Tri-Layer Sheath Catheter for Low-Profile Kink Resistance
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Solution Overview
Problem
Existing sheath catheters for stent deployment face challenges in balancing flexibility, kink resistance, axial tensile and compressive strength, and minimizing exterior diameter while maintaining interior diameter, which affects the efficiency and precision of stent deployment in vascular procedures.
Innovation Solution
A tri-layer sheath catheter design featuring a lubricious PTFE inner polymer liner, braided reinforcement skeleton tube, and durable outer jacket, with a distal radiopaque marker band for enhanced visualization, providing low-profile, flexible, and trackable performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the sheath catheter uses a thicker wall construction to improve strength and kink resistance, then axial tensile and compressive strength improve, but the exterior diameter increases and flexibility decreases
Solution Approach 1:
The sheath catheter employs a composite construction combining a braided reinforcement layer (providing strength and kink resistance) with an inner polymer liner (providing flexibility and lubricious surface). This composite structure allows the catheter to achieve both mechanical strength and flexibility simultaneously, resolving the contradiction between strength and ease of operation.
Solution Approach 2:
The sheath catheter is divided into distinct functional layers: a braided reinforcement skeleton tube for structural strength and kink resistance, and a separate inner polymer liner for flexibility and low-friction passage. This segmentation allows each layer to optimize its specific function without compromising the other, enabling the catheter to navigate tortuous vessels while maintaining structural integrity.
2Stability of the object's composition
If the sheath catheter uses a thicker wall construction to improve kink resistance, then kink resistance improves, but the interior diameter decreases
Solution Approach 1:
The braided reinforcement layer provides kink resistance through its woven structure, while the inner polymer liner maintains a smooth, lubricious interior surface that preserves adequate interior diameter for device passage. The composite construction allows the catheter to resist kinking without requiring excessive wall thickness that would reduce the interior lumen.
Solution Approach 2:
The braided reinforcement is strategically positioned in the wall construction to provide kink resistance where needed, while the inner polymer liner provides a low-friction surface that facilitates device passage. This localized functional assignment allows the catheter to achieve kink resistance without uniformly increasing wall thickness throughout, thereby preserving interior diameter.
3Shape
If the sheath catheter minimizes exterior diameter for low-profile access, then ease of insertion improves, but strength and kink resistance decrease
Solution Approach 1:
The sheath catheter uses a composite structure where a thin-walled construction provides low-profile access, while an integrated braided reinforcement layer compensates for the reduced wall thickness by providing the necessary axial tensile strength and kink resistance. This allows the catheter to maintain a small exterior diameter without sacrificing mechanical strength.
Solution Approach 2:
The catheter wall is segmented into functional components: a thin outer structure for low-profile access, and an embedded braided reinforcement skeleton for strength. This segmentation allows the catheter to achieve minimal exterior diameter while the reinforcement layer provides the necessary mechanical properties that would otherwise require thicker walls.
4Ease of operation
If the sheath catheter uses a lubricious inner surface to reduce friction during passage, then ease of operation improves, but manufacturing complexity increases
Solution Approach 1:
The sheath catheter integrates a lubricious inner polymer liner as part of the composite wall structure. This liner provides a low-friction surface that facilitates smooth passage through vessels and ease of device deployment, while being manufactured as an integrated component of the catheter assembly, thereby managing manufacturing complexity through consolidation rather than adding separate assembly steps.
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
Enables precise and controlled stent delivery in small, tortuous vessels with improved procedural efficiency and patient outcomes by ensuring superior flexibility, kink resistance, and structural integrity.
Implementation Method 1
a lubricious polytetrafluoroethylene (PTFE) inner polymer liner to minimize friction during device passage
Implementation Method 2
a braided reinforcement skeleton tube for superior tensile strength and kink resistance
Data Source
AI summary
A novel sheath catheter is designed for broad applicability in intravascular percutaneous procedures, featuring a proximal hub, an elongate shaft, and a distal radiopaque marker band for enhanced visualization. The elongate shaft incorporates a tri-layer construction: a lubricious polytetrafluoroethylene (PTFE) inner polymer liner to minimize friction during device passage, a braided reinforcement skeleton for superior tensile strength and kink resistance, and a durable, wear-resistant outer jacket to withstand navigational stresses. This configuration yields a low-profile design with exceptional pushability, flexibility, and trackability, enabling access to small, tortuous vessels while maintaining structural integrity.