Incremental Value of Transesophageal Echocardiography Integrated with Transthoracic Echocardiography in the Assessment of Aortic Stenosis Severity.

Background: Transthoracic echocardiography (TTE) is the standard method for evaluating the severity of aortic stenosis (AS), while transesophageal echocardiography (TEE) is useful for morphologic characterization. The study aim was to assess the impact of complementary TEE to TTE in refining hemodynamic assessment of AS severity.

Methods: A retrospective analysis was conducted of sequential TTE and TEE studies performed in 100 patients with moderate or severe AS confirmed on prior TTE. The left ventricular outflow tract (LVOT) velocity-time-integral (VTI1) and the aortic valve velocity-time integral (VTI2) were measured for both modalities. The highest values of VTI1 and VTI2 and mean gradients and peak velocities were selected from the sequential TTE/TEE study for indexed aortic valve area (AVAi) calculation and AS severity determination through an integrated assessment.

Results: AVAi determined by TTE was not significantly different from that determined by TEE (mean difference -0.008 cm2; p = 0.38). The dimensionless velocity index (DVI) was higher when assessed by TTE than by TEE (mean difference 0.0126 ± 0.04; p = 0.003). Using the integrated AS assessment, six of 13 patients with a TTE-based diagnosis of moderate AS were re-classified as severe AS. A slight lowering of the recommended TTE-derived DVI threshold for severe AS, from 0.25 to 0.24, improved the ability to discriminate moderate versus severe AS, as determined by the integrated assessment.

Conclusions: TEE integrated with TTE may improve the detection of severe AS, particularly in patients with moderate AS criteria assessed by TTE, but with a DVI ratio ≤0.24.