Four-dimensional flow MRI demonstrated that patients with bicuspid aortic valves had higher average peak velocity (1.3 vs 1.2 m/s; P<0.016) compared to tricuspid valves despite similar dimensions.
Cross-Sectional (n=165)
Does 4D flow MRI identify morphological and hemodynamic differences between patients with bicuspid aortic valves, tricuspid aortic valves with dilated aortas, and healthy controls?
4D flow MRI demonstrates that patients with bicuspid aortic valves have altered aortic hemodynamics compared to those with tricuspid aortic valves, even when aortic dimensions are similar.
Absolute Event Rate: 1.3% vs 1.2%
p-value: p=<0.016
AIMS: Four-dimensional (4D) flow magnetic resonance imaging (MRI) was employed for the simultaneous assessment of morphometry and flow parameters along the thoracic aorta to investigate associations between flow, age, aorta diameter, and aortic valve morphology. METHODS AND RESULTS: One hundred and sixty-five subjects, 65 controls, 50 patients with bicuspid aortic valve (BAV), and 50 patients with a dilated aorta, and a tricuspid aortic valve (TAV) underwent 4D flow MRI. Following 3D segmentation of the aorta, a vessel centreline was calculated and used to extract aorta diameter, peak systolic velocity, and normalized systolic flow displacement. Validation of 4D flow MRI-based morphometric measurements compared with manual diameter measurements from standard contrast-enhanced MR angiography in 20 controls showed good agreement (mean difference = 0.4 mm, limits of agreement = ±1.31 mm) except at the sinus of valsalva. BAV showed significant differences in average peak velocity (PV; P < 0.016) compared with TAV and controls between the left ventricle outflow tract to sino-tubular junction (BAV: 1.3 ± 0.3 m/s; TAV: 1.2 ± 0.2 m/s; controls: 1.0 ± 0.1 m/s) and the ascending aorta for average normalized flow displacement (BAV: 0.11 ± 0.02; TAV: 0.09 ± 0.02; controls: 0.06 ± 0.01, P < 0.016) despite similar average aortic dimensions for BAV (37 ± 1 mm) and TAV (39 ± 1 mm). Multivariate linear regression showed a significant correlation of maximal aortic diameter to age, PV, and normalized flow displacement (R(2) = 0.413, P < 0.001). CONCLUSION: A single acquisition of 4D flow MRI characterized local morphological and haemodynamic differences between groups along the aorta. BAV showed altered haemodynamics when compared with TAV in spite of having similar aorta dimensions. Maximal aorta diameter was associated with age, PV, and normalized flow displacement.
García et al. (Tue,) conducted a cross-sectional in Bicuspid aortic valve and dilated aorta (n=165). 4D flow MRI vs. Tricuspid aortic valve and controls was evaluated on Average peak velocity between the left ventricle outflow tract to sino-tubular junction (p=<0.016). Four-dimensional flow MRI demonstrated that patients with bicuspid aortic valves had higher average peak velocity (1.3 vs 1.2 m/s; P<0.016) compared to tricuspid valves despite similar dimensions.