Segmented Arcuate Cutter for Tissue Removal in Tortuous Vessels
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Solution Overview
Problem
Existing atherectomy catheters face challenges in accessing and removing atheromatous materials from small, tortuous vascular regions in a controlled manner, particularly in coronary and peripheral arteries, due to varying tissue properties such as softness, fibrosis, and calcification.
Innovation Solution
A rotatable cutter with a central hub, flutes, and arcuate cutting members is designed for a tissue-removing catheter, featuring a raised leading cutting edge and a recessed clearance portion to facilitate cutting and dislodging tissue, allowing for effective removal of occlusive materials from body lumens, including arteries and other vascular regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a rotatable cutting blade is used to cut atheromatous material, then tissue removal capability is improved, but control and safety in small tortuous vessels deteriorates
Solution Approach 1:
The cutter is segmented into multiple discrete cutting members (three arcuate cutting members spaced around the circumference) rather than using a single continuous blade. Each cutting member has its own raised element with leading cutting edge, allowing the cutter to effectively engage and remove various types of atheromatous material while maintaining control in tortuous vessels through the distributed cutting action
Solution Approach 2:
The cutter employs a rotatable design that can spin during operation, transforming the static cutting edges into dynamic cutting elements. The rotation allows the cutting members to engage the atheromatous material from multiple angles and positions, improving tissue removal capability while the overall cutter remains controllable through the catheter delivery system in tortuous vasculature
2Productivity
If cutting members are positioned close together to remove tissue effectively, then tissue removal efficiency is improved, but interference between adjacent cutting members worsens
Solution Approach 1:
Each cutting member has a localized raised element with a leading cutting edge positioned at a specific location. The raised elements create localized cutting zones that are spaced apart, allowing each cutting member to engage tissue independently without interfering with adjacent cutting members. The recessed clearance portions between raised elements further ensure spatial separation of cutting zones
Solution Approach 2:
The cutting members are arranged in the circumferential dimension around the cutter's axis, with three arcuate cutting members spaced approximately 120 degrees apart. This circumferential distribution in a different dimension allows effective tissue removal around the entire circumference while maintaining sufficient spacing to prevent interference between adjacent cutting members during rotation
3Ease of manufacture
If the cutter design is simplified for manufacturing, then ease of manufacture is improved, but adaptability to different tissue types deteriorates
Solution Approach 1:
The cutter design allows for parameter variations in the cutting members to adapt to different tissue types. The arcuate cutting members can be manufactured with different radial heights, arc lengths, or spacing configurations depending on the specific application requirements for soft versus fibrous or calcified plaque. The basic three-member arcuate structure provides a manufacturable baseline that can be customized through parameter adjustment
Data Source
AI summary
A rotatable cutter for a tissue-removing catheter includes a central hub, flutes spaced apart from one another around the circumference of the central hub, and arcuate cutting members. Each cutting member includes an arcuate cutting edge extending along an arc length of the cutting member for cutting tissue as the cutter is rotated. A raised element of each cutting member has a leading cutting edge at a leading end of the distal cutting member for cutting tissue as the cutter is rotated. A clearance portion of each cutting member is recessed, relative to the longitudinal axis of the cutter, from the raised element and extends from the raised element to a trailing end of the cutting member to provide clearance for the leading cutting edge of an adjacent and opposing distal cutting member.