Catheter Reinforcing Layer Variable Braid Configuration
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Solution Overview
Problem
Existing catheters face challenges in achieving a balanced combination of flexibility and columnar strength due to discontinuities and additional stiffness at transitions between braided and coiled support layers, which affect steerability and kink-resistance, especially in navigating tortuous vascular paths.
Innovation Solution
A catheter design featuring a reinforcing layer with a continuous plurality of filaments transitioning from a full complement braid to a partial complement braid configuration, encased in a polymeric bonding layer, allowing for variable stiffness along the catheter length without the need for additional manufacturing steps or material overlaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a braided support layer is used to provide columnar strength and kink resistance, then the catheter gains sufficient rigidity to be pushed through the vasculature, but the catheter becomes too stiff to follow winding vascular paths and transmit rotational inputs
Solution Approach 1:
The catheter incorporates different support layer configurations at different locations along its length. The proximal section contains a braided support layer providing high columnar strength for pushability, while the distal section contains a coiled support layer providing flexibility for navigation. This local differentiation allows each section to optimize its properties for its specific functional requirements.
Solution Approach 2:
The support layer is divided into distinct segments: a braided portion and a coiled portion, separated by a transition region. This segmentation allows the catheter to combine the advantages of both braided (strength, kink resistance) and coiled (flexibility, low bending stiffness) configurations without the drawbacks of overlapping or abutting transitions.
2Strength
If braided and coiled support layers are joined by overlapping or abutting transitions, then both types of reinforcement are provided, but additional manufacturing steps are required and discontinuities create undesirable thickness and stiffness variations
Solution Approach 1:
The braided support layer and coiled support layer are merged into a single continuous structure through a transition region where the braid pattern naturally transforms into a coil pattern. This integration eliminates the need for separate joining operations, overlapping, or abutting transitions, thereby reducing manufacturing complexity while maintaining continuous reinforcement.
Solution Approach 2:
The support layer is constructed as a continuous structure without breaks, overlaps, or abutting joints. The transition from braided to coiled configuration occurs through a continuous transformation process, ensuring uninterrupted reinforcement along the catheter length and eliminating discontinuities that would cause thickness and stiffness variations.
3Adaptability or versatility
If the braid angle or pick count per inch is changed to limit stiffness in certain areas, then flexibility is improved, but the changes are gradual and do not allow abrupt changes in stiffness along the catheter
Solution Approach 1:
The catheter utilizes fundamental changes in support layer configuration (from braided to coiled) rather than gradual adjustments of braid parameters. This dramatic parameter change enables abrupt transitions in stiffness along the catheter length, allowing precise control over where flexibility is enhanced without requiring gradual parameter modifications.
Data Source
AI summary
A catheter includes an elongate member having a braided reinforcing layer encased within a polymeric bonding layer. The reinforcing layer comprises a plurality of continuous filaments that transform from a full complement braid configuration to a partial complement braid configuration in a least one location along the catheter. Also disclosed is a method of manufacturing a braided elongate member including providing a core, forming at least one full complement braid portion with a plurality of filaments and forming at least one partial complement braid portion with a portion of the same plurality of filaments.