Combined Introducer and Expandable Sheath for Vascular Access
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Solution Overview
Problem
Current sheaths for delivering prosthetic devices, such as heart valves, into the patient's vasculature often require preliminary dilation steps, which can cause vessel damage and increase the risk of complications like clotting due to dislodged plaque.
Innovation Solution
A combined introducer and expandable sheath with a rounded and tapered distal tip, low inner diameter, and thick radially folded tapered segments, providing sufficient rigidity for insertion without the need for dilators and allowing for expansion to accommodate larger devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sheaths are used with preliminary dilation, then the sheath can be inserted into the vasculature, but the vessel is damaged and plaque is dislodged causing clots
Solution Approach 1:
The patent combines the introducer and sheath into a single integrated device. The introducer sheath includes an outer introducer portion and an inner sheath portion that work together as one unit, eliminating the need for separate dilation steps and reducing vessel trauma by avoiding multiple insertions and plaque dislodgement events.
Solution Approach 2:
The introducer sheath features variable wall thickness with thicker radially folded tapered segments that provide rigidity during insertion, then collapse to reduce profile. The device transitions from a rigid insertion configuration to a compliant delivery configuration, changing its mechanical parameters to suit different procedural phases while protecting the vessel.
2Ease of operation
If multiple tapered introducers are used for dilation, then the vessel can be accessed, but the procedure time increases and vessel damage risk increases
Solution Approach 1:
The introducer sheath integrates the dilation and sheath functions into a single device that can be inserted in one step. The radially folded tapered segments provide the necessary dilation capability while the integrated design eliminates the sequential insertion of multiple introducers, significantly reducing procedure time and maintaining ease of vessel access.
3Adaptability or versatility
If the sheath has a larger profile for device delivery, then larger prosthetic devices can be delivered, but the risk of longitudinal and radial tearing of the vessel increases
Solution Approach 1:
The introducer sheath employs dynamic wall structure with radially folded tapered segments that can change their radial profile. During insertion, the segments are compressed radially to reduce the sheath profile and minimize vessel contact pressure. Once positioned, the segments can expand to accommodate larger prosthetic devices, providing adaptability without causing vessel tearing.
Solution Approach 2:
The sheath features non-uniform wall thickness with thicker radially folded tapered segments strategically positioned to provide localized rigidity and support during insertion, while other portions remain more compliant. This localized variation in structural properties allows the sheath to deliver large devices without uniformly increasing the risk of vessel tearing along its entire length.
4Stability of the object's composition
If the sheath is made more rigid for insertion, then the sheath maintains its shape during insertion, but the sheath cannot be compressed for passage through narrow vessels
Solution Approach 1:
The introducer sheath uses radially folded tapered segments that can dynamically transition between expanded and compressed states. The segments maintain the sheath's structural integrity and shape stability during insertion, then can be compressed radially to reduce the profile for passage through narrow vascular segments, providing both rigidity and adaptability as needed.
Solution Approach 2:
The sheath is divided into multiple radially folded tapered segments rather than being a continuous rigid structure. This segmentation allows each segment to move independently, maintaining overall shape stability while enabling compression of individual segments to reduce the overall profile for passage through narrow vessels, then re-expand to support device delivery.
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 combined introducer and expandable sheath enables safe and efficient insertion and expansion within the vascular site without preliminary dilation, reducing the risk of vessel damage and procedural complications.
Implementation Method 1
an elongate outer elastomeric jacket extending at least partially over the inner member and having a spring bias toward the inner lumen of the inner member
Implementation Method 2
The plurality of radially folded tapered segments may unfold toward an inner surface of the outer elastomeric jacket to expand the inner diameter of the inner lumen upon insertion of a medical delivery device into the lumen
Data Source
AI summary
Disclosed herein is a combined introducer and expandable sheath having an inner member and an outer elastomeric jacket. The inner member has radially folded tapered segments in an unexpanded state that are mechanically unfolded and moved toward the inner wall of the elastomeric jacket by a medical device moving through the lumen of the inner member. The compressive outer elastomeric jacket returns the expanded inner member back to the radially folded, unexpanded state once the medical device has passed through the expanded lumen of the inner member. The structure can include a distal region that tapers to a rounded tip. The proximal region also tapers to mate with a hemostasis value housing.