Echocardiographic assessment of mitral regurgitation: discussion of practical and methodologic aspects of severity quantification to improve diagnostic conclusiveness

Abstract

The echocardiographic assessment of mitral valve regurgitation (MR) by characterizing specific morphological features and grading its severity is still challenging. Analysis of MR etiology is necessary to clarify the underlying pathological mechanism of the valvular defect. Severity of mitral regurgitation is often quantified based on semi-quantitative parameters. However, incongruent findings and/or interpretations of regurgitation severity are frequently observed. This proposal seeks to offer practical support to overcome these obstacles by offering a standardized workflow, an easy means to identify non-severe mitral regurgitation, and by focusing on the quantitative approach with calculation of the individual regurgitant fraction. This work also indicates main methodological problems of semi-quantitative parameters when evaluating MR severity and offers appropriateness criteria for their use. It addresses the diagnostic importance of left-ventricular wall thickness, left-ventricular and left atrial volumes in relation to disease progression, and disease-related complaints to improve interpretation of echocardiographic findings. Finally, it highlights the conditions influencing the MR dynamics during echocardiographic examination. These considerations allow a reproducible, verifiable, and transparent in-depth echocardiographic evaluation of MR patients ensuring consistent haemodynamic plausibility of echocardiographic results. Graphic abstract

Plausible Functional Diagnostics by Rational Echocardiography in the Assessment of Valvular Heart Disease - Role of Quantitative Echocardiography in the Assessment of Mitral Regurgitation

“…The proportionality between flow velocities and CSA are accepted for the estimation of the effective orifice area (EOA) in aortic valve stenosis (AS) by the continuity equation ( 1 , 3 , 5 ). Because of physical laws of conservation of mass and energy in communicating tubes the same physical principle applies to EROA and MR RegVol in MR ( 6 ). Thus, the EROA should theoretically be calculated by the equation CSA MA x VTI MAret = EROA x VTI MRret , where CSA MA is the cross-sectional area of the mitral annulus (MA), VTI MAret is the velocity time integral of the systolic retrograde flow velocities determined at the MA level by pw Doppler and VTI MRret is velocity time integral of the systolic retrograde transmittal flow velocities determined by cw Doppler.…”

“…“Disproportionate” FMR describes the disproportionateness between EROA and LVEDV ( 12 – 14 ). However, in MR patients—especially in FMR patients—LVEDV can only be interpreted if LV function will be considered described by LVEF ( 6 , 15 – 17 ). In isolated MR, LVSV tot can be determined by the addition of LVSV eff and the transmittal regurgitant volume (MR RegVol ) during systole provided that LVEDV and LVEF are properly assessed.…”

“…In conclusion, hemodynamics should be critically discussed and pose the question “whether hemodynamic considerations should be checked with respect to plausibility and should be integrated into the approach of assessing MR severity or not?” ( 6 ).…”

“…Clarifying the etiology of VHD is the first step of echocardiographic diagnostic. The grading of the severity of the valvular defects is the second target of a comprehensive functional assessment by echocardiography ( 5 , 6 ). Conventional echocardiographic modalities of transthoracic two-dimensional echocardiography (2D-TTE) to analyze VHD encompass M-Mode, 2D-imaging, color-coded, pulsed wave (pw), and continuous wave (cw) Doppler echocardiography ( 7 ).…”

“…These techniques are extended by tissue Doppler imaging (TDI), speckle tracking echocardiography (STE), multiplane and multidimensional (3D-) echocardiography and advanced approaches such as transesophageal echocardiography (TEE), contrast and stress echocardiography ( 8 ). All these modalities can be useful for a proper assessment of valvular defects and their hemodynamic consequences ( 5 , 6 ). The necessity of a quantitative comprehensive echocardiographic approach to analyze the pathophysiological sequelae of valvular defects is emphasized by using the example of mitral regurgitation (MR).…”