Pulsatile LVAD With Tubular Linear Motor for Cardiac Synchronization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Continuous-flow LVADs cause significant side effects such as altered arterial baroreceptors, increased cardiovascular risk factors, aortic valve issues, gastrointestinal bleeding, and blood pressure measurement challenges due to lack of pulsatility, which are not effectively addressed by existing technologies.
Innovation Solution
A left ventricular assist device (LVAD) system with a tubular linear motor, magnetic piston, and spring mechanism that provides pulsatile blood flow synchronized with cardiac cycles, using a cardiac sensor and control circuitry to manage energy consumption and mimic natural heart function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If continuous-flow LVADs are used to provide constant blood ejection, then blood flow to systemic circulation is maintained, but arterial baroreceptors are altered and cardiovascular risk factors increase due to lack of pulsatility
Solution Approach 1:
The patent applies periodic action by implementing a pulsatile flow mechanism that mimics natural cardiac cycles. The LVAD delivers blood in discrete pulses rather than continuous flow, with each pulse corresponding to a simulated systolic event. This periodic delivery pattern restores pulsatility to the systemic circulation, allowing baroreceptors to function normally while maintaining adequate blood flow to organs.
2Productivity
If continuous-flow LVADs are used to maintain blood circulation, then cardiac output is sustained, but aortic valve strain increases causing fusion and regurgitation
Solution Approach 1:
The pulsatile flow mechanism creates periodic opening and closing forces on the aortic valve. During each pulsatile ejection phase, the valve experiences natural opening forces from increased flow, and during diastolic phases, closing forces are applied. This periodic mechanical stimulation prevents the valve from remaining in a constant state of strain, thereby reducing the risk of fusion and regurgitation while maintaining cardiac output.
3Productivity
If continuous-flow LVADs are used to provide constant blood flow, then systemic circulation is maintained, but gastrointestinal bleeding occurs due to lack of pulsatility and enhanced proteolysis
Solution Approach 1:
The pulsatile flow delivers periodic high-velocity blood flow pulses to the gastrointestinal circulation. These pulsatile flows create periodic shear stresses that inhibit platelet activation and reduce proteolytic activity in the gut wall. The intermittent nature of the flow allows tissue perfusion to occur during diastolic phases, preventing the continuous ischemic conditions that lead to gastrointestinal bleeding in continuous-flow systems.
4Productivity
If continuous-flow LVADs are used to sustain blood pressure, then flow to organs is maintained, but blood pressure control and measurement become challenging
Solution Approach 1:
The pulsatile flow generates periodic pressure waves that propagate through the arterial system, creating distinct systolic and diastolic pressure phases. These pressure variations enable the use of standard sphygmomanometric measurement techniques and allow clinicians to assess blood pressure control in a manner familiar to practitioners. The periodic pressure changes also provide feedback for adjusting pump parameters to optimize organ perfusion while maintaining appropriate blood pressure levels.
5Object-affected harmful factors
If pulsatile flow is implemented to mimic natural heart function, then baroreceptor function and blood pressure control are improved, but device complexity and power consumption increase
Solution Approach 1:
The patent replaces complex mechanical valve mechanisms with a magnetically-driven valveless pump design. The pulsatile flow is achieved through controlled variation of motor speed and direction, eliminating the need for mechanical moving parts such as valves, pistons, or diaphragms. This substitution reduces device complexity, improves reliability, and simplifies the overall pump architecture while maintaining the beneficial pulsatile flow pattern for baroreceptor function and blood pressure control.
6Object-affected harmful factors
If pulsatile flow is implemented to reduce cardiovascular side effects, then organ function is supported, but energy consumption and battery demand increase
Solution Approach 1:
The patent employs dynamic speed control of the motor to optimize energy consumption. The motor speed is varied continuously throughout the cardiac cycle, with higher speeds during systolic ejection phases and lower speeds during diastolic phases. This dynamic adjustment allows the pump to deliver pulsatile flow with reduced peak power demands compared to maintaining constant high speed, thereby extending battery life while preserving the cardiovascular benefits of pulsatility.
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
Reduces peak power consumption and mimics natural heart function, providing pulsatile blood flow that alleviates side effects and supports critical organ function, while reducing the demand on power sources like batteries.
Implementation Method 1
The stator is configured to magnetically drive the magnetic piston with reciprocating motion
Implementation Method 2
The pump further comprises a spring, which is arranged to store energy during upstream motion of the magnetic piston and release the stored energy during the downstream motion of the magnetic piston
Data Source
AI summary
An implantable LVAD is provided that includes a pump shaped so as to define a pump chamber. The pump includes a tubular linear motor, which includes a magnetic piston, which includes a reciprocating one-way valve configured to allow downstream blood flow and inhibit upstream blood flow; and a stator, which is configured to magnetically drive the magnetic piston with reciprocating motion, so as to pump blood downstream during downstream motion of the magnetic piston while the reciprocating one-way valve is closed. The pump further includes a spring, which is arranged to store energy during upstream motion of the magnetic piston and release the stored energy during the downstream motion of the magnetic piston. Control circuitry is configured to activate the tubular linear motor to provide pulsatile flow synchronized with cardiac cycles. Other configurations are also described.