Myths and Legends in - Scott Memorial...

4/8/2019

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Myths and Legends in

Vascular

Diagnosis

Phillip J Bendick, PhD RVT FSDMS

Vascular Sonography Education

No Disclosures

We no longer do many types of

testing in the VL

Noninvasive Vascular

Testing – circa 1948We still do many types of

testing in the VL,

We still do many types of

testing in the VL,

just as we have

always done them,

We still do many types of

testing in the VL,

just as we have

always done them,

but we no longer

remember why!

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Mythology

Urban Legends

in Vascular Ultrasound

Historic Baggage

VASCULAR ULTRASOUND

Mythology

The ABI is an indicator

of the presence or absence

of peripheral arterial

disease:

True

False

VASCULAR ULTRASOUND

Mythology

The ABI is an indicator

of the presence or absence

of peripheral arterial

disease:

True

False

- Sometimes

- SometimesX

X

VASCULAR ULTRASOUND

Mythology

The ankle systolic pressure

remains normal until

disease severity reaches

hemodynamic significance

ABI = 1.02

VASCULAR ULTRASOUND

Mythology

A 50% diameter reduction

is hemodynamically

significant:

True

FalseX

VASCULAR ULTRASOUND

Mythology

Hemodynamically

significant disease:

Renal Artery 60%

Celiac Artery 60-70%

SMA 60-70%

SFA / Pop 60-70%

Iliac Artery 70-75%

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VASCULAR ULTRASOUND

Mythology

PSV Velocity Ratio:

50% DR 2

Hemodynamically

Significant 3

75% DR 4

VASCULAR ULTRASOUND

Mythology

An abnormal ABI is an

indicator of the presence

of hemodynamically

significant peripheral

arterial disease:

True

False

X

VASCULAR ULTRASOUND

Mythology

The ABI is not diagnostic

when there is arterial

wall calcification

VASCULAR ULTRASOUND

Mythology

Arterial wall calcification

causes the ABI to be

> 1.30:

True

False

VASCULAR ULTRASOUND

Mythology

Arterial wall calcification

causes the ABI to be

> 1.30:

True

False

- Sometimes

- SometimesX

X

VASCULAR ULTRASOUND

Mythology

ABI:

Right 1.25

Left 0.93

Which leg has disease?

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VASCULAR ULTRASOUND

Mythology

VASCULAR ULTRASOUND

Mythology

In patients with possible

arterial wall calcification

(DM, CRF) –

An ABI >1.30 indicates

calcification;

VASCULAR ULTRASOUND

Mythology



(DM, CRF) –

An ABI >1.30 indicates

calcification; disease

presence and/or severity

unknown

VASCULAR ULTRASOUND

Mythology



(DM, CRF) –

An ABI < 0.90 indicates

significant obstructive

disease;

VASCULAR ULTRASOUND

Mythology



(DM, CRF) –

An ABI < 0.90 indicates

significant obstructive

disease; disease severity

unknown

VASCULAR ULTRASOUND

Mythology



(DM, CRF) –

A normal ABI is not

helpful;

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VASCULAR ULTRASOUND

Mythology



(DM, CRF) –

A normal ABI is not

helpful; disease presence

and/or severity unknown

VASCULAR ULTRASOUND

Historic Baggage & Urban Legends

Why we do

some of the

things we do -

VASCULAR ULTRASOUND


Why we do

some of the

things we do –

and why they

may no longer

be necessary !!

VASCULAR ULTRASOUND


SV size

Parallel to walls

60 degrees

Valsalva

Augmentation

Segmental pressures

Flow in calf veins

Triphasic, biphasic,

monophasic

Temporal tap

Post-exercise ABI

Systolic pressure over a graft

Brachial pressure after mastectomy

Convert DVT to PE by technique

Scattering from RBC too weak

to see

No Doppler signal at 90 degrees

A few possible topics:

VASCULAR ULTRASOUND

Historic Baggage

Use the smallest

sample volume

size possible

VASCULAR ULTRASOUND

Historic Baggage

Use the smallest sample

volume size possible -

1975: Spectral broadening

minimized with a small

sample volume

21st Century: Spectral broadening

is an inherent feature

of linear array probes

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VASCULAR ULTRASOUND

Historic Baggage

Set the sample

volume size to -

Optimize Doppler signal

quality

Make the examination as

easy as possible

VASCULAR ULTRASOUND

Historic Baggage

Angle correct

parallel to the

walls

VASCULAR ULTRASOUND

Historic Baggage

Angle correct parallel

to the walls -

1980: Poor image quality;

flow direction unknown

21st Century: Great image quality;

flow direction unknown

VASCULAR ULTRASOUND

Historic Baggage


to the walls -

Great image quality; flow direction unknown

VASCULAR ULTRASOUND

Historic Baggage


to the walls –

It still works !!

