An unusual presentation of left ventricular assist device thrombus

Najib, Mohammad Q.; Wong, Raymond Chi-Wing; Pierce, Christopher; DeValeria, Patrick A.; Chaliki, Hari P.

doi:10.1093/ehjci/jes011

Cited by 8 publications

(11 citation statements)

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“…The figure illustrates the regions where the thrombus preferentially accumulates, including the majority of the upstream flow straightener hub, the rear of the straightener vanes and the upstream bearing region. This finding is in good agreement with the regions in which the thrombus has been reported clinically181920 (See Fig. 3b and c).…”

Section: Resultssupporting

confidence: 91%

“…For example, it was somewhat counter-intuitive that the initial thrombus deposition in the present study occurred at the trailing edge of the stator blade, rather than within the large toroidal vortex. This finding is however consistent with clinically reported observations18. It was also surprising to observe that the thrombus propagates upstream , a phenomenon also observed in our previous simulation of thrombus growth at a site of injury in a blood vessel9 and corroborated by experimental observations30.…”

Section: Discussionsupporting

confidence: 92%

“…( a ) Simulated thrombus deposition (in red) after 6.25 hours, corresponding to a flow rate of 4.5 L/min, and a rotational speed of 9000 RPM; ( b ) and ( c ): Clinical observation of thrombus deposition in HeartMate II removed from patients1819. The correspondence is most remarkable upstream of the inlet straightener vane ( b ), and surrounding the front bearing ( c ).…”

Section: Figurementioning

confidence: 99%

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High fidelity computational simulation of thrombus formation in Thoratec HeartMate II continuous flow ventricular assist device

Yang

Wu³

et al. 2016

Sci Rep

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Continuous flow ventricular assist devices (cfVADs) provide a life-saving therapy for severe heart failure. However, in recent years, the incidence of device-related thrombosis (resulting in stroke, device-exchange surgery or premature death) has been increasing dramatically, which has alarmed both the medical community and the FDA. The objective of this study was to gain improved understanding of the initiation and progression of thrombosis in one of the most commonly used cfVADs, the Thoratec HeartMate II. A computational fluid dynamics simulation (CFD) was performed using our recently updated mathematical model of thrombosis. The patterns of deposition predicted by simulation agreed well with clinical observations. Furthermore, thrombus accumulation was found to increase with decreased flow rate, and can be completely suppressed by the application of anticoagulants and/or improvement of surface chemistry. To our knowledge, this is the first simulation to explicitly model the processes of platelet deposition and thrombus growth in a continuous flow blood pump and thereby replicate patterns of deposition observed clinically. The use of this simulation tool over a range of hemodynamic, hematological, and anticoagulation conditions could assist physicians to personalize clinical management to mitigate the risk of thrombosis. It may also contribute to the design of future VADs that are less thrombogenic.

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Section: Resultssupporting

confidence: 91%

Section: Discussionsupporting

confidence: 92%

Section: Figurementioning

confidence: 99%

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High fidelity computational simulation of thrombus formation in Thoratec HeartMate II continuous flow ventricular assist device

Yang

Wu³

et al. 2016

Sci Rep

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“…between rear hub region and entry of impeller blades, Figure 2C 8 , D 9 & F 11 , and the flow-straightener blades, Figure 2E 10 ). Previous PDIV 12 and CFD 13 studies of HMII lacked the resolution to capture these small eddies and the stagnant trajectories at the rear hub (Figure 2A & B) 12 .…”

Section: Resultsmentioning

confidence: 99%

“…4-7 In most of these cases, thrombus formation was observed at the flow-straightener and the rear hub bearing (between the flow-straightener and the impeller of the device). Typical cases are shown in explanted devices (Figure 2 (C) 8 , (D) 9 , (E) 10 & (F) 11 ).…”

Section: Introductionmentioning

confidence: 99%

Thrombus Formation Patterns in the HeartMate II Ventricular Assist Device

Chiu

Slepian²,

Bluestein

2014

ASAIO Journal

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Post-implant device thrombosis remains a life-threatening complication and limitation of continuous-flow ventricular assist devices (VADs). Utilizing advanced CFD simulations, we successfully depicted various flow patterns, recirculation zones and stagnant platelet trajectories which promote thrombus formation and observed that they matched actual thrombus formation patterns observed in Thoratec© HeartMate II™ VADs explanted from patients with pump thrombosis. Previously, these small eddies could not be captured by either DPIV or CFD due to insufficient resolution. Our study successfully demonstrated the potential capability of advanced CFD to be adopted for device optimization, leading to enhanced safety and efficacy of VADs for long-term destination therapy.

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The Effect of Flow Field on the Initial Formation of Thrombus in Ventricular Assist Devices

Meng,

Chen,

Zheng

et al. 2023

Adv Materials Inter

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Thrombosis is the main reason for the failure of ventricular assist devices (VADs). It has been acknowledged that the platelet activation induced by the nonphysiological blood flow leads to the increased thrombotic risk. However, due to the complicated influence of the VADs’ flow field and the difficulty in real‐time in situ observation, the mechanisms and process of thrombus formation in VADs remain unclear. In this work, the process of thrombus formation in VADs in vitro experiments is observed. The thrombus is found to form on the middle of the inlet guide vanes first and it is mainly caused by the immediate activation of platelets induced by the high shear rate of the flow field around the vanes and also affected by the rotation of the impeller. Then, subsequent thrombus is found in the tail of guide vanes and around the axle journal, where the blood flow is stagnated and the platelets are activated by the accumulated bioagonists. These findings clarify that the thrombus formed on the inlet guide vanes and the axle journal are dominated by two different mechanisms. This work provides unique insights into the initial formation of the thrombus on VADs and helps to reduce the thrombotic risk.

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An unusual presentation of left ventricular assist device thrombus

Cited by 8 publications

References 0 publications

High fidelity computational simulation of thrombus formation in Thoratec HeartMate II continuous flow ventricular assist device

High fidelity computational simulation of thrombus formation in Thoratec HeartMate II continuous flow ventricular assist device

Thrombus Formation Patterns in the HeartMate II Ventricular Assist Device

The Effect of Flow Field on the Initial Formation of Thrombus in Ventricular Assist Devices

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