Comparative Accuracy of Transthoracic and Transesophageal Echocardiography Versus Surgical Sizing of the Aortic Annulus: Insights from a Retrospective Validation Study

Abstract Background: Accurate preoperative assessment of the aortic annulus is critical for the success of aortic valve replacement (AVR), particularly in patients undergoing transcatheter aortic valve implantation (TAVI). Transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) are commonly employed non-invasive modalities for annular measurement; however, their precision compared to intraoperative surgical sizing remains debated. Objective: To assess and compare the precision of TTE and three-dimensional reconstructed TEE in measuring aortic annulus diameter against direct surgical sizing. Methods: In this retrospective study, 106 patients who underwent AVR between January 2019 and December 2023 were included. Aortic annular dimensions from TTE and TEE were compared to intraoperative surgical measurements (SM). Subgroup analyses were conducted based on age, sex, valve morphology, and severity of aortic stenosis (AS) and aortic insufficiency (AI). Wilcoxon signed-rank tests and Pearson correlations were used to assess discrepancies and relationships between modalities Results: The study population had a mean age of 68.4 ± 9.6 years, with 56% male (n=59) and 44% female (n=47). The mean surgical annulus diameter was 24 ± 2 mm, with TTE and TEE yielding lower values (22 ± 3 mm and 23 ± 3 mm, respectively). Both non-invasive methods significantly underestimated the annulus size (TTE: −2 ± 4 mm, p<0.001; TEE: −1 ± 4 mm, p=0.010). TEE demonstrated better accuracy in males, patients under 60, and those with tricuspid valves or moderate-to-severe AS. The correlation between TTE and TEE was strong (r=0.790, p<0.001), but both modalities had weak correlation with surgical measurements. Conclusion: TTE and TEE both underestimate the aortic annular diameter compared to surgical measurement, with TEE providing improved accuracy in select patient populations. These findings underscore the need for individualized imaging strategies in AVR planning. Future prospective studies incorporating multimodal imaging—including MDCT and 3D echocardiography are warranted to refine preoperative annular assessment and enhance procedural outcomes.