Synchrony Relationships between the Left Ventricle and a left Ventricular Assist Device: An Experimental Study in Pigs

Heredero, Angeles; Pérez–Caballero, Ramón; Otero, Javier; Rodríguez–Martínez, Daniel; Quintana‐Villamandos, Begoña; Rodríguez-Bernal, G.; González-Pinto, Ángel; Ruiz-Fernandez, Manuel; Cañizo, Juan F. Del

doi:10.5301/ijao.5000086

Cited by 11 publications

(13 citation statements)

References 14 publications

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“…They found the best ventricular unloading in terms of hydraulic stroke work (SW) during asynchronous operation with the stroke frequency in the same range as the patient's HR. This investigation was further assessed by Heredero et al [14] and Amacher et al [2], who found that under synchronous operation the timing between ventricle and pump systole has a remarkable impact on the unloading of the left ventricle in terms of hydraulic SW. This influence was not investigated in [24].…”

Section: Introductionmentioning

confidence: 97%

High-frequency operation of a pulsatile VAD – a simulation study

Rebholz

Amacher

Petrou

et al. 2017

Biomedical Engineering / Biomedizinische Technik

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Ventricular assist devices (VADs) are mechanical blood pumps that are clinically used to treat severe heart failure. Pulsatile VADs (pVADs) were initially used, but are today in most cases replaced by turbodynamic VADs (tVADs). The major concern with the pVADs is their size, which prohibits full pump body implantation for a majority of patients. A reduction of the necessary stroke volume can be achieved by increasing the stroke frequency, while maintaining the same level of support capability. This reduction in stroke volume in turn offers the possibility to reduce the pump's overall dimensions. We simulated a human cardiovascular system (CVS) supported by a pVAD with three different stroke rates that were equal, two-or threefold the heart rate (HR). The pVAD was additionally synchronized to the HR for better control over the hemodynamics and the ventricular unloading. The simulation results with a HR of 90 bpm showed that a pVAD stroke volume can be reduced by 71%, while maintaining an aortic pulse pressure (PP) of 30 mm Hg, avoiding suction events, reducing the ventricular stroke work (SW) and allowing the aortic valve to open. A reduction by 67% offers the additional possibility to tune the interaction between the pVAD and the CVS. These findings allow a major reduction of the pVAD's body size, while allowing the physician to tune the pVAD according to the patient's needs.

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Section: Introductionmentioning

confidence: 97%

High-frequency operation of a pulsatile VAD – a simulation study

Rebholz

Amacher

Petrou

et al. 2017

Biomedical Engineering / Biomedizinische Technik

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“…This agrees with the previous research, 46 where the authors concluded that when the rotational speed of the CF-LVADs was synchronized to the heart beat, the arterial perfusion was improved. Similarly, Heredero et al 47 reported that the synchronized mode of LVAD operation might satisfy the blood demand. As shown in Figure 9, the eeP exhibits similar pattern, which is consistent with the previous research.…”

Section: Discussionmentioning

confidence: 96%

Pumping Rate Study of a Left Ventricular Assist Device in a Mock Circulatory System

Zhuang

Yang

et al. 2016

ASAIO Journal

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The aim of this work was to investigate the hemodynamic influence of the change of pump rate on the cardiovascular system with consideration of heart rate and the resonant characteristics of the arterial system when a reliable synchronous triggering source is unavailable. Hemodynamic waveforms are recorded at baseline conditions and with the pump rate of left ventricular assist device (LVAD) at 55, 60, 66, and 70 beats per minute for four test conditions in a mock circulatory system. The total input work (TIW) and energy equivalent pressure (EEP) are calculated as metrics for evaluating the hemodynamic performance within different test conditions. Experimental results show that TIW and EEP achieve their maximum values, where the pump rate is equal to the heart rate. In addition, it demonstrates that TIW and EEP are significantly affected by changing pump rate of LVAD, especially when the pump rate is closing to the natural frequency of the arterial system. When a reliable synchronous triggering source is not available for LVAD, it is suggested that selecting a pump rate equal to the resonant frequency of the arterial system could achieve better supporting effects.

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“…Kishimoto [26] et al found that when the rotational speed of the CF-LVADs is synchronized to the heart beat, the arterial perfusion is improved and the risk of aortic insufficiency is reduced. Similarly, Heredero et al [27] reported that the synchronous mode of CF-LVADs operation may be satisfy the blood demand and restore the pulsatility of the aortic pressure. These studies show that the various support modes can significantly change the hemodynamic state of cardiovascular system.…”

Section: Discussionmentioning

confidence: 99%

Hemodynamic effects of various support modes of continuous flow LVADs on the cardiovascular system: A numerical study

Song

Gao

et al. 2014

Med Sci Monit

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BackgroundThe aim of this study was to determine the hemodynamic effects of various support modes of continuous flow left ventricular assist devices (CF-LVADs) on the cardiovascular system using a numerical cardiovascular system model.Material/MethodsThree support modes were selected for controlling the CF-LVAD: constant flow mode, constant speed mode, and constant pressure head mode of CF-LVAD. The CF-LVAD is established between the left ventricular apex and the ascending aorta, and was incorporated into the numerical model. Various parameters were evaluated, including the blood assist index (BAI), the left ventricular external work (LVEW), the energy of blood flow (EBF), pulsatility index (PI), and surplus hemodynamic energy (SHE).ResultsThe results show that the constant flow mode, when compared to the constant speed mode and the constant pressure head mode, increases LVEW by 31% and 14%, and EBF by 21% and 15%, respectively, indicating that this mode achieved the best ventricular unloading among the 3 support modes. As BAI is increased, PI and SHE are gradually decreased, whereas PI of the constant pressure head reaches the maximum value.ConclusionsThe study demonstrates that the continuous flow control mode of the CF-LVAD may achieve the highest ventricular unloading. In contrast, the constant rotational speed mode permits the optimal blood perfusion. Finally, the constant pressure head strategy, permitting optimal pulsatility, should optimize the vascular function.

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Synchrony Relationships between the Left Ventricle and a left Ventricular Assist Device: An Experimental Study in Pigs

Abstract: This study shows that the synchronous mode of LVAD operation is feasible. Moreover, a delay in device contraction until the second half of the cardiac cycle optimizes ventricular unloading and may eventually improve myocardial recovery.

Cited by 11 publications

References 14 publications

High-frequency operation of a pulsatile VAD – a simulation study

High-frequency operation of a pulsatile VAD – a simulation study

Pumping Rate Study of a Left Ventricular Assist Device in a Mock Circulatory System

Hemodynamic effects of various support modes of continuous flow LVADs on the cardiovascular system: A numerical study

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