Flexible Catheter Support Tube With Expandable Tip for Clot Aspiration
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Solution Overview
Problem
Conventional aspiration catheters face challenges in navigating the small, tortuous neurovascular system due to issues with flexibility, stiffness, and aspiration efficiency, leading to reduced clot removal success and potential clot lodging.
Innovation Solution
A clot retrieval catheter with a flexible support tube and an expandable tip designed to navigate tortuous vessels, featuring a tubular body with axial spines and loop ribs, allowing for local flow restriction and improved aspiration efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the catheter is made highly flexible to navigate tortuous vessels, then trackability is improved, but the diameter is reduced and incapable of generating the required suction force
Solution Approach 1:
The catheter is divided into distinct sections with different stiffness characteristics. The proximal shaft is made highly flexible for navigation, while the distal portion including the mouth is made stiffer to generate suction force and maintain structural integrity during clot retrieval.
Solution Approach 2:
Different portions of the catheter are assigned different mechanical properties tailored to their specific functions. The distal section has increased stiffness and structural support to generate aspiration force, while the proximal section maintains high flexibility for vessel navigation.
2Productivity
If the catheter mouth is made large to achieve maximum aspiration efficiency, then clot retrieval capability is improved, but the catheter requires expandable members or separate suction extensions that lack flexibility to navigate the neurovascular system
Solution Approach 1:
The catheter with its large distal mouth is designed to be nested within a delivery system consisting of an outer catheter and intermediate catheter. This allows the large-mouthed catheter to be delivered through small access sheaths while maintaining its full aspiration capability at the target site.
Solution Approach 2:
The catheter transitions from a compressed, flexible delivery configuration to an expanded, structurally supportive working configuration at the target site. This dynamic transformation allows the catheter to navigate tortuous vessels in a flexible state and then provide sufficient suction force when deployed.
3Force
If the catheter has abrupt stiffness or geometric changes to provide axial stiffness for smooth advancement, then pushability is improved, but trackability is hindered and stress concentrations are introduced
Solution Approach 1:
The catheter employs gradual transitions in stiffness parameters along its length rather than abrupt changes. The distal portion gradually increases in stiffness to provide axial support, while the proximal portion remains flexible for navigation, eliminating stress concentrations and preventing kinking.
4Device complexity
If traditional fixed-mouth catheters are used for aspiration, then device simplicity is maintained, but aspiration efficiency is reduced as significant flow comes from vessel fluid proximal to the tip where there is no clot
Solution Approach 1:
The catheter is pre-positioned with its large distal mouth at the target site before aspiration begins. The mouth is deployed to the expanded configuration at the occlusion site, ensuring that aspiration flow is directed through the clot from the beginning of the procedure, maximizing retrieval efficiency.
Data Source
AI summary
A clot retrieval catheter can have a tailored, highly flexible body section capable of navigating tortuous routes and an expandable tip for local flow restriction/arrest. The body can be a support tube of struts with a plurality of ribs and one or more axial spines. The support tube can also be a tubular section with a pattern of radial slots to increase flexibility while inhibiting kinking and binding. The ribs and spines can have strut widths which vary along the length of the support tube or can have curves with a non-planar cross section. The ribs can be formed such that they can move when subjected to the loads of a thrombectomy procedure. The structure of the support tube can also be a braided or woven pattern of strands. The support tube can also have a polymer jacket or membrane disposed around at least a portion of the structure.