Increasing the transmitted flow pulse in a rotary left ventricular assist device

Gaddum, Nicholas Richard, Fraser, John F. and Timms, Daniel Lee (2012) Increasing the transmitted flow pulse in a rotary left ventricular assist device. Artificial Organs, 36 10: 859-867. doi:10.1111/j.1525-1594.2012.01485.x

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Author Gaddum, Nicholas Richard
Fraser, John F.
Timms, Daniel Lee
Total Author Count Override 3
Title Increasing the transmitted flow pulse in a rotary left ventricular assist device
Journal name Artificial Organs   Check publisher's open access policy
ISSN 0160-564X
Publication date 2012-10
Year available 2012
Sub-type Article (original research)
DOI 10.1111/j.1525-1594.2012.01485.x
Volume 36
Issue 10
Start page 859
End page 867
Total pages 9
Place of publication Hoboken, NJ, United States
Publisher Wiley-Blackwell Publishing
Collection year 2013
Language eng
Abstract Long-term rotary left ventricular assist devices (LVADs) are increasingly employed to bridge patients with end-stage heart failure to transplant or as a destination therapy. Significant recent device development has increased patient support times, shifting further development focus toward physiologically sensitive control of the pump operation. Sensorless control of these devices would benefit from increased observability of the ventricular volume/preload to the pump, in order to regulate flow based on preload, imitating the native Frank-Starling flow control. Monitoring the transmitted flow pulse through the pump has been used as a surrogate for preload, although means of maximizing its transmission are not clear. However, it is known that a flat hydraulic performance curve of the rotary pump induces high changes in flow for a given change in pressure head.The aim of this study was to determine geometric pump parameters responsible for increasing this flow pulse transmission and to demonstrate this increase in vitro. The sensitivity of the performance gradient to blade angles, blade heights, blade clearance, and channel areas were studied. Resulting pressure head, flow, and hydraulic efficiency were analyzed with respect to textbook designed procedures. Then pumps with comparably “flat” and “steep” performance curves were used to simulate LVAD support in vitro over a range of pump flow rates to observe the transmitted flow pulsatility. It was found that an outlet blade angle of 90°, inlet blade angle between 25 and 45°, and large throat area generated a “flatter” performance curve. The transmitted flow pulsatility through a pump with a flat performance curve was 68% higher than that of a steep performance curve at a flow rate of 5 L/min. Substantial gains in the observability of LVAD preload/ resident blood volume in the ventricle exist through the careful selection of specific pump geometries.
Keyword Rotary pump design
Left ventricular assist device control
Performance gradient
Transmitted flow pulse
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2013 Collection
School of Medicine Publications
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Citation counts: TR Web of Science Citation Count  Cited 4 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 3 times in Scopus Article | Citations
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Created: Fri, 12 Apr 2013, 18:57:42 EST by System User on behalf of Anaesthesiology and Critical Care - RBWH