9 Aortic stenosis- Causes Most common :-Bicuspid aortic valve with calcificationSenile or Degenerative calcific ASRheumatic ASLess common:-CongenitalType 2 HyperlipoproteinemiaOnchronosis
10 Anatomic evaluationCombination of short and long axis images to identifyNumber of leafletsDescribe leaf mobility, thickness, calcificationCombination 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 cuspsNo commissural fusionFree edges of cusps are not involvedstellate-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 valveFusion 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 valveTwo 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 linesystolic domingdiastolic prolapse of the cuspsIn children, valve may be stenoticwithout 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 asSchaefer 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
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 valveThe membrane usually mobile and may demonstrate doming during systoleType III- Diffuse narrowing
25 Doppler assessment of AS The primary haemodynamic parameters recommended (EAE/ASE Recommendations for Clinical Practice 2008)Peak transvalvular velocityMean transvalvular gradientValve area by continuity equation.
26 Peak transvalvular velocity Continuous-wave Doppler ultrasoundMultiple acoustic windowsApical and suprasternal or right parasternal most frequently yield the highest velocityrarely subcostal or supraclavicular windows may be requiredThree 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 examinationAny deviation from a parallel intercept angle results in velocity underestimationThe 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/sWall filters are set at a high level and gain is decreased to optimize identification of the velocity curve.Grey scale is usedA 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 shapeWith 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 dynamicDynamic 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 systoleGradients are calculated from velocity informationThe relationship between peak and mean gradient depends on the shape of the velocity curve.
32 Mean transvalvular gradient Bernoulli equationsΔP =4v²The maximum gradient is calculated from maximum velocity ΔP max =4v² maxThe 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 ignoredWhen 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 differenceThe accuracy of the Bernoulli equation to quantify AS pressure gradients is well established
36 Pressure recoveryThe 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 recoveryPressure recovery is greatest in stenosis with gradual distal wideningAortic stenosis with its abrupt widening from the small orifice to the larger aorta has an unfavorable geometry for pressure recoveryPR= 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:
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 orificeAVA= CSA LVOT×VTILVOT / VTIAVCalculation of continuity-equation valve area requires three measurementsAS jet velocity by CWDLVOT diameter for calculation of a circular CSALVOT 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 systoleLVOT 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 variabilityAS 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 accurateSample 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 rateAS and normal LV function, the effects of flow rate are minimalThis 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 Cm2LV ejection fraction < 40%Mean pressure gradient < 30–40 mmHgSevere AS and severely reduced LVEF represent 5% of AS patientsVahanian 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 dobutamineHelpful to differentiate two clinical situationsSevere AS causing LV systolic dysfunctionModerate 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/minThe infusion should be stopped as soon asPositive result is obtainedHeart 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 areStress findings of severe stenosisAVA<1cm²Jet velocity>4m/sMean gradient>40mm of HgNishimura RA et al. Circulation 2002;106:Lack of contractile reserve-Failure of LVEF to ↑ by 20% is a poor prognostic signMonin JL et al. Circulation 2003;108:
51 Serial measurementsDuring 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.
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 / VAVThis method is less well accepted because results are more variable than using VTIs in the equation.
54 Velocity ratioAnother 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/VAVIn 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 unreliablePlanimetry may be inaccurate when valve calcification causes shadows or reverberations limiting identification of the orificeDoppler-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;
57 Experimental descriptors of stenosis severity (Level 3 EAE/ASE Recommendations -not recommended for routine clinical use)
58 Valve resistanceRelatively flow-independent measure of stenosis severityDepends on the ratio of mean pressure gradient and mean flow rateResistance = (ΔPmean /Qmean) × 1333There is a close relationship between aortic valve resistance and valve areaThe 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 aortaSWL(%) = (100×ΔPmean)/ ΔPmean+SBPA 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 pointsAn energy loss index #0.52 cm2/m2 was the best predictor of diverse outcomes (positive predictive value of 67%).
