title: Atherosclerosis in angiographically "normal" coronary artery reference segments: an intravascular ultrasound study with clinical correlations.
abstract: OBJECTIVE
  This study evaluated the magnitude, patterns and clinical correlates of atherosclerosis in angiographically "normal" reference segments in patients undergoing transcatheter therapy for symptomatic coronary artery disease.
  
  
  BACKGROUND
  Pathologic studies indicate that the extent of coronary atherosclerosis is underestimated by visual analysis of angiographically normal coronary artery segments. Intravascular ultrasound allows detailed, high quality cross-sectional imaging of the coronary arteries in vivo.
  
  
  METHODS
  Intravascular ultrasound was used to study angiographically normal coronary artery reference segments in 884 patients evaluated for transcatheter therapy for symptomatic native coronary artery disease. The reference segment was the most visually normal intravascular ultrasound cross section within 10 mm proximal to the target lesion but distal to any major side branch. Results are presented as mean value +/- 1 SD.
  
  
  RESULTS
  Only 60 (6.8%) of 884 angiographically normal reference segments were normal by intravascular ultrasound. Reference segment percent cross-sectional narrowing measured 51 +/- 13% and correlated poorly with the target lesion percent cross-sectional narrowing (r = 0.166, p < 0.0001). Reference segments contained less calcific and dense fibrotic plaque and proportionately more soft plaque elements. Independent predictors of reference segment percent cross-sectional narrowing were male gender, patient age, diabetes mellitus, hypercholesterolemia and presence of multivessel disease. Independent predictors of reference segment calcification were patient age and serum creatinine levels. Reference segment percent cross-sectional narrowing in 723 patients undergoing transcatheter therapy was similar to that in patients studied for diagnostic purposes; however, reference segment arc of calcium was greater in treated patients (43 +/- 81 vs. 25 +/- 57, p = 0.015). Reference segment disease was not an independent predictor of subsequent angiographic restenosis or clinical events within 12 months of follow-up.
  
  
  CONCLUSIONS
  Atherosclerosis is ubiquitous in angiographically normal coronary artery reference segments. Reference segment disease parallels the severity of target lesion disease and is associated with many of the conventional risk factors for coronary artery disease. Because of its sensitivity in detecting atherosclerosis in angiographically normal reference segments, intravascular ultrasound should enhance the study of risk factors for atherosclerosis and the results of therapies to control disease progression.
authors.affiliation: Intravascular Ultrasound Imaging and Cardiac Catheterization Laboratories, Washington Hospital Center, Washington, DC 20010, USA.
authors.forename: G S
authors.initials: GS
authors.lastname: Mintz
authors.forename: J A
authors.initials: JA
authors.lastname: Painter
authors.forename: A D
authors.initials: AD
authors.lastname: Pichard
authors.forename: K M
authors.initials: KM
authors.lastname: Kent
authors.forename: L F
authors.initials: LF
authors.lastname: Satler
authors.forename: J J
authors.initials: JJ
authors.lastname: Popma
authors.forename: Y C
authors.initials: YC
authors.lastname: Chuang
authors.forename: T A
authors.initials: TA
authors.lastname: Bucher
authors.forename: L E
authors.initials: LE
authors.lastname: Sokolowicz
authors.forename: M B
authors.initials: MB
authors.lastname: Leon
mesh_terms: D000367:Age Factors; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000628:therapy; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000473:pathology; D005069:Evaluation Studies as Topic; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012008:Recurrence; D012044:Regression Analysis; D012307:Risk Factors; D012680:Sensitivity and Specificity; D012737:Sex Factors; D013997:Time Factors; D018084:Ultrasonography, Interventional