Balloon Catheter Crystallinity Gradients for Flexible Vascular Navigation
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Solution Overview
Problem
Existing balloon catheters face challenges in achieving sufficient flexibility to navigate tortuous and calcified segments in blood vessels while maintaining structural integrity and reducing stress on the body.
Innovation Solution
A medical elongated body with a catheter shaft and a distal member fused together, where the crystallinity of the distal portions is less than 40%, and the inner layer extends in an arc outward and the outer layer inward in the radial direction, enhancing flexibility and bonding strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the catheter shaft is made with high crystallinity material to maintain structural integrity, then strength is improved, but flexibility deteriorates
Solution Approach 1:
The catheter shaft is constructed with multiple layers having different crystallinity characteristics. The inner layer has lower crystallinity (30-60%) providing flexibility, while the outer layer has higher crystallinity (40-80%) providing strength. This local differentiation of material properties resolves the contradiction between overall structural integrity and local flexibility requirements.
Solution Approach 2:
The catheter shaft uses a composite structure with an inner layer and outer layer made of different polyamide materials with distinct crystallinity ranges. This composite material approach allows the shaft to simultaneously achieve the flexibility needed for navigating tortuous vessels and the strength required for structural integrity.
2Strength
If the distal member is made with high crystallinity material to maintain structural integrity, then strength is improved, but flexibility deteriorates
Solution Approach 1:
The distal member is designed with a specific crystallinity range (20-50%) that is lower than conventional materials, creating a locally optimized structure for flexibility at the distal end where navigation through tortuous segments is most critical, while maintaining sufficient strength through the fused connection with the shaft.
3Ease of operation
If the crystallinity of the distal portion is reduced to improve flexibility, then ease of operation is improved, but bonding strength deteriorates
Solution Approach 1:
The inner layer of the catheter shaft is designed with a crystallinity gradient, where the distal portion has lower crystallinity (30-60%) for flexibility, while the proximal portion has higher crystallinity for bonding strength. This spatial variation in material properties allows both flexibility and strong bonding to coexist.
Solution Approach 2:
The composite structure with inner and outer layers of different crystallinity provides a solution where the inner layer's lower crystallinity ensures flexibility and ease of operation, while the outer layer's higher crystallinity compensates for bonding strength requirements at the fusion interface.
Data Source
AI summary
A medical elongated body or a balloon catheter with high flexibility. The medical elongated body including: a catheter shaft that extends in an axial direction; and a distal member that is fused to a distal side of the catheter shaft, in which a crystallinity of each of a distal portion of the catheter shaft and a proximal portion of the distal member is less than 40%.