title: Hemodynamic numerical simulations of the disturbance due to intracoronary flow measurements by a Doppler guide wire.
abstract: BACKGROUND
  Since hemodynamics plays a key role in the development and evolution of cardiovascular pathologies, physician's decision must be based on proper monitoring of relevant physiological flow quantities.
  
  
  METHODS
  A numerical analysis of the error introduced by an intravascular Doppler guide wire on the peak velocity measurements has been carried out. The effect of probe misalignment (±10°) with respect to the vessel axis was investigated. Numerical simulations were performed on a realistic 3D geometry, reconstructed from coronary angiography images. Furthermore, instead of using Poiseuille or Womersley approximations, the unsteady pulsatile inlet boundary condition has been calculated from experimental peak-velocity measurements inside the vessel through a new approach based on an iterative Newton's algorithm.
  
  
  RESULTS
  The results show that the presence of the guide modifies significantly both the maximum velocity and the peak position in the section plane; the difference is between 6 and 17 % of the maximum measured velocity depending on the distance from the probe tip and the instantaneous vessel flow rate. Furthermore, a misalignment of the probe may lead to a wrong estimation of the peak velocity with an error up to 10 % depending on the probe orientation angle.
  
  
  CONCLUSIONS
  The Doppler probe does affect the maximum velocity and its position during intravascular Doppler measurements. Moreover, the Doppler-probe-wire sampling volume at 5.2 and 10 mm far from the probe tip is not sufficient to prevent its influence on the measurement. This should be taken into account in clinical practice by physicians during intravascular Doppler quantification. The new numerical approach used in this work could potentially be helpful in future numerical simulations to set plausible inlet boundary conditions.
authors.affiliation: Laboratoire de Médecine Expérimentale (ULB 222 Unit), Route de Gozée 706, 6110, Montigny-le-Tilleul, Belgium. Kamil.Chodzynski@umons.ac.be.|Faculté Polytechnique de Mons-Service Fluides-Machines, Université de Mons, 53, rue du Joncquois, 7000, Mons, Belgium. Kamil.Chodzynski@umons.ac.be.
authors.forename: Kamil J
authors.initials: KJ
authors.lastname: Chodzyński
authors.affiliation: Faculté Polytechnique de Mons-Service Fluides-Machines, Université de Mons, 53, rue du Joncquois, 7000, Mons, Belgium.
authors.forename: Simone
authors.initials: S
authors.lastname: Gremmo
authors.affiliation: Service de Neuroradiologie Hôpital Gui de Chauliac, 80 Avenue Augustin Flich, 34295, Montpellier cedex 05, France.
authors.forename: Omer F
authors.initials: OF
authors.lastname: Eker
authors.affiliation: Service of Cardiology, CHU Charleroi, Boulevard Zoé Drion, 16000, Charleroi, Belgium.
authors.forename: Jacques
authors.initials: J
authors.lastname: Lalmand
authors.affiliation: Service of Cardiology, CHU Charleroi, Boulevard Zoé Drion, 16000, Charleroi, Belgium.
authors.forename: Adel
authors.initials: A
authors.lastname: Aminian
authors.affiliation: Laboratoire de Médecine Expérimentale (ULB 222 Unit), Route de Gozée 706, 6110, Montigny-le-Tilleul, Belgium.
authors.forename: Daniel Ribeiro
authors.initials: DR
authors.lastname: de Sousa
authors.affiliation: Laboratoire de Médecine Expérimentale (ULB 222 Unit), Route de Gozée 706, 6110, Montigny-le-Tilleul, Belgium.
authors.forename: Karim Zouaoui
authors.initials: KZ
authors.lastname: Boudjeltia
authors.affiliation: Faculté Polytechnique de Mons-Service Fluides-Machines, Université de Mons, 53, rue du Joncquois, 7000, Mons, Belgium.
authors.forename: Grégory
authors.initials: G
authors.lastname: Coussement
mesh_terms: D000465:Algorithms; D017023:Coronary Angiography; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000502:physiology*; D006439:Hemodynamics; D057446:Hydrodynamics; D021621:Imaging, Three-Dimensional; D008955:Models, Cardiovascular; D063177:Pulse Wave Analysis / Q000295:instrumentation*
keywords: Doppler guide wire; Flow disturbance; Numerical simulations; Unsteady pulsatile inlet boundary condition