Vascular Ultrasound Imaging & Doppler Upper Extremity Arteries - SD

Introduction

Hello, my name is Anne Marie Kapinsky
and I'm the president of North Country Vascular Diagnostics
and also a clinical associate professor
of radiology at Albany Medical College in Albany, New York.
I'm going to be speaking today about upper extremity
arterial ultrasound.

Determining the Type of Test

To begin our discussion today on upper extremity arteries,
it's first important to understand what kind
of test you should do,
and the type of test you do is really determined
by the question you want answered.
When we come to arterial testing,
the first question should be,
is there arterial disease present?
It's a yes or no answer to this question,
and physiologic testing will tell us the easiest
and the quickest of whether or not there is disease or not.

Role of Ultrasound in Defining Disease

Once we find out a patient has vascular disease,
then we can use ultrasound
to actually better define the disease,
the location and severity.
And that's where ultrasound really comes into play.
Peripheral arterial ultrasound we know
can exactly identify what piece
of the anatomy we're looking at.
It can tell us a particular point
where there may be something abnormal.
Having that information,
we can help the clinicians then direct additional
intervention for their patient, whether that's
angioplasty and stent or surgery.
But this can be direct information from the ultrasound
that they can utilize for therapy.
We know we can follow disease progression.
We do that all the time with carotid vessels.
And one of the best things about ultrasound is
that we can differentiate stenosis from occlusion.
We can't do that on the indirect tests.
We know that we can get a very high grade stenosis,
or have a vessel completely occluded
and get similar results,
but we can see that difference on ultrasound.
And ultrasound is great
because we can get that anatomy that I discussed,
but we can get the physiology, we can look at velocity,
waveforms and shapes,
and we know what is going on both at that point
and what is going on in the tissue bed being
supplied by that vessel.

Overview of Upper Extremity Arterial Disease

In terms of upper extremity arterial disease,
it's certainly not all that common.
In fact, it only accounts for about 5%
of all symptomatic extremity disease.
It's pretty uncommon for us.
Atherosclerosis is a player,
but it's relatively rare in that most
of the upper extremity arterial disease we see
actually can be caused by a variety of other diseases.
And they're listed here.
Some of them include, as I said, atherosclerosis,
but various types of arteritis
or embolic disease, traumatic disease and thoracic outlet.

Large Vessel Disease

These are problems in the large upper extremity arteries
and large arterial diseases
and it only accounts for five to 10% of the patients.
And this figure over here we see a vessel.
This actually happens to be a common carotid artery
and we can see this diffuse buildup in the wall here
and here, and it's very typical of a patient with arteritis.
We'll come back to that in a second.

Small Vessel Disease

Small vessel disease is really the bulk of
what we see in the upper extremity,
and that's almost 95% of the patients.
The testing we do there
actually can vary depending upon what's going on.
Certainly we'll see some patients
who may have vaso spastic diseases,
and they can be the result of true ray's disease
or uds phenomenon.
We also see patients with connective tissue disorders such
as scleroderma or lupus or rheumatoid arthritis.
Other patients may have, coagulable states.
They may also present with burger's disease
or various other types of problems, including frostbite
or, some sort of neoplasm
or vibrational injury,
which is actually quite common in patients who,
are laborers and use, pneumatic tools to do their job.
They can get diseases within the small vessels
of their upper extremities.

Raynaud's Phenomenon

Now a minute or two here about renos phenomenon,
many patients have this multicolored change that,
their hands, their fingers go through.
Sometimes we don't know why.
That's only a small percentage.
Maybe five to 10% have primary rays disease.
We really have no clue what's going on.
Most patients present with reno's phenomenon,
which is secondary to a number of underlying causes such
as connective tissue disease, thoracic outlet, et cetera.
And the patients go through this classic
colorful pattern of changes.
First, the digits are white, they blanch,
the artery will vasospasm and shut,
and there's no perfusion here.
So the fingers blanch.
Secondly, what happens is the blood remaining in the tissue
becomes deoxygenated
and the tissues become cyanotic or blue.
Lastly, once the stimulus is removed,
the artery stops vasospasm blood flow is returned.
There is a reactive hyperemia here,
and we see this bright red change.
So we go from white to blue to red,
and we get this classic pattern we see in
patients with ray nodes.

