1. ECHOCARDIOGRAPHIC ASSESSMENT OF AORTIC VALVE STENOSIS
Dr Ranjith MP

2. Normal Aortic valve Three cusps, crescent shaped 3 commissures
3 sinuses
supported by fibrous annulus
3.0 to 4.0 cm2
Node of Arantius

3. 2D Echo-Long axis view
Diastole
Systole

4. Y or inverted Mercedes-Benz sign
2D Echo-Short axis view
Diastole
Systole
Y or inverted Mercedes-Benz sign

5. 2D - Apical five chamber view

6. 2D – Suprasternal view

7. M Mode- Normal aortic valve

8. CAUSES AND ANATOMIC PRESENTATION

9. Aortic stenosis- Causes
Most common :-
Bicuspid aortic valve with calcification
Senile or Degenerative calcific AS
Rheumatic AS
Less common:-
Congenital
Type 2 Hyperlipoproteinemia
Onchronosis

10. Anatomic evaluation
Combination of short and long axis images to identify
Number of leaflets
Describe leaf mobility, thickness, calcification
Combination of imaging and doppler allows the determination of the level of obstruction; subvalvular, valvular, or supravalvular.
Transesophageal echocardiography may be helpful when image quality is suboptimal.

11. Calcific Aortic Stenosis
Nodular calcific masses on aortic side of cusps
No commissural fusion
Free edges of cusps are not involved
stellate-shaped systolic orifice

12. Calcific Aortic Stenosis
Parasternal long axis view showing echogenic and immobile aortic valve

13. Calcific Aortic Stenosis
Parasternal short-axis view showing calcified aortic valve leaflets. Immobility of the cusps results in only a slit like aortic valve orifice in systole

14. Bicuspid Aortic valve
Fusion of the right and left coronary cusps (80%)
Fusion of the right and non-coronary cusps(20%) Schaefer BM et al. Am J Cardiol 2007;99:686– Schaefer BM et al.Heart 2008;94:1634–1638.

15. Bicuspid Aortic valve
Two cusps are seen in systole with only two commissures framing an elliptical systolic orifice(the fish mouth appearance).
Diastolic images may mimic a tricuspid valve when a raphe is present.

16. Bicuspid Aortic valve Parasternal long-axis echocardiogram may show
an asymmetric closure line
systolic doming
diastolic prolapse of the cusps
In children, valve may be stenotic
without extensive calcification.
In adults, stenosis typically is due to calcific changes, which often obscures the number of cusps, making determination of bicuspid vs. tricuspid valve difficult

17. Calcific Aortic Stenosis
Calcification of a bicuspid or tricuspid valve, the severity can be graded semi-quantitatively as
Schaefer BM et al.Heart 2008;94:1634–1638.
The degree of valve calcification is a predictor of clinical outcome Rosenhek R et al. N Engl J Med 2000;343:611–7.

18. Aortic sclerosis Thickened calcified cusps with preserved mobility
Typically associated with peak doppler velocity of less than 2.5 m/sec

19. Rheumatic aortic stenosis
Characterized by
Commissural fusion
Triangular systolic orifice
thickening & calcification
Accompanied by rheumatic mitral valve changes.

20. Rheumatic aortic stenosis
Parasternal short axis view showing commissural fusion, leaflet thickening and calcification, small triangular systolic orifice

21. Subvalvular aortic stenosis
(1) Thin discrete membrane consisting of endocardial fold and fibrous tissue (2) A fibromuscular ridge (3) Diffuse tunnel-like narrowing of the LVOT (4) accessory or anomalous mitral valve tissue.
Long axis view in a patent with a subaortic membrane (arrow).

22. Supravalvular Aortic stenosis
Type I - Thick, fibrous ring above the aortic valve with less mobility and has the easily identifiable 'hourglass' appearance of the aorta.

23. Supravalvular Aortic stenosis
Type II - Thin, discrete fibrous membrane located above the aortic valve
The membrane usually mobile and may demonstrate doming during systole
Type III- Diffuse narrowing

24. HOW TO ASSESS AORTIC STENOSIS

25. Doppler assessment of AS
The primary haemodynamic parameters recommended (EAE/ASE Recommendations for Clinical Practice 2008)
Peak transvalvular velocity
Mean transvalvular gradient
Valve area by continuity equation.

