Quantification of Mitral Stenosis:

Planimetry, pressure Half time, Continuity Common Errors

Christopher J Kramer RDCSAdvanced Cardiovascular Services

Aurora Health CareMilwaukee, WI

• No Disclosures

Baumgartner, H., et al JASE January 2009

How to Grade Mitral Stenosis

• Routine evaluation of MS severity should combine:

• Mean Gradient and Valve area using Planimetry and Pressure 1/2t methods.

• In case of discrepancy the result of planimetry is the reference measurement, except with poor acoustic windows.

• Continuity equation or PISA not recommended for routine use but may be useful in certain patients when standard measurements are inconclusive.

Quantification Methods

• Valve Area• Planimetry • Pressure Half Time (PHT)• Continuity Equation• Proximal Isovelocity Surface Area (PISA)

• Mean Gradient

Recommended Recordings Mitral Stenosis

• Apical window• CW Doppler• PW Doppler

• Leaflet tips

• Use Color Doppler to line up with MV inflow jet

• Parallel to Flow• Parasternal short-axis MV level / long-

axis

Mitral Stenosis: Game Plan

Normal Sinus Rhythm and Rapid Atrial Fibrillation

Echocardiographic Quantification

Pathophysiology of MS

Right Heart

Failure

↑ RA Size

RV Hypertrophy

↑ RV Volume

Pulmonary

Edema

“Backward Failure”

into Right Heart

↑ LA Size

↑ LA Pressure

Narrowed MV

Orifice

Kinney MR & others: Comprehensive cardiac care, 7th ed. St. Louis, 1991, Mosby.

PulmonaryHypertension

Case #1

49 year old femaleHistory significant for rheumatic feverVitals – 72 bpm– Sinus rhythm– BP 132/80– Grade 1/6 diastolic rumble

Planimetry

Minimum Diameter = 1.2cm

Planimetry

Minimum Diameter = 1.2cm

Planimetry

Planimetry

Area = 1.8cm2

Mitral StenosisSeverity Guidelines

Severity Mean Gradient MVA (cm2) PHT(msec)

Mild < 4 mmHg > 1.5 <150 Moderate 5 - 9 mmHg 1.1 - 1.5 150- 219 Severe > 10 mmHg < 1.0 > 220

Pressure Half Time

Pressure Half Time

V1 0.7V1PHT

Time for the pressure to drop in halfVelocity

Time

MV PHT= 120ms

MVA= 1.8cm2

Mitral StenosisSeverity Guidelines

Severity Mean Gradient MVA (cm2) PHT(msec)

Mild < 4 mmHg > 1.5 <150 Moderate 5 - 9 mmHg 1.1 - 1.5 150- 219 Severe > 10 mmHg < 1.0 > 220

Continuity Equation

X MVA

SV

CP935823-29

MVA= LVOTSV/MVTVI

LVOTTVI= 25cm

Continuity Equation

LVOT= 2.1cm

Continuity EquationMVPeak=1.5m/s

MVTVI= 52cm

Continuity Equation

LVOTTVI= 25cm

LVOT= 2.1cm

MVTVI= 52cm

x x.785( )2

=1.7cm2

Mitral StenosisSeverity Guidelines

Severity Mean Gradient MVA (cm2) PHT(msec)

Mild < 4 mmHg > 1.5 <150 Moderate 5 - 9 mmHg 1.1 - 1.5 150- 219 Severe > 10 mmHg < 1.0 > 220

Vp

θrVa

PISA

MVA = 6.28 x r2 x Aliasing velocity x θ MV peak velocity 180

Rifkin RD et al. JACC 1995

PISA

PISA

MVA = 6.28 x (1.1cm)2 x (39cm/s) x 150 150cm/s 180

θ=150o

=1.6cm2

Mitral StenosisSeverity Guidelines

Severity Mean Gradient MVA (cm2) PHT(msec)

Mild < 4 mmHg > 1.5 <150 Moderate 5 - 9 mmHg 1.1 - 1.5 150- 219 Severe > 10 mmHg < 1.0 > 220

