Counterpulsation LVAD Membrane Pump for Partial Ventricular Unloading
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Solution Overview
Problem
Clinically available left ventricular assist devices (LVADs) severely depress native left ventricular function, leading to reduced myocardial recovery and increased fibrosis, while lacking pulsatility, which is crucial for heart recovery.
Innovation Solution
A novel implantable counterpulsation LVAD with a rigid housing and elastomeric membrane design that provides ventricular unloading and maintains pulsatility, allowing for partial left ventricular pressure unloading and promoting native heart function recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If clinically available LVADs are used to provide ventricular unloading, then cardiac support function is improved, but native left ventricular function is depressed and myocardial recovery is reduced
Solution Approach 1:
The device provides partial ventricular unloading rather than complete bypass, maintaining a balance between supporting cardiac function and preserving native ventricular activity. The assist device operates at a level that supplements rather than replaces native heart function, allowing myocardial recovery while providing necessary hemodynamic support.
Solution Approach 2:
The device restores pulsatile flow characteristics to match the natural cardiac cycle, creating periodic action that mimics physiological conditions. This pulsatile operation pattern helps maintain native ventricular function while providing mechanical support, contrasting with continuous-flow designs that cause functional depression.
2Productivity
If continuous-flow LVADs are used to assist the left ventricle, then mechanical support is provided, but pulsatility is lost and myocardial recovery rate decreases
Solution Approach 1:
The device is designed to operate in a pulsatile manner synchronized with the cardiac cycle, restoring periodic flow patterns that are essential for myocardial recovery. The pump delivers blood in discrete pulses that mimic natural heart function, maintaining pulsatility while providing mechanical circulatory support.
Solution Approach 2:
The device changes the flow parameters from continuous to pulsatile by varying flow rate and pressure in synchronization with cardiac cycles. This parameter modification restores physiological flow characteristics while maintaining adequate mechanical support, enabling both productivity and pulsatility to coexist.
3Productivity
If profound ventricular unloading is applied to bypass the left ventricle, then cardiac output is maintained, but native ventricular function becomes ineffective and fibrosis increases
Solution Approach 1:
The device applies partial unloading rather than profound bypass, providing just enough mechanical assistance to maintain cardiac output while preserving sufficient native ventricular work. This partial action approach ensures the heart remains engaged in pumping function, preventing disuse atrophy and fibrosis while meeting hemodynamic demands.
Solution Approach 2:
The system incorporates feedback mechanisms that monitor native ventricular function and adjust support levels accordingly. This feedback control ensures that mechanical assistance is tailored to the patient's actual needs, maintaining cardiac output while allowing native function to recover and preventing over-unloading that would lead to fibrosis.
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 preserves left ventricular systolic activity and pulsatility, enhancing myocardial recovery rates and reducing the need for heart-lung bypass, with a simpler implantation process and lower risk of thrombus formation.
Implementation Method 1
a movable elastomeric membrane into an air 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.