VASCULAR ULTRASOUND

Historic Baggage

Always do spectral

Doppler at 60o

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VASCULAR ULTRASOUND

Historic Baggage

Always do spectral Doppler at 60o

1980: FFT only; no

velocity information

95% of ICA origins

could be done at 60o

VASCULAR ULTRASOUND

Historic Baggage


1980: FFT only; no

velocity information

21st Century: Onboard

computing; velocity

calculated at any angle

VASCULAR ULTRASOUND

Historic Baggage


VASCULAR ULTRASOUND

Historic Baggage


21st Century: Velocity can

be calculated for any

Doppler angle

TrueX

VASCULAR ULTRASOUND

Historic Baggage


Errors increase exponentially

for angles > 60o

Do not exceed 60o for

velocity measurements

VASCULAR ULTRASOUND

Historic Baggage


However, errors may occur

for any angle 0o

For reproducible results

always use as close to the

same angle as possible

≠

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VASCULAR ULTRASOUND

Historic Baggage


For reproducible results always

use as close to the same

angle as possible -

60o is readily achieved in

most peripheral vessels

VASCULAR ULTRASOUND

Historic Baggage

Use the valsalva

maneuver for

venous testing

VASCULAR ULTRASOUND

Historic Baggage

Use the valsalva maneuver for

venous testing

1975: “Blind” CW Doppler;

non-directional,

no imaging capability

21st Century: High resolution

imaging groin to ankle

VASCULAR ULTRASOUND

Historic Baggage

High resolution imaging groin to ankle

VASCULAR ULTRASOUND

Historic Baggage


venous testing

CFV DVT

Resting

CFV DVT

Valsalva

VASCULAR ULTRASOUND

Historic Baggage


venous testing

CFV DVT

Post-Valsalva

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VASCULAR ULTRASOUND

Historic Baggage


venous testing: DVT

Difficult to explain

Effort not reproducible

Potential to embolize

VASCULAR ULTRASOUND

Historic Baggage


venous testing: CVI

Difficult to explain

Effort not reproducible

Use breath hold with

manual abdominal pressure

VASCULAR ULTRASOUND

Historic Baggage

Use augmentation

maneuvers for

venous testing

VASCULAR ULTRASOUND

Historic Baggage

Use augmentation maneuvers for

venous testing

1975: “Blind” CW Doppler;


21st Century: High resolution

imaging groin to ankle

VASCULAR ULTRASOUND

Historic Baggage

Augmentation maneuvers:

Venous testing for DVT

Provide no additional

diagnostic information

VASCULAR ULTRASOUND

Historic Baggage




diagnostic information -

“Augmentation … rarely

provides additional

information.”

Lockhart et al AJR 2005

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VASCULAR ULTRASOUND

Historic Baggage





Are not required by IAC –

Vascular Testing

Are a complete waste of time

VASCULAR ULTRASOUND

Historic Baggage

Venous testing for DVT: IAC-VTSpectral Doppler waveforms from

the CFV and Popliteal Vein

VASCULAR ULTRASOUND

Historic Baggage


Venous testing for CVI

Are essential to provide


Are required by IAC-VT

Take a lot of time

VASCULAR ULTRASOUND

Historic Baggage

Doppler Waveforms –

Triphasic

Biphasic

Monophasic

VASCULAR ULTRASOUND

Historic Baggage


Triphasic

Biphasic

Monophasic

VASCULAR ULTRASOUND

Historic Baggage


1960s: “Blind” CW Doppler;

non-directional,


Analog waveforms

categorized LE PAD

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VASCULAR ULTRASOUND

Historic Baggage

Doppler Waveforms – LEA

Triphasic

Biphasic

Monophasic

VASCULAR ULTRASOUND

Historic Baggage

VASCULAR ULTRASOUND

Historic Baggage


21st Century: Duplex ultrasound

with spectral Doppler

used throughout body

VASCULAR ULTRASOUND

Historic Baggage


21st Century: Use –

Normal or Abnormal

VASCULAR ULTRASOUND

Historic Baggage


21st Century: Abnormal

Proximal obstruction

VASCULAR ULTRASOUND

Historic Baggage


21st Century: Abnormal

Distal obstruction

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VASCULAR ULTRASOUND

Urban Legends

Post-exercise ABI

VASCULAR ULTRASOUND

Urban Legends

Post-exercise ABI

• 2 mph

• 10% grade

• 5 minutes max

Typical Protocol

VASCULAR ULTRASOUND

Urban Legends

Post-exercise ABITotal Walking Time

VASCULAR ULTRASOUND

Urban Legends

Post-exercise ABI

Normal exercise response:

Initial ankle pressure drop

< 25% of baseline pressure

Time to return to baseline

pressure is less than 3 minutes

VASCULAR ULTRASOUND

Urban Legends

Post-exercise ABI

Normal exercise response:

Initial ankle pressure drop

< 25% of baseline pressure

Time to return to baseline

pressure is less than 3 minutes ABI

VASCULAR ULTRASOUND

Urban Legends

Post-exercise ABI

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VASCULAR ULTRASOUND

Urban Legends

Post-exercise ABI “… it is unnecessary and

misleading to record the

postexercise ankle/arm

ratio, which is done

by many laboratories.”

