Aortic valve dynamics using a fluid structure interaction model – The physiology of opening and closing

Sundaram, Govinda Balan Kalyana; Balakrishnan, K.R.; Kumar, R. Suresh

doi:10.1016/j.jbiomech.2015.05.012

Cited by 15 publications

(11 citation statements)

References 20 publications

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“… 47 This approach is reported to be appropriate to capture the physiological valve opening-closure mechanics. 27 …”

Section: Methodsmentioning

confidence: 99%

“…In order to best simulate the closing dynamics, which involves the closing leakage produced by the reversal of the transvalvular pressure difference, during diastole the velocity profile was replaced by the application of a ventricular pressure waveform, establishing the pressure drop measured during the same phase in the in vitro test 47. This approach is reported to be appropriate to capture the physiological valve opening-closure mechanics 27…”

Section: Methodsmentioning

confidence: 99%

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Validation and Extension of a Fluid–Structure Interaction Model of the Healthy Aortic Valve

Tango

Salmonsmith

Ducci

et al. 2018

Cardiovasc Eng Tech

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PurposeThe understanding of the optimum function of the healthy aortic valve is essential in interpreting the effect of pathologies in the region, and in devising effective treatments to restore the physiological functions. Still, there is no consensus on the operating mechanism that regulates the valve opening and closing dynamics. The aim of this study is to develop a numerical model that can support a better comprehension of the valve function and serve as a reference to identify the changes produced by specific pathologies and treatments.MethodsA numerical model was developed and adapted to accurately replicate the conditions of a previous in vitro investigation into aortic valve dynamics, performed by means of particle image velocimetry (PIV). The resulting velocity fields of the two analyses were qualitatively and quantitatively compared to validate the numerical model. In order to simulate more physiological operating conditions, this was then modified to overcome the main limitations of the experimental setup, such as the presence of a supporting stent and the non-physiological properties of the fluid and vessels.ResultsThe velocity fields of the initial model resulted in good agreement with those obtained from the PIV, with similar flow structures and about 90% of the computed velocities after valve opening within the standard deviation of the equivalent velocity measurements of the in vitro model. Once the experimental limitations were removed from the model, the valve opening dynamics changed substantially, with the leaflets opening into the sinuses to a much greater extent, enlarging the effective orifice area by 11%, and reducing greatly the vortical structures previously observed in proximity of the Valsalva sinuses wall.ConclusionsThe study suggests a new operating mechanism for the healthy aortic valve leaflets considerably different from what reported in the literature to date and largely more efficient in terms of hydrodynamic performance. This work also confirms the crucial role that numerical approaches, complemented with experimental findings, can play in overcoming some of the limitations inherent in experimental techniques, supporting the full understanding of complex physiological phenomena.Electronic supplementary materialThe online version of this article (doi:10.1007/s13239-018-00391-1) contains supplementary material, which is available to authorized users.

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“… 47 This approach is reported to be appropriate to capture the physiological valve opening-closure mechanics. 27 …”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Validation and Extension of a Fluid–Structure Interaction Model of the Healthy Aortic Valve

Tango

Salmonsmith

Ducci

et al. 2018

Cardiovasc Eng Tech

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“…Since the initial aortic geometry was reconstructed at end-diastole, the intra-aortic pressure was about 80 mmHg [15] instead of a zero-pressure condition. The aorta stress-free configuration was achieved by extracting the resulting deformed mesh from mesh convergence simulation in which a pressure of 80 mmHg was imposed on the aortic external wall to offset the end-diastole pressure, as previously done in [16]. In order to simulate the blood flow and study the hydrodynamic effects, a fluid domain (Fig.…”

Section: Methodsmentioning

confidence: 99%

“…aortic wall) moved or deformed, maintaining the blood inside the aorta and vacuum outside. For simplification, the blood was assumed as Newtonian fluid [16] with a density of 1050 kg/m 3 , a dynamic viscosity set to 4.5e−3 Pa s and a bulk modulus of 2.5 GPa [16]. The relationship between blood pressure and volume (density) was described by a linear equation of state (detailed in Additional file 2: Appendix S2).…”