26. Peak transvalvular velocity
Continuous-wave Doppler ultrasound
Multiple acoustic windows
Apical and suprasternal or right parasternal most frequently yield the highest velocity
rarely subcostal or supraclavicular windows may be required
Three or more beats are averaged in sinus rhythm, with irregular rhythms at least 5 consecutive beats

27. Peak transvalvular velocity
AS jet velocity is defined as the highest velocity signal obtained from any window after a careful examination
Any deviation from a parallel intercept angle results in velocity underestimation
The degree of underestimation is 5% or less if the intercept angle is within 15⁰ of parallel.
‘Angle correction’ should not be used because it is likely to introduce more error given the unpredictable jet direction.

28. Peak transvalvular velocity
The velocity scale adjusted so the spectral doppler signal fills on the vertical axis, and with a time scale on the x-axis of 100 mm/s
Wall filters are set at a high level and gain is decreased to optimize identification of the velocity curve.
Grey scale is used
A smooth velocity curve with a dense outer edge and clear maximum velocity should be recorded

29. Peak transvalvular velocity
The shape of the CW Doppler velocity curve is helpful in distinguishing the level and severity of obstruction.
With severe obstruction, maximum velocity occurs later in systole and the curve is more rounded in shape
With mild obstruction, the peak is in early systole with a triangular shape of the velocity curve

30. Peak transvalvular velocity
The shape of the CWD velocity curve also can be helpful in determining whether the obstruction is fixed or dynamic
Dynamic sub aortic obstruction shows a characteristic late peaking velocity curve, often with a concave upward curve in early systole

31. Mean transvalvular gradient
The difference in pressure between the left ventricle and aorta in systole
Gradients are calculated from velocity information
The relationship between peak and mean gradient depends on the shape of the velocity curve.

32. Mean transvalvular gradient
Bernoulli equations
ΔP =4v²
The maximum gradient is calculated from maximum velocity ΔP max =4v² max
The mean gradient is calculated by averaging the instantaneous gradients over the ejection period

33. Mean transvalvular gradient
The simplified Bernoulli equation assumes that the proximal velocity can be ignored
When the proximal velocity is over 1.5 m/s or the aortic velocity is ,3.0 m/s, the proximal velocity should be included in the Bernoulli equation ΔP max =4 (v² max- v2proximal)

34. Sources of error for pressure gradient calculations
Malalignment of jet and ultrasound beam.
Recording of MR jet

35. Sources of error for pressure gradient calculations
Neglect of an elevated proximal velocity.
Any underestimation of aortic velocity results in an even greater underestimation in gradients, due to the squared relationship between velocity and pressure difference
The accuracy of the Bernoulli equation to quantify AS pressure gradients is well established

36. Pressure recovery
The conversion of potential energy to kinetic energy across a narrowed valve results in a high velocity and a drop in pressure.
Distal to the orifice, flow decelerates again. Kinetic energy will be reconverted into potential energy with a corresponding increase in pressure, the so-called PR

37. Pressure recovery
Pressure recovery is greatest in stenosis with gradual distal widening
Aortic stenosis with its abrupt widening from the small orifice to the larger aorta has an unfavorable geometry for pressure recovery
PR= 4v²× 2EOA/AoA (1-EOA/AoA)

38. Comparing pressure gradients calculated from doppler velocities to pressures measured at cardiac catheterization.

39. Comparing pressure gradients calculated from doppler velocities to pressures measured at cardiac catheterization.
Currie PJ et al. Circulation 1985;71:

40. Aortic valve area Continuity equation

41. Aortic valve area Aortic valve area
Continuity equation concept that the stroke volume ejected through the LV outflow tract all passes through the stenotic orifice
AVA= CSA LVOT×VTILVOT / VTIAV
Calculation of continuity-equation valve area requires three measurements
AS jet velocity by CWD
LVOT diameter for calculation of a circular CSA
LVOT velocity recorded with pulsed Doppler.

42. Aortic valve area Continuity equation
LVOT diameter and velocity should be measured at the same distance from the aortic valve.
When the PW sample volume is optimally positioned, the recording shows a smooth velocity curve with a well-defined peak.

43. Aortic valve area Continuity equation
The VTI is measured by tracing the dense modal velocity throughout systole
LVOT diameter is measured from the inner edge to inner edge of the septal endocardium, and the anterior mitral leaflet in mid-systole

44. Aortic valve area-Continuity equation Level of Evidence
Well validated - clinical & experimental studies.
Zoghbi WA et al. Circulation 1986;73:452-9.
Oh JK et al. J Am Coll Cardiol 1988;11:
Measures the effective valve area, the weight of the evidence now supports the concept that effective, not anatomic, orifice area is the primary predictor of clinical outcome.
Baumgartner et al. J Am Society Echo 2009; 22,1 , 1-23.

