Expandable Introducer Sheath for Smaller Vessel Access
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Solution Overview
Problem
Existing introducer sheaths for medical devices, particularly for intracardiac blood pumps, are not radially expandable, leading to issues such as excessive vessel opening, tearing, and vascular complications, and require multiple sheaths for insertion and removal, complicating procedures and increasing the risk of bleeding and clot formation.
Innovation Solution
An expandable introducer sheath with a frame and coating configuration that allows for a smaller size insertion and minimizes vessel trauma, reducing the need for multiple sheaths by expanding and contracting to accommodate the device, while maintaining vessel access and minimizing friction and clot formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a non-expandable introducer sheath is used, then the sheath can be inserted into the femoral artery, but the inner diameter must be large enough to accommodate the largest diameter portion of the pump assembly, creating an opening wider than necessary
Solution Approach 1:
The introducer sheath is designed with expandable and collapsible characteristics, allowing it to dynamically change its inner diameter. The sheath expands to a larger diameter during device insertion to accommodate the pump assembly, then collapses to a smaller diameter afterward to minimize vessel opening size, thereby resolving the contradiction between accommodating large devices and minimizing vascular trauma
Solution Approach 2:
The sheath's inner diameter parameter is changed from a fixed value to a variable value that can be adjusted between expanded and collapsed states. This parameter change allows the sheath to optimize its dimensions for different operational phases: larger during insertion and smaller during recovery, eliminating the need to maintain a permanently large opening
2Ease of operation
If a peel away introducer sheath is used, then the sheath can be removed after insertion, but it can tear too easily or require excessive force, leading to bleeding or vascular complications
Solution Approach 1:
The sheath transitions from a static, peel-away design to a dynamic, controlled removal system. The collapsible sheath can be gradually compressed and withdrawn under controlled conditions, allowing the operator to manage the removal process smoothly without sudden tearing or excessive force application, thereby improving both ease of operation and vascular safety
Solution Approach 2:
The sheath design incorporates gradual collapse capability that cushions the removal process. By allowing controlled compression and gradual withdrawal, the system prevents sudden mechanical failures or traumatic tearing that could cause bleeding or vascular complications
3Ease of operation
If a peel away introducer sheath is used, then the sheath can be removed, but it leads to a larger vessel opening after removal, complicating vessel closure
Solution Approach 1:
The sheath's diameter parameter is dynamically changed from a permanently large opening to a minimally invasive closing state. After device delivery, the sheath collapses to its smaller diameter, allowing the vessel opening to naturally reduce in size and facilitating simpler closure procedures
4Object-affected harmful factors
If an expandable introducer sheath is used, then a smaller size sheath can be used for insertion, but the sheath must expand to accommodate the device being introduced
Solution Approach 1:
The sheath incorporates expandable structural elements that allow it to transition from a compact insertion state to an expanded delivery state. This dynamic capability enables the use of a smaller sheath for insertion (reducing vessel trauma) while still accommodating larger devices during the procedure
Solution Approach 2:
The sheath structure is segmented into expandable sections that can be deployed as needed. This segmentation allows the sheath to maintain a small profile during insertion while expanding locally or globally to accommodate the medical device, resolving the contradiction between minimal invasion and device accommodation
5Duration of action of moving object
If a completely flexible expandable sheath is used, then the sheath can expand and contract, but it does not provide rigidity, leading to kinking or buckling during insertion or withdrawal
Solution Approach 1:
The sheath is constructed as a composite structure combining flexible materials with rigid or semi-rigid support elements. This composite design provides the necessary rigidity to prevent kinking and buckling during insertion and withdrawal while maintaining the expandability and contractility needed for minimal invasion and device accommodation
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 simplifies insertion procedures, reduces bleeding and vascular complications, and maintains vessel access, providing a more efficient and safer method for delivering medical devices by minimizing friction and clotting risks.
Implementation Method 1
A coating is applied to the surface of the sheath to facilitate passage inside the patient
Implementation Method 2
The frame is configured to achieve an expanded state and a contracted state
Implementation Method 3
protrusions extending into the lumen along the interior surface of the frame
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
An introducer sheath 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 and the distal ends, 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. The introducer sheath can be introduced into a patient in the contracted state, with the distal end of the introducer sheath prevented from moving in the proximal direction by an abutment against a dilator end surface.