Nested Clot Retrieval Device for Vessel Wall Protection
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Solution Overview
Problem
Current methods for removing clot material from blood vessels, such as stents and tPA, face challenges like clot fragmentation, dislodgment, and vascular trauma, which can lead to further complications during ischemic stroke treatment.
Innovation Solution
A clot retrieving device with an elongated shaft and a retrieval assembly featuring a flexible cover and capture structure that self-expands to engage clot material, providing friction against the vessel wall to secure and remove the clot without dislodging it, reducing vascular trauma.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a stent is used to push the clot to the side of the vessel, then blood flow is re-established, but the clot may fragment or dislodge causing further blockages
Solution Approach 1:
The capture structure is nested within the stent, with the stent providing external support and the capture structure providing internal clot entrapment. This nested configuration allows the stent to push the clot while the capture structure prevents fragmentation and dislodgment, resolving the contradiction between rapid blood flow restoration and clot stability.
Solution Approach 2:
The capture structure acts as an intermediary between the stent and the clot, providing a mechanism that both pushes the clot (like the stent) and prevents fragmentation (unlike the stent alone). This intermediary structure enables the stent to effectively move the clot without causing the harmful fragmentation effect.
2Reliability
If tPA is administered to break down the clot, then clot dissolution occurs, but it takes time for tPA to reach and act on the clot
Solution Approach 1:
The device performs preliminary mechanical action by pushing the clot with the stent and capturing it with the capture structure, which can immediately restore blood flow. The tPA then acts as a supplementary chemical agent that continues the clot breakdown process over time, eliminating the need to wait for tPA to be the primary mechanism.
Solution Approach 2:
The invention replaces the purely chemical tPA system with a mechanical system (stent and capture structure) that provides immediate clot removal capability, while tPA serves as a supplementary chemical mechanism. This substitution eliminates the time delay inherent in relying solely on chemical dissolution.
3Ease of operation
If the stent is dragged through the vasculature to remove the clot, then the procedure is easy to perform, but the stent may not sufficiently retain the clot causing it to remain in the vasculature
Solution Approach 1:
The capture structure is nested within the stent, creating a hierarchical configuration where the stent provides the outer framework for easy navigation and the capture structure provides the inner mechanism for secure clot retention. This nested design maintains procedural simplicity while dramatically improving clot retention reliability.
Solution Approach 2:
The device is segmented into two functional components: the stent for navigation and clot pushing, and the capture structure for clot retention. This segmentation allows each component to be optimized for its specific function while working together, maintaining ease of operation through the stent's simple navigation while adding reliable retention through the capture structure.
4Productivity
If an expanded stent is used to drag the clot, then the clot can be moved to the catheter, but the stent causes undesired trauma to the vessel walls
Solution Approach 1:
The capture structure functions as a flexible shell that can conform to the vessel geometry and the clot shape, allowing efficient clot movement without the rigid stent directly contacting and traumatizing the vessel walls. The flexible capture structure absorbs mechanical stresses that would otherwise be transmitted to the vessel wall.
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 while minimizing the risk of fragmentation and vascular trauma, facilitating safer and more efficient restoration of blood flow during ischemic stroke treatment.
Implementation Method 1
providing friction against the vessel wall to secure and remove the clot
Data Source
Figure 1A~1B
Figure 2A~2C
Figure 2D~2F
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 shaft, a capture structure, a cover, and a connector coupled to the elongated shaft proximal of the capture structure. The connector may include an inner band and an outer band, wherein (a) the inner band at least partially surrounds a portion of the distal zone of the elongated shaft, (b) the outer band at least partially surrounds the inner band, and (c) the first portion of the cover is secured between the inner band and the outer band.