Classification of Endoleak and Followup after EVAR with CEUS - SD

Classification of Endoleaks Using Contrast-Enhanced Ultrasound

The next topic, we will speak about the classification of endoleaks by using contrast enhanced ultrasound.

Of course, there's a couple of studies in the past that show that the use of contrast, not that the use of endovascular repair is as good as open repair and there was a British ERA trial and also these dream study.

Complications After Aortic Stent Graft

If you speak about complication after aortic stent graft, we think about complication in the early period like hematoma infection and also end. That could appear early and also in the late phase.

But in the late phase of course we have also problems about occlusion.

Contrast Injection Technique

If we think about how much contrast is necessary for do this examination, same like we do it with normal aortic pathologies, we inject one CCC of contrast follow by 10 C of seline solution.

A good trick is to use a big vein co vein and there inject the contrast trait not over the corner. Otherwise a couple of bubbles will be destroyed.

And also don't forget to flow again with seline solution afterwards.

Documenting a Normal Stent Graft

What kinds of stent graft we have to document?

If you look at the normal stent graft, starting with this examination, we see in the IL view here, the aortic aneurysm, we see the two legs of the stent graft and of course we see here in the middle the main body of the stent graft.

In this case we couldn't see any endo leak and this is also good for documentation.

It is also important to look at the second view because sometimes you have a good chance to miss an endo leak if you only look on the Exel view.

So therefore it's important to look at the main body of the stent graft and look at the right and left leg of the stent graft in order to detect any endo leaks.

If there is no end leak normal, the aortic aneurysm should be appear black and no contrast uptake in this aneurysm and in your report.

Therefore, it's very important to measure the maximum diameter of these aneurysm.

Therefore you make the measurement and document that the stent graft as well.

And this must be fixed in your report because you don't know if the aneurysm will grow or not grow if this is not measured.

Types of Endoleaks

If we speak about endoleaks, we can think about type one, and type two, three and four.

Starting with endoleaks, first of all we have to think about whether it's an early end, which appear the first study days after implantation or late, second endoleak that appears later than 30 days.

Just a short overview about endoleaks Type one A, type two about inferior mesenteric artery or lumbar artery type one B, for the distal stent or type three over connection or junction of the stent graft.

Case Examples of Endoleaks in Contrast-Enhanced Ultrasound

Now I show you a couple of cases. How does these endoleaks look like in contrast enhanced ultrasound?

You can also think about we are able to see these endoleaks by conventional gray scale image or color doppler.

Type One A Endoleak

Starting with this huge aneurysm, we see the stent graft inside.

We using the next step. We look for color doppler, we see a signal here.

There's not a signal that means that this patient has maybe occlusion of one of the leg or it's an artifact. You never know.

Then we of course look on the longitudinal or al view here and we also look in the color.

So the solution is staying type one A, but could you see it normally diagnosis stop here if you don't use contrast.

Did you see any end leak? Probably not because I also don't see it. No.

Starting with contrast we'll see the contrast uptake here. We'll see the other stent also with contrast uptake. So no occlusion of stent graft.

We have a timeframe up to three to four minutes. If we inject one CCC of contrast plenty of time, then we look and change the view.

Here's the proximal part of this stent graft. Did you see it?

Now we can also magnify it. And there it is, type one, a endo leak.

We couldn't see it with color doppler, we couldn't see it with power doppler. Even if we give our best no chance.

Type Two Endoleak

Now we come to the most of endo leaks. That's called type two.

You can decide whether you have got only one supplying artery, then it will be called two A.

If you have got two supplying artery for example, if it's a inferior mesenteric artery and lumbar artery will be called two B.

The most time you have only go about two A, which we are feeding over the lumbar artery or the inferior mesenteric artery starting with gray scale.

Did we see any liquids in the aneurysm? So no that in rec sign in gray scale Look again with color doppler here seems to be that there's a little bit liquid and moving in color blood but of course due to apposition of this stent graft in the aneurysm sac, sometimes we have also artifacts that look very similar like these end leak here.

So the next step we inject contrast. We see the filling of the two stent legs over time there the first contrast arrived take a little bit due to the fact that at two A the way of blood is much longer.

