Passive control of a biventricular assist device with compliant inflow cannulae

Shaun David Gregory, Mark John Pearcy, Daniel Timms

Research output: Contribution to journalArticleResearchpeer-review

13 Citations (Scopus)

Abstract

Rotary ventricular assist device (VAD) support of the cardiovascular system is susceptible to suction events due to the limited preload sensitivity of these devices. This may be of particular concern with rotary biventricular support (BiVAD) where the native, flow balancing Starling response is diminished in both ventricles. The reliability of sensor and sensorless-based control systems which aim to control VAD flow based on preload has limitations, and, thus, an alternative solution is desired. This study introduces a compliant inflow cannula (CIC) which could improve the preload sensitivity of a rotary VAD by passively altering VAD flow depending on preload. To evaluate the design, both the CIC and a standard rigid inflow cannula were inserted into a mock circulation loop to enable biventricular heart failure support using configurations of atrial and ventricular inflow, and arterial outflow cannulation. A range of left (LVAD) and right VAD (RVAD) rotational speeds were tested as well as step changes in systemic/pulmonary vascular resistance to alter relative preloads, with resulting flow rates recorded. Simulated suction events were observed, particularly at higher VAD speeds, during support with the rigid inflow cannula, while the CIC prevented suction events under all circumstances. The compliant section passively restricted its internal diameter as preload was reduced, which increased the VAD circuit resistance and thus reduced VAD flow. Therefore, a CIC could potentially be used as a passive control system to prevent suction events in rotary left, right, and biventricular support.

Original languageEnglish
Pages (from-to)683-690
Number of pages8
JournalArtificial Organs
Volume36
Issue number8
DOIs
Publication statusPublished - 1 Aug 2012
Externally publishedYes

Keywords

  • Biventricular assist device
  • Compliant cannula
  • Heart failure
  • Physiological control
  • Suction event

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