Clot Retrieval System with Memory Metal Strips
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Solution Overview
Problem
Current devices for removing blood clots from intracranial vessels are ineffective in addressing hard, organized thrombi, often causing embolization and requiring proximal vessel occlusion, which can lead to further ischemia and vessel injury.
Innovation Solution
A deployable system comprising a pull wire with a distal body featuring memory metal strips that expand to capture and encase clots, allowing for retrieval without proximal occlusion and minimizing risk of embolization, featuring a claw mechanism for secure clot removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If currently available thrombus removal devices (MERCI, PENUMBRA, SOLITAIRE, TREVO) are used, then some level of clot removal is achieved, but they are ineffective at removing hard, organized thrombus and often cause embolization or require proximal occlusion
Solution Approach 1:
The device divides the clot engagement function into multiple segments: the distal body with claw mechanism for capture, the basket for containment, and the proximal strips for engagement. This segmentation allows each component to perform its specific function effectively, enabling reliable removal of hard thrombus without causing embolization.
Solution Approach 2:
The device performs preliminary engagement of the thrombus using the proximal memory metal strips and claw mechanism before full retrieval. This preliminary action secures the clot in place, preventing embolization during the removal process, and allows the operator to assess engagement before proceeding with full extraction.
2Strength
If self-expanding stents (SOLITAIRE, TREVO) are used to entangle thrombus, then the vessel is temporarily opened, but the clot is compressed against the vessel wall and breaks up into pieces that embolize upon retrieval
Solution Approach 1:
The device extracts the clot from the vessel by engaging it with the proximal strips and claw mechanism, then pulling it into the distal body for secure containment. This extraction approach removes the clot entirely from the vessel rather than compressing it against the wall, preventing fragmentation and embolization while maintaining vessel patency.
Solution Approach 2:
The device uses dynamic components including the expandable distal body, the movable proximal strips, and the rotating claw mechanism. These dynamic elements allow the device to adapt to the clot shape, secure engagement, and retrieve the clot intact without fragmentation, resolving the contradiction between vessel opening and clot integrity.
3Length of moving object
If a device is made small and flexible to navigate tortuous vessels, then it can navigate through microcatheters, but it becomes difficult to dislodge strongly adherent thrombus from the vessel wall
Solution Approach 1:
The device employs a nested structure where the proximal strips and claw mechanism are contained within the distal body during delivery. This nesting allows the device to pass through microcatheters in a compact form while maintaining the capability to deploy sufficient force through the proximal engagement elements to dislodge strongly adherent thrombus.
Solution Approach 2:
The device concentrates the force application capability at the proximal end where the memory metal strips and claw mechanism are located, while keeping the distal body flexible for navigation. This local quality allows the device to navigate tortuous vessels with flexibility while simultaneously providing sufficient force at the clot engagement point to dislodge adherent thrombus.
4Reliability
If a device requires proximal occlusion of the vessel for retrieval, then clot removal can be achieved, but further ischemia and vessel injury occur
Solution Approach 1:
The device performs self-engagement of the clot through the proximal memory metal strips that automatically expand and contact the thrombus upon deployment. This self-service mechanism secures the clot without requiring proximal occlusion, allowing retrieval while maintaining blood flow and preventing ischemia and vessel injury.
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 removes blood clots from intracranial vessels by securely capturing and retrieving them without causing further ischemia or vessel injury, addressing the limitations of existing devices.
Implementation Method 1
a plurality of proximal memory metal strips located at the proximal end, each having a proximal end and a distal end
Data Source
Figure 1A~1B
Figure 2A~2C
Figure 3A~3H
AI summary
A platform of devices for removing obstructions and other objects within a blood vessel or other interior lumen of an animal is provided. The system may be deployed in the lumen from a catheter(s) and may include a strain gauge for measuring tension on the pull wire. A number of different baskets designs are disclosed. Methods of manufacturing such baskets out of a single tube of a memory metal without the need for any welding, and methods of use are also disclosed.