title: Intravascular ultrasound assessment of regional aortic wall stiffness, distensibility, and compliance in patients with coarctation of the aorta.
abstract: BACKGROUND
  Impaired aortic pulsatility has been demonstrated by angiography in children and in studies of experimental animals with coarctation of the aorta.
  
  
  OBJECTIVE
  The purpose of this study was to assess regional aortic stiffness, distensibility, and compliance before and after balloon dilation in patients with coarctation of the aorta.
  
  
  RESULTS
  Intravascular ultrasound examination was performed in 13 pediatric patients with the diagnosis of coarctation of the aorta to yield aortic diameter. Area transverse sections at both systolic and diastolic period were measured at three aortic levels: the proximal, distal, and coarctation segments. Balloon dilation was also performed in eight of 13 patients. By using pressures measured in the same areas, an aortic stiffness index (beta) was calculated as In(Ps/Pd)/(Ds-Dd), where In is natural logarithm, Ps is systolic pressure, Pd is diastolic pressure, Ds is systolic diameter, and Dd is diastolic diameter. Aortic distensibility and an estimation of aortic compliance were also calculated. The beta stiffness index of the coarctation and the proximal segments of the aorta were significantly greater than that of the distal segment of the aorta (p < 0.01). The aortic wall stiffness beta index did not acutely change after successful balloon dilation, but the distensibility and compliance of distal aorta were nonetheless significantly decreased after balloon dilation (p < 0.01, p < 0.05) as a function of changes of pulsatility of flow.
  
  
  CONCLUSIONS
  Abnormal proximal aortic stiffness may be a strong contributing factor that promotes the genesis of hypertension in patients with coarctation even after successful repair or balloon angioplasty.
authors.affiliation: Clinical Care Center for Congenital Heart Disease, Oregon Health Sciences University, Portland 97201-3098, USA.
authors.forename: J
authors.initials: J
authors.lastname: Xu
authors.forename: T
authors.initials: T
authors.lastname: Shiota
authors.forename: R
authors.initials: R
authors.lastname: Omoto
authors.forename: X
authors.initials: X
authors.lastname: Zhou
authors.forename: S
authors.initials: S
authors.lastname: Kyo
authors.forename: M
authors.initials: M
authors.lastname: Ishii
authors.forename: M J
authors.initials: MJ
authors.lastname: Rice
authors.forename: D J
authors.initials: DJ
authors.lastname: Sahn
mesh_terms: D000293:Adolescent; D000792:Angiography; D000800:Angioplasty, Balloon; D001011:Aorta / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology; D001017:Aortic Coarctation / Q000150:complications / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology / Q000628:therapy; D001794:Blood Pressure; D002648:Child; D002675:Child, Preschool; D003187:Compliance; D003971:Diastole; D004548:Elasticity; D005260:Female; D006801:Humans; D006973:Hypertension / Q000209:etiology; D007223:Infant; D016014:Linear Models; D008297:Male; D011673:Pulsatile Flow; D013599:Systole; D018084:Ultrasonography, Interventional / Q000295:instrumentation / Q000379:methods