AORTIC STENOSIS DOPPLER ASSESSMENT unit 1

DOPPLER ECHO: AORTIC STENOSIS

ASSESSMENT

Severity of stenosis is determined by 5 steps what are they

1-Peak flow velocity

2 – Mean pressure gradient

3 – Aortic valve area

4 – Dimensionless index

5 – Simplified Continuity Equation

PEAK AORTIC FLOW VELOCITY ASSESSMENT

what does this measure, and how is this measured?

Antegrade systolic

velocity across the AV

• HIGHEST CW Doppler

jet

PEAK AORTIC

FLOW VELOCITY

Optimization how would you want to optimize the doppler signal

what will you do with the gains and wall fillter and the baseline and scale

what about the sweep speed where do you trace and what are the best views

Optimize Doppler signal

1- Decrease gains and increase

wall filter

2 – Adjust Baseline and scale

3 – Increase sweep speed

4- Trace TVI of outer edge of

signal (avoid noise and fine linear

signals)

B e s t V i ew s : A p i c a l 3 o r 5 C h am b e r,

Right Sternal Border, right

c l a v i c ul a r, and Suparsternal Notch

AS PEAK VELOCITY: SEVERITY SCALE

ASSUMES NORMAL CARDIAC

OUTPUT

Aortic sclerosis

mild

moderate

severe

The mean pressure gradient is the difference in what?

Average Gradient across the? during what cardiac cycle

what equation is used at several velocity points and averaged

reported in what units

Difference in pressure between

the left ventricle and aorta in

systole

• Average gradient across the

aortic valve during entire systole

• Simplified Bernoulli equation is

used at several velocity points

and averaged

• Reported in mmHg

AS MEAN GRADIENT SEVERITY SCALE

what are the mild, moderate, severe numbers

Peak velocity and mean pressure gradient A ___ tracing provides what both are what dependent

A TVI tracing provides both mean

gradients and peak

velocity/gradient

Both are flow dependent

(Check prior echos for the best

view and highest velocity)

what are the Possible errors in measuring (3)

Incorrect identification of the flow

signal

• (e.g., mistaking the mitral regurgitation signal

or dynamic obstruction for AS)

• Respiratory motion

• Measurement variation among

sonographers

Continuity Equation AVA, what does it calculate using the continuity equation

•Volume flow proximal to and in

the stenotic orifice is equal

Continuity Equation AVA, independent of what can be used to calculate what

Independent of

flow, can be used

to calculate area

with AI, high or

low output states

Continuity Equation AVA, Measures

effective orifice

area what is this

Effective orifice area

(EOA) is the standard

parameter for the

clinical assessment of

aortic stenosis severity

AVA calculates solving for the

AVA calculates solving for the

narrowest area...aka EOA

AS – continuity equation

Calculation of AVA Continuity equation

Measurements needed what are and what is the formula

LVOT diameter

LVOT velocity VTI (PW)

AV velocity VTI (CW)

Measurement of LVOT Diameter

in what view

measure in what cardiac cycle

what are the caliper placement

what are the normal values

what are the normal values between male and female

PLAX

Measure in early-mid systole

Caliper placement

• Insertion-to-insertion

Normal Values 1.8 – 2.4 cm

• Male 2.0-2.4

• Female 1.8-2.2

Measurement of LVOT TVI

you may lose what as stenosis increase

what is the normal LVOT TVI?

Heart rate takes at time of what measurement for accurate what assessment

•You may lose the valve click as

stenosis increases

•Normal LVOT TVI

• 18 – 22 cm

•Heart rate taken at time of SV

measurements for accurate CO

assessment

measurements of at least how many beats should be averaged for pt in normal sinus rhythm

3 beats

measurements of at least how many beats should be averaged for a pt with an arrhythmia like A-Fib

5 beats

LVOT spectral Doppler

you want to be what with flow?

Identify what velocity

what do you want to do with the doppler gain and compression

and how do you trace to obtain what

Choose the most parallel

to flow (PTF)

Identify modal velocity

Decrease Doppler gains

and lower compression

Trace outer edge of modal

velocity to obtain the TVI

normally the AV demonstrates a what waveform with a what acceleration time. Mild AS left demonstrates a ____ waveform with a what acceleration time. sever AS on the right demonstrates a what waveform with what acceleration time

CONTINUITY EQUATION:

Limitations what are they?

Pitfalls…

1-Requires 3 measurements

2-LVOT diameter squared

3- Irregular rhythms

4-TDS

CONTINUITY EQUATION: (which one is the greatest potential source of error?

Limitations

Pitfalls

1-Requires 3 measurements

why

2-LVOT diameter squared

Calcification may result in what

LVOT is not circular which may cause what

3- Irregular rhythms

why

4-TDS

why

Pitfalls

1-Requires 3 measurements

– More room for error

2-LVOT diameter squared

– Greatest potential source of error

– Calcification may result in a small diameter

– LVOT is not circular which may cause underestimation in SV and AVA

3- Irregular rhythms

– Need to take multiple measurements

4-TDS

– Multiply errors

•Additional assessments recommended for

severity of aortic stenosis

•Simplified Continuity Equation (cm2)

•Indexed AVA (no units)

•Planimetry of aortic valve anatomic area

(cm2)

•Additional assessments recommended for

severity of aortic stenosis, describe each one

•Simplified Continuity Equation (cm2)

• The ratio of LVOT to aortic velocity is similar to the

ratio of VTIs with native aortic valve stenosis

•Indexed AVA (no units)

– Effective AVA expressed as a proportion of the LVOT

area

– Does not consider size of the LVOT

•Planimetry of aortic valve anatomic area

(cm2)

• Anatomic (geometric) CSA of the aortic valve orifice as

measured by 2D or

3D echo

AS

Measurements

/Equations

AS

Measurements

/Equations Dimensionless index

Dimensionless Index This measurement is available when? The dimensionless index expresses what?

