Pressure-Unloading LVAD With Pulsatile Flow for Native Ventricular Recovery
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Solution Overview
Problem
Clinically available left ventricular assist devices (LVADs) cause profound ventricular unloading, leading to depressed native left ventricular function and reduced myocardial recovery potential, with continuous-flow devices showing a threefold decrease in recovery rate compared to pulsatile alternatives.
Innovation Solution
A novel implantable counterpulsation LVAD with a rigid housing and elastomeric membrane design that provides ventricular unloading while preserving left ventricular systolic activity and pulsatility, eliminating the need for heart-lung bypass and reducing trauma to native heart tissue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If clinically available LVADs are used to provide ventricular unloading, then cardiac output is improved, but native left ventricular function is depressed
Solution Approach 1:
The patent employs pulsatile flow delivery instead of continuous flow, creating periodic action that mimics natural cardiac cycles. The pump delivers blood in discrete pulses that correspond to cardiac systole and diastole, thereby maintaining native ventricular pulsatility and function while providing adequate cardiac output support.
Solution Approach 2:
The patent changes the flow delivery parameter from continuous to pulsatile, and adjusts pump timing and duration parameters to synchronize with native cardiac cycles. This allows the device to provide sufficient cardiac output while preserving native ventricular function through parameter optimization.
2Productivity
If continuous-flow LVADs are used, then cardiac output is maintained, but myocardial recovery rate decreases threefold
Solution Approach 1:
The patent uses pulsatile flow delivery with periodic cycles that allow intervals between pump activations. These intervals enable native myocardium to recover by maintaining some level of autonomous contraction and reducing continuous mechanical stress, thereby accelerating myocardial recovery while maintaining adequate cardiac output.
Solution Approach 2:
The patent makes the pump operation dynamic by adjusting pulse frequency, duration, and intensity based on patient needs and recovery progress. This dynamic adjustment allows optimization of both cardiac output support and myocardial recovery conditions over time.
3Productivity
If profound ventricular unloading is achieved, then cardiac output is improved, but pulsatility is lost
Solution Approach 1:
The patent deliberately introduces periodic action through pulsatile pump operation to restore and maintain flow pulsatility. The pump delivers blood in rhythmic pulses that create pressure and flow variations in the arterial system, thereby preserving the pulsatile character of blood flow while providing sufficient cardiac output.
Solution Approach 2:
The patent employs feedback mechanisms to monitor native ventricular function and adjust pump parameters accordingly. This feedback control ensures that pulsatility is maintained at optimal levels while providing adequate cardiac output, preventing both excessive unloading and insufficient support.
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 device achieves partial left ventricular pressure unloading, promotes favorable hemodynamic conditions, enhances native left ventricular function, and supports myocardial recovery by maintaining pulsatile flow, with a simpler implantation process and reduced risk of complications.
Implementation Method 1
a movable elastomeric membrane into an air sub-chamber and a blood sub-chamber
Implementation Method 2
an air sub-chamber which is connectible through a drive line to an external pneumatic source
Data Source
AI summary
An implantable pump includes a rigid housing with an oblate spheroid shape and having an inner chamber divided by a movable elastomeric membrane into a gas sub-chamber which is connectible through a drive line to an external pneumatic source, and a blood sub-chamber which is connectible through a graft assembly to an anatomical heart. The housing includes a blood port opening oriented at an angle and at the upper apex of the housing and connected to the blood sub-chamber, and a gas port opening to the gas sub-chamber that is situated at a lower apex of the housing. The pump is provided with a drive line that includes a gas conduit and a heart sensor, the drive line connectible to a drive system that is capable of delivering gas flow through the drive line gas conduit in response to signals driven by the heart sensor.