Stretchable tubular device and use thereof as a counterpulsation device
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Solution Overview
Problem
Current cardiac assist devices, such as ventricular assist devices (VADs) and aortic counterpulsation devices, face limitations including high risk of hemolysis and thrombosis, lack of pulsatile flow, mechanical complexity, and uncontrollable delays in activation, making them unsuitable for long-term, lightweight, and efficient heart support.
Innovation Solution
A stretchable tubular device with electroactive polymer layers that mimics the natural properties of an artery, using inherent visco-elasticity and controlled voltage application to modulate its diameter and assist heart function by storing and releasing energy passively, without mechanical parts, to provide pulsatile flow and reduce heart effort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rotary pumps are used in VADs, then mechanical reliability and fast response are improved, but high shear causes hemolysis and thrombosis
Solution Approach 1:
The patent replaces the rotary mechanical pump system with an electroactive polymer-based artificial muscle system. The electroactive polymer layers (including dielectric layers and conductive layers) expand and contract in response to electrical voltage, generating pulsatile flow without rotating mechanical components. This substitution eliminates high shear forces while maintaining mechanical reliability and fast electrical response.
2Productivity
If rotary pumps are used in VADs, then continuous flow is achieved, but pulsatile flow is lost
Solution Approach 1:
The patent implements periodic action by applying alternating voltage cycles to the electroactive polymer layers. The layers expand during voltage application (systole phase) and contract during voltage release (diastole phase), creating natural pulsatile flow patterns. This periodic electrical stimulation mimics physiological heart cycles and restores the beneficial pulsatile flow characteristics.
3Device complexity
If pneumatic drivelines are used in counterpulsation devices, then simplicity of implant is achieved, but uncontrollable delays and huge external systems are required
Solution Approach 1:
The patent replaces the pneumatic driveline system with direct electrical actuation of electroactive polymer layers. Electrical signals provide immediate and precisely controllable activation without the time delays inherent in pneumatic systems. The electrical fields directly induce polymer expansion and contraction, enabling real-time control and eliminating the need for complex external pneumatic infrastructure.
4Object-affected harmful factors
If stretchable tubular device with electroactive polymer is used, then pulsatile flow and natural arterial properties are mimicked, but device complexity increases
Solution Approach 1:
The patent employs thin flexible electroactive polymer films stacked in alternating dielectric and conductive layers. These thin-film structures provide the necessary compliance and stretchability to mimic natural arterial properties while maintaining structural integrity. The flexible nature of the polymer layers allows the device to expand and contract dynamically, preserving physiological pulsatile flow patterns without rigid mechanical components.
Solution Approach 2:
The device utilizes composite material construction with multiple electroactive polymer layers (dielectric layers and conductive layers) stacked together. This composite structure combines the benefits of electrical actuation with the mechanical properties of flexible polymers, achieving both pulsatile flow generation and natural arterial compliance in a single integrated system.
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 mimics natural arterial properties, reducing heart effort by up to 5% during systole and enhancing diastolic blood pressure, while eliminating mechanical complications and delays, offering a lightweight, efficient, and controllable cardiac assistance.
Implementation Method 1
The stretchable tubular device comprises one or several layers of electroactive polymers, stacked in a tubular arrangement
Implementation Method 2
The device is produced from a visco-elastic material and mimics the natural properties of an artery, using inherent visco-elasticity to store and release energy passively
Implementation Method 3
When the diameter of the tubular device is extended larger than its native diameter, then the inherent visco-elasticity exerts a natural force tending to recover its native diameter
Data Source
Figure 1a~1c
Figure 2
Figure 3a~3b
AI summary
The present invention is related to a stretchable tubular device (1) comprising at least one layer (Lx) of a stretchable polymer, a power supply (2) and a set of electrodes (3a, 3b) connected to said power supply (2). The power supply can supply at least a first level of voltage (V1) to the electrodes so as to modify the natural force (F0) of the stretchable layers to a modified force (F1). The present invention also covers a process for manufacturing such a tubular device and its use as a medical implant.