Indications for Upper Extremity Ultrasound

Now, in terms of the upper extremity assessment,
why do we ever wind up doing ultrasound
on some of these patients?
Probably one of the big indications would be to look
for a subclavian artery stenosis.
Again, large vessel disease is not common, but it can occur.
Most patients with subclavian artery stenosis
remain asymptomatic.
They don't even know they have it.
It's picked up incidentally
by differences in brachial blood pressures.
Also the few patients that can develop symptoms due
to subclavian artery stenosis are those who use their arms
for their living, such
as a hairdresser or something like that.
They're constantly moving their arms
and they may develop some symptoms as a result.
Also, in patients who've had a cabbage in which they've used
the left internal mammary artery, as a conduit,
if there's a left subclavian artery stenosis, they,
this can spell trouble for those patients as well
and they can actually get angina as a result.
Probably more commonly we're seeing upper extremity
evaluations done
for patients undergoing radial artery harvest for a cabbage
or in a pre-op evaluation prior to the creation
of a dialysis fistula.
Certainly we can also identify hemodialysis axis grafts
and fistulas looking for a stenosis and such.
But that topic is best reserved
for another lecture.
We do see patients though with dialysis access sites
who can develop arterial steels.
And lastly, we can also see patients
for thoracic outlet syndrome.
Although in those patients we may not be doing an ultrasound
as their arterial assessment.

Scanning Technique and Anatomy

This sketch here just shows the normal upper extremity
anatomy and once we get out onto the arm,
it's a pretty easy scan of the brachial and the radial
and the ulnar vessels.
Where the challenge comes is right here at the base
of the neck because of the sternum
and the clavicle hiding portions of the brachiocephalic
and subclavian vessels.
It may be a challenge to get
through all these vessels if you have the availability
of a curved linear array, that transducer will help,
intonate these vessels near the clavicle.
We're usually going to use a mid-range transducer for some
of the subclavian evaluation.
If we're looking on the forearm at the radial
and ulnar arteries, we're probably going
to use a high frequency transducer,
in order to see those smaller, more superficial vessels more clearly.
We're going to look for the same things like a stenosis
calcification, wall thickening.
We're going to record the peak systolic velocity as well
as vessel diameter.
And in some instances we may be asked
to measure volume flow, which I'll explain in a few minutes.

Normal and Abnormal Arterial Appearance

Now, an artery is an artery
and a normal artery should look nice
and thin walled, be smooth
and have an appreciable intimal medial boundary
that we can see as we get various levels of disease.
We'll see plaque and calcification so forth.
Here is a nice normal artery companion vein underneath
and we can see nice thin, smooth walls, no irregularities.
We see a small collateral side branch up here as opposed
to these vessels which have significant disease.
Here's a radial artery down in the forearm
with this intermittent calcification noted here.
Sometimes it's very hard to tell whether
or not this is somebody that's borderline
that perhaps this could be used.
Obviously, if we see extensive calcification,
that vessel is not suitable for use as a conduit.
But this little intermittent, calcification,
if you can compress that artery closed with the weight
of the ultrasound transducer and pushing down
and we can compress that closed,
we probably still have enough compliance
that the vessel would be suitable if they
had no other conduit.
And over here, here's another example of a diseased artery.
This is, a copy of a copy, so it's a little bit grainy,
but we can see this person has an arteritis
and there's this uniform thickening to the vessel wall.
It doesn't look like plaque at all
and that's very common in patients with an arteritis.

Spectral Doppler Analysis

Spectral analysis rules are going to be the same
as we do anywhere else.
We're going to use 60 degrees or less.
We're going to record the velocities if we suspect disease.
We're going to use velocity ratio
and look for post stenotic turbulence.
And if we do measure volume flow for some reason,
we're going to make sure we open up our sample gate.

