Stretched PTFE Liner Microcatheter for Low Friction Delivery
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Solution Overview
Problem
Existing microcatheters used for delivering expandable vascular reconstruction devices, such as flow diversion tubes and embolization devices, face challenges with high friction and liner damage during device delivery, leading to complications like skiving of catheter material into the vasculature.
Innovation Solution
The microcatheter is enhanced with a stretched PTFE liner that has a low coefficient of friction and increased toughness, combined with a layered construction including a coil and a sheath, to reduce friction and resistance during device delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a conventional PTFE liner is used in the microcatheter, then the microcatheter can deliver expandable devices, but high friction occurs between the device and liner causing delivery difficulties and liner damage
Solution Approach 1:
The patent modifies the PTFE liner by stretching it longitudinally to change its physical parameters, resulting in a stretched PTFE liner with improved mechanical properties including reduced friction coefficient and increased toughness, thereby resolving the contradiction between low friction and high reliability
Solution Approach 2:
The patent creates a composite structure by combining the stretched PTFE liner with additional layers (such as a coil and sheath) to form a layered construction that maintains liner integrity while reducing friction during device delivery
2Ease of operation
If expandable devices are compressed for delivery through the microcatheter, then the devices can be delivered through the catheter, but the compressed shape exerts outward radial force causing friction and making delivery difficult
Solution Approach 1:
The stretched PTFE liner has modified physical parameters that reduce the coefficient of friction, allowing compressed devices to be delivered more easily through the microcatheter with reduced radial friction forces
3Device complexity
If the microcatheter liner is made thinner to reduce profile, then the catheter is more flexible and easier to navigate, but the liner becomes more susceptible to scraping and damage
Solution Approach 1:
The stretching process modifies the physical parameters of the PTFE liner, increasing its toughness and resistance to scraping while maintaining a thin profile, thereby resolving the contradiction between low profile and high strength
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 improved microcatheter design reduces delivery friction by 15-30% and decreases the risk of liner material deposition, facilitating easier navigation of devices through tortuous vascular paths with reduced force requirements and enhanced durability.
Implementation Method 1
The PTFE liner (or a portion of the liner) is only stretched longitudinally and not circumferentially or radially over at least a portion of the length of the microcatheter. The enhanced liner results in a reduction of the delivery friction
Data Source
AI summary
A microcatheter with an enhanced inner liner that has low of friction and improved toughness which facilitates delivery of expandable vascular reconstruction devices.