Comparative Analysis of Pre-Operative Transthoracic and Intraoperative Transesophageal Echocardiography for Grading Aortic Stenosis in Adults Undergoing Elective Aortic Valve Replacement: A Single-Center Experience

Background: Severe aortic stenosis necessitates precise preoperative evaluation to inform surgical decisions and ensure favourable patient outcomes. This study investigates the diagnostic discordance between pre-anaesthesia transthoracic echocardiography (TTE) and intraoperative transesophageal echocardiography (TEE) in patients undergoing elective aortic valve replacement (AVR) surgery. Material and Methods: A prospective randomized study enrolled 100 patients scheduled for AVR surgery due to aortic stenosis between January 2020 and December 2021. Pre-induction TTE and post-induction TEE examinations were compared. The study evaluated multiple parameters, including mean pressure gradient (PGm), peak jet velocity, aortic valve area (AVA) via continuity equation and planimetry, and dimensionless index (DI), across both TTE and TEE cohorts. Results: There were some apparent differences between measurements of TTE and TEE: A statistically significant difference in mean gradient across the aortic valve was noted while comparing TTE (57.16 ± 5.72mm Hg) with TEE (39.59 ± 5.97 mm Hg), which may have been a result of anesthetic effects. Similarly, the peak jet velocity in TTE was 506.06 ± 19.41 cm/s, whereas it was 386.72 ± 23.38 cm/s (P < 0.0001) for TEE. This shift saw 76% of the patients initially diagnosed with severe AS in TTE reassessed with moderate AS in TEE, showing that intraoperative situations played a big role. Using the continuity equation technique, the mean AVA for TTE and TEE were 0.84 cm² and 0.83 cm², respectively. PLANIMETRY AVA 0.88 ± 0.046 cm², in TTE, and 0.87 ± 0.055 cm², in TEE. Even if the valve area was decreased by 0.01 cm² with both approaches, there was no statistical significance (P = 0.15). In TTE and TEE, the DI mean was 0.20 (P = 0.62). Continuity equation, planimetry, and DI techniques were used; all patients had significant AS in TTE and TEE. Conclusion: Intraoperative TEE measurements often demonstrated reduced peak aortic jet velocities and mean pressure gradients compared to preoperative TTE assessments in patients with severe aortic stenosis, leading to potential underestimation of stenosis severity.AVA measurement by planimetry, continuity equation, and DI methods demonstrated more reliability.

Keywords: Aortic stenosis, continuity equation, dimension less index, planimetry.