Assessment of the Mitral Valve
Robert M. Savage1
Solomon Aronson1
Colleen G. Koch2
1OUTLINE AUTHORS
2ORIGINAL CHAPTER AUTHOR
▪ KEY POINTS
The mitral valve complex consists of the mitral annulus, anterior and posterior mitral valve leaflets, chordal tendons, and left ventricular myocardium. Structural integrity of the mitral valve requires that all of the elements of the apparatus function appropriately.
The comprehensive evaluation of a patient with mitral regurgitation includes the integration of qualitative, semiquantitative, and quantitative transesophageal echocardiography assessments along with clinical features of the patient’s presentation.
Rheumatic heart disease continues to be the primary etiology of mitral stenosis. Characteristics include variable degrees of leaflet and subvalvular thickening, calcium deposition, and reduction in leaflet mobility.
The splitability score provides an overall summary score reflecting the degree of leaflet deformity in patients with rheumatic mitral stenosis. Higher scores reflect advanced leaflet deformity.
The proximal isovelocity surface area (PISA) method may be applied to quantitatively estimate the degree of mitral regurgitation, as well as the degree of mitral stenosis. A correction factor is applied to estimate valve area for mitral stenosis as the angle subtended by the mitral leaflets creates a funnel-shaped surface.
I. ANATOMY OF THE MITRAL VALVE
Anatomic components of the mitral valve complex include the left atrial wall, mitral annulus, anterior and posterior leaflets, the chordal tendons, and the anterolateral and posteromedial papillary muscles.
The anterior leaflet is triangular and subtends 1/3 of the annulus. It has a longer base-to-margin length than the posterior leaflet.
Part of the anterior annulus has a common attachment to the fibrous skeleton of the heart with the left coronary cusp and half of the noncoronary cusp of the aortic valve
Standard nomenclature adopted by the Society of Cardiovascular Anesthesiologists and American Society of Echocardiography divides the anterior and posterior leaflets into three segmental regions.
II. STRUCTURAL INTEGRITY OF THE MITRAL VALVE
A. Mitral regurgitation
Carpentier and colleagues categorized mitral valve dysfunction based upon normal, excessive, or restrictive leaflet motion.
Two-dimensional echocardiography changes suggestive of severe mitral insufficiency include left atrial dimensions of ≥5.5 cm and left ventricular diastolic dimension of ≥7 cm.
Increased signal intensity of a continuous wave Doppler signal and a complete envelope are consistent with severe mitral regurgitation.
A peak transmitral E-wave velocity of greater than 1.2 m/s is consistent with severe mitral regurgitation.
A color flow Doppler maximal jet area greater than 6 cm2 is predictive of severe mitral regurgitation. However, several factors can influence the size of the jet, including technical factors (gain, frame rate, transducer frequency), hemodynamics, left atrial compliance, and eccentric shape.
A blunted or reversed systolic component of the pulmonary venous waveforms is consistent with significant mitral regurgitation. However, pulmonary venous flow patterns are also influenced by left ventricular diastolic function (relaxation and compliance), changes in loading conditions, left atrial compliance and function, and arrhythmias.
The vena contracta is the narrowest part of the regurgitation jet as imaged with color flow Doppler when the jet emerges from the regurgitant orifice. A vena contracta width ≥6 mm is consistent with severe mitral regurgitation.
Regurgitant orifice area (ROA) can be measured with two-dimensional and pulsed-wave Doppler echocardiography or with the PISA method. An ROA ≥ 0.4 cm2 is associated with severe mitral regurgitation.
A regurgitant volume greater than 60 mL and a regurgitant fraction greater than 55% are associated with severe mitral regurgitation.
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
