Left Ventricular Assist Device Inflow Cannula Angle and Thrombosis Risk

Chivukula, Venkat Keshav; Beckman, Jennifer; Prisco, Anthony R.; Dardas, Todd; Lin, Shin; Smith, Jason W.; Mokadam, Nahush A.; Aliseda, Alberto; Mahr, Claudius

doi:10.1161/circheartfailure.117.004325

Cited by 75 publications

(84 citation statements)

References 32 publications

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“…Other authors have also implicated LV size and devicerelated factors as important for pump thrombosis, and these factors would not necessarily be addressed with current surgical strategies for pump exchange. [25][26][27] Our own results lend credence to this theory.…”

Section: Discussionsupporting

confidence: 77%

Recurrent pump thrombosis is common after axial continuous-flow left ventricular assist device exchange

Urban

Moulton

et al. 2019

Int J Artif Organs

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In selected patients with left ventricular assist device–associated infection or malfunction, pump exchange may become necessary after conservative treatment options fail and heart transplantation is not readily available. We examined the survival and complication rate in patients (⩾19 years of age) who underwent HeartMate II to HeartMate II exchange at our institution from 1 January 2010 to 28 February 2018. Clinical outcomes were analyzed and compared for patients who underwent exchange for pump thrombosis (14 patients), breach of driveline integrity (5 patients), and device-associated infection (2 patients). There were no differences in 30-day mortality (p = 0.58), need for temporary renal replacement therapy (p = 0.58), right ventricular mechanical support (p = 0.11), and postoperative stroke (p = 0.80) among groups. Survival at 1 year was 90% ± 7% for the whole cohort and 85% ± 10% for those who underwent exchange for pump thrombosis. In patients exchanged for device thrombosis, freedom from re-thrombosis and survival free from pump re-thrombosis at 1 year were 49% ± 16% and 42% ± 15%, respectively. No association of demographic and clinical variables with the risk of recurrent pump thrombosis after the first exchange was identified. Survival after left ventricular assist device exchange compares well with published results after primary left ventricular assist device implantation. However, recurrence of thrombosis was common among patients who required a left ventricular assist device exchange due to pump thrombosis. In this sub-group, consideration should be given to alternative strategies to improve the outcomes.

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Section: Discussionsupporting

confidence: 77%

Recurrent pump thrombosis is common after axial continuous-flow left ventricular assist device exchange

Urban

Moulton

et al. 2019

Int J Artif Organs

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“…To date, the effect of inflow cannula malposition in the left ventricle (LV) has been identified as an important component associated with thrombosis in LVAD patients. [24][25][26][27] On the other hand, no studies have specifically addressed the prothrombotic interplay between LV cannulation and residual contractility of the pathologic heart failure LV. We developed a computational platform to characterize patient-specific intraventricular hemodynamics in the LVAD-implanted LV, accounting for potential mechanisms related to thrombus formation as a consequence of limited ventricular contractility.…”

Section: Prothrombotic Hemodynamic Conditions In the Lvad-implanted Lmentioning

confidence: 99%

Blood damage in Left Ventricular Assist Devices: Pump thrombosis or system thrombosis?

et al. 2018

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Introduction: Despite significant technical advancements in the design and manufacture of Left Ventricular Assist Devices, post-implant thrombotic and thromboembolic complications continue to affect long-term outcomes. Previous efforts, aimed at optimizing pump design as a means of reducing supraphysiologic shear stresses generated within the pump and associated prothrombotic shear-mediated platelet injury, have only partially altered the device hemocompatibility. Methods: We examined hemodynamic mechanisms that synergize with hypershear within the pump to contribute to the thrombogenic potential of the overall Left Ventricular Assist Device system. Results: Numerical simulations of blood flow in differing regions of the Left Ventricular Assist Device system, that is the diseased native left ventricle, the pump inflow cannula, the impeller, the outflow graft and the anastomosed downstream aorta, reveal that prothrombotic hemodynamic conditions might occur at these specific sites. Furthermore, we show that beyond hypershear, additional hemodynamic abnormalities exist within the pump, which may elicit platelet activation, such as recirculation zones and stagnant platelet trajectories. We also provide evidences that particular Left Ventricular Assist Device implantation configurations and specific post-implant patient management strategies, such as those allowing aortic valve opening, are more hemodynamically favorable and reduce the thrombotic risk. Conclusion: We extend the perspective of pump thrombosis secondary to the supraphysiologic shear stress environment of the pump to one of Left Ventricular Assist Device system thrombosis, raising the importance of comprehensive characterization of the different prothrombotic risk factors of the total system as the target to achieve enhanced hemocompatibility and improved clinical outcomes.

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“…Non-physiological flow patterns in LVAD patients and abnormal stagnation areas within the ventricle were previously identified in experimental flow models, 22,23 in CFD models. 24–26 However, since there is no clinical method applicable for LVAD patients to visualize the ventricular flow fields, in-vitro experiments and numerical simulations are still important tools for gaining insights into the flow patterns with specific limitations.…”

Section: Discussionmentioning

confidence: 99%

“…The simulation of the intraventricular flow field has been performed with the LAM method. 24,26 However, the FDA nozzle study identified issues for Re numbers larger than 500 in predicting main flow features downstream of an expansion. 15 Due to the highly dynamic flow already at the mitral inflow into the LV, it is impossible to identify one method that perfectly fits.…”

Section: Discussionmentioning

confidence: 99%

Validation of numerically simulated ventricular flow patterns during left ventricular assist device support

et al. 2020

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Intraventricular flow patterns during left ventricular assist device support have been investigated via computational fluid dynamics by several groups. Based on such simulations, specific parameters for thrombus formation risk analysis have been developed. However, computational fluid dynamic simulations of complex flow configurations require proper validation by experiments. To meet this need, a ventricular model with a well-defined inflow section was analyzed by particle image velocimetry and replicated by transient computational fluid dynamic simulations. To cover the laminar, transitional, and turbulent flow regime, four numerical methods including the laminar, standard k-omega, shear-stress transport, and renormalized group k-epsilon were applied and compared to the particle image velocimetry results in 46 different planes in the whole left ventricle. The simulated flow patterns for all methods, except renormalized group k-epsilon, were comparable to the flow patterns measured using particle image velocimetry (absolute error over whole left ventricle: laminar: 10.5, standard k-omega: 11.3, shear–stress transport: 11.3, and renormalized group k-epsilon: 17.8 mm/s). Intraventricular flow fields were simulated using four numerical methods and validated with experimental particle image velocimetry results. In the given setting and for the chosen boundary conditions, the laminar, standard K-omega, and shear–stress transport methods showed acceptable similarity to experimental particle image velocimetry data, with the laminar model showing the best transient behavior.

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Left Ventricular Assist Device Inflow Cannula Angle and Thrombosis Risk

Cited by 75 publications

References 32 publications

Recurrent pump thrombosis is common after axial continuous-flow left ventricular assist device exchange

Recurrent pump thrombosis is common after axial continuous-flow left ventricular assist device exchange

Blood damage in Left Ventricular Assist Devices: Pump thrombosis or system thrombosis?

Validation of numerically simulated ventricular flow patterns during left ventricular assist device support

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