Cardiovascular magnetic resonance-derived aortic distensibility: validation and observed regional differences in the elderly

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 R-2=0.57, proximal descending aorta R-2=0.60 and distal descending aorta R-2=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). Conclusion 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. J Hypertens 27:535-542 (C) 2009 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.