63 Effects of concurrent conditions on assessment of severity
64 Effect of concurrent conditions …… Left ventricular systolic dysfunctionLeft ventricular hypertrophySmall 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… Hypertension35–45% of patientsprimarily affect flow and gradients but less AVA measurementsControl of blood pressure is recommendedThe echocardiographic report should always include a blood pressure measurement
66 Effect of concurrent conditions contd… Aortic regurgitationAbout 80% of adults with AS also have aortic regurgitationHigh transaortic volume flow rate, maximum velocity, and mean gradient will be higher than expected for a given valve areaIn this situation, reporting accurate quantitative data for the severity of both stenosis and regurgitation
67 Effect of concurrent conditions contd… Mitral valve diseaseWith severe MR, transaortic flow rate may be low resulting in a low gradient .Valve area calculations remain accurate in this settingA 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 outputRelatively high gradients in the presence of mild or moderate ASThe shape of the CWD spectrum with a very early peak may help to quantify the severity correctlyAscending aortaAortic root dilationCoarctation of aorta
69 M Mode- Aortic Stenosis Maximal aortic cusp separation (MACS)Vertical distance between right CC and non CC during systoleAortic valve areaMACS MeasurementPredictive valueNormal AVA >2Cm2Normal MACS >15mm100%AVA>1.0> 12mm96%AVA< 0.75< 8mm97%Gray area8-12 mm…..DeMaria A N et al. Circulation.Suppl II. 58:232,1978
74 MCQ -1 Which is false about Severe AS? Aortic jet velocity > 4 m/s Velocity ratio > 0.50Indexed AVA < 0.6 cm²/m²Mean gradient > 40 mm HgNone of the above
75 MCQ-2By definition Low-flow low-gradient AS includes the following conditions exceptAnatomic orifice area < 1.0 Cm2LV ejection fraction < 40%Mean pressure gradient < 30–40 mmHgNone
76 MCQ-3 Characteristic feature of calcific aortic stenosis is …………. Nodular calcific masses on ventricular side of cuspsCalcium deposition at free edges of the cuspCommissural fusionNone of the above
77 MCQ- 4 False about Maximal aortic cusp separation? MACS of normal aortic valve is >15 mmAVA <0.75 corresponds to MACS <8mmVertical distance between right CC and non CC during systoleGray area is 8-12mmNone of the above
78 MCQ 5All 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/minB) Maximum dose of dobutamine used is 10–20 ủg/kg/minC) The infusion should be stopped when the heart rate begins to rise more than 10–20 bpm over baselineD) Failure of LVEF to ↑ by 40% is a poor prognostic signe) None of the above
79 MCQ 6In 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 systoleAngle correction is likely to reduce errors in measuring peak transvalvular gradientApical and suprasternal windows most frequently yield the highest velocityNone of the above
81 MCQ-8 True a bout Bicuspid valve is? Fusion of the right and non-coronary cusps occurs in 80% of casesFusion of the right and non-coronary cusps is more commonly associated with mitral vale myxomatous diseaseParasternal short axis view in diastole always demonstrate bicuspid anatomyCalcification usually occurs along the edges of cusp
82 MCQ -9 True about Supravalvular aortic stenosis is all? Type 2 shows doming in systoleType 3 hourglass appearance of aortaType 1is thin discrete fibrous membraneType 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 establishedThe relationship between peak and mean gradient depends on the shape of the velocity curve.Gradients are calculated from velocity informationDynamic sub aortic obstruction shows a characteristic early peaking velocity curveNone
84 MCQ -1 Which is false about Severe AS? Aortic jet velocity > 4 m/s Velocity ratio > 0.50Indexed AVA < 0.6 cm²/m²Mean gradient > 40 mm HgNone of the above
85 MCQ-2By definition Low-flow low-gradient AS includes the following conditions exceptAnatomic orifice area < 1.0 Cm2LV ejection fraction < 40%Mean pressure gradient < 30–40 mmHgNone
86 MCQ-3 Characteristic feature of calcific aortic stenosis is …………. Nodular calcific masses on ventricular side of cuspsCalcium deposition at free edges of the cuspCommissural fusion is common and earlyNone of the above
87 MCQ- 4 False about Maximal aortic cusp separation? MACS of normal aortic valve is >15 mmAVA <0.75 corresponds to MACS <8mmVertical distance between right CC and non CC during systoleGray area is 8-12mmNone of the above
88 MCQ 5All 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/minB) Maximum dose of dobutamine used is 10–20 ủg/kg/minC) The infusion should be stopped when the heart rate begins to rise more than 10–20 bpm over baselineD) Failure of LVEF to ↑ by 40% is a poor prognostic signe) None of the above
89 MCQ 6In 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 systoleAngle correction is likely to reduce errors in measuring peak transvalvular gradientApical and suprasternal windows most frequently yield the highest velocityNone of the above
91 MCQ-8 True a bout Bicuspid valve is? Fusion of the right and non-coronary cusps occurs in 80% of casesFusion of the right and non-coronary cusps is more commonly associated with mitral vale myxomatous diseaseParasternal short axis view in diastole always demonstrate bicuspid anatomyCalcification usually starts along the edges of cusp
92 MCQ -9 True about Supravalvular aortic stenosis is all? Type 2 shows doming in systoleType 3 shows hourglass appearance of aortaType 1 is thin discrete fibrous membraneType 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 establishedThe relationship between peak and mean gradient depends on the shape of the velocity curve.Gradients are calculated from velocity informationDynamic sub aortic obstruction shows a characteristic early peaking velocity curveNone