Expandable Introducer Sheath Interlock for Tensioned Pump Insertion
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Solution Overview
Problem
Existing introducer sheaths for intracardiac heart pumps are not radially expandable, leading to issues such as excessive vessel opening, tearing, vascular complications, and thrombosis, especially during prolonged use, and require multiple sheaths for insertion and repositioning, complicating procedures and increasing risks.
Innovation Solution
An expandable introducer sheath with an interlock dilator system, featuring a step feature and catch surface for secure engagement, allowing tensioned insertion and retraction, and a spring mechanism to maintain sheath expansion, reducing the need for multiple sheaths and minimizing vessel damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a non-expandable introducer sheath is used, then the sheath structure is simple and easy to manufacture, but the inner diameter must be large enough to accommodate the pump assembly, creating excessive vessel opening and requiring multiple sheaths for insertion and repositioning
Solution Approach 1:
The sheath is designed with expandable characteristics, transitioning from a compressed delivery state to an expanded deployed state. The sheath body includes expandable features such as radial expandability that allow it to change diameter dynamically during the procedure, eliminating the need for excessive initial diameter while maintaining adequate access during use
Solution Approach 2:
The sheath is delivered in a compressed state within a delivery system, nested within other components during insertion, then expanded at the target site. This allows the sheath to fit through small access points while providing adequate working diameter when deployed, avoiding the need for multiple sheaths
2Ease of operation
If a peel away introducer sheath is used, then the sheath can be removed, but it tears too easily or requires excessive force, leading to bleeding, vascular complications, or inadvertent pump position shift
Solution Approach 1:
The sheath includes preliminary engagement features such as barbs or anchoring mechanisms that secure the sheath to the vessel wall or pump assembly before removal is attempted. This preliminary anchoring allows for controlled removal when needed while preventing accidental dislodgement during the procedure
Solution Approach 2:
The sheath is constructed from composite materials or multi-layer structures that provide both strength and controlled tear characteristics. The material composition allows the sheath to resist tearing during normal use and pump insertion while enabling deliberate removal when required, balancing integrity with removability
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 that complicates vessel closure
Solution Approach 1:
The sheath maintains an expanded configuration during the procedure to provide adequate access, then can be collapsed or compressed to a smaller profile during removal. This dynamic size adjustment allows the vessel opening to be minimized after sheath removal, facilitating easier closure and reducing complications
Solution Approach 2:
The sheath is designed to be temporarily deployed and then removed after serving its purpose of facilitating pump insertion. The removal mechanism allows for clean extraction without leaving excessive tissue disruption, and the sheath materials are chosen to minimize tissue damage and facilitate healing
4Object-affected harmful factors
If an expandable sheath is used, then the inner diameter can be smaller initially, but the sheath requires complex expansion mechanisms and may cause thrombosis during prolonged use
Solution Approach 1:
The expandable features are localized to specific portions of the sheath rather than the entire structure. Only the distal or critical access portions require expansion capability, while proximal portions remain simpler. This localized approach reduces overall complexity while maintaining the benefits of reduced initial diameter and adequate local access
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 system provides a single sheath solution that minimizes vessel trauma, reduces bleeding, maintains access, and simplifies procedures by eliminating the need for multiple sheaths, while maintaining guidewire access and reducing thrombosis risk.
Implementation Method 1
a spring mechanism to maintain sheath expansion
Data Source
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 configured to engage with the step feature and resist further relative movement so that the body of the dilator is prevented from exiting the distal end of the expandable sheath. This interlocking engagement may allow 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 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.