Pressure-Responsive Blood Vessel Flow Restrictors for Kidney Perfusion
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Solution Overview
Problem
Chronic kidney disease and heart failure patients experience impaired kidney function due to elevated right atrium pressure, leading to fluid overload and increased hospital admissions, as conventional methods struggle to efficiently manage blood flow and pressure.
Innovation Solution
Implantable flow restrictors for blood vessels that modulate and balance blood flow by occluding or partially occluding vessels in response to pressure changes, using mechanisms like leaflets, springs, and flexible commissures to regulate blood flow and pressure, particularly in the Superior Vena Cava and Inferior Vena Cava, improving kidney perfusion and function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods are used to manage blood flow and pressure, then device simplicity is maintained, but kidney function improvement is insufficient
Solution Approach 1:
The flow restrictor device is divided into multiple functional components: a frame structure, multiple leaflets (first and second leaflets), commissures connecting them, and spring elements. Each component performs a specific function in regulating blood flow and responding to pressure changes, allowing the system to achieve complex physiological control through modular design.
Solution Approach 2:
The device incorporates dynamic elements including movable leaflets that respond to pressure differential, flexible commissures that allow movement between states, and spring elements that provide restoring force. These dynamic components enable the device to automatically adjust blood flow restriction based on real-time pressure conditions without external control.
2Stress or pressure
If leaflets are configured to move toward each other in response to blood pressure increase, then pressure regulation is improved, but device structural complexity increases
Solution Approach 1:
The leaflets are designed to automatically respond to blood pressure changes without external actuation. When pressure differential increases, the pressure gradient itself drives the leaflets to move toward each other, restricting flow. The spring elements provide the restoring force to return leaflets to their original position when pressure normalizes, creating a self-regulating system.
Solution Approach 2:
The device replaces complex electronic or mechanical control systems with a passive mechanical response mechanism. The leaflets and springs utilize fundamental mechanical principles (pressure differential, elastic restoration) to achieve pressure regulation, eliminating the need for sensors, actuators, or power sources.
3Productivity
If flow restrictors are used to reduce right atrium pressure, then kidney filtration is improved, but blood flow restriction may affect overall circulation
Solution Approach 1:
The device dynamically changes the flow restriction parameter based on blood pressure conditions. At normal pressure, the leaflets remain in an open position allowing full blood flow. When pressure increases, the leaflets move to restrict flow, and the degree of restriction is proportional to the pressure increase, creating a responsive regulation mechanism that maintains kidney perfusion while preventing overload.
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 devices effectively reduce right atrium pressure, improve kidney filtration rates, and minimize hospital readmissions by actively managing blood flow and pressure, ensuring sufficient blood flow during exertion while reducing venous pressure at rest, thus enhancing patient quality of life and survival rates.
Implementation Method 1
a first spring positioned between the inner valve and the outer frame... The first spring can be configured to hold the inner valve in a first axial position within the outer frame when the blood pressure within the blood vessel is within the first blood pressure range, and to allow the inner valve to move to a second axial position when the blood pressure within the blood vessel is within a second blood pressure range
Implementation Method 2
The inflow end of each leaflet can be configured to move toward each other in response to a first increase in a blood pressure within the blood vessel
Data Source
AI summary
A flow restrictor for a blood vessel can include a frame positionable within a blood vessel, and a leaflet or flap comprising an inflow end and an outflow end. The inflow end of the leaflet or flap can be configured to move (optionally using a control element) in response to a first increase in a blood pressure within the blood vessel, and in response to the blood pressure being within a first blood pressure range. The flow restrictor can be further configured to be a bi-modal flow restrictor, wherein the leaflet or flap can be configured to collapse or prolapse in response to the blood pressure being within a second blood pressure range. In some cases, the bi-modal flow restrictor can include an inner valve configured to move with respect to the frame in response to the blood pressure being within the second blood pressure range.