A novel method to measure mitral valve area in patients with rheumatic mitral stenosis using three-dimensional transesophageal echocardiography: Feasibility and validation

Abstract

Aims: Neither two- nor three-dimensional (3D) planimetry of the mitral valve (MV) orifice takes the mitral commissures into account. Thus, if the commissures are not completely fused, the MV orifice will not be planar, and MV area (MVA) will be underestimated. The study aimed to validate a novel method for measurement of the MVA using a software that traces the MV orifice including the commissures.

Methods and results: The study included 30 patients undergoing percutaneous balloon mitral valvuloplasty for severe rheumatic mitral stenosis. All performed 3D transesophageal echocardiography (TEE) immediately before the procedure. MVA was measured using the mitral valve navigation (MVN) software of the Philips Q-Lab 10.2 in a diastolic frame with maximum diastolic opening of the MV. Regular 3D planimetry of the MV orifice was also performed. Before balloon dilation, the MVA was calculated invasively using the Gorlin's formula. No significant difference was detected between MVN-derived MVA and Gorlin-derived MVA (0.98 cm² vs. 1.0 cm² , P = .33). A statistically significant difference was detected between Planimetry-derived MVA and Gorlin-derived MVA (0.8 cm² vs. 1.0 cm² , P < .001). There were significant linear correlations between MVN-derived MVA and Gorlin-derived MVA (r = .84, P < .001). Using Bland-Altman analysis, Gorlin-derived MVA showed better and relatively narrower limits of agreement with MVN-derived MVA than planimetry-derived MVA.

Conclusion: Measurement of the MVA using the MVN method is feasible and is more correlated to the invasively measured MVA than the 3D planimetry method. This is the most accurate method of measuring the MVA that takes MV commissures into account.

Keywords: mitral stenosis; mitral valve area; three-dimensional transesophageal echocardiography.