title: Extent and distribution of atherosclerotic plaque in relation to major coronary side-branches: an intravascular ultrasound study in vivo.
abstract: BACKGROUND
  The non-uniform extent and distribution of atherosclerotic plaque at bifurcations have been described by necropsy studies and they are related to local blood-flow disturbances. Systematic evaluation of plaque extent and distribution upstream and downstream of major coronary side-branches has not yet been evaluated in vivo.
  
  
  METHODS
  We used intravascular ultrasound imaging in 41 patients with atherosclerotic disease to study the region of 73 major coronary side-branches at 2 mm increments proximal and distal to the side-branch (657 images: 73 at origin of side-branch; 292 proximal; 292 distal). The maximum (MXT) and minimum (MINT) plaque thickness and the plaque burden percentage (% PB) were measured in all the segments. The angle of distribution of maximum plaque thickness with respect to the origin of the side-branch was determined in each cross-section and assigned to S1 when located on the semicircle in the direction of the origin of the side-branch and to S2 when located on the opposite wall.
  
  
  RESULTS
  The mean value of maximum plaque thickness and the plaque burden percentage were similar at the origin and in the two adjacent segments proximal and distal to the side-branch (1.0 +/- 0.48 mm, 1.06 +/- 0.48 mm and 0.98 +/- 0.48 mm; 45 +/- 19%, 46 +/- 19% and 44 +/- 18%). In distal sites of analysis, the plaque was more frequently eccentric in comparison to proximal sites (presence of an arc of plaque-free wall: 79% versus 62% in very distal and in very proximal sites respectively; p < 0.05). The prevalence of maximum plaque in S2 was higher at the origin (84%) and in adjacent distal segments (86%) as compared with the adjacent proximal segments (60%; p < 0.0001).
  
  
  CONCLUSIONS
  The distribution of plaque is influenced by the origin of a major coronary side-branch in patients with coronary atherosclerosis: in distal sites the location of maximum plaque is almost always eccentrically distributed on the wall opposite the take-off.
authors.affiliation: Thoraxcenter, University Hospital Rotterdam-Dijkzigt Erasmus University, The Netherlands.
authors.forename: M T
authors.initials: MT
authors.lastname: Mallus
authors.forename: M J
authors.initials: MJ
authors.lastname: Kutryk
authors.forename: F
authors.initials: F
authors.lastname: Prati
authors.forename: C
authors.initials: C
authors.lastname: von Birgelen
authors.forename: P J
authors.initials: PJ
authors.lastname: de Feyter
authors.forename: J R
authors.initials: JR
authors.lastname: Roelandt
authors.forename: P W
authors.initials: PW
authors.lastname: Serruys
mesh_terms: D000328:Adult; D000368:Aged; D003097:Collateral Circulation / Q000502:physiology; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003331:Coronary Vessels / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D014463:Ultrasonography