Eccentric Grooved Atherectomy Head for Hydraulic Wedge Removal
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Solution Overview
Problem
Current atherectomy devices face limitations in effectively removing non-calcified and soft plaque due to hydraulic wedges forming between the abrasive and arterial walls, reducing contact and efficacy, and are unpredictable in procedure length and outcome when dealing with such lesions.
Innovation Solution
A rotational atherectomy device with an eccentric abrading head featuring axial and radial grooves on its surface, which breaks the hydraulic wedge and enhances contact with stenotic tissue, allowing for improved abrasion and removal of non-calcified and soft plaque, and is capable of opening arteries to a diameter twice that of its nominal resting diameter during high-speed rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a smooth abrasive surface is used in conventional atherectomy devices, then the device can be manufactured simply, but hydraulic wedges form between the abrasive and arterial walls, reducing contact and efficacy
Solution Approach 1:
The abrasive surface is designed with a porous structure containing multiple cavities and channels. This porous configuration allows blood and plaque debris to penetrate into the surface, preventing hydraulic wedge formation and improving contact between the abrasive and arterial walls, thereby enhancing abrasion efficacy while maintaining manufacturing feasibility
Solution Approach 2:
The abrasive surface features localized variations in porosity, cavity size, and channel distribution. Different regions of the surface have tailored pore structures optimized for specific functions: some areas promote fluid evacuation, while others enhance abrasive contact, creating locally optimized zones that collectively improve overall device reliability
2Device complexity
If a solid dense abrading head is used, then the structure is simple and strong, but it cannot open arteries to a diameter larger than its own diameter
Solution Approach 1:
The abrading head transitions from a static solid structure to a dynamic porous structure with fluid-filled cavities. During rotation, the porous structure allows for dynamic interaction with blood flow and plaque, enabling the effective opening diameter to exceed the physical diameter of the abrading head itself, thus improving productivity without significantly increasing structural complexity
Solution Approach 2:
The porous abrading head structure functions similarly to a flexible shell system, where the porous matrix and fluid-filled cavities allow for dynamic deformation and adaptation during rotation. This flexibility enables the structure to effectively engage and open arteries to diameters larger than the abrading head's nominal diameter
3Productivity
If high rotational speeds are used to improve abrasion efficiency, then plaque removal is enhanced, but heat generation and centrifugal forces increase
Solution Approach 1:
The porous structure incorporates fluid channels and cavities that facilitate hydraulic flow of blood and cooling fluids through the abrading head. This internal fluid circulation system actively removes heat generated during high-speed rotation, enabling sustained high rotational speeds for improved plaque removal efficiency while controlling temperature rise
Solution Approach 2:
The porous structure changes the thermal and fluid dynamic parameters of the abrading head. By introducing porosity and fluid pathways, the system alters heat transfer characteristics and fluid flow patterns, allowing high-speed operation with improved heat dissipation and reduced temperature buildup
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 achieves enhanced efficacy in removing non-calcified and soft plaque by breaking the hydraulic wedge and providing increased contact, resulting in more predictable procedure outcomes and longer effective treatment lengths.
Implementation Method 1
a burr covered with an abrasive abrading material such as diamond particles... When rotated at high speeds, the abrasive segment is capable of removing stenotic tissue from an artery
Implementation Method 2
the abrading head is rotated at high speeds (typically, e.g., in the range of about 150,000-190,000 rpm) while it is advanced across the stenosis
Data Source
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AI summary
The invention provides a rotational atherectomy system, device and method having, in various embodiments, a flexible, elongated, rotatable drive shaft with at least one eccentric abrading head attached thereto, wherein the abrading head comprises at least one groove thereon. The eccentric grooved abrading comprises a tissue removing surface--typically an abrasive surface and/or at least one groove. Preferably the eccentric enlarged abrading head has a center of mass spaced radially from the rotational axis of the drive shaft, facilitating the ability of the device to open the stenotic lesion to a diameter substantially larger than the outer diameter of the enlarged abrading head when operated at high speeds. The groove(s) provide improved efficacy in the abrasion of non-calcified and/or soft tissue as well as provide a means for breaking the hydraulic wedge between the abrading head and the stenotic tissue.