Eccentric Abrading Element for High-Speed Rotational Atherectomy
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Solution Overview
Problem
Existing rotational atherectomy devices are limited in their ability to effectively remove stenotic material due to restricted diameter opening and lack of control over the abrading process, particularly in cases with calcified lesions, as they often require multiple burrs and struggle with stent restenosis, and fail to achieve high-speed rotation without causing trauma or heat issues.
Innovation Solution
A high-speed rotational atherectomy device featuring a flexible, elongated drive shaft with an asymmetric, partially spherical abrading element that positions its center of mass eccentrically, allowing for orbital motion and enhanced diameter opening beyond the device's resting diameter, facilitated by a helically coiled wire construction and adjustable mass distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional burr is rotated at high speeds to remove stenotic tissue, then tissue removal capability is improved, but the artery is opened only to a diameter equal to or slightly larger than the maximum outer diameter of the burr, limiting the effectiveness of the procedure
Solution Approach 1:
The burr is designed with an eccentric configuration where the center of mass is offset from the geometric center, creating asymmetric mass distribution. This asymmetry causes the burr to describe an orbital path during rotation, enabling it to open the artery to a diameter larger than its own maximum outer diameter, thus resolving the contradiction between tissue removal capability and diameter opening.
Solution Approach 2:
The invention introduces orbital motion as an additional dimension of movement beyond simple rotation. By combining rotational motion with eccentric offset, the burr creates a three-dimensional orbital path that allows it to effectively enlarge the artery diameter beyond what would be possible with conventional rotational motion alone.
2Volume of moving object
If multiple burrs of different sizes are used to open the artery to the desired diameter, then the diameter opening is improved, but the procedure complexity and time are increased
Solution Approach 1:
The eccentric burr design provides multi-functionality by enabling a single burr size to achieve multiple diameter openings through variation in rotational speed and orbital path. This eliminates the need for multiple burrs of different sizes, thereby reducing procedure complexity while maintaining the ability to open the artery to the desired diameter.
3Productivity
If the burr is advanced across the stenosis to remove tissue, then tissue removal is improved, but blood flow is blocked during the procedure
Solution Approach 1:
The high-speed rotational atherectomy device removes stenotic tissue rapidly through the orbital motion of the eccentric burr, minimizing the time the burr is present in the artery. This rushing through the stenosis reduces the duration of blood flow blockage while maintaining effective tissue removal capability.
4Productivity
If high-speed rotation is used to remove stenotic material, then productivity is improved, but trauma and heat generation increase
Solution Approach 1:
The invention changes the motion parameters from simple rotation to orbital motion with variable speed. By controlling the rotational speed and orbital path, the system achieves high productivity in tissue removal while distributing the mechanical stress over a larger area and longer duration, thereby reducing peak trauma and heat generation compared to conventional high-speed rotation.
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
Enables effective removal of stenotic material to a diameter larger than the device's resting diameter, with controlled orbital motion and reduced trauma, allowing for improved blood flow and stent patency while maintaining high-speed operation without excessive heat or particle size issues.
Implementation Method 1
When placed against stenotic tissue and rotated at high speed, the eccentric nature of the abrading element moves along an orbital path
Implementation Method 2
a burr covered with an abrasive abrading material such as diamond particles
Data Source
AI summary
The invention provides a rotational atherectomy device having, in various embodiments, a flexible, elongated, rotatable drive shaft with at least one asymmetric and at least partially spherical abrading element attached thereto, which comprises an abrasive surface. The abrading element comprises more mass above the drive shaft than below and comprises a flattened side or transverse surface which creates hard cutting edges and spaces the center of mass radially from the rotational axis of the drive shaft. Thus the center of mass is moved vertically and transversely by the structure of the abrading element, conferring geometric and mass eccentricity upon the element. When placed against stenotic tissue and rotated at high speed, the eccentric nature of the abrading element moves along an orbital path, opening the lesion to a diameter larger than the resting diameter of the abrading element.