Regional aortic distensibility and its relationship with age and aortic stenosis: a computed tomography study

Aortic distensibility (AD) decreases with age and increased aortic stiffness is independently associated with adverse cardiovascular outcomes. The association of severe aortic stenosis (AS) with AD in different aortic regions has not been evaluated. Elderly subjects with severe AS and a cohort of patients without AS of similar age were studied. Proximal aortic cross-sectional-area changes during the cardiac cycle were determined using retrospective-ECG-gating on 128-detector row computed-tomography. Using oscillometric-brachial-blood-pressure measurements, the AD at the ascending-aorta (AA), proximal-descending-aorta (PDA) and distal-descending-aorta (DDA) was determined. Linear mixed effects modelling was used to determine the association of age and aortic stenosis on regional AD. 102 patients were evaluated: 36 AS patients (70-85 years), 24 AS patients (>85 years) and 42 patients without AS (9 patients <50 years, 20 patients between 51-70 years and 13 patients 70-85 years). When comparing patients 70-85 years, AA distensibility was significantly lower in those with AS compared to those without AS (0.9 ± 0.9 vs. 1.4 ± 1.1, P = 0.03) while there was no difference in the PDA (1.0 ± 1.1 vs. 1.0 ± 1.2, P = 0.26) and DDA (1.1 ± 1.2 vs. 1.2 ± 0.8, P = 0.97). In patients without AS, AD decreased with age in all aortic regions (P < 0.001). The AA in patients <50 years were the most distensible compared to other aortic regions. There is regional variation in aortic distensibility with aging. Patients with aortic stenosis demonstrated regional differences in aortic distensibility with lower distensibility demonstrated in the proximal ascending aorta compared to an age-matched cohort.