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.

Ventricular tachycardia and preload deficiency post LVAD - The importance of integrated assessment.

Ventricular tachycardia (VT) is common in LVAD recipients, and although often well tolerated, may result in symptoms and ICD therapies, and therefore require further evaluation and treatment. However, preload deficiency may also contribute to the development of ventricular tachycardia after LVAD implantation by provoking inflow cannula related VT. In this report, three cases are described where ventricular tachycardia was evaluated by integrated assessment utilizing echo and the HeartWare HVAD console, and successfully treated by modification of LV loading conditions.

Decreased bed rest post-percutaneous coronary intervention with a 7-French arterial sheath and its effects on vascular complications.

AIMS AND OBJECTIVES: To compare the incidence of femoral access puncture site complications in the control group, who underwent 6 hr of bed rest, with patients in the case group, who underwent 4 hr of bed rest. BACKGROUND: The ideal bed rest length after percutaneous coronary intervention with a 7-French arterial sheath has been investigated by nursing practice. However, in this larger-sheath-size group, best practices have not been determined, and bed rest time continues to vary markedly among institutions. DESIGN: Retrospective study. METHODS: Data were retrieved from the National Cardiovascular Data Registry and electronic health records in this retrospective study. Sample size was 401 patients: 152 case patients with 4-hr bed rest and 249 controls with 6-hr bed rest. Case group data were obtained from 20 May 2013-31 December 2014; and control group data, 15 June 2011-20 May 2013. RESULTS: National Cardiovascular Data Registry event rates were generally low in both groups: Only three patients in each group had a bleeding event within 72 hr (2% vs. 1%) and no patient and only two controls had arteriovenous fistula (0% vs. 1%). Complications documented in the electronic health records with institutional femoral access puncture site complication definitions identified bleeding at the access site in eight case patients (5%) and nine controls (4%). Haematoma at the access site occurred in 21 case patients (14%) and 25 controls (10%). CONCLUSIONS: The practice change of decreasing bed rest from 6-4 hr for patients with 7-French arterial sheaths post-percutaneous coronary intervention was associated with no significant change in femoral access puncture site complications in either National Cardiovascular Data Registry data or institutional electronic health records data. RELEVANCE TO CLINICAL PRACTICE: This introduces expanded evidence of safety in decreasing bed rest length in larger (7-French) arterial sheaths post-percutaneous coronary intervention.