Rotational Atherectomy Device Eccentric Abrasive Orbital Motion
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Solution Overview
Problem
Vascular access stenosis in hemodialysis patients leads to the formation of fibrous plaque-like lesions in implanted arteriovenous grafts, causing thrombosis and graft occlusion, which existing technologies struggle to effectively address.
Innovation Solution
The use of rotational atherectomy devices with an elongate flexible drive shaft and multiple eccentric abrasive elements, which rotate to abrade and break down stenotic lesions within the grafts, following a stable and predictable orbital path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rotational atherectomy devices are used to remove stenotic lesions in arteriovenous grafts, then blood flow is improved and graft occlusion is prevented, but the device complexity increases due to the need for stable and predictable orbital motion control
Solution Approach 1:
The patent employs asymmetric distribution of counterweights relative to the drive shaft axis to generate controlled orbital motion of the abrasive element. The counterweights are positioned at specific radial distances and angular orientations to create a stable orbiting profile that maintains contact between the abrasive element and the graft wall while removing stenotic lesions.
Solution Approach 2:
Counterweights are attached to the drive shaft at specific locations to balance the eccentric abrasive element and create a stable orbital motion pattern. The counterweights compensate for the unbalanced mass distribution, ensuring predictable orbital trajectories that improve reliability of lesion removal while maintaining device stability.
2Productivity
If multiple eccentric abrasive elements are used to abrade stenotic lesions, then the effectiveness of lesion removal is improved, but the manufacturing precision requirements increase to ensure stable orbital paths
Solution Approach 1:
The abrasive element is divided into multiple segments or lobes that are distributed around the drive shaft periphery. Each segment contributes to the orbital motion, and their combined action creates a stable orbiting pattern that enhances lesion removal effectiveness while the segmented structure provides inherent stability to the orbital path.
Solution Approach 2:
The patent optimizes parameters such as the radial distance of counterweights from the drive shaft axis, the angular positioning of multiple abrasive segments, and the mass distribution to achieve a stable orbital profile. By carefully controlling these parameters, the device achieves reliable orbital motion with predictable trajectories, reducing the impact of manufacturing tolerances.
3Ease of operation
If the abrasive elements follow a stable and predictable orbital path, then the safety and control of the procedure are improved, but the device design complexity increases
Solution Approach 1:
The counterweights and abrasive elements are pre-positioned on the drive shaft during manufacturing to establish the desired orbital characteristics before the procedure. This preliminary configuration ensures that when the device is activated, the abrasive element automatically follows a stable and predictable orbital path, improving procedure control without requiring complex real-time adjustments.
Solution Approach 2:
The device uses its own rotational motion and the pre-configured asymmetric mass distribution to automatically generate the orbital motion of the abrasive element. The system is self-regulating, where the centrifugal forces and gravitational effects on the counterweights naturally maintain the orbital profile, reducing the need for external control mechanisms and simplifying the overall device design.
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 solution effectively removes or reduces stenotic lesions in arteriovenous grafts, improving blood flow and preventing graft occlusion, while maintaining a stable and predictable rotary motion profile.
Implementation Method 1
rotating one or more abrasive elements to abrade and breakdown the lesion
Implementation Method 2
abrasive elements, which rotate to abrade and break down stenotic lesions
Data Source
AI summary
Rotational atherectomy devices and systems can remove or reduce stenotic lesions in implanted grafts by rotating one or more abrasive elements within the graft. The abrasive elements can be attached to a distal portion of an elongate flexible drive shaft that extends from a handle assembly that includes a driver for rotating the drive shaft. In particular implementations, individual abrasive elements are attached to the drive shaft at differing radial angles in comparison to each other (e.g., configured in a helical array). The centers of mass of the abrasive elements can define a path that fully or partially spirals around the drive shaft.