Mean Pressure GradientMVPeak=1.5m/s

MVMean= 4mmHg

Mitral StenosisSeverity Guidelines

Severity Mean Gradient MVA (cm2) PHT(msec)

Mild < 4 mmHg > 1.5 <150 Moderate 5 - 9 mmHg 1.1 - 1.5 150- 219 Severe > 10 mmHg < 1.0 > 220

Case #1Quantification

– PlanimetryMVA= 1.8cm2

Mild MS

– PHTMVA= 1.8cm2

Mild MS

– Continuity Equation

MVA= 1.7cm2

Mild MS

– PISAMVA= 1.6cm2

Mild MS

– Mean GradientMild MS

Case #2

69 year old femaleHistory significant for Rheumatic feverVitals – 110bpm– Atrial fibrillation– BP 140/84

Planimetry

Planimetry

Planimetry

Minimum

Diameter= .85cm Area=1.2cm2

Pressure Half Time

Pressure Half Time

MVPV=2.4m/s

PHT=188ms

MVA=1.2cm2

MVPV=2.2m/s

PHT=177ms

MVA=1.2cm2

MVPV=2.2m/s

PHT=196ms

MVA=1.1cm2

MVPV=2.6m/s

PHT=186ms

MVA=1.2cm2

MVPV=2.6m/s

PHT=185ms

MVA=1.2cm2

MVPV=2.6m/s

PHT=191ms

MVA=1.2cm2

Average MVAPHT=1.2cm2

LVOTDiam=1.9cm

Continuity Equation

PV=1.3m/s

TVI=20cm

PV=1.3m/s

TVI=20cm

PV=1.2m/s

TVI=18cmAverage TVI=19cm

Continuity Equation

MVPV=2.4m/s

MnGr=14mmHg

MVTVI=34cm

MVPV=2.2m/s

MnGr=11mmHg

MVTVI=43cm

MVPV=2.2m/s

MnGr=11mmHg

MVTVI=69cm

MVPV=2.6m/s

MnGr=16mmHg

MVTVI=52cm

MVPV=2.6m/s

MnGr=15mmHg

MVTVI=70cm

MVPV=2.6m/s

MnGr=12mmHg

MVTVI=68cm

Average MVTVI=56cm

Continuity Equation

MVA=(1.9cm)2 x .785 x 19

56cm

=.96cm2

PISA

PISA1.1cm

θ=165o

PISA

MVA = 6.28 x (1.1cm)2 x (34cm/s) x165 240cm/s 180

=.99cm2

MVPV=2.4m/s

MnGr=14mmHg

MVTVI=34cm

MVPV=2.2m/s

MnGr=11mmHg

MVTVI=43cm

MVPV=2.2m/s

MnGr=11mmHg

MVTVI=69cm

MVPV=2.6m/s

MnGr=16mmHg

MVTVI=52cm

MVPV=2.6m/s

MnGr=15mmHg

MVTVI=70cm

MVPV=2.6m/s

MnGr=12mmHg

MVTVI=68cm

Mean Pressure Gradient

Average Mean Gradient=13mmHg

Mitral StenosisSeverity Guidelines

Severity Mean Gradient MVA (cm2) PHT(msec) Mild < 4 mmHg > 1.5 <150 Moderate 5 - 9 mmHg 1.1 - 1.5 150- 219 Severe > 10 mmHg < 1.0 > 220

NOTE:Heart rate dependent!

Case# 2Quantification– Planimitery

MVA=1.2cm2

Moderate MS

– PHTMVA=1.2cm2

Moderate MS

– Continuity Equation

MVA=.96cm2

Severe MS

– PISAMVA=.99cm2

Severe MS

– Mean GradientMean PG=13mmHgSevere MS

Indicators

LA Volume (ml/m2)RVSPRV SizeRV Function

Average TR Velocity=3.4m/s

MV 3D

MV 3DQ

Take Home Points

• Use all tools in your toolbox, Mean Gradient, MVA; P1/2 time, Planimetry

• Know your limitations of MS• Always record the HR when reporting

the mean pressure gradient • Measure a minimum of 5 beats when

atrial fibrillation is present• Incorporate the supportive indicators

when determining the severity of stenosis