Experimental investigation of right‐left flow balance concepts for a total artificial heart

Diedrich, Mario; Hildebrand, Stephan; Lommel, Moritz K.; Finocchiaro, Thomas; Cuenca, Elena; Ben, Heiko De; Schmitz‐Rode, Thomas; Steinseifer, Ulrich; Jansen, Sebastian

doi:10.1111/aor.13830

Cited by 6 publications

(12 citation statements)

References 12 publications

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“…As reported in the two studies with patients with TAH, the difference between left and right flow can vary from 0 to 1.4 L/min 18,19 . In accordance with the previous investigation on different flow balance concepts, the interval from 0 to 1.5 L/min is selected as the target range to assess the controllability of the flow balance 28 . For each scenario, it is verified whether the target area is fully met and how many combinations of HR and RD result in the performance within the targeted area.…”

Section: Methodsmentioning

confidence: 96%

“…In a previous study, several different concepts of right‐left flow balance regulation have been investigated 26 . It was shown that a combination of a reduced right stroke volume together with an active control of the diastole duration resulted in an adequate flow balance 28 . Compared with the left pump chamber, with an effective stroke volume of 45 mL, the stroke volume of the right pump chamber was reduced by design.…”

Section: Methodsmentioning

confidence: 99%

“…26 It was shown that a combination of a reduced right stroke volume together with an active control of the diastole duration resulted in an adequate flow balance. 28 Compared with the left pump chamber, with an effective stroke volume of 45 mL, the stroke volume of the right pump chamber was reduced by design. The reduction of the effective right stroke volume by 10% was verified in a static measurement prior to the study.…”

Section: The Reinheart Tahmentioning

confidence: 99%

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Controlling the flow balance: In vitro characterization of a pulsatile total artificial heart in preload and afterload sensitivity

et al. 2021

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The objective of this study is to identify the preload and afterload sensitivity of the ReinHeart TAH 2.0. For adequate left-right flow balance, the concept of a reduced right stroke volume (by about 10%) and active adaption of the right diastole duration are evaluated concerning the controllability of the flow balance. This study used an active mock circulation loop to test a wide range of preload and afterload conditions.Preload sensitivity was tested at atrial pressures (APs) between 4 and 20 mm Hg. Left afterload was varied in a range of 60-140 mm Hg mean aortic pressure (MAP), right afterload was simulated between 15 and 40 mm Hg. Four scenarios were developed to verify that the flow difference fully covers the defined target range of 0-1.5 L/min. Although a positive correlation between inlet pressure and flow is identified for the right pump chamber, the left pump chamber already fills completely at an inlet pressure of 8-10 mm Hg. With increasing afterload, both the left and right flow decrease.A positive flow balance (left flow exceeds right flow) is achieved over the full range of tested afterloads. At high APs, the flow difference is limited to a maximum of 0.7 L/min. The controllability of flow balance was successfully evaluated in four scenarios, revealing that a positive flow difference can be achieved over the full range of MAPs. Under physiological test conditions, the linear relationship between flow and heart rate was confirmed, ensuring good controllability of the TAH.

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Section: Methodsmentioning

confidence: 96%

Section: Methodsmentioning

confidence: 99%

Section: The Reinheart Tahmentioning

confidence: 99%

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Controlling the flow balance: In vitro characterization of a pulsatile total artificial heart in preload and afterload sensitivity

et al. 2021

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“…In addition to this value, we also studied 60 and 175 cycles/min. In the ReinHeart TAH, the left–right circulation flow disbalance due to the pulmonary shunt is mitigated by adjusting the ratio of left and right diastole duration RD 15 . For each of the three HR values, we set the RD to 40, 45, and 50%.…”

Section: Methodsmentioning

confidence: 99%

“…The ReinHeart TAH has been previously explained in detail. 15 Briefly, it is an electrically driven TAH system with an actuator in which a piston with its alternating left and right moves empties the left and right chambers (Figure 1) into the systemic and pulmonary circulation, respectively. The reference position of the piston in time is preset in accordance with the HR.…”

Section: Pulsatile Reinheart Tah and Force Profilementioning

confidence: 99%

Detection of physiological control inputs preload and afterload from intrinsic pump parameters in total artificial heart

et al. 2022

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Background In the total artificial heart (TAH), the inputs to the physiological control unit, preload, and afterload, are detected from intrinsic pump parameters (e.g., motor current). Within this study, their detection techniques are developed, and their reliability in pre‐ and afterload prediction is mapped for a broad range of cardiovascular system states. Methods We used ReinHeart TAH which is a fully implantable TAH with a plunger coil drive that is alternately emptying the left and right chambers. From the coil currents we first derived a force generated by the piston with respect to its position and then analyzed its pattern to detect (1) preload—chamber filling, found as piston position at begin ejection and (2) afterload—mean outflow pressures, determined as linearly calibrated average piston force during ejection. TAH is then integrated into a mock loop circulation (MLC) which is set to 135 different steady operating points varying in chamber filling (0%–100%, five steps), mean outflow pressures (system circulation: 60–90–120 mm Hg, pulmonary circulation: 15–30‐45 mm Hg), and heart cycle duration (171–600 ms in seven non‐equidistant steps). The detected preload and afterload are compared to MLC set values, and the errors are mapped. Results Respectively for the left and right chambers, the preload was detectable in 134 and 118 operating points and the mean error was ±3% and ±2%. The afterload was detectable in 135 and 87 operating points and the mean error was 37% and 30% respectively for left and right circulation. The operational points that are further away from homeostatic equilibrium values generally yielded larger errors. The largest errors were observed for right circulation at long cycle duration, low afterload, and low filling. Conclusions The study yields reliable preload estimation in a broad range of physiological states, particularly for left circulation. Detection of afterload needs further improvements. The study revealed a need for piston movement optimization within the ReinHeart TAH during the early phase of systole.

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The ongoing quest for the first total artificial heart as destination therapy

et al. 2022

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Experimental investigation of right‐left flow balance concepts for a total artificial heart

Abstract: This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Cited by 6 publications

References 12 publications

Controlling the flow balance: In vitro characterization of a pulsatile total artificial heart in preload and afterload sensitivity

Controlling the flow balance: In vitro characterization of a pulsatile total artificial heart in preload and afterload sensitivity

Detection of physiological control inputs preload and afterload from intrinsic pump parameters in total artificial heart

The ongoing quest for the first total artificial heart as destination therapy

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