Valves

Mitral valve

Anatomy

The mitral valve consists of two leaflets, the anterior (A) and the posterior valve leaflet (P), which together have a surface area of 4-6cm. At the inner edges of the leaflets chordae tendinae are attached, which ensure that the leaflets did not prolapse back into the atria during systole. The chordae attach to two large papillary muscles, that are part of the muscular tissue of the left ventricle.

Mvalv

The mitral valve can be visualized in many views: PLAX, PSAXmv, AP4Ch, AP5Ch, AP2Ch, AP3Ch and subcostaal4Ch. A prolapse of the MV is best assessed on PLAX. However, mitral regurgitation should be assessed in all views. In case of major abnormalities of the mitral valve 3D TEE has additional value in assessing the anatomy and function.

Scallop partition of mitral valve

Figure-1-Four-imaging-planes-to-assess-the-precise-localization-of-prolapsed-or-flailMVtee

Regurgitation

Quantification of mitral valve regurgitation

MR severity classes 𝜁 Mild Moderate Moderate Severe
  Grade 1 or 1+ Grade 2 or 2+ Grade 3 or 3+ Grade 4 or 4+
Qualitative
Valve morphology None or mild leaflet abnormality Moderate leaflet abnormality Moderate leaflet abnormality Flail leaflet / large coaptation defect
  or minimal tenting or moderate tenting or moderate tenting or severe tenting
Colour flow MR jet Small, central Intermediate Intermediate Very large central jet or eccentric jet adhering,
        swirling and reaching the posterior wall of the LA
  Usually <4cm² Usually 4-6cm² Usually 6-8cm² Usually >8cm²
  <20% of LA 20-30% of LA 30-40% of LA >50% of LA
Flow convergence zone 𝛼 No or small faint Dense Dense Large throughout systole, dense, holosystolic
CW signal of MR jet Parabolic Partial or parabolic Parabolic or triangular Triangular
Semi quantitative
Vena contracta width (mm) <3 3 to <5 5 to <7 ≥7 (>8 for biplane) 𝛽
Pulmonary vein flow Systolic dominance Variable Systolic blunting Systolic pulmonary vein flow reversal 𝛾
MV inflow A wave dominant 𝛽 Variable E-wave dominant (E>1.2m/s) 𝜀 E-wave dominant (E>1.2m/s) 𝜀
VTI mitral / VTI LVOT <1 Intermediate >1.2 𝜀 >1.4 𝜀
Quantative
EROA (mm²) <20 20-29 30-39 ≥40
R Vol (mL) <30 30-44 45-59 ≥60
RF (%) <30 30-39 40-49 ≥50
Structural parameters
LV and LA size Usually normal Normal or dilated Usually dilated Usually dilated
PA pressure Usually normal Normal or elevated Normal or elevated Usually elevated
Grading severity mitral regurgitation

CW, continuous wave; EROA, effective regurgitant orifice area; LA, left atrium; LV left ventricle; MR, mitral regurgitation; PA pulmonary artery; RF, regurgitant fraction; R Vol regurgitant volume; VC, vena contracta.
𝛼 At Nyquist limit of 50-60 cm/s.
𝛽 For average between AP4Ch an AP2Ch.
𝛾 Unless other reasons, of systolic blunting (atrial fibrillation, elevated LA pressure).
𝛿 Usually after 50 years of age.
𝜀 In the absence of other causes of elevated LA pressure and of mitral stenosis.
𝜁 Different thresholds are used in secondary mitral regurgitation where an EROA >20mm² and regurgitant volume > 30mL identify a subset of patients at increased risk of cardiac events.

Echocardiographic criteria for the definition of severe mitral valve regurgitation: an integrative approuch

Parameter Criteria
Qualitative
Valve morphology Flail leaflet/ruptured pappilairy muscle/large coaptation defect
Colour flow regurgitant jet Very large central jet or eccentric jet adhering, swirling and reaching the posterior wall of the LA
CW signal of regurgitant jet Dense/triangular
Other Large flow convergence zone *
Semiquantitative
Vena contracta width (mm) ≥7 (>8 for biplane) **
Upstream vein flow Systolic pulmonary vein flow reversal
Inflow E-wave dominant ≥1.5 m/s ***
Other TVI mitral/TVI aortic >1.4
Quantative Primary Secundary ****
EROA (mm²) ≥40 ≥20
Regugitant volume (mL/beat) ≥60 ≥30
Enlargement of cardiac chamber/vessels LV, LA  

* At Nyquist limit of 50-60 cm/s.
** For average between AP4Ch an AP2Ch.
*** In the absence of other causes of elevated LA pressure and of mitral stenosis.
**** Different thresholds are used in secondary mitral regurgitation where an EROA >20mm² and regurgitant volume > 30mL identify a subset of patients at increased risk of cardiac events.

Severe MR because of prolaps
Severe MR because of prolaps

Causes of mitral valve regurgitation

Annulus dilation Degeneracy Acquired valve deviation Secundary
Atriumfibrillation Malcaptation in mitral valve stenosis Billowing Rhythm disorders (LBBB-->diastolic MR)
LV dilation   Prolaps SAM in HCM
LA dilation   Floppy valve  
    Flail leaflet  
    Chordal rupture  
    Ruptured Papillary muscle  

Ruptured mitral chordae tendineae assessed with 3D TEE
Ruptured mitral chordae tendineae assessed with 3D TEE

Stenosis

Quantification of mitral stenosis

Mild Moderate Severe  
MVA (cm²) > 1.5 1.5 - 1.0 < 1.0
PGmean (mmHg) < 5 5 - 10 > 10
PHT (m/s) < 90 90 - 150 > 150

Causes of mitral stenosis

Acquired Tumor Congenital
Degeneracy Myxoma Parachute valve
Rheumatic fever   Cor triatriatum sinistrum

The information above comes from Echocardiografie.nl. Last changed on: 7 September 2023.