Estimation of Left Ventricular Stroke Work for Rotary Left Ventricular Assist Devices

Eric L Wu; Martin Maw; Andrew F Stephens; Michael C Stevens; John F Fraser; Geoffrey Tansley; Francesco Moscato; Shaun D Gregory

doi:10.1097/MAT.0000000000001972

Estimation of Left Ventricular Stroke Work for Rotary Left Ventricular Assist Devices

ASAIO J. 2023 Sep 1;69(9):817-826. doi: 10.1097/MAT.0000000000001972. Epub 2023 May 16.

Authors

Eric L Wu^{1

2}, Martin Maw³, Andrew F Stephens^{4

5}, Michael C Stevens^{1

6}, John F Fraser^{1

2}, Geoffrey Tansley^{1

7}, Francesco Moscato^{8

9}, Shaun D Gregory^{4

5}

Affiliations

¹ From the Innovative Cardiovascular Engineering and Technology Laboratory (ICETLAB), Critical Care Research Group, The Prince Charles Hospital, Chermside, Queensland, Australia.
² School of Medicine, The University of Queensland, Queensland, Brisbane, Australia.
³ Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.
⁴ Department of Mechanical and Aerospace Engineering, Monash University, Melbourne, Australia.
⁵ Cardio-Respiratory Engineering and Technology Laboratory, Baker Heart and Diabetes Institute, Alfred Hospital, Melbourne, Australia.
⁶ Graduate School of Biomedical Engineering, Faculty of Engineering, University of New South Wales, Sydney, New South Wales, Australia.
⁷ School of Engineering and Built Environment, Griffith University, Gold Coast, Australia.
⁸ Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria.
⁹ Austrian Cluster for Tissue Regeneration, Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, Vienna, Austria.

PMID: 37191479
DOI: 10.1097/MAT.0000000000001972

Abstract

Continuous monitoring of left ventricular stroke work (LVSW) may improve the medical management of patients with rotary left ventricular assist devices (LVAD). However, implantable pressure-volume sensors are limited by measurement drift and hemocompatibility. Instead, estimator algorithms derived from rotary LVAD signals may be a suitable alternative. An LVSW estimator algorithm was developed and evaluated in a range of in vitro and ex vivo cardiovascular conditions during full assist (closed aortic valve [AoV]) and partial assist (opening AoV) mode. For full assist, the LVSW estimator algorithm was based on LVAD flow, speed, and pump pressure head, whereas for partial assist, the LVSW estimator combined the full assist algorithm with an estimate of AoV flow. During full assist, the LVSW estimator demonstrated a good fit in vitro and ex vivo (R 2 : 0.97 and 0.86, respectively) with errors of ± 0.07 J. However, LVSW estimator performance was reduced during partial assist, with in vitro : R 2 : 0.88 and an error of ± 0.16 J and ex vivo : R 2 : 0.48 with errors of ± 0.11 J. Further investigations are required to improve the LVSW estimate with partial assist; however, this study demonstrated promising results for a continuous estimate of LVSW for rotary LVADs.

MeSH terms

Aortic Valve
Heart-Assist Devices*
Humans
Stroke*