Expandable Introducer Sheath for Large-Device Delivery Access
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Solution Overview
Problem
Existing introducer devices for transcatheter delivery systems often require large sheaths, leading to increased complications and trauma due to their size, which is undesirable for minimally invasive procedures.
Innovation Solution
An expandable introducer sheath with a mesh tube, a thin, flexible liner, and an axial strip that allows the sheath to expand from a small diameter for insertion to a larger diameter for device delivery, featuring a foldable liner and a braided mesh material for reduced snagging and improved hemostatic sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a large sheath is used to accommodate large delivery devices, then the delivery device can be introduced, but the insertion profile increases leading to more complications and trauma
Solution Approach 1:
The introducer sheath transitions from a compressed low-profile state during insertion to an expanded high-lumen state during device delivery. The sheath includes expandable structures such as balloons or self-expanding frames that allow dynamic change in lumen diameter, enabling small insertion profile followed by large delivery capability without requiring a permanently large sheath
Solution Approach 2:
The delivery device is nested within the expandable sheath structure, allowing the device to pass through the introducer in a compact configuration. The sheath expands to provide adequate clearance around the device during delivery while maintaining a small overall profile during insertion, effectively nesting the delivery system within the introducer
2Object-affected harmful factors
If a small sheath is used for minimally invasive access, then vascular trauma is reduced, but large delivery devices cannot be accommodated
Solution Approach 1:
The introducer sheath maintains a small diameter during insertion to minimize vascular trauma, then dynamically expands to a large diameter to accommodate delivery devices. This dynamic transformation is achieved through expandable balloon elements or self-expanding frame structures that increase the lumen diameter only when needed for device delivery
Solution Approach 2:
The sheath structure changes its physical parameters (diameter, cross-sectional area) from a small compressed state to a large expanded state. Material properties and structural configurations are designed to allow this parameter change, transitioning from a narrow profile suitable for percutaneous access to a wide lumen capable of accommodating large delivery devices
3Adaptability or versatility
If the sheath is made expandable to accommodate both small and large devices, then versatility is improved, but device complexity increases
Solution Approach 1:
The sheath is divided into functional segments including a proximal hub, a mid-portion with expandable structures, and a distal tip. The expandable portion is segmented into radial elements or circumferential balloons that can expand independently, allowing controlled enlargement of the lumen while keeping the overall structure manageable and modular
Solution Approach 2:
The sheath incorporates flexible expandable structures such as balloon elements or thin-walled self-expanding frames made from compliant materials. These flexible components allow the sheath to transition between compressed and expanded states without requiring complex mechanical mechanisms, reducing overall device complexity while maintaining versatility
Data Source
Figure 1
Figure 2A~2D
Figure 3A~3B
AI summary
An expandable introducer device includes an introducer hub and an introducer sheath coupled to the hub and extending distally therefrom. The introducer sheath includes a mesh tube, a liner disposed within the mesh tube, and an axial strip disposed between the mesh tube and the liner. The introducer sheath is radially-expandable from a first diameter to a second diameter larger than the first diameter in response to a device being advanced through the introducer sheath.