title: Novel non-dimensional approach to comparison of wall shear stress distributions in coronary arteries of different groups of patients.
abstract: BACKGROUND
  Local wall shear stress (WSS) has an impact on local remodelling of the vessel wall. WSS in turn strongly depends on local geometry. Our aim was to characterize patterns of local wall shear stress associated with distinct types of remodelling in coronary arteries. Vessel size and flow rates are different between patients, however. To compare distribution patterns of WSS in analogy to fluid-dynamic modelling, non-dimensional WSS/area functions are calculated.
  
  
  METHODS
  Right coronary arteries from seven controls, five patients with coronary artery disease (CAD) and five patients with aneurysmatic CAD (AnCAD) were analyzed. Flow simulations were performed in three-dimensionally reconstructed coronary vessels from biplane angiographic projections. Local WSS was normalized as percentage of maximum value in a histogram (100 classes) and corresponding area was expressed as percentage of total area.
  
  
  RESULTS
  The normalized WSS distribution was characterized by a single peak with a large lower tie in controls, a loss of the single peak and a stochastic distribution in AnCAD and a narrowing of the lower tie in CAD. Correct classification of 16/17 coronary arteries was feasible by Fisher's discriminant functions based on median WSS, mean diameter, percentage of area with WSS <or=0.4 Pa and with WSS >or=15 Pa.
  
  
  CONCLUSIONS
  Normalized WSS distribution might be an efficient tool in comparing wall shear stress between different patient groups. Whether normalized WSS distribution curves are apt to grade severity of disease remains to be investigated.
authors.affiliation: German Heart Institute of Berlin, Berlin, Germany. Ewellnhofer@t-online.de
authors.forename: E
authors.initials: E
authors.lastname: Wellnhofer
authors.forename: L
authors.initials: L
authors.lastname: Goubergrits
authors.forename: U
authors.initials: U
authors.lastname: Kertzscher
authors.forename: K
authors.initials: K
authors.lastname: Affeld
authors.forename: E
authors.initials: E
authors.lastname: Fleck
mesh_terms: D000328:Adult; D000368:Aged; D003323:Coronary Aneurysm / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D017023:Coronary Angiography / Q000379:methods* / Q000592:standards; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D003331:Coronary Vessels / Q000502:physiology; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D013314:Stress, Mechanical; D020257:Ventricular Remodeling / Q000502:physiology