1. Echocardiographic assessment of stenotic valvular lesions
Dr Nithin P G

2. Layout of seminar Basic considerations
Volumetric flow calculations
Continuity equation
Bernoulli equation & Pressure Gradients
Pressure Half Time & Deceleration time
Proximal Isovelocity Surface Area method
Assessment of common stenotic lesions MS AS TS PS

3. Basic consideration

4. Volumetric flow calculations
D (h) = v x t
D (h) =
D (h) =
Area under curve= VTI
Q= Cross sectional Area x VTI

5. Volumetric flow calculations
Limitations
Assumptions
Flow through rigid circular tube [elastic]
Uniform velocity across the vessel
Derived CSA is circular [AV valves elliptical]
CSA constant throughout the flow
SV remains in constant position throughout
Errors in VTI measurements
Inadequate beam alignment
Failure to correctly trace the VTI [ leading edge in A,P modal velocity in M,T]
3-5 beats in SR, bts in AF
Incorrect gain settings and filter settings
Errors in diameter measurements
Wrong phase of cardiac cycle
Inconsistent annulus measurement

6. Continuity equation QLVOT= Qthru all chambers
ALVOT x VTILVOT = Apoint x VTIpoint
Apoint = ALVOT x VTILVOT
VTIpoint
= p D2 x VTILVOT
VTIpoint
= D2 x VTILVOT
No intracardiac shunts between the two points
No significant regurgitant flow

7. Continuity equation Limitations Limitations in measurement of flow
Intracardiac shunts
Regurgitation flow
Low cardiac output

8. P1, v1 Bernoulli equation P2, v2 D P= 4V2
Peak Pressure Grad = 4 x (Vmax)2
Mean PG = 4 x (∑V1²+V2²+…Vn²) n
MPG=[∆P(max)/1.45 ]+2
MPG=2.4(Vmax)²

9. Bernoulli equation & Pressure Gradients

10. Bernoulli equation & Pressure Gradients
Pressure recovery phenomenon

11. Bernoulli equation & Pressure Gradients

12. Bernoulli equation & Pressure Gradients
HR=72
HR=100

13. Pressure Half Time & Deceleration time

14. Pressure Half Time & Deceleration time
PHT- time required by the pressure to decay to half its original value [ velocity to V/1.414]
MVA= 220/PHT
DT- Time taken for peak early diastolic velocity to fall to zero [ PHT= 0.29 x DT]
MVA= 759/DT

15. Pressure Half Time & Deceleration time
Advantages
Not affected by low cardiac output
Not affected by coexisting MR
Limitations
Affected by LV compliance, Peak Pressure gradients
Post BMV
Severe AR [elev. LVEDP shortens PHT]
Severe LVH- ↓LV compliance
Misinterpretation b/w AR velocity and MS signal [ MS after IVRT]
Prosthetic mitral valve- not validated

16. Proximal Isovelocity Surface Area method
QAlias= AAlias x VAlias
QAlias= 2pr2 x VN
QAlias= QOrif = AOrif x VOrif
AOrif = 2pr2 x VN
VOrif
Stenotic orifice area

17. Proximal Isovelocity Surface Area method
Angle correction
Flow can only converge from an angle of a
Corrected Formulae
MVA= 2pr2 x VN x a
Vorif

18. Proximal Isovelocity Surface Area method
Advantages
Mitral valve calcification
MR/AR
Accurate and reliable
Disadvantages
Peak velocity (E) rather than integration of flow over the entire diastolic period
Vena contracta= effective orifice area < anatomical orifice
Radius measurement calculation
Accurate measurement required
Low Aliasing velocity will reduce accuracy

19. Assessment of Common stenotic lesions

20. Mitral Stenosis

21. Mitral Stenosis RHD Commissural fusion⇒doming/bowing
Chordal thickening ⇒ abnormal motion
Progressive fibrosis⇒stiffening ⇒calcification
Doming of the mitral valve (hockey stick AML)
Funnel shaped opening of mitral valves
Focal thickening and beading of leaflets
Calcification

22. M-mode assessment
Increased echoes from thickened, deformed, calcified leaflets
Decreased opening amplitude of the valve
Anterior motion of the posterior leaflet
Decrease in the initial diastolic leaflet closure (E-F slope) [>80mm/s⇒MVA =4-6cm², <15mm/s⇒MVA <1.3cm²]
Left atrial enlargement is usually also readily apparent on M-mode
Mitral valve annular calcification can also be detected on M-mode
Decrease in the initial diastolic leaflet closure (E-F slope) [>80mm/s⇒MVA =4-6cm², <15mm/s⇒MVA <1.3cm²]

