title: Intravascular ultrasound study of angiographically mildly diseased coronary arteries.
abstract: OBJECTIVE
  We hypothesized that intravascular ultrasound may identify significant coronary artery narrowing in the mildly diseased coronary artery of patients with insignificant or one- or two-vessel coronary artery disease.
  
  
  BACKGROUND
  Necropsy studies have revealed that coronary angiography may underestimate stenosis severity in vessels that appear mildly diseased. Intravascular ultrasound has been shown to detect atherosclerotic changes in angiographically normal coronary arteries and to correlate better with histologic findings.
  
  
  METHODS
  In 20 patients, we performed intravascular ultrasound imaging (3.5F catheter, 30-MHz transducer) in 37 coronary arteries that were considered mildly diseased (<50% diameter narrowing) by qualitative angiography. The angiographic diagnosis was no significant coronary artery disease in eight patients, one-vessel disease in seven and two-vessel disease in five. Each vessel, except for the left main coronary artery, was divided into proximal, mid and distal segments. Percent area narrowing and minimal lumen diameter were subsequently quantified by both ultrasound and quantitative angiography.
  
  
  RESULTS
  Mean maximal arterial area narrowing by ultrasound in the 67 segments studied was 36 +/- 20% (range 0% to 80.2%) and 19 +/- 23% (range 0% to 82%) by quantitative angiography of these same segments (p < 0.001, paired t test). Mean minimal lumen diameter of the segment was 3.3 +/- 0.9 mm by ultrasound and 2.7 +/- 0.8 mm by quantitative angiography. In 10 patients there were 19 angiographically mildly diseased segments where the percent arterial area narrowing by ultrasound was > or = 50%. Intravascular ultrasound revealed that the more proximal (reference) segment had > 25% intimal thickening in 12 of the 19 underestimated segments. In six stenosed segments (32%), total vessel area increased compared with that of the adjacent proximal vessel segment because of compensatory dilation.
  
  
  CONCLUSIONS
  Intravascular ultrasound identifies potentially significant coronary artery disease in vessels that appear to be only mildly diseased by angiography.
authors.affiliation: Section of Cardiology, University of Nebraska Medical Center, Omaha 68198-2265.
authors.forename: T R
authors.initials: TR
authors.lastname: Porter
authors.forename: T
authors.initials: T
authors.lastname: Sears
authors.forename: F
authors.initials: F
authors.lastname: Xie
authors.forename: A
authors.initials: A
authors.lastname: Michels
authors.forename: J
authors.initials: J
authors.lastname: Mata
authors.forename: D
authors.initials: D
authors.lastname: Welsh
authors.forename: S
authors.initials: S
authors.lastname: Shurmur
mesh_terms: D003251:Constriction, Pathologic / Q000000981:diagnostic imaging / Q000453:epidemiology; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000453:epidemiology; D003331:Coronary Vessels / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D018084:Ultrasonography, Interventional