Quantification of Mitral Stenosis: Planimetry, pressure Half time, Continuity Common Errors Christopher J Kramer RDCS Advanced Cardiovascular Services Aurora Health Care Milwaukee, 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 / longaxis Mitral Stenosis: Game Plan Normal Sinus Rhythm and Rapid Atrial Fibrillation Echocardiographic Quantification Pathophysiology of MS Narrowed MV Orifice LA Pressure Right Heart Failure RA Size RV Hypertrophy LA Size Backward Failure into Right Heart Pulmonary Edema RV Volume Pulmonary Hypertension Kinney MR & others: Comprehensive cardiac care, 7th ed. St. Louis, 1991, Mosby.
Case #1 49 year old female History significant for rheumatic fever Vitals 72 bpm Sinus rhythm BP 132/80 Grade 1/6 diastolic rumble Planimetry Planimetry Minimum Diameter = 1.2cm Planimetry Minimum Diameter = 1.2cm
Planimetry Area = 1.8cm 2 Mitral Stenosis Severity Guidelines Severity Mean Gradient MVA (cm 2 ) 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 MV PHT= 120ms MVA= 1.8cm 2 Velocity V 1 PHT 0.7V 1 Time Time for the pressure to drop in half
Mitral Stenosis Severity Guidelines Severity Mean Gradient MVA (cm 2 ) 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 SV X MVA MVA= LVOT SV /MV TVI CP935823-29 Continuity Equation LVOT= 2.1cm LVOT TVI = 25cm Continuity Equation MV Peak =1.5m/s MV TVI = 52cm
( Continuity Equation )2 LVOT TVI = 2.1cm x.785 x 25cm LVOT= MV TVI = 52cm =1.7cm 2 Mitral Stenosis Severity Guidelines Severity Mean Gradient MVA (cm 2 ) PHT(msec) Mild < 4 mmhg > 1.5 <150 Moderate 5-9 mmhg 1.1-1.5 150-219 Severe > 10 mmhg < 1.0 > 220 θ V a PISA r MVA = 6.28 x r 2 x Aliasing velocity x θ MV peak velocity 180 V p Rifkin RD et al. JACC 1995 PISA
PISA θ=150 o MVA = 6.28 x (1.1cm) 2 x (39cm/s) x 150 150cm/s 180 =1.6cm 2 Mitral Stenosis Severity Guidelines Severity Mean Gradient MVA (cm 2 ) 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 Gradient MV Peak =1.5m/s MV Mean = 4mmHg Mitral Stenosis Severity Guidelines Severity Mean Gradient MVA (cm 2 ) PHT(msec) Mild < 4 mmhg > 1.5 <150 Moderate 5-9 mmhg 1.1-1.5 150-219 Severe > 10 mmhg < 1.0 > 220
Quantification Case #1 Planimetry PHT MVA= 1.8cm 2 Mild MS MVA= 1.8cm 2 Mild MS Continuity Equation MVA= 1.7cm 2 PISA MVA= 1.6cm 2 Mild MS Mean Gradient Mild MS Mild MS Case #2 69 year old female History significant for Rheumatic fever Vitals 110bpm Atrial fibrillation BP 140/84 Planimetry Planimetry
Planimetry Minimum Area=1.2cm2 Diameter=.85cm Pressure Half Time Pressure Half Time MVPV=2.4m/s MVPV=2.2m/s MVPV=2.2m/s MVPV=2.6m/s MVPV=2.6m/s MVPV=2.6m/s PHT=188ms PHT=177ms PHT=196ms PHT=186ms PHT=185ms PHT=191ms MVA=1.2cm2 MVA=1.2cm2 MVA=1.1cm2 MVA=1.2cm2 MVA=1.2cm2 MVA=1.2cm2 Average MVAPHT=1.2cm2 Continuity Equation LVOTDiam=1.9cm PV=1.3m/s PV=1.2m/s PV=1.3m/s AverageTVI=18cm TVI=19cm TVI=20cm TVI=20cm
Continuity Equation MV PV =2.4m/s MV PV =2.2m/s MV PV =2.2m/s MV PV =2.6m/s MV PV =2.6m/s MV PV =2.6m/s MnGr=14mmHg MnGr=11mmHg MnGr=11mmHg MnGr=16mmHg MnGr=15mmHg MnGr=12mmHg MV TVI =34cm MV TVI =43cm MV TVI =69cm MV TVI =52cm MV TVI =70cm MV TVI =68cm Average MV TVI =56cm Continuity Equation MVA= (1.9cm) 2 x.785 x 19 56cm =.96cm 2 PISA PISA 1.1cm θ=165 o
PISA MVA = 6.28 x (1.1cm) 2 x (34cm/s) x165 240cm/s 180 =.99cm 2 Mean Pressure Gradient MV PV =2.4m/s MV PV =2.2m/s MV PV =2.2m/s MV PV =2.6m/s MV PV =2.6m/s MV PV =2.6m/s MnGr=14mmHg MnGr=11mmHg MnGr=11mmHg MnGr=16mmHg MnGr=15mmHg MnGr=12mmHg MV TVI =34cm MV TVI =43cm MV TVI =69cm MV TVI =52cm MV TVI =70cm MV TVI =68cm Average Mean Gradient=13mmHg Mitral Stenosis Severity Guidelines Severity Mean Gradient MVA (cm 2 ) 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# 2 Quantification Planimitery PHT MVA=1.2cm 2 Moderate MS MVA=1.2cm 2 Moderate MS Continuity Equation MVA=.96cm 2 Severe MS PISA MVA=.99cm 2 Severe MS Mean Gradient Mean PG=13mmHg Severe MS
Indicators LA Volume (ml/m2) RVSP RV Size RV 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