Introduction: Transcatheter aortic valve implantation (TAVI) has become an established treatment option for patients with symptomatic severe aortic stenosis (AS) at increased risk for surgical complications. Transesophageal echocardiography (TEE) is the current gold-standard for direct measurement of aortic valve area (AVA). Little is known about the correlation of the AVA measured by TEE compared to computed tomography angiography (CTA). Direct measurement of AVA by CTA could add to the diagnostic pathway and even allow to forego TEE in some patients.

Methods and Results: We retrospectively analyzed datasets of 177 patients (92 men, mean age 80 years) with AS who had undergone CTA and TEE to compare the AVA. All datasets were analyzed by two independent raters with excellent inter-observer correlation coefficients of 0.97 for CTA (95% CI 0.96-0.98) and 0.98 for TEE (95% CI 0.97-0.98). The mean CTA based AVA was 0.96 ± 0.22 cm² compared to 0.86 ± 0.22 cm² by TEE. CTA systematically overestimated the AVA by 0.1 cm² when compared to TEE as the gold-standard, thus the cut-off value for severe AS when evaluated by CTA was 1.1cm².

Conclusion: Defining cut-off values for CTA-based AVA via correlation with TEE-based AVA is a further step towards a fully non-invasive assessment of the aortic valve in TAVI screening. Our results indicate that the AVA cut-off value for severe AS was 1.1cm² when measured by CTA.