Acoustic Spectral Analysis for Determining Pump Thrombosis in Rotary Blood Pumps

Kaufmann, Friedrich; Hörmandinger, Christoph; Stepanenko, Alexander; Kretzschmar, Alexandra; Soltani, Sajjad; Krabatsch, Thomas; Potapov, Evgenij; Hetzer, Roland

doi:10.1097/mat.0000000000000097

Cited by 45 publications

(56 citation statements)

References 15 publications

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“…However, the spectra presented in the paper included low‐frequency information. In figures 1 and 3 in the paper of Kaufmann et al , it is observed that the lowest frequency modes are smaller than (about 7 Hz in their figure 1) or equal to (about 10 Hz in their figure 3) the pump rotation frequency. For the pump considered, the authors show that the most indicative condition for pump thrombosis is the existence of a third harmonic of the pump rotation rate, not present in the control group ( P < 0.0001).…”

Section: Discussionmentioning

confidence: 87%

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Detection of Thrombosis in the Extracorporeal Membrane Oxygenation Circuit by Infrasound: Proof of Concept

et al. 2016

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As of today, there exist no reliable, objective methods for early detection of thrombi in the extracorporeal membrane oxygenators (ECMO) system. Within the ECMO system, thrombi are not always fixed to a certain component or location in the circuit. Thus, clot fragments of different shapes and consistencies may circulate and give rise to vibrations and sound generation. By bedside sound measurements and additional laboratory experiments (although not detailed herein), we found that the presence of particles (clots or aggregates and fragments of clots) can be detected by analyzing the strength of infra‐sound (< 20 Hz) modes of the spectrum near the inlet and outlet of the centrifugal pump in the ECMO circuit. For the few patients that were considered in this study, no clear false positive or negative examples were found when comparing the spectral approach with clinical observations. A laboratory setup provided insight to the flow in and out of the pump, confirming that in the presence of particles a low‐amplitude low‐frequency signal is strongly amplified, enabling the identification of a clot.

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Section: Discussionmentioning

confidence: 87%

“…The idea of using acoustic data to aid clinical decision‐making is by no means new. Such means have been proposed for detecting end‐of‐life of LVAD , and detecting thrombosis in implant rotary blood pumps (8,9). Carrying out an in vivo study, Kaufmann et al considered the sound signature of the HeartWare (Framingham, MA, USA) HVAD LVAD System.…”

mentioning

confidence: 99%

Detection of Thrombosis in the Extracorporeal Membrane Oxygenation Circuit by Infrasound: Proof of Concept

et al. 2016

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“…In 2003, Tanishiro et al 20 showed that arterial sound can be used to detect malrotation in centrifugal LVADs in an in vitro setup, and in 2007, Slaughter et al 21 showed that acoustic changes predicted impending device malfunction in the pulsatile HeartMate XVE. Recently, Hubbert et al 22 showed significant differences in HeartMate II acoustics when inflow and outflow tubing were subject to artificial stenosis and when artificial clots were passed through the pump, and Kaufmann et al 23 showed that thrombus formation in HeartWare ventricular assist device pumps was associated with telltale changes in acoustic spectra. Similar data collection techniques were used in all studies, although particular equipment differed.…”

Section: Discussionmentioning

confidence: 98%

Acoustic Characterization of Axial Flow Left Ventricular Assist Device Operation In Vitro and In Vivo

Yost¹,

Royston

Bhat³

et al. 2016

ASAIO Journal

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The use of left ventricular assist devices (LVADs), implantable pumps used to supplement cardiac output, has become an increasingly common and effective treatment for advanced heart failure. Although modern continuous-flow LVADs improve quality of life and survival more than medical management of heart failure, device malfunction remains a common concern. Improved noninvasive methods for assessment of LVAD function are needed to detect device complications. An electronic stethoscope was used to record sounds from the HeartMate II axial flow pump in vitro and in vivo. The data were then uploaded to a computer and analyzed using two types of acoustic analysis software. Left ventricular assist device acoustics were quantified and were related to pump speed, acoustic environment, and inflow and outflow graft patency. Peak frequency values measured in vivo were found to correlate strongly with both predicted values and in vitro measurements (r > 0.999). Plots of the area under the acoustic spectrum curve, obtained by integrating over 50 Hz increments, showed strong correlations between in vivo and in vitro measurements (r > 0.966). Device thrombosis was found to be associated with reduced LVAD acoustic amplitude in two patients who underwent surgical device exchange. ASAIO Journal 2016; 62:46-55.

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“…Various approaches have been proposed to detect and monitor for thrombus inside blood pumps . Near‐infrared light has traditionally been used as a noninvasive diagnostic tool for clarifying blood components.…”

Section: Discussionmentioning

confidence: 99%

“…Although various approaches have been proposed to detect thrombus inside blood pumps , no established methods currently exist for timely detection of pump thrombus. As thrombus detection may guide clinical management and appropriate ranges of anticoagulation tailored for patients and the various types of MCS devices in use , there is a strong need for tools to detect and monitor pump thrombus in real time.…”

mentioning

confidence: 99%

Optical Dynamic Analysis of Thrombus Inside a Centrifugal Blood Pump During Extracorporeal Mechanical Circulatory Support in a Porcine Model

Fujiwara¹,

Sakota

Ohuchi

et al. 2017

Artificial Organs

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Complications due to pump thrombus remain the weak point of mechanical circulatory support (MCS), such as the use of a left ventricular assist device (LVAD) or extracorporeal membrane oxygenation, leading to poor outcomes. Hyperspectral imaging (HSI) is an effective imaging method using a hyperspectral (HS) camera, which comprises a spectrophotometer and a charge-coupled device camera to discriminate thrombus from whole blood. Animal experiments were conducted to analyze dynamic imaging of thrombus inside a prototype of a hydrodynamically levitated centrifugal blood pump using an HSI system. Six pigs were divided into a venous circulation group (n = 3) and an arterial circulation group (n = 3). Inflow and outflow cannulae were inserted into the jugular veins in the venous circulation group. The latter simulated an LVAD application. To create thrombogenic conditions, pump flow was maintained at 1 L/min without anticoagulation. An image of the bottom surface of the pump was captured by the HS camera every 4 nm over the wavelength range of 608-752 nm. Real-time dynamic images of the inside of the pump were displayed on the monitor. Appearance of an area displaying thrombus was detected within 24 h after the start of the circulation in every experiment. This imaging system also succeeded in determining the origins of pump thrombus: from inside the pump in two cases, and from outside in four cases. Two main possible sources of pump thrombus originating outside the pump were identified on autopsy: wedge thrombus around the inflow cannula; and string-like thrombus at the junction between the pump inlet and circuit tube. The results of this study from close observation of the changing appearance of pump thrombus may contribute to improvements in the safety of extracorporeal MCS.

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Acoustic Spectral Analysis for Determining Pump Thrombosis in Rotary Blood Pumps

Cited by 45 publications

References 15 publications

Detection of Thrombosis in the Extracorporeal Membrane Oxygenation Circuit by Infrasound: Proof of Concept

Detection of Thrombosis in the Extracorporeal Membrane Oxygenation Circuit by Infrasound: Proof of Concept

Acoustic Characterization of Axial Flow Left Ventricular Assist Device Operation In Vitro and In Vivo

Optical Dynamic Analysis of Thrombus Inside a Centrifugal Blood Pump During Extracorporeal Mechanical Circulatory Support in a Porcine Model

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