ECHOCARDIOGRAPHIC QUANTITATION OF MITRAL REGURGITATION
Hari P. Chaliki, M.D.,
Mayo Clinic, Scottsdale, AZ, USA
Mitral regurgitation (MR), either acute or chronic, can be due to valvular pathology or the supporting apparatus or ventricular pathology. Currently, echocardiography is used in most cases to determine the etiology and severity of MR. Although, semi-quantitative method such as two dimensional color flow jet area is still used for MR assessment, it is less reliable when compared to other quantitative methods integrated with all the available semi-quantitative information. Shape and density of the mitral regurgitation continuous wave Doppler jet signal, mitral and pulmonary vein inflow pattern, size of the left atrium and left ventricle, integrity of the mitral leaflets or the supporting structures when used in conjunction with additional parameters such as width of the vena contracta, regurgitant volume and effective regurgitant orifice area will vastly improve the assessment of MR.
Two dimensional quantitative methods such as continuity method and Proximal Isovelocity Surface Area (PISA) method are clinically more useful given their ability to more precisely determine the MR severity. Specifically, one can precisely estimate the mitral regurgitation volume and effective regurgitant orifice area. When MR volume exceeds 60 mls and effective regurgitant orifice area exceeds 0.4 cm2, one is considered to have severe MR based on American society of echocardiography and American college of cardiology guidelines.
Three dimensional (3D) echocardiography now make it possible to not only visualize the mitral valve anatomy better but also measure the vena contracta area and proximal isovelocity surface area without the need for geometric assumptions. Recent studies demonstrated that vena contracta area measurement and 3D PISA measurement using 3D color Doppler echocardiography improved quantitation of MR when compared to 2D dimensional methods or conventional echo-Doppler methods when magnetic resonance imaging was used as gold standard.