Evaluation of Physiological Control Systems for Rotary Left Ventricular Assist Devices: An In-Vitro Study

Rotary left ventricular assist devices (LVADs) show weaker response to preload and greater response to afterload than the native heart. This may lead to ventricular suction or pulmonary congestion, which can be deleterious to the patient’s recovery. A physiological control system which optimizes res...

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Bibliographic Details
Published in:Annals of biomedical engineering 2016-08, Vol.44 (8), p.2377-2387
Main Authors: Pauls, Jo P., Stevens, Michael C., Bartnikowski, Nicole, Fraser, John F., Gregory, Shaun D., Tansley, Geoff
Format: Article
Language:English
Subjects:
Biochemistry
Biological and Medical Physics
Biomedical and Life Sciences
Biomedical Engineering and Bioengineering
Biomedicine
Biophysics
Blood Flow Velocity
Classical Mechanics
Congestion
Constants
Control systems
Controllers
Female
Heart-Assist Devices
Humans
Male
Medical materials
Models, Cardiovascular
Pumps
Tubes
Vascular Resistance
Ventricular assist devices
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Summary:Rotary left ventricular assist devices (LVADs) show weaker response to preload and greater response to afterload than the native heart. This may lead to ventricular suction or pulmonary congestion, which can be deleterious to the patient’s recovery. A physiological control system which optimizes responsiveness of LVADs may reduce adverse events. This study compared eight physiological control systems for LVAD support against constant speed mode. Pulmonary (PVR) and systemic (SVR) vascular resistance changes, a passive postural change and exercise were simulated in a mock circulation loop to evaluate the controller’s ability to prevent suction and congestion and to increase exercise capacity. Three active and one passive control systems prevented ventricular suction at high PVR (500 dyne s cm −5 ) and low SVR (600 dyne s cm −5 ) by decreasing LVAD speed (by 200–515 rpm) and by increasing LVAD inflow cannula resistance (up to 1000 dyne s cm −5 ) respectively. These controllers increased LVAD preload sensitivity (to 0.196–2.415 L min −1  mmHg −1 ) compared to the other control systems and constant speed mode (0.039–0.069 L min −1  mmHg −1 ). The same three active controllers increased pump speed (600–800 rpm) and thus LVAD flow by 4.5 L min −1 during exercise which increased exercise capacity. Physiological control systems that prevent adverse events and/or increase exercise capacity may help improve LVAD patient conditions.
ISSN:0090-6964
1573-9686
DOI:10.1007/s10439-016-1552-3