Leow Ryan, Kong William K F, Li Tony Yi-Wei, Poh Kian-Keong, Sia Ching-Hui, Yeo Tiong-Cheng
Department of Cardiology, National University Heart Centre Singapore (NUHCS), Singapore.
Department of Cardiology, NUHCS, and the Department of Medicine, Yong Loo Lin School of Medicine (YLLSoM), National University of Singapore (NUS), Singapore.
Int J Cardiol. 2023 Dec 1;392:131350. doi: 10.1016/j.ijcard.2023.131350. Epub 2023 Sep 7.
A mitral leaflet separation index (MLSI), measuring the anatomical separation of the mitral valve (MV) leaflet tips in diastole, was previously described as an accurate method of assessing mitral stenosis (MS). We propose a novel modification of the MLSI by including a hemodynamic assessment which we term Yeo's index that may improve its diagnostic performance.
We retrospectively studied 174 patients with varying severity of MS without significant mitral regurgitation, aortic valve disease or ventricular septal defect. MLSI was measured in 2 orthogonal views on transthoracic echocardiography as previously described. MV dimensionless index (DI) was calculated by dividing the left ventricular outflow tract pulsed-wave Doppler time velocity integral (TVI) by the MV continuous-wave Doppler TVI. We defined Yeo's index as the product of MLSI and DI. With linear correlation, Yeo's index demonstrated good correlation against MVA by planimetry (r = 0.728), pressure half-time (r = 0.677), and continuity equation (r = 0.829), with improved performance over the MLSI. Using ROC analysis, Yeo's index demonstrated good ability to correctly classify MS as severe (MVA ≤1.5cm) (AUC 0.874, 95% CI 0.816-0.920). Yeo's index ≤0.260 cm correctly classified severe MS with sensitivity of 82% and specificity of 80%. Presence of AF did not affect the performance of Yeo's index. Yeo's index ≤0.147 cm also identified very severe MS (MVA ≤ 1.0 cm) with specificity of 94% and sensitivity of 78%.
Yeo's index performed well in identifying severe MS and may be a useful adjunct to existing measures of MS severity.
二尖瓣瓣叶分离指数（MLSI）用于测量舒张期二尖瓣（MV）瓣叶尖端的解剖学分离，此前被描述为评估二尖瓣狭窄（MS）的一种准确方法。我们提出了一种对MLSI的新颖改进方法，即纳入血流动力学评估，我们将其称为杨式指数，这可能会提高其诊断性能。
我们回顾性研究了174例MS严重程度各异且无明显二尖瓣反流、主动脉瓣疾病或室间隔缺损的患者。如前所述，在经胸超声心动图的2个正交视图中测量MLSI。通过将左心室流出道脉冲波多普勒时间速度积分（TVI）除以MV连续波多普勒TVI来计算MV无量纲指数（DI）。我们将杨式指数定义为MLSI与DI的乘积。通过线性相关分析，杨式指数与通过平面测量法测得的二尖瓣口面积（MVA）（r = 0.728）、压力减半时间（r = 0.677）和连续方程（r = 0.829）显示出良好的相关性，其性能优于MLSI。使用ROC分析，杨式指数显示出将MS正确分类为重度（MVA≤1.5cm²）的良好能力（AUC 0.874，95% CI 0.816 - 0.920）。杨式指数≤0.260cm²正确分类重度MS的敏感性为82%，特异性为80%。房颤的存在并不影响杨式指数的性能。杨式指数≤0.147cm²也能识别极重度MS（MVA≤1.0cm²），特异性为94%，敏感性为78%。
杨式指数在识别重度MS方面表现良好，可能是现有MS严重程度测量方法的有用辅助手段。
