A Versatile Hybrid Mock Circulation for Hydraulic Investigations of Active and Passive Cardiovascular Implants

Petrou, Anastasios; Granegger, Marcus; Meboldt, Mirko; Daners, Marianne Schmid

doi:10.1097/mat.0000000000000851

Cited by 23 publications

(19 citation statements)

References 29 publications

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“…This loop relied on the inherent compliance of trapped air but is limited in recreating high frequency and physiologic waveforms. 19 Petrou et al 20 reported their versatile hybrid mock circulation loop, which can model three different conditions: a BiVAD, a TAH, and the flow distribution of a total cavopulmonary connection (TCPC) in a Fontan circulation. These authors examined the loop performance of complex active or passive cardiovascular implants, such as TAHs and TCPCs, and found it difficult to validate the numerical models used with clinical observations.…”

Section: Discussionmentioning

confidence: 99%

Development of a circulatory mock loop for biventricular device testing with various heart conditions

et al. 2020

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This study aimed to evaluate a newly designed circulatory mock loop intended to model cardiac and circulatory hemodynamics for mechanical circulatory support device testing. The mock loop was built with dedicated ports suitable for attaching assist devices in various configurations. This biventricular mock loop uses two pneumatic pumps (Abiomed AB5000™, Danvers, MA, USA) driven by a dual-output driver (Thoratec Model 2600, Pleasanton, CA, USA). The drive pressures can be individually modified to simulate a healthy heart and left and/or right heart failure conditions, and variable compliance and fluid volume allow for additional customization. The loop output for a healthy heart was tested at 4.2 L/min with left and right atrial pressures of 1 and 5 mm Hg, respectively; a mean aortic pressure of 93 mm Hg; and pulmonary artery pressure of 17 mm Hg. Under conditions of left heart failure, these values were reduced to 2.1 L/min output, left atrial pressure = 28 mm Hg, right atrial pressure = 3 mm Hg, aortic pressure = 58 mm Hg, and pulmonary artery pressure = 35 mm Hg. Right heart failure resulted in the reverse balance: left atrial pressure = 0 mm Hg, right atrial pressure = 30 mm Hg, aortic pressure = 100 mm Hg, and pulmonary artery pressure = 13 mm Hg with a flow of 3.9 L/min. For biventricular heart failure, flow was decreased to 1.6 L/min, left atrial pressure = 13 mm Hg, right atrial pressure = 13 mm Hg, aortic pressure = 52 mm Hg, and pulmonary artery pressure = 18 mm Hg. This mock loop could become a reliable bench tool to simulate a range of heart failure conditions.

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Section: Discussionmentioning

confidence: 99%

Development of a circulatory mock loop for biventricular device testing with various heart conditions

et al. 2020

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“…C, In vitro setup. The pVAD is connected to the actuation system and two tanks of the hybrid mock circulation (HMC) 25 that dynamically apply the pressure in the pump chamber, the left ventricular (LVP) and aortic (AoP) pressures at the pVAD inlet and outlet, respectively. The pressure is measured at the pump inlet and outlet, providing information regarding left ventricular and aortic pressure.…”

Section: Methodsmentioning

confidence: 99%

“…The in vitro experiments were conducted on a hybrid mock circulation (HMC) system described earlier by Petrou et al 25 On this HMC, the CVS is simulated only numerically and in real time. The computed values were applied via a hydraulic interface to two pressure-controlled reservoirs that represented the left ventricle and the aorta ( Figure 1C), respectively.…”

Section: In Vitro Experimentsmentioning

confidence: 99%

Control of ventricular unloading using an electrocardiogram‐synchronized pulsatile ventricular assist device under high stroke ratios

et al. 2020

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Pulsatile ventricular assist devices (pVADs) yield a blood flow that imitates the pulsatile flow of the heart and, therefore, could diminish the adverse events related to the continuous flow provided by the ventricular assist devices that are commonly used. However, their intrinsic characteristics of larger size and higher weight set a burden to their implantation, that along with the frequent mechanical failures and thrombosis events, reduce the usage of pVADs in the clinical environment. In this study, we investigated the possibility to reduce the pump size by using high pump stroke ratios while maintaining the ability to control the hemodynamics of the cardiovascular system (CVS). In vitro and in vivo experiments were conducted with a custom pVAD implemented on a hybrid mock circulation system and in five sheep, respectively. The actuation of the pVAD was synchronized with the heartbeat. Variations of the pump stroke ratio, time delay between the pump stroke and the heart stroke, as well as duration of the pump systole in respect to the total cardiac cycle duration were used to evaluate the effects of various pump settings on the hemodynamics of the CVS. The results suggest that by varying the operating settings of the pVAD, a pulsatile flow that provides physiological hemodynamic parameters, as well as a control over the hemodynamic parameters, can be achieved. Additionally, by employing high pump stroke ratios, the size of the pVAD can be significantly reduced; however, at those high pump stroke ratios, the effect of the other pump parameters diminishes.

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“…The in vitro tests were conducted on the testbench described earlier by Petrou et al with only the left side being connected to the pVAD. Figure shows the recorded metrics and their respective measurement location.…”

Section: Methodsmentioning

confidence: 99%

Short‐term physiological response to high‐frequency‐actuated pVAD support

et al. 2019

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Ventricular assist devices (VADs) are an established treatment option for heart failure (HF). However, the devices are often plagued by material‐related hemocompatibility issues. In contrast to continuous flow VADs with high shear stresses, pulsatile VADs (pVADs) offer the potential for an endothelial cell coating that promises to prevent many adverse events caused by an insufficient hemocompatibility. However, their size and weight often precludes their intracorporeal implantation. A reduction of the pump body size and weight of the pump could be achieved by an increase in the stroke frequency while maintaining a similar cardiac output. We present a new pVAD system consisting of a pump and an actuator specifically designed for actuation frequencies of up to 240 bpm. In vitro and in vivo results of the short‐term reaction of the cardiovascular system show no significant changes in left ventricular and aortic pressure between actuation frequencies from 60 to 240 bpm. The aortic pulsatility increases when the actuation frequency is raised while the heart rate remains unaffected in vivo. These results lead us to the conclusion that the cardiovascular system tolerates short‐term increases of the pVAD stroke frequencies.

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A Versatile Hybrid Mock Circulation for Hydraulic Investigations of Active and Passive Cardiovascular Implants

Cited by 23 publications

References 29 publications

Development of a circulatory mock loop for biventricular device testing with various heart conditions

Development of a circulatory mock loop for biventricular device testing with various heart conditions

Control of ventricular unloading using an electrocardiogram‐synchronized pulsatile ventricular assist device under high stroke ratios

Short‐term physiological response to high‐frequency‐actuated pVAD support

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