title: Combining numerical and clinical methods to assess aortic valve hemodynamics during exercise.
abstract: Computational simulations have the potential to aid understanding of cardiovascular hemodynamics under physiological conditions, including exercise. Therefore, blood hemodynamic parameters during different heart rates, rest and exercise have been investigated, using a numerical method. A model was developed for a healthy subject. Using geometrical data acquired by echo-Doppler, a two-dimensional model of the chamber of aortic sinus valsalva and aortic root was created. Systolic ventricular and aortic pressures were applied as boundary conditions computationally. These pressures were the initial physical conditions applied to the model to predict valve deformation and changes in hemodynamics. They were the clinically measured brachial pressures plus differences between brachial, central and left ventricular pressures. Echocardiographic imaging was also used to acquire different ejection times, necessary for pressure waveform equations of blood flow during exercise. A fluid-structure interaction simulation was performed, using an arbitrary Lagrangian-Eulerian mesh. During exercise, peak vorticity increased by 14.8%, peak shear rate by 15.8%, peak cell Reynolds number by 20%, peak leaflet tip velocity increased by 47% and the blood velocity increased by 3% through the leaflets, whereas full opening time decreased by 11%. Our results show that numerical methods can be combined with clinical measurements to provide good estimates of patient-specific hemodynamics at different heart rates.
authors: Department of Biomechanics, Science and Research Branch, Islamic Azad University, Tehran, Iran.
authors: Hg
authors: H
authors: Bahraseman
authors: Department of Biomechanics, Science and Research Branch, Islamic Azad University, Tehran, Iran.
authors: K
authors: K
authors: Hassani
authors: Atherosclerosis Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran arekhosravi@yahoo.com.
authors: A
authors: A
authors: Khosravi
authors: Department of Mechanical Engineering, Iran University of Science and Technology, Tehran, Iran.
authors: M
authors: M
authors: Navidbakhsh
authors: School of Mechanical Engineering, University of Birmingham, UK.
authors: Dm
authors: D
authors: Espino
authors: Department of Biomedical Engineering, Amirkabir University, Tehran, Iran.
authors: N
authors: N
authors: Fatouraee
authors: Atherosclerosis Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran.
authors: D
authors: D
authors: Kazemi-Saleh
keywords: echo-Doppler flow; fluid-structure interaction; hemodynamics; natural aortic valve