title: Local blood flow patterns in stented coronary bifurcations: an experimental and numerical study.
abstract: OBJECTIVE
  Despite the atheroprone environment of blood flow in coronary bifurcations, limited quantitative information is available on the hemodynamics occurring in these geometries, both before and after their treatment with endovascular stents. Previous studies have focused on computational fluid dynamics (CFD) analyses and have bypassed the challenges associated with experimentally representing the flow environment, providing no means for validation. This study analyzed steady flow conditions in 3 bifurcation angles and 4 different single- and double-stenting procedures, which are used clinically in coronary bifurcations.
  
  
  METHODS
  The numerical aspect of this study utilized geometries derived from CAD models (nonstented cases) and finite element simulations (stented cases). Digital particle image velocimetry (DPIV) testing was conducted within compliant bifurcating models for which an uncertainty analysis was performed at each measurement location for CFD validation purposes. Results were analyzed in terms of velocity magnitude contour maps and axial velocity profiles at several locations in the bifurcated vessels.
  
  
  CONCLUSIONS
  Qualitatively, the 2 approaches showed agreement in the bulk flow patterns. However, the velocity computed with CFD was outside the DPIV uncertainty estimates, which can be attributed to the intrinsic difference and modeling assumptions of the 2 approaches. The findings reveal that wider bifurcation angles and double-stenting procedures are both characterized by increased areas of low flow and recirculation. Additionally, inferior performance in terms of viscous and wall shear stresses was observed in double-stented cases.
authors.affiliation: School of Biomedical Engineering and Sciences, Virginia Tech, Blacksburg, Virginia - USA.
authors.forename: Jaime S
authors.initials: JS
authors.lastname: Raben
authors.affiliation: Laboratory of Biological Structure Mechanics (LaBS), Chemistry, Materials and Chemical Engineering Department Giulio Natta, Politecnico di Milano, Milan - Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Morlacchi
authors.affiliation: Department of Cardiovascular Sciences, Catholic University of the Sacred Heart, Rome - Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Burzotta
authors.affiliation: Laboratory of Biological Structure Mechanics (LaBS), Chemistry, Materials and Chemical Engineering Department Giulio Natta, Politecnico di Milano, Milan - Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Migliavacca
authors.affiliation: School of Mechanical Engineering, Purdue University, West Lafayette, Indiana - USA.
authors.forename: Pavlos P
authors.initials: PP
authors.lastname: Vlachos
mesh_terms: D003198:Computer Simulation; D003331:Coronary Vessels / Q000503:physiopathology*; D006801:Humans; D008955:Models, Cardiovascular; D012039:Regional Blood Flow / Q000502:physiology*; D012212:Rheology; D015607:Stents