Variable Flow Stent With Self-Healing Valve

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Solution Overview

Problem

Current stents used in TIPS procedures and other vascular interventions lack the ability to adjust diameter reliably, leading to imbalances between internal bleeding and blood toxicity, which can vary over time, necessitating adjustments during or after initial intervention.

Innovation Solution

A variable flow stent design featuring a cylindrical wire mesh with an expandable secondary chamber and self-healing valve, allowing for controlled blood flow adjustment via inflation or deflation using a catheter and needle, with a radiopaque collar for precise valve location, and an expandable jack device with microhooks for snagging stent walls.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a stent is used to divert portal venous blood into general circulation, then internal bleeding is reduced, but blood toxicity increases

Engineering Contradiction:

Improveinternal bleedingVSAvoidblood toxicity

Core Design Contradiction:

Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The stent incorporates an inflatable balloon within its structure that can dynamically adjust the stent's diameter. By inflating the balloon, the stent diameter decreases, limiting blood flow and reducing toxicity. By deflating the balloon, the stent diameter increases, improving blood flow and reducing internal bleeding. This dynamic adjustment capability allows the system to adapt to changing patient needs and resolve the contradiction between reducing internal bleeding and minimizing blood toxicity.

Inventive Principle:

Principle #15Dynamics

2Ease of operation

If a fixed diameter stent is used, then the procedure is simple, but the blood flow cannot be adjusted to balance internal bleeding and toxicity

Engineering Contradiction:

Improveprocedure simplicityVSAvoidblood flow adjustability

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

The stent transitions from a fixed diameter design to a dynamic adjustable design through the incorporation of an inflatable balloon mechanism. The balloon can be inflated or deflated via catheter insertion through the skin, allowing non-invasive adjustment of the stent diameter and blood flow characteristics, thus providing adaptability while maintaining operational simplicity.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The stent system includes a self-healing valve that automatically seals after needle puncture, eliminating the need for complex sealing mechanisms or additional procedural steps. This self-service feature simplifies the adjustment procedure while enabling repeated blood flow modifications.

Inventive Principle:

Principle #25Self-service

3Adaptability or versatility

If the stent diameter is adjusted during or after the initial intervention, then blood flow can be optimized, but the device complexity increases

Engineering Contradiction:

Improveblood flow optimizationVSAvoidstent structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The inflatable balloon is nested within the stent structure, with the balloon contained inside the stent's cylindrical framework. This nesting arrangement allows the balloon to expand and contract the stent diameter without requiring external mechanisms or complex assembly, thus enabling blood flow optimization while minimizing structural complexity.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The self-healing valve acts as an intermediary mechanism that simplifies the interaction between the external catheter/needle and the internal balloon system. The valve automatically seals after puncture, mediating the connection between the external adjustment mechanism and the internal inflatable structure, thereby reducing the overall system complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

Enables controllable and adjustable blood flow in TIPS, dialysis grafts, and AV fistulas, allowing for necessary adjustments to balance internal bleeding and blood toxicity by narrowing or widening the stent lumen as required, thereby improving treatment efficacy and safety.

Implementation Method 1

The self-healing valve may include a self-healing membrane

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

a radiopaque collar concentrically disposed around the self-healing valve for assistance in locating the self-healing valve

Methodology Applied

Scientific EffectX-Ray: X-Ray

Data Source

PatentUS11672681B2Variable flow stent

Publication Date: 2023.06.13 SYED MUBIN I

AI summary

A variable flow stent is described for use with AV fistulas, TIPS procedures or dialysis grafts. The flow may be varied by adjusting the diameter of the stent. Embodiments include: a covered stent having a secondary chamber that functions as an air or fluid bladder; an expandable chamber within an interior stent covering; a retractable jack device with hooks that engage (snag) opposing walls of the stent; and, a stent with a hollow chamber or pocket in the interior stent covering into which an expandable balloon can be inserted. A self-healing valve is described for inflating or deflating expandable elements within the stent and may be implemented using a self-healing membrane. A radiopaque collar may be used to provide a marker surrounding the self-healing valve. If under-shunting or over-shunting occurs over time, the variable diameter stent may be adjusted using a second procedure.