Clot Retrieval System With Expandable Nitinol Basket
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Solution Overview
Problem
Current medical devices for removing blood clots from intracranial vessels are ineffective in addressing hard, organized thrombi, often causing embolization and vessel injury due to their design limitations, such as requiring proximal occlusion and failing to dislodge clots from vessel walls.
Innovation Solution
A deployable system using a pull wire with a distal body comprising memory metal strips that expand to capture clots, allowing for retrieval without proximal occlusion and minimizing embolization risks, manufactured from a single nitinol tube using laser cutting to form a basket shape, enabling navigation through small catheters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If currently available thrombus removal devices (MERCI, PENUMBRA, SOLITAIRE, TREVO) are used, then the device can be delivered through tortuous vessels, but the device fails to effectively remove hard organized thrombus and causes embolization
Solution Approach 1:
The device is divided into multiple components: a delivery catheter, an expandable basket with radially arranged wires, and a retrieval mechanism. The basket segments into individual wires that can independently engage the thrombus, allowing effective capture without requiring proximal occlusion, thereby reducing embolization risk while maintaining removal effectiveness
Solution Approach 2:
The basket transitions from a compressed delivery state to an expanded retrieval state through radial expansion of the wires. This dynamic transformation allows the device to navigate tortuous vessels in a compact form and then expand at the target site to effectively engage and secure hard organized thrombus for removal without causing embolization
2Ease of operation
If the device is made small and flexible to navigate through tortuous vessels, then the device can be delivered through microcatheters, but the device lacks strength to dislodge strongly adherent thrombus
Solution Approach 1:
The basket is nested within the delivery catheter in a compressed state, allowing it to pass through tortuous vessels and microcatheters with ease. Once deployed, the basket expands radially outward from the catheter, transforming from a flexible delivery configuration to a rigid retrieval configuration capable of dislodging strongly adherent thrombus while maintaining navigability
3Reliability
If the device requires proximal occlusion to remove thrombus, then the thrombus can be secured during removal, but the risk of further ischemia and vessel injury increases
Solution Approach 1:
The device extracts the requirement for proximal occlusion by using a distal basket expansion mechanism that secures the thrombus from the distal end of the vessel. The wires radially expand to engage the thrombus directly at the site of occlusion, allowing securement and removal without blocking proximal blood flow, thereby eliminating the risk of additional ischemia and vessel injury associated with proximal occlusion techniques
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 removes blood clots from intracranial vessels without causing further ischemia or vessel injury, allowing for multi-use and safe operation within the same patient treatment.
Implementation Method 1
a plurality of proximal memory metal strips located at the proximal end... The distal body has a relaxed state wherein the distal body has a first height and width and a collapsed state wherein the distal body has a second height and width
Implementation Method 2
manufactured from a single nitinol tube using laser cutting to form a basket shape
Data Source
AI summary
Catheter-delivered endovascular medical devices are described. The devices may include a pull wire attached to a distal body. The distal body may be formed of a distal body outer body comprising a basket comprised of a plurality of cells defined by a plurality of basket strips and a distal body inner body located in the interior of the distal body outer body and comprising a plurality of distal braided mesh openings formed by a plurality of woven linear strands. The distal braided mesh openings may be smaller than the cells when the device is in the relaxed state. Methods of using and making the devices are also described.