Effect of aging on ascending aortic flow measured by non-invasive MRI

Background: Limited invasive (electromagnetic) ascending aortic (AA) flow wave contour indicates impaired left ventricular (LV) function in the elderly. However, conventional non-invasive (Doppler) recordings have not shown similar aging change. Aim: To illustrate changes in AA flow and carotid pressure waves in an apparently normal cohort, using cardiac magnetic resonance imaging (CMRI). Methods: Fifty subjects (aged 21–70 years; 28 males) underwent velocity-encoded CMRI of the thoracic aorta using a 1.5T system (Signa, GEMS, Waukesha, USA). AA flow was measured non-invasively by subtracting simultaneous forward and backward flow velocity across the AA cross-section. DR⅓ was determined as ratio of difference in flow velocity between systolic peak and one-third of deceleration phase to peak flow velocity. Comparisons were made between young (≤50 years; n=30) and older subjects (>50 years; n=20). Results: Peak AA flow velocity decreased substantially (P50 years) (P