1. Aortic stenosis can present in various forms depending on the location and cause, ranging from valvular to subvalvular and supravalvular forms. Low-flow, low-gradient aortic stenosis presents unique challenges in assessing severity and determining appropriate treatment. 2. Dobutamine stress echocardiography is useful for differentiating true from pseudo severe low-flow, low-gradient aortic stenosis and for assessing flow reserve. New parameters such as projected valve area and valve calcium scoring can also aid in assessment. 3. Paradoxical low-flow, low-gradient severe aortic stenosis with preserved ejection fraction represents a more advanced form with significant left ventricular remodeling, fibrosis and restrictive

1. MOHAMMAD TARIQ ALI

2. Epidemiology -
 1-2 % age 65 yr or older & 12 % age 75 yr or older
 Aortic valve sclerosis without stenosis –irregular
thickening or calcification - 9 % at mean age 54 yr to
42% at mean age 81 yr
 Rate of progression from sclerosis to stenosis – 1.8%/yr

3. Aortic stenosis: Classification based on location
Valvular-
most common type.
Subvalvular.
Supravalvular.

4. Valvular Aortic Stenosis: Etiology

6. Calcific Aortic Stenosis of trileaflet valve

7. Bicuspid Aortic Valve

8. Bicuspid Aortic Valve

11. Rheumatic aortic stenosis

12. Subvalvular aortic stenosis

14. Supravalvular aortic stenosis

15. Congenital aortic valve disease -
 M/C Abnormality –failure of cusp formation
 bicuspid ,Uncuspid , quadricuspid , dome shaped
diaphragm

18. Quantitation of aortic stenosis severity
 Standard evaluation of stenosis severity includes-
(EAE/ASE Recommendations for Clinical Practice 2009).
1. Maximum aortic jet velocity ( Vmax)
2. Mean transaortic pressure gradient
3. Continuity equation valve area ( EOA)

19. Classification of ASseverity
(based on 2014 AHA/ACC Valvular heart diseaseguideline)

21. Peak transvalvular velocity measurement

22. Peak transvalvular velocity

23. Peak transvalvular velocity

25. Mean transvalvular gradient

27. Mean transvalvular gradient

28. Sources of error for pressure
gradient calculations

29. Sources of error for pressure gradient
calculations

30. Aortic valve area Continuity equation

32. Aortic valve area Continuity
equation

34. Advantage of the Continuity Equation over
Peak velocity Pressure gradient

35. Pitfalls of the Continuity Equation

36. Pitfalls of the Continuity Equation

37. Other indicies of severity of AS
 Simplified continuity equation
AVA = LVOT area X LVOT velocity / AS velocity
 Dimentionless index = LVOT VTI / AS VTI
< 25 % of the normal i.e o.75 – 1.0 cm2 - severe AS ( NORMAL 3-4 sq cm )
 Planimetry of Aortic anatomicvalve area – difficult in
severe calcified valve – 3D > 2D , TEE>TTE
 Projected Ao Valve area at normal flow-
AVAPROJ = AVAREST - VC (250 - Qbasal ) @ DSE
 Valvoarterial impedence (Zva) =mmHg/ml/sq m
Zva = Pmean + SBP / SV index

38. Used in special condition -
 LV STROKE WORK LOSS
 RECOVERED PRESSURE GRADIENT
 ENERGY LOSS INDEX
 AORTIC VALVE RESISTANCE

39. 3 variants of severe AS-
1. NORMALFLOW–HIGH GRADIENT SEVERE AS WITH NORMAL EF (
stage c & d1)
2. CLASSIC– LOWFLOW–LOWGRADIENT SEVERE AS WITH REDUCED
EF ( <50%) ( stage d2)
(A) TRUE
(B) PSEUDO
3. PARADOXICALLOWFLOW–LOWGRADIENT SEVERE AS WITH
NORMAL EF(stage d3)

44. Classic LG-LF severe AS with low EF
(STAGE D2 ) -
 EOA < 1.0 cm2
 iEOA < 0.6 cm2 /m2
 Low mean trans valvular gradient < 40 mmHg
 Low EF < 40 %
 Low flow – Cardiac index < 3 L/min/m2
stroke volume index < 35ml /m2
2 types – TRUE & PSEUDO (20-30%)

