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

Song Z, Gu K, Gao B, Wan F, Chang Y, Zeng Y - Med. Sci. Monit. (2014)

Bottom Line: The 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.Finally, the constant pressure head strategy, permitting optimal pulsatility, should optimize the vascular function.

View Article: PubMed Central - PubMed

Affiliation: Department of Cardiac Surgery, Peking University Third Hospital, Beijing, China (mainland).

ABSTRACT

Background: The 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 and methods: Three 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).

Results: The 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.

Conclusions: The 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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The relationship between the control variable of three support mode and the BAI.
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f2-medscimonit-20-733: The relationship between the control variable of three support mode and the BAI.

Mentions: Figure 2 shows the relationship between the control variables of the 3 support modes and the BAI value. In this study, the control variables of 3 support modes, including the pressure head across CF-LVADs, flow rate of CF-LVADs, and the rotational speed of CF-LVADs, were increased to achieve the BAI value increasing from 20% to 90%. For the constant speed mode, the desired rotational speed of CF-LVADs is increased from 5880 RPM to 10 860 RPM. Similarly, the desired pressure head of CF-LVADs in constant pressure head mode is increased from 70 mmHg to 190 mmHg. The pump flow rate in the continuous flow mode increased from 1.9L/min to 10.5L/min.


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

Song Z, Gu K, Gao B, Wan F, Chang Y, Zeng Y - Med. Sci. Monit. (2014)

The relationship between the control variable of three support mode and the BAI.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4020910&req=5

f2-medscimonit-20-733: The relationship between the control variable of three support mode and the BAI.
Mentions: Figure 2 shows the relationship between the control variables of the 3 support modes and the BAI value. In this study, the control variables of 3 support modes, including the pressure head across CF-LVADs, flow rate of CF-LVADs, and the rotational speed of CF-LVADs, were increased to achieve the BAI value increasing from 20% to 90%. For the constant speed mode, the desired rotational speed of CF-LVADs is increased from 5880 RPM to 10 860 RPM. Similarly, the desired pressure head of CF-LVADs in constant pressure head mode is increased from 70 mmHg to 190 mmHg. The pump flow rate in the continuous flow mode increased from 1.9L/min to 10.5L/min.

Bottom Line: The 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.Finally, the constant pressure head strategy, permitting optimal pulsatility, should optimize the vascular function.

View Article: PubMed Central - PubMed

Affiliation: Department of Cardiac Surgery, Peking University Third Hospital, Beijing, China (mainland).

ABSTRACT

Background: The 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 and methods: Three 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).

Results: The 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.

Conclusions: The 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.

Show MeSH