title: Effect of exercise on blood flow through the aortic valve: a combined clinical and numerical study.
abstract: The aim of this study was to measure the cardiac output and stroke volume for a healthy subject by coupling an echocardiogram Doppler (echo-Doppler) method with a fluid-structure interaction (FSI) simulation at rest and during exercise. Blood flow through aortic valve was measured by Doppler flow echocardiography. Aortic valve geometry was calculated by echocardiographic imaging. An FSI simulation was performed, using an arbitrary Lagrangian-Eulerian mesh. Boundary conditions were defined by pressure loads on ventricular and aortic sides. Pressure loads applied brachial pressures with (stage 1) and without (stage 2) differences between brachial, central and left ventricular pressures. FSI results for cardiac output were 15.4% lower than Doppler results for stage 1 (r = 0.999). This difference increased to 22.3% for stage 2. FSI results for stroke volume were undervalued by 15.3% when compared to Doppler results at stage 1 and 26.2% at stage 2 (r = 0.94). The predicted mean backflow of blood was 4.6%. Our results show that numerical methods can be combined with clinical measurements to provide good estimates of patient-specific cardiac output and stroke volume at different heart rates.
authors.affiliation: a Department of Biomechanics , Science and Research Branch, Islamic Azad University , Tehran , Iran.
authors.forename: Hamidreza Ghasemi
authors.initials: HG
authors.lastname: Bahraseman
authors.forename: Kamran
authors.initials: K
authors.lastname: Hassani
authors.forename: Mahdi
authors.initials: M
authors.lastname: Navidbakhsh
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Espino
authors.forename: Zahra Alizadeh
authors.initials: ZA
authors.lastname: Sani
authors.forename: Nasser
authors.initials: N
authors.lastname: Fatouraee
mesh_terms: D000328:Adult; D001021:Aortic Valve / Q000000981:diagnostic imaging / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology; D002302:Cardiac Output / Q000502:physiology; D003326:Coronary Circulation / Q000502:physiology*; D015150:Echocardiography, Doppler; D055119:Elastic Modulus; D015444:Exercise / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology; D006439:Hemodynamics; D018056:Hemorheology / Q000502:physiology; D006801:Humans; D008297:Male; D009716:Numerical Analysis, Computer-Assisted; D012044:Regression Analysis; D013318:Stroke Volume / Q000502:physiology; D013599:Systole / Q000502:physiology
keywords: cardiac output; echo-Doppler flow; fluid–structure interaction; stroke volume