Contra-rotating Cutting Assembly for Atherectomy
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Solution Overview
Problem
Current atherectomy devices face limitations in effectively capturing and removing occlusive material, leading to particle residue and embolization in downstream vessels, and may cause hemolysis or arterial wall damage.
Innovation Solution
A contra-rotating cutting assembly with a rotatable cutter head and housing, capable of rotating in opposite directions, which reduces cutter-induced swirl and enhances material capture by canceling out radial velocity components of excised particles, thereby improving embolic capture performance and allowing for more effective clearing of occlusions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single rotating cutter is used to remove occlusive material, then cutting action is achieved, but particle residue and embolization occur in downstream vessels
Solution Approach 1:
The single rotating cutter is segmented into two contra-rotating cutters that rotate in opposite directions. This segmentation allows each cutter to perform cutting while the opposing rotation cancels out radial velocity components, reducing particle dispersion and embolization risk while maintaining effective occlusive material removal
Solution Approach 2:
The second cutter is positioned to rotate in the opposite direction to the first cutter, creating a preliminary counteracting action. The radial velocity components generated by each cutter oppose and cancel each other, preventing the harmful effect of particle residue and embolization before particles can be carried downstream
2Productivity
If high rotational speed is used to clear occlusions quickly, then productivity increases, but arterial wall damage and hemolysis occur
Solution Approach 1:
The contra-rotating cutters create opposing radial velocity fields that cancel each other out. This preliminary anti-action neutralizes the harmful effects of high-speed rotation on the arterial wall and blood cells, allowing high productivity to be achieved without causing hemolysis or vessel damage
Solution Approach 2:
The second cutter acts as a counterweight to the first cutter, with its opposite rotation creating counterbalancing forces. This counteraction reduces the net radial velocity impact on surrounding tissues, enabling high-speed operation without the harmful effects of arterial wall damage and hemolysis
3Quantity of substance
If expandable cutters with foldable wings and vacuum aspiration are used, then material capture is improved, but arterial wall perforation occurs
Solution Approach 1:
The harmful vacuum aspiration system and foldable wings are extracted from the design. Instead, the invention uses a simple rotating cutter configuration that captures material through the cutting action itself, eliminating the mechanisms that cause arterial wall perforation while maintaining effective plaque removal
Solution Approach 2:
The material capture function is segmented into the cutting action of the contra-rotating cutters themselves, rather than relying on a separate vacuum system. The cutters remove and contain material through their rotational cutting motion, achieving effective capture without the need for vacuum aspiration that could cause wall perforation
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 contra-rotating cutting assembly increases the amount of material captured, reduces particle loss, and enhances the ability to clear long total occlusions in a single pass with minimal clogging, improving the effectiveness of atherectomy devices.
Implementation Method 1
The housing is configured to rotate about a longitudinal axis in a first direction, and the cutter head is configured to rotate about the longitudinal axis in a second direction opposite the first direction
Data Source
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AI summary
The invention generally relates to intraluminal procedures, and, more particularly, to a contra-rotating cutting assembly for use with an atherectomy device to remove occlusive material from an occluded lumen, such as a blood vessel or other body lumen. The contra- rotating cutting assembly includes a rotatable housing having a distal end, an opposing proximal end and a lumen extending between the distal and proximal ends. The housing is configured to rotate about a longitudinal axis in a first direction. The cutting assembly further includes a rotatable cutter head positioned within at least a portion of the lumen of the housing and in coaxial alignment with the housing. The cutter head is configured to rotate about the longitudinal axis in a second direction opposite the first direction.