Expandable Braid-Supported Catheter Tip for Atraumatic Clot Retrieval
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Solution Overview
Problem
Existing clot retrieval catheters face challenges in navigating tortuous vessels, are often too large in profile, lack deliverability and flexibility, and are inefficient at removing clots due to fixed tips and insufficient aspiration, leading to clot lodging and shearing, especially in small-diameter neurovascular beds.
Innovation Solution
A super-bore clot retrieval catheter with a collapsible and expandable tip design featuring a braid-supported structure, including a proximal elongate shaft and a distal tip section with varying braid patterns and polymeric jackets, allowing for self-expansion and atraumatic navigation through vessels, while maintaining flexibility and resistance to aspiration forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional aspiration catheters are used with fixed tips and small inner diameters, then the device can be delivered through standard sheaths and guides, but the catheter cannot efficiently remove large clots and requires compression that leads to clot shearing and lodging
Solution Approach 1:
The catheter tip is designed to be dynamically expandable from a compressed delivery configuration to an expanded working configuration. The tip expands radially to increase the inner diameter from approximately 0.068-0.074 inches to a larger diameter, allowing large clots to be captured without compression. This dynamic transformation resolves the contradiction by enabling efficient clot removal while maintaining compatibility with standard delivery systems.
Solution Approach 2:
The expandable tip is nested within the catheter shaft during delivery, allowing the entire device to pass through standard sheaths and guides. Once at the target site, the tip is deployed outward from the shaft, creating a funnel-shaped expansion that captures clots effectively. This nesting principle allows the catheter to have a small delivery profile while providing a large working lumen for clot removal.
2Adaptability or versatility
If the catheter tip is made flexible and collapsible for delivery, then the device can navigate tortuous vessels, but the tip may lack the structural support needed to resist aspiration forces and maintain shape during clot retrieval
Solution Approach 1:
The catheter employs different braid patterns in different sections to provide locally optimized properties. The proximal shaft uses a first braid pattern providing flexibility for navigation, while the distal tip uses a second braid pattern with different characteristics to provide structural support and resistance to aspiration forces when expanded. This local differentiation resolves the contradiction between flexibility for navigation and strength for clot retrieval.
Solution Approach 2:
The catheter construction combines multiple materials including braided reinforcement layers, polymeric jackets, and low-friction liners. The braided sections provide structural strength while the polymeric materials provide flexibility and trauma prevention. This composite construction allows the tip to be both flexible enough for delivery and strong enough to resist aspiration forces during operation.
3Productivity
If a larger bore catheter is used to accommodate large clots, then clot capture efficiency improves, but the device becomes too large for standard sheaths and guides requiring larger access holes
Solution Approach 1:
The catheter outer diameter is dynamically variable through the expandable tip mechanism. During delivery, the tip is compressed to a small diameter that fits within standard 8Fr guide/6Fr sheath combinations. At the target site, the tip expands radially to create a large inner diameter for efficient clot capture. This dynamic size transformation resolves the contradiction between large clot capture capability and compatibility with standard access systems.
4Strength
If the catheter uses a braid-supported structure for strength, then the tip can resist aspiration forces, but the braid may increase friction and trauma to vessel walls during navigation
Solution Approach 1:
The braid-supported structure is localized to specific sections where structural strength is needed, while other sections use softer, more compliant materials. The braided reinforcement provides aspiration force resistance at the tip, while the polymeric jackets and low-friction liners in navigation sections minimize vessel wall trauma. This local differentiation resolves the contradiction between strength and trauma prevention.
Solution Approach 2:
The catheter incorporates polymeric jackets and low-friction liner materials that provide a smooth, flexible interface with vessel walls during navigation, reducing trauma. The braid-supported structure is positioned internally to provide strength without directly contacting the vessel wall. This layered construction resolves the contradiction between structural strength and minimal vessel trauma.
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 design enables efficient clot removal by minimizing friction and deformation, navigating tortuous vasculature, and ensuring complete aspiration of clots without shearing, even in small-diameter vessels, while maintaining atraumatic properties and compatibility with standard sheaths and guides.
Implementation Method 1
a distal tip with an expandable, collapsible, self-expanding braided support structure and outer polymeric jacket
Implementation Method 2
The elongate shaft can have a low friction inner liner
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. The shaft can have a plurality of supporting braids fixed distally to a radiopaque marker band. The tip can have another plurality of supporting braids fixed proximally to the marker band and a decreasing braid angle distally so that the tip can be heat set to an expanded funnel shape. The wires of the tip braids can follow one spiral direction distally and then invert proximally back on themselves to form the other spiral direction of the braid. This inversion of the wires results in atraumatic distal hoops at the distal termination of the braid. Designs can further have spines capable of resisting elongation of the catheter shaft during a procedure.