Background: Discordances between the calculated aortic valve area (AVA) based on the continuity equation and trans-aortic pressure gradients are common when assessing patients for the severity of aortic stenosis. Previous studies have shown that 2D and 3D trans-thoracic echocardiography (TTE) may underestimate the calculated left ventricular outflow tract (LVOT) area, leading to underestimation of calculated AVA.
Purpose: To compare the direct measurement (planimetry) of LVOT area using 3D Trans- Esophageal Echocardiography (TEE) to the calculated LVOT area based on LVOT diameter obtained with 2D TTE, 2DTEE and 3D TEE.
Methods: A, single center study of patients who were referred for an echocardiographic assessment due to suspected significant aortic stenosis. Inclusion criteria were: Calculated AVA≤ 1.0 cm² or mean transvalvular pressure gradient ≥ 40 mmHg and preserved LV ejection fraction (≥ 50%). Patients with significant aortic or mitral regurgitation were excluded.
Results: There were 54 patients, mean age 82±6 years. LVOT area measured by 3D planimetry was 3.4±0.7cm², significantly larger than calculated areas measured by 2D TTE (3.1 ± 0.2 cm²; p< 0.001), 2D TEE and (3.1±0.25cm², p<0.02) and 3D TEE (3.0 ± 0.3cm², p<0.0002).
Conclusion: 3D TEE LVOT planimetry provides a larger LVOT area and may be more accurate than LVOT area calculation based on diameter measurements using 2D TTE, 2D and 3D TEE. This finding may have clinical implications regarding the need and timing for aortic valve intervention in patients with AS.