This measurement is available when we

aren’t able to see or measure the LVOT

diameter in PLAX

The dimensionless index expresses the size

of effect orifice area and removes body size

Dimensionless Index limitations

Limitations: It removes body

size which varies from person

to person

Dimensionless Index

no stenosis = ratio will be what

as the stenosis gets more sever, what happens to the numbers

No stenosis = ratio will be 1

As the stenosis gets more severe, the numbers

decrease

Planimetry is difficult in

stenosis due to? Planimetry can used during what

Planimetry is difficult in

stenosis due to

calcification around the

valve with TTE

Planimetry can used

during TEE

Limitations to grading Aortic

Stenosis, when We cannot calculate AVA

With dynamic sub-aortic obstruction or a subaortic

membrane, SV calculations are not accurate

what are other Limitations to grading Aortic

Stenosis (think of things that can overstimates mean gradient and alter the peak velocity/mean gradient

Significant Aortic Insufficiency with Aortic Stenosis

Creates high subaortic flow rates

Overestimates mean gradient

Hypertension can alter the peak velocity/mean gradient and

should therefore be recorded for every examination

what is this showing

FIXED DOPPLER

SIGNAL VERSES

DYNAMIC

DOPPLER SIGNAL

What are the limitations to grading stenosis (5)

Abnormally high flow - High flow may be

reversible and should be addressed to see

the true severity of stenosis

• Anemia

• Hyperthyroidism

• Arterio-venous shunts

• Patients on hemodialysis that haven’t

gone through treatment

more limitations with MR, MS, how do these affect and when uncontrolled systemic blood pressure is

Mitral regurgitation may reduce the

cardiac output

Mitral Regurgitation signal may be

mistaken for AS signal

Mitral stenosis can also reduce cardiac

output

When uncontrolled systemic blood

pressure is present, it may reduce flow

and EF due to increase pressure

LOW FLOW LOW

GRADIENT

AORTIC STENOSIS what is showing with the numbers

This is a classic example

of when the numbers

don’t match

Pt’s AVA is less then 1.0

And Peak velocity and

mean PG are moderate

Low Flow Low Gradient Aortic Stenosis

is a subset of pt who have what but do not meet to the classic echocardiographic criteria

can we visually see severe AS but what doesnt match due to what

LFLG severe AS is a subset of patients who

have severe valvular stenosis but do not meet

the classical echocardiographic criteria

• We can visually see severe AS but

numbers don’t match

• Due to insufficient flow across the

aortic valve

Low Flow Low Gradient Aortic Stenosis

whats the #1, #2a, #2b

Low Flow Low Gradient Aortic Stenosis

Velocity and gradients are dependant on?

Flow is determined by?

Flow status is equal to

Look at what

Velocity and gradients are dependant on flow!!!!

Flow is determined by flow status

• Flow status is equal to stroke vlume index

• Look at stroke volume index <35 ml/m2

Following conditions can result in

low-velocity/gradient severe AS

with _____EF including: what are they? (8)

hese conditions causing low flow low gradient AS ?% LV EF

Following conditions can result in

low-velocity/gradient severe AS

with preserved EF including:

Tachycardia

• Bradycardia

• Hypertension

• Small ventricular cavity

• Severe diastolic dysfunction

• Severe mitral or tricuspid valve disease

• Pulmonary hypertension

• Left or right ventricular dysfunction

these conditions causing low flow low gradient AS >50% LV EF

Low Flow Low Gradient AS <50% LV EF what is this telling what and what do we need to determine and what is decreased

Reduced EF <50%

If EF is decreased velocities and gradients are

decreased

If the EF is reduced (<50%), then we need to

determine if the decrease in valve opening (AVA)

is due to true severe AS or LV dysfunction!

Low Flow Low Gradient AS <50% LV EF

Move forward to Dobutamine Stress Echo

The test tells us

Contractile Reverse- contractile response to

Dobutamine

Stroke Volume- Presence of flow reverse (> 20%

SVI from baseline)

More in Stress Echocardiography

what are the Differentials

Left Ventricular Obstructions can be

caused by the following...(3)

Fixed subvalvular obstruction (a

subaortic membrane or a muscular

subaortic stenosis)

• Dynamic subaortic obstruction

(hypertrophic cardiomyopathy)

• Supravalvular stenosis

what is the medical treatment? (7)

Rheumatic Fever Prophylaxis

Diuretics

Ace inhibitors/Nitrates/Beta blockers

High cholesterol drugs

Cardioversion for Afib

Limitations on Activities an exercise in severe AS

Screening of first degree relative

what is the surgical treatment

SAVR (surgical aortic

valve replacement)

TAVR (transcatheter

aortic valve

replacement)

what are some other surgical treatments provides how many months of AS relief?

Aortic Balloon Valvuloplasty

Only provides < 6 months of AS

relief

Surgical

Treatment

Ross procedure: what is it

Pulmonary valve

transplant to aortic

position, reimplantation

of the coronary arteries,

and placement of a

homograft in pulmonary

position