Stent Graft Delivery System With Control Tether
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Solution Overview
Problem
The placement and orientation of stent grafts can be variable due to the intermediate to final diameter transition during deployment, which may result in the stent graft landing in an unintended position or orientation, especially in sensitive areas like the aorta, due to blood flow and other factors.
Innovation Solution
A controlled expansion stent graft delivery system that includes a fabric tube attached to a self-expanding stent with loops for a control tether, allowing for adjustable tension to manage the expansion and positioning of the stent graft, using a retractable sheath and a delivery catheter with a tether clamp to control the expansion and ensure precise placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the stent graft is allowed to self-expand from intermediate to final diameter, then the stent graft can be deployed, but the placement precision and orientation control deteriorate due to the jump between diameters and blood flow impact
Solution Approach 1:
The patent employs a dynamic control mechanism where the stent graft's expansion state can be actively adjusted during deployment. The delivery system maintains the stent graft in a constrained intermediate diameter state initially, then allows controlled transition to final diameter. This dynamic control enables the clinician to pause expansion at the critical transition point, observe positioning, and make adjustments before final expansion, thereby resolving the contradiction between placement precision and deployment simplicity.
2Measurement precision
If the stent graft is constrained to a secondary diameter during delivery, then the device can be positioned, but the final landing zone variability increases due to the jump to final diameter
Solution Approach 1:
The patent applies preliminary action by pre-positioning the stent graft in a constrained intermediate diameter state within the delivery system before release. The delivery system is designed to maintain this constrained state during navigation to the target site. Only after proper positioning is achieved does the system allow transition to the final expanded diameter. This preliminary constrained positioning action ensures accurate landing zone placement while maintaining trajectory control throughout the deployment process.
3Productivity
If the stent graft expands quickly to final diameter, then the deployment is efficient, but the orientation control is lost due to blood flow and other factors affecting trajectory
Solution Approach 1:
The patent implements periodic action by dividing the expansion process into distinct phases: an initial constrained phase where the stent graft remains in intermediate diameter during positioning, followed by a controlled expansion phase. This periodic control allows the clinician to first establish proper orientation and position while the device is constrained, then initiate expansion only after orientation is confirmed. This phased approach maintains both deployment efficiency and orientation control by preventing premature expansion.
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
Enables precise control over the expansion and positioning of the stent graft, allowing for accurate placement and orientation within the vessel, reducing variability and ensuring the stent graft reaches its intended landing zone.
Implementation Method 1
a self expanding stent
Data Source
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AI summary
A controlled expansion stent graft delivery system has an adjustment configuration in which a retractable sheath is at a retracted position out of contact with a stent graft, but expansion of the stent graft is controlled by a control tether, which has a middle segment wrapped around a fabric tube of the stent graft. The stent graft changes diameter responsive to a tension level in the control tether. At least one of an orientation and a position of the stent graft may be adjusted during controlled expansion via the control tether.