Normal Waveforms

In general, any peripheral artery leg
or arm is going to have a multiphasic high resistance pattern.
We're going to see this sharp upstroke in systole
and narrow peak coming back
with a small reflected wave here.
This reverse flow component is caused
by the blood traveling down the vascular tree
and hitting the high resistance arterials at the end
of the circuit and being reflected back.
Then usually we'll see a third component, this little bit
of antegrade flow in diastole.
That little bit of antegrade flow is the result of the fact
that in systole, the vessels expand, they're nice
and compliant and elastic,
and that expansion actually holds a volume
of blood out near the wall.
And we can see that expansion when we watch the pulsatility,
occur in vessels in diastole.
When the pressure decreases the,
the walls contract back again due to that elastic recoil.
A volume of blood
that's held out there gets propelled downstream
and that gives us that third antegrade component.
Now some vessels,
normally some patients have normal age related changes
or they've lost some compliance and lost some elasticity.
So we may not see this third component
and we may just see two components to the waveform,
but that's perfectly okay.
So here we have a normal high resistance distal radial
artery, but down here we have
a little bit different pattern.
Although we have a nice sharp up stroke
and narrow peak, we see extensive
diastolic flow through here.
And this diastolic flow is indicating to us that this was
a high resistance bed and now it's become a low resistance bed due
to all this blood flow, through diastole.
This can happen in a patient who's warm
as the hand is very temperature sensitive
and causes vasodilatation.
This can also happen if a person was exercising their arm
or hand for any reason.
And this is the type of pattern you would see.

Abnormal Waveforms

We don't want to see these types of patterns here.
There's a lot of diastolic flow,
but look at the waveform itself.
The waveform is prolonged and rounded.
This is a tardus parvus like waveform. It's delayed.
This tells me right off the bat that this blood has moved
through a stenosis somewhere.
It's lost some energy. It's dampened out.
You don't even need to know
or appreciate what the velocities are here.
If you just look at the waveform, you should be able
to say that's abnormal.
Same thing for down here.
Don't even look at the absolute peak velocity.
It's not important. The important part is here we have just
one component, just this up
and down here, this monophasic pattern in systole,
no reverse flow, no reflected wave, no antegrade flow
through end of diastole.
So we know that this is an abnormal signal
and this type of pattern is observed proximal
to a high grade stenosis.

Diagnostic Criteria

Alright, in terms of diagnostic criteria,
there are no separate criteria
for the upper extremity vessels.
We're going to use the criteria that we also apply
to the lower extremity.
In general, these velocities are probably a little high
for the upper extremity arteries,
but what we're going to use really is the velocity ratio.
When we see a ratio that's two to one,
we know we're dealing with about a 50% stenosis.
When the ratio gets up to about four to one,
we know we're dealing with about a 75% stenosis.
And you're not supposed to say all or none or always
or never, but this is a time
where this almost always holds true.
So two to one ratio, 50%, four
to one ratio greater than 75%.
And again, we'll see this focal change.
Now this slide, borrowed from SUNY upstate in Syracuse just shows again some
nice anatomy here where we start.
Of course the sternum's going to be kind of covering most
of these vessels, so we're not really going
to see the origin of the subclavian
or the full extent of the brachiocephalic or a nominate,
but we're going to have to just come in where we can.
And we see here, here's the innominate
or brachiocephalic artery.
We can see it coming up
and horizontally coming off this vessel will be the
subclavian artery as shown here.
And coming up more pointing up towards
the head, towards the neck.
It's going to be the common carotid artery
in terms of waveforms.

Waveforms of Proximal Vessels

The innominate vessel, normally will have a fair amount
of diastolic flow as shown here.
That diastolic flow is a result of the fact
that the innominate gives rise to the common carotid,
which gives rise to the internal carotid.
So that is where
that diastolic flow is going up the ICA to the brain.
Now the subclavian, again, feeding the hand,
feeding the arm is going
to be more multiphasic high resistance pattern.
When we see a subclavian though that looks like this,
we can appreciate that there is something going on.
Again, we don't even have to look at the numbers.
You can see there, there's extensive spectral broadening.
The waveform is kind of rounded.
This is a stenotic signal
and in this case we've got velocities here in this,
example, peaking out of over 350 centimeters per second downstream.
Again, we would expect turbulence and rounding
and blunting of the waveform as shown below.

Pulse Volume Recordings and Pressure Studies

This is an upper extremity pulse volume recording
and segmental pressure study.
And we can see here tracings from the upper arm,
from the forearm and from the wrist.
And on the right here, these are textbook normal.
We see a small reflected wave.
We see a nice sharp upstroke on the left.
We see this prolonged upstroke, this broadening here
and this widening of the pulse.
We lose that reflected wave.
We don't see much of a change from the upper arm
to the forearm to the wrist.
So what we can safely assume is
that the problem is at the beginning
that there is probably something up here in the subclavian
leading down so that when we take a look in the upper arm,
we already see a change
and that change is probably the result of a subclavian.
Artery stenosis. We can see that in these waveforms.
And we can also see here in the doppler,
pressure measurements in that we have greater than a 40
millimeter mercury difference left to right.
We don't really see, much of a change as we go down,
to the wrist level in terms
of a drop off in those pressures.
So this is a classic pattern that we would expect
to see in a patient with a left subclavian artery, stenosis
continuing on out the arm.

