Assessment of aortic valve area on cardiac computed tomography in symptomatic bicuspid aortic stenosis: Utility and differences from Doppler echocardiography.

Background: In this study, we investigate the utility of geometric orifice area (GOA) on cardiac computed tomography (CT) and differences from effective orifice area (EOA) on Doppler echocardiography in patients with bicuspid aortic stenosis (AS).
Methods: A total of 163 patients (age 64 ± 10 years, 56.4% men) with symptomatic bicuspid AS who were referred for surgery and underwent both cardiac CT and echocardiography within 3 months were studied. To calculate the aortic valve area, GOA _CT was measured by multiplanar CT planimetry, and EOA _Echo was calculated by the continuity equation with Doppler echocardiography. The relationships between GOA _CT and EOA _Echo and patient symptom scale, biomarkers, and left ventricular (LV) functional variables were analyzed.
Results: There was a significant but modest correlation between EOA _Echo and GOA _CT ( r = 0.604, p < 0.001). Both EOA _Echo and GOA _CT revealed significant correlations with mean pressure gradient and peak transaortic velocity, and the coefficients were higher in EOA _Echo than in GOA _CT . EOA _Echo of 1.05 cm ² and GOA _CT of 1.25 cm ² corresponds to hemodynamic cutoff values for diagnosing severe AS. EOA _Echo was well correlated with the patient symptom scale and log NT-pro BNP, but GOA _CT was not. In addition, EOA _Echo had a higher correlation coefficient with estimated LV filling pressure and LV global longitudinal strain than GOA _CT .
Conclusion: GOA _CT can be used to evaluate the severity of bicuspid AS. The threshold for GOA _CT for diagnosing severe AS should be higher than that for EOA _Echo . However, EOA _Echo is still the method of choice because EOA _Echo showed better correlations with clinical and functional variables than GOA _CT .
Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
(Copyright © 2022 Kim, Lee, Seo, Suh, Cho, Hong, Ha, Kim and Shim.)