Association of Yeo's index with clinical outcomes in rheumatic mitral stenosis

Yeo's index, the product of the mitral leaflet separation index and dimensionless index of mitral valve (MV), was recently described to accurately identify severe rheumatic mitral stenosis (MS). We assess the association between Yeo's index and clinical outcomes in patients with rheumatic MS. We studied 297 patients with rheumatic MS. Clinical and echocardiographic data were obtained from the electronic medical record and Yeo's index was measured in all cases. The outcome studied was a composite of all cause death, heart failure (HF) hospitalisation, MV intervention and stroke or transient ischaemic attack. We also performed subgroup analysis of patients without pre-existing atrial fibrillation (AF) to assess for association with new onset AF. The median follow up was 6.3 years; 145 patients (48.8%) developed the composite outcome. Yeo's index (p < 0.001), mitral valve area (MVA) by pressure half-time (PHT) (p = 0.028) and planimetry (p < 0.001), age (p = 0.016), history of diabetes mellitus (p = 0.029), previous HF (p = 0.021), left ventricular ejection fraction (p = 0.022), and pulmonary artery systolic pressure (p = 0.007) were univariately associated with the composite outcome. Yeo's index remained independently associated with the composite outcome in multivariate analysis (p < 0.001, HR 0.094, 95% CI 0.260-0.340). This was primarily driven by MV intervention. In a subgroup analysis of patients without pre-existing AF, Yeo's index was independently associated with new onset AF (p = 0.024, HR 0.354, 95% CI 0.143-0.874). This demonstrated that Yeo's index was independently associated with clinical outcomes in patients with rheumatic MS which was mainly driven by MV intervention.