In Vivo Observation of Cavitation on Prosthetic Heart Valves

Zapanta, Conrad M.; Stinebring, David R.; Sneckenberger, D. S.; Deutsch, Steven; Geselowitz, David B.; Tarbell, John M.; Snyder, Alan J.; Rosenberg, Gerson; Weiss, Jason; Pae, Walter E.; Pierce, William S.

doi:10.1097/00002480-199609000-00047

Cited by 39 publications

(18 citation statements)

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“…Furthermore, the volume of blood exposed to leakage flow may range from 125 to 166 mL/min. The local pressure transient on the inflow side of the mitral mechanical valve can act in combination with characteristic flows such as regurgitant jets and vortices to produce blood damage by cavitation [17]. The ensemble-averaged pressure drop measured 1 cm away from the tip of the leaflet was 518 6 79 mmHg.…”

Section: Discussionmentioning

confidence: 99%

“…Studies by Baldwin et al [13], Maymir et al [14] and Meyer [15] demonstrated, for valve implants and for valves within pulsatile ventricular assist devices, that normal Reynolds stresses caused by regurgitant flow through mechanical prostheses can exceed 20,000 dynes/cm 2 , well above the threshold for hemolysis. Cavitation, which involves the formation and collapse of vaporous bubbles in low pressure regions, is sometimes observed near mechanical mitral valves at closure and is known to cause hemolysis [16,17]. Cavitation potential is dependent on valve design and often coincides with rapid valve deceleration (water hammer) [18], squeeze flow about valve stops [19,20], and vortex motion [21].…”

Section: Introductionmentioning

confidence: 99%

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Near Valve Flows and Potential Blood Damage During Closure of a Bileaflet Mechanical Heart Valve

Herbertson

Deutsch

Manning

2011

Journal of Biomechanical Engineering

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Blood damage and thrombosis are major complications that are commonly seen in patients with implanted mechanical heart valves. For this in vitro study, we isolated the closing phase of a bileaflet mechanical heart valve to study near valve fluid velocities and stresses. By manipulating the valve housing, we gained optical access to a previously inaccessible region of the flow. Laser Doppler velocimetry and particle image velocimetry were used to characterize the flow regime and help to identify the key design characteristics responsible for high shear and rotational flow. Impact of the closing mechanical leaflet with its rigid housing produced the highest fluid stresses observed during the cardiac cycle. Mean velocities as high as 2.4 m/s were observed at the initial valve impact. The velocities measured at the leaflet tip resulted in sustained shear rates in the range of 1500-3500 s À1 , with peak values on the order of 11,000-23,000 s À1. Using velocity maps, we identified regurgitation zones near the valve tip and through the central orifice of the valve. Entrained flow from the transvalvular jets and flow shed off the leaflet tip during closure combined to generate a dominant vortex posterior to both leaflets after each valve closing cycle. The strength of the peripheral vortex peaked within 2 ms of the initial impact of the leaflet with the housing and rapidly dissipated thereafter, whereas the vortex near the central orifice continued to grow during the rebound phase of the valve. Rebound of the leaflets played a secondary role in sustaining closure-induced vortices.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Near Valve Flows and Potential Blood Damage During Closure of a Bileaflet Mechanical Heart Valve

Herbertson

Deutsch

Manning

2011

Journal of Biomechanical Engineering

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“…Echocardiographic microbubbles due to cavitation or degassing have not been previously reported in patients with continuous-flow LVADs, but cavitation has been detected at the inflow valve of pulsatile-flow LVADs implanted into cows, and flow conditions that caused higher rates of cavitation were also associated with hemolysis. 8 Hemolysis in patients with the HeartMate II device should raise the suspicion of pump thrombosis, but other causes of turbulent flow such as outflow graft kinking, aortic insufficiency, or inflow cannula malpositioning may also cause this finding. Any of these causes of increased shear stress could theoretically also be associated with the extreme pressure gradients necessary to produce microbubbles.…”

Section: Discussionmentioning

confidence: 99%

The Presence of Air Bubbles in the Aorta of a Patient with a HeartMate II Left Ventricular Assist Device

Davis

Banerjee³

2014

ASAIO Journal

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Microbubbles formed by cavitation have been frequently reported in patients with mechanical heart valves, but have not previously been described in patients with continuous-flow left-ventricular assist devices (LVADs). Obstruction of the LVAD circuit by thrombus, outflow graft kinking, or cannula malposition may cause high-pressure gradients and turbulent flow, often resulting in hemolysis. The article is the first in the field to describe the presence of microbubbles in the ascending aorta of a patient with severe LVAD-associated hemolysis. It is proposed that these bubbles were formed by cavitation in the presence of a high-pressure gradient due to LVAD outflow graft obstruction and suggested that this may be a novel imaging sign of LVAD obstruction in patients with continuous-flow LVADs.

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“…It also has the potential of in-vivo application. 29 Some MHV manufacturers have attempted to use the acoustic method to detect the existence or onset of cavitation, and submitted the results to FDA for premarket approval (PMA); however, these results have not been accepted by FDA to date. The primary concern is that not only does cavitation generate high-frequency noise, but also does the mechanical action of valve closing.…”

Section: Introductionmentioning

confidence: 99%

On the Closing Sounds of a Mechanical Heart Valve

Herman

Retta

et al. 2005

Ann Biomed Eng

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In the 1994 Replacement Heart Valve Guidance of the U.S. Food and Drug Administration (FDA), in-vitro testing is required to evaluate the potential for cavitation damage of a mechanical heart valve (MHV). To fulfill this requirement, the stroboscopic high-speed imaging method is commonly used to visualize cavitation bubbles at the instant of valve closure. The procedure is expensive; it is also limited because not every cavitation event is detected, thus leaving the possibility of missing the whole cavitation process. As an alternative, some researchers have suggested an acoustic cavitation-detection method, based on the observation that cavitation noise has a broadband spectrum. In practice, however, it is difficult to differentiate between cavitation noise and the valve closing sound, which may also contain high-frequency components. In the present study, the frequency characteristics of the closing sound in air of a Björk-Shiley Convexo-Concave (BSCC) valve are investigated. The occluder closing speed is used as a control parameter, which is measured via a laser sweeping technique. It is found that for the BSCC valve tested, the distribution of the sound energy over its frequency domain changes at different valve closing speeds, but the cut-off frequency remains unchanged at 123.32 +/- 6.12 kHz. The resonant frequencies of the occluder are also identified from the valve closing sound.

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In Vivo Observation of Cavitation on Prosthetic Heart Valves

Cited by 39 publications

References 0 publications

Near Valve Flows and Potential Blood Damage During Closure of a Bileaflet Mechanical Heart Valve

Near Valve Flows and Potential Blood Damage During Closure of a Bileaflet Mechanical Heart Valve

The Presence of Air Bubbles in the Aorta of a Patient with a HeartMate II Left Ventricular Assist Device

On the Closing Sounds of a Mechanical Heart Valve

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