Balloon Catheter Linear Member Dynamics for Vessel Crossability
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Solution Overview
Problem
The existing balloon catheters face challenges in crossability due to the larger outer diameter of the fixed cone-shaped portion at the distal end of the inner tube, even in a deflated state, which hinders their ability to navigate through constricted blood vessels effectively.
Innovation Solution
A balloon catheter design featuring a balloon/shaft assembly with a linear member that includes a hard portion and a flexible portion, where the linear member is mounted on the balloon/shaft assembly at positions further towards the distal and proximal ends than the inflatable region, allowing it to extend radially and improve crossability by separating from the inner tube during inflation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed cone-shaped portion with large outer diameter is used at the distal end of the inner tube, then the linear member can be supported and extended properly, but the catheter's crossability through constricted blood vessels deteriorates
Solution Approach 1:
The linear member is designed with a flexible portion that allows it to dynamically change its configuration. In the deflated state, the linear member remains close to the inner tube with a compact profile enabling crossability. During balloon inflation, the linear member extends radially outward to provide structural support and engage with the vessel wall, transforming from a compact to an extended state based on operational requirements.
Solution Approach 2:
The linear member is positioned to nest along the outer periphery of the inner tube in the deflated state, with its distal end extending beyond the balloon's distal end and its proximal end positioned within the catheter shaft. This nested configuration minimizes the overall outer diameter of the catheter assembly, improving crossability through constricted vessels while maintaining the capability for radial extension when needed.
2Length of moving object
If the linear member is positioned close to the inner tube in deflated state, then crossability improves, but the ability to act on constricted vessel areas during inflation may be reduced
Solution Approach 1:
The linear member transitions from a retracted position during navigation to an extended radial position during treatment. The flexible portion enables this dynamic transformation, allowing the linear member to reach outward and apply sufficient force to constricted vessel areas when the balloon is inflated, while maintaining a low-profile configuration during delivery.
Solution Approach 2:
The linear member is pre-positioned along the outer periphery of the inner tube with its flexible portion oriented toward the balloon's outer surface. This preliminary positioning ensures that when inflation occurs, the linear member is already in place to extend radially and immediately engage with the constricted vessel wall, maximizing the effectiveness of the dilation process.
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 design enhances the catheter's ability to navigate through constricted blood vessels by allowing the hard portion to act on the vessel's constricted areas without obstructing the inflation process, improving the catheter's ability to dilate effectively and reducing the force required for navigation.
Implementation Method 1
The balloon has an inflatable region configured to inflate outward in a radial direction around the catheter shaft
Implementation Method 2
The flexible portion is extendable and has a lower hardness than the hard portion
Data Source
AI summary
A balloon catheter includes a balloon/shaft assembly and a linear member. The balloon/shaft assembly includes a catheter shaft extending from a proximal end to a distal end and a balloon connected to the catheter shaft. The linear member straddles an inflatable region of the balloon and is mounted on the balloon/shaft assembly. The linear member includes a hard portion and a flexible portion. The hard portion includes at least an outer portion disposed on an opposite side to an inner portion facing the inflatable region, of a portion disposed along an outer peripheral surface of the inflatable region in an inflated state. The flexible portion is a portion other than the hard portion. The flexible portion is extendable and has a lower hardness than the hard portion.