title: Estimation of maximum intraventricular pressure: a three-dimensional fluid-structure interaction model.
abstract: BACKGROUND
  The aim of this study was to propose a method to estimate the maximum pressure in the left ventricle (MPLV) for a healthy subject, based on cardiac outputs measured by echo-Doppler (non-invasive) and catheterization (invasive) techniques at rest and during exercise.
  
  
  METHODS
  Blood flow through aortic valve was measured by Doppler flow echocardiography. Aortic valve geometry was calculated by echocardiographic imaging. A Fluid-structure Interaction (FSI) simulation was performed, using an Arbitrary Lagrangian-Eulerian (ALE) mesh. Boundary conditions were defined as pressure loads on ventricular and aortic sides during ejection phase. The FSI simulation was used to determine a numerical relationship between the cardiac output to aortic diastolic and left ventricular pressures. This relationship enabled the prediction of pressure loads from cardiac outputs measured by invasive and non-invasive clinical methods.
  
  
  RESULTS
  Ventricular systolic pressure peak was calculated from cardiac output of Doppler, Fick oximetric and Thermodilution methods leading to a 22%, 18% and 24% increment throughout exercise, respectively. The mean gradients obtained from curves of ventricular systolic pressure based on Doppler, Fick oximetric and Thermodilution methods were 0.48, 0.41 and 0.56 mmHg/heart rate, respectively. Predicted Fick-MPLV differed by 4.7%, Thermodilution-MPLV by 30% and Doppler-MPLV by 12%, when compared to clinical reports.
  
  
  CONCLUSIONS
  Preliminary results from one subject show results that are in the range of literature values. The method needs to be validated by further testing, including independent measurements of intraventricular pressure. Since flow depends on the pressure loads, measuring more accurate intraventricular pressures helps to understand the cardiac flow dynamics for better clinical diagnosis. Furthermore, the method is non-invasive, safe, cheap and more practical. As clinical Fick-measured values have been known to be more accurate, our Fick-based prediction could be the most applicable.
authors.affiliation: Department of Biomechanics, Science and Research Branch, Islamic Azad University, Tehran, Iran. k.hasani@srbiau.ac.ir.
authors.forename: Hamidreza Ghasemi
authors.initials: HG
authors.lastname: Bahraseman
authors.forename: Kamran
authors.initials: K
authors.lastname: Hassani
authors.forename: Arezoo
authors.initials: A
authors.lastname: Khosravi
authors.forename: Mahdi
authors.initials: M
authors.lastname: Navidbakhsh
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Espino
authors.forename: Davood
authors.initials: D
authors.lastname: Kazemi-Saleh
authors.forename: Naser
authors.initials: N
authors.lastname: Fatourayee
mesh_terms: D000328:Adult; D002302:Cardiac Output / Q000502:physiology; D015444:Exercise / Q000502:physiology; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008954:Models, Biological; D010092:Oximetry; D012146:Rest / Q000502:physiology; D017725:Ventricular Pressure