Detection of inflow obstruction in left ventricular assist devices by accelerometer: An in vitro study

Didrik Lilja; Itai Schalit; Andreas Espinoza; Fred-Johan Pettersen; Ole Jakob Elle; Per Steinar Halvorsen

doi:10.1016/j.medengphy.2022.103917

Detection of inflow obstruction in left ventricular assist devices by accelerometer: An in vitro study

Med Eng Phys. 2022 Dec:110:103917. doi: 10.1016/j.medengphy.2022.103917. Epub 2022 Nov 8.

Authors

Didrik Lilja¹, Itai Schalit², Andreas Espinoza³, Fred-Johan Pettersen⁴, Ole Jakob Elle⁵, Per Steinar Halvorsen²

Affiliations

¹ The Intervention Centre, Division of Technology and Innovation, Oslo University Hospital, Oslo Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway. Electronic address: didlil@ous-hf.no.
² The Intervention Centre, Division of Technology and Innovation, Oslo University Hospital, Oslo Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
³ The Intervention Centre, Division of Technology and Innovation, Oslo University Hospital, Oslo Norway.
⁴ Department of Clinical and Biomedical Engineering, Oslo University Hospital, Oslo, Norway; Department of Physics, University of Oslo, Norway.
⁵ The Intervention Centre, Division of Technology and Innovation, Oslo University Hospital, Oslo Norway; Department of Informatics, The University of Oslo, Norway.

PMID: 36564132
DOI: 10.1016/j.medengphy.2022.103917

Abstract

Inflow obstruction in left ventricular assist devices (LVAD) may lead to embolic stroke and pump malfunction. We investigated if an accelerometer detected graded LVAD inflow obstructions. Detection performances were compared to the current continuous surveillance routine based on the pump power consumption (P_LVAD). In ten mock circuit experiments, four different-sized pendulating balloons obstructed HVAD™ inflow conduits cross-section areas by 14%-75%. Nonharmonic amplitudes (NHA) of continuous signals from a triaxial accelerometer attached to the LVAD were compared against single-point P_LVAD values, using load and speed alterations as control interventions. We analyzed the NHA band power with a pairwise nonparametric statistical test. The detection performances were analyzed by receiver operating characteristics with areas under the curves (AUC). The NHA remained unaffected during load alterations. In contrast, NHA increased significantly from the 27% obstruction level (AUC≥0.82), an effect amplified by increased pump speed. P_LVAD did not change significantly below the maximal 75% obstruction level (AUC≤0.36). In conclusion, NHA detected the inflow obstructions much better than P_LVAD. The technique may provide a future monitoring modality of any pendulating obstructive inflow pathology.

Keywords: Accelerometer; Detection; Inflow obstructions; LVAD; Pump vibrations.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Accelerometry
Cannula
Heart Failure*
Heart-Assist Devices*
Humans
Thrombosis*