Evaluation of CT-derived aortic valve area and valve-to-annulus area ratio in patients with severe aortic stenosis undergoing transcatheter aortic valve implantation.

The CT-derived aortic valve area (AVA CT) ≤ 1.2 cm² suggests severe aortic stenosis (AS) but may not account for annular or body size variations. The valve-to-annulus area ratio (VTAAR) may improve AS severity assessment. This study evaluates AVA CT ≤ 1.2 cm² and VTAAR thresholds in severe AS patients. We retrospectively analyzed consecutive patients who underwent transcatheter aortic valve replacement (TAVR) for severe symptomatic AS at a tertiary center. AVA CT was measured via mid-systolic planimetry, and VTAAR was calculated as AVA CT divided by annular area. Severe AS was determined by Structural Heart Team consensus based on transthoracic echocardiography (TTE) and supplementary imaging. Among 343 patients (mean age 79.7 ± 8.4 years, 55.4% male), AVA CT was ≤ 1.2 cm² in 241 (70.3%) and > 1.2 cm² in 102 (29.7%). Applying a VTAAR cutoff of ≤ 0.3 improved CT sensitivity, identifying severe AS in 307 patients (89.5%) meeting either AVA CT ≤ 1.2 cm² or VTAAR ≤ 0.3. This approach reclassified 62 of 102 patients (61%) with AVA CT > 1.2 cm², with greater sensitivity in those with left ventricular ejection fraction (LVEF) < 50%, mean aortic valve pressure gradient < 40 mmHg, and patients with body surface area (BSA) > 1.95 m2. AVA CT ≤ 1.2 cm² alone is not a sensitive marker for severe AS. Adding VTAAR ≤ 0.3 enhances CT's sensitivity, particularly in low gradient AS and large BSA patients. If validated prospectively, these CT metrics could aid AS severity assessment when TTE is inconclusive.