Cavitation in left ventricular assist device patients: a potential early sign of pump thrombosis

Zuin, Marco; Rigatelli, Gianluca; Braggion, Gabriele; Bacich, Daniela; Nguyen, Thach

doi:10.1007/s10741-019-09884-0

Cited by 4 publications

(9 citation statements)

References 28 publications

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“…The fact that cavitation has occurred at the investigated relative inlet pressures may seem remarkable, as cavitation, theoretically, should not occur before the pressure falls below the vapor pressure 8–11 . At a water temperature of 37°C, the vapor pressure is 47 mmHg 22 .…”

Section: Discussionmentioning

confidence: 87%

“…When the pressure in the pump falls below the critical value for blood cavitation, it leads to the creation of microbubbles which may act as gaseous microemboli (GME) or collapse when encountering high‐pressure areas before reaching the circulation. The collapse releases large amounts of energy potentially leading to hemolysis, endothelial damage of vascular structures, and damage to the LVAD 8–11 …”

Section: Introductionmentioning

confidence: 99%

“…Today, the presence of larger microbubbles has been visualized and reported in the ascending aorta using echocardiography. This method has limitations as echocardiography only results in a picture at a given time and only can be performed at routine follow‐up 10,12 . To counter this limitation, continuous measurement would be advantageous, ensuring a rapid response to reduce the clinical consequences.…”

Section: Introductionmentioning

confidence: 99%

“…Previous studies describe how vibration measurement is an effective method for continuously detecting cavitation in industrial centrifugal pumps. Vibration measurement exploits that the microbubble collapse inside the pump increases vibration and noise levels of the pump, which can be detected with accelerometers 10,13–18 …”

Section: Introductionmentioning

confidence: 99%

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Vibrational characterization of cavitation in left ventricular assist device

et al. 2023

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BackgroundThe left ventricular assist device (LVAD) is a mechanical circulatory support device for patients with severe heart failure. Microbubbles caused by cavitation in the LVAD can potentially lead to physiological and pump‐related complications. The aim of this study is to characterize the vibrational patterns in the LVAD during cavitation.MethodsThe LVAD was integrated into an in vitro circuit and mounted with a high‐frequency accelerometer. Accelerometry signals were acquired with different relative pump inlet pressures ranging from baseline (+20 mmHg) to −600 mmHg in order to induce cavitation. Microbubbles were monitored with dedicated sensors at the pump inlet and outlet to quantify the degree of cavitation. Acceleration signals were analyzed in the frequency domain to identify changes in the frequency patterns when cavitation occurred.ResultsSignificant cavitation occurred at the low inlet pressure (−600 mmHg) and was detected in the frequency range between 1800 and 9000 Hz. Minor degrees of cavitation at higher inlet pressures (−300 to −500 mmHg) were detected in the frequency range between 500–700, 1600–1700 Hz, and around 12 000 Hz. The signal power of the dominating frequency ranges was statistically significantly different from baseline signals.ConclusionVibrational measurements in the LVAD can be used to detect cavitation. A significant degree of cavitation could be detected in a wide frequency range, while minor cavitation activity could only be detected in more narrow frequency ranges. Continuous vibrational LVAD monitoring can potentially be used to detect cavitation and minimize the damaging effect associated with cavitation.

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Section: Discussionmentioning

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Vibrational characterization of cavitation in left ventricular assist device

et al. 2023

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“…As we previously demonstrated, a rheological phenomenon called cavitation is generated by both concentric and eccentric coronary artery stenosis (≥75% for the former and ≥50% for the latter) which propagates downstream the vessel, creating microbubbles which exploded when the fluid pressure was lower than the vapor pressure at a local thermodynamic state [6]. Biomechanically, cavitation might damage endothelial surfaces and promote thrombosis, as observed in subjects with left ventricular assist device (LVAD) [7]. In the present manuscript we sought to assess, using numer-ical and computational fluid dynamic analysis (CFD), the potential of cavitation to both induce damage to coronary artery endothelium and to promote atherosclerotic plaque progression.…”

Section: Introductionmentioning

confidence: 99%

Coronary artery cavitation as a trigger for atherosclerotic plaque progression: a simplified numerical and computational fluid dynamic demonstration

Rigatelli¹,

Zuin²,

Bilato³

et al. 2022

Rev. Cardiovasc. Med.

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Backgrounds: Coronary cavitation is supposed to be generated by both concentric and eccentric coronary artery stenosis which propagates downstream the vessel, creating microbubbles which exploded when the fluid pressure was lower than the vapor pressure at a local thermodynamic state. Objective: To assess, using numerical and computational fluid dynamic analysis (CFD), the potential of cavitation to both induce damage to coronary artery endothelium and to promote atherosclerotic plaque progression. Methods: We retrospectively reviewed the data 12 consecutive patients evaluated between 1st January 2013 and 1st January 2014 with an isolated hemodynamically significant Left Main (LM) disease. The patient specific geometries have been reconstructed. Bubble velocity has been calculated in accordance with Newton's second law. Both the forces arising from the bubbles' interaction with the continuous phase and impact with the endothelium have been evaluated. The impact of turbulence on the motion of bubbles have been modelled with a dispersion model. Results: Among the 12 patients retrospectively analysed [8 males, mean age 68.2 ± 12.8 years old], the mean LM stenosis was 72.3 ± 3.6%. As expected, in all subjects, LM stenoses induced cavitation which propagates downstream the vessel creating microbubbles. The higher concentration of vapor region was detected before the carina (within 0.8 to 1.3 cm from the stenosis). Due to the pressure gradient generated by the stenosis, formation of a re-entry jet which penetrates each bubble generated a shock wave. Before the carina, the mean bubbles radius observed was 4.2 ± 1.4 µm, which generated a mean peak pressure of 3.9 ± 0.5 MPa when they explode. Conclusion:The cavitation phenomenon is effectively generated in a model of LM bifurcation and instantaneous pressure-peaks due to collapses of vapor bubbles resulted in a measurable dynamic load on vessel wall potentially able to induce endothelial damage.

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