Expandable Vascular Introducer Sheath Dynamics
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Solution Overview
Problem
Existing vascular access devices require multiple sheath sizes to accommodate large therapeutic devices, leading to increased trauma, bleeding, and infection risk due to repeated introductions and removals, and existing expandable sheaths have limitations in friction resistance and construction complexity.
Innovation Solution
A vascular introducer with a dynamically expandable sheath that transitions inner diameters in response to different-sized dilators, featuring lubricious material and rib designs to reduce friction and improve strength, allowing for easier passage of devices without needing removal from the surgical access point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple intermediate sheath sizes are successively introduced and removed to reach the largest introducer size required, then the ability to accommodate large therapeutic devices is improved, but vessel damage, bleeding, and infection risk increase due to repeated introductions and removals
Solution Approach 1:
The sheath is designed with dynamic expandability, transitioning from a compressed low-profile configuration for initial access to an expanded configuration that accommodates large therapeutic devices. The sheath includes expandable structures such as balloons or self-expanding frames that can be deployed within the vessel to increase the effective inner diameter without requiring removal and replacement with larger sheaths, thereby eliminating repeated puncture trauma
Solution Approach 2:
The sheath is designed to accommodate multiple dilators of different sizes within its structure. Smaller dilators can be nested within the sheath during the procedure, allowing sequential upsizing of the access pathway while maintaining a single continuous sheath in place, thus avoiding the need to remove and re-introduce multiple sheaths
2Object-affected harmful factors
If a smaller sheath size is used during percutaneous procedure to reduce trauma, then access site trauma is reduced, but the ability to deliver large therapeutic devices is limited
Solution Approach 1:
The sheath maintains a small compressed profile for initial percutaneous insertion to minimize trauma, then dynamically expands within the vessel to provide a large bore for delivering therapeutic devices. This dynamic size transformation allows the sheath to satisfy both the minimal access requirement and the large device delivery requirement
Solution Approach 2:
The sheath's inner diameter parameter is changed from a small initial value to a large final value through controlled expansion mechanisms. This parameter transformation enables the sheath to adapt its size according to the procedural needs at different stages, starting small for access and becoming large for device delivery
3Reliability
If existing expandable sheaths are used to avoid removal from operative site, then the need for multiple sheath introductions is reduced, but friction resistance and construction complexity remain limitations
Solution Approach 1:
The sheath incorporates flexible membrane structures that can expand and contract while maintaining structural integrity. These thin-film expandable sections provide the necessary compliance and size transformation capability with relatively simple construction, avoiding complex mechanical assemblies
Solution Approach 2:
The sheath utilizes composite material construction combining materials with different mechanical properties to achieve both expandability and structural strength. This composite approach allows the sheath to be complex in function but relatively simple in construction, using material properties rather than mechanical complexity to achieve the desired behavior
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 introducer reduces frictional resistance and insertion force, enabling seamless expansion to accommodate larger devices while minimizing trauma and simplifying manufacturing, thus enhancing procedural safety and efficiency.
Implementation Method 1
The central lumen of the tubular sheath includes a lubricious material to allow for easier passage of dilators and devices, for instance, due to decreased frictional resistance and insertion force during passage of a device within the vascular introducer
Implementation Method 2
The tubular sheath is formed from an expandable polymeric material. The central lumen of the tubular sheath includes an unexpanded configuration and an expanded configuration
Implementation Method 3
The tubular sheath includes a plurality of circumferentially spaced apart elongated struts disposed partially within the sheath wall, such that an exposed portion of each of the plurality of struts extends radially inwardly from an inner surface of the sheath wall into the central lumen
Data Source
AI summary
In various examples, a vascular introducer is described. The vascular introducer includes a proximal housing defining an axial passageway. An elongated tubular sheath extends distally from the proximal housing and includes a sheath wall defining a central lumen. The central lumen of the tubular sheath includes an unexpanded configuration and an expanded configuration. The central lumen in the unexpanded configuration includes a first inner diameter, and the central lumen in the expanded configuration includes a second inner diameter, the second inner diameter being larger than the first inner diameter. The tubular sheath includes a plurality of circumferentially spaced apart elongated struts disposed partially within the sheath wall, such that an exposed portion of each of the plurality of struts extends radially inwardly from an inner surface of the sheath wall into the central lumen.