975-82 Role of Biplane Transesophageal Echocardiography in Assessing Severity of Aortic Stenosis: Planimetry vs. Continuity Equation

Abstract

Accurate calculation of aortic valve area (AVA) by the continuity equation (CE): A 1 V 1 N 2 , relies on an optimal 2D imaging of A 1 (LV outflow tract [LVOT] diameter/2 π. To evaluate: 1) whether transesophageal echo (TIE) LVOT can be utilized as an alternative to transthoracic echo (TIE), and 2) to compare the AVA measured by direct TEE planimetry (PL) in the same population, 48 pts with suspected aortic stenosis (AS) underwent TIE simultaneously (24 pts) or within 7 days (24 pts) prior to catheterization (CATH). When simultaneously, Doppler signals were superimposed to CATH pressure tracings. Biplane TEE was done within 48-hrs of CATH. AVA by PL, Dopplerderived maximal instantaneous gradient (MIG), mean gradient (mG) and AVA using LVOT area from TTE and from TEE were compared with CATH. TTE-LVOT was suboptimal in 9 (19%) pts, and in none by TEE. AVA by PL was feasible in 40 (83%) pts. TIE TEE PL CATH MIG(mmHg) 55.9 * – – 62.4 mG(mmHg) 41.8 * – – 45.8 LVOT area (cm 2 ) 3.9 4.0 † – – AVA(cm 2 ) 0.91 * 0.90 *† 0.88 * 0.89 * comparison with CATH p < 0.001 † comparison with TIE p < 0.001) Correlations between Doppler- and CATH-derived gradients were excellent either simultaneously or not (MIG = 0.96, SEE = 6, p < 0.001; mG, r = 0.96, SEE = 4, P < 0.001; AVA, r 0.92, SEE 0.18, P < 0.0011. PL-AVA and CATH correlated less closely (r 0.78, SEE 0.22, P < 0.001). In conclusion: 1) TEELVOT is measurable in 100% of AS pts and can be accurately used as an alternative when TIE-LVOT is suboptimal; 2) AVA-PL is measurable in 83% of AS pts and less accurate than the CE; and 3) Doppler-derived gradients do not need to be done simultaneously to accurately reflect CATH as long as Doppler is performed in dose temporal relation and by an experienced sonographer.