45. Limitations of continuity-equation valve area
Intra- and interobserver variability
AS jet and LVOT velocity 3 to4%.
LVOT diameter 5% to 8%.
When sub aortic flow velocities are abnormal SV calculation at this site are not accurate
Sample volume placement near to septum or anterior mitral leaflet

46. Limitations of continuity-equation valve area
Observed changes in valve area with changes in flow rate
AS and normal LV function, the effects of flow rate are minimal
This effect may be significant in presence concurrent LV dysfunction.

47. Left ventricular systolic dysfunction
Low-flow low-gradient AS includes the following conditions:
Effective orifice area < 1.0 Cm2
LV ejection fraction < 40%
Mean pressure gradient < 30–40 mmHg
Severe AS and severely reduced LVEF represent 5% of AS patients
Vahanian A et al. Eur Heart J 2007;28:230–68.

48. Dobutamine stress Echo
Provides information on the changes in aortic velocity, mean gradient, and valve area as flow rate increases.
Measure of the contractile response to dobutamine
Helpful to differentiate two clinical situations
Severe AS causing LV systolic dysfunction
Moderate AS with another cause of LV dysfunction

49. Dobutamine stress Echo
A low dose starting at 2.5 or 5 ủg/kg/min with an incremental increase in the infusion every 3–5 min to a maximum dose of 10–20 ủg/kg/min
The infusion should be stopped as soon as
Positive result is obtained
Heart rate begins to rise more than 10–20 bpm over baseline or exceeds 100bpm

50. Dobutamine stress Echo
Role in decision-making in adults with AS is controversial and the findings recommend as reliable are
Stress findings of severe stenosis
AVA<1cm²
Jet velocity>4m/s
Mean gradient>40mm of Hg
Nishimura RA et al. Circulation 2002;106:
Lack of contractile reserve-
Failure of LVEF to ↑ by 20% is a poor prognostic sign
Monin JL et al. Circulation 2003;108:

51. Serial measurements
During follow-up any significant changes in results should be checked in detail:
Make sure that aortic jet velocity is recorded from the same window with the same quality (always report the window where highest velocities can be recorded).
when AVA changes, look for changes in the different components incorporated in the equation.
LVOT size rarely changes over time in adults.

52. Alternate measures of stenosis severity
(Level 2 EAE/ASE Recommendations )

53. Simplified continuity equation. AVA= CSA LVOT×VLVOT / VAV
Based on the concept that in native aortic valve stenosis the shape of the velocity curve in the outflow tract and aorta is similar so that the ratio of LVOT to aortic jet VTI is nearly identical to the ratio of the LVOT to aortic jet maximum velocity.
AVA= CSA LVOT×VLVOT / VAV
This method is less well accepted because results are more variable than using VTIs in the equation.

54. Velocity ratio
Another approach to reducing error related to LVOT diameter measurements is removing CSA from the simplified continuity equation.
This dimensionless velocity ratio expresses the size of the valvular effective area as a proportion of the CSA of the LVOT.
Velocity ratio= VLVOT/VAV
In the absence of valve stenosis, the velocity ratio approaches 1, with smaller numbers indicating more severe stenosis.

55. Aortic valve area -Planimetry
Planimetry may be an acceptable alternative when Doppler estimation of flow velocities is unreliable
Planimetry may be inaccurate when valve calcification causes shadows or reverberations limiting identification of the orifice
Doppler-derived mean-valve area correlated better with maximal anatomic area than with mean-anatomic area.
Marie Arsenault, et al. J. Am. Coll. Cardiol. 1998;32;

56. Aortic valve area - Planimetry

57. Experimental descriptors of stenosis severity
(Level 3 EAE/ASE Recommendations -not recommended for routine clinical use)

58. Valve resistance
Relatively flow-independent measure of stenosis severity
Depends on the ratio of mean pressure gradient and mean flow rate
Resistance = (ΔPmean /Qmean) × 1333
There is a close relationship between aortic valve resistance and valve area
The advantage over continuity equation not established

59. Left ventricular stroke work loss
Left ventricle expends work during systole to keep the aortic valve open and to eject blood into the aorta
SWL(%) = (100×ΔPmean)/ ΔPmean+SBP
A cutoff value more than 25% effectively discriminated between patients experiencing a good and poor outcome.
Kristian Wachtell. Euro Heart J.Suppl. (2008) 10 ( E), E16–E22

60. Energy loss index Damien Garcia.et al. Circulation. 2000;101:765-771.
Fluid energy loss across stenotic aortic valves is influenced by factors other than the valve effective orifice area .
An experimental model was designed to measure EOA and energy loss in 2 fixed stenoses and 7 bioprosthetic valves for different flow rates and 2 different aortic sizes (25 and 38 mm).
EOA and energy loss is influenced by both flow rate and AA and that the energy loss is systematically higher (15±2%) in the large aorta.
Damien Garcia.et al. Circulation. 2000;101:

