Asymmetric Window Tissue-Removing Catheter
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Solution Overview
Problem
Atherectomy catheters face issues when the tissue-removing element becomes biased or off-axis during use, leading to potential damage to the catheter and non-functional devices due to contact with the catheter body.
Innovation Solution
A tissue-removing catheter with an asymmetric side opening window and a rotatable tissue-removing element that can move between a tissue-removing position and a neutral position, featuring a distal edge asymmetric about the longitudinal axis to prevent contact with the catheter body during movement, and a deployment mechanism that includes a ramp and cam system for guiding the cutter out of the window.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a rotatable cutting blade is advanced into occlusive material to cut and separate material from the blood vessel lumen, then tissue removal effectiveness is improved, but the risk of the blade becoming biased or off-axis increases, which can contact the catheter and cause damage
Solution Approach 1:
The cutting window is designed with an asymmetric distal edge that is offset from the longitudinal axis of the catheter body. This asymmetry creates a geometric configuration where the cutting blade, when rotating, cannot contact the catheter body even if it becomes biased or off-axis. The blade's path is constrained by the asymmetric window geometry, preventing damage to the catheter while maintaining effective tissue cutting capability.
2Reliability
If the tissue-removing element is positioned inside the distal portion of the catheter in a neutral position, then device safety is improved, but the ability to expose the blade for tissue removal is limited
Solution Approach 1:
The cutting blade is designed to be movable between a neutral position (retracted inside the catheter body for safety) and a tissue-removing position (exposed through the cutting window). This dynamic positioning allows the blade to be protected when not in use while being easily deployable when needed, resolving the contradiction between safety and operational capability.
Data Source
AI summary
A tissue-removing catheter for removing tissue from a body lumen includes an elongate catheter body configured for insertion into the body lumen and a tissue-removing element. A side opening in the distal portion of the catheter body is defined by opposite first and second side edges, a proximal edge extending between the first and second side edges, and a distal edge opposite the proximal edge and extending between the first and second side edges. The side opening window has a longitudinal axis extending between the distal and proximal edges. The tissue-removing element is configured to move between a tissue-removing position, in which the tissue-removing element is exposed through the side opening window, and a neutral position, in which the tissue-removing element is positioned inside the distal portion of the catheter. The distal edge is asymmetric about the longitudinal axis of the side opening window.