Assessment of mitral valve area by 3D echocardiography in rheumatic mitral stenosis: Validation of offline 3D planimetry measure

Abstract

The aim of this study is to validate the feasibility and accuracy of performing offline planimetric measurement of mitral valve area (MVA) using real time 3-dimensional transesophageal echocardiography (3D TEE), and to compare it with methods used routinely in clinical practice: 2-dimensional (2D) planimetry and pressure half time (PHT). Measurements of MVA by (2D) planimetry and Doppler (PHT) remain the mainstay methods used in routine clinical practice. 3D TEE provides more improved accuracy and reproducibility over 2D methods in theassessment of mitral valve morphology. Planimetry of the MVA by 3D echocardiography has only been done through multi-planar reconstruction of the mitral valve orifice. However using offline 2D image calibration and measurement tools allows us to measure MVA by 3D planimetry. 45 patients with moderate to severe rheumatic mitral stenosis were referred for transthoracic and transesophageal (TEE) echocardiography 2D and 3D. Offline planimetric measurement of MVA obtained from real time 3D TEE zoom views of the mitral valve from both left atrial (MVA 3DPLA) and left ventricular side (MVA 3DPLV) were compared to MVA by 2D planimetry and PHT. MVA measurements (2D and 3D) were reported by two independent readers and interobserver variability was assessed. MV areas measured by these three methods were compared using Altman and Bland methods and Shukla’s correlation. The Altman and bland analysis showed consistency among all three measurements methods. 3 DTEE showed the least variability across different clinicians compared to 2 DTEE and PHT, Mean difference 0.08, −0.15, and −.17, respectively. 3DTEE planimetry appears to be a consistent technique for measuring MVA and provides the least variability in practical setting.