Expandable Introducer Sheath for Low-Trauma Vessel Access
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Solution Overview
Problem
Conventional introducer sheaths for endovascular delivery systems require multiple vessel dilations, increasing procedure time and risk of vessel damage and plaque dislodgement, due to their large profile and complex mechanisms.
Innovation Solution
An expandable sheath with an inner and outer layer that temporarily expands to accommodate a delivery system, then returns to its original diameter, minimizing vessel trauma and reducing the need for multiple sheath sizes.
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 procedure time increases and the risk of vessel damage increases due to multiple dilations
Solution Approach 1:
The introducer sheath incorporates a radially expandable section that can dynamically change its diameter. The section is expandable from a compressed configuration (smaller diameter) to an expanded configuration (larger diameter), allowing the sheath to adapt its size during the procedure. This dynamic capability enables the sheath to be introduced in a compressed state and then expanded to accommodate the delivery system, eliminating the need for multiple sequential dilations and reducing procedure time while maintaining vessel safety.
2Strength
If conventional introducer sheaths with large profile are used, then the delivery system can be supported, but the risk of plaque dislodgement and vessel tearing increases
Solution Approach 1:
The introducer sheath is divided into distinct functional sections: a first section with a smaller diameter for initial vessel access, a radially expandable section for accommodating the delivery system, and a second section for distal support. This segmentation allows each section to perform its specific function optimally - the first section minimizes trauma during insertion, the expandable section provides necessary support, and the overall structure reduces the risk of plaque dislodgement compared to conventional single-diameter sheaths.
3Ease of operation
If conventional introducer sheaths require multiple dilators are used, then the delivery system can be introduced, but the complexity of the procedure increases
Solution Approach 1:
The radially expandable section incorporates an expansion mechanism that transitions the sheath from a compressed configuration to an expanded configuration. This dynamic mechanism integrates multiple functions into a single device - the ability to be introduced in a low-profile state and then expand to accommodate the delivery system, replacing the need for multiple separate dilators and reducing procedural complexity.
4Object-affected harmful factors
If a sheath with smaller profile is used, then vessel trauma is minimized, but the ability to accommodate the delivery system is reduced
Solution Approach 1:
The radially expandable section enables the sheath to transition between different diameter states. In the compressed configuration, the sheath has a smaller diameter that minimizes vessel trauma during insertion. When expanded, the same section provides a larger diameter that accommodates the delivery system. This dynamic adaptability resolves the contradiction by providing both small profile and large capacity at different stages of the procedure.
Solution Approach 2:
The sheath is segmented into a first section for initial access and a radially expandable section for accommodation. This segmentation allows the first section to maintain a smaller, trauma-minimizing profile while the expandable section can increase in diameter to accommodate the delivery system, providing both vessel safety and delivery capability.
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 expandable sheath reduces procedure time and minimizes vessel tears and plaque dislodgement by allowing single-vessel insertion and using materials like PTFE and HDPE for flexibility and strength.
Implementation Method 1
an expandable sheath with an inner and outer layer that temporarily expands to accommodate a delivery system, then returns to its original diameter
Data Source
AI summary
Embodiments of an expandable sheath can be used in conjunction with a catheter assembly to introduce a prosthetic device, such as a heart valve, into a patient. Such embodiments can minimize trauma to the vessel by allowing for temporary expansion of a portion of the introducer sheath to accommodate the delivery apparatus, followed by a return to the original diameter once the prosthetic device passes through. Some embodiments can include a sheath with inner and outer layers, where a folded portion of the inner layer extends through a slit in the outer layer and a portion of the outer layer overlaps the folded portion of the inner layer. Some embodiments include an elastic outer cover positioned outside the outer layer. Embodiments of the present expandable sheath can avoid the need for multiple insertions for the dilation of the vessel, thus offering advantages over prior art introducer sheaths.