The influence of rotary blood pump speed modulation on the risk of intraventricular thrombosis

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Liao, S., Wu, E.L., Neidlin, M., Li, Z., Simpson, B. ORCID: 0000-0002-4615-5708 and Gregory, S.D., 2018. The influence of rotary blood pump speed modulation on the risk of intraventricular thrombosis. Artificial Organs, 42 (10), pp. 943-953. ISSN 0160-564X

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Official URL: https://doi.org/10.1111/aor.13330

Abstract

Rotary left ventricular assist devices (LVADs) are commonly operated at a constant speed, attenuating blood flow pulsatility. Speed modulation of rotary LVADs have been demonstrate to improve vascular pulsatility and pump washout. The effect of LV AD speed modulation on intraventricular flow dynamics is not well understood, which may have an influence on thromboembolic events. This study aimed to numerically evaluate intraventricular flow characteristics with a speed modulated LVAD. A severely dilated anatomical left ventricle was supported by a HeartWare HVAD in a three-dimensional multiscale computational fluid dynamics model. Three LVAD operating scenarios were evaluated: constant speed and sinusoidal co- and counter-pulsation. In all operating scenarios, the mean pump speed was set to restore the cardiac output to 5.0 l/min. Co-and counter-pulsation was speed modulated with an amplitude of 750 rpm. The risk of thrombosis was evaluated based on blood residence time, ventricular washout, kinetic energy densities and a pulsatility index map. Blood residence time for co-pulsation was on average 1.8% and 3.7% lower than constant speed and counter-pulsation mode, respectively. After introducing fresh blood to displace pre- existing blood for 10 cardiac cycles, co-pulsation had 1.5% less old blood in comparison to counter- pulsation. Apical energy densities were 84% and 27% higher for co-pulsation in comparison to counter-pulsation and constant speed mode, respectively. Co-pulsation had an increased pulsatility index around the left ventricular outflow tract and mid-ventricle. Improved flow dynamics with co-pulsation was caused by increased E-wave velocities which minimised blood stasis. In the studied scenario and from the perspective of intraventricular flow dynamics, co-pulsation of rotary LVADs could minimise the risk of intraventricular thrombosis.

Item Type:

Journal article

Description:

In special issue: Contributions from the 25th Congress of the International Society for Mechanical Circulatory Support.

Publication Title:

Artificial Organs

Creators:

Liao, S., Wu, E.L., Neidlin, M., Li, Z., Simpson, B. and Gregory, S.D.

Publisher:

Wiley-Blackwell

Date:

October 2018