title: Normal distribution of an intravascular ultrasound index of vessel remodeling.
abstract: BACKGROUND
  As a consequence of plaque accumulation, coronary arteries may undergo both compensatory enlargement and paradoxical constriction. The aim of this study was to address the distribution of the different remodeling patterns in patients with obstructive coronary atherosclerosis.
  
  
  METHODS
  Eighty-seven non-branching segments of native coronary arteries with de novo, focal, non-ostial lesions were imaged at intravascular ultrasound (IVUS). Images were acquired with a motorized pull-back at a speed of 0.5 mm/s. The cross-sectional area (CSA) circumscribed by the external elastic membrane (EEM), the plaque + media complex and the lumen area were measured at its narrowest site (CSA with the minimal lumen area) and in the reference segment (average of proximal and distal reference cross-sections, defined as the most normal looking sites). The IVUS index of vessel remodeling (VRI) was calculated using the following formula: (narrowest site EEM CSA--reference EEM CSA)/reference EEM CSA*100. The index was tested for normality using the Kolmogorov-Smirnov goodness-of-fit test.
  
  
  RESULTS
  The frequency distribution of VRI was found to have a normal unimodal distribution (p = 0.60). VRI ranged from -60 to +164, with a mean of 9.3 +/- 28.0 and a median of 3.6. Frequency distribution of VRI slightly skewed towards right (skewness index 1.69). None of the analyzed clinical and morphological variables predicted the presence of compensatory enlargement as opposed to paradoxical constriction.
  
  
  CONCLUSIONS
  The frequency distribution of the vascular remodeling of de novo coronary lesions is unimodal. Therefore, compensatory enlargement and paradoxical constriction represent the extremes of a continuous spectrum.
authors.affiliation: Catheterization Laboratory, San Giovanni Hospital, Rome, Italy. f.prati@libero.it
authors.forename: Francesco
authors.initials: F
authors.lastname: Prati
authors.forename: Filippo
authors.initials: F
authors.lastname: Crea
authors.forename: Antonella
authors.initials: A
authors.lastname: Labellarte
authors.forename: Luigi
authors.initials: L
authors.lastname: Sommariva
authors.forename: Paola
authors.initials: P
authors.lastname: Marino
authors.forename: Eugenio
authors.initials: E
authors.lastname: Caradonna
authors.forename: Alessandro
authors.initials: A
authors.lastname: Manzoli
authors.forename: Alessandro
authors.initials: A
authors.lastname: Pappalardo
authors.forename: Alessandro
authors.initials: A
authors.lastname: Boccanelli
mesh_terms: D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D003331:Coronary Vessels / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016011:Normal Distribution; D018084:Ultrasonography, Interventional