Hybrid Atherectomy Cutter for Tight Lesions and Emboli Control
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Solution Overview
Problem
Current atherectomy devices struggle to effectively cut and remove various types of plaque, including calcified, necrotic, fibrotic, and soft plaque, while minimizing the risk of vessel injury and emboli release, and are inadequate for treating tight or tough lesions with minimal luminal opening.
Innovation Solution
The development of telescoping, self-driving, or lateral pushing atherectomy devices with hybrid cutters that can safely cut and remove different plaque types, self-collect debris, and treat tough lesions, featuring a cutter with a radius, helical flutes, and a reversibly-expandable lateral pushing member for enhanced maneuverability and plaque removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current atherectomy devices with rotating cutters are used, then they can remove plaque from blood vessels, but they cannot effectively handle all types of plaque (soft, fibrous, calcific) and may break up plaque into large pieces that remain as emboli
Solution Approach 1:
The cutter is designed with multiple cutting edges arranged in a segmented pattern around the cutter body, allowing simultaneous engagement with different types of plaque. The cutter body itself is segmented into distinct functional zones: a leading edge for soft plaque, intermediate edges for fibrous plaque, and a trailing edge with embedded elements for calcific plaque. This segmentation enables comprehensive plaque removal without requiring multiple devices.
Solution Approach 2:
The cutter employs composite construction with a rigid core material providing structural strength, overlaid with softer coating materials on the cutting edges that enhance plaque engagement and reduce plaque fragmentation. The composite structure allows the cutter to maintain integrity while effectively cutting through varied plaque compositions, minimizing emboli formation.
2Ease of manufacture
If balloon dilatation or stent placement is used, then traditional interventional treatment is provided, but the artery is stretched and scar tissue formation occurs leading to restenosis
Solution Approach 1:
The device extracts and removes the plaque material itself rather than compressing it against the vessel wall as in balloon angioplasty. The cutter physically excises the atherosclerotic burden from the arterial lumen, creating a clean cutting surface that heals without the scar tissue formation associated with mechanical compression or stent implantation.
3Reliability
If atherectomy devices are used on tight or tough lesions with minimal luminal opening, then plaque removal is attempted, but passage of the device through the lesion is difficult or impossible
Solution Approach 1:
The cutter assembly is designed with dynamic telescoping sections that allow the cutter diameter to be reduced during advancement through tight lesions. The cutter can be compressed to a smaller profile for navigation through occluded segments, then expanded to full diameter once positioned within the lesion for effective plaque removal. This dynamic size adjustment enables access to previously unreachable tight lesions.
4Reliability
If some state-of-the-art devices have burrs that can grind away hard plaque, then hard plaque removal is achieved, but soft or viscoelastic plaque cannot be cut and debris may become dangerous emboli
Solution Approach 1:
The cutter is designed as a universal cutting instrument that can effectively engage and remove all four major plaque types: soft, fibrous, calcific, and mixed. The multi-edge configuration with varying edge geometries and materials allows the single cutter to perform the functions previously requiring multiple specialized tools, while the contained cutting action minimizes debris generation across all plaque types.
5Reliability
If some state-of-the-art devices have a sharp cutter for eccentric cutting, then cutting capability is improved, but the amount of deflection cannot be effectively controlled
Solution Approach 1:
The cutter assembly incorporates controlled flexibility with inherent mechanical feedback that allows the cutter to deflect toward the vessel wall under cutting load, then return to center when the load is released. This passive feedback mechanism provides automatic deflection control without requiring active intervention, enabling effective eccentric cutting while maintaining positional stability.
Data Source
Figure 1A~1B
Figure 1C
Figure 2A~2B
AI summary
Telescoping, self-driving, and laterally-pushing atherectomy devices are provided, each having a flexible sheath, a cutter with helical flutes, and a drive assembly. The drive assembly can have a flexible driveshaft rotatably translational with the lumen of the flexible sheath, a positive displacement pump to transport cut tissue, and a flexible drive shaft that can be longer than the flexible sheath for a reversible telescoping of the drive assembly from the lumen of the flexible sheath. The positive displacement pump can be a screw pump having a drive screw portion exposed for contact with a vascular lumen for a self-driving of the device through the vascular lumen. A reversibly-expandable, lateral pushing member can be included at the distal end of the flexible sheath for a lateral pushing of the cutter. Improved cutting heads, and methods of making them, are provided for cutting a combination of soft and hard plaque.