45.  TRUE severe AS – LG/LF- 1’ Culprit valve ds
LV dysfunction -2’ or concomitant
benefits from AVR
 PSEUDO severe AS – LG/LF – 1’ Myocardial ds
AS severity is overestimated d/t incomplete
opening of Ao valve in relation to LF state
may NOT benefit from AVR

46. LV Flow reserve –
 Percentage increase in stroke volume > 20% during
DSE or catheterization k/a flow reserve & carries
better prognosis & lesser operative mortality than No
flow reserve ( <20%) which has higher prevalence of
multivessel CAD
 Imp predictor of operative risk & survival after AVR

47. DOBUTAMINE STRESS ECHO -
 To differentiate b/w true & pseudo ( ACC/AHA-
ESC/EACTS Class II a (LOE-B )
 To assess LV flow reserve
 pseudo AS- peak stress mean gradient <30 or 40
mmHg , peak stress EOA >1.0 or 1.2 cm2 &/or absolute
incr EOA >0.3 cm2, Vmax < 4 m/sec
 Results – EOA <1 cm2 , Vmax >4 m/sec , any flow-true
EOA <1 cm2 , Vmax < 4 m/sec –persistant
area – gradient mismatch

49. NEWER parameter
 PROJECTED EOA – ambiguous response of DSE d/t
unpredictability of flow augmentation
TOPAS study ( true or pseudosevere AS )
At standard flow rate of 250ml/sec ESP severe AS with
no contractile reserve
 Mutislice CT
>1650 Agatston
Unit

52. NEWER CLASS-
Paradoxical LF-LG Severe AS ( stage D3) -
 Normal EF ( >50%)
 Pronounced LV concentric remodelling
 Small LV cavity size
 Restricted physiology leading to impaired LV filling
 Altered myocardial function
 Low flow with normal EF –Under estimation of AS
 Worse prognosis

53.  Parameters :- EOA < 1.0 cm2 , i EOA <0.6 cm2/m2 ,
restrictive physiology resulting into low CO ( <3
l/min/m2 or indexed SV < 35 ml/m2 ) & lower than
expected tranvalvular gradients (<40mm Hg) despite
the presence of preserved LVEF (>50%) -
LG/LF-AS-pEF - PARADOXICAL AS

54. Pathophysiology & clinical presentation of paradoxical
LG-LF AS -
 Many similarities with HFpEF = older age , female
gender , concomitant syst HTN , restrictive physiology
therefore LV pump function & stroke vol markedly
reduced despite preserved LVEF
 Distinctive feature – (1) more pronounced LV conc
remodelling & myocardial fibrosis- dec LV size ,
compliance & filling
(2)marked reduction of intrinsic LV function NOT
evident by LVEF but by more sensitive parameters like
GLS d/t advanced fibrosis in sub endocardial layers
So paradoxical AS represent advanced stage of both
valvular & ventricular ds despite normal LVEF

56.  Pseudo normalization of BP – d/t LF inspite of redu
systemic arterial compliance &/or incr vascular
resistance
 High Valvulo-Arterial impedence ( Zva )- global LV
hemodynamic load
 Severe ,normal flow , high gradient ,AS with normal
EF vs Paradoxical LG/LF severe AS with normal EF –
AVR ( Best Vs worst outcome ) , medical Vs surgical
 Class II a ( LOE –C) recently inspite of High Operative
mortality & increased chances of pt prosthesis
mismatch d/t small Lv cavity

58. TAKE HOME MASSAGE.....
 LF-LG AS with normal or reduced LVEF – most challenging
situation in valvular heart disease
 DSE greatly aid in risk stratification & clinical decision
 Valve calcium score- MD CT & plasma BNP helpful esp in
NO flow reserve pt with non dx DSE
 GLS has definite role in sub clinical systolic dysfunction &
early treatment in AS
 Paradoxical LG-LF Severe AS with Normal EF – recently
described entity with advanced ds & worse prognosis
 Role of TAVR – in LG/LG AS to be determined in future