Microcatheter with Segmented PTFE and Polyether Block Amide Layers
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Solution Overview
Problem
Microcatheters face challenges in navigating through narrow and tortuous blood vessels due to the need for a balance between stiffness for manipulation and flexibility to avoid trauma, with existing designs often compromising on strength, kinking resistance, and navigation through convoluted vessels.
Innovation Solution
A microcatheter design featuring an inner layer of Polytetrafluoroethylene (PTFE), a strike layer of polyether block amide, and an outer layer with varying durometer sections, including a distal portion made of polycarbonate-based thermoplastic polyurethane, combined with a metallic braid for exceptional strength, flexibility, and resistance to kinking, ensuring improved navigation through blood vessels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the microcatheter is made stiff at the proximal end to allow pushing and manipulation, then the ease of operation is improved, but the flexibility at the distal end deteriorates, making it difficult to pass through tortuous blood vessels
Solution Approach 1:
The microcatheter is divided into multiple sections with different stiffness characteristics. The proximal end has a stiffer construction for easy manipulation, while the distal end has a more flexible construction for navigating tortuous vessels. This segmentation allows each part to perform its specific function optimally without compromising the other.
Solution Approach 2:
Different sections of the microcatheter are assigned different material properties and structural characteristics. The proximal portion uses materials and constructions that provide stiffness for manipulation, while the distal portion uses materials and constructions that provide flexibility for navigation, creating local quality variations along the catheter length.
2Adaptability or versatility
If the microcatheter is made flexible at the distal end to pass through tortuous blood vessels, then the adaptability is improved, but the strength and resistance to kinking deteriorate
Solution Approach 1:
The microcatheter employs composite material construction, combining different materials with complementary properties. The distal end incorporates flexible materials for navigation while integrating reinforcement elements or structural features that prevent kinking, achieving both adaptability and strength through material composition.
Solution Approach 2:
The microcatheter structure is designed to be dynamic rather than static, allowing it to adapt its flexibility and strength characteristics in response to mechanical stresses. The distal end can flex to navigate vessels but recovers its shape through elastic properties, providing both adaptability and resistance to permanent deformation.
3Strength
If the microcatheter uses a thicker wall construction to improve strength, then the strength is improved, but the flexibility and ability to navigate narrow vessels deteriorates
Solution Approach 1:
The wall construction is segmented into different thicknesses and compositions along the catheter length. The proximal end may have thicker walls for strength during manipulation, while the distal end has thinner walls for flexibility, optimizing the strength-to-flexibility ratio in different operational zones.
Solution Approach 2:
The microcatheter utilizes thin-walled flexible shell construction, particularly at the distal end, where thin films or layered structures provide sufficient strength while maintaining high flexibility. This allows the catheter to navigate narrow and tortuous vessels without compromising structural integrity.
Data Source
AI summary
A microcatheter comprising an inner layer, a strike layer and an outer layer and a braided skeleton located between the inner layer and the outer layer, wherein the inner layer is made of Polytetrafluoroethylene (PTFE) and has a thickness of 0.0015 inch or less, wherein the strike layer includes a polyether block amide and has a thickness of 0.001 inch or less, and wherein a distal portion of said outer layer is made of polycarbonate-based thermoplastic polyurethane having a shore of 90A or below.