Comparison of platelet activation through hinge vs bulk flow in bileaflet mechanical heart valves

Hedayat, Mohammadali; Borazjani, Iman

doi:10.1016/j.jbiomech.2018.12.003

Cited by 40 publications

(23 citation statements)

References 43 publications

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“…60 Multimedia views: https://doi.org/10.1063/1.5081451.1; https://doi.org/10.1063/1.5081451. 2 This method has been validated against experimental and benchmark solutions 33,34,37 and has been applied to a variety of problems such as cardiovascular flows, 15,23,[38][39][40][41] aquatic swimming, 36,42 rheology, 43 among others. More specifically, the NKM method with immersed boundaries has been validated for different flows by Asgharzadeh and Borazjani.…”

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confidence: 99%

A non-dimensional parameter for classification of the flow in intracranial aneurysms. II. Patient-specific geometries

et al. 2019

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A simple parameter, called the Aneurysm number (An) which is defined as the ratio of transport to vortex time scales, has been shown to classify the flow mode in simplified aneurysm geometries. Our objective is to test the hypothesis that An can classify the flow in patient-specific intracranial aneurysms (IA). Therefore, the definition of this parameter is extended to anatomic geometries by using hydraulic diameter and the length of expansion area in the approximate direction of the flow. The hypothesis is tested using image-based flow simulations in five sidewall and four bifurcation geometries, i.e., if An ≲ 1 (shorter transport time scale), then the fluid is transported across the neck before the vortex could be formed, creating a quasi-stationary shear layer (cavity mode). By contrast, if An ≳ 1 (shorter vortex time scale), a vortex is formed. The results show that if An switches from An ≲ 1 to An ≳ 1, then the flow mode switches from the cavity mode to the vortex mode. However, if An does not switch, then the IAs stay in the same mode. It is also shown that IAs in the cavity mode have significantly lower An, temporal fluctuations of wall shear stress and oscillatory shear index (OSI) compared to the vortex mode (p < 0.01). In addition, OSI correlates with An in each flow mode and with pulsatility index in each IA. This suggests An to be a viable hemodynamic parameter which can be easily calculated without the need for detailed flow measurements/ simulations.

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confidence: 99%

A non-dimensional parameter for classification of the flow in intracranial aneurysms. II. Patient-specific geometries

et al. 2019

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“…Thus, the hinge mechanism was simplified as previously modeled by . This simplification was justified by the fact that the platelet activation generated by the hinge domain was less than 10% of the total activation of the bulk flow …”

Section: Methodsmentioning

confidence: 99%

“…The hinge mechanism of BMHV was also simplified and the valve was mainly modeled as moving leaflets and housing to maintain an acceptable level of mesh skewness throughout the simulations. This was justified by the fact that the platelet activation generated by the hinge domain was found to be less than 10% of the total activation of the bulk flow which is relatively very small. The blood flow was simulated as laminar flow because turbulence occurs only for a very brief period in a cardiac cycle as has been considered by Refs …”

Section: Limitations Of the Current Studymentioning

confidence: 99%

Numerical investigation on the effect of bileaflet mechanical heart valve's implantation tilting angle and aortic root geometry on intermittent regurgitation and platelet activation

et al. 2019

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Platelet activation induced by shear stresses and non-physiological flow field generated by bileaflet mechanical heart valves (BMHVs) leads to thromboembolism, which can cause fatal consequences. One of the causes of platelet activation could be intermittent regurgitation, which arises due to asynchronous movement and rebound of BMHV leaflets during the valve closing phase. In this numerical study, the effect of intermittent regurgitation on the platelet activation potential of BMHVs was quantified by modeling a BMHV in the straight and anatomic aorta at implantation tilt angles 0°, 5°, 10°, and 20°. A fully implicit Arbitrary Lagrangian-Eulerian-based Fluid-Structure Interaction formulation was adopted with blood modeled as a multiphase, non-Newtonian fluid. Results showed that the intermittent regurgitation and consequently the platelet activation level increases with the increasing implantation tilt of BMHV. For the straight aorta, the leaflet of the 20° tilted BMHV underwent a rebound of approximately 20° after initially closing, whereas the leaflet of the 10°, 5°, and 0° tilted BMHVs underwent a rebound of 8.5°, 3°, and 0°, respectively. For the anatomic aorta, the leaflet of the 20° tilted BMHV underwent a rebound of approximately 24° after initially closing, whereas the leaflet of the 10°, 5°, and 0° tilted BMHVs underwent a rebound of 14°, 10°, and 7°, respectively. For all the implantation orientations of BMHVs, intermittent regurgitation and platelet activation were always higher in the anatomic aorta than in the straight aorta. The study concludes that the pivot axis of BMHV must be implanted parallel to the aortic root's curvature to minimize intermittent regurgitation and platelet activation. K E Y W O R D Saortic root geometry, bileaflet mechanical heart valve, implantation tilting angle, intermittent regurgitation, platelet activation

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“…SAS can be also categorized as fixed and dynamic SAS, based on the obstacle’s dimensions, and whether stable or varied [ 7 , 8 ]. In most cases, the dimensions of the obstructive orifice are static from beat to beat, which is referred to as fixed SAS, while in the dynamic type the severity of obstruction is changed by heart rate, and also usually alters as the systole progresses [ 9 , 10 ].…”

Section: Introductionmentioning

confidence: 99%

Hemodynamic Performance of Dysfunctional Prosthetic Heart Valve with the Concomitant Presence of Subaortic Stenosis: In Silico Study

et al. 2020

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The prosthetic heart valve is vulnerable to dysfunction after surgery, thus a frequent assessment is required. Doppler electrocardiography and its quantitative parameters are commonly used to assess the performance of the prosthetic heart valves and provide detailed information on the interaction between the heart chambers and related prosthetic valves, allowing early detection of complications. However, in the case of the presence of subaortic stenosis, the accuracy of Doppler has not been fully investigated in previous studies and guidelines. Therefore, it is important to evaluate the accuracy of the parameters in such cases to get early detection, and a proper treatment plan for the patient, at the right time. In the current study, a CFD simulation was performed for the blood flow through a Bileaflet Mechanical Heart Valve (BMHV) with concomitant obstruction in the Left Ventricle Outflow Tract (LVOT). The current study explores the impact of the presence of the subaortic on flow patterns. It also investigates the accuracy of (BMHV) evaluation using Doppler parameters, as proposed in the American Society of Echocardiography (ASE) guidelines.

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Comparison of platelet activation through hinge vs bulk flow in bileaflet mechanical heart valves

Cited by 40 publications

References 43 publications

A non-dimensional parameter for classification of the flow in intracranial aneurysms. II. Patient-specific geometries

A non-dimensional parameter for classification of the flow in intracranial aneurysms. II. Patient-specific geometries

Numerical investigation on the effect of bileaflet mechanical heart valve's implantation tilting angle and aortic root geometry on intermittent regurgitation and platelet activation

Hemodynamic Performance of Dysfunctional Prosthetic Heart Valve with the Concomitant Presence of Subaortic Stenosis: In Silico Study

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