Heart-to-Brachium Pulse Wave Velocity as a Measure of Proximal Aortic Stiffness: MRI and Longitudinal Studies

BACKGROUND Stiffening of the proximal aorta is associated with heightened cardiovascular disease risks but can be quantified by limited methodologies (e.g., magnetic resonance imaging [MRI]). As an initial step to evaluate the emerging technique to assess proximal aortic stiffness via pulse wave velocity from the heart to the brachium (hbPWV), we determined the influences of aging on pulse wave velocity (PWV) and aortic hemodynamics. METHOD Using the cross-sectional and follow-up study designs, hbPWV was compared and evaluated in relation to other PWV in various arterial segments. Arterial path lengths were measured by the 3-dimensional arterial tracing of MRI. RESULTS In the cross-sectional study including 190 subjects (aged 19-79 years), hbPWV exhibited one of the largest age-related increases and a stronger correlation with age (r = 0.790) compared with the other measures of PWV including carotid-femoral PWV, brachial-ankle PWV, and PWV of muscular arteries (r = 0.445-0.688). In addition, hbPWV was correlated with aortic systolic blood pressure (BP) and augmentation index (r = 0.380 and 0.433, respectively) after controlling for brachial systolic BP. These results were confirmed by the 10-year follow-up study involving 84 individuals (53 years at baseline). The decadal changes in hbPWV were significantly correlated with the corresponding changes in several aortic hemodynamic variables (e.g., aortic systolic BP, augmentation pressure, and augmentation index) (r = 0.240-0.349). CONCLUSIONS The present findings indicate that hbPWV is a potential marker of proximal aortic stiffening that reflects age-related changes and aortic hemodynamics.