Pseudoaneurysms: Diagnosis and Treatment - HD

Diagnosis and Treatment of Pseudoaneurysms and Arteriovenous Fistulas

I am John Rito and I'm going to talk about the diagnosis
and treatment of pseudo aneurysms
and arterial venous fistulas.

For the next few minutes, I'm going
to describe the findings associated with these two entities
that usually occur after femoral artery injuries.

We'll talk a little bit about thrombin injection
for treatment of pseudo aneurysms
and some of the complications that can arise.

And I'm gonna finish up by showing some challenging cases.

Iatrogenic Femoral Artery Injuries

Most of you know that.
Iatrogenic femoral artery injuries occur up to about 2%
after procedures
and the incidence related to use of larger catheters,
more complex procedures and the use of anticoagulation.

Early diagnosis obviously important
to avoid potential complications.

And some of those complications include hematoma,
pseudo aneurysm, AV fistula, arterial dissection,
and arterial thrombosis.

And these things can then in turn cause local pain.
You can have a infection be related to the procedure.
Obviously you can have nerve
or venous compression distal ischemia
and if you have a large AV fistula,
patient may have congestive heart failure.

Pseudoaneurysms: Description and Diagnosis

Now most of seen pseudo aneurysms, you recognize these
as vascular masses connected to the underlying artery,
usually the femoral artery
after a femoral puncture by a track or a neck.

And again, this results from a hole in the wall from the
procedure which allows the escape of blood under pressure,
which is then confined
by the surrounding soft tissues and hematoma.

And this image was created by one of my sonographers.
We love using B flow.
You really can see the hemodynamics of a lot of vascular
abnormalities and this shows the swirling that occurs
inside the pseudo aneurysm cavity.

Now studies have shown that
probably the most important predisposing factor
for the formation of a pseudo aneurysm is
insufficient manual compression.
After the procedure, less than five minutes
of compression increases your risk.

Obviously the more complex the procedure,
the greater the risk of pseudo aneurysm.

So use of intraaortic balloon pumps,
arteriovenous hemo filtration,
stent placement also increases your risk.

So here's another example of a pseudo aneurysm.
Obviously in real time we see the swirling.
You've seen a couple of examples of this already.
We showed you one with regard to a renal transplant.

After a procedure you get that classic yin yang pattern.
And again, you wanna look for the track
or the neck that communicates between the underlying artery
and the pseudo aneurysm cavity.

In real time on color doppler, you can see the to
and fro that occurs.
Blood flow goes into the cavity during systole
because of the higher pressure gradient.

And then as the pressure reverses,
you have reversal flow back into the underlying artery.

You can see that on color doppler
because the color changes from red to blue
and you can easily see it
with pulse doppler when you place the sample volume in the
neck where those changes become very obvious, forward flow,
then reverse flow according to the cardiac cycle.

Now you can have complex pseudo aneurysms
with multiple lobes.

Here's an example of multiple lobes in series
and it's very important when you scan these patients
that you identify the underlying artery and vein.
That way you don't miss part of the abnormality.

And no matter where you sample across that chain
of pseudo aneurysms, you will see to and fro flow
and obviously they can occur in different locations.

Here's a patient that has a large pseudo aneurysm
after an axillary puncture.

And this was treated with a balloon
because this was not deemed to be compatible
for a thrombin repair because it wasn't entirely visualized.

Treatment Options for Pseudoaneurysms

So there are a number of different treatment options
for pseudo aneurysms.

First you can take a conservative approach
and see if the pseudo aneurysm will spontaneously thrombose
and I will do that for pseudo aneurysms
that are a centimeter or less.

Although I don't have any series that confirms the value
of using the one centimeter cutoff.

This is something I've been doing for years
and it seems to work pretty well.

Many of these will spontaneously go away when they're small.

Obviously if they're complex
or not amenable to thrombin injection
or compression repair, they may go on to surgical repair.

Ultrasound guided compression repair was possible years ago,
but we no longer do those
because those same patients are typically amenable
for thrombin injection.

And for those unusual cases like the one I just showed you
when we had that large axillary pseudo aneurysm though may
go to the interventional suite and have a balloon occlusion
or other similar technique.

