Retrieval Catheter Threaded Shaft Recapture Mechanism
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for deploying and retrieving collapsible prosthetic heart valves face challenges in precise placement and retrieval, particularly due to issues with axial alignment, paravalvular leaks, and interference with the heart's conduction system, and existing retrieval systems struggle with high compression forces required for recapturing partially deployed valves.
Innovation Solution
A retrieval catheter system is developed, featuring an inner tubular shaft with outer threads and an intermediate shaft with inner threads, allowing for controlled rotation to translate the shafts and a valve cover to recapture the prosthetic valve, along with a method involving a suture catheter and tethers to manage the valve's deployment and retrieval.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a collapsed prosthetic valve is delivered via catheter to avoid open-heart surgery, then invasiveness is reduced and surgical risks are lowered, but precise placement control and retrieval capability become more difficult
Solution Approach 1:
The delivery system is divided into multiple functional segments including an outer sheath for delivery, a valve cover for positioning, and a retrieval catheter with threaded shafts for recapture. This segmentation allows each component to perform its specific function optimally while maintaining overall system control.
Solution Approach 2:
The retrieval catheter acts as an intermediary device between the deployed valve and the delivery system. Its threaded inner and intermediate shafts provide mechanical engagement with the valve cover, enabling controlled recapture and retrieval without requiring open surgical intervention.
2Reliability
If the prosthetic valve is deployed at incorrect angle or position, then paravalvular leaks and turbulent blood flow occur, but adjusting position after deployment becomes difficult
Solution Approach 1:
The retrieval catheter is positioned and prepared for potential recapture before the valve is fully deployed. The threaded shafts are pre-assembled and ready to engage with the valve cover, allowing quick recapture if positioning adjustments are needed, thereby preventing permanent misplacement.
Solution Approach 2:
The system transitions from a static deployed state to a dynamic recapture state through the threaded engagement mechanism. Rotation of the intermediate shaft relative to the inner shaft translates the valve cover axially, enabling controlled repositioning or complete retrieval if placement errors are detected.
3Ease of operation
If high compression forces are applied to recapture a partially deployed valve, then the valve can be recaptured, but the risk of damage and procedural complexity increases
Solution Approach 1:
The system replaces direct high-force mechanical compression with a threaded screw mechanism. Rotation of the intermediate shaft converts rotational motion into controlled axial translation of the valve cover, gradually recapturing the valve with distributed forces rather than sudden high compression, thereby reducing damage risk.
Solution Approach 2:
The retrieval mechanism changes the force application parameter from high-magnitude compression to low-magnitude rotational torque. By rotating the intermediate shaft, the system generates controlled axial movement through thread engagement, transforming the recapture process into a gradual, controlled operation that protects valve integrity.
4Reliability
If the prosthetic valve is implanted at incorrect depth, then interference with the heart's conduction system occurs, but depth control during deployment is challenging
Solution Approach 1:
The system provides mechanical feedback through the threaded engagement between the inner and intermediate shafts. As the intermediate shaft rotates and translates the valve cover axially, the operator can feel and control the depth of engagement, enabling precise depth adjustment to prevent interference with the conduction system while ensuring proper valve positioning.
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 system enables precise deployment and retrieval of prosthetic heart valves, reducing the risk of leaks and conduction system interference, and facilitates the recapture of partially deployed valves with lower compression forces, improving procedural efficiency and safety.
Implementation Method 1
The inner surface in a distal portion of the intermediate tubular shaft has a series of inner threads engageable with the outer threads of the inner tubular shaft such that rotation of the intermediate tubular shaft relative to the inner tubular shaft translates the intermediate tubular shaft proximally or distally
Data Source
AI summary
A retrieval catheter for retrieving a partially deployed medical device held at the end of a catheter includes an inner shaft, an intermediate shaft and an outer shaft. The inner shaft engages the catheter in a manner that prevents translation of the inner shaft relative to the catheter. The intermediate shaft is assembled around the inner shaft and includes inner threads that engage with outer threads on the inner shaft such that rotation of the intermediate shaft translates it relative to the inner shaft and the catheter. The outer shaft is assembled around the intermediate shaft and includes a valve cover at its distal end. The valve cover is operatively connected to the intermediate shaft such that translation of the intermediate shaft translates the valve cover. Components of the medical device delivery system are disassembled from the catheter and the retrieval catheter is assembled thereover to retrieve the medical device.