Patient-specific bicuspid valve dynamics: Overview of methods and challenges

Chandran, K. B.; Vigmostad, Sarah C.

doi:10.1016/j.jbiomech.2012.10.038

Cited by 29 publications

(27 citation statements)

References 38 publications

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“…FEM models provide valuable insights in increased stress exerted on the bicuspid valve compared to the tricuspid valve (35,36). CFD has the ability to simulate aortic blood flow in BAV disease, and the main outcomes of these studies correspond to the results of this study, i.e.…”

Section: Discussionmentioning

confidence: 99%

Characterization of Abnormal Wall Shear Stress Using 4D Flow MRI in Human Bicuspid Aortopathy

et al. 2014

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There exists considerable controversy surrounding the timing and extent of aortic resection for patients with BAV disease. Since abnormal wall shear stress (WSS) is potentially associated with tissue remodeling in BAV-related aortopathy, we propose a methodology that creates patient-specific ‘heat maps’ of abnormal WSS, based on 4D flow MRI. The heat maps were created by detecting outlier measurements from a volumetric 3D map of ensemble-averaged WSS in healthy controls. 4D flow MRI was performed in 13 BAV patients, referred for aortic resection and 10 age-matched controls. Systolic WSS was calculated from this data, and an ensemble-average and standard deviation (SD) WSS map of the controls was created. Regions of the individual WSS maps of the BAV patients that showed a higher WSS than the mean+1.96SD of the ensemble-average control WSS map were highlighted. Elevated WSS was found on the greater ascending aorta (35% ± 15 of the surface area), which correlated significantly with peak systolic velocity (R2=0.5, P=0.01) and showed good agreement with the resected aortic regions. This novel approach to characterize regional aortic WSS may allow clinicians to gain unique insights regarding the heterogeneous expression of aortopathy and may be leveraged to guide patient-specific resection strategies for aorta repair.

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Section: Discussionmentioning

confidence: 99%

Characterization of Abnormal Wall Shear Stress Using 4D Flow MRI in Human Bicuspid Aortopathy

et al. 2014

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“…The results suggest that not only the severity of the COA should be considered to evaluate the mentioned risks but also the presence and the severity of the BAV; (3) The findings of this study can help hypothesizing in part the mechanisms behind the aneurysm development in the aorta before or after a surgical repair of the COA. The specific alterations in the flow field and induced complications resulting from the sole presence of a BAV can be found in the literature [57]–[64]. The development of an aneurysm involves the interplay between the mechanical forces applied to the artery and the biological processes occurring at the cellular level [65].…”

Section: Discussionmentioning

confidence: 99%

Fluid Dynamics of Coarctation of the Aorta and Effect of Bicuspid Aortic Valve

2013

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Up to 80% of patients with coarctation of the aorta (COA) have a bicuspid aortic valve (BAV). Patients with COA and BAV have elevated risks of aortic complications despite successful surgical repair. The development of such complications involves the interplay between the mechanical forces applied on the artery and the biological processes occurring at the cellular level. The focus of this study is on hemodynamic modifications induced in the aorta in the presence of a COA and a BAV. For this purpose, numerical investigations and magnetic resonance imaging measurements were conducted with different configurations: (1) normal: normal aorta and normal aortic valve; (2) isolated COA: aorta with COA (75% reduction by area) and normal aortic valve; (3) complex COA: aorta with the same severity of COA (75% reduction by area) and BAV. The results show that the coexistence of COA and BAV significantly alters blood flow in the aorta with a significant increase in the maximal velocity, secondary flow, pressure loss, time-averaged wall shear stress and oscillatory shear index downstream of the COA. These findings can contribute to a better understanding of why patients with complex COA have adverse outcome even following a successful surgery.

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“…Most image-based modeling strategies start by extracting static (not moving) geometries of interest from images, creating a CFD model from those geometries, and then imposing flow and/or normal traction (pressure) boundary conditions to the model inlets and outlets (Steinman 2002; Taylor and Steinman 2010; Chandran et al 2011). A few studies have also extracted dynamic cardiac geometries from images (Schenkel et al 2009; Mihalef et al 2011; Chandran and Vigmostad 2013). Boundary conditions used for these CFD models depend on data availability, and range from data measured in the same subject, to average or estimated data based on previous studies.…”

Section: Introductionmentioning

confidence: 99%

4D subject-specific inverse modeling of the chick embryonic heart outflow tract hemodynamics

Goenezen

Chivukula

Midgett

et al. 2015

Biomech Model Mechanobiol

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Blood flow plays a critical role in regulating embryonic cardiac growth and development, with altered flow leading to congenital heart disease. Progress in the field, however, is hindered by a lack of quantification of hemodynamic conditions in the developing heart. In this study, we present a methodology to quantify blood flow dynamics in the embryonic heart using subject-specific computational fluid dynamics (CFD) models. While the methodology is general, we focused on a model of the chick embryonic heart outflow tract (OFT), which distally connects the heart to the arterial system, and is the region of origin of many congenital cardiac defects. Using structural and Doppler velocity data collected from optical coherence tomography (OCT), we generated 4D (3D + time) embryo-specific CFD models of the heart OFT. To replicate the blood flow dynamics over time during the cardiac cycle, we developed an iterative inverse-method optimization algorithm, which determines the CFD model boundary conditions such that differences between computed velocities and measured velocities at one point within the OFT lumen are minimized. Results from our developed CFD model agree with previously measured hemodynamics in the OFT. Further, computed velocities and measured velocities differ by less than 15% at locations that were not used in the optimization, validating the model. The presented methodology can be used in quantifications of embryonic cardiac hemodynamics under normal and altered blood flow conditions, enabling an in depth quantitative study of how blood flow influences cardiac development.

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Patient-specific bicuspid valve dynamics: Overview of methods and challenges

Cited by 29 publications

References 38 publications

Characterization of Abnormal Wall Shear Stress Using 4D Flow MRI in Human Bicuspid Aortopathy

Characterization of Abnormal Wall Shear Stress Using 4D Flow MRI in Human Bicuspid Aortopathy

Fluid Dynamics of Coarctation of the Aorta and Effect of Bicuspid Aortic Valve

4D subject-specific inverse modeling of the chick embryonic heart outflow tract hemodynamics

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