Discussion on the Application of Combined Transthoracic and Transesophageal Echocardiography in the 'Four-Step Repair Method' for Treating Rheumatic Heart Valve Disease and Its Short-Term Outcomes

This study aims to evaluate the therapeutic effectiveness of using combined transthoracic and transesophageal echocardiography in the four-step repair method that preserves the mitral valve structure in patients with rheumatic heart disease (RHD), by assessing changes in structural and hemodynamic parameters before and after surgery.

This study retrospectively collected clinical and imaging data from 105 patients with rheumatic heart disease who underwent heart valve repair surgery between February 2023 and July 2024. All patients underwent transthoracic and transesophageal echocardiography before and after the surgery. The mitral valve structural characteristics and quantitative hemodynamic analysis parameters were evaluated, including leaflet opening and closing angles, leaflet thickening, leaflet adhesion sites, papillary muscle fusion, chordal retraction, presence of thrombus, mitral valve flow velocity, mean pressure gradient, and instantaneous regurgitation area. Postoperative echocardiographic follow-up was performed prior to hospital discharge (median 6 days, range 5-7 days). Statistical methods such as the chi-square test and paired t-test were used to compare these parameters before and after surgery. Short-term outcomes were defined as in-hospital clinical events and echocardiographic findings at discharge.

Among the 105 patients with rheumatic mitral stenosis, pre-operative findings included left atrial enlargement (n = 68), atrial fibrillation (n = 44), left atrial thrombus (n = 3), and pulmonary hypertension (n = 24). Pre-operative TTE and TEE demonstrated strong concordance with intraoperative findings for diagnosing mitral leaflet thickening, as indicated by Cohen's κ values of 0.88 (95%CI: 0.80-0.96) and 0.86 (95%CI: 0.79-0.93), respectively. McNemar's test revealed no significant asymmetry in discordant pairs for leaflet thickening (P = 0.125 for TTE; P = 0.065 for TEE). For the assessment of subvalvular pathology including commissural adhesion, chordal retraction, and papillary muscle fusion, TEE exhibited excellent agreement with surgical observations (κ: 0.82-0.90), whereas TTE showed moderate to substantial agreement (κ: 0.45-0.78). The mean cardiopulmonary bypass time was 162.05 ± 42.01 minutes. Post-operative assessment confirmed technical success of the repair procedure in all 105 patients, characterized by the resolution of mitral stenosis and significant improvement in leaflet mobility. Residual mitral regurgitation was mild or less in 98% of patients, with three cases demonstrating moderate regurgitation that did not require immediate re-intervention.

While TTE and TEE are equally accurate in detecting leaflet thickening, TEE provides superior visualization of subvalvular pathology. The combined perioperative use of TTE and TEE provides comprehensive multiparametric assessment and appears clinically useful for guiding and evaluating the four-step repair technique in rheumatic mitral valve disease. However, the incremental benefit of the combined approach over either modality alone cannot be quantified from this single-cohort design and warrants prospective comparative study.