Tabriz University of Medical Sciences Journal of Cardiovascular and Thoracic Research 2008-5117 18 2 2026 06 30 Investigating the relationship between mitral leaflet separation index and severity of mitral valve stenosis using two and three-dimensional measurement methods in Transesophageal echocardiography 109 115 10.34172/jcvtr.33359 EN Alaaldin Hoshmand https://orcid.org/0009-0008-0859-6845 Naser Khezerlouy-Aghdam Rezvaneh Salehi Somayeh Abolhasani Elnaz Javanshir https://orcid.org/0000-0003-4244-7735 Journal Article 10.34172/jcvtr.33359 2024 09 18 2026 01 10 Introduction: cardiologists use several echocardiographic methods to evaluate the Mitral Stenosis (MS) severity. Determination of mitral valve area (MVA) by three- dimensional transesophageal echocardiography (3D TEE) planimetry has the best correlation with anatomic area of the mitral orifice and is probably the reference method. This study was designed to examine the relationship between mitral leaflet separation index (MLSI) measured by TEE which is a simple and accessible method and MVA calculated by 3D Multiplanar reconstruction (3D-MPR) planimetry in TEE as the reference but less accessible method for evaluation the MLSI accuracy in prediction of the severity of MS. Methods: 72 patients with MS were included in this study. Exclusion criteria were suboptimal echocardiographic images, severe mitral valve calcification, artificial heart valves, a history of mitral valve repair surgery, or contraindications to TEE. After obtaining written informed consents from all patients. Comprehensive TTE and TEE were performed and MLSI by 2D TTE and 2D TEE and MVA By 3D MPR planimetry were assessed. SPSS version 25 was used for performing the analyzes and a P-value less than 0.05 was considered statistically significant. Results: The average age of the patients was 57.81±12.22 and 48 (66.7%) patients were female. There was a significant correlation between MVA by 3D MPR and MLSI 2D TTE (r=0.94, P<0.01) and MLSI 2D TEE (r= 0.96, P<0.01) methods. Conclusion: MLSI 2D TTE and MLSI 2D TEE are positively correlated to MVA measured by 3D MPR planimetry and MLSI can be useful in discriminating different grades of MS severity.