Acoustic Properties of Axial and Centrifugal Flow Left Ventricular Assist Devices and Prediction of Pump Thrombosis.

OBJECTIVE: To characterize the properties of the audible tones produced by current left ventricular assist device (LVAD) pumps approved for use, and to ascertain if changes in those may be present in the setting of pump thrombosis. PATIENTS AND METHODS: From August 31, 2016, to January 16, 2020, LVAD recipients consented to have surface recordings obtained using a high-fidelity digital stethoscope. Audio data were analyzed using digital recording and editing software to produce an acoustic spectrogram by Fast Fourier transformation. RESULTS: Recordings were obtained in 53 patient encounters (27 HeartMate II, 19 HeartWare and 7 HeartMate 3). In 12 patients (9 HeartMate II, 3 HeartWare) there was a clinical concern for pump thrombosis. In all patients and pump models, a fundamental frequency was noted, and the second and third harmonics were also clearly detectable. Where thrombosis occurred in the HeartMate II pump, the absolute (normal -46.9 [-57.5,-42.9] dB vs thrombosis -41.4 [-49.8,-26.8] dB; P=.08) and relative (normal 0.72 [0.62, 0.92] vs thrombosis 0.95 [0.86, 1.24]; P=.01) third harmonic frequencies were increased in amplitude. Where paired data were available, an increase in the absolute and relative third harmonic frequencies was observed in all patients. In the case of the HeartWare device, a consistent difference in harmonic amplitudes in the setting of thrombosis could not be identified. CONCLUSION: A consistent pattern of fundamental and harmonic frequencies is common to all LVADs currently approved for use. Alterations in the amplitude of higher order harmonics may signal the onset of pump thrombosis in axial flow LVADs.

Palliative Care Clinicians Caring for Patients Before and After Continuous Flow-Left Ventricular Assist Device.

Left ventricular assist devices (LVADs) are an available treatment option for carefully selected patients with advanced heart failure. Initially developed as a bridge to transplantation, LVADs are now also offered to patients ineligible for transplantation as destination therapy (DT). Individuals with a DT-LVAD will live the remainder of their lives with the device in place. Although survival and quality of life improve with LVADs compared with medical therapy, complications persist including bleeding, infection, and stroke. There has been increased emphasis on involving palliative care (PC) specialists in LVAD programs, specifically the DT-LVAD population, from the pre-implantation process through the end of life. Palliative care specialists are well poised to provide education, guidance, and support to patients, families, and clinicians throughout the LVAD journey. This article addresses the complexities of the LVAD population, describes key challenges faced by PC specialists, and discusses opportunities for building collaboration between PC specialists and LVAD teams.