Numerical Optimal Control of Turbo Dynamic Ventricular Assist Devices

Abstract

Abstract:The current paper presents a methodology for the derivation of optimal operating strategies for turbo dynamic ventricular assist devices (tVADs). In current clinical practice, tVADs are typically operated at a constant rotational speed, resulting in a blood flow with a low pulsatility. Recent research in the field has aimed at optimizing the interaction between the tVAD and the cardiovascular system by using predefined periodic speed profiles. In the current paper, we avoid the limitation of using predefined profiles by formulating an optimal-control problem based on a mathematical model of the cardiovascular system and the tVAD. The optimal-control problem is solved numerically, leading to cycle-synchronized speed profiles, which are optimal with respect to an arbitrary objective. Here, an adjustable trade-off between the maximization of the flow through the aortic valve and the minimization of the left-ventricular stroke work is chosen. The optimal solutions perform better than constant-speed or sinusoidal-speed profiles for all cases studied. The analysis of optimized solutions provides insight into the optimized Bioengineering 2014, 1 23 interaction between the tVAD and the cardiovascular system. The numerical approach to the optimization of this interaction represents a powerful tool with applications in research related to tVAD control. Furthermore, patient-specific, optimized VAD actuation strategies can potentially be derived from this approach.

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

“…This effect is more pronounced in the scenarios with continuous and pwc pump speed, which can be categorized as counterpulsative policies and thus facilitate the aortic pressure to oscillate less. Our finding that a counterpulsative pumping strategy minimizes the given objective function is in accordance with [39], where the same objective function was applied.…”

“…[38] investigated the use of LVADs for preload manipulation maneuvers in animal trials. We build on [39], where the continuous pump speed profile is found with an optimal control algorithm based on a lumped cardiovascular system model and compared with both a constant and a sinusoidalspeed profile. In contrast, we do only numerical simulation and no verification with a mock circulation system.…”

“…Another fundamental difference of our approach to [39] and all other model based approaches lies in the used model: Instead of applying a time-varying elastance function to represent the pressure-volume (PV) relationship in heart chambers, we base our model on the contribution of the longitudinal atrioventricular plane displacement (AVPD) to ventricular pumping, which is novel in the LVAD context. It has been established that the atrioventricular (AV) plane behaves as a piston unit by moving back and forth in the baseapex direction, creating reciprocal volume changes between atria and ventricles [40].…”

Benefits of object-oriented models and ModeliChart: modern tools and methods for the interdisciplinary research on smart biomedical technology

“…Nevertheless, optimal control allows for the realization of clinically motivated goals. Examples which use optimal control in combination with the technically assisted cardiovascular systems can be found in [5,11]. A popular extension of optimal control is the concept of a model-based predictive controller (MPC).…”

Sensorless cardiac phase detection for synchronized control of ventricular assist devices using nonlinear kernel regression model

“…Although a ''constant speed mode'', which makes the rotational speed of the pump constant, is most commonly used in clinical situations, several studies have reported a benefit of pulsatile control synchronizing with the patient's heartbeat [1][2][3][4], which is the so-called heartbeat synchronization method. For instance, Ando et al revealed in [2] that a ''counter pulse drive mode'', which makes the rotational speed to slow down in the patient's systolic phase, can enhance myocardial perfusion.…”