Thrombus Retrieval Device With Twistable Loop Trap
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Solution Overview
Problem
Existing thrombectomy devices often break up thrombi during removal and struggle to capture obstructions in narrow vessels due to their size and design limitations.
Innovation Solution
A flexible object capture device with a conical trap element and a catheter system that can twist into a loop, allowing for a small footprint and complete vessel closure, using a porous material like fine nylon mesh to capture debris without breaking it, and featuring a trigger wire mechanism to adjust the loop size for various vessel diameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple open ended catheter is used for thrombus aspiration, then the device structure is simple, but the catheter is too large to be passed through narrow vessels and tortuous vasculature
Solution Approach 1:
The trap element is collapsed inside the catheter during delivery, similar to a nested doll structure. The trap element can be compressed to a small profile that fits within the catheter lumen, then expands at the target site to form the capture chamber. This allows the device to pass through narrow vessels while still providing a large capture volume when deployed.
Solution Approach 2:
The trap element transitions from a compressed static state during delivery to an expanded dynamic state at the target site. The trap element can be deployed by expanding it radially outward from the catheter, transforming it from a compact delivery profile to a large capture configuration that can accommodate thrombi while maintaining access through narrow vessels.
2Quantity of substance
If a large catheter is used to capture the entire thrombus, then the capture capacity is sufficient, but the device cannot be passed through narrow vessels
Solution Approach 1:
The trap element is nested within the catheter during delivery, allowing the device to access narrow vessels with a small delivery profile. Once positioned at the thrombus site, the trap element expands to provide a large capture chamber capable of accommodating the entire thrombus, thus resolving the contradiction between access size and capture capacity.
Solution Approach 2:
The device transitions from a one-dimensional linear delivery profile to a three-dimensional expanded capture structure. The trap element expands radially outward from the catheter, creating a volumetric capture chamber that can hold large thrombi while the delivery system remains compact for navigating narrow vessels.
3Ease of operation
If aspiration is used to remove thrombus, then the removal process is simple, but the thrombus breaks up during the procedure
Solution Approach 1:
The trap element is divided into multiple segments or struts that can be collapsed together for delivery and then separated or expanded at the target site. This segmentation allows the trap to be delivered through narrow vessels in a compressed state and then expand to form a large capture chamber that can contain the entire thrombus without breaking it up during removal.
Solution Approach 2:
The trap element is made from flexible materials such as shape memory alloys or elastic polymers that can be compressed for delivery and then expand to form a stable capture chamber. The flexible structure maintains thrombus integrity by providing a gentle, conforming capture surface that holds the thrombus together during removal, unlike rigid aspiration catheters that can fragment the thrombus.
4Quantity of substance
If the trap element is made large to capture all debris, then the capture completeness is improved, but the device footprint increases and cannot navigate tortuous vasculature
Solution Approach 1:
The trap element is nested within the catheter or delivery system during delivery, minimizing the device footprint to navigate tortuous vasculature. Once positioned at the target site, the trap element expands to form a large capture chamber that can accommodate all debris and thrombus material, thus achieving both small delivery profile and large capture capacity.
Solution Approach 2:
The device footprint dynamically changes from a small compressed state during delivery to a large expanded state at the target site. The trap element transitions from a compact configuration that can navigate tortuous vessels to an expanded configuration that provides complete debris capture, resolving the contradiction between deliverability and capture capacity.
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 captures and removes thrombi or debris in its entirety without breaking, suitable for narrow vessels, and can be used in tortuous vasculature with a small footprint, ensuring complete removal of thrombi and small fragments.
Implementation Method 1
The trap element may be made of a substantially impermeable material, possibly with one or more small openings therein, but it is preferably made from a porous material. The openings or pores are sufficiently small to trap obstructing material, such as a thrombus, but large enough to allow the passage of blood or other fluid.
Data Source
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AI summary
A thrombus retrieval device (10) includes a flexible catheter (12), a retrieval wire (26) fixed to the distal end (14) of the catheter (12) and which extends out of the catheter (12) at first and second apertures in the wall of the catheter (12). A trap element (28) typically made of a porous fabric material, is attached to the catheter (12) from the distal end (14) across the location of the apertures. The trigger wire (26) can be pulled in a proximal direction, which causes the catheter (12) to twist so as to form a loop. The trap element (28), attached to the catheter at location in which it loops, forms a net for trapping thrombi or other obstructions within a patient's lumen.