Balloon Catheter Intermediate Shaft Flexibility for Smooth Deflation
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Solution Overview
Problem
Existing balloon catheters face difficulties in deflating smoothly due to the lengthening of the distal shaft, which narrows the gap between the distal shaft and the inner shaft, preventing the discharge of operation fluid.
Innovation Solution
A balloon catheter design featuring a more flexible intermediate shaft than the distal shaft, with a non-fixing portion extending to the distal end side relative to a fixing portion in the overlapped area, allowing the intermediate shaft to lengthen preferentially and preventing the distal shaft from lengthening, thus maintaining a larger gap for fluid discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the distal shaft and intermediate shaft are made more flexible than the proximal shaft to improve catheter navigation, then the catheter can be pulled back when the balloon is caught by a stenosed portion, but the distal shaft lengthens and the inner diameter decreases, narrowing the gap between the distal shaft and inner shaft and preventing operation fluid discharge
Solution Approach 1:
The catheter shaft is divided into three distinct segments: proximal shaft, intermediate shaft, and distal shaft. Each segment has different flexibility characteristics, with the intermediate shaft being the most flexible. This segmentation allows the intermediate shaft to absorb lengthening during pullback while preventing distal shaft lengthening that would narrow the fluid discharge gap.
Solution Approach 2:
Different portions of the catheter shaft are assigned different mechanical properties. The intermediate shaft is specifically designed to be more flexible than both the proximal and distal shafts, creating a localized flexibility gradient. This local quality differentiation ensures that when pullback force is applied, the intermediate shaft preferentially lengthens while maintaining the rigidity of the distal shaft to preserve the fluid discharge gap.
2Reliability
If the intermediate shaft is made more flexible than the distal shaft with a non-fixing portion extending to the distal end side, then the intermediate shaft can lengthen preferentially during pullback, but this increases the complexity of the shaft structure
Solution Approach 1:
The intermediate shaft is nested within the distal shaft, with the intermediate shaft's non-fixing portion extending to the distal end side relative to the fixing portion. This nested configuration allows the intermediate shaft to lengthen preferentially during pullback while the distal shaft maintains its position and inner diameter, preserving the fluid discharge gap without requiring complex external mechanisms.
3Ease of operation
If the fixing portion is positioned at the proximal end of the intermediate shaft and the non-fixing portion extends to the distal end side, then substantially the entirety of the intermediate shaft can lengthen during pullback, but this reduces the rigidity of the distal shaft assembly
Solution Approach 1:
The intermediate shaft is designed with dynamic lengthening capability through its non-fixing portion that extends to the distal end side relative to the fixing portion. This allows the intermediate shaft to dynamically adjust its length during pullback operations, absorbing the lengthening strain while the distal shaft maintains its structural rigidity for effective fluid discharge.
Data Source
AI summary
Provided is a balloon catheter in which a balloon can smoothly deflate even when being pulled. A balloon catheter includes a balloon that can inflate and deflate, a hollow distal shaft that communicates with the balloon and in which an inner shaft is inwardly provided, a hollow intermediate shaft that is connected to a proximal end side of the distal shaft so as to communicate therewith, a hollow proximal shaft that overlaps a proximal end side of the intermediate shaft so as to be connected thereto and that communicates with the intermediate shaft, and a reinforcement body that extends from the proximal shaft to the distal shaft and is fixed to the proximal shaft, in which the intermediate shaft is more flexible than the distal shaft, and in an overlapped portion in which the intermediate shaft and the proximal shaft overlap each other, a non-fixing portion in which the intermediate shaft and the proximal shaft overlap each other without being fixed extends to a distal end side relative to a fixing portion in which the intermediate shaft is fixed to the proximal shaft.