TIPS Stent Graft with Adjustable Central Section

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Solution Overview

Problem

Existing TIPS stent grafts do not allow for post-placement adjustments in diameter, leading to issues such as hepatic encephalopathy due to excessive blood flow bypassing the liver.

Innovation Solution

A TIPS stent graft with a balloon expandable central section and self-expanding sections, equipped with a constriction means such as a shape memory alloy collar or a coil, allowing for selective reduction or expansion of the stent graft's diameter post-placement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If the TIPS stent graft diameter is increased to reduce portal pressure, then portal hypertension is adequately treated, but hepatic encephalopathy occurs due to excessive blood flow bypassing the liver

Engineering Contradiction:

Improveportal pressureVSAvoidhepatic encephalopathy

Core Design Contradiction:

Stress or pressureVSObject-affected harmful factors

Solution Approach 1:

The stent graft incorporates a constriction means that can be activated after implantation to dynamically reduce the diameter of the stent graft. This dynamic adjustment capability allows the system to adapt to changing physiological conditions, reducing blood flow when hepatic encephalopathy occurs while maintaining adequate portal pressure reduction

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention changes the physical parameter of stent graft diameter post-implantation through the constriction means. By mechanically reducing the diameter parameter after initial deployment, the system can optimize blood flow characteristics to prevent hepatic encephalopathy while maintaining effective portal hypertension treatment

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If the TIPS stent graft diameter is reduced to treat hepatic encephalopathy, then blood flow through the liver is increased, but portal hypertension may not be adequately treated

Engineering Contradiction:

Improvehepatic encephalopathyVSAvoidportal pressure

Core Design Contradiction:

Object-affected harmful factorsVSStress or pressure

Solution Approach 1:

The reversible nature of the constriction means enables dynamic adjustment of stent graft diameter in both directions. This allows clinicians to optimize the balance between reducing hepatic encephalopathy risk and maintaining adequate portal pressure reduction by adjusting the diameter based on patient response

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system enables feedback-based adjustment where clinical outcomes (presence of hepatic encephalopathy, portal pressure levels) inform subsequent adjustments of the constriction means, allowing optimization of the diameter parameter based on actual physiological response

Inventive Principle:

Principle #23Feedback

3Ease of manufacture

If a fixed diameter stent graft is used, then the device is simple and easy to manufacture, but post-placement adjustments cannot be made to optimize patient outcomes

Engineering Contradiction:

Improvedevice simplicityVSAvoidpost-placement adjustability

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The stent graft is divided into functional segments: a fixed diameter section for structural support and a variable diameter section with the constriction means. This segmentation allows the majority of the device to remain simple while providing a specific adjustable portion for post-placement optimization

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The constriction means acts as an intermediary mechanism between the fixed stent graft structure and the desired variable diameter function. This intermediary component enables adjustability without requiring the entire stent graft to be complex or actively controllable

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 bidirectional adjustability of the stent graft's diameter to optimize blood flow through the liver, reducing the incidence of hepatic encephalopathy and improving patient survival by allowing for dynamic adjustment of portal pressure.

Implementation Method 1

the collar is formed from a shape memory alloy and is arranged to reduce its inner diameter upon application of heat

Methodology Applied

Scientific EffectShape memory alloy: Shape Memory Alloy

Implementation Method 2

the collar is arranged to reduce its inner diameter upon application of heat

Methodology Applied

Scientific EffectThermal contraction: Thermal Contraction

Implementation Method 3

when exposed to a patient's blood, be brought to body temperature (i.e. about 37° C.) and thus expand

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS12285326B2Tips stent graft and kit

Publication Date: 2025.04.29 ANGIOMED GMBH & CO MEDIZINTECHNIK KG

AI summary

The present invention relates to a TIPS stent graft, comprising a tubular component having a lumen extending therethrough, the tubular component comprising a balloon expandable central section and a first and a second self-expanding section, the first and the second self-expanding section sandwiching the central section, the lumen extending through the first, central, and second sections, the stent graft being capable of selectively constricting the central section.