Evaluation of Distal Vessels

What we want to do is see these nice paired veins
with a companion artery
and here's the axillary artery and vein.
We see the doppler placed in the axillary artery here
with a peak velocity of around 100.
We are seeing this multiphasic high resistance pattern,
which is exactly normal.
Further down the arm,
we're going to follow the brachial artery.
The brachial is very important
because, some general surgeons like
to create dialysis fistulas using that brachial artery
as an inflow source.
They'll do the basilic vein transposition
and transpose that basilic vein
and anastomosis to the brachial artery.
And that's why we really need to pay good attention to this.
Measuring the diameter and looking at the velocities.
And again, a very textbook normal brachial artery
waveform that we see here.
Continuing on down
that we'll look at both the radial and the ulnar.
Remember in the forearm we've got one artery
with two small veins on either side, the companion veins
to the radial artery.
This is the radial artery.
These vessels up here that are all by themselves
with nobody next to them.
Those are veins.
And if you see these
and they happen to be thrombosed,
it's not a thrombosed radial artery look around,
the radial artery has to have their veins next door.
And that's going to be your landmark
to distinguish this from this.
And don't get confused again,
the radial artery multiphasic a high resistance pattern
except if your patient is hot or they're vasodilated.
Some drugs can cause this as well.
And we can see this vasodilatation,
however, it is still normal.

Preoperative Evaluation for Coronary Artery Bypass

One of the other areas that we get asked
to look at the upper extremities
for are in patients undergoing coronary artery bypass.
We need to evaluate the radial
and the ulnar arteries to make sure, they're adequate.
Look for calcification, confirm
that the vessel's still compliant,
and we're going to record the diameter
and the velocities within these vessels.
In terms of measuring the diameter,
it's probably best if we use a transverse view
and, we can best appreciate
that we're not oblique to this artery.
You can do it longitudinally,
but we have to be very careful in this example.
The vessel, measured longitudinally was 2.6 millimeters versus
2.8 millimeters transverse.
That's all right. But if somebody is borderline,
we want to be careful and make sure we
don't disadvantage them.
This data was, early data.
We compiled, back in Albany looking at males and females
and diameters and velocities.
Females did indeed have slightly smaller radial
arteries than males.
And as such, having the smaller tube to put that blood flow
through, we had slightly higher velocities.
Why we look at the radial artery
and the ulnar artery is we want some sort of assessment
of really what's going on to the perfusion to the hand,
because we want to make sure that if we take
that radial artery out, number one,
it's a good conduit to use.
But number two, that the digital perfusion will be maintained
because not everyone has a complete palmar arch.
One way to test for that is with physiologic testing.
Again, here's an example where it's probably better
to use physiologic testing than arterial ultrasound imaging.
Here we have, PVR waveforms of the digits
of the right hand,
and then we've manually compressed the radial artery
and we repeat these
and we can see the, these are textbook normal.
We've got, again, a sharp upstroke, a narrow peak,
the reflected wave here.
No change all the way down,
but when we compress that radial artery,
we pretty much flatten these waveforms out.
So we can safely say that this kind of patient,
we don't want to harvest the radial artery to use
for coronary bypass
because we probably will get some digital ischemia.
And this is a result of the fact
that the person is radial dominant
and likely has either, a small or, ulnar artery that's not perfusing much
or certainly not perfusing, adequately into the hand.

Evaluation for Dialysis Access

The other reason why we're going
to evaluate these native vessels, as I said
before, would be in patients prior to the creation
of a hemodialysis access fistula or graft.
In general, we're still going to do the radial
and the ulnar arteries, but we're going
to add a brachial artery evaluation.
We certainly also will look at the veins
and this might be the one place
where a surgeon might want to know what the volume flow is
through, those vessels in order
to determine perhaps potential in terms of, runoff bed.
This diagram shows a number of, variations with the creation of a fistula, of course,
the old and most common here, radiocephalic, fistula down here at the wrist,
a basilic vein transposition here, loop grafts and,
various other configurations.
So you can see why they need to know
what the arteries look like in order to, make the best conduit.

