Medical Device Securing via Locking Wire and Sheath
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Solution Overview
Problem
Current methods for deploying balloon expandable medical devices, such as stents and transcatheter heart valves, face issues like device movement during insertion, potential flaring at the distal end, and risk of piercing the balloon due to shoulder-based securing mechanisms.
Innovation Solution
A method and assembly that secure a crimped medical device over a deflated balloon catheter using rings at the device ends, strings with eyelets, and a locking wire, which minimizes movement and flaring, and prevents balloon piercing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If shoulders are used to secure the medical device on the balloon, then the device is held in place during delivery, but the device may pierce the balloon due to movement and pressure against the shoulders
Solution Approach 1:
A sheath is introduced as an intermediary component between the medical device and the balloon. The sheath covers the device during delivery and prevents direct contact between the device shoulders and the balloon, thereby eliminating the piercing risk while maintaining secure device positioning
Solution Approach 2:
The securing mechanism is divided into separate functional components: the sheath provides protection and guidance, while the strings with eyelets and locking wire provide the securing function. This segmentation allows each component to perform its specific function without causing harm
2Ease of operation
If the medical device is exposed during insertion, then the device can be delivered to the treatment location, but the device experiences movement and may flare at the distal end
Solution Approach 1:
The sheath serves as a mediator that guides the device during insertion while maintaining device stability. It prevents flaring at the distal end and allows controlled delivery to the treatment location without exposing the device to harmful movements
Solution Approach 2:
The device is pre-secured to the balloon using strings and locking wire before insertion. This preliminary securing action prevents device movement and flaring during the delivery process, while the sheath provides additional protection during insertion
Data Source
AI summary
A method and an assembly for securing a crimped medical device over a deflated balloon of a balloon catheter is provided. The medical device is positioned in its expanded state over the deflated balloon of the balloon catheter, and is then crimped over the deflated balloon. First and second eyelets of first and second strings, respectively, are then threaded through first and second rings, respectively, that are provided on the medical device. Next, a locking wire is advanced through a lumen defined between the sheath and the catheter body to exit the distal end of the sheath, and then advanced through the first and second eyelets and into the distal tip of the balloon catheter. The sheath is then advanced over the crimped medical device to the distal tip to completely cover the crimped medical device.