Expandable Stent Sidewall for Annular Perfusion in Large Vessels
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing balloon catheters face challenges in maintaining perfusion in larger vessels like the aorta due to the difficulty in creating a large perfusion lumen while maintaining a rounded shape and applying even radial force, leading to issues such as myocardial ischemia and increased procedure risk during procedures like TAVR.
Innovation Solution
The design of expandable devices with tubular sidewalls that bow out of alignment during expansion, creating buckled regions to form an annular perfusion lumen, allowing blood flow past the balloon while maintaining radial force on tissue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a large perfusion lumen is created in larger vessels like the aorta, then adequate distal perfusion can be maintained, but the catheter cannot maintain a rounded shape and apply even radial force
Solution Approach 1:
The catheter sidewall is segmented into multiple regions with varying thickness, creating distinct structural zones. The thinner regions form the perfusion lumen openings while the thicker regions maintain the rounded external shape, allowing both large perfusion area and rounded geometry to coexist.
Solution Approach 2:
Different portions of the catheter sidewall have different local properties - some areas are thinned to create perfusion lumens while other areas maintain full thickness for structural support and rounded shape. This local variation in wall thickness allows simultaneous achievement of large perfusion area and rounded geometry.
2Area of stationary object
If a large perfusion lumen is created in larger vessels, then adequate distal perfusion can be maintained, but even radial force cannot be applied to tissue
Solution Approach 1:
The catheter wall is segmented into load-bearing regions and perfusion regions. The thicker segments maintain structural integrity to apply radial force, while thinner segments create perfusion lumens. This segmentation allows the catheter to simultaneously provide both radial force and large perfusion area.
Solution Approach 2:
Local variations in wall thickness create regions of different mechanical properties. Thicker regions provide the structural support needed for radial force application, while thinner regions allow blood flow. This local quality differentiation resolves the contradiction between perfusion area and radial force.
3Productivity
If conventional balloon catheters are used in larger vessels, then procedure can be performed, but myocardial ischemia and increased procedure risk occur
Solution Approach 1:
The catheter is designed with pre-formed perfusion lumens and variable wall thickness before deployment. This preliminary structural configuration allows perfusion to be established before the balloon inflation procedure, preventing myocardial ischemia from the outset while enabling procedure completion.
Solution Approach 2:
The variable thickness sidewall design provides continuous perfusion capability throughout the procedure by maintaining open lumens that do not require balloon deflation. This continuous perfusion action eliminates the harmful effects of intermittent ischemia while allowing uninterrupted procedure execution.
Data Source
AI summary
Expandable devices are disclosed herein. Several of the embodiments are directed towards an expandable device comprising a stent configured to be expanded within a body conduit of a human patient. The stent may comprise a tubular sidewall having first portions and second portions. Radial expansion of the stent may cause the first portions to bow outwardly and out of radial alignment with the second portions.