A compliant, banded outflow cannula for decreased afterload sensitivity of rotary right ventricular assist devices

Gregory, Shaun, Schummy, Emma, Pearcy, Mark, Pauls, Jo, Tansley, Geoff, Fraser, John, & Timms, Daniel (2015) A compliant, banded outflow cannula for decreased afterload sensitivity of rotary right ventricular assist devices. Artificial Organs: replacement, recovery, and regeneration, 39(2), pp. 102-109.

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Abstract

Biventricular support with dual rotary ventricular assist devices (VADs) has been implemented clinically with restriction of the right VAD (RVAD) outflow cannula to artificially increase afterload and, therefore, operate within recommended design speed ranges. However, the low preload and high afterload sensitivity of these devices increase the susceptibility of suction events. Active control systems are prone to sensor drift or inaccurate inferred (sensor-less) data, therefore an alternative solution may be of benefit. This study presents the in vitro evaluation of a compliant outflow cannula designed to passively decrease the afterload sensitivity of rotary RVADs and minimize left-sided suction events. A one-way fluid-structure interaction model was initially used to produce a design with suitable flow dynamics and radial deformation. The resultant geometry was cast with different initial cross-sectional restrictions and concentrations of a softening diluent before evaluation in a mock circulation loop. Pulmonary vascular resistance (PVR) was increased from 50 dyne s/cm5 until left-sided suction events occurred with each compliant cannula and a rigid, 4.5 mm diameter outflow cannula for comparison. Early suction events (PVR ∼ 300 dyne s/cm5) were observed with the rigid outflow cannula. Addition of the compliant section with an initial 3 mm diameter restriction and 10% diluent expanded the outflow restriction as PVR increased, thus increasing RVAD flow rate and preventing left-sided suction events at PVR levels beyond 1000 dyne s/cm5. Therefore, the compliant, restricted outflow cannula provided a passive control system to assist in the prevention of suction events with rotary biventricular support while maintaining pump speeds within normal ranges of operation.

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4 citations in Web of Science®

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ID Code: 88708
Item Type: Journal Article
Refereed: Yes
Keywords: Compliant cannula;Suction event;Physiological control;Ventricular assist device;Afterload sensitivity;Heart failure
DOI: 10.1111/aor.12338
ISSN: 0160-564X
Divisions: Current > Schools > School of Chemistry, Physics & Mechanical Engineering
Current > QUT Faculties and Divisions > Science & Engineering Faculty
Copyright Owner: Copyright 2014 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.
Deposited On: 02 Nov 2015 00:46
Last Modified: 02 Nov 2015 00:46

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