Multifilar Cable Catheter Shaft Design for Pushability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current medical catheters for endovascular procedures face challenges in achieving optimal pushability and trackability due to issues with material uniformity, flexibility, and structural integrity, leading to potential kinking and friction problems, especially in short-wire configurations.
Innovation Solution
A multifilar cable tubing construction for the catheter shaft, which is adaptable for both short-wire and long-wire configurations, providing consistent pushability and trackability through a tapered design and coatings that enhance flexibility and reduce friction, while maintaining structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a catheter shaft is made from multiple materials along the shaft length to achieve varying flexibility and stiffness, then pushability and trackability are improved, but device complexity and manufacturing cost increase due to multiple material junctions and specialized connection means
Solution Approach 1:
The catheter shaft incorporates a stiffening wire within an interwoven braid structure, creating localized reinforcement at specific positions along the shaft. This allows different sections of the shaft to have different mechanical properties (stiffness and flexibility) without requiring multiple separate materials, thereby achieving varying pushability and trackability while maintaining structural simplicity
Solution Approach 2:
The shaft is constructed as a composite structure combining an interwoven braid material with an embedded stiffening wire. This composite design integrates multiple functional properties (flexibility from the braid, stiffness from the wire) into a single homogeneous structure that eliminates the need for separate material junctions and specialized connections
2Strength
If a stiffening wire is disposed through a significant portion of the catheter shaft to enhance stiffness, then pushability is improved, but the likelihood of structural failure at junctions increases
Solution Approach 1:
The stiffening wire is integrated within the interwoven braid structure rather than being attached as a separate component. This merging of the wire with the braid creates a unified structure where the wire and braid work together as a single system, eliminating separate junctions and reducing the risk of structural failure at connection points
Solution Approach 2:
The stiffening wire is pre-positioned and embedded within the braid structure during manufacturing, ensuring proper alignment and integration before the catheter is assembled. This preliminary integration prevents misalignment and reduces stress concentrations that could lead to structural failure during use
3Ease of operation
If the wire guide lumen is shortened to facilitate easier exchange operations, then ease of operation is improved, but the structural integrity and support of the catheter shaft are reduced
Solution Approach 1:
The stiffening wire is positioned to extend through specific critical sections of the shaft where structural support is most needed, rather than requiring the wire guide lumen to extend the full length of the catheter. This localized reinforcement maintains shaft integrity while allowing for a shorter, more exchange-friendly wire guide lumen configuration
Solution Approach 2:
The interwoven braid with embedded stiffening wire creates a self-supporting shaft structure that maintains its structural integrity independently of the wire guide lumen length. This composite construction provides the necessary rigidity and support even when the wire guide lumen is shortened for easier exchange operations
Data Source
Figure 1A~1B
Figure 2~3B
Figure 4A~4B
AI summary
A balloon catheter device (400) of the present invention includes an elongate catheter shaft (401) comprising multifilar cable tubing having a proximal portion and a distal portion. The proximal portion includes a coating that allows the shaft to provide a patent fluid passage, and a part of the distal portion inside a balloon (406) 5 may be uncoated or otherwise open to the balloon lumen, allowing for passage of fluid through the shaft into the balloon lumen.