Contra-Rotating Atherectomy Cutter for Plaque Debulking
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Solution Overview
Problem
Current endovascular procedures for clearing blood vessel obstructions, such as atherosclerosis, face challenges with inefficient plaque removal, high rates of restenosis, and stent failure due to mechanical stress in peripheral vasculature, particularly in elastic plaque and calcified lesions.
Innovation Solution
The development of a vascular device with a flexible body and a cutter assembly that includes a rotating shaft and a deflecting member, allowing for controlled and safe removal of occlusive materials through multiple cutting surfaces and a grinding burr, which can navigate tortuous anatomy and maintain vessel patency with reduced trauma.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a stent with high structural integrity is used to supply sufficient radial force to reopen the artery, then the radial force is improved, but the stent fails in the harsh mechanical environment of the peripheral vasculature due to compression, torsion, extension, and bending
Solution Approach 1:
The cutting assembly is divided into multiple independent cutting surfaces (first cutting surface, second cutting surface, third cutting surface) that can rotate and engage the occlusive material sequentially, allowing controlled debulking without requiring excessive mechanical force from a single cutting edge
Solution Approach 2:
The cutting assembly incorporates rotation capability and adjustable positioning of cutting surfaces, transforming a static cutting tool into a dynamic system that can adapt to different plaque configurations and reduce mechanical stress on the vessel wall during the procedure
2Productivity
If a rotating cylindrical shaver or fluted cutter is used to cut away plaque, then plaque removal is achieved, but debris may dislodge and embolize downstream vessels
Solution Approach 1:
The cutting assembly is nested within a housing that contains the rotating cutter, and debris is captured within the housing structure during rotation, preventing embolization while maintaining efficient plaque removal through the nested containment approach
Solution Approach 2:
A housing structure serves as an intermediary between the rotating cutter and the vessel lumen, containing the cutting action and capturing debris before it can enter the bloodstream, while still allowing effective plaque debulking to occur
3Area of stationary object
If balloon angioplasty is used to expand and open the artery by compressing plaque, then luminal diameter is increased, but barotrauma to the vessel wall occurs leading to high rates of restenosis
Solution Approach 1:
The patent replaces the high-pressure compression mechanism of balloon angioplasty with a mechanical cutting and debulking system that removes occlusive material through rotation and cutting action, avoiding barotrauma to the vessel wall while achieving luminal patency
4Productivity
If the cutter rotates within the housing, then plaque is cut away, but the cutting edges may contact the vessel wall causing injury
Solution Approach 1:
The housing is positioned and oriented before the cutting action begins, with cutting surfaces exposed at strategic locations that are predetermined to engage only occlusive material and not the vessel wall, preventing injury before it can occur
Solution Approach 2:
Different portions of the housing have different properties - some areas are open to expose cutting surfaces for plaque removal, while other areas provide shielding to protect the vessel wall, creating localized zones of cutting action separated from zones of protection
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
This solution enables effective and controlled removal of occlusive materials, reducing restenosis and stent failure by providing a safer, more efficient method for maintaining vessel patency and allowing for the use of stents with reduced mechanical stress, thereby improving long-term vascular health.
Implementation Method 1
a cutter having at least one cutting surface configured to rotate relative to the housing, where movement of the cutting surface relative to the vessel removes occlusive material
Implementation Method 2
a deflecting member extending along the catheter body, such that the deflection member can cause deflection of the cutter assembly relative to an axis of the catheter
Data Source
Figure 1A~1B
Figure 1C~2C
Figure 3A~3B
AI summary
The invention relates 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 positioned within at least a portion of the lumen of the housing and in coaxial alignment with the housing. The cutter is configured to rotate about the longitudinal axis in a second direction opposite the first direction.