Eccentric Abrading Heads for Rotational Atherectomy
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Solution Overview
Problem
Existing rotational atherectomy devices face limitations in effectively removing stenotic material from arteries due to issues such as restricted diameter opening, heat generation, and imbalance, which can lead to stent restenosis and inadequate blood flow during procedures.
Innovation Solution
A rotational atherectomy device featuring a flexible, elongated drive shaft with eccentric abrading heads, where the centers of mass are radially offset from the rotational axis, allowing for high-speed operation and a debris-removing augering effect, enabling the device to open stenotic lesions to a diameter larger than the abrading heads' resting diameter and facilitating controlled debris removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a single burr is used to remove stenotic material, then the artery can be opened, but the opening diameter is limited to only slightly larger than the burr's maximum outer diameter
Solution Approach 1:
Multiple burrs (first burr and second burr) are combined into a single drive shaft assembly, allowing simultaneous operation of multiple abrasive elements. This merging approach enables the artery to be opened to a diameter larger than any single burr's maximum outer diameter would permit, while consolidating what would otherwise require multiple separate devices into one integrated system.
Solution Approach 2:
The drive shaft is segmented to include multiple distinct burrs (first burr with first maximum outer diameter, second burr with second maximum outer diameter) at different locations. This segmentation allows each burr to contribute differently to the overall opening process, enabling progressive dilation of the artery to achieve a final opening diameter exceeding that of any individual burr.
2Productivity
If high rotational speeds are used to remove stenotic material efficiently, then productivity increases, but heat generation and imbalance occur
Solution Approach 1:
The atherectomy device performs periodic cutting actions as the burrs rotate, with intervals between cutting events. This periodic operation allows heat to dissipate between cutting cycles, preventing excessive heat buildup while maintaining high average productivity. The burrs engage and disengage from the stenotic material in a rhythmic pattern during rotation.
Solution Approach 2:
The cutting function is divided among multiple burrs (first burr, second burr) rather than concentrating all cutting action in a single element. This segmentation distributes the heat generation across multiple smaller contact points, reducing localized heat buildup while maintaining overall productivity through combined action of all burrs.
3Volume of moving object
If multiple burrs are used to open the artery to a larger diameter, then the opening diameter improves, but the device complexity increases
Solution Approach 1:
The drive shaft serves multiple functions simultaneously: it transmits rotational power to multiple burrs, provides structural support for the burr assembly, enables navigation through the vasculature, and facilitates the opening of the artery to a diameter larger than any single burr's maximum outer diameter. This multi-functionality consolidates what would otherwise require separate components into a single universal device.
Solution Approach 2:
Multiple burrs with different maximum outer diameters are merged into a single integrated drive shaft assembly, allowing them to operate cooperatively. The first burr and second burr work in combination to open the artery to a diameter that exceeds the maximum outer diameter of either burr individually, while the merged structure reduces overall device complexity compared to using separate devices.
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 effectively opens stenotic lesions to a larger diameter than previous devices, reduces stent restenosis risk, and enhances debris removal through a spiral channeling effect, improving procedural efficiency and patient outcomes.
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 asymmetrical burr is rotated at lower speeds than are used with high speed ablation devices, to compensate for heat or imbalance... the center of mass offset from the rotational axis of the drive shaft would result in development of significant centrifugal force
Data Source
AI summary
The invention provides a rotational atherectomy device having, in various embodiments, a flexible, elongated, rotatable drive shaft with a system of eccentric abrading heads attached thereto. At least part of the eccentric enlarged abrading heads in the system have a tissue removing surface—typically an abrasive surface. In certain embodiments, the abrading heads may be at least partially hollow. Preferably the eccentric enlarged abrading heads have centers of mass spaced radially from the rotational axis of the drive shaft, facilitating the ability of the system of eccentric abrading heads to work together to open the stenotic lesion to a diameter substantially larger than the outer resting diameter of the enlarged abrading heads when operated at high speeds. Therefore, certain embodiments comprise a system having unbalanced centers of mass to not only stimulate greater rotational diameters but also arranged in a manner whereby a debris-removing augering effect occurs. Alternatively, other embodiments may comprise systems having abrading heads with balanced centers of mass.