Detection of inflow obstruction in left ventricular assist devices by accelerometer: A porcine model study

BACKGROUND: Left ventricular assist devices (LVAD) provide circulatory blood pump support for severe heart failure patients. Pump inflow obstructions may lead to stroke and pump malfunction. We aimed to verify in vivo that gradual inflow obstructions, representing prepump thrombosis, are detect-able by a pump-attached accelerometer, where the routine use of pump power (PLVAD) is deficient.METHOD: In a porcine model (n = 8), balloon-tipped catheters obstructed HVAD inflow conduits by 34% to 94% in 5 levels. Afterload increases and speed alterations were conducted as controls. We com-puted nonharmonic amplitudes (NHA) of pump vibrations captured by the accelerometer for the analy-sis. Changes in NHA and PLVAD were tested by a pairwise nonparametric statistical test. Detection sensitivities and specificities were investigated by receiver operating characteristics with areas under the curves (AUC).RESULTS: NHA remained marginally affected during control interventions, unlike PLVAD. NHA ele-vated during obstructions within 52-83%, while mass pendulation was most pronounced. Meanwhile, PLVAD changed far less. Increased pump speeds tended to amplify the NHA elevations. The corre-sponding AUC was 0.85-1.00 for NHA and 0.35-0.73 for PLVAD.CONCLUSION: Elevated NHA provides a reliable indication of subclinical gradual inflow obstructions. The accelerometer can potentially supplement PLVAD for earlier warnings and localization of pump. J Heart Lung Transplant 2023;42:1005-1014 & COPY; 2023 The Author(s). Published by Elsevier Inc. on behalf of International Society for Heart and Lung Transplantation. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

Automated summary

In a porcine model experiment, it was found that the changes in nonharmonic amplitudes (NHA) captured by the accelerometer can provide a reliable indication of subclinical gradual inflow obstructions, potentially supplementing PLVAD for earlier warnings and localization of pump.