Expandable Sheath Tip Structure for Low-Trauma Device Delivery
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Solution Overview
Problem
Conventional introducer sheaths for delivering prosthetic devices require multiple vessel dilations, increasing procedure time and risk of vessel damage, and pose challenges due to their large profile, which can cause tearing and plaque dislodgement.
Innovation Solution
An expandable sheath with a tip section that temporarily expands to accommodate the delivery system, featuring an inner liner, intermediate layer, and elastomeric outer layer, allowing for single-vessel insertion and minimizing trauma by returning to the original diameter post-delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional introducer sheaths are used, then the delivery system can be introduced into the vasculature, but the sheath requires multiple vessel dilations which increases procedure time and risk of vessel damage
Solution Approach 1:
The sheath transitions from a compressed low-profile state during insertion to an expanded high-profile state during delivery system introduction, then returns to the compressed state for removal. This dynamic size change allows the sheath to accommodate large delivery systems without requiring multiple dilations, reducing both procedure time and vessel damage risk
Solution Approach 2:
The delivery system is nested within the expandable sheath in a telescoping arrangement. The sheath expands to receive the delivery system and then contracts to release it, allowing single-vessel access without multiple dilators or sheaths
2Strength
If conventional introducer sheaths with large profile are used, then the delivery system can be supported, but the large profile causes longitudinal and radial tearing of the vessel during insertion
Solution Approach 1:
The sheath maintains a small compressed profile during vessel insertion to avoid tearing, then expands to a large expanded profile to support the delivery system, and finally contracts to allow safe removal. This dynamic adaptation eliminates the need to choose between small insertion profile and large support profile
Solution Approach 2:
The sheath is divided into a proximal section and a distal tip section with different structural characteristics. The tip section is more compliant and expandable to reduce insertion trauma, while the proximal section provides structural support for the delivery system
3Ease of operation
If conventional introducer sheaths are used, then the delivery system can be introduced, but the sheath requires a tubular loader that decreases the available working length of the delivery apparatus
Solution Approach 1:
The expandable sheath eliminates the need for a permanent tubular loader by dynamically expanding at the target site to receive and support the delivery system. This allows the full length of the delivery apparatus to be utilized for working purposes rather than having a portion consumed by a fixed loader structure
4Reliability
If conventional methods with multiple dilators are used, then the vessel can be accessed, but repeated insertion and dilation increases the risk of plaque dislodgement and clots
Solution Approach 1:
The expandable sheath combines the functions of multiple dilators and the access sheath into a single device. By expanding within the vessel to create the access pathway, it eliminates the need for sequential dilation with multiple devices, reducing plaque dislodgement risk and procedural complexity
Solution Approach 2:
The sheath is pre-loaded in a compressed state and inserted through the vessel in a single action. It then expands to create the access pathway, performing the dilation function as a preliminary step before delivering the prosthetic device, rather than requiring multiple separate dilation 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
Reduces procedure time and minimizes vessel trauma by allowing single-vessel insertion and reducing the risk of tears and plaque dislodgement, while maintaining a smaller profile compared to conventional sheaths.
Implementation Method 1
an expandable sheath with a tip section that temporarily expands to accommodate the delivery system, featuring an inner liner, intermediate layer, and elastomeric outer layer, allowing for single-vessel insertion and minimizing trauma by returning to the original diameter post-delivery
Data Source
Figure 1
Figure 2A~2B
Figure 2C
AI summary
Various systems and devices are described herein pertaining to expandable sheaths (4400). Sheath aspects are described that include a flexible sheath tip that is expandable and bendable. The sheath includes a radially expandible proximal end and a radially expandable distal end. The sheath tip includes a plurality of layers (4408,4426,4410) that expand to accept a medical device traveling axially and bi-directionally therethrough with minimal deformation of the sheath tip, wherein an intermediate layer (4426) extends distally beyond an inner liner layer (4408) and an elastomeric outer layer (4410) to define a distal end of a tip section, wherein at least the inner liner layer defines a slit (4412) extending distally along at least a portion of the tip section.