Elastomeric Friction Pad with Modulating Elements for Resheathing
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Solution Overview
Problem
Existing intravascular implant delivery systems face challenges in accurately positioning implants due to radial outward bulging of friction pads, which increases track/resheath force and potential for particle generation, while maintaining desired radial compressibility and lateral flexibility.
Innovation Solution
A pusher member assembly with a friction pad comprising an elastomeric base material and modulating elements, such as solid beams or gels, is used to enhance columnar strength and reduce radial strength, allowing for controlled deployment and resheathing of intravascular implants without excessive force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a friction pad is used to engage the intravascular implant for deployment, then the implant can be pushed forward for positioning, but the friction pad radially outward bulges increasing track/resheath force and particle generation
Solution Approach 1:
The friction pad material parameters are changed by incorporating particles with specific properties (durometer 40-70A,粒径5-50 micrometers) into the elastomeric matrix. This modifies the friction coefficient and radial compliance of the pad, allowing it to engage the implant for deployment while reducing radial outward bulging that causes particle generation and excessive track force
Solution Approach 2:
The friction pad is constructed as a composite material consisting of an elastomeric base material (such as polyurethane or silicone) combined with dispersed particles (such as polyethylene, polytetrafluoroethylene, or glass particles). This composite structure provides both the friction necessary for implant engagement and the radial compliance to minimize bulging and particle generation
2Force
If the friction pad is made more compliant to reduce track force, then resheathing becomes easier, but the implant may slip during deployment
Solution Approach 1:
The composite friction pad material provides optimized force characteristics through the combination of elastomeric matrix and dispersed particles. The elastomeric base provides compliance for easy resheathing, while the particle reinforcement maintains friction engagement stability, preventing implant slip during deployment
Solution Approach 2:
The friction pad's mechanical parameters are tuned by controlling particle concentration (10-50 wt%), particle size (5-50 micrometers), and particle hardness (durometer 40-70A). These parameter adjustments create an optimal balance between radial compliance for low track force and axial friction for reliable implant engagement
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
The solution minimizes radial outward bulging, facilitating precise implant positioning and reducing particle generation, while maintaining flexibility and enabling safe deployment and resheathing of intravascular implants.
Implementation Method 1
The friction pad is configured for frictionally engaging the intravascular implant as the pusher member assembly and the delivery catheter are axially translated relative to one another
Implementation Method 2
The friction pad comprises a tubular pad body having an elastomeric base material and at least one modulating element embedded within and axially extending along the elastomeric base material
Data Source
Figure 1~2
Figure 3A~3B
Figure 4A~4B
AI summary
An intravascular implant delivery system comprises an intravascular implant having a tubular implant body and a central implant lumen. The system further comprises a delivery catheter having an elongate sheath body and an inner sheath lumen. The intravascular implant is disposed within the inner sheath lumen when in a compressed delivery configuration. The system further comprises a pusher member assembly slidably disposed in the inner sheath lumen. The pusher member assembly comprises an elongate pusher member and a friction pad having a radially compressed state and a radially expanded state. The friction pad is disposed within the central implant lumen when in the radially compressed state. The friction pad comprises a tubular pad body and a central pad lumen in which the pusher member is disposed. The tubular pad body has an elastomeric base material and modulating elements embedded within and axially extending along the elastomeric base material.