Expandable Introducer Sheath Interlock for Controlled Expansion and Removal
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Solution Overview
Problem
Existing introducer sheaths for intracardiac blood pumps are prone to tearing, require excessive force for removal, and lead to vascular complications due to their non-expandable nature, while expandable sheaths risk clot formation and kinking during prolonged use.
Innovation Solution
An expandable introducer sheath with an interlock dilator system, featuring a step feature and catch surface engagement, allows for controlled expansion and retraction, minimizing vessel damage and clot formation, and integrating with a dilator hub for tension maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a non-expandable peel away introducer sheath is used, then the sheath can be easily removed by peeling, but the sheath tears too easily or requires excessive force to remove, leading to bleeding or vascular complications
Solution Approach 1:
The introducer sheath is designed to be radially expandable from a compressed delivery configuration to an expanded use configuration. This dynamic transformation allows the sheath to adapt its diameter during the procedure, providing structural integrity during insertion while maintaining ease of controlled removal without premature tearing or excessive force requirements.
Solution Approach 2:
The sheath undergoes parameter changes in its radial dimension, transitioning from a small compressed diameter for delivery to a large expanded diameter for use. This parameter change enables the sheath to provide adequate support and fixation during the procedure while allowing for controlled removal without causing vascular complications.
2Ease of operation
If the introducer sheath inner diameter is large enough to accommodate the largest diameter portion of the pump assembly, then the pump assembly can pass through, but the sheath creates an opening wider than necessary, complicating vessel closure
Solution Approach 1:
The introducer sheath dynamically changes its diameter by expanding from a compressed to an expanded configuration. During delivery, the sheath remains compressed with a small diameter that matches the vessel size. When needed, it expands to accommodate the pump assembly. After device insertion, the sheath can be removed without leaving a permanently enlarged opening, simplifying vessel closure.
Solution Approach 2:
The sheath function is segmented into delivery phase (compressed state) and use phase (expanded state). This segmentation allows the sheath to provide adequate support during device passage while minimizing the opening size during delivery and facilitating easier vessel closure after procedure completion.
3Adaptability or versatility
If an expandable sheath is used to allow passage of the device, then the sheath can expand radially, but the sheath may kink or buckle during insertion or withdrawal due to flexibility
Solution Approach 1:
The introducer sheath is constructed from composite materials that combine radial expandability with structural stability. The composite structure provides the necessary rigidity to prevent kinking and buckling during insertion and withdrawal while maintaining the ability to expand radially when needed to accommodate the device.
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
An expandable introducer sheath with an interlock dilator. The present technology provides an expandable sheath with a step feature inside its distal opening, and a dilator with an interlock that includes a catch surface that is configured to engage with the step feature of the expandable sheath. When the step feature engages the catch surface, it resists further relative movement so that the body of the dilator is prevented from exiting the distal end of the expandable sheath. The nature of the interlocking engagement between the step feature and the catch surface allows the dilator to be used to extend and maintain tension on the expandable sheath during insertion into a patient, and then to be retracted from the expandable sheath by simply pulling the dilator in the opposite direction. The present technology also provides a dilator hub with a spring mechanism configured to achieve and maintain a desired tension on the expandable sheath and to prevent overextension of the expandable sheath when the dilator is being inserted into the expandable sheath.