Nitinal Clot Retrieval Basket with Memory Metal Strips
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Solution Overview
Problem
Current intravascular thrombus removal devices are ineffective in removing hard, organized blood clots from the brain and often cause embolization due to their design, requiring proximal vessel occlusion and being difficult to maneuver through tortuous intracranial vasculature.
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, manufactured from a single nitinol tube using laser cutting to form a basket-like structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If current intravascular thrombus removal devices are used, then device simplicity is maintained, but effectiveness in removing hard organized clots deteriorates
Solution Approach 1:
The device is divided into multiple functional segments including a distal basket portion with memory metal strips for clot capture, a proximal tube for structural support, and a middle portion with laser-cut patterns for flexibility and engagement. This segmentation allows each part to be optimized for its specific function while maintaining overall device simplicity.
Solution Approach 2:
The device utilizes composite construction combining memory metal strips (for active clot engagement and expansion), laser-cut patterned sections (for flexibility and radial strength), and biocompatible catheter materials. This composite approach enables the device to effectively remove hard organized clots while maintaining manufacturability.
2Ease of manufacture
If device structure is simplified, then ease of manufacture is improved, but ability to navigate tortuous intracranial vasculature deteriorates
Solution Approach 1:
The device incorporates laser-cut patterned sections with curved geometries that provide flexibility and ability to conform to tortuous vessel paths. The memory metal strips are configured with specific curvatures that enable navigation through complex intracranial anatomy while maintaining structural integrity.
Solution Approach 2:
The device utilizes thin, flexible memory metal strips and laser-cut patterned sections that can bend and flex to navigate tortuous vasculature. These flexible components maintain their structural integrity while adapting to complex vessel geometries, eliminating the need for complex articulated mechanisms.
3Reliability
If proximal vessel occlusion is required, then clot capture security is improved, but risk of further ischemia and vessel injury deteriorates
Solution Approach 1:
The device extracts and removes the clot from the vessel through the distal basket portion alone, without requiring proximal occlusion. The basket is designed to securely capture and encapsulate the clot within its structure, allowing retrieval through the catheter without needing to block the proximal vessel, thereby eliminating the associated risks of ischemia and vessel injury.
Solution Approach 2:
The distal basket acts as an intermediary structure that captures and holds the clot securely during retrieval. The memory metal strips and laser-cut patterns create a secure enclosure that prevents clot embolization without requiring proximal vessel occlusion, serving as a mediator between the clot and the retrieval system.
4Volume of moving object
If device size is reduced for intracranial delivery, then ability to navigate small vessels is improved, but strength to dislodge strongly adherent thrombus deteriorates
Solution Approach 1:
The device transitions from a compressed delivery configuration to an expanded working configuration. The memory metal strips are designed to expand radially upon deployment, transforming the device from a small profile suitable for intracranial delivery into a larger structure capable of engaging and dislodging strongly adherent thrombus with sufficient force.
Solution Approach 2:
The device utilizes radial expansion to resolve the size-strength contradiction. In the delivery dimension (axial compression), the device maintains a small profile for navigating intracranial vessels. Upon deployment, it expands in the radial dimension to create sufficient engagement surface area and mechanical strength for dislodging adherent thrombus without requiring increased axial length or outer diameter.
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
Enables safe and effective removal of hard clots from intracranial vessels without embolization, navigating tortuous paths and being retrievable without proximal vessel occlusion, improving clinical efficacy in acute ischemic stroke management.
Implementation Method 1
a plurality of memory metal strips (414) configured to expand from a compressed state to a relaxed state
Implementation Method 2
manufactured from a single nitinol tube using laser cutting
Data Source
AI summary
Catheter-delivered endovascular medical devices are described. The devices may include a pull wire attached to a distal body, which may be formed of a basket or other framework that has a plurality of cells. The pull wire may be extra long to allow a secondary device, such as an aspiration catheter, balloon or stent, to be delivered over the pull wire while the pull wire is in an intracranial artery. Methods of using and making the devices are also described.