Section: Methodsmentioning

confidence: 99%

Investigating heartbeat-related in-plane motion and stress levels induced at the aortic root

et al. 2019

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Background The axial motion of aortic root (AR) due to ventricular traction was previously suggested to contribute to ascending aorta (AA) dissection by increasing its longitudinal stress, but AR in-plane motion effects on stresses have never been studied. The objective is to investigate the contribution of AR in-plane motion to AA stress levels. Methods The AR in-plane motion was assessed on magnetic resonance imagining data from 25 healthy volunteers as the movement of the AA section centroid. The measured movement was prescribed to the proximal AA end of an aortic finite element model to investigate its influences on aortic stresses. The finite element model was developed from a patient-specific geometry using LS-DYNA solver and validated against the aortic distensibility. Fluid–structure interaction (FSI) approach was also used to simulate blood hydrodynamic effects on aortic dilation and stresses. Results The AR in-plane motion was 5.5 ± 1.7 mm with the components of 3.1 ± 1.5 mm along the direction of proximal descending aorta (PDA) to AA centroid and 3.0 ± 1.3 mm perpendicularly under the PDA reference system. The AR axial motion elevated the longitudinal stress of proximal AA by 40% while the corresponding increase due to in-plane motion was always below 5%. The stresses at proximal AA resulted approximately 7% less in FSI simulation with blood flow. Conclusions The AR in-plane motion was comparable with the magnitude of axial motion. Neither axial nor in-plane motion could directly lead to AA dissection. It is necessary to consider the heterogeneous pressures related to blood hydrodynamics when studying aortic wall stress levels. Electronic supplementary material The online version of this article (10.1186/s12938-019-0632-7) contains supplementary material, which is available to authorized users.

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“…One conspicuous shortcoming of some earlier work in this area is the relatively simple material model of the valve leaflets [33, 51]. To enhance the realism of the BHV simulations for the design purpose, choosing an accurate material model is imperative as the material properties affect the mechanical behavior of the valve and may have an impact on the stress distributions and therefore the onset and incidence of leaflet tear and calcification [52].…”

Section: Materials Model For Bhv Leafletsmentioning

confidence: 99%

Computational methods for the aortic heart valve and its replacements

Zakerzadeh

Hsu

Sacks

2017

Expert Review of Medical Devices

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Replacement with a prosthetic device remains a major treatment option for the patients suffering from heart valve disease, with prevalence growing resulting from an ageing population. While the most popular replacement heart valve continues to be the bioprosthetic heart valve (BHV), its durability remains limited. There is thus a continued need to develop a general understanding of the underlying mechanisms limiting BHV durability to facilitate development of a more durable prosthesis. In this regard, computational models can play a pivotal role as they can evaluate our understanding of the underlying mechanisms and be used to optimize designs that may not always be intuitive. Areas covered: This review covers recent progress in computational models for the simulation of BHV, with a focus on aortic valve (AV) replacement. Recent contributions in valve geometry, leaflet material models, novel methods for numerical simulation, and applications to BHV optimization are discussed. This information should serve not only to infer reliable and dependable BHV function, but also to establish guidelines and insight for the design of future prosthetic valves by analyzing the influence of design, hemodynamics and tissue mechanics. Expert commentary: The paradigm of predictive modeling of heart valve prosthesis are becoming a reality which can simultaneously improve clinical outcomes and reduce costs. It can also lead to patient-specific valve design.

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Aortic valve dynamics using a fluid structure interaction model – The physiology of opening and closing

Cited by 15 publications

References 20 publications

Validation and Extension of a Fluid–Structure Interaction Model of the Healthy Aortic Valve

Validation and Extension of a Fluid–Structure Interaction Model of the Healthy Aortic Valve

Investigating heartbeat-related in-plane motion and stress levels induced at the aortic root

Computational methods for the aortic heart valve and its replacements

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