Strandness DE Jr.

Duplex Scanning in Vascular Disorders

VASCULAR ULTRASOUND

Urban Legends






Strandness DE Jr.


VASCULAR ULTRASOUND

Urban Legends






Strandness DE Jr.


VASCULAR ULTRASOUND

Urban Legends

Post-exercise ABI

“It is important to

record only the fall

and recovery time of

the ankle systolic pressure.”

Strandness DE Jr.


Segmental pressures are

essential to the lower

extremity arterial examination -

VASCULAR ULTRASOUND

Historic Baggage

Segmental pressures are

essential to the lower

extremity arterial examination -

or do they represent “historic

baggage” which we still

carry around with us?

VASCULAR ULTRASOUND

Historic Baggage

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When are segmental pressures

unnecessary ?

VASCULAR ULTRASOUND

Historic Baggage


unnecessary ?

~ 15% of LEA examinations

are not related to obstruction

(e.g. aneurysmal disease,

pseudoaneurysm)

VASCULAR ULTRASOUND

Historic Baggage


unnecessary ?

The clinical question is the

presence or absence of disease

VASCULAR ULTRASOUND

Historic Baggage

The ABI is sufficient


unnecessary ?

Normal waveforms and ABIs

plus exercise if history

consistent with true

claudication

VASCULAR ULTRASOUND

Historic Baggage


unnecessary ?

Calcified vessels (ABI artifact)

Hx of DM

VASCULAR ULTRASOUND

Historic Baggage


unnecessary ?

Unable to obtain because of –

Too much leg pain

Severe hypertension

Wounds / Dressings

Disease too severe

Acute DVT

VASCULAR ULTRASOUND

Historic Baggage

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unnecessary ?

Duplex ultrasound done per

protocol –

Prior BPG / Intervention

Aneurysmal disease

Follow-up known disease

A-I inflow disease

Pre-op for severe disease

VASCULAR ULTRASOUND

Historic Baggage


unnecessary ?

250 consecutive LEA studies

for obstructive disease -

VASCULAR ULTRASOUND

Historic Baggage


unnecessary ?


for obstructive disease –

Normal, ABI only 89

Normal with exercise 6

VASCULAR ULTRASOUND

Historic Baggage


unnecessary ?



Calcified vessels 55

DM 19

VASCULAR ULTRASOUND

Historic Baggage


unnecessary ?



Unable to obtain 18

VASCULAR ULTRASOUND

Historic Baggage


unnecessary ?



Duplex ultrasound per

protocol 42

VASCULAR ULTRASOUND

Historic Baggage

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unnecessary ?



Segmental pressures 21 (69)

VASCULAR ULTRASOUND

Historic Baggage


unnecessary ?



Segmental pressures 21 (69)

Additional information 1 ?

VASCULAR ULTRASOUND

Historic Baggage


unnecessary ?

Segmental pressures may be needed

for complete diagnostic information in

only ~ 10% of all lower extremity arterial

examinations

VASCULAR ULTRASOUND

Historic Baggage


unnecessary ?

With duplex ultrasonography readily

available –

Segmental pressures add additional

diagnostic information in < 1% of

lower extremity arterial examinations

VASCULAR ULTRASOUND

Historic Baggage

Stop beating

on yourself –

and your

patients

VASCULAR ULTRASOUND

Historic Baggage

VASCULAR ULTRASOUND

Cast off the old

mythology

Get rid of unnecessary

historic baggage

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VASCULAR ULTRASOUND

Remember:

“Why?”

is still

a good

question !

VASCULAR ULTRASOUND

Thank you

for your attention !!

VASCULAR ULTRASOUND VASCULAR ULTRASOUND


Why we do

some of the

things we do –

and why they

may no longer

be necessary !!

The story of the ham -

VASCULAR ULTRASOUND


Why we do

some of the

things we do –

and why they

may no longer

be necessary !!

The story of the ham -

VASCULAR ULTRASOUND

Urban Legends

The Temporal Tap

1970s: Rapid obstruction –

release of the superficial

temporal artery will

show up in the ECA

Doppler signal

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VASCULAR ULTRASOUND

Urban Legends

The Temporal Tap

VASCULAR ULTRASOUND

Urban Legends

The Temporal Tap

ECA 81%

Kliewer et al Radiology 1996

VASCULAR ULTRASOUND

Urban Legends

The Temporal Tap

ECA 81%

CCA 54%

ICA 33%


CCA

ICA

VASCULAR ULTRASOUND

Urban Legends

The Temporal Tap

VASCULAR ULTRASOUND

Urban Legends

The Temporal Tap

ECA 81%

CCA 54%

ICA 33%


*

* ICA > ECA oscillation

in 26% of cases

Myths and Legends in - Scott Memorial...

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