Studies on Spontaneous Thrombosis

Here's a study that was done by Eric Paulson years ago
where he looked at several factors
to see which pseudo aneurysms would spontaneously thrombose
and he came up with some factors, small size,
long narrow neck, the age less than a month,
but he concluded they really weren't reliable color Doppler
features to determine which pseudo aneurysms will
spontaneously thrombose.

A similar study was also done looking at other factors.
And in this study the only factor that was felt
to be reliable, according to this author, was the length
of the neck that was less than one centimeter.

It was a relatively large series from the Journal
of Vascular Surgery, which looked at 196 pseudo aneurysms,
81 AV fistulas
and nine combined lesions to see which ones
required surgical repair
and which ones can be followed
to see if they would spontaneously thrombose.

The ones that went on to surgical repair were the ones
that should be treated that way because they were very large
or they were expanding, causing severe pain
or nerve compression or couldn't be followed up.

So those patients were treated by the surgeon,
the others were followed
and that was a group of 147
vascular abnormalities.

And you can see that 89%
of the pseudo aneurysms in this series spontaneously thrombosed
and maybe a little surprisingly 81% of the 80 AV fistulas,
he's very high flow states also spontaneously thrombosed.

14% of that group ended up going to surgery
and there were no significant complications.

Thrombin Injection for Pseudoaneurysms

Which brings me into the discussion of thrombin repair,
which is really our mainstay
for the treatment of pseudo aneurysms.

Obviously a non-operative alternative.

And for these we use a relatively small needle 22 gauge
needle that we place into the pseudo aneurysm cavity
directly under ultrasound guidance.

And in this image you can see the needle very well
with its tip placed within the cavity.

Once you've identified the needle location,
then you can inject the thrombin directly into the cavity.

While we watch typically with color doppler on
and in most cases we experience immediate thrombosis
of the pseudo aneurysm and we have found it to be very fast
and effective treatment for these lesions.

One of the first articles
that came out describing the technique came from Kang in his
group in the Journal of Vascular Surgery we had,
he had a series of 21 pseudo aneurysms.

20 of these were successfully treated with one cc
or less of thrombin,
again injected directly under ultrasound observation.

Most of them treated under 20 seconds, five
of which required a second injection.

And in his initial study
he described no complications or recurrences.

When we do these procedures, we have
to typically assess the anatomy
of the pseudo aneurysm in a similar manner that we did
for ultrasound guided compression repair.

We wanna assess the location, the size,
and of course the neck.

We'll discuss the procedure with the patient
and obtain informed consent.

Because of the possibility of a complication,
we don't give any premedication
and anticoagulation is not a contraindication.

We published this series years ago
and this was a series of 40 consecutive patients
that all had initial thrombosis after thrombin injection.

In this series we used an injection of just about half a cc
with a 22 gauge needle.

One of these patients required a second injection
because it was a complex lesion
and we had one complication, we had a recurrence
in the same patient,
because the needle tip wasn't very well seen,
patient eventually had a thrombosis
of the underlying artery.

And after treatment in the interventional suite developed a
second pseudo aneurysm.

So very important lesson learned there that you need to know
where the lesion tip is before you do the injection.

Here's one of our cases again,
you can see the pseudo aneurysm arising from the
common femoral artery.

The neck was well visualized and
after the injection you can see it's been
converted to a hematoma.

There's no flow in the lesion.

And we document patency in the underlying artery
and vein after the injection.

Here's another example. Here's a bi lobed pseudo aneurysm.
The artery's down. Here's the common femoral artery
above the bifurcation.

Here's one lobe, here's a second lobe.

And again, the objective here is
to place the needle in the most proximal collection because
after the thrombosis of that lesion,
the no flow will go into the more peripheral lobe.

So you can thrombose that pseudo aneurysm
with a single injection.

And here with the color turned off,
you can see the tip of the needle.

And here I'm just gonna show you on these
clips what it looks like.

Here we have a pseudo aneurysm.
The neck is over here
and here it with the color turned off,
you can see we puncture the pseudo aneurysm cavity
and there's the tip of the needle.

Okay, so I think it's very important to turn the color off
so that you can see the needle tip very well.

Then once you've identified the needle
and you feel comfortable about its location away from the
neck, then you can go ahead and turn the color back on.

