Negative-Pressure Covered Stent Delivery for Low-Friction Thrombus Capture
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Solution Overview
Problem
Current stent delivery systems face challenges in effectively advancing self-expanding stents through narrow and tortuous vasculature due to friction, and aspiration catheters struggle to capture thrombi across vessel diameters, leading to incomplete recanalization and thrombus detachment during withdrawal.
Innovation Solution
A covered stent with a gas-impermeable membrane and a frame that can be radially expanded using a pressure differential, where reducing pressure within the stent's lumen counteracts the outward force of the frame, reducing friction and facilitating advancement to the thrombus, and then expanding to capture it.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a self-expanding stent is advanced through narrow and tortuous vasculature, then the stent can reach the thrombus location, but friction between the stent and vasculature wall impedes advancement
Solution Approach 1:
The patent applies parameter changes by controlling the pressure differential across the stent membrane. By maintaining negative pressure (lower pressure inside than outside), the stent is compressed radially inward, reducing its diameter and friction with the vasculature wall during advancement. Once deployed, the pressure differential is reduced or reversed, allowing the stent to expand radially outward to its full diameter for thrombus capture.
2Strength
If the stent frame exerts radially outward force to expand the stent, then the stent can capture the thrombus, but friction increases and impedes advancement through the vasculature
Solution Approach 1:
The patent implements dynamics by making the stent's radial force dynamic rather than static. The stent frame continuously exerts radially outward force, but the actual expansion state is dynamically controlled by the pressure differential. During advancement, negative pressure keeps the stent compressed despite the frame's outward force. After deployment, reducing the negative pressure allows the frame's outward force to expand the stent for thrombus capture.
3Ease of operation
If a narrow aspiration catheter is used to access the vasculature, then the catheter can navigate tortuous vessels, but it cannot ingest a thrombus that spans across the blood vessel
Solution Approach 1:
The patent applies the nesting principle by placing the covered stent inside a delivery catheter system. The stent is delivered through a narrow catheter in a compressed state, allowing navigation through tortuous vessels. Once positioned at the thrombus, the stent is deployed and expands radially outward beyond the catheter, creating a large opening that can engulf and capture the thrombus, effectively combining the advantages of both narrow delivery and large capture capacity.
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 system enables efficient advancement and deployment of the stent to the thrombus, enhancing recanalization success by minimizing friction and ensuring complete thrombus capture without detachment.
Implementation Method 1
reducing pressure within the stent's lumen counteracts the outward force of the frame, reducing friction and facilitating advancement
Implementation Method 2
gas-impermeable membrane
Data Source
AI summary
A first guide tube can be advanced through a patient's vasculature, and a covered stent that can be radially expandable from a compressed state to an expanded state and comprise a frame configured to urge the covered stent toward the expanded state when the stent is in the compressed state, a gas-impermeable membrane coupled to the frame, and a lumen surrounded by the gas-impermeable membrane can be advanced through the first guide tube while pressure within the covered stent's lumen is reduced. After advancing the covered stent through the first guide tube, the covered stent can be expanded from the compressed state to the expanded state at least by positioning the covered stent relative to the first guide tube such that at least a portion of the covered stent is disposed distally of the first guide tube's distal end and increasing pressure within the covered stent's lumen.