Fluid structure interaction modelling of aortic valve stenosis: Effects of valve calcification on coronary artery flow and aortic root hemodynamics

Kivi, Araz R.; Sedaghatizadeh, Nima; Cazzolato, B.; Zander, Anthony C.; Roberts-Thomson, Ross; Nelson, Adam; Arjomandi, Maziar

doi:10.1016/j.cmpb.2020.105647

Cited by 21 publications

(8 citation statements)

References 37 publications

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“…The values of C, A 1−6 for each of the valve types used in the current study were obtained from previous studies [30][31][32]. To simulate the effect of increased leaflet stiffness due to severe calcification for SAV, we assumed a 10-fold increase in the value of C with a uniform distribution based on previous studies [23,24]. The structural solver solves for displacement (figure 1f ), and Newmark algorithm was used to compute leaflet velocity and acceleration [34].…”

Section: Patient-specific Fsi Modellingmentioning

confidence: 99%

“…Combined with a highly nonlinear and instantaneous valve deformation, simulation time for an FSI model at physiological Re could be prohibitively long for pre-operative planning of AV interventions. Such challenges can either force us to use a coarse mesh [21] or use other artificial methods such as higher-than-physiological viscosity [22], truncate the computational domain into conduit-type models [17–20,22] or restrict the analysis to two-dimension [23,24], hence potentially compromising physiological accuracy. However, the implications of the AV function extend far beyond the vicinity of the leaflets [27].…”

Section: Introductionmentioning

confidence: 99%

“…The current state-of-the-art in FSI-based AV studies use a conduit-type inlet and outlet to represent ventricular inlet and aortic outlet, respectively [17][18][19][20][21][22]. Although these studies have provided insights into the AV dynamics and associated blood flow in the immediate vicinity of the valve leaflets [17][18][19][20][21][22][23][24], application of a conduit-type inlet to represent LV wall motion-induced change in LV pressure may affect the overall accuracy of the computation. Additionally, it may be a challenge to impose patient-specific boundary conditions using models with simplified conduit-type ventricular inlets and, hence, may not be most suitable for patient-specific planning and evaluation of AV interventions.Peak systolic flow in the aorta is known to be in the laminar-to-turbulent transitional flow regime and can go up to a turbulent Reynolds number (Re) of 10 000 under disease conditions [25].…”

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confidence: 99%

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Improving transcatheter aortic valve interventional predictability via fluid–structure interaction modelling using patient-specific anatomy

Govindarajan¹,

Kolanjiyil

Johnson³

et al. 2022

R. Soc. open sci.

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Transcatheter aortic valve replacement (TAVR) is now a standard treatment for high-surgical-risk patients with severe aortic valve stenosis. TAVR is being explored for broader indications including degenerated bioprosthetic valves, bicuspid valves and for aortic valve (AV) insufficiency. It is, however, challenging to predict whether the chosen valve size, design or its orientation would produce the most-optimal haemodynamics in the patient. Here, we present a novel patient-specific evaluation framework to realistically predict the patient's AV performance with a high-fidelity fluid–structure interaction analysis that included the patient's left ventricle and ascending aorta (AAo). We retrospectively evaluated the pre- and post-TAVR dynamics of a patient who underwent a 23 mm TAVR and evaluated against the patient's virtually de-calcified AV serving as a hypothetical benchmark. Our model predictions were consistent with clinical data. Stenosed AV produced a turbulent flow during peak-systole, while aortic flow with TAVR and de-calcified AV were both in the laminar-to-turbulent transitional regime with an estimated fivefold reduction in viscous dissipation. For TAVR, dissipation was highest during early systole when valve deformation was the greatest, suggesting that an efficient valve opening may reduce energy loss. Our study demonstrates that such patient-specific modelling frameworks can be used to improve predictability and in the planning of AV interventions.

