title: Impact of Side Branch Modeling on Computation of Endothelial Shear Stress in Coronary Artery Disease: Coronary Tree Reconstruction by Fusion of 3D Angiography and OCT.
abstract: BACKGROUND
  Computational fluid dynamics allow virtual evaluation of coronary physiology and shear stress (SS). Most studies hitherto assumed the vessel as a single conduit without accounting for the flow through side branches.
  
  
  OBJECTIVE
  This study sought to develop a new approach to reconstruct coronary geometry that also computes outgoing flow through side branches in hemodynamic and biomechanical calculations, using fusion of optical coherence tomography (OCT) and 3-dimensional (3D) angiography.
  
  
  METHODS
  Twenty-one patients enrolled in the DOCTOR (Does Optical Coherence Tomography Optimize Revascularization) fusion study underwent OCT and 3D-angiography of the target vessel (9 left anterior descending, 2 left circumflex, 10 right coronary artery). Coronary 3D reconstruction was performed by fusion of OCT and angiography, creating a true anatomical tree model (TM) including the side branches, and a traditional single-conduit model (SCM) disregarding the side branches.
  
  
  RESULTS
  The distal coronary pressure to aortic pressure (Pd/Pa) ratio was significantly higher in TMs than in SCMs (0.904 vs. 0.842; p < 0.0001). Agreement between TM and SCM in identifying patients with a Pd/Pa ratio ≤0.80 under basal flow conditions was only k = 0.417 (p = 0.019). Average SS was 4.64 Pascal lower in TMs than in SCMs (p < 0.0001), with marked differences in the point-per-point comparison, ranging from -60.71 to 7.47 Pascal.
  
  
  CONCLUSIONS
  True anatomical TMs that take into account the flow through side branches are feasible for accurate hemodynamic and biomechanical calculations. Traditional SCMs underestimate Pd/Pa and are inaccurate for regional SS estimation. Implementation of TMs might improve the accuracy of SS and virtual fractional flow reserve calculations, thus improving the consistency of biomechanical studies.
authors.affiliation: Division of Image Processing, Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands.
authors.forename: Yingguang
authors.initials: Y
authors.lastname: Li
authors.affiliation: Interventional Cardiology Department, Charité Medical University - Campus Benjamin Franklin, Berlin, Germany.
authors.forename: Juan Luis
authors.initials: JL
authors.lastname: Gutiérrez-Chico
authors.affiliation: Department of Cardiology, Aarhus University Hospital, Skejby, Aarhus, Denmark.
authors.forename: Niels R
authors.initials: NR
authors.lastname: Holm
authors.affiliation: Department of Radiology, Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Wenjie
authors.initials: W
authors.lastname: Yang
authors.affiliation: Department of Cardiology, Aarhus University Hospital, Skejby, Aarhus, Denmark.
authors.forename: Lasse
authors.initials: L
authors.lastname: Hebsgaard
authors.affiliation: Department of Cardiology, Aarhus University Hospital, Skejby, Aarhus, Denmark.
authors.forename: Evald H
authors.initials: EH
authors.lastname: Christiansen
authors.affiliation: Department of Cardiology, Aarhus University Hospital, Skejby, Aarhus, Denmark.
authors.forename: Michael
authors.initials: M
authors.lastname: Mæng
authors.affiliation: Department of Cardiology, Aarhus University Hospital, Skejby, Aarhus, Denmark.
authors.forename: Jens F
authors.initials: JF
authors.lastname: Lassen
authors.affiliation: Department of Radiology, Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Fuhua
authors.initials: F
authors.lastname: Yan
authors.affiliation: Division of Image Processing, Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands.
authors.forename: Johan H C
authors.initials: JH
authors.lastname: Reiber
authors.affiliation: Biomedical Instrument Institute, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China. Electronic address: sxtu@sjtu.edu.cn.
authors.forename: Shengxian
authors.initials: S
authors.lastname: Tu
mesh_terms: D000368:Aged; D001696:Biomechanical Phenomena; D017023:Coronary Angiography; D003327:Coronary Disease / Q000503:physiopathology*; D003331:Coronary Vessels / Q000503:physiopathology*; D004727:Endothelium / Q000502:physiology*; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D057446:Hydrodynamics; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D013314:Stress, Mechanical; D041623:Tomography, Optical Coherence
keywords: computational fluid dynamics; fractional flow reserve; optical coherence tomography; shear stress