Catheter Torque Transfer Layer Using Braided Flat Wires
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Solution Overview
Problem
Existing introducer catheters face challenges in balancing pushability, torqueability, flexibility, and kink resistance, often requiring compromises that affect their performance in navigating the human vasculature, particularly in cardiac procedures where a large bore size is necessary.
Innovation Solution
A catheter design featuring a tubular inner liner with a torque transfer layer composed of braided flat wires and an outer sheath made of melt-processing polymer, allowing for improved pushability, torqueability, and kink resistance while maintaining a large bore size, achieved through a manufacturing process involving a reflow bonding method.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the bore size of an introducer catheter is increased to accommodate larger devices, then the inner diameter increases, but the wall thickness must be reduced which compromises torqueability and kink resistance
Solution Approach 1:
The catheter employs a composite construction with a braided torque transfer layer made of flat wires embedded within a flexible polymer matrix. This composite structure allows the catheter to maintain large bore size while the braided layer provides the necessary torque strength and kink resistance that would otherwise require thicker walls.
Solution Approach 2:
The torque transfer properties are localized to specific regions through the braided layer configuration. The flat wire braid is positioned strategically to provide torqueability where needed while maintaining overall flexibility and large bore dimensions in other areas of the catheter.
2Strength
If reinforcing layers are added to improve torqueability and kink resistance, then strength increases, but the overall diameter increases for a given bore size
Solution Approach 1:
The catheter uses a thin-walled flexible polymer casing that provides the necessary structural support without significantly increasing the overall diameter. The flexible shell works in conjunction with the braided torque transfer layer to maintain strength while keeping the catheter profile suitable for vascular navigation.
Solution Approach 2:
The composite structure of the braided flat wire layer within the flexible polymer matrix provides high torque strength in a compact configuration, avoiding the need for thick reinforcing walls that would increase the overall diameter.
3Area of stationary object
If the wall thickness is reduced to maintain a small overall diameter, then the overall diameter decreases, but pushability and resistance to collapse under torque are compromised
Solution Approach 1:
The braided flat wire torque transfer layer embedded in the flexible polymer matrix creates a composite structure that provides exceptional pushability and collapse resistance despite thin walls. The braided configuration efficiently transmits axial forces while the flexible polymer provides structural integrity.
Solution Approach 2:
The flat wire braid configuration with its curved, interwoven structure provides mechanical strength and force transmission capabilities that are disproportionate to the thin wall thickness, enabling small overall diameter while maintaining pushability.
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 design enables introducer catheters with enhanced axial strength, directional control, and resistance to kinking, facilitating effective navigation of the vasculature during cardiac procedures without compromising on pushability, torqueability, or flexibility.
Implementation Method 1
an outer sheath made of melt-processing polymer, allowing for improved pushability, torqueability, and kink resistance while maintaining a large bore size, achieved through a manufacturing process involving a reflow bonding method
Data Source
AI summary
The instant invention relates generally to catheters and to introducer catheters used to help deliver catheters or other medical devices to locations within the human body. In particular, the instant invention relates to large diameter catheters and introducer catheters having a torque transfer layer that includes at least two flat wires braided into a wire mesh. The flat wires have a width of at least about 0.007 inches and a depth of at least about 0.003 inches. The lumen diameter of the catheter is at least about 6 French. The torque transfer layer provides increased strength, flexibility, and kink resistance.