The second stent is designed with movable characteristics, allowing it to transition between compressed and expanded states dynamically. During delivery, both stents are compressed to small profiles to pass through microcatheters and narrow blood vessels. Upon deployment, the stents expand to provide adequate capture capacity for large blood clots. This dynamic capability resolves the contradiction between capture capacity and deliverability.
Solution Approach 2:
By dividing the capture function into two separate stents, each stent can be optimized with smaller individual expansion dimensions while collectively providing sufficient capture capacity for large clots. The segmented approach allows each component to maintain a smaller delivery profile compared to a single large stent, improving ability to navigate narrow vessels while maintaining overall capture effectiveness.
3Productivity
If the stent is withdrawn through blood vessels with varying diameters, then the retrieval process is completed, but the risk of blood clot dislodgement increases
Solution Approach 1:
The second stent is positioned to work in conjunction with the first stent during retrieval. As the stent system is withdrawn through blood vessels with varying diameters, the second stent provides additional support and securing action, creating a nested configuration that prevents blood clot dislodgement. This nested arrangement ensures the blood clot remains securely held even when passing through confluences and bends in the vasculature.
Solution Approach 2:
The movable second stent can adjust its position and expansion state in response to changing vessel parameters during retrieval. When encountering confluences or bends, the second stent can be positioned to provide enhanced securing action. This ability to change parameters (position, expansion state) in response to varying conditions maintains blood clot retention reliability throughout the retrieval process through vessels with varying diameters.
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 system effectively captures and retains blood clots, preventing them from dislodging during withdrawal, even through confluences and bends in blood vessels, and is suitable for use in patients with harder clots formed after 8 hours, minimizing vessel damage.
Implementation Method 1
The first stent may be configured to expand while at least a portion of the first stent is located distal to a blood clot
Implementation Method 2
a second stent disposed on a portion of the wire proximal to the first stent, the second stent being configured to be movable toward or away from the first stent
Data Source
AI summary
A stent system according to the present invention is for use in retrieving a blood clot from the brain region and includes a wire; a first stent connected to a distal portion of the wire; a first outer sheath that covers and is fixed to a portion of the wire proximal to the first stent; and a second stent disposed on a portion of the wire proximal to the first stent, in which the second stent is configured to be movable toward or away from the first stent.