61. Energy loss index Damien Garcia.et al. Circulation. 2000;101:765-771.
Energy loss coefficient (EOA × AA)/(AA - EOA) accurately predicted the energy loss in all situations .
It is more closely related to the increase in left ventricular workload than EOA.
To account for varying flow rates, the coefficient was indexed for body surface area in a retrospective study of 138 patients with moderate or severe aortic stenosis.
The energy loss index measured by Doppler echocardiography was superior to the EOA in predicting the end points
An energy loss index #0.52 cm2/m2 was the best predictor of diverse outcomes (positive predictive value of 67%).

62. Classification of AS severity (a ESC & bAHA/ACC Guidelines)
Aortic Sclerosis
Mild
Moderate
Severe
Aortic jet velocity (m/s)
≤ 2.5 m/s
> 4
Mean gradient (mm Hg)
< 20b(<30a)
20 – 40b (30 -50a)
> 40
AVA (cm²)
> 1.5
< 1.0
Indexed AVA (cm²/m²)
> 0.85
0.60 – 0.85
< 0.6
Velocity ratio
> 0.50
0.25 – 0.50
< 0.25

63. Effects of concurrent conditions on assessment of severity

64. Effect of concurrent conditions ……
Left ventricular systolic dysfunction
Left ventricular hypertrophy
Small ventricular cavity & small LV ejects a small SV so that, even in severe AS the AS velocity and mean gradient may be lower than expected.
Continuity-equation valve area is accurate in this situation

65. Effect of concurrent conditions contd…
Hypertension
35–45% of patients
primarily affect flow and gradients but less AVA measurements
Control of blood pressure is recommended
The echocardiographic report should always include a blood pressure measurement

66. Effect of concurrent conditions contd…
Aortic regurgitation
About 80% of adults with AS also have aortic regurgitation
High transaortic volume flow rate, maximum velocity, and mean gradient will be higher than expected for a given valve area
In this situation, reporting accurate quantitative data for the severity of both stenosis and regurgitation

67. Effect of concurrent conditions contd…
Mitral valve disease
With severe MR, transaortic flow rate may be low resulting in a low gradient .Valve area calculations remain accurate in this setting
A high-velocity MR jet may be mistaken for the AS jet. Timing of the signal is the most reliable way to distinguish

68. Effect of concurrent conditions contd…
High cardiac output
Relatively high gradients in the presence of mild or moderate AS
The shape of the CWD spectrum with a very early peak may help to quantify the severity correctly
Ascending aorta
Aortic root dilation
Coarctation of aorta

69. M Mode- Aortic Stenosis
Maximal aortic cusp separation (MACS)
Vertical distance between right CC and non CC during systole
Aortic valve area
MACS Measurement
Predictive value
Normal AVA >2Cm2
Normal MACS >15mm
100%
AVA>1.0
> 12mm
96%
AVA< 0.75
< 8mm
97%
Gray area
8-12 mm
…..
DeMaria A N et al. Circulation.Suppl II. 58:232,1978

70. M Mode- Aortic Stenosis

71. M Mode- Aortic Stenosis
Limitations
Single dimension
Asymmetrical AV involvement
Calcification / thickness
↓ LV systolic function
↓ CO status

72. Approach 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/ assess COA
AR – quantification if more than mild
MR- mechanism & severity
Pulmonary pressure

73. THANK YOU

74. MCQ -1 Which is false about Severe AS? Aortic jet velocity > 4 m/s
Velocity ratio > 0.50
Indexed AVA < 0.6 cm²/m²
Mean gradient > 40 mm Hg
None of the above

75. MCQ-2
By definition Low-flow low-gradient AS includes the following conditions except
Anatomic orifice area < 1.0 Cm2
LV ejection fraction < 40%
Mean pressure gradient < 30–40 mmHg
None

76. MCQ-3 Characteristic feature of calcific aortic stenosis is ………….
Nodular calcific masses on ventricular side of cusps
Calcium deposition at free edges of the cusp
Commissural fusion
None of the above

77. MCQ- 4 False about Maximal aortic cusp separation?
MACS of normal aortic valve is >15 mm
AVA <0.75 corresponds to MACS <8mm
Vertical distance between right CC and non CC during systole
Gray area is 8-12mm
None of the above