The appearing time is a little bit later in comparison to the appearing time in the stent graft.

And there you see the filling of contrast. Of course we can optimize the image. See it again. There it is.

And also if we look on the second view, we'll see how much contrast are he inside.

And if you remember the gray scale image, we couldn't see so much fluid inside in the aneurysm sac.

Type Three Endoleak

Type three endoleak is very easy if you have got a type three endoleak, the contrast appears the same time as the contrast appears in the aortic stent graft.

If it's the same time it could not be two A or two B Starting with gray scale then we see here in color doppler some sign that there must be huge endoleak.

But how do we know that's really a type three endoleak not type two leak of inferior mesenteric artery.

So we inject contrast and see immediately here from this part of the junction of the stent graft, the contrast got out of this stent graft in the aneurysm you'll see how fast the contrast appears just less than a second later it's in the aneurysm.

Typical for type three endoleaks.

Type Four Endoleak

And the last one, type four is a very uncommon end leak. It's really very rare case. We have only seen it once starting with gray scale again see the aortic stent graft inside.

Sometimes if you have got a good machine you are able to see power doppler some flow here out of the stent graft.

But the question is whether the flow come from the stent graft or from a feeding vessel.

So we inject contrast and you see couple that is so out of this stent graft, some small bubbles go in the aneurysm after optimizing the coagulation of this patient, this endoleak was occluded.

A very helpful trick is, here it also setting we optimize the image. You see the filling whether but there are still a lot of contrast in if you have got less contrast in and then burst it, you'll see the small bubbles moving Like we do it here you see single bubbles there you see also the flow direction.

Very very sensitive tool for detection. This kind of endoleak.

Detection of Occlusion

The next part which is very helpful of course occlusion starting with this patient. We see of course in gray scale the aortic stent graft. We see the aneurysm here.

Then we use the step by step technique color doppler. We see nice filling of the right iliac stent leg.

But on the left side we couldn't see any signal. But remember we are already a couple of cases where we wasn't able to see the signal. Normal stent grafts. So questions an artifact.

Of course if you have clinical experience can preparation of the femoral artery, you know exactly if the stent graft is open or not open 'cause you get a feedback by your fingers.

And if we inject contrast, we'll see that only one part of this stent graft is open.

And of course in this case it's very helpful to change the view. Here we see the main body of the stent graft.

Here's one leg of this graft is open and here is the other leg, main body and here the other leg of the graft which we used.

Studies and Conclusion

In conclusion we can say there's a couple of studies which show that the use of contrast ultrasound is helpful. Sometimes it's more sensitive comparison to CTA or DSA in this patient.

In this study the order compares ultrasound in comparison to CTA and it said that we have seen a couple of end leaks which was not confirmed by C ms M MS CTA but the DSA show that contrast and ultrasound said the truth that was really an end leak.

There's also another study which compare color doppler in comparison to contrast ultrasound. And if we look here for color doppler sensitivity, it's less we have got the same results.

I don't agree they do need a double dose of contrast. This author compares single dose where the double dose and this he inject a half while 2.5 cc of contrast.

For my opinion, it's not necessary if you have got a high end machine one cc of better because you get less signal but without overriding artifact.

Fact we have also done a couple of studies in this study When we started our gold standard was CT, therefore we have seen more endoleaks in comparison to the ct.

But due to the definition of our study, the gold standard was ct. If CT said no endo leak, it wasn't an endo leak but we have seen this.

So that was a breakthrough point for the ultrasound because all surgeons believe us and see it.

But if we compared, the specificity was not as high because the gold standard was ct.

But I will show you another couple of cases where you can from the study patient and you can make an all mind and really see that there are endoleaks which was not confirmed by CT even with an open endoleak.

So in conclusion we can say this technique is very helpful for detection of endoleak and aortic lesion, especially if you think about occlusion.

Very powerful tool and also if you think about radiation and iodinated contrast this patient, this contrast make no damage on the kidney function.

This tool is a very fast, minimal, innovative technique which is really reliable and it's a good additive in comparison to CTA and we are also change our study protocol that more and more patient will get these examination in comparison to the past.

Thank you much for attention.