Fluid structure interaction modelling of aortic valve stenosis: Effects of valve calcification on coronary artery flow and aortic root hemodynamics. (November 2020)

• Record Type: Journal Article
• Authors: Kivi, Araz R.; Sedaghatizadeh, Nima; Cazzolato, Benjamin S.; Zander, Anthony C.; Roberts-Thomson, Ross; Nelson, Adam J.; Arjomandi, Maziar
• Is Part Of: Computer methods and programs in biomedicine. Volume 196(2020)
• Publication Date: 2020-11
• Subjects: Aortic valve stenosis -- Aortic valve leaflets -- Coronary artery hemodynamics -- Calcification -- Transvalvular pressure gradient -- Valve orifice diameter -- Wall shear stress -- Fluid structure interaction; Medicine -- Computer programs -- Periodicals; Biology -- Computer programs -- Periodicals; Computers -- Periodicals; Medicine -- Periodicals; Médecine -- Logiciels -- Périodiques; Biologie -- Logiciels -- Périodiques; Biology -- Computer programs; Medicine -- Computer programs; Periodicals; Electronic journals; 610.28
• DOI: 10.1016/j.cmpb.2020.105647
• Languages: English
• ISSNs: 0169-2607

Abstract

Highlights: The effect of aortic valve stenosis on hemodynamic parameters inside aortic root including transvalvular pressure gradient, valve orifice diameter, maximum jet velocity along the aortic valve have been investigated. The effect of calcification of the aortic valve on wall shear stress on leaflets has been studied. The results showed that the difference between the wall shear stress of the fibrosa and ventricularis layers can be a reason for calcification progression. The flow features inside sinuses because of the aortic valve stenosis have been investigated. The results revealed that calcification changes the flow behaviour in sinuses and this could be a reason for calcium deposition on the leaflets. The influence of aortic valve stenosis on coronary flow and its hemodynamics has been investigated. Calcification significantly changes the hemodynamic parameters inside coronary arteries and might be a factor for initiation of the coronary artery diseases. Abstract: Background and objective: Coronary artery diseases and aortic valve stenosis are two of the main causes of mortality and morbidity worldwide. Stenosis of the aortic valve develops due to calcium deposition on the aortic valve leaflets during the cardiac cycle. Clinical investigations have demonstrated that aortic valve stenosis not only affects hemodynamic parameters inside the aortic root but also has a significant influence on the coronary artery hemodynamics and leads to the initiation of coronary artery disease. The aim of this study is to investigate the effect of calcification of the aortic valve on the variation of hemodynamic parameters in the aortic root and coronary arteries in order to find potential locations for initiation of the coronary stenoses. Methods: Fluid structure interaction modelling methodology was used to simulate aortic valve hemodynamics in the presence of coronary artery flow. A 2-D model of the aortic valve leaflets was developed in ANSYS Fluent based on the available echocardiography images in literature. The k - ω SST turbulence model was utilised to model the turbulent flow downstream of the leaflets. Results: The effects of calcification of the aortic valve on aortic root hemodynamics including transvalvular pressure gradient, valve orifice dimeter, vorticity magnitude in the sinuses and wall shear stress on the ventricularis and fibrosa layers of the leaflets were studied. Results revealed that the transvalvular pressure gradient increases from 792 Pa (∼ 6 mmHg) for a healthy aortic valve to 2885 Pa (∼ 22 mmHg) for a severely calcified one. Furthermore, the influence of the calcification of the aortic valve leaflets on the velocity profile and the wall shear stress in the coronary arteries was investigated and used for identification of potential locations of initiation of the coronary stenoses. Obtained results show that the maximum velocity inside the coronary arteries at early diastole decreases from 1 m/s for the healthy valve to 0.45 m/s for the severely calcified case. Conclusions: Calcification significantly decreases the wall shear stress of the coronary arteries. This reduction in the wall shear stress can be a main reason for initiation of the coronary atherosclerosis process and eventually results in coronary stenoses.