Measurement of mitral valve area in patients with mitral stenosis by 3D echocardiography: A comparison between direct planimetry on 3D zoom and 3D quantification.

BACKGROUND: Measurement of the mitral valve area (MVA) in patients with mitral stenosis (MS) by 3D echocardiography (3DE) is usually done via 3D quantification (3DQ). The present study on patients with severe MS sought to evaluate the agreement regarding the MVA measurement between 3DQ and direct planimetry on 3D zoom and also between 3DE and 2DE.

METHODS: Twenty-six patients (22 female, mean age:34.5 ± 14.0 years) with severe MS diagnosed by 2D transthoracic echocardiography(2DTTE) underwent 3D transesophageal echocardiography (3DTEE). Direct planimetry, the pressure half-time (PTH), and the continuity equation(CE) constituted 3 conventional 2DTTE methods, and 3DQ and direct planimetry on 3D zoom comprised two 3DTEE methods applied for the MVA measurement. Agreement between the 2D and 3D methods was assessed using the Bland-Altman plot and measuring the intra-class correlation coefficient (ICC).

RESULTS: The mean MVA measured by 3DQ was significantly larger than that derived by direct planimetry on 3D zoom (0.935 ± 0.23 cm2 vs 0.846 ± 0.22 cm2 , respectively; P = 0.026). The agreement between 3DQ and 3D zoom for the MVA measurement was moderate to good by the Bland-Altman plot (ICC = 0.67). The mean MVA measured by 2DE (all 3 methods of direct planimetry, the PTH, and the CE) was significantly larger than that derived by 3DE (both methods of 3DQ and direct planimetry on 3D zoom) (all Ps < 0.05). A moderate agreement between 3DQ and 2D planimetry (ICC = 0.43) was found by the Bland-Altman plot.

CONCLUSIONS: The MVA measurement by direct planimetry on 3D zoom showed a moderate-to-good agreement with 3DQ; it may, thus, be used in clinical practice as a simple method for the measurement of the MVA in patients with MS.