Balloon Catheter Core Wire Fixation for Pushability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Rapid exchange type balloon catheters face issues with pushability and kinking when inserted into blood vessels, especially in curved vessels, due to insufficient core wire fixation and high stiffness, making them unsuitable for crossover approaches in treating peripheral arterial disease.
Innovation Solution
A balloon catheter design featuring a resin outer shaft with a core wire having a straight and taper portion, where the straight portion is press-fitted between the outer shaft and inner tube, providing partial fixation and allowing flexibility, and the core wire is fixed at the guide wire port position to enhance pushability and prevent kinking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the core wire is firmly fixed to the inner peripheral surface of the distal end side shaft, then the pushing force can be reliably transmitted and good pushability can be exhibited, but the bending stiffness of the distal end side shaft becomes too high and flexibility is significantly impaired
Solution Approach 1:
The core wire is divided into multiple straight portions with different lengths, and only the distal end straight portion is press-fitted between the outer shaft and inner tube. This segmentation allows the distal end to have fixed core wire for pushability while proximal portions maintain flexibility for navigating curved vessels.
Solution Approach 2:
The core wire fixation is applied locally only to the distal end straight portion rather than the entire core wire. This local quality approach provides sufficient pushability at the critical distal end while maintaining overall flexibility of the catheter for navigating curved blood vessels.
2Adaptability or versatility
If the core wire is not fixed to the inner peripheral surface of the outer shaft, then the flexibility is maintained, but sufficient pushability cannot be exhibited and the core wire moves in the axial direction
Solution Approach 1:
The core wire is segmented into multiple straight portions, and only the distal end portion is press-fitted to the outer shaft. This selective segmentation provides axial stability for pushability at the distal end while maintaining flexibility in other sections.
Solution Approach 2:
Instead of fixing the entire core wire length, only a partial length (the distal end straight portion) is press-fitted between the outer shaft and inner tube. This partial action is sufficient to provide the needed pushability without excessive fixation that would impair flexibility.
3Stability of the object's composition
If a metal tube is used for the rear end side shaft to increase stiffness, then kinking can be prevented, but the balloon catheter cannot be smoothly inserted into curved blood vessels
Solution Approach 1:
The material of the outer shaft is changed from metal to resin, fundamentally altering the stiffness parameter. This allows the shaft to be flexible enough for curved vessel navigation while the press-fitted core wire provides sufficient structural support to prevent kinking.
Solution Approach 2:
The outer shaft is constructed as a composite structure with a resin tube and a press-fitted core wire. This composite design combines the flexibility of resin with the stiffness-providing capability of the core wire, achieving both smooth insertion and kinking prevention.
Data Source
Figure 1
Figure 2(a)~2(e)
AI summary
An object of the present invention is to provide a balloon catheter that has excellent pushability upon insertion into a blood vessel, and in which kinking of an outer shaft on the rear end side of a position where a guide wire port is formed can be reliably prevented, and that can be smoothly inserted even into a curved blood vessel. The balloon catheter of the present invention includes an outer shaft (10) composed of a resin tube, a balloon (30), a hub (60), an inner tube (40) and a core wire (50). The rear end side of the straight portion (51) of the core wire (50) is fixed to the inner peripheral surface of the outer shaft (10) on the rear end side of the position where a guide wire port is formed, and the distal end side of the straight portion (51) of the core wire (50) is press-fitted between the inner peripheral surface of the outer shaft (10) and the outer peripheral surface of the inner tube (40).