Variable Cross-Section Catheter Braid Wire for Kink Resistance
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Solution Overview
Problem
Existing catheter designs lack a smooth transition from a stiff proximal portion to a flexible distal portion, leading to potential kinking, buckling, and reduced trackability, which hinders their effectiveness in intravascular medical procedures.
Innovation Solution
A catheter braid with varying cross-section shapes and compositions, transitioning from a rectangular shape at the proximal portion to a circular shape at the distal portion, ensuring a smooth transition and maintaining axial stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the catheter uses a uniform cross-section shape throughout its length, then the manufacturing process is simpler, but the catheter cannot provide both axial stiffness at the proximal portion and flexibility at the distal portion
Solution Approach 1:
The catheter braid incorporates wire segments with different cross-section shapes at different locations along its length. The proximal portion uses wire segments with a first cross-section shape that provides axial stiffness, while the distal portion uses wire segments with a second cross-section shape that provides flexibility. This local differentiation allows the catheter to have varying mechanical properties along its length, resolving the contradiction between manufacturing simplicity and stiffness gradient capability.
Solution Approach 2:
The catheter braid is divided into multiple segments along its length, with each segment containing wire segments of a specific cross-section shape. The transition region contains a mixture of both first and second cross-section shapes. This segmentation approach allows independent optimization of mechanical properties in different regions while providing a gradual transition, balancing manufacturing complexity with functional requirements.
2Ease of manufacture
If the catheter has an abrupt transition from stiff proximal portion to flexible distal portion, then the manufacturing process is simpler, but the catheter is prone to kinking and buckling
Solution Approach 1:
The catheter braid implements a dynamic, gradual transition of wire segment cross-section shapes along its length rather than an abrupt change. In the transition region, the proportion of first and second cross-section shapes varies continuously, creating a gradient in mechanical properties. This dynamic transition distributes stress more evenly, preventing stress concentrations that would lead to kinking and buckling, while still being manufacturable through controlled braiding processes.
3Ease of operation
If the catheter uses wire segments with varying cross-section shapes to provide smooth transition, then the catheter flexibility and trackability are improved, but the manufacturing complexity increases
Solution Approach 1:
The catheter braid varies the cross-section shape parameter of wire segments along its length to achieve the desired mechanical properties. By controlling the shape parameter (e.g., circular vs. rectangular cross-section) and the proportion of different shapes in the transition region, the braid provides a smooth gradient in stiffness that improves trackability. This parameter-based approach allows systematic control of mechanical properties while maintaining a relatively simple braided structure that is feasible to manufacture.
Data Source
Figure 1A
Figure 1B
Figure 1C~1D
AI summary
Catheter braid (100) including wire segments (108) with varying cross-section shapes. Wire segments at a proximal portion (102) of the braid can have a substantially rectangular cross-section shape, while wire segments at a distal portion (106) of the braid can have a substantially circular cross-section shape. The cross-section shape can gradually transition from rectangular to circular along the length of the braid. The catheter braid can include wire segments having an outer core (210) and an inner core (212). The inner core at the proximal section of the braid can have a substantially rectangular cross-section shape, while the inner core at the distal portion of the braid can have a substantially circular cross-section shape. The cross-section shape of the inner core can gradually transition from rectangular to the circular to provide a smooth transition.