Dual-Layer Clot Retriever for Atraumatic Soft Clot Capture
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Solution Overview
Problem
Existing clot retrieval devices face challenges in effectively capturing and removing clots of varying compositions, such as fibrin-rich and soft clots, due to issues with radial force, vessel trauma, and difficulty navigating tortuous vessels, leading to incomplete removal and potential vessel damage.
Innovation Solution
A dual-layer clot retrieval device with an inner and outer expandable body, utilizing a flexible design and self-expanding materials like Nitinol, allows for secure grip and navigation through complex vasculature, minimizing vessel damage and ensuring complete clot capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If stent-like clot retriever uses high radial force to grip all clot types, then grip strength is improved, but vessel trauma increases
Solution Approach 1:
The device divides the clot engagement function into two separate components: the inner body with hooks for penetrating and anchoring into the clot, and the outer body with gentle loops for atraumatic vessel contact. This segmentation allows each component to specialize - the inner body provides strong grip without requiring high radial force that would trauma the vessel, while the outer body provides structural support and protection.
Solution Approach 2:
Instead of using outward radial expansion to grip the clot (conventional approach), this device uses inward-directed hooks on the inner body that penetrate and anchor into the clot from the inside. The outer body loops are inverted to face inward, creating a protective cage rather than a compressive force, thereby achieving clot retention without vessel trauma.
2Object-affected harmful factors
If stent-like clot retriever uses low radial force to remain atraumatic, then vessel trauma is reduced, but grip strength on clot decreases
Solution Approach 1:
The device separates the functions of clot engagement and vessel protection into distinct components. The inner body with hooks handles clot engagement through mechanical penetration and anchoring, while the outer body with gentle loops handles vessel protection through atraumatic contact, eliminating the need for high radial force.
Solution Approach 2:
The inner body acts as an intermediary between the outer body and the clot. It transmits the gripping force directly to the clot through hooks and anchors, bypassing the need for the outer body to apply high radial force that would trauma the vessel. The intermediary inner body protects the vessel while enabling strong clot grip.
3Reliability
If stent-like clot retriever pins clot between device and vessel wall, then clot retention is improved, but shear forces increase causing fragmentation
Solution Approach 1:
Instead of pinning the clot between the device and vessel wall (conventional approach), this device inverts the mechanism by having the inner body hooks penetrate and anchor into the clot from within, while the outer body loops face inward to protect the clot. This eliminates lateral shear forces against the clot surface that cause fragmentation.
Solution Approach 2:
The device applies partial action by using only the necessary minimal force through hooked engagement and anchoring to secure the clot, rather than excessive radial compression. This selective application of force achieves reliable retention without generating harmful shear forces that would fragment the clot.
4Adaptability or versatility
If clot retrieval device navigates tortuous vessels with extreme bends, then access capability is improved, but device flexibility requirements increase
Solution Approach 1:
The device employs a flexible construction with the inner body and outer body capable of bending and conforming to tortuous vessel geometries. The struts and connecting elements are designed to flex while maintaining structural integrity, allowing the device to navigate extreme bends in the aortic arch and carotid arteries without compromising access capability or device integrity.
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 achieves efficient first-pass clot removal by securely pinching and inverting the clot, reducing vessel trauma and preventing clot fragmentation, suitable for diverse clot types and anatomical challenges.
Implementation Method 1
a self-expanding stent-like body
Data Source
Figure 1~2
Figure 3A~3C
Figure 4A~5A
AI summary
Designs are disclosed for devices capable of removing both firm and soft clots from body vessels that can have dual layers where an inner expandable body of cells runs within an outer expandable cage of cells. The designs can feature a constrained delivery configuration and an expanded deployed configuration. An outer cage can have wide opening struts to allow for clot integration into the device. Both the inner body and outer cage can be configured with shapes to pinch a clot in addition to embedding in it. The devices can also be capable of having a portion of the outer cage fold and invert proximally after engaging with a target clot to internalize it. These factors can increase the device's ability to capture clots of all compositions, allowing for safer and more efficient flow restoration.