Tissue-removing Catheter Locking Control Mechanism
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Solution Overview
Problem
Atherectomy catheters face challenges when treating in-stent restenosis, as they often entangle with stents, leading to malapposition or damage, particularly due to the entanglement of the rotating cutter and stent, which is a concern for existing side-cutting catheters like SilverHawk and TurboHawk.
Innovation Solution
The development of an operational control mechanism for a tissue-removing catheter that includes a distal portion with a locking shuttle mechanism and a motor control mechanism to prevent entanglement by detecting and responding to the hardness of the material being cut, reducing power to the cutter when engaging a stent or hard tissue, and a locking control mechanism to inhibit movement if a stent is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a rotating cutter is used to remove tissue from the blood vessel, then tissue removal effectiveness is improved, but entanglement with stent occurs leading to malapposition or damage
Solution Approach 1:
The cutter is designed to be movable between a retracted position and an extended cutting position, allowing dynamic adjustment of the cutter's location and operational state based on tissue hardness detection, thereby preventing entanglement with stents while maintaining effective tissue removal capability
Solution Approach 2:
A feedback mechanism detects the hardness of material being cut and automatically adjusts cutter operation by reducing power or locking the cutter in position when stent material is detected, preventing entanglement while allowing effective cutting of softer atheromatous tissue
2Productivity
If the cutter rotates at high speed to efficiently remove plaque, then productivity is improved, but the risk of entanglement with stent increases
Solution Approach 1:
The system takes preliminary action by detecting material hardness before significant entanglement can occur, and preemptively reduces cutter power or locks the cutter position when stent material is detected, preventing the harmful entanglement effect before it develops
Solution Approach 2:
Real-time feedback on material hardness allows the system to dynamically adjust cutter rotation speed and position, maintaining high productivity on soft plaque while automatically reducing speed or locking when stent is encountered, thereby preventing entanglement
3Adaptability or versatility
If the cutter is allowed to move freely to access different tissue areas, then adaptability is improved, but the risk of damaging stent or causing malapposition increases
Solution Approach 1:
The cutter's position is made dynamic, allowing free movement to access different tissue areas when needed, but automatically locking in a safe position when stent material is detected, thereby balancing adaptability with stent protection
Solution Approach 2:
The control mechanism acts as an intermediary between the operator's positioning commands and the actual cutter movement, allowing adaptive positioning while mediating to prevent movements that would cause stent entanglement or damage
Data Source
AI summary
A tissue-removing catheter includes a sensor configured to detect a parameter of the catheter during the cutting operation of the catheter when a tissue-removing element is in a tissue-removing position. A locking control circuit is in electrical communication with the sensor and a locking device. During an operational control function, the locking control circuit receives a signal from the sensor based at least in part on the parameter of the catheter detected during the cutting operation of the catheter. The locking control circuit determines whether the received signal is indicative of a tissue-removing element engaging a non-tissue obstruction. The locking control circuit configures the locking device in its locked configuration to inhibit movement of the tissue-removing element from its tissue-removing position to its neutral position if the received signal is indicative of the tissue-removing element engaging a non-tissue obstruction.