Preservation of Native Aortic Valve Flow and Full Hemodynamic Support with the TORVAD Using a Computational Model of the Cardiovascular System

Gohean, Jeffrey R.; George, Mitchell J.; Chang, Kay Won; Larson, Erik R.; Pate, Thomas D.; Kurusz, Mark; Longoria, Raul G.; Smalling, Richard W.

doi:10.1097/mat.0000000000000190

Cited by 13 publications

(9 citation statements)

References 39 publications

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“…The inputs to the model are patient size and HF severity, for which the stroke volume and synchronous operation of the TORVAD can be optimized. This model has been previously used to determine the stroke volume and synchronous operation timing for an adult in end-stage HF (30 mL with an early diastolic synchronous counterpulse) (18). For the purposes of this design, the model has been adapted for pediatric HF by changing model parameters (e.g., systemic volume, vascular resistance, heart rate, left ventricular size and contraction (25–28)), allowing for prediction of the level of support and pump stroke volume that would be needed for children with BSAs between 0.6 and 1.5 m 2 .…”

Section: Design Resultsmentioning

confidence: 99%

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Scaling the Low-Shear Pulsatile TORVAD for Pediatric Heart Failure

et al. 2017

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This article provides an overview of the design challenges associated with scaling the low-shear pulsatile TORVAD ventricular assist device (VAD) for treating pediatric heart failure. A cardiovascular system model was used to determine that a 15 ml stroke volume device with a maximum flow rate of 4 L/min can provide full support to pediatric patients with body surface areas between 0.6 to 1.5 m2. Low shear stress in the blood is preserved as the device is scaled down and remains at least two orders of magnitude less than continuous flow VADs. A new magnetic linkage coupling the rotor and piston has been optimized using a finite element model (FEM) resulting in increased heat transfer to the blood while reducing the overall size of TORVAD. Motor FEM has also been used to reduce motor size and improve motor efficiency and heat transfer. FEM analysis predicts no more than 1°C temperature rise on any blood or tissue contacting surface of the device. The iterative computational approach established provides a methodology for developing a TORVAD platform technology with various device sizes for supporting the circulation of infants to adults.

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Section: Design Resultsmentioning

confidence: 99%

“…The primary synchronous operation mode of the TORVAD is an early diastolic counterpulse (18). By operating the pump in this mode, it briefly ceases to pump blood in systole, allowing the ventricle to eject normally through the aortic valve.…”

Section: Introductionmentioning

confidence: 99%

Scaling the Low-Shear Pulsatile TORVAD for Pediatric Heart Failure

et al. 2017

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“…In a lumped parameter model, a TORVAD with a 30-mL stroke volume ejecting with an early diastolic counterpulse provides comparable systemic support to the HeartMate II (Abbott Inc, Chicago, IL, USA) by taking advantage of synchronous pulsatility with preserved pulse pressure. 46 This pump also showed significantly less blood trauma and markedly lower shear stress than current CF LVADs. We are now developing an advanced ventricular assist device, which is able to generate greater levels of pulsatility and possessing a shut-off feature with the additional ability to modulate the axial position of a rotor by pressure differences in the inlet and outlet.…”

Section: Generating Pfmentioning

confidence: 90%

“…The pump performs blood aspiration and ejection by cyclically actuating a piston around a toroidal pumping chamber via magnetic coupling to a motor while maintaining a second piston in a stationary position to occlude blood flow between the inlet and outlet ports. In a lumped parameter model, a TORVAD with a 30‐mL stroke volume ejecting with an early diastolic counterpulse provides comparable systemic support to the HeartMate II (Abbott Inc, Chicago, IL, USA) by taking advantage of synchronous pulsatility with preserved pulse pressure . This pump also showed significantly less blood trauma and markedly lower shear stress than current CF LVADs.…”

Section: New Durable Mcs Devices Generating Pfmentioning

confidence: 99%

Acute and chronic effects of continuous‐flow support and pulsatile‐flow support

2019

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“…[7], [25] - [27]. Puede comprobarse el desarrollo y perfeccionamiento de muy buenos modelos, pero que pueden ser utilizados bajo muy pocas situaciones.…”

Section: Discussionunclassified

Simulación del Corazón Izquierdo para Aplicaciones en Docencia e Investigación

Cervino

2018

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Un modelo es una descripción lógica de cómo un sistema funciona o cómo se comportan sus componentes. Las herramientas de la modelización dinámica facilitan mucho la construcción de los modelos. El objetivo de este artículo es mostrar el desarrollo y los resultados del funcionamiento de un modelo interactivo de la fisiología del sistema cardiocirculatorio para el uso de estudiantes y otros interesados en la fisiología cardiovascular. El sistema de simulación está compuesto por un modelo simple de cuatro componentes, y simula las siguientes variables y parámetros: a) variaciones del volumen aurícula izquierda (AI) y ventrículo izquierdo (VI); b) variaciones presión en AI, VI y aorta (Ao); c) flujo a través de válvula mitral (VM) y válvula aórtica (VAo), y d) reproduce el "efecto Windkessel" en Ao. Se utilizó el entorno de modelización Extend el cual provee una estructura integrada para la construcción de modelos de simulación y el desarrollo de nuevas herramientas de simulación. El corazón derecho y la circulación pulmonar no son considerados. Los resultados de este modelo simulan las características generales del corazón izquierdo y de la circulación arterial, considerando distintas situaciones fisiológicas y patológicas. AbstractLeft heart simulation for applications in teaching and scientific research. A model is a logical description of how a system works or how their components behave. The tools of the dynamic modeling facilitate the construction of the models. The aim of this article is to show the development and results of the operation of an interactive model of the cardiocirculatory system physiology for the use of students and others interested in cardiovascular physiology. The model used is a simple model of four components, and simulates the following variables and parameters: a) volume variations of left atrial (LA) and left ventricle (LV); b) pressure variations in LA, LV and aorta (Ao); c) the flow across mitral (MV) and aortic valve (AoV), and d) imitates the "Windkessel effect" in Ao. The modeling environment "Extend" was used, which provides an integrated structure for the simulation models construction and the development of new simulations tools. The right heart and the pulmonary circulation are not considered. The model's results simulate the general characteristics of the left heart and of the arterial circulation, considering different physiological and pathological situations.

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Preservation of Native Aortic Valve Flow and Full Hemodynamic Support with the TORVAD Using a Computational Model of the Cardiovascular System

Cited by 13 publications

References 39 publications

Scaling the Low-Shear Pulsatile TORVAD for Pediatric Heart Failure

Scaling the Low-Shear Pulsatile TORVAD for Pediatric Heart Failure

Acute and chronic effects of continuous‐flow support and pulsatile‐flow support

Simulación del Corazón Izquierdo para Aplicaciones en Docencia e Investigación

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