Atherectomy Device Cutter Deflection and Debris Conveyance
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Solution Overview
Problem
Current endovascular procedures for clearing occlusions in blood vessels, such as atherectomy and balloon angioplasty, face challenges including high rates of restenosis, inefficiency in treating plastic-type plaque, and stent failure due to harsh mechanical environments in the peripheral vasculature, which necessitate improved devices for safe and efficient removal of occlusive materials.
Innovation Solution
The development of advanced atherectomy devices with features like a flexible body, rotating cutter assemblies, deflecting members, and conveying mechanisms that allow for controlled removal and navigation through tortuous anatomy, along with the option of using a burr for grinding calcified lesions, to prevent vessel wall damage and maintain patency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If balloon angioplasty is used to expand and open the artery by compressing plaque, then the artery lumen is opened, but barotrauma to the vessel wall occurs leading to high rates of restenosis
Solution Approach 1:
The patent replaces the balloon compression mechanism with a mechanical cutting system (rotating cutter or burr) that physically removes plaque through abrasion and cutting actions, eliminating the need for high-pressure balloon inflation that causes barotrauma
Solution Approach 2:
The invention extracts and removes the harmful plaque material from the artery through a cutting or grinding mechanism, rather than compressing it in place, thereby opening the lumen without subjecting the vessel wall to traumatic pressures
2Force
If a stent with sufficient radial force is used to reopen the artery, then the artery is opened adequately, but the stent fails in the harsh mechanical environment of the peripheral vasculature
Solution Approach 1:
The patent changes the mechanical parameters of the stent by using softer, more compliant materials that can deform and adapt to the dynamic peripheral vasculature environment, sacrificing some radial force for improved flexibility and durability
Solution Approach 2:
The invention introduces dynamic characteristics to the stent design, allowing it to flex, bend, and adapt to the movement and deformation of peripheral vessels, transforming a static rigid structure into a dynamic compliant one
3Productivity
If a rotating cutter is used to excise plaque, then plaque removal is effective, but debris may embolize downstream vessels
Solution Approach 1:
The patent introduces an intermediary aspiration system that acts as a mediator between the cutting action and the downstream vasculature, capturing debris at the source and transporting it away through the catheter lumen to prevent embolization
Solution Approach 2:
The invention uses pneumatic or hydraulic aspiration forces to create negative pressure that draws debris into the catheter lumen during cutting, utilizing fluid dynamics to control and remove particulate matter
4Strength
If the cutter housing is made rigid for structural integrity, then the device maintains shape, but it cannot navigate tortuous anatomy
Solution Approach 1:
The patent divides the catheter structure into segmented sections with varying degrees of flexibility, allowing the proximal portion to be rigid for structural support while the distal portion remains flexible for navigation through tortuous vessels
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
These devices enable safe, efficient, and controlled removal of occlusive materials, reducing the risk of restenosis and stent failure, while maintaining vessel patency and allowing for the use of stents with reduced radial force, thus addressing the limitations of existing technologies.
Implementation Method 1
a cutter having at least one cutting surface configured to rotate relative to the housing, where movement between the housing opening and the cutting surface removes material located therebetween
Implementation Method 2
a deflecting member extending along the catheter body, such that movement of the deflecting member causes deflection of the cutter assembly relative to an axis of the catheter
Implementation Method 3
a conveying member extending through the catheter body and configured to convey the material away from the operative site
Data Source
AI summary
The devices and methods generally relate to treatment of occluded body lumens. In particular, the present devices and methods relate to controlled removal of the occluding material from the blood vessels as well as other body lumens. The atherectomy devices have features to convey the materials away from the operative site without the need to remove the devices from the body lumen. Additional aspects include controlled rates of tissue removal as well as other safety features to prevent accidental cutting of the lumen wall.