Top-Cap Assembly with Dynamic Closure for Stent Graft Retrieval
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Solution Overview
Problem
Existing endovascular delivery devices face challenges in accurately deploying and retrieving stent grafts due to the risk of dislodgment caused by the top-cap assembly's distally facing opening, which can engage with the deployed stent graft or vascular system components during withdrawal.
Innovation Solution
The design incorporates a top-cap assembly with a retriever assembly and a guide wire catheter, allowing the top-cap assembly to transition from an open to a closed configuration, ensuring the cavity is closed during withdrawal, and extending the outer tubular portion distally to cover the exposed stent, thereby preventing dislodgment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the top-cap assembly is designed with a distally facing opening for stent graft deployment, then the stent graft can be effectively deployed and retrieved, but the opening can engage with the deployed stent graft or vascular system components during withdrawal, causing dislodgment
Solution Approach 1:
The top-cap assembly is designed to dynamically change configuration from open to closed. The capsule can be advanced to close the distally facing opening, transforming the structure from a static open cavity to a dynamic closed configuration that prevents engagement with deployed stent graft components during withdrawal while maintaining deployment capability when open
2Ease of manufacture
If the capsule is left open during delivery device withdrawal, then the structure remains simple and easy to manufacture, but the open cavity can engage with and dislodge the stent graft from its position on the vascular wall
Solution Approach 1:
The capsule is designed with a preliminary closing mechanism that can be activated before withdrawal. The retriever assembly with body portion is positioned to automatically close the cavity opening as the delivery device is withdrawn, preventing harmful engagement with the stent graft before the dislodgment risk occurs
3Reliability
If the outer tubular portion is extended distally to cover the exposed stent, then the stent graft is protected from dislodgment, but the device complexity increases
Solution Approach 1:
The body portion of the retriever assembly is nested within the capsule structure, with the joiner portion integrating the outer tubular portion into the existing capsule design. This nesting approach provides the protective coverage function while minimizing additional complexity by utilizing and integrating with the existing capsule geometry rather than adding separate complex structures
Data Source
AI summary
An endovascular delivery device is disclosed. The device comprises a handle assembly at a distal end thereof and a top-cap assembly at a proximal end thereof. The top-cap assembly has an open configuration and a closed configuration and comprises: a capsule comprising an inner portion and an outer tubular portion and defining a cavity within the outer tubular portion, the cavity receiving the proximal portion of the endograft in the open configuration; and a retriever assembly having a body portion arranged and constructed to fit within the cavity of the capsule in the closed configuration. The device further comprises: a guide wire catheter extending through the handle assembly, the guide wire catheter being affixed at a proximal end thereof to the top-cap assembly; and an endograft receiving portion extending distally with respect to the top-cap assembly. In the closed configuration, the cavity is closed by the body portion of the retriever assembly.