Transthoracic Echocardiography versus Computed Tomography for Ascending Aortic Measurements in Patients with Bicuspid Aortic Valve

Background: Ascending aorta dilatation is common in bicuspid aortic valve (BAV). The aim of this study was to investigate agreement of transthoracic echocardiographic (TTE) measurement of the sinuses of Valsalva and the tubular mid-ascending aorta (Asc-Ao) compared with electrocardiographically gated computed tomographic angiographic (CTA) assessment in patients with BAV. Methods: Fifty-three patients with BAV (mean age, 54 ± 14 years; 74% men) who underwent both TTE and CTA imaging for ascending aortic assessment were retrospectively identified. All studies were measured de novo by experts. TTE measurements were obtained at the sinuses and the Asc-Ao, at both systole and end-diastole, using both leading edge-to-leading edge (L-L) and inner edge-to-inner edge (I-I) methods in the parasternal long-axis (LAX) view. The sinuses were also measured in the parasternal short-axis (SAX) view using the same methods plus mid-diastole. CTA measurements were obtained in diastole using outer wall-to-outer wall (O-O) and inner wall-to-inner wall (I-I) methods. Correlation and agreement between the two imaging modalities were assessed using Lin correlation and Bland-Altman analysis, respectively. Results: Compared with CTA O-O maximum sinuses diameter, the best correlation and agreement were obtained using the TTE SAX mid-diastolic L-L method (ρ = 0.89, 2.6 ± 2.3 mm, respectively). Compared with CTA O-O maximum Asc-Ao diameter, the TTE LAX systolic L-L method (ρ = 0.93, 1.3 ± 2.5 mm) was best. Compared with CTA I-I maximum sinuses diameter, the TTE SAX mid-diastole L-L method (ρ = 0.95, 0.6 ± 2.2 mm) was unbiased. Compared with CTA I-I maximum Asc-Ao diameter, the TTE LAX end-diastolic L-L method (ρ = 0.95, 0.6 ± 2.4 mm) was unbiased. Conclusions: In patients with BAV aortopathy, unbiased agreement between CTA and TTE imaging can be obtained between the CTA I-I method and TTE SAX mid-diastolic L-L method for the sinuses and the TTE LAX end-diastolic L-L method for the Asc-Ao. When using the CTA O-O method, the best agreement is obtained with the TTE SAX mid-diastolic L-L method for the sinuses (bias ∼2 mm) and the TTE LAX systolic L-L method (bias ∼1 mm) for the Asc-Ao.