And what you can see here is the gush of thrombin
with the color turned on
and the immediate thrombosis of the cavity,
after which you can withdraw the needle
and you can see how quickly that occurs,
that in just a matter of seconds
and a single collection,
you have immediate thrombosis of the cavity.

Here's another example.
It's about a two and a half centimeter pseudo aneurysm.
Here's the neck. And again,
in real time you can see the needle tip.

Here's the injection. And just in a matter of seconds,
it is completely thrombosed.

Eric Paulson published another series years later
where he compared his results
between ultrasound guided compression
repairs and thrombin injections.

And although he had many fewer thrombin injections in this
series, I think the data makes sense in
that you have a higher success rate, 96% compared to 74%
with ultrasound guided compression repair.

These numbers are very similar to ours.

When we looked at our initial series, the time
of treatment is six seconds compared to 42 minutes.

But that doesn't take into account the time of preparation
for the thrombin repair, including the
reconstitution of the thrombin.

And in this series, he describes no complications.

There was a series that came out of Boston
where they looked at 54 pseudo aneurysms that they treated
with thrombin and found that for all the simple
unilocular pseudo aneurysms, of which they were 45,
they were all successfully treated with a single injection
with no complications
and felt there was no need for ultrasound follow up.

But in his group of complex multilocular pseudo aneurysms,
four out of the nine were failures
because he required more than a single injection.

And he concluded after reviewing these cases, that
of course he should be injecting the most proximal lobe
because if you can knock that out, then
of course you can thrombose the entire collection.

So that's of course really the optimal strategy when you
have a complex pseudo aneurysm.

These cases, he recommended ultrasound follow-up
because he felt they were more complex.

In my series, we always do follow up
and I'll show you why in just a few moments.

Now here's a very large pseudo aneurysm.
There's about a nine centimeter bi lobe pseudo aneurysm
and you can see flow in both cavities.

And again, what I'm going to do here is I turn the color
off, I placed the needle tip,
you can see the arrow in the more proximal lobe.

And after injection, I've just completely thrombosed this
very large pseudo aneurysm.

Now we've also treated pseudo aneurysms away from the groin.

And this was one, I have to say I
was a little reticent to treat.

Initially this was a 28-year-old girl with lupus
and had a radial artery pseudo aneurysm
after an arterial puncture.

And I have to say I was a little concerned when they asked
me to do a thrombin injection
of this radial artery pseudo aneurysm.

And I only offered to do it in the presence
of the vascular surgeon who wanted the procedure.

And I said, listen, if I have a problem,
at least you are there to take the patient to surgery.

And I'd like to, and I'm happy
to say it went pretty well after the injection.

You can see we had a complete thrombosis
and the radial artery was patent afterwards.

But I would be careful on cases like this
because the risk is probably higher,
particularly when you don't have a very well-defined
pseudo aneurysm neck.

This is our series
that we published this year looking at recurrence rates
because there's nothing in the literature say
how often did these things come back?

So we looked at 262 consecutive cases.

Our overall success rate for thrombin repair was 86%
and our recurrence rate was almost 11%.

I was surprised that it was so high
because as many of these cases go on
and I don't see them all,
and I certainly not, I don't get follow up in all of these.

And we found that of these 11% of recurrences we found
that the factors that were seemed
to be the most important were large pseudo aneurysm size
and thrombocytopenia.

Our complication rate was 3%.
And this was related to five cases
that had vascular thrombosis
and two that ended up developing an infection.

Complications and Recurrences in Thrombin Injection

So here's one of those cases.
Here's one of our recurrences
and here's a 62-year-old status post cardiac cath.

And this was a complex femoral artery pseudo aneurysm,
the artery's down here, here's one lobe,
here's this a second and then a third.

So you could see this three together and there's the to
and fro flow and we injected it in the most proximal lobe
right down by the neck and we injected there.

And you can see that as is often the case,
there's a little bit of a residual neck.

Because we're not injecting into the neck, we try
to avoid the neck because if you inject toward the neck,
then you run the risk of getting the thrombus
into the underlying artery.

And thrombosis in the artery are causing
distal embolization.

So seeing a residual neck is fairly common
and that's one reason why we follow them.

And in follow up, we saw that there was
that this neck grew a small new head
and it required treatment once again.

And here's the follow up, we re-treated it
and it did not recur a second time.

Now Lennox in the Journal of Vascular Surgery,
described the complications that may occur.

