Left atrial assist device function at various heart rates using a mock circulation loop

2020 ◽  
pp. 039139882097750
Author(s):  
Yuichiro Kado ◽  
Anthony R Polakowski ◽  
Barry D Kuban ◽  
David J Horvath ◽  
Takuma Miyamoto ◽  
...  
Keyword(s):  
Heart Failure ◽  
Left Atrial ◽  
Diastolic Heart Failure ◽  
New Left ◽  
Aortic Pressure ◽  
Normal Heart ◽  
Assist Device ◽  
Heart Rates ◽  
Mock Circulation

We are developing a new left atrial assist device (LAAD) for patients who have heart failure with preserved ejection fraction (HFpEF). This study aimed to assess the hemodynamic effects of the LAAD under both normal heart conditions and various diastolic heart failure (DHF) conditions using a mock circulatory loop. A continuous-flow pump that simulates LAAD, was placed between the left atrial (LA) reservoir and a pneumatic ventricle that simulated a native left ventricle on a pulsatile mock loop. Normal heart (NH) and mild, moderate, and severe DHF conditions were simulated by adjusting the diastolic drive pressures of the pneumatic ventricle. With the LAAD running at 3200 rpm, data were collected at 60, 80, and 120 bpm of the pneumatic ventricle. Cardiac output (CO), mean aortic pressure (AoP), and mean LA pressure (LAP) were compared to evaluate the LAAD performance. With LAAD support, the CO and AoP rose to a sufficient level at all heart rates and DHF conditions (CO; 3.4–3.8 L/min, AoP; 90–105 mm Hg). Each difference in the CO and the AoP among various heart rates was minuscule compared with non-pump support. The LAP decreased from 21–23 to 17–19 mm Hg in all DHF conditions (difference not significant). Furthermore, hemodynamic parameters improved for all DHF conditions, independent of heart rate. The LAAD can provide adequate flow to maintain the circulation status at various heart rates in an in vitro mock circulatory loop.

Abstract 16365: A New Left Atrial Assist Device for Heart Failure With Preserved Ejection Fraction: In Vitro Test

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Kiyotaka FUKAMACHI ◽  
Barry D Kuban ◽  
Christine Flick ◽  
Jamshid Karimov ◽  
David Horvath ◽  
...  
Keyword(s):  
Heart Failure ◽  
Aortic Valve ◽  
Ejection Fraction ◽  
Left Atrial ◽  
In Vitro Test ◽  
Preserved Ejection Fraction ◽  
Normal Heart ◽  
Assist Device ◽  
Heart Condition

Introduction: The effective treatment for patients with heart failure with preserved ejection fraction is not yet established. We previously reported the concept of the left atrial assist device (LAAD) that pumps blood from the left atrium to the left ventricle to treat diastolic heart failure (DHF). We have now developed the first working prototype of the LAAD that can be implanted at the mitral valve level (Fig. 1). The purpose of the study was to demonstrate that the LAAD can reduce left atrial pressure (LAP) and increase cardiac output (CO) while maintaining arterial pulsatility and normal aortic valve function in the in vitro DHF model. Methods: The LAAD was tested at three pump speeds (3,600, 4,400 and 5,200 rpm) on a pulsatile mock loop with a pneumatic pump that simulated the normal function of the native ventricle, as well as mild, moderate, and severe DHF conditions, by adjusting the diastolic drive pressure to limit diastolic filling of the ventricle. Results: Without the LAAD, CO and aortic pressure (AoP) decreased dramatically: from 3.9 L/min and 102 mm Hg at normal heart condition to 1.0 L/min and 33 mm Hg at severe DHF, respectively (Fig. 2A, 2B). With LAAD support, both CO and AoP recovered to normal heart values at 4,200 rpm and surpassed normal heart values at 5,200 rpm (Fig. 2A, 2B). With LAAD support, LAP recovered to that of the normal heart condition at 5,200 rpm (Fig. 2C). The pulsatility was maintained (Fig. 2D), as all the CO went through the aortic valve. Conclusions: These initial in vitro results support our hypothesis that use of the LAAD increases CO and AoP and decreases LAP under DHF conditions, while maintaining arterial pulsatility and full function of the aortic valve.

