Expandable Braid Catheter Tip for Clot Retrieval
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Solution Overview
Problem
Existing clot retrieval catheters face challenges in effectively removing acute blockages from blood vessels due to small diameters, fixed tip sizes, and inadequate flexibility, leading to issues like clot fragmentation, lodging, and reduced aspiration efficiency.
Innovation Solution
A clot retrieval catheter with an expansile tip and a braided support structure that can expand to accommodate larger clots, featuring a proximal elongate shaft, a distal tip section with a collapsible and deployable configuration, and polymer jackets for added flexibility and atraumatic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If a larger inner diameter catheter is used to accommodate larger clots, then clot retrieval capacity is improved, but the catheter requires a larger guide or sheath which necessitates a larger femoral access hole
Solution Approach 1:
The catheter employs an expandable tip that transitions from a compressed delivery configuration to an expanded operational configuration. The tip can expand to a larger diameter (e.g., from 6Fr to 8Fr or larger) at the distal end while maintaining a smaller profile during delivery through standard guides and sheaths. This dynamic size change allows the catheter to accommodate larger clots without requiring larger access holes.
Solution Approach 2:
The expandable tip is designed to be nested within the catheter body during delivery, similar to a nested doll structure. The tip can be compressed within the catheter shaft and then deployed outward at the target site, allowing the system to achieve a larger effective diameter without increasing the delivery profile.
2Ease of manufacture
If a fixed tip size is used, then manufacturing is simplified, but aspiration efficiency is reduced because suction draws from proximal fluid rather than clot material
Solution Approach 1:
The tip transitions from a fixed size to a dynamically expandable size. When expanded, the tip creates a funnel shape that directs aspiration flow preferentially through the clot material rather than drawing from proximal fluid, thereby improving aspiration efficiency and productivity.
3Area of moving object
If a larger expandable tip is used to accommodate larger clots, then clot retrieval capacity is improved, but the catheter may become lodged in the vessel or cause trauma during navigation
Solution Approach 1:
The tip dynamically changes size - small during navigation to avoid trauma and lodging, then large when expanded at the target site for effective clot retrieval. This temporal separation of size requirements eliminates the harm associated with large fixed tips during navigation.
Solution Approach 2:
The tip is pre-compressed to a small profile before navigation, allowing safe passage through tortuous vessels. The expansion to a large diameter occurs only after successful delivery to the target site, preventing trauma during the navigation phase.
4Strength
If the braid is made stiffer to provide hoop strength for aspiration, then resistance to aspiration collapse is improved, but flexibility and deliverability through tortuous vessels deteriorates
Solution Approach 1:
The braid structure has different properties in different locations - the proximal shaft maintains a standard configuration for flexibility, while the distal tip section has a modified braid pattern optimized for expansion and hoop strength when engaged with clots. This local differentiation allows both flexibility during navigation and strength during aspiration.
Solution Approach 2:
The catheter is divided into segments with different braid characteristics - the shaft portion prioritizes flexibility for navigation, while the tip portion prioritizes hoop strength for aspiration. This segmentation allows each section to be optimized for its specific function without compromising the other.
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 catheter effectively navigates tortuous vessels, reduces clot fragmentation, and enhances aspiration efficiency by providing a larger lumen and distal mouth for clot retrieval, while maintaining sufficient hoop strength and flexibility to resist aspiration forces.
Implementation Method 1
an expansile portion (213) having a collapsed delivery configuration and an expanded deployed configuration
Implementation Method 2
a first plurality of wire braided segments (120)... a second plurality of wire braided segments (220) comprising circumferential rings of cells (226)
Data Source
AI summary
The designs and methods disclosed herein are for a clot retrieval catheter with a large bore shaft and a distal braid-supported tip that is expandable to a diameter larger than the outer sheath through which it is delivered.