78. MCQ 5
All are true about standard dobutamine stress echocardiography for evaluation of AS severity in setting of LV dysfunction except?
A) Uses low dose of dobutamine starting at 2.5 or 5ủg/kg/min
B) Maximum dose of dobutamine used is 10–20 ủg/kg/min
C) The infusion should be stopped when the heart rate begins to rise more than 10–20 bpm over baseline
D) Failure of LVEF to ↑ by 40% is a poor prognostic sign
e) None of the above

79. MCQ 6
In a patient with aortic valve area of 0.6 sq cm(not a low flow low gradient AS) continuous wave Doppler velocity will be:
a) 1-2 m/sec b) 2-3 m/sec c) 3-4 m/sec d) > 4 m/sec

80. MCQ-7 True about doppler assessment of AS is all except ?
With severe obstruction, maximum velocity occurs later in systole
Angle correction is likely to reduce errors in measuring peak transvalvular gradient
Apical and suprasternal windows most frequently yield the highest velocity
None of the above

81. MCQ-8 True a bout Bicuspid valve is?
Fusion of the right and non-coronary cusps occurs in 80% of cases
Fusion of the right and non-coronary cusps is more commonly associated with mitral vale myxomatous disease
Parasternal short axis view in diastole always demonstrate bicuspid anatomy
Calcification usually occurs along the edges of cusp

82. MCQ -9 True about Supravalvular aortic stenosis is all?
Type 2 shows doming in systole
Type 3 hourglass appearance of aorta
Type 1is thin discrete fibrous membrane
Type 3 is localized disease just above aortic valve

83. MCQ- 10 All are true except
accuracy of the Bernoulli equation to quantify AS pressure gradients is well established
The relationship between peak and mean gradient depends on the shape of the velocity curve.
Gradients are calculated from velocity information
Dynamic sub aortic obstruction shows a characteristic early peaking velocity curve
None

84. MCQ -1 Which is false about Severe AS? Aortic jet velocity > 4 m/s
Velocity ratio > 0.50
Indexed AVA < 0.6 cm²/m²
Mean gradient > 40 mm Hg
None of the above

85. MCQ-2
By definition Low-flow low-gradient AS includes the following conditions except
Anatomic orifice area < 1.0 Cm2
LV ejection fraction < 40%
Mean pressure gradient < 30–40 mmHg
None

86. MCQ-3 Characteristic feature of calcific aortic stenosis is ………….
Nodular calcific masses on ventricular side of cusps
Calcium deposition at free edges of the cusp
Commissural fusion is common and early
None of the above

87. MCQ- 4 False about Maximal aortic cusp separation?
MACS of normal aortic valve is >15 mm
AVA <0.75 corresponds to MACS <8mm
Vertical distance between right CC and non CC during systole
Gray area is 8-12mm
None of the above

88. MCQ 5
All are true about standard dobutamine stress echocardiography for evaluation of AS severity in setting of LV dysfunction except?
A) Uses low dose of dobutamine starting at 2.5 or 5ủg/kg/min
B) Maximum dose of dobutamine used is 10–20 ủg/kg/min
C) The infusion should be stopped when the heart rate begins to rise more than 10–20 bpm over baseline
D) Failure of LVEF to ↑ by 40% is a poor prognostic sign
e) None of the above

89. MCQ 6
In a patient with aortic valve area of 0.6 sq cm(not a low flow low gradient AS) continuous wave Doppler velocity will be:
a) 1-2 m/sec b) 2-3 m/sec c) 3-4 m/sec d) > 4 m/sec

90. MCQ-7 True about doppler assessment of AS is all except ?
With severe obstruction, maximum velocity occurs later in systole
Angle correction is likely to reduce errors in measuring peak transvalvular gradient
Apical and suprasternal windows most frequently yield the highest velocity
None of the above

91. MCQ-8 True a bout Bicuspid valve is?
Fusion of the right and non-coronary cusps occurs in 80% of cases
Fusion of the right and non-coronary cusps is more commonly associated with mitral vale myxomatous disease
Parasternal short axis view in diastole always demonstrate bicuspid anatomy
Calcification usually starts along the edges of cusp

92. MCQ -9 True about Supravalvular aortic stenosis is all?
Type 2 shows doming in systole
Type 3 shows hourglass appearance of aorta
Type 1 is thin discrete fibrous membrane
Type 3 is localized disease just above aortic valve

93. MCQ- 10 All are true except
accuracy of the Bernoulli equation to quantify AS pressure gradients is well established
The relationship between peak and mean gradient depends on the shape of the velocity curve.
Gradients are calculated from velocity information
Dynamic sub aortic obstruction shows a characteristic early peaking velocity curve
None