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Incremental Value of Transesophageal Echocardiography Integrated with Transthoracic Echocardiography in the Assessment of Aortic Stenosis Severity
Shmuel Schwartzenberg, Mordehay Vaturi, Daniel Monakier, Alexander Sagie, Ran Kornowski, Yaron Shapira.
Rabin Medical Center, Petah Tikva, Israel.

Background: Transthoracic echocardiography (TTE) is the standard method for evaluation of aortic stenosis (AS) severity, whereas transesophageal echocardiography (TEE) is useful for complementary morphologic characterization.
Methods: We retrospectively assessed the impact of complementary TEE to TTE in assessment of AS severity through standard hemodynamic parameters in 100 patients with moderate or severe AS on prior TTE. The left ventricular outflow tract (LVOT) velocity-time integral (VTI1) and the aortic valve velocity-time integral (VTI2) were measured on both modalities. Indexed aortic-valve-area (AVAi) was calculated through the continuity equation using the highest values of VTI1 and VTI2, whether from the TTE or TEE study. Similarly, the highest transvalvular mean gradients and peak velocities were selected from the combined TTE and TEE study. LVOT diameter was smaller by TTE when compared to TEE (mean difference -0.0860.12cm, p<0.001).
Results: Calculated AVAi by TTE was not significantly different than AVAi by TEE (mean difference -0.008 cm2, p=0.38). Dimensionless-velocity-index (DVI) was higher per TTE than per TEE (mean difference 0.0126 0.04, p = 0.003). 6 out of 13 (46.2%) of patients with moderate AS by TTE were reclassified as severe AS by integrated TTE and TEE assessment. When examining the AHA guidelines' recommended cut-off value of DVI<0.25, we found that the sensitivity of TTE to detect severe AS is 84.9%, specificity is 57.1%, positive predictive value (PPV) is 95%, and negative predictive value (NPV) is 22%. A slightly lower cut off value for DVI of 0.24, yields better discrimination, with sensitivity of 82.8%, specificity of 85.7%, PPV of 98.7%, and NPV of 27.3%.
Conclusions: TEE integrated with TTE may improve detection of severe AS, particularly in patients with moderate AS criteria by TTE but with a DVI ratio ≤ 0.24.


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