Expandable Flow-Diverter for Tortuous Vessels
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Solution Overview
Problem
Current flow-diverting stents and braids face challenges in achieving a snug fit across the neck of aneurysms located in curved, twisted, or forked vessels, often resulting in crimping, kinking, inadequate porosity, and unintended blockage of blood flow to branching vessels.
Innovation Solution
An expandable flow-diverting device comprising a frame with interconnected struts and a flow-diverting mesh, designed to be flexible and self-expanding, which can conform to tortuous vessel shapes while maintaining apposition with the vessel walls and inhibiting blood flow into aneurysms through controlled porosity and pore size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If current flow-diverting stents or braids are used in tortuous vessels, then the device can be positioned in curved, twisted, or forked vessels, but the device suffers from crimping or kinking and achieves inadequate porosity
Solution Approach 1:
The device is divided into multiple independently expandable segments or cells that can be compressed for delivery and then expand individually to conform to the tortuous vessel shape. This segmentation allows the device to navigate curved and twisted vessels without crimping or kinking, while maintaining proper porosity in each segment.
Solution Approach 2:
The device incorporates dynamic expansion characteristics where the struts are designed to expand radially and flexibly to match the local vessel geometry. This dynamic adaptation enables the device to conform to tortuous vessel paths while maintaining structural integrity and adequate porosity for flow diversion.
2Reliability
If current flow-diverting stents or braids are expanded to block blood flow, then the aneurysm can be treated, but blood flow to branching or secondary vessels is undesirably blocked
Solution Approach 1:
The device incorporates varying porosity or strut density in different regions. The portion spanning the aneurysm neck has higher porosity for effective flow diversion, while adjacent portions have lower porosity or are designed to preserve flow to branch vessels. This local differentiation allows selective flow blocking where needed while maintaining perfusion to healthy tissues.
Solution Approach 2:
The device utilizes variable porosity parameters across different sections of the stent. By adjusting the pore size, strut thickness, or cell density locally, the device can achieve high flow diversion in the aneurysm region while maintaining adequate flow through adjacent branch vessels, thus treating the aneurysm without causing harmful ischemia.
3Adaptability or versatility
If the device is made flexible to fit tortuous vessels, then the device can conform to vessel shapes, but the device may not maintain adequate porosity when expanded
Solution Approach 1:
The device is constructed with segmented strut patterns or cellular structures that maintain uniform porosity across each segment while allowing overall flexibility. This segmentation ensures that even when the device conforms to tortuous vessel paths, each local region maintains consistent pore dimensions and porosity for effective flow diversion.
Solution Approach 2:
The device design incorporates porosity parameters that are independent of the device's bent or twisted configuration. The strut geometry and cell dimensions are engineered to expand to consistent sizes regardless of the vessel's curvature, ensuring that porosity is maintained even when the device is highly flexible and conforms to tortuous paths.
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 device effectively reduces blood flow into aneurysms, promoting thrombosis and healing while allowing perfusion to adjacent branch vessels, and can be accurately placed in smaller blood vessels due to its flexibility and design.
Implementation Method 1
Expandable devices can be delivered into vascular system to divert flow... the expandable device can be expandable to an expanded state at an aneurysm
Implementation Method 2
a plurality of pores located between the struts... a plurality of pores in the sidewall that are sized to inhibit flow of blood through the sidewall into an aneurysm
Data Source
Figure 1A
Figure 1B
Figure 1C~1D
AI summary
Devices that can be delivered into a vascular system to divert flow are disclosed herein. According to some embodiments, devices are provided for treating aneurysms by diverting flow. A flow-diverting device can comprise, for example, a frame and mesh immovably attached to and extending over a portion of the frame. The mesh can include a plurality of pores that are sized to inhibit the flow of blood through the frame into an aneurysm to a degree sufficient to lead to thrombosis and healing of the aneurysm when the device is positioned in a blood vessel and adjacent to the aneurysm.