Clot Retrieval System 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 heart due to their design limitations, such as requiring vessel occlusion, failing to dislodge clots from vessel walls, and causing embolization of clot fragments.
Innovation Solution
A deployable system featuring a pull wire with a distal body comprising memory metal strips that expand to capture and encase clots, allowing for retrieval without vessel occlusion, and a catheter to envelope the system in a collapsed state for navigation through tortuous vessels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If current thrombus removal devices are used, then device simplicity is maintained, but the devices fail to dislodge hard, organized thrombus from vessel walls
Solution Approach 1:
The device employs a dynamic structure where the distal body can transition between collapsed and expanded states. The memory metal strips are configured to move from a compressed configuration during delivery to an expanded configuration at the treatment site, enabling the device to adapt its shape and size dynamically to engage with and dislodge thrombus effectively
Solution Approach 2:
The distal body is segmented into multiple memory metal strips that can independently expand and conform to the vessel wall and thrombus. This segmentation allows the device to engage with irregularly shaped thrombus more effectively while maintaining structural flexibility
2Reliability
If proximal vessel occlusion is used to retrieve thrombus, then thrombus removal is achieved, but further ischemia and vessel injury risk increase
Solution Approach 1:
The device extracts the thrombus from the vessel by expanding the distal body to encase the thrombus directly at the site of occlusion, then retrieving the encased thrombus through the microcatheter without requiring proximal vessel occlusion. This eliminates the need for balloon occlusion and associated ischemic risks
Solution Approach 2:
The distal body acts as an intermediary structure that mediates between the microcatheter and the thrombus. It provides a interface for thrombus engagement and encasement, enabling thrombus removal through a mechanism that does not require proximal occlusion or direct catheter-thrombus interaction
3Ease of operation
If the device is made small and flexible to navigate tortuous vessels, then vessel navigation capability is improved, but the device lacks strength to dislodge adherent thrombus
Solution Approach 1:
The device transitions from a flexible, compressed state during navigation to a rigid, expanded state during thrombus engagement. The memory metal strips provide structural support when expanded, enabling the device to dislodge adherent thrombus while maintaining navigability through tortuous vessels in the collapsed state
Solution Approach 2:
The device is nested within the microcatheter during delivery, allowing it to pass through tortuous vessels in a compressed, flexible state. Upon deployment, the distal body expands outward from the catheter lumen, transforming into a structurally robust configuration capable of engaging and dislodging thrombus
4Device complexity
If open-ended device structure is used for thrombus entrapment, then device simplicity is maintained, but thrombus embolization into other vessels occurs
Solution Approach 1:
The distal body employs localized engagement structures with the thrombus through its memory metal strip configuration. The strips are positioned and configured to create radial force against the thrombus, providing localized entrapment that prevents embolization while maintaining overall device simplicity
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 blood clots from intracranial arteries by capturing and retrieving clots without causing further ischemia or vessel injury, preventing embolization, and allowing for multi-use within the same patient treatment.
Implementation Method 1
a distal body comprising an interior, an exterior, a proximal end, a distal end, a plurality of proximal memory metal strips located at the proximal end
Data Source
AI summary
The invention relates to systems for removing obstructions and other objects within a blood vessel or other interior lumen of an animal. The system may be deployed in the lumen from a catheter and includes a pull wire having a proximal end and a distal end, and a distal body having a proximal hub, a basket, and a distal hub. In some embodiments, the distal body includes a plurality of proximal strips that form a closeable claw that is used to capture the obstruction. In other embodiments, the basket includes an enlarged opening that allows the object to enter the basket. Optionally, the basket includes x-ray markers adjacent to the enlarged openings to allow the operator to locate the openings, as well as twisting strips that connect the basket to the proximal hub. The present invention also relates to methods of making and using such systems.