23. Severity of MS
The normal adult mitral valve area (MVA) is 4 to 6 cm² in CSA
Severe MS when,
MVA of < 1.0 cm²- severe MS
PHT> 220
Mean Gradient >10
Mild Moderate Severe

24. Assessment of severity
I. 2D-Planimetry
2D short axis imaging of diastolic orifice-planimetry
Smallest orifice at the leaflet tips
Inner edge of the black/white interface traced
Correlates well with hemodynamic assessment

25. Assessment of severity
Funnel-shaped- Actual limiting orifice at the tip
Instrumentation setting- ‘’blooming” of the echoes due to increased gain [operator—dependent]
Proper alignment of the imaging plane relative to valve orifice is critical
The orifice should be measured during initial diastole when the valve is maximally distended
Appropriate receiver gain settings are necessary
The orifice should appear fish mouthed
Good lateral resolution is necessary to identify the medial and lateral margins correctly.
Planimetry has decreased accuracy in the setting of valvular thickening and calcification, chest deformity and previous commissurotomy

27. Assessment of severity
Method for determining the correct level for planimetry
Step 1- Direct the scan plane to the level of papillary muscle
Step 2- Angle the transducer slightly medially & tilt superiorly until the tips of
mitral leaflets are identified [ corres. to the smallest MVA]
Step 3- Freeze the image in early diastole
Step 4- Trace the MVA along the inner margins of the leaflets

28. Assessment of severity
II. PHT or DT
Method for calculating the MVA by PHT & DT
Step 1- Optimize the CW Doppler Signal through the mitral valve
[usually the best from apical window, colour flow imaging]
Step 2- Measure the peak E velocity [Vpeak]
Step 3- Determine the PHT point on the EF slope where V becomes Vpeak / 1.414
Step 4- Draw vertical lines from baseline to Vpeak & PHT point
Step 5- Measure the time interval between the vertical lines [= PHT]
Step 6- Trace the EF slope till it touches the baseline, measure the time interval
from Vpeak to this point [=DT]
Step 7- Calculate MVA [220/PHT or 759/DT]

29. Assessment of severity
PHT or DT Tracing
A normal range of PHT is 20 – 60msec
MS have PHT > 90msec

30. Assessment of severity
III. PISA
Method for calculating the MVA by PISA
Step 1- Zoom the area of the mitral valve from the apical four-chamber view.
Step 2- Use colour flow imaging of the mitral stenosis jet and upward shift of the
zero baseline for colour map (30- to 45-cm/s aliasing velocity).
Step 3- Freeze colour flow images in a cine loop and identify an optimal frame to
measure radius (r) of PISA in the LA.
Step 4- Determine the angle (a) between two mitral leaflets at the atrial surface
and use the following formula:
MVA= 2pr2 x VN x a
Vpeak

31. Assessment of severity
Adjusting Aliasing velocity

32. Assessment of severity
IV. Continuity Equation
Method for calculating the MVA by Continuity Equation
Step 1-Measure the CSA in cm2 of LVOT [ from PLAX view measure the LVOT Dia.,
during systole, inner edge to inner edge; CSA= x D2]
Step 2- Measure VTI of LVOT [ from A5C view, PW doppler, SV just proximal to
aortic valve, systole, trace leading edge velocity for VTI ]
Step 3- Measure VTI of MS [from A4C view, CW doppler, trace modal velocity VTI]
Step 4- Calculate MVA using the following formula:
CSALVOT x VTILVOT
VTIMS

33. Assessment of severity
V. Pressure Gradients
Method for calculating the MV Gradients
Step 1-Optimize the CW Doppler Signal through the mitral valve
[usually the best from apical window, colour flow imaging]
Step 2- Measure the peak E velocity [Vpeak]. Peak PG= 4 Vpeak2
Step 3- Trace the velocity signal of MS to get the mean PG.
Step 4- Mention the heart rate at which measurement taken

34. Assessment of severity
TECHNIQUE
METHOD
REMARKS
Planimetry
Measurement in short axis view
Operator dependent, decreased accuracy in setting of calcification or prev. commisurotomy
Pressure half time (Pt½ )
MVA= 220/ Pt½ where Pt½ =0.29 x Deceleration time
Unreliable in conditions with elevated LVEDP (MR, AI, recent PBMV)
Continuity Equation
MVA=D2 LVOT x 0.785x TVI LVOT /TVI MV
In regurgitant lesions reliability decreases
PISA (Proximal Iso -velocity Surface Area)
MVA= 2πr2 x V
Very reliable, operator dependent

35. Secondary features of MS
LA dilation AF
Spontaneous echo contrast
LA thrombus
Secondary pulmonary HTN-TR

36. Echo approach to MS Valve morphology, etiology
Exclude other causes of clinical presentation
MS severity
Peak & Mean PG
2D valve area
MVA by PHT, Continuity, PISA
Assosiated MR
LA enlargement/ clots
Pulmonary art pressure
Co-existing TR severity
Assessment for BMV