Volume Flow Measurement

Measuring volume flow.
Every machine pretty much nowadays can do this.
The operator's going to dial in the vessel diameter.
The machine calculates the radius obviously is half the
diameter and then measures the area of that vessel as
the radius squared times pi.
Then what we also do is dial in, a series of some calipers to,
obtain the mean velocity over a series of cardiac cycles.
And you can see this aqualine drawn through here,
which is actually the mean velocity occurring here.
So we've measured the area of the tube,
we know the mean velocity of the tube.
Multiply those two together
and we can get volume flow through that particular artery.

Complications in Fistulas and Grafts

Well, after we've created a fistula,
we can run into problems in the upper extremity.
Certainly one of the most common is a pseudoaneurysm.
It's going to have the classic appearance
as any pseudoaneurysm with this swirling
of color in two directions.
We may not only have a pseudoaneurysm,
but we may get an arteriovenous fistula,
which is shown here between the brachial artery
and brachial vein following a brachial artery
catheterization for coronary cath.
And we can see also in addition to the fistula, this small,
pseudoaneurysm present as well, if we're being asked
to evaluate a hemodialysis access graft and we start out
and we are looking at the brachial artery, see this kind
of pattern, which is high resistance, we know
that there's a problem already.
This should be our flag to say,
this is actually a good brachial artery doppler signal,
but it's not a good signal in a patient
with a fistula.
In a patient with a fistula.
We need a low resistance signal
because that fistula is created
and we should have lots of diastolic flow.
So if you start out here, we are probably dealing
with somebody with a thrombosed fistula.
The other complication that can occur in fistulas
is arterial steal.
And it's really important in these patients,
to know your orientation
and be careful of how you're positioned
and, make sure that you have everything set correctly.
'Cause we see here in this example,
heads up here, hands down here.
So flow should be going towards the hand
or away from the transducer, away from that doppler beam.
So it should be a negative shift.
But if we look over here, this is actually a positive shift,
even though it sort of looks like an arterial waveform,
although slightly strange one, it's a positive shift.
So it's coming in this direction from the hand back
to the fistula, and that's a patient that needs that kind
of, problem addressed.

Other Conditions

Just a couple more slides now.
This is a patient with Buerger's disease,
and almost all of them are associated
with heavy cigarette smoking.
They get this digital ischemia and cyanosis.
Here we have a radiograph showing an angiogram, I should say,
showing, thoracic outlet compression
with a normal subclavian artery.
At rest, the arm is moved into a certain position
and we get compression of the subclavian artery.
That is very easy to document, again, not necessarily
with ultrasound, but with physiologic studies as shown here
where we can see that, we can get digital
PPGs in certain positions.
But when we move the patient into a symptomatic pose,
we can see the PPG decrease
and we know we've got subclavian artery compression.
Raynaud's testing, again, another type of digital problem.
We see the PVR cuff here,
PPG sensor here we can measure pressure.
We can get PPG waveforms.
This peaked pulse is extremely characteristic
of patients with Raynaud's.
If you examine any
of the publications coming out of Portland, Dr.
Mineta's group and formerly Dr. Porter, when he was alive,
they published extensively about Raynaud's
and this peaked pulse appearance as compared to this type
of patient, which is not really as significantly,
displaying a peak pulse.
This is more obstructive lesion that comes into play.
And this last case, an example, is a patient who
used the palm of their hand to repeatedly,
hit something together.
What they were doing, we don't know,
but again, over time in that repeated trauma to the palm
of their hand, they actually created
an ulnar artery aneurysm.
And we can see the aneurysm here
and the thrombus within the aneurysm reduced flow lumen on
color, even though the doppler spectrum is normal.
This was, a patient with a potentially serious issue here.

Conclusion

So to conclude, when evaluating the upper extremity
arteries, we're going to use the same criteria that we do
for lower extremity arterial ultrasound.
We can detect atherosclerosis
and we can detect other things such as aneurysm
and pseudoaneurysms.
We can see patients with arteritis
or perhaps problems caused as a result of trauma.
Ultrasound does give us the best of both worlds in
that we get the specific information on disease locations
severity with both the anatomy and physiology,
and certainly in addition to symptomatic patients,
we evaluate our asymptomatic patients prior
to certain operative procedures such as the creation
of a hemodialysis access graft,
or use of an artery for coronary artery bypass graft.
Thank you very much.