And we already talked about the potential
for arterial occlusion when you inject toward the neck
or you may have embolization of thrombin material
causing distal occlusion.

And he felt that these major complications may be related
to the dose, the rate, the size of the neck,
and the location of the needle tip.

And although it may be related to the dose
or the rate, I don't think,
I think those are very minor factors.

I think what you really need to be careful with is the size
of the neck and making sure that you define a neck
and the location of the needle tip as we already discussed.

Interestingly, he described a technique
of compressing the neck during the injection,
which kind of makes sense.

It's a combined compression repair
when you do the injection.

So you can't get contrast in the neck if it's compressed.

And I've tried it but I found it to be uncomfortable
for the patient for myself, change the anatomy a little bit
and probably completely unnecessary
as I've never had that complication.

But I do avoid cases like this.

Here was a case that was sent to me for a thrombin repair
and I said, where's the neck?

If you can't define a neck, then the risk
of causing a complication is going to be much higher.

And I think this is really a rent
or a hole in the artery rather than
a pseudo with a neck.

And yes, it is a pseudo aneurysm,
but I don't think it's amenable to thrombin injection.

I sent this one to surgery.

Now I'm gonna show you another case that we did treat, which
I didn't treat it, but I have to say,
because the neck is so small and clearly a pseudo aneurysm
and is a fair amount of peripheral thrombus,
you could see the yin yang flow in the center of the cavity
and a very short neck
that arises from the common femoral artery.

So what I'd like you to do is pay
attention to this injection.

You can see the needle tip very well
and it's kind of pointing toward the area,
the neck, but it's not in the neck.

But watch what happens with the, when it's injected,
it goes directly into the artery, okay?

Which is exactly the thing that we want to avoid, okay?

And for dramatic effect, I'll let you watch it again
because you're not gonna, hopefully
you'll never see this again.

This is the thing you wanna avoid, okay?

The good news is that there was thrombosis
of the pseudo aneurysm and there were no complications.

The patient was followed for a couple of days.

There were no immediate symptoms.

There were good distal pulses.

And when we had the patient come back, the patient was fine.

So I think he got away with one,
but I think that's the kind
of thing they have to be careful about.

Arteriovenous Fistulas

Okay, let's talk a few moments about arterial venous
fistula, which again is another complication
of femoral artery puncture.

Just a little less common.

We typically see them between the common
or deep femoral artery in the common femoral vein.

And again, as I mentioned before, if they're really large,
then you run the potential for congestive heart failure
or local or distal ischemia.

And we all know about fistulas, right?

These are communications directly
between the artery and the vein.

And you're gonna see continuous forward flow across the,
the pressure gradient from the artery to the vein.

Very low impedance.

High velocity flow is typically what we see
when the connections,
the fistulas themselves are very small, very tight.

We get very high velocity flow
and we get vibration of the surrounding tissues, right?

We see a color bruit artifact on our color display
and many times what we have to do is freeze the image
in diastole to actually see the communication
because in systole is all that color flash.

So here's another example of a fistula
between the femoral artery and vein.

And as you'd expect when you sample the artery,
you lose the high resistant phasic pattern
at the site of the fistula.

It's now a shunt pattern
because it's going from the
high pressure artery to the vein.

So it's a low resistance pattern in the artery
and the venous side no longer having
that nice phasic flow pattern
but is now pulsatile like the artery.

So here's an example of a 58-year-old status post cardiac
cath that presented with the right pelvic swelling.

And this is a nice one
because it's a relatively large fistula
between the external iliac artery and vein.

Obviously the puncture is a little high
and we can see the classic changes
in the artery in the vein.

The artery is no longer phasic
as we would expect in the iliac artery.

It's got a low resistance pattern.

And when you sample the external iliac vein,
it's arterialized.

So very simple diagnosis.

And if you place the sample volume within the fistula,
you get very high velocity flow here.

It's close to 500 centimeters per second.

Challenging Cases

Now let's get into some more interesting complicated cases.

Here's a 54-year-old
with a right groin mass status post cardiac cath.

Now you clearly can see
a classic pseudo aneurysm frozen in time.

It's beautiful yin yang pattern.

But what else do you look at?

I mean, the thing is, these are the things
that my sonographers may miss or get confused by
because they may just stop at the more obvious finding
on this particular image.