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Section: Patient-specific Fsi Modellingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Improving transcatheter aortic valve interventional predictability via fluid–structure interaction modelling using patient-specific anatomy

Govindarajan¹,

Kolanjiyil

Johnson³

et al. 2022

R. Soc. open sci.

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“…The maximum WSS in an elastic vessel is significantly lower than that in a vessel with rigid walls (29,30). By setting the blood vessel wall as elastic, not only will the simulation results be closer to the real situation in the human body, but the data will also be more accurate (31,32). In patient-specific twoway FSI analysis, the hemodynamic parameters of AORL are closer to the real physiological state in humans.…”

Section: Introductionmentioning

confidence: 95%

Transient numerical simulation of the right coronary artery originating from the left sinus and the effect of its acute take-off angle on hemodynamics

Cong

Zhao

Dai

et al. 2021

Quant Imaging Med Surg

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Background: An anomalous origin of the right coronary artery from the left coronary artery sinus is usually characterized by an acute take-off angle. Most affected patients have no clinical symptoms; however, some patients have decreased blood flow into the right coronary artery during exercise, which can lead to symptoms such as myocardial ischemia. Most researchers who have studied an anomalous origin of the right coronary artery from the left coronary artery sinus have done so through clinical cases. In this study, we used numerical simulation to evaluate the hemodynamics of this condition and the effect of an acute take-off angle on hemodynamic parameters. We expect that the results of this study will help in further understanding the clinical symptoms of this anomaly and the hemodynamic impact of an acute take-off angle.Methods: Three-dimensional models were reconstructed based on the computed tomography images from 16 patients with a normal right coronary artery and 26 patients with an anomalous origin of the right coronary artery from the left coronary artery sinus. A numerical simulation of a two-way fluid-structure interaction was executed with ANSYS Workbench software. The blood was assumed to be an incompressible Newtonian fluid, and the vessel was assumed to be an isotropic, linear elastic material. Hemodynamic parameters and the effect of an acute take-off angle were statistically analyzed.Results: During the systolic period, the wall pressure in the right coronary artery was significantly reduced in patients with an anomalous origin of the right coronary artery (t =1.32 s, P=0.0001; t =1.34-1.46 s, P<0.0001). The wall shear stress in the abnormal group was higher at the beginning of the systolic period (t =1.24 s, P=0.0473; t =1.26 s, P=0.0193; t =1.28 s, P=0.0441). The acute take-off angle was smaller in patients with clinical symptoms (27.81°±4.406°) than in patients without clinical symptoms (31.86°±2.789°; P=0.017). In the symptomatic group, pressure was negatively correlated with the acute take-off angle (P=0.0185-0.0341, r=−0.459 to −0.4167). Conclusions:This study shows that an anomalous origin of the right coronary artery from the left coronary artery sinus causes changes in hemodynamic parameters, and that an acute take-off angle in patients with this anomaly is associated with terminal ischemia of the right coronary artery.

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“…Vahidkhah et al [42] compared blood residence times in the coronary and non-coronary leaflets after a TAVR procedure and determined similar residence times for all the leaflets. Kivi et al [20] performed two dimensional fluid-structure interaction (FSI) simulations with leaflets of varying stiffness. A common finding in CFD simulations is the presence of stagnant regions in the aortic sinus, in which blood clots are thought to form.…”

Section: Introductionmentioning

confidence: 99%

A Model of Fluid-Structure and Biochemical Interactions for Applications to Subclinical Leaflet Thrombosis

Barrett¹,

Brown²,

Smith³

et al. 2022

Preprint

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Subclinical leaflet thrombosis (SLT) is a potentially serious complication of aortic valve replacement with a bioprosthetic valve in which blood clots form on the replacement valve. SLT is associated with increased risk of transient ischemic attacks and strokes and can progress to clinical leaflet thrombosis. SLT following aortic valve replacement also may be related to subsequent structural valve deterioration, which can impair the durability of the valve replacement. Because of the difficulty in clinical imaging of SLT, models are needed to determine the mechanisms of SLT and could eventually predict which patients will develop SLT. To this end, we develop methods to simulate leaflet thrombosis that combine fluid-structure interaction and a simplified thrombosis model that allows for deposition along the moving leaflets. Additionally, this model can be adapted to model deposition or absorption along other moving boundaries. We present both convergence results and quantify the model's ability to realize changes in stroke volume and pressures. These new approaches are an important advancement in thrombosis modeling in that it incorporates both adhesion to the surface of the leaflets and feedback to the fluid-structure interaction.

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Fluid structure interaction modelling of aortic valve stenosis: Effects of valve calcification on coronary artery flow and aortic root hemodynamics

Cited by 21 publications

References 37 publications

Improving transcatheter aortic valve interventional predictability via fluid–structure interaction modelling using patient-specific anatomy

Improving transcatheter aortic valve interventional predictability via fluid–structure interaction modelling using patient-specific anatomy

Transient numerical simulation of the right coronary artery originating from the left sinus and the effect of its acute take-off angle on hemodynamics

A Model of Fluid-Structure and Biochemical Interactions for Applications to Subclinical Leaflet Thrombosis

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