In-silico evaluation of left ventricular unloading under varying speed continuous flow left ventricular assist device support

Bozkurt, Selim; Bozkurt, Surhan

doi:10.1016/j.bbe.2017.03.003

Cited by 19 publications

(13 citation statements)

References 53 publications

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“…The single fiber contraction models allow simulating the fiber tension in a heart chamber, in addition to the blood pressure and volume [7]. The single fiber contraction models have also been used to simulate physiological and clinical scenarios such as the influence of intra-myocardial pressure on the coronary arterial blood flow rate [8], simulation of fetal heart rate variability [9] or evaluation of rotary blood pump support [10] etc. Although these models are driven by the fiber contraction and provide more information about the cardiac physiology, they also remain insufficient to simulate different mechanisms occurring at each level of cardiac contraction and do not provide information about clinical indicators such as heart chamber dimensions for the physiological cases.…”

Section: Introductionmentioning

confidence: 99%

Mathematical modeling of cardiac function to evaluate clinical cases in adults and children

Bozkurt

2019

PLoS ONE

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Time-varying elastance models can simulate only the pressure and volume signals in the heart chambers while the diagnosis of clinical cases and evaluation of different treatment techniques require more information. In this study, an extended model utilizing the geometric dimensions of the heart chambers was developed to describe the cardiac function. The new cardiac model was evaluated by simulating a healthy and dilated cardiomyopathy (DCM) condition for adults and children. The left ventricular ejection fraction, end-diastolic volume, end-diastolic diameter and diastolic sphericity index were 53.60%, 125 mL, 5.08 cm and 1.82 in the healthy adult cardiovascular system model and 23.70%, 173 mL, 6.60 cm and 1.40 in the DCM adult cardiovascular system model. In the healthy child cardiovascular system model, the left ventricular ejection fraction, end-diastolic volume, end-diastolic diameter and diastolic sphericity index were 59.70%, 92 mL, 4.10 cm and 2.26 respectively and 30.70%, 125 mL, 4.94 cm and 1.87 in the DCM child cardiovascular system model. The developed cardiovascular system model simulates the hemodynamic variables and clinical diagnostic indicators within the physiological range for healthy and DCM conditions proving the feasibility of this new model to evaluate clinical cases in adults and children.

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Section: Introductionmentioning

confidence: 99%

Mathematical modeling of cardiac function to evaluate clinical cases in adults and children

Bozkurt

2019

PLoS ONE

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“…Varying speed CF-LVAD support have implications on the cardiac function and blood flow in the circulatory system. Left ventricular unloading is improved under counter-pulsating CF-LVAD support [27]. Aortic valve opening duration and coronary perfusion are also increased under counter-pulsating CF-LVAD support [12], [28].…”

Section: Discussionmentioning

confidence: 98%

“…Severe mitral insufficiency may increase the right ventricular afterload as well [26]. It has already been shown that changing the CF-LVAD operating speed continuously over a cardiac cycle may improve the unloading of the left ventricle [27]. Unloading of the left ventricle with mitral valve insufficiency under varying speed CF-LVAD support will also depend on the pump speed variation.…”

Section: Discussionmentioning

confidence: 99%

Pressure, Flow Rate and Operating Speed Characteristics of a Continuous Flow Left Ventricular Assist Device During Varying Speed Support

Bozkurt

2020

IEEE Access

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Hydraulic performance of Continuous Flow Left Ventricular Assist Devices depends on their pressure head and flow rate relations. Hydraulic characteristics of these devices are expressed by pressure head and flow rate loops in a pulsatile environment as they are implanted between left ventricular apex and aorta. Nonetheless, constant speed Continuous Flow Left Ventricular Assist Device support causes complications due to altered blood flow in the patients' body. Therefore, beat-to-beat varying speed Continuous Flow Left Ventricular Assist Device support algorithms have been proposed to operate these devices in synchronized co-pulsating or counter-pulsating modes which can generate more physiological blood flow in the circulatory system. However, the effect of speed variation on the pressure head and flow rate loops remains unclear during varying speed Continuous Flow Left Ventricular Assist Device support. In this study, pressure head, flow rate and operating speed relations during co-pulsating and counterpulsating pump support in a Continuous Flow Left Ventricular Assist Device were analyzed utilizing numerical simulations. Simulation results show that pressure head-flow rate-operating speed loops can express Continuous Flow Left Ventricular Assist Device characteristics better during varying speed heart pump support. Moreover, pump flow rate-operating speed and pressure head-operating speed diagrams show the dynamic behavior of a heart pump, including also the speed. Therefore, understanding the relationship between speed, flow rate and the pressure difference across a pump may help to develop novel beat-to-beat operating modes to improve Continuous Flow Left Ventricular Assist Device support.

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“…e hemodynamic model was based on the research of Korakianitis and Shi et al [20]. Compared with some simplified models [21,22], the model shows more details for the simulation of the human blood circulation system, which includes systemic circulation, pulmonary circulation, the left and right ventricles, and atria. e systemic circulation and pulmonary circulation circuits include arteries, veins, arterioles, capillaries, and aortic sinus and pulmonary sinus, respectively.…”

Section: Establishment Of Coupling Model Of Hemodynamics and Cfdmentioning

confidence: 99%

Shear Stress and Hemolysis Analysis of Blood Pump under Constant and Pulsation Speed Based on a Multiscale Coupling Model

Wang

Tan

2020

Mathematical Problems in Engineering

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Current researches show that the constant speed mode adopted by the existing commercial blood pump may cause damage to the body. The way to solve this problem is to produce pulsating flow by changing the speed of the blood pump’s impeller. But at present, the flow field of the blood pump is not clear, when it changes speed, and the coupling between blood pump and body has not been considered in the simulation of the flow field. A multiscale coupling model combining hemodynamics (0D) and Computational Fluid Dynamics (3D) was established in this paper to solve the problem, and a speed change curve consistent with the ventricular motion was selected. The hemodynamics, shear stress, and hemolysis changes of 6000 rpm at different amplitude (2000, 3000, and 4000 rpm) were simulated, analyzed, and compared with the constant speed (7000 rpm). The results show that the pressure difference obtained by simulation is consistent with the experimental results, and the flow generated by the natural heart still flows through the blood pump, thus changing the working point of the blood pump. When the blood pump works at the changing speed, it could produce more pulsation, and the shear stress and hemolysis in the blood pump increase with the rising of speed and flow. But according to the hemolysis score of a single cardiac cycle, the hemolysis value of the changing speed model at an amplitude of 4000 rpm is only 11.71% higher than that of constant speed at 7000 rpm.

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In-silico evaluation of left ventricular unloading under varying speed continuous flow left ventricular assist device support

Cited by 19 publications

References 53 publications

Mathematical modeling of cardiac function to evaluate clinical cases in adults and children

Mathematical modeling of cardiac function to evaluate clinical cases in adults and children

Pressure, Flow Rate and Operating Speed Characteristics of a Continuous Flow Left Ventricular Assist Device During Varying Speed Support

Shear Stress and Hemolysis Analysis of Blood Pump under Constant and Pulsation Speed Based on a Multiscale Coupling Model

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