A non-discrete method for computation of residence time in fluid mechanics simulations

Esmaily, Mahdi; Hsia, Tain‐Yen; Marsden, Alison L.

doi:10.1063/1.4819142

Cited by 58 publications

(61 citation statements)

References 46 publications

(55 reference statements)

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“…Using a Lagrangian approach, T R evolution can be described by the advection equation with unit forcing,

\partial_{t} T_{R} + \nabla \cdot false({\vec{υ}}_{inc} T_{R} false) = 1,

where

{\vec{υ}}_{inc}

is the velocity field. Previous works have considered a similar equation with a non-zero mass diffusivity term (Esmaily-Moghadam et al 2013, Jozsa & Kramer 2000, Mangual et al 2012), but we note that the self-diffusivity of blood is negligible compared to its advective fluxes inside the LV (Bermejo et al 2015, Tarbell 2003). The full derivation of equation (1) can be found in Appendix I.…”

Section: Methodsmentioning

confidence: 90%

A clinical method for mapping and quantifying blood stasis in the left ventricle

Rossini

Martínez‐Legazpi

et al. 2016

Journal of Biomechanics

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In patients at risk of intraventricular thrombosis, the benefits of chronic anticoagulation therapy need to be balanced with the pro-hemorrhagic effects of therapy. Blood stasis in the cardiac chambers is a recognized risk factor for intracardiac thrombosis and potential cardiogenic embolic events. In this work, we present a novel flow image-based method to assess the location and extent of intraventricular stasis regions inside the left ventricle (LV) by digital processing flow-velocity images obtained either by phase-contrast magnetic resonance (PCMR) or 2D color-Doppler velocimetry (echo-CDV). This approach is based on quantifying the distribution of the blood Residence Time (TR) from time-resolved blood velocity fields in the LV. We tested the new method in illustrative examples of normal hearts, patients with dilated cardiomyopathy and one patient before and after the implantation of a left ventricular assist device (LVAD). The method allowed us to assess in-vivo the location and extent of the stasis regions in the LV. Original metrics were developed to integrate flow properties into simple scalars suitable for a robust and personalized assessment of the risk of thrombosis. From a clinical perspective, this work introduces the new paradigm that quantitative flow dynamics can provide the basis to obtain subclinical markers of intraventricular thrombosis risk. The early prediction of LV blood stasis may result in decrease strokes by appropriate use of anticoagulant therapy for the purpose of primary and secondary prevention. It may also have a significant impact on LVAD device design and operation set-up.

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“…Using a Lagrangian approach, T R evolution can be described by the advection equation with unit forcing,

\partial_{t} T_{R} + \nabla \cdot false({\vec{υ}}_{inc} T_{R} false) = 1,

where

{\vec{υ}}_{inc}

Section: Methodsmentioning

confidence: 90%

A clinical method for mapping and quantifying blood stasis in the left ventricle

Rossini

Martínez‐Legazpi

et al. 2016

Journal of Biomechanics

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“…This work incorporates recent advances in simulation technology, including lumped parameter boundary conditions (Lagana et al 2002), increasing anatomical realism, particle tracking (Shadden and Taylor 2008), and non-discrete residence time computations (Esmaily-Moghadam et al 2013). In addition, we also make a direct comparison between simulations with rigid and deformable walls to quantify the resulting differences in wall shear stress (WSS) (Figueroa et al 2006).…”

Section: Introductionmentioning

confidence: 99%

Thrombotic risk stratification using computational modeling in patients with coronary artery aneurysms following Kawasaki disease

Sengupta

Kahn

Kung

et al. 2014

Biomech Model Mechanobiol

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Kawasaki disease (KD) is the leading cause of acquired heart disease in children and can result in life-threatening coronary artery aneurysms in up to 25 % of patients. These aneurysms put patients at risk of thrombus formation, myocardial infarction, and sudden death. Clinicians must therefore decide which patients should be treated with anticoagulant medication, and/or surgical or percutaneous intervention. Current recommendations regarding initiation of anticoagulant therapy are based on anatomy alone with historical data suggesting that patients with aneurysms ≥8 mm are at greatest risk of thrombosis. Given the multitude of variables that influence thrombus formation, we postulated that hemodynamic data derived from patient-specific simulations would more accurately predict risk of thrombosis than maximum diameter alone. Patient-specific blood flow simulations were performed on five KD patients with aneurysms and one KD patient with normal coronary arteries. Key hemodynamic and geometric parameters, including wall shear stress, particle residence time, and shape indices, were extracted from the models and simulations and compared with clinical outcomes. Preliminary fluid structure interaction simulations with radial expansion were performed, revealing modest differences in wall shear stress compared to the rigid wall case. Simulations provide compelling evidence that hemodynamic parameters may be a more accurate predictor of thrombotic risk than aneurysm diameter alone and motivate the need for follow-up studies with a larger cohort. These results suggest that a clinical index incorporating hemodynamic information be used in the future to select patients for anticoagulant therapy.

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“…Preliminary studies simulating flow conditions in KD have recently shown that these hemodynamic factors may be better predictors of thrombotic risk than aneurysm diameter alone. 4,32 However, validation of simulations in realistic coronary aneurysm geometries with physiologic flow conditions has not been previously performed. Validation is key to supporting the continued development of CFD tools in support of KD patient management.…”

Section: Discussionmentioning

confidence: 99%

In Vitro Validation of Patient-Specific Hemodynamic Simulations in Coronary Aneurysms Caused by Kawasaki Disease

Kung

Kahn

Burns

et al. 2014

Cardiovasc Eng Tech

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To perform experimental validation of computational fluid dynamics (CFD) applied to patient specific coronary aneurysm anatomy of Kawasaki disease. We quantified hemodynamics in a patient-specific coronary artery aneurysm physical phantom under physiologic rest and exercise flow conditions. Using phase contrast MRI (PCMRI), we acquired 3-component flow velocity at two slice locations in the aneurysms. We then performed numerical simulations with the same geometry and inflow conditions, and performed qualitative and quantitative comparisons of velocities between experimental measurements and simulation results. We observed excellent qualitative agreement in flow pattern features. The quantitative spatially and temporally varying differences in velocity between PCMRI and CFD were proportional to the flow velocity. As a result, the percent discrepancy between simulation and experiment was relatively constant regardless of flow velocity variations. Through 1D and 2D quantitative comparisons, we found a 5–17% difference between measured and simulated velocities. Additional analysis assessed wall shear stress differences between deformable and rigid wall simulations. This study demonstrated that CFD produced good qualitative and quantitative predictions of velocities in a realistic coronary aneurysm anatomy under physiological flow conditions. The results provide insights on factors that may influence the level of agreement, and a set of in vitro experimental data that can be used by others to compare against CFD simulation results. The findings of this study increase confidence in the use of CFD for investigating hemodynamics in the specialized anatomy of coronary aneurysms. This provides a basis for future hemodynamics studies in patient-specific models of Kawasaki disease.

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A non-discrete method for computation of residence time in fluid mechanics simulations

Cited by 58 publications

References 46 publications

A clinical method for mapping and quantifying blood stasis in the left ventricle

A clinical method for mapping and quantifying blood stasis in the left ventricle

Thrombotic risk stratification using computational modeling in patients with coronary artery aneurysms following Kawasaki disease

In Vitro Validation of Patient-Specific Hemodynamic Simulations in Coronary Aneurysms Caused by Kawasaki Disease

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