Use of a Virtual Mock Loop model to evaluate a new left ventricular assist device for transapical insertion

2020 ◽  
Vol 43 (10) ◽  
pp. 677-683
Author(s):  
Yuichiro Kado ◽  
William A Smith ◽  
Takuma Miyamoto ◽  
Joseph Adams ◽  
Anthony R Polakowski ◽  
...  
Keyword(s):  
Heart Failure ◽  
Left Ventricular Assist Device ◽  
Ventricular Assist Device ◽  
Diastolic Heart Failure ◽  
Aortic Pressure ◽  
Left Ventricular ◽  
Loop System ◽  
Assist Device ◽  
Ventricular Assist ◽  
Left Ventricular Assist

We are developing a novel type of miniaturized left ventricular assist device that is configured for transapical insertion. The aim of this study was to assess the performance and function of a new pump by using a Virtual Mock Loop system for device characterization and mapping. The results, such as pressure-flow performance curves, from pump testing in a physical mock circulatory loop were used to analyze its function as a left ventricular assist device. The Virtual Mock Loop system was programmed to mimic the normal heart condition, systolic heart failure, diastolic heart failure, and both systolic and diastolic heart failure, and to provide hemodynamic pressure values before and after the activation of several left ventricular assist device pump speeds (12,000, 14,000, and 16,000 r/min). With pump support, systemic flow and mean aortic pressure increased, and mean left atrial pressure and pulmonary artery pressure decreased for all heart conditions. Regarding high pump-speed support, the systemic flow, aortic pressure, left atrial pressure, and pulmonary artery pressure returned to the level of the normal heart condition. Based on the test results from the Virtual Mock Loop system, the new left ventricular assist device for transapical insertion may be able to ease the symptoms of patients with various types of heart failure. The Virtual Mock Loop system could be helpful to assess pump performance before in vitro bench testing.

Left Atrial Circulatory Assistance in Simulated Diastolic Heart Failure Model: First in Vitro and in Vivo

2022 ◽  
Author(s):  
Chihiro Miyagi ◽  
Kiyotaka Fukamachi ◽  
Barry D. Kuban ◽  
Shengquiang Gao ◽  
Takuma Miyamoto ◽  
...  
Keyword(s):  
Heart Failure ◽  
Left Atrial ◽  
Diastolic Heart Failure ◽  
Failure Model ◽  
Heart Failure Model

Experimental Analysis of Pulsatile Flow Through Elastic Collapsible Tubes: Application to Cardiac Assist Device

1990 ◽  
Vol 112 (1) ◽  
pp. 75-79 ◽  
Author(s):  
O. Lichtenstein ◽  
U. Dinnar
Keyword(s):  
Systemic Circulation ◽  
Aortic Pressure ◽  
Assist Device ◽  
Cardiac Assist ◽  
Cardiac Assist Device ◽  
Non Invasive ◽  
Failing Heart ◽  
In Series ◽  
Vitro Analysis

This study presents a simulated analysis of Phased Compression Cardiac Assist Device (PCCAD) and evaluation of its applicability as a non-invasive temporary assist for a failing heart. The new technique is based on the chest pump mechanism for blood flow augmentation during external massage by phased compression of the abdominal and thoracic cavities. A semi-closed hydraulic system to simulate the systemic circulation was constructed; the system includes a left ventricle which functions according to the Starling principle and a pneumatic system which controls the pressures applied to the thoracic and abdominal cavities, in complete synchronization with the beating normal or failing heart. The possibility of manipulating the three pumps in series (venous, heart, and arterial) has been checked, and the principal parameters which effect the efficiency of the PCCAD were evaluated. This in-vitro analysis shows the high potential of a non-invasive temporary cardiac assist device. It points to the necessary measures one has to take in order to achieve good synchronization and to interfere externally with the augmentation of cardiac output or with the augmentation of root aortic pressure.

