Rotary Valve Pulsatile Flow Control for Constant-Flow Heart Pumps
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Solution Overview
Problem
Current medical devices, such as Ventricular Assist Devices (VADs) and Total Artificial Hearts, that use constant flow pumps fail to replicate the natural pulsatile blood flow of the heart, leading to complications like hemolysis, gastrointestinal bleeding, and aortic insufficiency, and are complex, costly, and have reduced durability.
Innovation Solution
The development of a rotary valve system capable of delivering pulsatile flow at various frequencies, which can be controlled to mimic natural heart rhythms, by using a rotatable valve member with apertures that can rotate continuously or periodically, and can be actuated electromagnetically or mechanically, to be integrated with constant-flow pumps, reducing complexity and cost while enhancing durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If constant flow pumps are used in medical devices, then the device structure is simple and cost is reduced, but the device fails to replicate natural pulsatile blood flow causing complications
Solution Approach 1:
The rotary valve member rotates periodically to alternately align and misalign apertures with the conduit, creating pulsatile flow cycles. Each rotation cycle produces a sequence of flow acceleration and deceleration phases that replicate natural heart rhythm, transforming constant pump flow into physiologically appropriate pulsatile flow patterns.
Solution Approach 2:
The rotary valve member is designed to rotate dynamically between different angular positions, transitioning from aligned to misaligned states. This dynamic motion allows the valve to modulate flow continuously throughout the rotation cycle, creating the acceleration and deceleration phases characteristic of natural pulsatile blood flow while maintaining mechanical simplicity.
2Reliability
If pulsatile flow is produced using traditional mechanisms, then natural heart rhythm is replicated, but the device becomes complex, costly, and less durable
Solution Approach 1:
The patent replaces complex traditional pulsatile pump mechanisms with a simple rotary valve member that modulates flow from a constant-flow pump. Instead of using multiple moving parts, valves, and actuators typical of pulsatile systems, the invention uses a single rotating component with apertures that passively creates pulsatile flow patterns through its rotation, significantly reducing mechanical complexity.
Solution Approach 2:
The rotary valve member serves multiple functions simultaneously: it acts as a flow modulator, a rhythm generator, and a flow direction controller. By integrating these functions into a single rotating component rather than requiring separate mechanisms for each function, the device achieves complex pulsatile flow control with minimal structural complexity.
3Reliability
If rotary valve with apertures is used, then pulsatile flow is produced, but flow control precision is reduced
Solution Approach 1:
The rotary valve member is designed with specific geometric parameters including aperture size, aperture shape, number of apertures, and rotation speed. By optimizing these parameters, the system achieves precise control over pulsatile flow characteristics such as flow rate, pulse frequency, and waveform shape. The aperture geometry is specifically configured to regulate flow acceleration and deceleration rates, ensuring precise flow control while maintaining pulsatile flow production.
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 rotary valve system effectively produces mathematically accurate pulsatile flow, reducing strain on the right side of the heart, improving aortic valve function, and extending the longevity of medical devices, making them more affordable and reliable alternatives for heart failure treatment.
Implementation Method 1
a rotatable valve member configured to be operatively connected to and rotate relative to a fluid conduit. The rotatable valve member includes at least one aperture. The rotatable valve member is capable of being positioned in a plurality of positions relative to the conduit
Implementation Method 2
The rotary valve can be actuated electromagnetically or mechanically
Data Source
AI summary
A medical device includes a constant-flow pump configured to pump a fluid through a fluid conduit and a rotary valve fluidically connected to the pump. The rotary valve includes at least one rotatable valve member configured to be operatively connected to and rotate relative to the fluid conduit. The rotatable valve member includes at least one aperture. The rotatable valve member is capable of being positioned in a plurality of positions relative to the conduit. The position of the at least one first aperture of the rotatable valve member controls fluid flow through the rotary valve, and thereby through the conduit.