37. Individuals with score≤8 –excellent for BMV
Those with score≧12-less satisfactory results

39. Tricuspid Stenosis
Normal inflow velocity < 0.5-1m/sec, mean gradient < 2 mm Hg.
Respiratory variation in inflow velocity [ increased during inspiration]. Best measured with breath held in expiration
2D-Planimetry cannot be used
Severe when mean PG > 7 mm Hg or PHT > 190 msec

40. AORTIC VALVE
Trileaflet valve Normal valve area-3-4 cm² Severity of Aortic Stenosis
Mild Moderate Severe

41. AVA-Direct planimetry
Rarely are all 3 leaflets imaged perpendicular
Triangular shape- measurement error
Deformities & irregularities- further exacerbates
AoV- superior-inferior rapid moments

42. Assessment of severity
I. Continuity Equation
Method for calculating the MVA by Continuity Equation
Step 1-Measure the CSA in cm2 of LVOT [ from PLAX view measure the LVOT Dia.,
during systole, inner edge to inner edge; CSA= x D2]
Step 2- Measure VTI of LVOT [ from A5C view, PW doppler, SV just proximal to
aortic valve, systole, trace leading edge velocity for VTI ]
Step 3- Measure VTI of AS [from multiple views , A5C view, CW doppler, trace
modal velocity VTI]
Step 4- Calculate MVA using the following formula:
CSALVOT x VTILVOT
VTIAS

43. Assessment of severity
II. Pressure Gradients
Method for calculating the Pressure Gradients
Step 1-Optimize the CW Doppler Signal through the aortic valve
[usually from apical 5C window, colour flow imaging]
Step 2- Measure the peak velocity [Vpeak]. Peak PG= 4 Vpeak2
Step 3- Trace the velocity signal of AS to get the mean PG.
Step 4- Mention the heart rate at which measurement taken

44. Assessment of Severity
Discrepancies
Technically poor doppler recording
Non parallel interrogation angle
Pressure gradients depends on HR, flow rate & valve narrowing –AR/LV dysfunction

45. Assessment of Severity
Dobutamine Echo
Aortic valve area depends on Aortic flow rate
Distinguish- true severe valvular stenosis vs mild to mod stenosis with LV dysfunction
Stepwise infusion of dobutamine(5—30µg/kg/min)
Lack of contractile reserve-
Failure of LVEF to ↑ by 20% is a poor prognostic sign

46. Normal LV , AS
Abnormal LV , AS

47. Assessment of Severity
Maximal aortic cusp separation (MACS) on M-mode
Vertical distance between RCC and NCC during systole
Stenotic Aortic Valve → decreased MACS
Limitations
Single dimension
Asymmetrical AV involvement
Calcification / thickness
↓ LV systolic function
↓ CO status
AVA
MACS
N > 2cm2
N > 15 mm
< cm2
< 8 mm
> 1 cm2
> 12 mm
gray area
8 – 12 mm

48. Assessment of Severity
Ao valve resistance-
Has a good correlation with AVA for a given aortic velocity.
Resistance=28/ AVA x √gradient( mean)
=(∆P/∆Q)mean x1333
Dimensionless index [DI]
DI =VTILVOT / VTIAortic
If DI < 0.25 for native valve, then critical stenosis

49. Discrepancies in AS severity assessment
AS by gradient
Gradient lower than expected
Reduced EF
Significant MR
Gradient higher than expected
Significant AR
High Output states like anemia, fever
AS by continuity Equation
Associated subvalvular obstruction [higher LVOT velocities, abnormal measurements]; [AR not C.I.]
LVOT TVI- SV -just behind AoV
Suboptimal LVOT measurements
Low Trans Aortic flow rate
Low EF
Small ventricular chamber
Mod-severe MR

50. Echo approach to AS Valve anatomy, etiology Exclude other LVOTO
Stenosis severity
jet velocity
mean pressure gradient
AVA – continuity equation LV
Dimensions/ hypertrophy/ EF/ diastolic fn
Aorta
Aortic diameter/ annulus diameter/ assess COA
AR – quantification if more than mild
Associated MR- mechanism & severity
Pulmonary artery pressure

51. Pulmonary stenosis
Isolated or associated with other congenital lesions
Jet velocity > 4 m/sec or maximum gradient > 60 mm Hg
Prominent a waves in M-mode tracing
P V Pressure gradient
A wave amplitude
Nil
2-7 mm
< 50 mm Hg
2-10 (6) mm
>50 mm Hg
6-18 (10) mm

52. Thank you