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

Gregory, Shaun D., Schummy, Emma, Pearcy, Mark, Pauls, Jo P., Tansley, Geoff, Fraser, John F. and Timms, Daniel (2014) A compliant, banded outflow cannula for decreased afterload sensitivity of rotary right ventricular assist devices. Artificial Organs, 39 2: 102-109. doi:10.1111/aor.12338


Author Gregory, Shaun D.
Schummy, Emma
Pearcy, Mark
Pauls, Jo P.
Tansley, Geoff
Fraser, John F.
Timms, Daniel
Title A compliant, banded outflow cannula for decreased afterload sensitivity of rotary right ventricular assist devices
Journal name Artificial Organs   Check publisher's open access policy
ISSN 0160-564X
1525-1594
Publication date 2014-07-09
Year available 2014
Sub-type Article (original research)
DOI 10.1111/aor.12338
Open Access Status
Volume 39
Issue 2
Start page 102
End page 109
Total pages 8
Place of publication Hoboken, NJ, United States
Publisher Wiley-Blackwell Publishing
Collection year 2015
Language eng
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, 4.5mm 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 3mm 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.
Keyword Compliant cannula
Suction event
Physiological control
Ventricular assist device
Afterload sensitivity
Heart failure
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes Published online ahead of print 09 July 2014.

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2015 Collection
School of Medicine Publications
 
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