Expandable Railed Sheath for Vessel Protection
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Solution Overview
Problem
Conventional percutaneous valve replacement procedures face challenges due to the need for large instrumentation that can cause damage to diseased major vessels, leading to elevated stroke rates from emboli formation during insertion through atherosclerotic vessels.
Innovation Solution
An expandable railed sheath with a porous wall and radioopaque markers is introduced, which can be guided through diseased vessels to protect the vessel walls from instrumentation and filter out emboli, allowing for minimally invasive procedures while preventing emboli passage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If large instrumentation is used for percutaneous valve replacement, then the valve can be successfully deployed, but the diseased vessel walls are damaged and emboli are formed
Solution Approach 1:
A thin-walled protective sheath is introduced as an intermediary component between the large valve instrumentation and the diseased vessel walls. The sheath has a collapsed configuration for insertion through the vessel and an expanded configuration that provides a protective barrier during valve deployment, preventing direct contact and damage to the vessel wall while allowing successful valve placement.
Solution Approach 2:
The protective sheath transitions from a collapsed low-profile configuration during insertion to an expanded high-profile configuration during valve deployment. This dynamic transformation allows the sheath to minimize insertion profile while providing maximum protection during the critical valve placement procedure, resolving the contradiction between device size and vessel protection.
2Object-affected harmful factors
If a protective sheath is inserted to protect vessel walls, then vessel damage is reduced, but the sheath itself may become a source of emboli
Solution Approach 1:
The protective sheath incorporates a porous filter structure that allows blood flow through the wall while physically blocking emboli and debris from passing through. This porous design enables the sheath to protect against vessel wall damage while simultaneously filtering harmful particles, converting the sheath from a potential emboli source to an emboli filter.
Solution Approach 2:
The sheath wall is designed with non-uniform properties, being porous in regions where filtration is needed and potentially denser in other regions. This local variation in material quality allows the sheath to provide protection while enabling controlled permeability for blood flow and emboli filtration, addressing the contradiction between protection and emboli generation.
3Length of moving object
If the sheath is made thin to reduce profile, then insertion is easier, but structural strength is reduced
Solution Approach 1:
The sheath employs dynamic structural transformation, transitioning from a thin-walled collapsed state during insertion to a thick-walled expanded state during deployment. This dynamic change allows the sheath to achieve a low insertion profile while providing sufficient structural strength when expanded, resolving the contradiction between thin profile and structural strength.
Solution Approach 2:
The thin-walled sheath is nested within a delivery system that provides additional structural support during insertion. The delivery system acts as an outer protective layer, allowing the thin-walled sheath to be inserted without compromising strength, and then the sheath is deployed outward after insertion, enabling both thin profile and adequate strength.
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 the risk of emboli formation and vessel damage by providing a protective layer and filtering mechanism, facilitating safer and more effective percutaneous valve replacements.
Implementation Method 1
The porous wall may be configured to filter blood flowing through it to prevent passage of emboli that may be present within the lumen
Implementation Method 2
one or more radioopaque markers coupled to the sheath and configured to assist an operator observing fluoroscopy with positioning of the sheath relative to the diseased vessel
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
Configurations are described for assisting execution of a percutaneous procedure while protecting the vascular pathway to the operational theater. One embodiment is directed to a system for deploying a device to a distal location across a diseased vessel, comprising a sheath comprising an expandable distal portion comprising a porous wall defining a lumen therethrough, the distal portion having a collapsed configuration, wherein the sheath has a first cross sectional outer diameter and a first lumen inner diameter, and an expanded configuration, wherein the sheath has a second cross sectional outer diameter and a second lumen inner diameter; wherein in the collapsed configuration, the sheath is configured to be advanced across at least a portion of the diseased vessel to a position adjacent the distal location without substantial size interference between the first cross sectional outer diameter of the sheath and an inner diameter profile of a lumen of the vessel.