Curvable Stent-Graft With Tightenable Loop for Aortic Arch Sealing
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Solution Overview
Problem
The deployment of stent-grafts in highly curved lumens, such as the aortic arch, often results in incomplete sealing due to improper placement, leading to blood leakage and premature fatigue failure, and is limited by the need for a sufficient length of healthy vascular wall, excluding treatment of aneurysms with short necks or excessive curvature.
Innovation Solution
A compressible and curvable stent-graft with a tightenable loop of thread, featuring a self-tightening knot, allows for precise curvature adjustment to fit the aortic arch, ensuring better sealing and positioning, and an introducer assembly with a pull cord and release element facilitates this curvature during deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stent-graft is deployed in a highly curved lumen such as the aortic arch using conventional methods, then the device can be delivered to the treatment site, but the proximal end becomes incorrectly fitted resulting in incomplete sealing and blood leakage
Solution Approach 1:
The stent-graft is pre-curved in a controlled manner during the manufacturing process using a curving apparatus, so that when it is deployed in the aortic arch, it already has the necessary curvature to achieve proper sealing. This preliminary curving action eliminates the need for post-deployment adjustment and ensures the proximal end fits correctly against the vessel wall.
Solution Approach 2:
The curvature of the stent-graft is changed as a key parameter during deployment. By controlling the curvature radius and orientation of the stent-graft before deployment, the device can adapt to the curved geometry of the aortic arch, ensuring proper contact and sealing with the vessel wall at the proximal end.
2Adaptability or versatility
If conventional stent-graft deployment methods are used in highly curved lumens, then the procedure can be performed, but a reasonable length of healthy vascular wall is required which limits treatment availability
Solution Approach 1:
The stent-graft is pre-curved during manufacturing to match the expected anatomy of the aortic arch. This preliminary curving allows the device to be deployed in patients with short segments of healthy vascular wall, as the pre-curved configuration enables adequate sealing without requiring extended healthy wall length for anchoring.
Solution Approach 2:
The stent-graft incorporates a curving mechanism that allows dynamic adjustment of its shape during deployment. The device can transition from a straight configuration during delivery to a curved configuration at the treatment site, adapting to the specific curvature of the patient's aortic arch and enabling treatment in cases with limited healthy vascular wall.
3Reliability
If the stent-graft is not fitted precisely in the correct location, then the procedure may need to be repeated or aborted, but repeating increases operating time and trauma to the patient
Solution Approach 1:
The stent-graft is pre-positioned and pre-curved in a controlled manner during the deployment process using a curving apparatus. This preliminary preparation ensures that when the device is released, it is already in the correct position and orientation, eliminating the need for time-consuming repositioning attempts and reducing the risk of procedure abandonment.
4Ease of operation
If the proximal end of the stent-graft remains loosely located in the vessel, then deployment is simplified, but premature fatigue failure and thrombus effects occur
Solution Approach 1:
The stent-graft is pre-curved and pre-positioned during deployment using the curving apparatus, so that when released, it immediately achieves the correct configuration for secure anchoring. This preliminary action ensures proper contact with the vessel wall from the outset, preventing loose positioning that would lead to fatigue failure or thrombus formation.
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 solution enables precise placement and self-retention of the stent-graft in a curved configuration, improving sealing and reducing the need for lengthy healthy vascular wall, thus expanding treatment options for aneurysms with short necks or complex geometries.
Implementation Method 1
a compressible and curvable structure; a tightenable loop of thread, the tightenable loop including a first end closed in a knot and a second end passing through the knot and able to slide therein at least in a loop tightening direction, the loop being fitted to the device such that tightening of the loop causes the device to curve
Data Source
AI summary
A stent-graft (100) is provided with a tightenable loop element (122) having a first end terminated in a self-tightening knot (142) and a second end (138) which is received in and can slide in the knot (142). The loop (122) is fitted to the stent-graft (100) in a manner as to cause curvature of the stent-graft (100) upon tightening of the loop. An introducer assembly is also disclosed which includes a cannula (132, 150) within which a pull cord (136) and release wire (134) are located.