Circumferential strain and strain rates of the descending aorta as novel measures of aortic stiffness and wall mechanics from standard cardiac MRI.

Abstract

During standard cardiovascular magnetic resonance (CMR) the horizontal long-axis cine image (i.e., 4-chamber) is captured which includes a cross-section of the descending aorta. The aortic cross-section can be used to assess aortic stiffness (distensibility; ∆area/pressure) or circumferential strain (percentage vascular deformation). We examined whether descending aortic strain from traditional CMR is sensitive to age- and disease-related (heart failure with preserved ejection fraction; HFpEF) arteriosclerosis. We recruited 83 participants into three groups: (1) 34 young individuals (age: 22 ± 3 years; body mass index (BMI): 24.3 ± 2.8 kg/m²); (2) 19 older individuals (age: 69 ± 5 years; BMI: 26.9 ± 4.7 kg/m²) and (3) 26 patients with HFpEF (age: 69 ± 6 years; BMI: 35.8 ± 6.1 kg/m²). All participants were studied in the same 3 T scanner (Phillips, Achieva). Descending aortic cross-sectional area and circumferential strain were measured using cvi⁴² software. Blood pressure was measured via a brachial oscillometric cuff. Data were compared via ANOVA. All data are reported as means ± standard deviation. Compared to the young group (71 ± 5 mmHg), mean arterial pressure was higher in the older (83 ± 9 mmHg, P < 0.001) and HFpEF groups (86 ± 10 mmHg, P < 0.001). Minimum and maximum aortic areas were greater in the older and HFpEF groups (both, P < 0.01). Peak descending aortic strain (young: 11.4% ± 2.2%; older: 4.8% ± 1.6%; HFpEF 3.8% ± 1.6%) and absolute distension were lower (all, P < 0.02) in the older and HFpEF groups compared to the young. Peak descending aortic strain and strain rates are sensitive to age and may provide a novel assessment of arterial stiffness for longitudinal studies that utilize or have utilized CMR.