A new current-based control model of the combined cardiovascular and Rotary Left Ventricular Assist Device

Faragallah, George; Wang, Yu; Divo, Eduardo; Simaan, Marwan A.

doi:10.1109/acc.2011.5990641

Cited by 12 publications

(10 citation statements)

References 16 publications

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“…Pulsatile pumps generate pulsatile blood flow close to the native heart in a beat-like fashion, whereas rotary pumps generate a continuous blood flow [8]. The rotary pump-based LVAD has more advantages over the pulsatile pumps in terms of size, efficiency, durability, noise, and weight [9]. However, an important issue with a rotary LVAD is the optimal control of pump speed, which limits its extensive use.…”

Section: Introductionmentioning

confidence: 99%

Stochastic Modeling and Dynamic Analysis of the Cardiovascular System with Rotary Left Ventricular Assist Devices

Son

2019

Mathematical Problems in Engineering

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The left ventricular assist device (LVAD) has been used for end-stage heart failure patients as a therapeutic option. The aortic valve plays a critical role in heart failure and its treatment with LVAD. The cardiovascular-LVAD model is often used to investigate the physiological demands required by patients and predict the hemodynamic of the native heart supported with a LVAD. As a "bridge to recovery" treatment, it is important to maintain appropriate and active dynamics of the aortic valve and the cardiac output of the native heart, which requires that the LVAD pump must be adjusted so that a proper balance between the blood contributed through the aortic valve and the pump is maintained. In this paper, we investigate how the pump power of the LVAD pump can affect the dynamic behaviors of the aortic valve for different levels of activity and different severities of heart failure. Our objective is to identify a critical value of the pump power (i.e., breakpoint) to ensure that the LVAD pump does not take over the pumping function in the cardiovascular-pump system and share the ejected blood with left ventricle to help the heart to recover. In addition, hemodynamic often involves variability due to patients' heterogeneity and the stochastic nature of cardiovascular system. The variability poses significant challenges to understand dynamic behaviors of the aortic valve and cardiac output. A generalized polynomial chaos (gPC) expansion is used in this work to develop a stochastic cardiovascular-pump model for efficient uncertainty propagation, from which it is possible to rapidly calculate the variance in the aortic valve opening duration and the cardiac output in the presence of variability. The simulation results show that the gPC-based cardiovascular-pump model is a reliable platform that can provide useful information to understand the effect of LVAD pump on the hemodynamic of the heart.

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Section: Introductionmentioning

confidence: 99%

Stochastic Modeling and Dynamic Analysis of the Cardiovascular System with Rotary Left Ventricular Assist Devices

Son

2019

Mathematical Problems in Engineering

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“…In this paper, we will perform all simulations using the well-established non-linear time-varying cardiovascular-LVAD model which was developed in [15]. An electric circuit representation of this model is shown in Fig.…”

Section: A the Cardiovascular-lvad Modelmentioning

confidence: 99%

“…The various parameters and matrices in the model A(t), p(t), r(x), and b are explained in [15] and P E (t) is the pump power which is the control variable in the model. Details on the model and model validation can be found in [15] and [16], respectively.…”

Section: A the Cardiovascular-lvad Modelmentioning

confidence: 99%

Detection of aortic valve dynamics in bridge-to-recovery feedback control of the Left Ventricular Assist Device

Wang

Faragallah

Simaan

2014

2014 European Control Conference (ECC)

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Aortic valve dynamics -which implies continuous opening and closing of the aortic valve in each cardiac cycle during the feedback control of the rotary Left Ventricular Assist Devices (LVAD) support -has important clinical implications for patients with mild congestive heart failure. When the LVAD is implanted in such patients as a bridge-torecovery device, permanent closure of the aortic valve must be avoided by maintaining proper control on the power delivered to the device. In this paper, a new aortic valve dynamics detection algorithm based on a Lagrangian Support Vector Machine (LSVM) model is presented. A detection indicator is derived from the systemic vascular flow signal in the circulatory system using a nonlinear mathematical model of the combined cardiovascular-LVAD system and forms the input to the LSVM classifier. The LSVM classifier is trained and tested to classify the aortic valve dynamics into two states: aortic valve opening and closing (i.e. operating normally) and aortic valve permanently closed. Our results show that the proposed algorithm can detect the aortic valve dynamics effectively in terms of classification accuracy and stability. This classifier will be an integral part in the development of a feedback controller for the LVAD when used on patients as a bridge-to-recovery device. The output of the classifier will be used to adjust the power delivered to the LVAD to ensure that the aortic valve opens and closes normally within each cardiac cycle while at the same time making sure that the physiological demands of the patient are met.

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“…Control algorithms that aim for unloading the LV were elaborated in [23], [24]. Speed regulation algorithms for generating sufficient perfusion and detecting ventricular suction [25], [26] or pulmonary oxygen gas exchange tracking [27] are other goals and, finally, multi-objective variants exist [28].…”

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confidence: 99%

A Personalized Switched Systems Approach for the Optimal Control of Ventricular Assist Devices based on Atrioventricular Plane Displacement

Zeile

Rauwolf

Schmeißer

et al. 2020

Preprint

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Objective: A promising treatment for congestive heart failure is the implementation of a left ventricular assist device (LVAD) that works as a mechanical pump. Modern LVADs work with adjustable constant rotor speed and provide therefore continuous blood flow; however, recently undertaken efforts try to mimic pulsatile blood flow by oscillating the pump speed. This work proposes an algorithmic framework to construct and evaluate optimal pump speed policies. Methods: We use a model that captures the atrioventricular plane displacement, which is a physiological indicator for heart failure. We employ mathematical optimization to adapt this model to patient specific data and to find optimal pump speed policies with respect to ventricular unloading and aortic valve opening. To this end, we reformulate the cardiovascular dynamics into a switched system and thereby reduce nonlinearities. We consider system switches that stem from varying the constant pump speed and that are state dependent such as valve opening or closing. Results: As a proof of concept study, we personalize the model to a selected patient with respect to ventricular pressure. The model fitting results in a root-mean-square deviation of about 6 mmHg. Optimized constant and piecewise constant rotor speed profiles improve the default initialized solution by 31% and 68% respectively. Conclusion: These in silico findings demonstrate the potential of personalized hemodynamical optimization for the LVAD therapy. Significance: LVADs and their optimal configuration are active research fields. Mathematical optimization enhances our understanding of how LVADs should provide pulsatility.

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A new current-based control model of the combined cardiovascular and Rotary Left Ventricular Assist Device

Cited by 12 publications

References 16 publications

Stochastic Modeling and Dynamic Analysis of the Cardiovascular System with Rotary Left Ventricular Assist Devices

Stochastic Modeling and Dynamic Analysis of the Cardiovascular System with Rotary Left Ventricular Assist Devices

Detection of aortic valve dynamics in bridge-to-recovery feedback control of the Left Ventricular Assist Device

A Personalized Switched Systems Approach for the Optimal Control of Ventricular Assist Devices based on Atrioventricular Plane Displacement

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