Second, the effect of MPG on RgV is a function of its square root, such that a 25% reduction in MPG translates to a 13% reduction in RgV. First, hemodynamic changes tend to move the LV and LA pressures in the same direction such that the net effect on MPG is blunted. Systolic MPG is a primary determinant of MR severity, but its effect on RgV is mitigated by 2 factors. It is important to distinguish between techniques that measure anatomic versus effective ROA. C d is dependent on orifice geometry, flow, and fluid viscosity but is generally within the range of 0.80 to 0.85, which means that the effective ROA (EROA) is 15% to 20% smaller than the anatomic ROA. The constant C d in the hydraulic orifice equation accounts for contraction of the flow stream as it passes through the anatomic orifice and energy loss, because some of the potential energy (pressure gradient) is not converted to kinetic energy (velocity). 17 – 19 In some patients with mitral valve prolapse, acute afterload reduction may increase ROA and worsen MR severity. In FMR, therapies that result in reverse LV remodeling, especially carvedilol or cardiac resynchronization, may decrease ROA in some patients. When MR is caused by rheumatic heart disease or other postinflammatory conditions, ROA may be relatively fixed however, in patients with functional MR (FMR) caused by LV dysfunction, ROA tends to decrease during midsystole 16 and can vary significantly with loading conditions. However, ROA is dynamic and load dependent, 15 and there is an important interaction between load dependence of ROA and pathogenesis. Because ROA is a fundamental determinant of MR severity, 14 its measurement or calculation is paramount. Proper evaluation of the severity of MR requires careful consideration of each component of this equation. Finally, the role of cine magnetic resonance imaging (CMR) and cardiac catheterization in quantitation of MR will be discussed.Īccordingly, RgV in MR is determined by the anatomic regurgitant orifice area (ROA), discharge coefficient (C d), square root of the systolic mean pressure gradient (MPG) between the LV and left atrium (LA), and duration of MR (T). Integration of multiple quantitative parameters, including newly available 3D parameters, is needed for the final determination of MR severity. As with the ASE and EAE guidelines, we will emphasize the importance of an integrative approach. New evidence regarding the use of 3D echocardiography to quantify MR severity will be presented. Then, the practical application of various techniques for assessment of MR severity will be discussed, including their strengths and weaknesses. First, a theoretical framework for understanding the quantitative determinants of MR severity will be presented. 12 The present review aims to summarize those recommendations and to incorporate new data regarding the use of 3-dimensional (3D) echocardiographic parameters to determine MR severity. 11 In 2010, the EAE published an updated guideline document.

In 2003, the American Society of Echocardiography (ASE) and the European Association of Echocardiography (EAE) jointly published recommendations for quantification of valvular regurgitation. 8 Because surgery is only indicated in patients with severe MR, 9, 10 it is imperative to quantify MR severity accurately. The primary clinical tool for evaluation of the mechanism and severity of MR is echocardiography however, many patients referred to surgical centers for severe MR by echocardiography have only mild or moderate MR on quantitative evaluation.

1 Approximately 10% of people ≥75 years of age have significant MR, 1 and these patients have decreased survival regardless of whether MR is caused by a primary leaflet abnormality 2 or is secondary to left ventricular (LV) dysfunction. Significant mitral regurgitation (MR) is estimated to afflict >2 million Americans and is anticipated to increase in prevalence as the baby boomer population ages.

Customer Service and Ordering Information.

Stroke: Vascular and Interventional Neurology.

Journal of the American Heart Association (JAHA).

Circ: Cardiovascular Quality & Outcomes.

Arteriosclerosis, Thrombosis, and Vascular Biology (ATVB).

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