title: Determinants of coronary artery compliance in subjects with and without angiographic coronary artery disease.
abstract: OBJECTIVE
  The goal of this study was to determine factors contributing to the biomechanical properties of coronary arteries in people with and without angiographic coronary artery disease (CAD).
  
  
  BACKGROUND
  The stiffness of the aorta is known to increase with increasing age and in the presence of CAD. However, little is known about the mechanics of coronary arteries, which may have important clinical consequences.
  
  
  METHODS
  Intravascular ultrasound was used to determine the mechanical properties of coronary arteries and plaque behavior in subjects with CAD (n = 38), those with chest pain but angiographically normal coronary arteries (N) (n = 9) and those early (<2 weeks) after cardiac transplant (T) (n = 14).
  
  
  RESULTS
  Coronary arteries dilated during systole in all groups, but cross-sectional compliance and distensibility were lowest in the proximal left anterior descending artery (LAD) in the subjects with CAD compared with the N and T groups (compliance: 1.2 +/- 0.2 vs. 1.7 +/- 0.5 and 2.7 +/- 0.6 x 10(-2) mm(2) mm Hg(-1) [mean +/- SEM] respectively, p < 0.02 CAD vs. T; distensibility: 0.8 +/- 0.2 vs. 1.7 +/- 0.5 and 1.7 +/- 0.3 x 10(-3) mm Hg(-1), p < 0.05 CAD vs. T). There was extensive plaque in the CAD group, and plaque was also present in the N group, but minimal atheroma was present in the T group. Plaque cross-sectional area diminished significantly during systole in both the LAD and circumflex arteries. Absolute changes were: 0.50 +/- 0.30, 0.33 +/- 0.11 and 0.68 +/- 0.13 mm(2) in the proximal LAD, distal LAD and proximal circumflex arteries, respectively. In subjects with atheroma, there was a significant correlation between cross-sectional compliance and plaque compression at all sites, and plaque compression was a significant determinant of cross-sectional compliance at both proximal sites in multiple regression analyses with age, mean arterial pressure and extent of plaque as the other independent variables.
  
  
  CONCLUSIONS
  A major determinant of the systolic increase in coronary luminal area in patients with atheroma is a reduction in plaque cross-sectional area during systole.
authors.affiliation: Alfred and Baker Medical unit, Alfred Hospital and Baker Medical Research Institute, Melbourne, Australia.
authors.forename: James A
authors.initials: JA
authors.lastname: Shaw
authors.forename: Bronwyn A
authors.initials: BA
authors.lastname: Kingwell
authors.forename: Anthony S
authors.initials: AS
authors.lastname: Walton
authors.forename: James D
authors.initials: JD
authors.lastname: Cameron
authors.forename: Prakash
authors.initials: P
authors.lastname: Pillay
authors.forename: Christoph D
authors.initials: CD
authors.lastname: Gatzka
authors.forename: Anthony M
authors.initials: AM
authors.lastname: Dart
mesh_terms: D000328:Adult; D015906:Angioplasty, Balloon, Coronary; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000503:physiopathology* / Q000628:therapy; D003331:Coronary Vessels / Q000502:physiology*; D005260:Female; D016027:Heart Transplantation; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000503:physiopathology / Q000628:therapy; D012016:Reference Values; D013599:Systole / Q000502:physiology; D018084:Ultrasonography, Interventional; D014655:Vascular Resistance / Q000502:physiology*