title: Evaluation of Physiological Control Systems for Rotary Left Ventricular Assist Devices: An In-Vitro Study.
abstract: 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.
authors.affiliation: School of Engineering, Griffith University, Southport, QLD, Australia. jo.philipp.pauls@gmail.com.|Innovative Cardiovascular Engineering and Technology Laboratory, Critical Care Research Group, The Prince Charles Hospital, Brisbane, QLD, Australia. jo.philipp.pauls@gmail.com.
authors.forename: Jo P
authors.initials: JP
authors.lastname: Pauls
authors.affiliation: Innovative Cardiovascular Engineering and Technology Laboratory, Critical Care Research Group, The Prince Charles Hospital, Brisbane, QLD, Australia.|Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, Australia.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Stevens
authors.affiliation: Innovative Cardiovascular Engineering and Technology Laboratory, Critical Care Research Group, The Prince Charles Hospital, Brisbane, QLD, Australia.|Science and Engineering Faculty, Queensland University of Technology, Brisbane, QLD, Australia.
authors.forename: Nicole
authors.initials: N
authors.lastname: Bartnikowski
authors.affiliation: Innovative Cardiovascular Engineering and Technology Laboratory, Critical Care Research Group, The Prince Charles Hospital, Brisbane, QLD, Australia.|School of Medicine, University of Queensland, Brisbane, QLD, Australia.
authors.forename: John F
authors.initials: JF
authors.lastname: Fraser
authors.affiliation: Innovative Cardiovascular Engineering and Technology Laboratory, Critical Care Research Group, The Prince Charles Hospital, Brisbane, QLD, Australia.|School of Medicine, University of Queensland, Brisbane, QLD, Australia.
authors.forename: Shaun D
authors.initials: SD
authors.lastname: Gregory
authors.affiliation: School of Engineering, Griffith University, Southport, QLD, Australia.|Innovative Cardiovascular Engineering and Technology Laboratory, Critical Care Research Group, The Prince Charles Hospital, Brisbane, QLD, Australia.
authors.forename: Geoff
authors.initials: G
authors.lastname: Tansley
mesh_terms: D001783:Blood Flow Velocity; D005260:Female; D006353:Heart-Assist Devices; D006801:Humans; D008297:Male; D008955:Models, Cardiovascular; D014655:Vascular Resistance
keywords: Active control; Left ventricular assist devices; Passive control; Physiological control; Ventricular suction prevention