Global Aortic Pulse Wave Velocity is Unchanged in Bicuspid Aortopathy With Normal Valve Function but Elevated in Patients With Aortic Valve Stenosis: Insights From a 4D Flow MRI Study of 597 Subjects

Figures

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  FIGURE 1. Study cohort. The cohort for this study was composed of patients with aortopathy and bicuspid aortic valve or tricuspid aortic valve and healthy subjects with tricuspid valves. Patients with bicuspid aortic valve and a range of aortic valve stenosis were included. AS = aortic valve stenosis; AV = aortic valve; BAV = bicuspid aortic valve; TAV = tricuspid aortic valve.

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  FIGURE 2. Global pulse‐wave velocity estimation. The computation flow for global PWV estimation included pre‐processing of 4D flow MRI, calculation of through‐plane flow through cross‐sections along the length of the aorta, and cross‐correlation of flow curves and linear fits of the time delays along the length; global PWV was estimated from the fits for all planes. PWV = pulse wave velocity; 4D = four‐dimensional.

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  FIGURE 3. Relations of pulse wave velocity, age, and aortic dimension. Linear correlations between PWV, age, and mAAo are shown (a–c) for the healthy control subjects and the four patient groups (top to bottom). Pearson correlation coefficient (r) values are shown along with a solid line fit for correlations showing statistical significance (P < 0.05) or a dashed line for correlations without statistical significance. PWV = pulse wave velocity; mAAo = median ascending aortic diameter.

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  FIGURE 4. Global pulse wave velocity value distributions across subject groups by age range. Distribution of global PWV in 10‐year age ranges are shown for healthy subjects (green), TAV patients with AAo dilatation (yellow), BAV patients with AAo dilatation and no/trace AS (purple), mild AS (dark blue), and moderate/severe AS (light blue). Hypothesis‐testing P values are annotated for inter‐group comparisons with significance level 0.01 (Bonferroni correction for five groups). PWV = pulse wave velocity; TAV = tricuspid aortic valve; AAo = ascending aorta/aortic; BAV = bicuspid aortic valve; AS = aortic valve stenosis.

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  FIGURE 5. Inter‐observer comparison for PWV calculation. Segmentations from multiple observers for a subgroup of subjects were collected (left), and the automated PWV calculation method (center) was applied to each segmentation. The inter‐observer comparison for PWV (right) is shown with limits of agreement (right, dashed lines) and intra‐class correlation coefficients (right). PWV = pulse wave velocity; ICC = intra‐class correlation coefficient.