Background: The mitral valve area (MVA) measurement in patients with mitral stenosis (MS) by 2D echo planimetry might be overestimated due to beam malalignment and difficulty in locating the mitral leaflet tips precisely. We aimed to compare MVA measured using 2D planimetry and 3D transesophageal echocardiography (TEE) and to analyze the discrepancy.
Methods: In 20 patients with MS (15 women; mean age 52 ± 12 years), MVA was determined by transthoracic 2D planimetry and 3D TEE image. We also measured angle (α) between the line of true mitral valve (MV) tip and the line of echo beam-to-MV tip. Left ventricular and atrial (LV and LA) dimensions and volumes, and LV ejection fraction (EF) were measured using 2D echo.
Results: There was an excellent correlation between MVA measurements using 2D planimetry and 3D TEE (r= 0.84, p <0.001). However, the former significantly overestimated the latter by 0.12 ± 0.21 cm² (p=0.02). By linear regression analysis, the difference between the two measurements correlated significantly with LA dimension from parasternal long-axis view (r=0.625, p=0.003), LA volume by area-length method (r=0.500, p=0.029), α (r=0.489, p=0.029), and LV EF (r=0.512, p=0.021), but not with LV dimensions or pulmonary artery pressure. Moreover, α showed a significant positive correlation with LA dimension (r=0.53, p=0.016). By multiple linear regression analysis, LA dimension and LV EF were the independent predictors of MVA measurement difference. Five patients (25%) showed a significant overestimation of MVA by 2D planimetry (≥0.2 cm² larger than MVA by 3D TEE). LA dimension ≥ 45mm (sensitivity of 100%, specificity of 73%) and LV EF ≤ 50% (sensitivity of 60%, specificity of 93%) were the best cut-off values for predicting significant overestimation by 2D planimetry.
Conclusion: MVA measured by 2D planimetry tends to overestimate MVA by 3D TEE. MVA measurement using 3D TEE seems to be useful especially in patients with large LA size which may cause a large discrepancy between MV tip plane and echo beam direction.
|
