Catheter Blocking Mechanism for Guidewire Loop Control
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Solution Overview
Problem
Current devices for subintimal recanalization of chronic total occlusions in blood vessels face challenges in reliably advancing and re-entering the true lumen due to irregular artery shapes and the difficulty of penetrating bulky, calcified plaque, often resulting in unsuccessful re-entry and loss of guidewire loops.
Innovation Solution
A catheter system with a proximal, intermediate, and distal portion, including a blocking mechanism that allows for the formation of a loop in the guidewire within the subintimal space, enabling controlled re-entry into the true lumen by preventing distal advancement of the guidewire and using inflation to expand the blocking mechanism for precise perforation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a guidewire is advanced through the subintimal space to bypass a CTO lesion, then the guidewire can reach the distal side of the occlusion, but the guidewire loop may be lost or fail to re-enter the true lumen due to lack of control over loop position and orientation
Solution Approach 1:
The catheter incorporates a blocking mechanism at its distal end that can be selectively activated to prevent guidewire translation only at the re-entry site. This localized control allows the guidewire loop to be maintained in the desired configuration and orientation while permitting free movement elsewhere in the subintimal space.
Solution Approach 2:
The blocking mechanism is designed to be dynamically controllable, transitioning between blocked and unblocked states. This allows the operator to temporarily prevent guidewire translation when loop formation and orientation are critical, then release the block to allow guidewire advancement once proper positioning is achieved.
2Manufacturing precision
If conventional guidewires are used to penetrate bulky calcified plaque, then the guidewire must rely on operator skill to form loops, but rotation of the guidewire does not ensure proper loop direction and the loop may slide distally or be lost
Solution Approach 1:
The catheter serves as an intermediary device between the operator and the guidewire loop. By incorporating the blocking mechanism, the catheter actively manages loop positioning and orientation, reducing the complexity of manual guidewire manipulation while achieving precise loop orientation at the re-entry site.
3Measurement precision
If the guidewire loop is formed naturally by advancing forces, then the loop configuration is unpredictable and may not be directed toward the true lumen, but controlled loop formation requires preventing distal guidewire movement
Solution Approach 1:
The catheter is segmented into proximal and distal portions with different functionalities. The distal portion contains the blocking mechanism that selectively constrains guidewire movement, while the proximal portion allows free guidewire manipulation. This segmentation enables precise loop positioning without compromising overall guidewire advancement capability.
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 effectively facilitates re-entry into the true lumen distal to the occlusion, improving the success rate of subintimal recanalization by maintaining the guidewire loop configuration and ensuring proper orientation and penetration, thus enhancing blood flow restoration.
Implementation Method 1
a blocking mechanism disposed in the distal portion of the catheter, the blocking mechanism being transformable between a non-blocking configuration in which a guidewire is free to translate through the distal guidewire lumen and a blocking configuration in which a guidewire disposed in the distal guidewire lumen is prevented from translating through the distal guidewire lumen
Data Source
AI summary
A catheter for use with a subintimal reentry guidewire includes a proximal portion having a proximal guidewire lumen and a proximal inflation lumen, a distal portion having a distal guidewire lumen and a distal inflation lumen, and an intermediate portion disposed between the proximal portion and the distal portion and having an intermediate inflation lumen in fluid communication with the proximal and distal inflation lumens. The intermediate portion is devoid of a guidewire lumen. A blocking mechanism disposed in the distal portion of the catheter is transformable from a non-blocking configuration in which a guidewire is free to translate through the distal guidewire lumen and a blocking configuration in which a guidewire disposed in the distal guidewire lumen is prevented from translating through the distal guidewire lumen.