It's also very easy to see that there's also a communication
between the artery and the vein.

And what makes this more complicated in real time is the
tremendous bruit artifact
that's occurring at that location.

So by freezing it in diastole, you lose a lot of the noise
and you can see the abnormalities really well.

So here we are looking at this combined pseudo aneurysm,
AV fistula, which can occur particularly when there
are multiple punctures.

And you know, July and August when all the new residents
and fellows come on board, we tend to see more
of these abnormalities due to the fact
that there are multiple groin punctures
for a single procedure.

And here on the site of the fistula,
we have a high velocity low resistance pattern.

And in the neck of the pseudo aneurysm we get classic
to and fro flow.

And this one we treated with thrombin
because the neck was away from the fistula
and we had a good result you could see.

And then we waited for the fistula to spontaneously thrombose.

Okay, let's take a look at this case.

This is a little trickier. Here's a 74-year-old status post
groin catheterization presenting
with a pulsatile groin mass, a classic history
rule out pseudo aneurysm.

And this is what we see. So these are the images obtained
by my sonographer,
and you could see that there's this lobulated
abnormality arising from the femoral artery.

And you know, my sonographers, they love B flow.

They love power. Doppler's great give us great images.

And of course they have to sample the neck.

And here's the sample that was obtained in the neck
and there's the waveform and you can see how it's labeled.

Clearly they thought it was a pseudo aneurysm
and may have thought that this was to and fro flow.

Maybe some of you think it's to and fro flow, but it's not
because with to and fro flow you have a forward
and reverse alternating component.

They don't occur at the same time.

This is more of a mirror image artifact
where you have the same arterial component
above and below the baseline.

So it's not a to and fro waveform.

And probably the take home point here is
that if you don't get a to
and fro flow waveform in the neck,
then don't call it a pseudo aneurysm
'cause that's probably not what it is.

So although it was thought to be a pseudo aneurysm,
I was very suspicious of that
'cause the waveform wasn't right.

So I went back in
and I found that it's actually a complex
arterial venous fistula.

And although you may think that's semantics,
it makes a whole lot of a difference when you decide
how you're going to treat it.

'cause you don't wanna stick a needle full of thrombin in
that cavity 'cause I can tell you exactly
where it's gonna go and you figured that out.

So when you place the sample volume now
and you see without the mirror image, it's clearly
a high velocity low resistance pattern that it is a fistula
with a small pseudo aneurysm component built into it.

Now one more case.

Here's an 85-year-old with a pulsatile groin mass.

And this is even more confusing I think
for the group looking at it
because the anatomy was hard to see, right?

When these patients get punctured,
especially multiple times, there's a lot of swelling.

There's a lot of pain over the site
and it may be difficult to image.

So here, you know, the still image that was given to me.

And then when I went back and looked at it
because I couldn't figure out what they were showing me
and I see a little this like sparkling there
and I say, I'm not sure what that is.

It kinda looks like a pseudo aneurysm.

And I went in there and took a waveform
and that's what I saw.

So I said, certainly not to
and fro not exactly sure what I'm looking at yet.

So looking around, I have this sort of color bruit
over the site of the puncture.

Of course, that's the key to doing these studies.

Look for the puncture and you put the probe on top of it.

You don't have to go fishing around
looking for the abnormality.

You go where the puncture site
and at the puncture site you see all this color coloring.

And so I sample around that
and you could see I get this sort
of arterialized flow pattern.

So here's a little bit of a clear image.

What's the diagnosis?

Now you're starting to see the communication, right?

You're starting to see the loop that's going on here
and why we got such a low resistance flow pattern.

'cause it's not a pseudo aneurysm,
but a very complex arterial venous fistula.

Okay? So it took a few minutes to get that image
because of all the artifact and because of the pain
and the swelling, but clearly a, it's a fistula
and that we're not gonna treat this with thrombin.

Conclusion

Okay? So I'm gonna conclude here.

My time's up duplex
and color doppler valuable
for the diagnosis of pseudo aneurysm.

And AV fistula helps us to distinguish other causes
of pulsatile groin mass, such as a hematoma.

And as you've seen and probably know
that thrombin injection is rapid effective treatment
for the repair of pseudo aneurysms.

Thank you very much.