Stent with Berms for AAA Landing Zone Extension
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Solution Overview
Problem
The existing stenting procedures for abdominal aortic aneurysms (AAAs) face challenges due to inadequate landing zones, leading to endoleaks caused by blood seepage through gutters between non-conforming stent and chimney graft walls, which limits the effectiveness of the chimney technique.
Innovation Solution
A fluid-permeable tubular stent body with longitudinally separated ends, defining primary and secondary lumens, and fluid-impermeable berms to prevent lateral fluid flow, combined with fluid-impermeable chimney grafts that extend into renal arteries, creating a longer landing zone and preventing endoleaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If chimney grafts are placed in renal arteries to extend landing zone, then landing zone length is improved, but gutters are created between grafts and aorta allowing endoleak
Solution Approach 1:
The stent body is made fluid-permeable, allowing blood to flow through it rather than creating gutters. This eliminates the endoleak problem by permitting controlled fluid passage while maintaining structural integrity and sealing against the aortic wall.
Solution Approach 2:
The stent is nested within the chimney graft structure, with the stent's secondary lumens positioned within the graft lumen. This nested arrangement allows the stent to provide internal support and sealing while the graft extends the landing zone externally.
2Object-affected harmful factors
If longer chimney grafts are used to reduce endoleak, then endoleak is reduced, but maximum length is limited by distance to SMA orifice
Solution Approach 1:
The stent introduces a new spatial dimension with secondary lumens that extend into the aorta beyond what a single longitudinal graft can achieve. This allows effective landing zone extension without being constrained by the linear distance to the SMA orifice.
Solution Approach 2:
The stent body is segmented into multiple lumens (primary and secondary) that can independently interact with different anatomical structures. This segmentation allows flexible configuration to achieve adequate landing zone extension while avoiding obstruction of visceral arteries.
3Object-affected harmful factors
If stent body is made fluid-permeable to allow blood flow, then endoleak is prevented, but structural strength may be reduced
Solution Approach 1:
The stent body combines fluid-permeable material with sufficient structural strength to maintain its cylindrical shape and resist collapse while allowing blood flow through its walls. The composite structure provides both permeability for endoleak prevention and strength for mechanical support.
Data Source
AI summary
A stent includes a fluid-permeable stent body having longitudinally separated proximal and distal stent ends. The stent body has inner and outer stent body surfaces. The stent body defines at least one longitudinally extending primary lumen and at least two longitudinally extending secondary lumens laterally spaced from one another with at least a portion of the primary lumen interposed laterally therebetween. The secondary and primary lumens all are at least partially fluid-permeable between the inner and outer stent body surfaces. At least one fluid-impermeable and longitudinally extending berm is located directly laterally adjacent a corresponding secondary lumen. The berm prevents fluid flow laterally between at least a portion of the corresponding secondary lumen and a space laterally opposite the secondary lumen beyond the berm. A method of using the stent in at least partially extending a superior landing zone of an abdominal aortic aneurysm is also described.