Nested Clot Retrieval Device with Flexible Braid
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Solution Overview
Problem
Current medical procedures for removing clot material from blood vessels face challenges such as dislodging fragments that can cause further obstruction, trauma to vessel walls, and incomplete clot removal due to the size and design of existing retrieval devices, particularly in tortuous anatomy and bifurcations.
Innovation Solution
A clot retrieving device with an elongated shaft and a retrieval assembly featuring a flexible cover and capture structure that expands within the vessel to engage the clot, allowing for secure ensheathment and removal of clot material without causing significant trauma, utilizing a braid or mesh structure with a superelastic material for flexibility and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stent is used to push the clot to the side of the vessel, then blood flow is re-established, but the stent may not sufficiently retain the clot and fragments may dislodge causing further obstruction
Solution Approach 1:
The device employs a nested structure where an inner capture structure (stent or basket) is placed within an outer capture structure (retrieval device). The inner structure engages the clot first, then the outer structure envelops both the inner structure and clot, creating a nested configuration that secures the clot during retrieval through multiple concentric containment layers
Solution Approach 2:
The outer capture structure utilizes a flexible braid or mesh that can conform to the vessel geometry and clot shape. This flexible shell envelops the clot and inner structure, adapting to tortuous anatomy and bifurcations while maintaining secure retention, preventing fragment dislodgement through flexible containment rather than rigid constraint
2Productivity
If an expanded stent is dragged through the vasculature to remove the clot, then the clot can be retrieved, but significant trauma is caused to the vessel walls
Solution Approach 1:
The outer capture structure is designed as a flexible braid or mesh that can compress to a low profile for navigation and then expand to envelop the clot. This flexible shell conforms to the vessel lumen without rigid contact, minimizing trauma to vessel walls during both navigation and retrieval phases while maintaining clot containment
Solution Approach 2:
The device transitions dynamically between compressed and expanded states. The braid or mesh structure can be compressed to navigate tortuous anatomy and bifurcations, then expanded to envelop and secure the clot. This dynamic transformation allows efficient clot removal while adapting to varying vessel geometries without causing trauma
3Reliability
If the retrieval device is made large enough to securely retain the clot, then clot retention is improved, but the device becomes too large and immobile to navigate tortuous anatomy
Solution Approach 1:
The device employs dynamic state transformation, transitioning from a compressed low-profile state for navigation through tortuous anatomy and bifurcations to an expanded state for clot engagement and retention. The braid or mesh structure enables this transformation, allowing the device to be small during delivery but large during retrieval
Solution Approach 2:
The nested configuration allows the inner capture structure to be contained within the outer capture structure during navigation, presenting a compact profile. Upon deployment, the outer structure expands to envelop the inner structure and clot, providing secure retention. This nesting enables the device to be both navigable and effective
4Reliability
If the stent is oversized compared to the vessel, then clot retention is improved, but the stent pulls the arteries and strips the cellular lining causing hemorrhagic stroke
Solution Approach 1:
The outer capture structure uses a flexible braid or mesh that can envelop the clot and inner structure while conforming to the vessel lumen. This flexible shell provides adequate clot retention through envelopment rather than oversized rigid constraint, minimizing contact stress on the vessel wall and preventing stripping of the cellular lining
Solution Approach 2:
The device changes its physical parameters (size, shape, stiffness) through transformation from compressed to expanded state. In the expanded state, the braid or mesh provides sufficient clot retention while maintaining flexibility to conform to the vessel, avoiding the fixed oversized dimension that would cause vessel damage
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 device effectively retrieves clot material with reduced risk of dislodging fragments and trauma to vessel walls, facilitating complete removal and minimizing procedural complications in complex vascular anatomy.
Implementation Method 1
utilizing a braid or mesh structure with a superelastic material for flexibility and stability
Data Source
AI summary
Devices for removing clot material from a blood vessel lumen and associated systems and methods are disclosed herein. A clot retrieving device may include, for example, an elongated member, a cover having proximal, intermediate, and distal portions. The cover may be slideably coupled to the distal region of the elongated member at a connector. The cover may have an inner layer and an outer layer. The inner layer may have (a) a first cross-sectional dimension at the proximal portion of the cover, (b) a distally increasing cross-sectional dimension along the intermediate portion of the cover, and (c) a second cross-sectional dimension at the distal portion of the cover, wherein the second cross-sectional dimension is greater than the first cross-sectional dimension. The outer layer may have a cross-sectional dimension that is generally constant along the distal portion and the intermediate portion of the cover.