Multilayer Catheter Soft Tip with Non-Tacky Inner Layer
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Solution Overview
Problem
Conventional intravascular catheters face challenges with soft tip materials that tend to frictionally engage or stick to guidewires, making it difficult to advance or retract the catheter, while also requiring minimal stiffness to track through tortuous vasculature without structural failure or kinking.
Innovation Solution
A balloon catheter with a soft distal tip member featuring a non-tacky inner layer and a flexible outer layer, both thermally bondable to the catheter balloon, providing a securely bonded yet flexible and soft distal end with a non-tacky surface to prevent guidewire locking and ensure high pull strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If soft tip materials are used to prevent vessel injury, then the catheter becomes more flexible and atraumatic, but the materials tend to frictionally engage or stick to guidewires, making it difficult to advance or retract the catheter
Solution Approach 1:
The soft tip is divided into multiple layers with different properties: an inner layer that provides flexibility and vessel protection, and an outer layer that reduces friction with the guidewire, allowing the tip to be segmented into functional zones
Solution Approach 2:
Different portions of the soft tip are given different material properties - the inner layer has high flexibility for vessel protection while the outer layer has low friction characteristics for guidewire mobility, creating local quality variations within the single component
2Force
If the catheter shaft is made stiff to transmit force for positioning, then force transmission improves, but the catheter loses flexibility to track over guidewire through tortuous vasculature
Solution Approach 1:
The catheter is segmented into a stiff shaft portion for force transmission and a soft tip portion for tracking, allowing each segment to perform its specialized function without compromise
Solution Approach 2:
Different sections of the catheter have different stiffness properties - the shaft is stiff for force transmission while the distal tip is soft and flexible for navigating tortuous vasculature, creating local quality variations along the catheter length
3Adaptability or versatility
If the distal tip is made very soft to track through tortuous vasculature, then tracking ability improves, but the catheter may suffer structural failure or kinking
Solution Approach 1:
The tip is segmented into multiple layers where the inner layer provides softness for tracking and the outer layer provides structural reinforcement, preventing kinking while maintaining flexibility
Solution Approach 2:
The soft tip uses composite material construction with an inner soft layer and an outer layer with higher structural properties, combining the benefits of both materials to achieve both flexibility and strength
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 catheter achieves enhanced processability and deliverability with a flexible, atraumatic distal end that prevents guidewire locking, while maintaining high pull strength and integrity, improving tracking and deployment during medical procedures.
Implementation Method 1
an inner layer formed of a polymeric material having a coefficient of friction and surface energy which are relatively low, such that the inner layer has a lubricious, non-polar inner surface repulsive to polar liquids
Implementation Method 2
a first layer which is fusion bondable to another catheter component such as the skirt of an inflatable balloon and a second layer which is adjacent the first layer having a melting point greater than the first layer so that the multilayered member of the catheter is not deformed when the other catheter component is fusion bonded to the first layer of the multilayered member
Data Source
Figure 1~4
Figure 5a~6
AI summary
A balloon catheter (10) having a soft distal tip member (15) having a non-tacky inner (liner) layer material (33) and a soft flexible outer layer material (34), with both materials being readily thermally bondable to the catheter balloon.