Banding the Right Ventricular Assist Device Outflow Conduit: Is It Really Necessary With Current Devices?

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Author(s)
Lo, Casey
Gregory, Shaun
Stevens, Michael
Murphy, Deirdre
Marasco, Silvana
Griffith University Author(s)
Year published
2015
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Show full item recordAbstract
Implantable left ventricular assist devices (LVADs) have been adapted clinically for right-sided mechanical circulatory support (RVAD). Previous studies on RVAD support have established the benefits of outflow cannula restriction and rotational speed reduction, and recent literature has focused on assessing either the degree of outflow cannula restriction required to simulate left-sided afterload, or the limitation of RVAD rotational speeds. Anecdotally, the utility of outflow cannula restriction has been questioned, with suggestion that banding may be unnecessary and may be replaced simply by varying the outflow conduit ...
View more >Implantable left ventricular assist devices (LVADs) have been adapted clinically for right-sided mechanical circulatory support (RVAD). Previous studies on RVAD support have established the benefits of outflow cannula restriction and rotational speed reduction, and recent literature has focused on assessing either the degree of outflow cannula restriction required to simulate left-sided afterload, or the limitation of RVAD rotational speeds. Anecdotally, the utility of outflow cannula restriction has been questioned, with suggestion that banding may be unnecessary and may be replaced simply by varying the outflow conduit length. Furthermore, many patients have a high pulmonary vascular resistance (PVR) at the time of ventricular assist device (VAD) insertion that reduces with pulmonary vascular bed remodeling. It is therefore important to assess the potential changes in flow through an RVAD as PVR changes. In this in vitro study, we observed the use of dual HeartWare HVAD devices (HeartWare Inc., Framingham, MA, USA) in biventricular support (BiVAD) configuration. We assessed the pumps' ability to maintain hemodynamic stability with and without banding; and with varying outflow cannulae length (20, 40, and 60 cm). Increased length of the outflow conduit was found to produce significantly increased afterload to the device, but this was not found to be necessary to maintain the device within the manufacturer's recommended operational parameters under a simulated normal physiological setting of mild and severe right ventricular (RV) failure. We hypothesize that 40 cm of outflow conduit, laid down along the diaphragm and then up over the RV to reach the pulmonary trunk, will generate sufficient resistance to maintain normal pump function.
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View more >Implantable left ventricular assist devices (LVADs) have been adapted clinically for right-sided mechanical circulatory support (RVAD). Previous studies on RVAD support have established the benefits of outflow cannula restriction and rotational speed reduction, and recent literature has focused on assessing either the degree of outflow cannula restriction required to simulate left-sided afterload, or the limitation of RVAD rotational speeds. Anecdotally, the utility of outflow cannula restriction has been questioned, with suggestion that banding may be unnecessary and may be replaced simply by varying the outflow conduit length. Furthermore, many patients have a high pulmonary vascular resistance (PVR) at the time of ventricular assist device (VAD) insertion that reduces with pulmonary vascular bed remodeling. It is therefore important to assess the potential changes in flow through an RVAD as PVR changes. In this in vitro study, we observed the use of dual HeartWare HVAD devices (HeartWare Inc., Framingham, MA, USA) in biventricular support (BiVAD) configuration. We assessed the pumps' ability to maintain hemodynamic stability with and without banding; and with varying outflow cannulae length (20, 40, and 60 cm). Increased length of the outflow conduit was found to produce significantly increased afterload to the device, but this was not found to be necessary to maintain the device within the manufacturer's recommended operational parameters under a simulated normal physiological setting of mild and severe right ventricular (RV) failure. We hypothesize that 40 cm of outflow conduit, laid down along the diaphragm and then up over the RV to reach the pulmonary trunk, will generate sufficient resistance to maintain normal pump function.
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Journal Title
Artificial Organs
Volume
39
Issue
12
Copyright Statement
© 2015 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc. This is the peer reviewed version of the following article: Banding the Right Ventricular Assist Device Outflow Conduit: Is It Really Necessary With Current Devices?, Artificial Organs, Volume 39, Issue 12, December 2015, Pages 1055–1061 which has been published in final form at https://doi.org/10.1111/aor.12497. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving (http://olabout.wiley.com/WileyCDA/Section/id-828039.html)
Subject
Biomedical engineering
Biomedical engineering not elsewhere classified
Clinical sciences