A Systemic Mock Circulation for In-Vitro Testing of a Pneumatically Operated Left Ventricular Assist Device

2014 ◽  
Vol 47 (3) ◽  
pp. 8409-8414 ◽  
Author(s):  
A. Karabegovic ◽  
M. Hinteregger ◽  
C. Janeczek ◽  
W. Reichenfelser ◽  
V. Soragnese ◽  
...  
Keyword(s):  
Left Ventricular Assist Device ◽  
Ventricular Assist Device ◽  
Left Ventricular ◽  
In Vitro Testing ◽  
Assist Device ◽  
Ventricular Assist ◽  
Mock Circulation ◽  
Left Ventricular Assist

Role of Diastole in Left Ventricular Function, II: Diagnosis and Treatment

2004 ◽  
Vol 13 (6) ◽  
pp. 453-466 ◽  
Author(s):  
Shannan K. Hamlin ◽  
Penelope S. Villars ◽  
Joseph T. Kanusky ◽  
Andrew D. Shaw
Keyword(s):  
Heart Failure ◽  
Diastolic Dysfunction ◽  
Left Atrial ◽  
Diastolic Heart Failure ◽  
Systolic Heart Failure ◽  
Clinical Signs ◽  
Left Ventricular ◽  
Exercise Intolerance ◽  
Radiographic Findings ◽  
Ventricular Compliance

Left ventricular diastolic dysfunction plays an important role in congestive heart failure. Although once thought to be lower, the mortality of diastolic heart failure may be as high as that of systolic heart failure. Diastolic heart failure is a clinical syndrome characterized by signs and symptoms of heart failure with preserved ejection fraction (0.50) and abnormal diastolic function. One of the earliest indications of diastolic heart failure is exercise intolerance followed by fatigue and, possibly, chest pain. Other clinical signs may include distended neck veins, atrial arrhythmias, and the presence of third and fourth heart sounds. Diastolic dysfunction is difficult to differentiate from systolic dysfunction on the basis of history, physical examination, and electrocardiographic and chest radiographic findings. Therefore, objective diagnostic testing with cardiac catheterization, Doppler echocardiography, and possibly measurement of serum levels of B-type natriuretic peptide is often required. Three stages of diastolic dysfunction are recognized. Stage I is characterized by reduced left ventricular filling in early diastole with normal left ventricular and left atrial pressures and normal compliance. Stage II or pseudonormalization is characterized by a normal Doppler echocardiographic transmitral flow pattern because of an opposing increase in left atrial pressures. This normalization pattern is a concern because marked diastolic dysfunction can easily be missed. Stage III, the final, most severe stage, is characterized by severe restrictive diastolic filling with a marked decrease in left ventricular compliance. Pharmacological therapy is tailored to the cause and type of diastolic dysfunction.

scholarly journals Stimulation of left-atrial protein-synthesis rates by increased left-atrial filling pressures in the perfused working rat heart in vitro

1983 ◽  
Vol 216 (3) ◽  
pp. 537-542 ◽  
Author(s):  
D M Smith ◽  
P H Sugden
Keyword(s):  
Protein Synthesis ◽  
Internal Control ◽  
Rat Heart ◽  
Left Atrial ◽  
Aortic Pressure ◽  
Filling Pressure ◽  
Right Atrial ◽  
The Right ◽  
Working Rat Heart

We investigated the effect of an increase in the left-atrial filling pressure on the rate of left-atrial protein synthesis in the left-side-perfused working rat heart preparation of Taegtmeyer, Hems & Krebs [(1980) Biochem. J. 186, 701-711]. An increase in filling pressure (preload) at a constant aortic pressure (afterload) increased both the intra-atrial pressure and the atrial stroke volume. The aortic pressure (afterload) was held constant. An increase in filling pressure from 5 to 20 cmH2O at an aortic pressure of 70 cmH2O, or an increase in filling pressure of 7.5 to 20 cmH2O at an aortic pressure of 100 cmH2O, significantly stimulated the rates of left-atrial protein synthesis by 30-40%. The stimulation was observed when the rates of protein synthesis were expressed relative to either protein or RNA content. Since perfusate entering the right atrium from the coronary circulation left that atrium passively, the rate of protein synthesis in this compartment can be used as an internal control. Rates of right-atrial protein synthesis were similar to those in the left atria exposed to the lower filling pressures and were unaffected by the increases in left-atrial filling pressure. We suggest that the acute effects of increased left-atrial filling pressure on protein synthesis in that compartment may be important in the development of left-atrial hypertrophy. This condition is seen in patients who have raised pulmonary venous pressures in, for example, mitral stenosis.

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