scholarly journals Effects of the atrium on intraventricular flow patterns during mechanical circulatory support

2021 ◽  
pp. 039139882110560
Author(s):  
Mojgan Ghodrati ◽  
Thomas Schlöglhofer ◽  
Alexander Maurer ◽  
Thananya Khienwad ◽  
Daniel Zimpfer ◽  
...  
Keyword(s):  
Shear Stress ◽  
Mitral Valve ◽  
Residence Time ◽  
Flow Patterns ◽  
Left Ventricular ◽  
Circulatory Support ◽  
Low Velocity ◽  
Ventricular Assist ◽  
Intraventricular Flow ◽  
Blood Flow Dynamics

Simulations of the ventricular flow patterns during left ventricular assist device (LVAD) support are mainly performed with idealized cylindrical inflow, neglecting the influence of the atrial vortex. In this study, the influence of the left atrium (LA) on the intra-ventricular flow was investigated via Computational Fluid Dynamics (CFD) simulations. Ventricular flow was simulated by a combined Eulerian (carrier flow)/Lagrangian (particles) approach taking into account either the LA or a cylindrical inflow section to mimic a fully support condition. The flow deviation at the mitral valve, the blood low-velocity volume as well as the residence time and shear stress history of the particles were calculated. Inclusion of the LA deflects the flow at the mitral valve by 25°, resulting in an asymmetric flow jet entering the left ventricle. This reduced the ventricular low-velocity volume by 40% (from 6.4 to 3.9 cm3), increased (40%) the shear stress experienced by particles and correspondingly increased (27%) their residence time. Under the studied conditions, the atrial geometry plays a major role in the development of intraventricular flow patterns. A reliable prediction of blood flow dynamics and consequently thrombosis risk analysis within the ventricle requires the consideration of the LA in computational simulations.

scholarly journals Intraventricular Flow Patterns in Patients Treated with Left Ventricular Assist Devices

ASAIO Journal ◽  
2020 ◽  
Vol 67 (1) ◽  
pp. 74-83
Author(s):  
Lorenzo Rossini ◽  
Oscar Ö. Braun ◽  
Michela Brambatti ◽  
Yolanda Benito ◽  
Adam Mizeracki ◽  
...  
Keyword(s):  
Flow Patterns ◽  
Left Ventricular ◽  
Ventricular Assist Devices ◽  
Left Ventricular Assist Devices ◽  
Ventricular Assist ◽  
Assist Devices ◽  
Left Ventricular Assist ◽  
Intraventricular Flow

scholarly journals Rapid Bioprosthetic Mitral Valve Failure after Temporary Left Ventricular Assist Device Support

2017 ◽  
Vol 20 (6) ◽  
pp. 256
Author(s):  
Heidi B Schubmehl ◽  
Muhamed Saric ◽  
Alan F Vainrib ◽  
Mathew Williams ◽  
Leora B Balsam
Keyword(s):  
Mitral Valve ◽  
Left Ventricular Assist Device ◽  
Ventricular Assist Device ◽  
Mechanical Circulatory Support ◽  
Left Ventricular ◽  
Circulatory Support ◽  
Assist Device ◽  
Ventricular Assist ◽  
Transcatheter Mitral Valve Replacement ◽  
Left Ventricular Assist

The technique of mechanical circulatory support or the site of cannulation may affect transvalvular flow. We describe early failure of a mitral bioprosthesis in a patient with temporary left ventricular assist device support, likely from thrombosis. Salvage with transcatheter mitral valve replacement was attempted. Temporary mechanical circulatory support strategies that maximize flow across a new bioprosthesis should be sought to avoid early valvular thrombosis.

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

2020 ◽  
Vol 44 (1) ◽  
pp. 30-38 ◽  
Author(s):  
Mojgan Ghodrati ◽  
Thananya Khienwad ◽  
Alexander Maurer ◽  
Francesco Moscato ◽  
Francesco Zonta ◽  
...  
Keyword(s):  
Shear Stress ◽  
Particle Image Velocimetry ◽  
Particle Image ◽  
Fluid Dynamic ◽  
Flow Patterns ◽  
Left Ventricular ◽  
Dynamic Simulations ◽  
Ventricular Assist ◽  
Shear Stress Transport ◽  
Image Velocimetry

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.

scholarly journals Endocrine Challenges in Patients with Continuous-Flow Left Ventricular Assist Devices

Nutrients ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 861
Author(s):  
Gennaro Martucci ◽  
Federico Pappalardo ◽  
Harikesh Subramanian ◽  
Giulia Ingoglia ◽  
Elena Conoscenti ◽  
...  
Keyword(s):  
Continuous Flow ◽  
Left Ventricular ◽  
Endocrine Function ◽  
Ventricular Assist Devices ◽  
Circulatory Support ◽  
Endocrine Dysfunction ◽  
Left Ventricular Assist Devices ◽  
Ventricular Assist ◽  
Assist Devices ◽  
Left Ventricular Assist

Heart failure (HF) remains a leading cause of morbidity, hospitalization, and mortality worldwide. Advancement of mechanical circulatory support technology has led to the use of continuous-flow left ventricular assist devices (LVADs), reducing hospitalizations, and improving quality of life and outcomes in advanced HF. Recent studies have highlighted how metabolic and endocrine dysfunction may be a consequence of, or associated with, HF, and may represent a novel (still neglected) therapeutic target in the treatment of HF. On the other hand, it is not clear whether LVAD support, may impact the outcome by also improving organ perfusion as well as improving the neuro-hormonal state of the patients, reducing the endocrine dysfunction. Moreover, endocrine function is likely a major determinant of human homeostasis, and is a key issue in the recovery from critical illness. Care of the endocrine function may contribute to improving cardiac contractility, immune function, as well as infection control, and rehabilitation during and after a LVAD placement. In this review, data on endocrine challenges in patients carrying an LVAD are gathered to highlight pathophysiological states relevant to this setting of patients, and to summarize the current therapeutic suggestions in the treatment of thyroid dysfunction, and vitamin D, erythropoietin and testosterone administration.

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