Helical Cutter Atherectomy Device for Plaque Removal
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Solution Overview
Problem
Current endovascular procedures for treating occluded body lumens, such as atherosclerosis, face challenges in safely and efficiently removing occlusive materials, particularly in the peripheral vasculature where stents often fail due to mechanical stress and are ineffective in maintaining lumen diameter over time.
Innovation Solution
A vascular device with a catheter body and a cutter assembly featuring a helical cutting surface and conveyor mechanism, which allows for controlled cutting and removal of occlusive material without a vacuum pump, and includes a deflecting mechanism for navigating tortuous vessels and bifurcations, enabling effective debulking and patency restoration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If balloon angioplasty is used to expand and open the artery by compressing plaque, then the lumen diameter is increased, but barotrauma to the vessel wall occurs leading to high restenosis rates
Solution Approach 1:
The atherectomy device extracts and removes occlusive plaque material from the vessel lumen through cutting and aspiration mechanisms, rather than compressing it as in balloon angioplasty. This extraction approach opens the lumen without subjecting the vessel wall to high-pressure barotrauma, thereby reducing restenosis risk while maintaining lumen diameter.
2Force
If a stent with high structural integrity is used to supply sufficient radial force to reopen the artery, then the radial force is adequate, but the stent fails under mechanical stress in peripheral vasculature
Solution Approach 1:
The stent is designed with dynamic characteristics including variable strut thickness and adjusted radial stiffness along its length, allowing it to adapt to varying mechanical stresses in peripheral vasculature. This dynamic design enables the stent to maintain adequate radial force for vessel reopening while withstanding compression, torsion, and bending forces through optimized structural flexibility.
3Area of stationary object
If a stent with high radial force is used to open the vessel, then the lumen is adequately opened, but the stent cannot withstand compression and torsion in peripheral vasculature
Solution Approach 1:
The stent incorporates local quality variations with different strut thicknesses and material properties at different locations along the stent length. This allows regions requiring high radial force to have thicker, stronger struts while regions requiring flexibility to withstand compression and torsion have thinner, more compliant struts, achieving both adequate lumen opening and mechanical durability.
4Loss of substance
If conventional atherectomy devices are used to cut plaque, then plaque removal is achieved, but debris embolization may occur
Solution Approach 1:
An intermediary aspiration system with a distal aspirating catheter is introduced as a mediator between the cutting element and the bloodstream. This intermediary mechanism captures plaque debris at the cutting site through coordinated aspiration during rotation, preventing debris from entering circulation and causing embolization while maintaining effective plaque removal.
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 device enables safe and efficient removal of occlusive material, reducing restenosis and maintaining lumen diameter, while withstanding biomechanical stresses, thus improving long-term patency and reducing complications like embolization and thrombosis.
Implementation Method 1
a cutter having at least one helical cutting surface configured to rotate about the central axis relative to the housing to cut and convey the occlusive material from the body lumen proximally into the housing
Implementation Method 2
a conveyor mechanism helically wound about the torque shaft in a direction common with the helical cutting blade to convey the occlusive material conveyed into the housing by the helical cutting blade further proximally along the catheter body
Data Source
AI summary
A vascular device is provided having a catheter body and a rotatable cutter assembly located at the distal end of the catheter body. The cutter assembly has at least one helical cutting surface within a housing that is coupled by a torque shaft to a drive mechanism. A conveyor mechanism helically wound about the torque shaft conveys occlusive material conveyed into the housing by the helical cutting blade further proximally along the catheter body for discharge without supplement of a vacuum pump. The catheter body is manipulated to insert the distal end of the catheter body within a body lumen and advance the distal end of the catheter body toward the occlusive material. The drive mechanism is operated to rotate the helical cutting surface to cut and convey the occlusive material from the body lumen proximally into the housing and to convey the occlusive material conveyed into the housing by the helical cutting surface further proximally along the catheter body by the conveyor mechanism for discharge without supplement of a vacuum pump. The distal end of the catheter body is deflected and rotated to sweep the cutter assembly in an arc about the center axis of the catheter body to cut occlusive material in a region larger than the outside diameter of the cutter assembly.