Expandable Funnel Catheter Tip for Clot Retrieval
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Solution Overview
Problem
Conventional balloon guide catheters have a 'dead space' distal to the balloon where clot fragments can lodge, and they induce high shear stress on clots during retrieval, leading to potential occlusions and patient harm.
Innovation Solution
A catheter with an expandable distal tip featuring a funnel-shaped balloon that minimizes dead space and reduces shear stress by inflating to contact the vessel wall, stabilizing the catheter, and optimizing the clot-catheter interface, using materials like thermoplastic polyurethane elastomers for compliance and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional balloon guide catheter is used with a distal tip and balloon attachment method, then the catheter can be manufactured with standard techniques, but dead space is created distal to the balloon where clot fragments can lodge
Solution Approach 1:
The catheter tip is designed to be expandable from a compressed delivery configuration to an expanded configuration. The distal tip includes an expandable portion with a flare angle that increases when expanded, dynamically changing the geometry to eliminate dead space while maintaining manufacturability through controlled expansion during the procedure
Solution Approach 2:
The catheter utilizes changes in geometric parameters (flare angle, tip diameter) through expansion to transform the dead space-free configuration. The expandable tip changes its physical state from compressed to expanded, altering the effective geometry to prevent clot fragment lodging while preserving manufacturing feasibility
2Productivity
If clot is withdrawn into the catheter with a conventional sharp tip, then clot retrieval can be achieved, but high shear stress is induced causing clot fragmentation
Solution Approach 1:
The expandable tip dynamically adjusts its flare angle during the procedure. In the expanded configuration, the increased flare angle creates a more gradual transition zone that reduces shear stress on the clot during withdrawal, while still enabling effective clot retrieval through the catheter lumen
Solution Approach 2:
The expandable tip creates a curved, funnel-like geometry with a gradual flare angle when expanded. This curved transition zone replaces the sharp angular transition of conventional tips, distributing shear forces more evenly and reducing clot fragmentation during the withdrawal process
3Reliability
If the catheter tip is expanded to contact the vessel wall, then flow restriction is improved for safer clot retrieval, but the catheter structure becomes more complex
Solution Approach 1:
The catheter is segmented into distinct functional zones: a compliant distal tip portion for flow restriction and clot interaction, and a more rigid proximal shaft for structural support. This segmentation allows the complex flow restriction function to be localized to the tip while maintaining overall structural simplicity
Solution Approach 2:
The distal tip is constructed from compliant, flexible materials that can expand and contact the vessel wall. This flexible shell approach enables effective flow restriction through material compliance rather than complex mechanical structures, simplifying the overall device design while maintaining reliability
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 solution effectively retrieves clots without fragment loss, reducing the risk of occlusions and ensuring safe blood flow restoration by eliminating dead space and minimizing shear stress during clot withdrawal.
Implementation Method 1
an inflatable expansile member at the distal end, the expansile member being inflatable from a collapsed delivery configuration to an expanded configuration
Implementation Method 2
in the expanded configuration, the expansile member extends radially outwardly from the shaft at the distalmost tip of the shaft to define a mouth
Implementation Method 3
The elongate shaft comprises a first inner lumen through which other catheters or components may be passed and through which clot may be aspirated
Implementation Method 4
through which clot may be aspirated
Data Source
AI summary
A clot capture catheter comprises an elongate tubular shaft having a proximal end, a distal end and an inflatable expansile member at the distal end. The expansile member is inflatable from a collapsed delivery configuration to an expanded configuration. In the expanded configuration, the expansile member extends to define a funnel shape having an enlarged distal clot entry mouth at the distal-most end of the catheter. In the expanded configuration, the expansile member may extend distally beyond the distalmost tip of the shaft. The expansile member may be integral with the distal tip of the catheter shaft.