Expandable Catheter Tip Sealing for Clot Retrieval
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Solution Overview
Problem
Existing devices are inadequate for effectively removing acute blockages such as clots from blood vessels, particularly in cases of acute ischemic stroke, myocardial infarction, and pulmonary embolism, without causing further complications.
Innovation Solution
A catheter system with a distal end that expands to seal against the vessel wall and a large open mouth for clot reception, combined with a flow restrictor to facilitate aspiration, and optionally a microcatheter for clot capture, allowing for efficient clot removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a catheter is used to aspirate clot from a vessel, then clot removal capability is improved, but risk of dislodging clot and causing embolism increases
Solution Approach 1:
The catheter mouth is expanded before clot engagement to create a larger reception area, allowing the clot to be gently guided into the catheter rather than forcefully extracted, thereby reducing the risk of dislodgement while maintaining effective clot removal capability
Solution Approach 2:
The catheter mouth is made expandable and movable between retracted and expanded configurations, allowing dynamic adaptation to the clot size and vessel geometry, enabling safe engagement and retrieval of clots of varying sizes without excessive force that could cause dislodgement
2Productivity
If aspiration flow is increased to improve clot removal efficiency, then productivity increases, but risk of vessel damage and embolism increases
Solution Approach 1:
The flow restrictor is positioned locally at the distal end of the catheter to restrict flow only in the region where the clot is being engaged, while allowing unrestricted flow elsewhere in the vessel, enabling efficient local clot removal without compromising overall vessel integrity
Solution Approach 2:
The flow restrictor acts as an intermediary element between the aspiration source and the clot, modulating the aspiration flow to achieve optimal clot engagement forces while preventing excessive flow that could damage the vessel or dislodge the clot
3Productivity
If catheter diameter is increased to improve clot reception capacity, then clot removal capability is improved, but device complexity and difficulty of insertion increase
Solution Approach 1:
The catheter mouth is designed to be dynamically expandable from a small delivery profile to a large reception opening, allowing the catheter to be easily inserted through narrow access paths while providing large clot reception capacity upon deployment at the target site
Solution Approach 2:
The expandable mouth structure is nested within the catheter body in a compact configuration for delivery, similar to a nested doll, and only expands to its full reception capacity when deployed at the target site, minimizing insertion difficulty while maximizing clot reception ability
4Device complexity
If flow restrictor is positioned proximal to the distal segment to simplify structure, then device complexity is reduced, but aspiration effectiveness distal to the restrictor decreases
Solution Approach 1:
The flow restrictor is positioned proximal to the distal segment to preliminarily restrict flow before it reaches the distal clot engagement region, creating a controlled flow environment that enhances aspiration effectiveness while maintaining structural simplicity
Solution Approach 2:
The flow restrictor positioned proximal to the distal segment serves as an intermediary that indirectly controls flow conditions at the distal end, achieving effective clot aspiration while maintaining a simpler overall device structure compared to placing the restrictor at the distal tip
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 effective clot retrieval with minimal risk of dislodging the clot and preserves vessel access for additional passes, enhancing the safety and efficacy of clot removal procedures.
Implementation Method 1
a flow restrictor located on the outer surface of the catheter distal of the transfer port
Implementation Method 2
The mouth may be defined by an expansile tip
Implementation Method 3
a catheter for assisting in the retrieval of a clot from a vessel
Data Source
Figure 1
Figure 2a~2c
Figure 2d~2f
AI summary
A catheter 101 provides a proximal seal 102 against a guide catheter inner lumen 103 so that aspiration may be applied through a guide catheter 108 and thus take advantage of the large proximal lumen. The catheter 101 is a rapid exchange (RX) catheter with an exit port 105 that defines a transfer port for aspiration and provides a deliverability advantage of minimal frictional engagement with the guide catheter 108 proximal of the exit port 105. Aspiration can be applied to the lumen of the guide catheter 108 and is directed to and effective at the tip of the Rx aspiration catheter 101 due to the presence of flow a restrictor or seal 102 between the outer surface of the Rx aspiration catheter 101 and the inner guide catheter 108. This seals the lumen between the outside of the Rx aspiration catheter 101 and the inner surface of the guide catheter 103 and prevents backflow of blood into the tip of guide catheter 108 reducing the effectiveness of the aspiration. An expansile tip 112 of the Rx catheter 101 facilitates aspiration and retrieval of the clot 110 by expanding under load. The expansile tip 112 can also partially or fully occlude the vessel providing flow arrest and thereby improving aspiration effectiveness.