Echo Conference April 6, 2011 Frances Canet, MD. Causes and Anatomy Assessment of Mitral Stenosis...
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Transcript of Echo Conference April 6, 2011 Frances Canet, MD. Causes and Anatomy Assessment of Mitral Stenosis...
Echo Conference
April 6, 2011
Frances Canet, MD
• Causes and Anatomy
• Assessment of Mitral Stenosis
• How to Grade Mitral Stenosis
• Cases and Application
Outline
Rheumatic MSCommissural fusion
Degenerative MSAnnular calcificationAssociated with elderly, hypertension, atherosclerosis and aortic stenosis
Congenital MSAbnormalities of subvalvular apparatus
Other: Systemic lupus, infiltrative disease, carcinoid heart disease, drug-induced valve disease
Causes and Anatomy
Level 1 Recommendations:
Pressure gradient
MVA Planimetry
Pressure half-time
Level 2 Recommendations:
Continuity equation
Proximal isovelocity surface area method (PISA)
Stress echocardiography
How to Assess Mitral Stenosis
Continuous wave doppler is preferred
Gradient is measured in the apical window
Color doppler is used to identify eccentric diastolic mitral jets
Doppler beam is guided by the highest flow velocity zone identified by color doppler
Mean gradient is the relevant hemodynamic finding
Measure heart rate at which gradients are obtained
If patient is in atrial fibrillation, the mean gradient should be an average of five cycles with the least variation of R-R intervals
Pressure Gradient
Mitral Valve Area Planimetry
Direct tracing of the mitral orifice including opened commissures in the parasternal short-axis view at mid-diastoleAdvantages: -Direct measure of MVA-Does not involve hypothesis regarding flow conditions, cardiac chamber compliance or associated valvular lesions-Best correlation with anatomic valve area of explanted valves
Obtaining and measuring the image:
-Scan apex to the base of the LV to ensure the cross-sectional area is measured at the leaflet tips.
-Plane should be perpendicular to the mitral orifice, elliptical shape.
-Gain, sufficient to see contour of the mitral orifice.- If too excessive, may cause under estimation of the valve
area.
-Perform several measurements if the patient has atrial fibrillation or incomplete commissural fusion
Mitral Valve Area Planimetry
T1/2 = time interval in milliseconds between the maximum mitral gradient in early diastole and the time point where the gradient is half the maximum initial value
MVA = 220/ T1/2
Pressure half-time
Measuring T1/2 with a bimodal, non-linear decreasing slope of the E-wave
Based on assumption that the filling volume of diastolic mitral flow is equal to aortic SV.
MVA = pi (D2/4) (VTIAortic / VTIMitral)
D is the diameter of the LVOT in cm
VTI is in cm.
Accuracy and reproducibility is hampered by the number of measurements increasing the impact of errors of measurements.
Cannot be used in atrial fibrillation or associated significant MR or AR
Continuity equation – Level 2
MVA = pi (r2) (Valiasing) / Peak Vmitral x alpha/1800
R is the radius of the convergence hemisphere in cm
Valiasing is the aliasing velocity in cm/s
Peak Vmitral is the peak CWD velocity of mitral inflow in cm/s
alpha is the opening angle of mitral leaflets relative to flow direction
Proximal isovelocity surface area method – Level 2
Parasternal short-axis view
valve thickness (maximum and heterogeneity)
commissural fusion
extension and location of localized bright zones (fibrous nodules or calcification)
Parasternal long-axis view
valve thickness
extension of calcification
valve pliability
subvalvular apparatus (chordal thickening, fusion, or shortening)
Apical two-chamber view
subvalvular apparatus (chordal thickening, fusion, or shortening)
Detail each component and summarize in a score
Valve Anatomy
Enables measurement of mean mitral gradient and systolic pulmonary artery pressure during effort.
Semi-supine exercise echocardiography allows monitoring of gradient.
Useful in patients with equivocal or discordant with the severity of MS.
Stress Echocardiography – Level 2
How to Grade Mitral Stenosis
Normal MVA is 4.0-5.0 cm2 MVA >1.5 cm2 does not produce symptomsAs severity increases, cardiac output decreases and fails to increase during exercise.
Grades morphological changes in the MV during echo:
Leaflet mobility
Leaflet thickening
Valve calcification
Involvement of the subvalvular apparatus
Each characteristic is graded from 0-4, with a total of 16 points total.
A score >8 is predictive of low success post percutaneous mitral valvuloplasty.
Wilkins (Valvotomy )Score
72-year-old man with known moderate aortic stenosis, mitral regurgitation, hypertension, diabetes, COPD, TIA and severe pulmonary hypertension based on cardiac catheterization results is referred for echocardiogram to assess severity of mitral valve regurgitation.
How severe is his mitral regurgitation? Does he have mitral stenosis? What are his options for repair – calculate valvotomy score?
Case 1
PSL MV
PSL Zoom
PSL MV Color
4C AP
4C AP Color
MV Planimetry
PSS MV Planimetry Still
MV VTI for Pressure Gradient
MV half time 3
LVOT Diameter is 2.1
VTI aortic is 87
VTI mitral is 87.2
MVA = pi (D2/4) (VTIAortic / VTIMitral)
MVA = 3.89 cm2 (Not accurate compared to MVA of 1.15 cm2 calculated from pressure gradient. Remember, it is not accurate in patient with severe mitral regurgitation or atrial fibrillation.)
Less accurate calculation of MVA as it relies on several other measurements to be accurate.
Continuity equation
Valvotomy Score = 12Mobility – valve moves forward in diastole, moves mainly from base3 points
Subvalvular Thickening – thickening of chordal structures extending into 1/3rd of the chordal length 3 points
Thickening – extends through the entire leaflet3 points
Calcification – Brightness extending into the mid-portion of the leaflets3 points
Total score = 12
56-year-old woman with a history of rheumatic mitral valve stenosis, respiratory failure, heart failure, atrial fibrillation, recent stroke, COPD, sarcoidosis, schizophrenia was transferred from an outside hospital for a second opinion on mitral valve replacement. She has poor functional and neurologic status at present.
Evaluate the grade of her mitral stenosis and calculate her valvotomy score.
Case 2
PSL MV
PSL MV Zoom
PSL MV Color
4C AP MV
PSS Planimetry Loop
Planimetry Still
This is not acutally the area of the MV orfiice. Look at the small sliver of black area just below the tracing.
Pressure gradient
Pressure half-time
Resting mean pressure gradient: 16mmHg (severe is >10mmHg)
Mitral valve area using half time: 0.77cm2 (severe is <1.0 cm2 )
PHT: 285 ms (severe is greater than 220ms)
Grade of mitral stenosis: Severe
Valvotomy score:
Mobility: 4 – No or minimal forward movement of the leaflets.
Subvalvular Thickening: 2-3-
Thickening of chordal structures up to one-third of the chordal length possibly to distal third of the chords.
Thickening: 4 – Considerable thickening of all leaflet tissue (>8-10mm).
Calcification: 4 – Extensive brightness throughout much of the leaflet tissue.
Valvotomy score: 14 out of 16