Aortic flow is associated with aging and exercise capacity

Figures

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  Figure 1. Illustration of two-dimensional aortic flow parameter calculations. (A) Segmentation of aorta for whole cardiac cycle in two-dimensional phase-contrast magnetic resonance imaging. The borders were segmented on the reconstructed magnitude images and copied onto the phase images; (B) Aortic flow curve with illustrations of peak systole, late systole, systole, and diastole phase; (C) Flow displacement curve; (D) Flow displacement rotational angle curve; (E) Flow displacement rotational speed curve; (F) Flow reversal ratio curve; (G) Three-dimensional aortic arch length between ascending and descending aorta by reconstructing the aortic arch using bright-blood sequence, and pulse wave velocity by the half-maximum method. The grey areas denoted flow displacement ≤12% and were excluded in the calculations of rotational angle and rotational speed. The unit of the x-axis in each figure is the frame number.

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  Figure 2. Scatterplots with regression lines, 95% confidence lines, and heat maps between flow parameters with age (left panel) and peak oxygen uptake (right panel) for average flow displacement during late systole (first row), systole (second row), and diastole (third row), and systolic flow reversal ratio (last row).

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  Figure 3. Example aortic flow curve (A), flow displacement curve (B), and flow reversal ratio (C) in a 65 year old male healthy subject with PVO2 = 44 mL/kg/min and a 67 year old female healthy subject with PVO2 = 11 mL/kg/min. The unit of the x-axis in each figure is the frame number.

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  Figure 4. Differences in two-dimensional aortic flow parameters according to the subgroups based on peak oxygen uptake. (A) Average systolic flow displacement; (B) average late systolic flow displacement; (C) average diastolic flow displacement; (D) systolic flow reversal ratio. *P < 0.05 compared with PVO2 > 20 mL/kg/min. Error bars denote mean ± standard deviation.

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  Figure 5. Incremental value of left ventricular ejection fraction, aortic forward flow index, and average flow displacement during systole for discriminating healthy subjects with PVO2 ≤ 14 mL/kg/min.

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  Figure 6. Bland–Altman plots for aortic blood flow components. (A) Bland–Altman analysis of intraobserver repeated measurements; (B) Bland–Altman analysis of interobserver repeated measurements. From left to right, top to bottom: average flow displacement during systole, late systole and diastole, peak systolic flow displacement, rotational angle, rotational speed, systolic forward flow, systolic flow reversal ratio, and pulse wave velocity.

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  Figure 7. Central illustration demonstrating cardiovascular magnetic resonance-derived physiological model for estimating peak oxygen uptake non-invasively without exercise.