Combining 2D Planimetry and Yeo’s Index Can Help Accurately Identify Patients with Severe Rheumatic Mitral Stenosis—A Perspective from a 3D Assessment Using Transoesophageal Echocardiography

Abstract

Background: Yeo’s index is a novel measure of the severity of rheumatic mitral valve stenosis (MS). It is derived from the product of the mitral leaflet separation index and dimensionless index. This study aims to validate Yeo’s index using a transesophageal echocardiogram (TEE) three-dimensional (3D) mitral valve area (MVA) as a comparator and to compare the concordance of existing echocardiographic measures of the MVA with TEE 3DMVA. Methods and Results: We studied 111 patients with rheumatic MS who underwent both transthoracic echocardiography (TTE) and a TEE assessment of MS severity. Yeo’s index, the MVA determined by 2D planimetry, pressure half-time (PHT) and continuity equation (CE) measured on TTE were compared with the TEE 3DMVA. With a linear correlation, Yeo’s index showed the best correlation with TEE 3DMVA (r2 = 0.775), followed by 2D planimetry (r2 = 0.687), CE (r2 = 0.598) and PHT (r2 = 0.363). Using TEE 3DMVA as comparator, Yeo’s index (ρc = 0.739) demonstrated the best concordance, followed by 2D planimetry (ρc = 0.632), CE (ρc = 0.464) and PHT (ρc = 0.366). When both Yeo’s index and 2D planimetry suggested significant MS, the positive predictive value was high (an AUC of 0.966 and a PPV of 100.00% for severe MS, and an AUC of 0.864 and a PPV of 85.71% for very severe MS). When both measures suggested the absence of significant MS, the negative predictive value was also high (an AUC of 0.940 and an NPV of 88.90% for severe MS, and an AUC of 0.831 and an NPV of 88.71% for very severe MS). Conclusions: Yeo’s index performed well in identifying severe MS when compared with TEE 3DMVA and may be a useful adjunct to existing methods of measuring MS severity. Combining it with 2D planimetry could further enhance its accuracy.