Oval Renal Vein Stent Valve for Pressure-Responsive Flow Balancing
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Solution Overview
Problem
Patients with congestive heart failure (CHF) and chronic kidney disease (CKD) experience impaired renal function due to decreased renal pressure gradient and elevated renal venous pressure, leading to reduced glomerular filtration rate (GFR) and potential end-stage renal failure.
Innovation Solution
Implantable devices with a stent frame and a valve mechanism are introduced into renal veins to modulate blood flow, featuring a stent frame with a substantially oval cross-sectional shape and a valve with moveable leaflets that restrict flow in response to elevated pressure, thereby increasing the renal pressure gradient and improving GFR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a valve mechanism is introduced to restrict blood flow in response to elevated pressure, then the renal pressure gradient is increased and GFR is improved, but the device complexity increases
Solution Approach 1:
The valve mechanism is designed to automatically respond to elevated renal venous pressure without requiring external control systems. The valve opens or closes based on pressure differential, allowing the device to self-regulate blood flow and protect renal function without adding complex control electronics or external actuation systems.
Solution Approach 2:
The valve component utilizes flexible membrane structures that can deform in response to pressure changes. This flexible membrane approach allows the valve to open and close passively based on pressure differential, avoiding the need for rigid mechanical components, motors, or complex actuation mechanisms, thereby maintaining device simplicity while achieving reliable flow restriction.
2Reliability
If an implantable device with valve is introduced into renal veins, then blood flow is actively managed to improve GFR, but the manufacturing complexity increases
Solution Approach 1:
The stent and valve components are designed as an integrated assembly that can be manufactured and deployed together. The valve mechanism is incorporated into the stent structure itself, allowing for streamlined manufacturing processes and reducing the number of separate components that need to be assembled, thereby improving ease of manufacture while maintaining the therapeutic function.
Solution Approach 2:
The valve characteristics (opening pressure, closing pressure, flow restriction level) are optimized during the manufacturing process by controlling material properties and geometric parameters. This allows the device to be manufactured with predetermined performance characteristics that ensure reliable kidney function protection without requiring complex post-manufacturing adjustments or calibration procedures.
3Stress or pressure
If the valve restricts flow through the aperture, then the renal pressure gradient increases, but the blood flow volume decreases
Solution Approach 1:
The valve is designed to dynamically adjust its opening degree based on the instantaneous pressure differential across it. When renal venous pressure is moderately elevated, the valve remains partially open to maintain adequate blood flow volume. When pressure exceeds a threshold, the valve closes to protect the kidney. This dynamic response allows the device to preserve blood flow volume during normal conditions while protecting against pressure-induced damage.
Solution Approach 2:
The valve provides partial flow restriction rather than complete occlusion, allowing sufficient blood flow to maintain kidney perfusion while creating enough pressure gradient to protect against venous congestion. The valve opening area is sized to provide the optimal balance between maintaining flow volume and generating protective pressure gradient under varying physiological conditions.
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 enhance kidney function by increasing the renal pressure gradient and reducing blood volume retention, actively managing blood flow to improve GFR and reduce venous congestion.
Implementation Method 1
the valve is configured to cause the at least one leaflet to move in the radial direction to reduce a cross-sectional area of the aperture and restrict flow through the valve in response to elevated pressure within the blood vessel
Implementation Method 2
modulate blood flow through and/or into one or more blood vessels associated with the renal arteries and/or renal veins... increase the renal pressure gradient
Data Source
AI summary
Systems and methods are described for modulating blood flow through a blood vessel. The systems may include one or more implantable devices including a stent frame positionable within the blood vessel, the stent frame having a substantially oval cross-sectional shape, and a valve defining an inflow end and an outflow end. The inflow end may be coupled to the stent frame and the outflow end defining an aperture and the valve may include at least one leaflet at the outflow end. The at least one leaflet may be positionable to overlay at least a portion of the aperture and configured to move in a radial direction that is perpendicular to a central axis of the stent frame.