title: Cardiovascular magnetic resonance-derived aortic distensibility: validation and observed regional differences in the elderly.
abstract: OBJECTIVE
  Applanation tonometry evaluation of pulse wave velocity is widely accepted as the 'gold standard' method for noninvasively assessing arterial stiffness. Newer noninvasive tools such as cardiovascular magnetic resonance can also evaluate arterial stiffness, but have not been validated. The aim of this study was to validate cardiovascular magnetic resonance-derived aortic distensibility with pulse wave velocity and to investigate age-related changes in regional aortic distensibility.
  
  
  METHODS
  Ten young (20-30 years) and ten old (60-70 years) patients underwent applanation tonometry assessment of pulse wave velocity. Cardiovascular magnetic resonance measurements of arterial stiffness were evaluated by aortic distensibility (10-3 mmHg-1) at three separate locations, the ascending aorta, proximal descending aorta and distal descending aorta.
  
  
  RESULTS
  Pulse wave velocity correlated strongly with aortic distensibility measurements at each site: ascending aorta R2 = 0.57, proximal descending aorta R2 = 0.60 and distal descending aorta R2 = 0.72. As expected, the old cohort had significantly increased aortic stiffness compared with the young cohort (P < 0.01). Post-hoc comparison showed an increase in proximal stiffness in the old cohort compared with the young cohort (P = 0.018).
  
  
  CONCLUSIONS
  Cardiovascular magnetic resonance-derived aortic distensibility is an accurate measure of arterial stiffness and can evaluate regional stiffness through the aorta. Furthermore, our results suggest that aortic stiffening may preferentially occur in the proximal aortic segments in the elderly.
authors.affiliation: Cardiovascular Research Centre, Royal Adelaide Hospital and Discipline of Medicine, University of Adelaide, Adelaide, South Australia, Australia.
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Nelson
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Worthley
authors.forename: James D
authors.initials: JD
authors.lastname: Cameron
authors.forename: Scott R
authors.initials: SR
authors.lastname: Willoughby
authors.forename: Cynthia
authors.initials: C
authors.lastname: Piantadosi
authors.forename: Angelo
authors.initials: A
authors.lastname: Carbone
authors.forename: Benjamin K
authors.initials: BK
authors.lastname: Dundon
authors.forename: Michael C
authors.initials: MC
authors.lastname: Leung
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Hope
authors.forename: Ian T
authors.initials: IT
authors.lastname: Meredith
authors.forename: Matthew I
authors.initials: MI
authors.lastname: Worthley