Catheter Tip Spring Element for Flexibility and Rigidity
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Solution Overview
Problem
Current endovascular catheter tips face challenges in balancing longitudinal flexibility and radial rigidity, which are essential for navigating tortuous and stenotic vessels while avoiding obstruction by vessel walls or previously deployed stents, as they require contradictory material properties for deliverability.
Innovation Solution
A catheter tip with a spring element that provides both longitudinal flexibility and radial rigidity, featuring a tapered shape and tightly packed coils, which minimizes the risk of catching or buckling by maintaining pushability and radial support, and is designed to be radially rigid at the distal end to prevent flaring and kinking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the catheter tip is made with longitudinal flexibility to accommodate tortuous vessels, then deliverability through curved vessels is improved, but pushability and radial rigidity deteriorate
Solution Approach 1:
The catheter tip incorporates a spring element with specific coil geometry that provides radial rigidity at the distal tip while maintaining longitudinal flexibility. The spring's coil structure allows bending along the catheter axis while resisting radial compression, creating localized differential mechanical properties that resolve the contradiction between flexibility and rigidity requirements.
Solution Approach 2:
The catheter tip combines the spring element (providing radial support and flexibility) with a radiopaque coating or material (enhancing visibility). This composite structure integrates multiple functional properties - mechanical flexibility, radial rigidity, and radiopacity - into a single tip assembly, simultaneously addressing deliverability, pushability, and imaging requirements.
2Strength
If the catheter tip is made with radial rigidity to prevent collapse and kinking, then pushability is improved, but longitudinal flexibility deteriorates
Solution Approach 1:
The spring element is positioned specifically at the distal tip where radial rigidity is most needed to prevent collapse during pushing. The coiled structure geometry provides radial support while inherently allowing longitudinal bending, creating localized differential mechanical properties that resolve the contradiction between flexibility and rigidity requirements.
Solution Approach 2:
The spring's helical/coiled geometry inherently provides curvature and flexibility along the catheter axis while maintaining radial rigidity. The curved coil structure allows the tip to bend and conform to vessel curvature while the spring mechanics resist radial compression and collapse, simultaneously achieving both flexibility and rigidity.
3Ease of operation
If the catheter tip shape is modified to avoid catching on vessel surfaces, then deliverability is improved, but the risk of obstruction by stents or lesions increases
Solution Approach 1:
The spring element acts as a cushioning element at the catheter tip, absorbing and distributing contact forces when the tip encounters vessel walls, lesions, or stents. This pre-positioned compliant structure prevents the tip from catching or obstructing by providing gradual deformation and force distribution, reducing the risk of obstruction while maintaining smooth deliverability.
Solution Approach 2:
The spring element provides dynamic response to contact forces during catheter advancement. When the tip encounters resistance from vessel walls or stents, the spring compresses and adjusts the contact force dynamically, allowing the catheter to navigate obstacles without catching or obstructing. This dynamic mechanical response improves both deliverability and reliability.
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
Enhances deliverability through tortuous and stenotic vessels with minimal risk of obstruction or deformation, allowing for precise navigation and reduced risk of damage to vessel walls, while maintaining pushability and radial support.
Implementation Method 1
a spring element (30) that provides longitudinal flexibility and radial rigidity
Data Source
Figure 1~1A
Figure 2~2A
Figure 3~4
AI summary
A catheter tip (20, 120) having a spring element (30, 130, 230, 330) that imparts longitudinal flexibility, pushability and radial rigidity to the catheter tip, thereby improving deliverability, is provided. The spring element also provides radial support to the distal edge of the catheter tip. The spring element may taper distally, but may have a substantially constant inner luminal diameter. The spring element may be partially covered or embedded, leaving its distal end exposed. The spring element may also include spaced coils in a proximal region. The apparatus may be used with any interventional catheter system, but is particularly suitable for use with balloon-expandable stent systems and balloon-angioplasty systems, where flexibility of the catheter tip and minimal flaring of the distal edge of the catheter tip is desirable.