Expandable Introducer Sheath for Smaller Vessel Openings
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing introducer sheaths for medical devices, such as intracardiac heart pumps, are not radially expandable, leading to issues like excessive vessel opening, tearing, bleeding, and vascular complications due to the need for a larger diameter sheath, and risk of clot formation over extended use.
Innovation Solution
An expandable introducer sheath with a frame and coating configuration that allows for a smaller initial size, minimizes friction, and maintains position, reducing the need for multiple sheaths and minimizing vessel trauma, while being compatible with a dilator assembly for controlled expansion and contraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a non-expandable introducer sheath is used, then the sheath can maintain structural integrity and provide stable access, but the inner diameter must be large enough to accommodate the largest device portion, leading to excessive vessel opening and increased risk of bleeding and vascular complications
Solution Approach 1:
The introducer sheath transitions from a static non-expandable structure to a dynamic expandable structure that can change its inner diameter. The sheath expands to a first inner diameter during device insertion to accommodate the pump assembly, then contracts to a second smaller inner diameter for prolonged positioning, thereby adapting to different operational requirements and minimizing vessel trauma.
Solution Approach 2:
The sheath's inner diameter parameter is changed dynamically - expanding to a larger first inner diameter when the medical device needs to pass through, then contracting to a smaller second inner diameter for stable positioning. This parameter change allows the sheath to accommodate large devices while minimizing the vessel opening size during the positioning phase.
2Ease of operation
If a peel away introducer sheath is used, then the sheath can be removed after device insertion, but the sheath may tear too easily or require excessive force, leading to bleeding, vascular complications, or inadvertent shifting of the pump position
Solution Approach 1:
Instead of a static peel-away design that requires catastrophic failure to remove, the sheath uses a dynamic expandable/contracting mechanism. The sheath is contracted to facilitate device passage, then expanded to lock in position with enhanced stability. Removal is achieved through controlled contraction rather than forceful tearing, eliminating the risk of premature tearing or excessive force application.
Solution Approach 2:
The sheath design anticipates potential removal issues by incorporating an expandable structure that provides mechanical interlocking with the delivery system. This preemptive design feature prevents premature tearing by distributing stresses evenly, and prevents excessive force requirements by using the expansion mechanism to secure the sheath in place before device passage is complete.
3Adaptability or versatility
If a completely flexible expandable sheath is used, then the sheath can expand to allow device passage, but the sheath lacks rigidity, leading to kinking or buckling during insertion or withdrawal of the percutaneous medical device
Solution Approach 1:
The sheath employs a composite construction combining flexible expandable material with embedded rigid support elements. This composite structure allows the sheath to expand radially to accommodate devices while the rigid components prevent axial kinking and buckling, providing both adaptability and structural strength simultaneously.
Solution Approach 2:
The sheath is divided into functional segments - an expandable outer layer that provides adaptability for device passage, and an inner rigid support structure that maintains structural integrity. This segmentation allows each component to perform its specialized function without compromising the other.
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 vascular complications, minimizes bleeding, and maintains access to the vessel for extended periods, enhancing procedural efficiency and reducing costs by eliminating the need for multiple sheaths and simplifying the insertion process.
Implementation Method 1
an expandable sheath frame (220) having a length, an exterior surface, an interior surface that forms an interior lumen along the length of the frame, and a contracted state and an expanded state
Implementation Method 2
The frame has a smooth coating about the exterior surface
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
An introducer sheath (200) for the insertion of a medical device into a blood vessel having an expandable sheath. The sheath has a length, a thickness, and proximal and distal ends. The expandable sheath has a frame extending longitudinally between the proximal end and the distal end, and having an exterior surface and an interior surface that forms an interior lumen along the length of the frame. The frame is configured to achieve an expanded state and a contracted state, the expanded state forming an expanded cross-section in the lumen for passing a medical device therethrough. The frame has a smooth coating about the exterior surface and protrusions extending into the lumen along the interior surface.