Passive Pump Reducing Ventricular Wall Stress
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Solution Overview
Problem
Heart failure, characterized by the heart's inability to pump enough blood due to weakened pumping action, particularly in the left ventricle, leading to increased pressure and congestion in pulmonary circulation, necessitates a method to assist the heart's ventricle without relying on machinery or circuitry.
Innovation Solution
A passive pump system comprising a noncompliant bag and a compliant balloon, with a conduit allowing fluid to move between them in response to cardiac cycle pressures, positioned within the ventricle and outside the heart, facilitating fluid exchange to reduce ventricular volume during systole and promote reverse remodeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a passive pump system with fluid exchange between bag and balloon is implemented, then ventricular wall stress is reduced, but device complexity increases
Solution Approach 1:
The device divides the fluid containment function into two separate components: a noncompliant bag positioned inside the ventricle and a compliant balloon positioned outside the heart. This segmentation allows each component to perform its specific function optimally while reducing overall system complexity compared to a single integrated device.
Solution Approach 2:
A conduit acts as an intermediary element connecting the intraventricular bag and the extraventricular balloon, enabling passive fluid exchange between them. This intermediary structure facilitates the stress-reduction mechanism without requiring complex active pumping components within the ventricle.
2Productivity
If fluid volume in the ventricle is reduced during systole, then ejection fraction increases, but the device structure becomes more complex
Solution Approach 1:
The device utilizes the periodic pressure changes of the cardiac cycle to drive passive fluid exchange. During systole, increased ventricular pressure forces fluid from the bag into the balloon; during diastole, pressure equalization allows fluid to return. This periodic action achieves ejection fraction improvement without requiring continuous active pumping.
Solution Approach 2:
The heart's own pressure fluctuations during the cardiac cycle serve as the driving force for fluid exchange, eliminating the need for external power sources or complex control systems. The system is self-regulating, using the heart's natural physiology to achieve therapeutic effects.
3Stability of the object's composition
If a noncompliant bag and compliant balloon system is used, then reverse remodeling is facilitated, but manufacturing complexity increases
Solution Approach 1:
The device exploits differences in compliance parameters between the two receptacles. The noncompliant bag maintains stable volume during pressure changes, while the compliant balloon expands and contracts passively. This parameter differentiation enables reverse remodeling through controlled fluid shifts without requiring complex manufacturing processes.
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 system reduces ventricular wall stress, leading to acute and chronic decreases in wall stress, facilitating reverse remodeling of the heart, thereby improving the heart's ability to pump blood effectively and increasing ejection fraction.
Implementation Method 1
a compliant balloon... configured to expand upon transfer of the fluid into the balloon from the bag, and to contract upon passage of at least part of the fluid out of the balloon
Implementation Method 2
The volume of fluid is passable between the bag and the compliant balloon via the conduit passively and responsively to changes in pressure associated with respective stages of the cardiac cycle
Data Source
AI summary
A method for repairing a heart includes identifying a heart of a patient as having a reduced ejection fraction. In response to the identifying, wall stress of a ventricle of the heart is reduced by implanting apparatus that facilitates cyclical moving of fluid that is not blood of the patient into and out of the ventricle of the heart. During ventricular diastole, a volume of the fluid is moved into the ventricle in a manner that produces a corresponding decrease in a total volume of blood that fills the ventricle during diastole. During ventricular systole, the volume of the fluid is moved out of the ventricle in a manner that produces a corresponding decrease in a total volume of the ventricle during isovolumetric contraction of the ventricle. Other embodiments are also described.