Multi-Filar Catheter Body Cut Patterns for Flexibility and Axial Strength
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Solution Overview
Problem
Existing intravascular catheters face challenges in providing a combination of desirable pushability, fine torqueability response, axial strength stability, maintaining lumen concentricity, resistance to catheter body plastic deformation or fatigue, and variable flexibility, especially when navigating complex and tortuous vascular pathways.
Innovation Solution
A catheter design featuring multi-filar cut patterns with varying cut widths, pitch angles, and filar widths along its length, allowing for zones with controlled flexibility and stiffness, constructed from materials like nitinol, stainless steel, or polymers, to enhance steerability, torqueability, and kink resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a catheter is designed with small diameter to access tortuous vascular pathways, then flexibility and steerability are improved, but axial strength stability and resistance to plastic deformation deteriorate
Solution Approach 1:
The catheter body is segmented into multiple zones with different cut patterns, allowing each zone to have optimized flexibility characteristics while maintaining overall structural integrity and axial strength
Solution Approach 2:
The catheter employs a composite structure combining a cut patterned tube (nitinol, stainless steel, or inconel) with an inner polymer liner and outer polymer jacket, creating a multi-material system that balances flexibility and axial strength
2Adaptability or versatility
If a catheter is designed with high flexibility to navigate complex vasculature, then steerability is improved, but lumen concentricity and resistance to catheter body fatigue deteriorate
Solution Approach 1:
Different zones of the catheter body have locally optimized cut patterns with varying parameters (cut width, filar width, pitch angle, number of cuts) to provide specific flexibility characteristics in each zone while maintaining overall lumen concentricity and reliability
Solution Approach 2:
The cut pattern design allows the catheter to dynamically adjust its flexibility characteristics along its length, with the spaced cuts enabling controlled bending and steering while maintaining structural stability
3Adaptability or versatility
If a catheter is designed with variable flexibility along its length, then navigation through tortuous pathways is improved, but manufacturing complexity increases
Solution Approach 1:
The catheter body is divided into multiple zones with different cut patterns, allowing variable flexibility to be achieved through a single continuous tube rather than assembling multiple different components, thereby reducing manufacturing complexity
Solution Approach 2:
Variable flexibility is achieved by changing the parameters of the cut pattern (cut width, filar width, pitch angle, number of cuts) along the length of the catheter, allowing customization of flexibility characteristics without changing the basic catheter structure or material
Data Source
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AI summary
The invention refers to a catheter, comprising a catheter tube, which defines a proximal end; a distal end; a longitudinal axis; a lumen therethrough; and a first zone having a first cut pattern segment therein, wherein the first cut pattern segment defines a plurality of spiral cuts spaced around a circumference of the tube, wherein each of the plurality of spiral cuts defines a width between 0.015 mm and 0.040 mm, wherein each of the plurality of spiral cuts is spaced from an adjacent cut by a filar having a width between 0.015 mm and 0.125 mm, and wherein each of the plurality of spiral cuts defines a pitch angle with the longitudinal axis between 30 degrees and 70 degrees.