Prospective study comparing simultaneous transthoracic and transesophageal echocardiography aortic stenosis assessment

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Background Transthoracic echocardiography (TTE) is the gold-standard for aortic stenosis (AS) assessment. Transesophageal echocardiography (TEE) can be used alternatively, but measurement of hemodynamic components can be affected. Purpose We aimed to compare head-to-head TTE vs transesophageal echocardiography (TEE) assessment of AS. Methods We prospectively studied 56 patients with ≥moderate AS who underwent TTE (TTE1) and consecutive conscious sedation with simultaneous TEE and TTE (TTE2). Echocardiographic variables and AS types measured by TEE vs TTE2 and by TEE vs TTE1 were compared using paired tests and chi square tests. Based on conservative vs actionable implication, AS types were dichotomized into Group-A, comprising moderate and Normal-Flow Low-Gradient, and Group-B, comprising High-Gradient, Low Ejection-Fraction Low-Flow Low-Gradient, and Paradoxical Low-Flow Low-Gradient AS. Results TEE vs simultaneous TTE2 comparison demonstrated higher mean gradients (31.7 ± 10.5 vs 27.4 ± 10.5mmHg) and velocities (359 ± 60.6 vs 332 ± 63.1cm/sec) with TEE, but lower left ventricular outflow velocity-time-integral VTI1 (18.6 ± 5.1 vs 20.2 ± 6.1cm), all p < 0.001. This resulted in lower aortic valve area AVA (0.8 ± 0.21 vs 0.87 ± 0.28cm2), p < 0.001, and a net relative-risk of 1.86 of Group A to B upgrade. TEE vs (awake-state) TTE1 comparison revealed a larger decrease in VTI1 due to higher initial awake-state VTI1 (22 ± 5.6cm), resulting in similar Doppler-velocity-index (DVI) and AVA decrease with TEE, despite slight increase in mean gradients of 0.8mmHg (-1.44 to 3.04 CI) and in velocities of 10cm/sec (-1.5 to 23.4 CI). This translated into a net relative-risk of 1.92 of Group A to B upgrade vs TTE1. Conclusions TEE under conscious sedation overestimates AS severity compared with both awake state TTE and simultaneous sedation state TTE, accounted for by different Doppler insonation angle obtained in transapical vs transgastric position. The net result is a smaller DVI and AVA by TEE vs TTE. TEE carries a high sensitivity but a low specificity for severe AS compared with TTE during awake state. Abstract Figure. Spectral Doppler w/TTE vs simultan. TEE Abstract Figure. Cardiac CT planes simulating TTE vs TEE