Multimodality assessment of aortic valve area in aortic stenosis: a multicenter validation study

Abstract Objectives Transthoracic echocardiography (TTE) is the standard modality for grading aortic stenosis (AS) severity. Transesophageal echocardiography (TOE) allows direct aortic valve area (AVA) planimetry (AVATOE), while computed tomography angiography (CTA) offers a non-invasive alternative (AVACTA). This study aimed to evaluate the correlation between AVA measurements across modalities and to determine a diagnostic AVACTA threshold for severe AS. Methods This retrospective study included a single-center derivation cohort of 176 patients (mean age 80.0 ± 7.7 years, 52.8% male) with moderate to severe AS who underwent full-cycle CTA, TTE, and TOE. AVACTA was measured by two independent raters. Correlation with AVATOE and other parameters was assessed. Receiver operating characteristic (ROC) analysis was used to define an optimal AVACTA threshold for severe AS, which was validated in a multi-center cohort of 407 patients (mean age 80.9 ± 6.7 years, 52.8% male) with comparable characteristics. Results Mean AVACTA was 0.96 ± 0.28 cm² with a high interrater reliability (IRR = 0.84), compared to a mean AVATOE of 0.88 ± 0.26 cm² (Pearson’s r = 0.73). ROC analysis identified 0.96 cm² as the optimal AVACTA threshold for diagnosing severe AS (AUC = 0.846; sensitivity = 71.7%; specificity = 89.8%) compared to TOE grading. This threshold yielded good diagnostic performance in the validation cohort (AUC = 0.817; sensitivity = 78.2%; specificity = 72.6%). Conclusions AVACTA demonstrated high reliability, showing a strong correlation with AVATOE. The 0.96 cm² threshold, defined in the derivation cohort, performed well in the validation cohort for assessing aortic stenosis severity.